CN119253163B - Energy storage devices and electrical equipment - Google Patents

Abstract

The application discloses an energy storage device and electric equipment, the energy storage device comprises a shell, and a battery cell and end cover assembly which are arranged on the shell. The battery cell comprises a battery cell body, a first tab group and a second tab group, wherein the first tab group and the second tab group are led out from the side face of the battery cell body. The end cover assembly comprises a first pin and a second pin, wherein the first pin comprises a first transfer part, and the first transfer part and the first tab group are provided with overlapping parts. The second pin comprises a second switching part. Which has an overlapping portion with the second tab set. The first tab group comprises a first outer side surface, and the ratio of the width of the overlapping part of the first tab group and the first transfer part to the linear distance from the first outer side surface to the central axis of the length direction of the battery cell is more than or equal to 5/7 and less than or equal to 6/7. The second lug group comprises a second outer side surface, and the ratio of the width of the overlapping part of the second lug group and the second switching part to the linear distance from the second outer side surface to the central axis of the length direction of the battery cell is greater than or equal to 4/7 and less than or equal to 5/7.

Description

Energy storage device and electric equipment

Technical Field

The application relates to the technical field of energy storage, in particular to an energy storage device and electric equipment.

Background

With the continuous progress of energy storage technology, consumers have increasingly demanded energy density inside energy storage devices. In order to improve the space utilization rate of the inside of the energy storage device, the existing high-capacity energy storage device mostly adopts a laminated type battery cell, and utilizes pins as conductive components to realize the electrical conduction of the battery cell and the polar column. However, the current conductivity of the anode pin and the current conductivity of the cathode pin are different, and when the sizes of the anode pin and the cathode pin are set to be the same and the sizes of the anode tab and the cathode tab are also set to be the same, the energy storage device has the difference of the current overcurrent capacity of the cathode pin and the anode pin, so that the consistency of the energy storage device is reduced.

Disclosure of Invention

The application provides an energy storage device and electric equipment, which can make up for the difference of current flowing capacity of a positive electrode pin and a negative electrode pin and improve the consistency of the energy storage device.

The embodiment of the application provides an energy storage device, which comprises a shell, a battery cell and an end cover assembly, wherein the shell comprises an opening. The battery cell is installed in the casing, the battery cell includes electric core body, first utmost point ear group and second utmost point ear group, the electric core body includes first side and second side, first side with the second side is followed the length direction of electric core body sets up in opposite directions, first utmost point ear group is followed first side draws forth, second utmost point ear group is followed the second side draws forth. The end cover assembly is arranged at one end of the battery cell and sealed at the opening, the end cover assembly comprises a first pin and a second pin, the first pin comprises a first switching part, the first switching part is overlapped on the first side face, the first tab group is coated and connected with the first switching part, the first tab group and the first switching part are provided with overlapped parts, the second pin comprises a second switching part, the second switching part is overlapped on the second side face, the second tab group is coated and connected with the second switching part, the second tab group and the second switching part are provided with overlapped parts, and the size of the first switching part is unequal to that of the second switching part.

The first tab group comprises a first outer side face, the first outer side face faces away from the first switching portion, the linear distance between the first outer side face and the central axis of the length direction of the battery cell is D1, the width of the overlapping portion of the first tab group and the first switching portion in the width direction of the battery cell is D2, and the ratio of D2 to D1 is greater than or equal to 5/7 and less than or equal to 6/7.

The second lug group comprises a second outer side face, the second outer side face faces away from the second switching part, the linear distance between the second outer side face and the central axis of the length direction of the battery cell is D3, the width of the overlapping part of the second lug group and the second switching part in the width direction of the battery cell is D4, and the ratio of D4 to D3 is greater than or equal to 4/7 and less than or equal to 5/7.

It can be understood that in the related art, since the material of the positive electrode pin and the material of the negative electrode pin are different, the conductive properties of the positive electrode pin and the negative electrode pin have differences. When the sizes of the positive electrode pin and the negative electrode pin are set to be the same and the sizes of the positive electrode tab and the negative electrode tab are also set to be the same, namely, the contact area of the positive electrode tab to the positive electrode pin is equal to the contact area of the negative electrode tab to the negative electrode pin, therefore, the current flowing capacity of the negative electrode pin and the current flowing capacity of the positive electrode pin are different. For example, under the condition that the anode pin and the cathode pin both meet the current flowing condition, the cathode pin can have the problem of excessive materials, so that the material utilization rate of the cathode pin is reduced, and the consistency of the energy storage device is not facilitated. Or under the condition that the current flowing through the negative electrode pin is just satisfied, the positive electrode pin with the same size as the negative electrode pin can bear higher heat when the current flows through the negative electrode pin, and the service life of the positive electrode pin is generally lower than that of the negative electrode pin along with repeated charging and discharging of the battery core, so that the consistency of the energy storage device is reduced.

In the embodiment of the application, the first pin and the second pin have different sizes, and the first tab group and the second tab group also have different sizes, so that the widths of the contact parts of the first tab group and the first pin are different under the condition that the current overcurrent requirements of the first tab group and the first pin are met. Meanwhile, under the condition that the requirements of current flowing through the second lug group and the second pin are met, the widths of the contact parts of the second lug group and the second pin are also different, and the problem that the current flowing capacity of the first pin and the current flowing capacity of the second pin are different is solved. Specifically, the ratio setting of D2 to D1 not only avoids the overlapping of the first attaching sections of the two first tab groups in the length direction of the battery cell, but also ensures that the contact area between the first tab groups and the first switching part can meet the current flow, so that the problem that the local heating value of the first switching part is overlarge due to the fact that the contact area between the first tab groups and the first switching part is too small is avoided, and the influence of heat on the first pin is reduced. The ratio setting of D4 to D3 not only avoids the second attaching sections of the two second lug groups to overlap in the length direction of the battery cell, but also ensures that the contact area of the second lug groups and the second switching part can meet the current flow, so that the problem that the local heating value of the second switching part is overlarge due to the overlarge contact area of the second lug groups and the second switching part is avoided, and the influence of heat on the second pins is reduced. In addition, the influence of heat on the first pin and the second pin is reduced, so that the temperature consistency and the service life consistency of the first pin and the second pin are guaranteed, and the consistency of the energy storage device is further facilitated.

In one embodiment, the first tab group includes a plurality of first tabs, a plurality of first tabs are stacked along a thickness direction of the first tab group, a plurality of first tabs are pre-welded and cut by ultrasonic welding to form the first tab group, the second tab group includes a plurality of second tabs, a plurality of second tabs are stacked along a thickness direction of the second tab group, and a plurality of second tabs are pre-welded and cut by ultrasonic welding to form the second tab group.

When the first tab group and the second tab group are under the same welding power, the number of the first tabs and the number of the second tabs are not equal.

It is understood that when the first tab set and the second tab set are under the same welding power, the number of positive tabs of the first tab set and the number of negative tabs of the second tab set may not be equal. The number of the positive electrode tabs of the first tab group and the number of the negative electrode tabs of the second tab group can be reasonably matched according to actual welding power so as to be compatible with the condition that the numbers of the first tabs of the first tab group and the second tabs of the second tab group are different, ensure that a plurality of first tabs forming the first tab group can be welded thoroughly, improve the connection reliability of the first tab group and the first pins, and simultaneously ensure that a plurality of second tabs forming the second tab group can be welded thoroughly, and improve the connection reliability of the second tab group and the second pins.

In one embodiment, the first tab includes a first end tab, a surface of the first end tab before pre-welding is a first outer surface, a partial surface of the first end tab after pre-welding is the first outer side surface of the first tab group, and a linear distance from a position of the first outer surface to a position of the first outer side surface is smaller than a length of the first end tab;

The second lug comprises a second end lug, the surface of the second end lug before pre-welding is a second outer surface, the partial surface of the second end lug after pre-welding is the second outer side surface of the second lug group, and the straight line distance from the position of the second outer surface to the position of the second outer side surface is smaller than the length of the second end lug.

It can be understood that the situation that the formed first tab group is inconsistent with the current overcurrent of the first pin due to inconsistent lengths of a plurality of first tabs is avoided, and the plurality of first tabs forming one first tab group can be welded and combined and electrically conducted with the first pin. Meanwhile, the condition that the formed second lug group is inconsistent with the current overcurrent of the second pin due to inconsistent lengths of the second lugs is avoided, and the fact that the second lugs forming one second lug group can be welded and combined and electrically conducted with the second pin is guaranteed.

It can be understood that the condition that the linear distance from the position of the first outer face to the position of the first outer side face is smaller than the length of the first end tab is satisfied, and meanwhile, the condition that the linear distance from the position of the second outer face to the position of the second outer side face is smaller than the length of the second end tab is satisfied, so that the current overflow of the first tab group and the first pin and the current overflow of the second tab group and the second pin are consistent, the service lives of the first pin and the second pin tend to be consistent, and the consistency of the energy storage device is further facilitated.

In an embodiment, the number of the first tab groups is two, the two first tab groups are respectively located at two opposite sides of the width direction of the first transfer portion, and are bent towards the first transfer portion, each first tab group includes a first attachment section, the two first attachment sections extend oppositely along the width direction of the first transfer portion and are attached to the surface of the first transfer portion opposite to the first side surface, and the first attachment sections are connected with the first transfer portion through laser welding.

The number of the second lug groups is two, the two second lug groups are respectively positioned on two opposite sides of the width direction of the second switching part and are bent towards the second switching part, each second lug group comprises a second attaching section, the two second attaching sections extend in opposite directions along the width direction of the second switching part and are attached to the surfaces of the second switching part, which are opposite to the second side surfaces, and the second attaching sections are connected with the second switching part through laser welding.

It can be understood that the two first attachment sections are connected with the first transfer portion by means of laser welding and are electrically conducted, so that a current flow path between the first tab set and the first transfer portion is increased, and heat generated when current flows between the first tab set and the first transfer portion is dispersed. Meanwhile, the two second attaching sections are connected with the second switching part in a laser welding mode and are electrically conducted, so that a current flow path between the second lug group and the second switching part is increased, and heat generated when current flows between the second lug group and the second switching part is dispersed. The influence of heat on the first pin and the second pin is reduced, and the temperature consistency and the service life consistency of the first pin and the second pin are guaranteed.

In addition, the design of the first tab group avoids the increase of the manufacturing cost of the first tab group due to the overlong length of the first tab group. Meanwhile, due to the design of the second lug group, the increase of the manufacturing cost of the second lug group caused by the overlong length of the second lug group is avoided.

In an embodiment, each of the first tab groups further includes a first lead-out section and a first middle section, the first lead-out section and the first side are connected and electrically conducted with the cell body, the first middle section is connected with the first lead-out section and is connected with the first attachment section in an included angle, the first middle section has the first outer side, the first transfer portion includes a first transfer inner face, and the first transfer inner face faces the first lead-out section and is spaced from the first side.

Each first tab group further comprises a second leading-out section and a second middle section, the second leading-out sections are connected with the second side faces and are electrically conducted with the battery cell body, the second middle sections are connected with the second leading-out sections and are connected with the second attaching sections in an included angle mode, the second middle sections are provided with second outer side faces, the second switching parts comprise second switching inner faces, and the second switching inner faces face towards the second leading-out sections and are spaced from the second side faces.

It can be understood that the first lead-out section of the first tab set is electrically connected to the battery core body, and the first attachment section of the first tab set is electrically connected to the first transfer portion, so as to electrically connect the battery core body to the first pin. The first switching part is spaced from the first side surface so as to avoid short circuit between the battery cell body and the first switching part. The second leading-out section of the second electrode lug group is electrically conducted with the battery cell body, and the second attaching section of the second electrode lug group is conducted with the second switching part, so that the electric conduction between the battery cell body and the second pin is realized. The second switching part is spaced from the second side surface so as to avoid short circuit between the battery cell body and the second switching part.

In one embodiment, the thickness of the first attachment section is greater than or equal to 1mm and less than or equal to 2mm. The thickness of the second attaching section is greater than or equal to 1mm and less than or equal to 2mm.

It can be appreciated that the thickness of the first attachment section not only ensures that the plurality of first tabs can be thoroughly welded to form a stable first tab group when subjected to ultrasonic welding, but also ensures good welding of the first attachment section and the first transfer portion. The thickness of the second attachment section not only ensures that a plurality of second lugs can be thoroughly welded to form a stable second lug group when ultrasonic welding is carried out, but also ensures good welding of the second attachment section and the second switching part.

In an embodiment, the first tab group includes a first ultrasonic welding area and a first laser welding area, the first ultrasonic welding area and the first laser welding area are both located in the first attachment section, the first laser welding area is completely located in the first ultrasonic welding area, a ratio of an area of the first laser welding area to an area of the first ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the first laser welding area is completely covered on the first transfer portion.

The second lug group comprises a second ultrasonic welding area and a second laser welding area, the second ultrasonic welding area and the second laser welding area are both positioned on the second attaching section, the second laser welding area is completely positioned in the second ultrasonic welding area, the ratio of the area of the second laser welding area to the area of the second ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the second laser welding area is completely covered on the second switching part.

It can be understood that the area of the first laser welding area is smaller than that of the first ultrasonic welding area, so that the incidence of laser energy generated when the first attachment section and the first transfer part are subjected to laser welding to the first outer side surface is avoided, the reflection of the laser energy by the smooth surface is avoided, the waste of the laser energy is reduced, and the welding effect of the first tab group and the first pin during laser welding is ensured. Meanwhile, the area of the second laser welding area is smaller than that of the second ultrasonic welding area, so that laser energy generated when the second attachment section and the second switching part are subjected to laser welding is prevented from being incident to the second outer side surface, reflection of the laser energy by a smooth surface is avoided, waste of the laser energy is reduced, and the welding effect of the second electrode lug group and the second pin during laser welding is ensured.

In one embodiment, the first laser welding area includes a first short side and a first narrow side, the first ultrasonic welding area includes a first long side and a first wide side, the first long side is parallel to the first short side, a distance between the first long side and an adjacent first short side is greater than or equal to 2mm and less than or equal to 5mm, the first wide side is parallel to the first narrow side, and a distance between the first wide side and an adjacent first narrow side is greater than or equal to 1mm and less than or equal to 2mm.

The second laser welding area comprises a second short side and a second narrow side, the second ultrasonic welding area comprises a second long side and a second wide side, the second long side is parallel to the second short side, the distance between the second long side and the adjacent second short side is greater than or equal to 2mm and less than or equal to 5mm, the distance between the second wide side and the second narrow side is parallel, and the distance between the second wide side and the adjacent second narrow side is greater than or equal to 1mm and less than or equal to 2mm.

It can be appreciated that the orthographic projection of the first laser welding area on the first tab group is completely located on the first ultrasonic welding area, and the orthographic projection of the second laser welding area on the second tab group is completely located on the second ultrasonic welding area.

In one embodiment, the first tab set has a length of greater than or equal to 25.5mm and less than or equal to 29.5mm. The length of the second electrode lug group is greater than or equal to 22mm and less than or equal to 26mm.

It can be understood that when the first tab set is attached to the first switching portion, a contact area of the first tab set to the first switching portion is satisfied, so that a current flowing through the first tab set and the first pin is satisfied. When the second lug group is attached to the second switching part, the contact area of the second lug group to the second switching part is met, and therefore the current overcurrent of the second lug group and the second pin is met.

The embodiment of the application also provides electric equipment, which comprises the energy storage device, wherein the energy storage device supplies power for the electric equipment.

Drawings

Fig. 1 is an application scenario diagram of an energy storage device according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of an energy storage device according to an embodiment of the present application;

FIG. 3 is an exploded view of the energy storage device of FIG. 1;

FIG. 4 is a schematic view of the structure of the first and second pins of the end cap assembly of the energy storage device shown in FIG. 3;

FIG. 5 is a schematic diagram of a partial structure of a battery cell in the energy storage device shown in FIG. 3;

FIG. 6 is a schematic view of a partial structure of the battery cell in the energy storage device shown in FIG. 3 at another angle;

FIG. 7 is a schematic cross-sectional view of a portion of the structure of the energy storage device shown in FIG. 3;

FIG. 8 is a side view of a portion of the structure of the energy storage device shown in FIG. 2;

FIG. 9 is a schematic cross-sectional view of a portion of the structure of the energy storage device shown in FIG. 8;

FIG. 10 is a side view of a portion of the structure of the energy storage device of FIG. 2 at another angle;

fig. 11 is a schematic cross-sectional view of a portion of the energy storage device shown in fig. 10 at another angle.

The corresponding nouns of the reference numerals in the figures are: energy storage device 1000, housing 200, opening 201, receiving cavity 202, end cap assembly 100, end cap 10, top surface 11, bottom surface 12, first through hole 13, second through hole 14, lower plastic 20, upper surface 21, lower surface 22, first post through hole 23, second post through hole 24, first post 30, second post 40, first pin 50, first connection 51, first through hole 511, first attachment portion 52, first attachment inner face 521, first attachment outer face 522, first surface 523, second pin 60, second connection portion 61, second through hole 611, second attachment portion 62, second attachment inner face 621, second attachment outer face 622, second surface 623, cell 300, cell body 310, first side 311, second side 312, first tab set 320, first end tab a, first outer face 321, first inner face 322, first end 323, first lead-out segment 324, first attachment segment 325, second end cap assembly 52, and second end cap assembly first inner surface 3251, first outer surface 3252, first intermediate section 326, first inner side 3261, first outer side 3262, first ultrasonic welding region 327, first long side 3271, first wide side 3272, first laser welding region 328, first short side 3281, first narrow side 3282, second tab set 330, second end tab b, second outer surface 331, second inner face 332, second end face 333, second lead-out section 334, second attachment section 335, second inner surface 3351, second outer surface 3352, second intermediate section 336, second inner side 3361, second outer side 3362, second ultrasonic welding region 337, second long side 3371, second wide side 3372, second laser welding region 338, second short side 3381, second narrow side 3382, first powered device 4103000, second powered device 2000, first powered device 4200, second powered device 4200, and energy storage system 5000.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

In the present application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, e.g., as being fixedly connected, as well as removably connected, or as being integral, as being mechanically connected, as being electrically connected, as being communicable with each other, as being directly connected, as being indirectly connected through an intervening medium, as being in communication between two elements or as being an interaction relationship between two elements, unless specifically stated otherwise. And as used hereinafter, "identical," "equal," or "parallel" allow for some tolerance.

It should be noted that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying a number of technical features being indicated. Thus, a feature defining "first," "second," etc. can include at least one such feature, either explicitly or implicitly.

Because of the strong timeliness and space properties of energy required by people, in order to reasonably utilize the energy and improve the utilization rate of the energy, one energy form needs to be stored by one medium or equipment and then converted into another energy form, and the energy is released in a specific energy form based on future application. At present, the generation of green electric energy generally depends on photovoltaic, wind power, water potential and the like, but wind energy, solar energy and the like generally have the problems of strong intermittence and large fluctuation, which can cause unstable power grid, insufficient peak electricity consumption, too much electricity consumption and unstable voltage can cause damage to the electric power, so that the problem of 'wind abandoning and light abandoning' possibly occurs due to insufficient electricity consumption requirement or insufficient power grid acceptance, and the problem needs to be solved by relying on energy storage. The energy is converted into other forms of energy through physical or chemical means and is stored, the energy is converted into electric energy when needed and released, in short, the energy storage is similar to a large-scale 'charge pal', the electric energy is stored when the photovoltaic and wind energy are sufficient, and the stored electric power is released when needed.

Taking electrochemical energy storage as an example, the present application provides an energy storage device 1000, wherein a group of chemical batteries are arranged in the energy storage device 1000, chemical elements in the chemical batteries are mainly used as energy storage media, and the charge and discharge process is accompanied with chemical reaction or change of the energy storage media, namely, the electric energy generated by wind energy and solar energy is simply stored in the chemical batteries, and the stored electric quantity is released for use when the use of external electric energy reaches a peak, or is transferred to a place with short electric quantity for use.

The present energy storage (i.e. energy storage) application scenario is wider, including aspects such as (wind and light) power generation side energy storage, electric wire netting side energy storage, base station side energy storage and user side energy storage, the kind of the corresponding energy storage device 1000 includes:

(1) The large energy storage container applied to the energy storage scene at the power grid side can be used as a high-quality active and reactive power regulation power supply in the power grid, so that the load matching of electric energy in time and space is realized, the renewable energy consumption capability is enhanced, and the large energy storage container has great significance in the aspects of standby of a power grid system, relieving peak load power supply pressure and peak regulation and frequency modulation;

(2) The small and medium energy storage electric cabinet is applied to industrial and commercial energy storage scenes (banks, markets and the like) at the user side, and the main operation mode is peak clipping and valley filling. Because of the large price difference of the electricity charge at the peak-valley position according to the electricity consumption demand, after the user has the energy storage equipment, the energy storage cabinet/box is charged in the low-price period for reducing the cost, and the electricity in the energy storage equipment is released for use in the electricity price peak period, so that the purpose of saving the electricity charge is achieved.

It should be noted that, the above-mentioned devices including the energy storage device 1000, such as the energy storage container, the small and medium-sized energy storage electric cabinet, and the small-sized energy storage box for a user, may be understood as electric devices.

Referring to fig. 1, fig. 1 is an application scenario diagram of an energy storage device according to an embodiment of the present application.

The energy storage device 1000 provided by the embodiment of the application is applied to an energy storage system 5000, where the energy storage system 5000 includes a first electric energy conversion device 4100 (photovoltaic panel), a second electric energy conversion device 4200 (fan), a first electric device 3000 (power grid), a second electric device 2000 (base station) and the energy storage device 1000. The energy storage system 5000 further includes an energy storage cabinet, the energy storage device 1000 is installed in the energy storage cabinet, and the energy storage cabinet may be installed outdoors. Specifically, the first power conversion device 4100 may convert solar energy into electric energy during the low electricity price period, and the energy storage device 1000 is configured to store the electric energy and supply the electric energy to the first electric device 3000 or the second electric device 2000 during the peak electricity consumption period, or supply the electric energy when the first electric device 3000 or the second electric device 2000 is powered off/powered off. Second power conversion device 4200 may convert wind energy into electrical energy, and energy storage device 1000 may be configured to store the electrical energy and supply power to first powered device 3000 or second powered device 2000 during peak power usage, or to power first powered device 3000 or second powered device 2000 during power outage/power outage. The transmission of the electric energy can be performed by adopting a high-voltage cable.

It should be noted that, the devices including the energy storage device 1000, such as the first powered device 3000 and the second powered device 2000, may be understood as powered devices. The energy storage device 1000 supplies power to the electric equipment.

The number of the energy storage devices 1000 may be plural, and the plurality of energy storage devices 1000 may be connected in series or parallel with each other. In the present embodiment, "a plurality of" means two or more.

It is understood that the energy storage device 1000 may include, but is not limited to, a battery cell, a battery module, a battery pack, a battery system, etc. The practical application of the energy storage device 1000 provided in the embodiment of the present application may be, but is not limited to, the listed products, and may also be other application. For example, the energy storage device 1000 may be a secondary battery such as a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid (or lead-storage) battery, a lithium ion battery, or a polymer lithium ion battery. When the energy storage device 1000 is a single battery, it may be a cylindrical battery, a prismatic battery, or a battery of other shape. In this embodiment, the energy storage device 1000 is a square battery. Wherein, square battery is the secondary cell.

Referring to fig. 2 and fig. 3 together, fig. 2 is a schematic structural diagram of an energy storage device according to an embodiment of the application, and fig. 3 is an exploded structural diagram of the energy storage device shown in fig. 1.

For convenience of description, the width direction of the energy storage device 1000 is defined as the X-axis direction, the length direction is defined as the Y-axis direction, and the height direction is defined as the Z-axis direction. Wherein, X axis direction, Y axis direction and Z axis direction are mutually perpendicular two by two.

The terms of "upper", "top", "lower", "bottom", "left", "right", and the like in the description of the embodiments of the present application are described according to the orientations shown in fig. 2 of the present specification, and do not limit the energy storage device 1000 in the practical application scenario. Specifically, the positive direction facing the Z-axis direction is taken as the top of the energy storage device 1000, and the negative direction facing the Z-axis direction is taken as the bottom of the energy storage device 1000.

The energy storage device 1000 includes an end cap assembly 100, a housing 200, and a battery cell 300. The housing 200 has an opening 201 and is provided with a receiving chamber 202. The opening 201 communicates with the receiving chamber 202. The battery cell 300 is accommodated in the accommodating chamber 202. The end cap assembly 100 is mounted to one end of the battery cell 300 and sealed to the opening 201 to isolate the internal environment of the energy storage device 1000 from the external environment.

The end cap assembly 100 includes an end cap 10, a lower plastic 20, a first pole 30, a second pole 40, a first pin 50, and a second pin 60. The lower plastic 20 and the end cap 10 are stacked in the Z-axis direction. The length of the lower plastic 20 is the same or substantially the same as the length of the end cap 10. The width of the lower plastic 20 is the same or substantially the same as the width of the end cap 10. The first pole 30 and the second pole 40 are located at opposite ends of the end cap assembly 100 in the length direction, respectively. The first pole 30 is disposed through the end cap 10 and the lower plastic 20, and is connected to the first pin 50. The second post 40 is disposed through the end cap 10 and the lower plastic 20, and is connected to the second pin 60. The first pin 50 and the second pin 60 are located at opposite ends of the cell 300 in the length direction (i.e., the Y-axis direction), respectively. The first pin 50 is partially mounted to the lower plastic 20 and is located on a side of the lower plastic 20 facing away from the end cap 10. Another portion of the first pin 50 is connected to the battery 300. The battery 300 is electrically connected to the first terminal 30 through the first pin 50. The second pin 60 is partially mounted to the lower plastic 20 and is located on a side of the lower plastic 20 facing away from the end cap 10. Another portion of the second pin 60 is connected to the battery 300. The battery 300 is electrically connected to the second post 40 through the second pin 60. In this embodiment, the first electrode 30 is a positive electrode. The second post 40 is a negative post. In some embodiments, the first post 30 is a negative post and the second post 40 is a positive post.

In this embodiment, the end cap 10 is an aluminum optical member. The end cap 10 is an elongated sheet. The end cap 10 includes a top surface 11 and a bottom surface 12. The top surface 11 and the bottom surface 12 are disposed opposite to each other in the thickness direction (i.e., Z-axis direction) of the end cap 10. The end cap 10 further comprises a first through hole 13 and a second through hole 14. The first through hole 13 and the second through hole 14 penetrate through the top surface 11 and the bottom surface 12. The first through holes 13 and the second through holes 14 are provided at intervals along the length direction (i.e., Y-axis direction) of the cap 10. The first through hole 13 is for the first pole 30 to pass through. The second through hole 14 is used for the second post 40 to pass through. The shapes of the first through holes 13 and the second through holes 14 may be, but not limited to, circular, polygonal, rectangular, etc. Illustratively, the first through hole 13 and the second through hole 14 are both circular in shape.

In this embodiment, the lower plastic 20 is made of an insulating material. The lower plastic 20 is an elongated sheet. The lower plastic 20 includes an upper surface 21 and a lower surface 22. The upper surface 21 and the lower surface 22 are disposed opposite to each other in the thickness direction (i.e., Z-axis direction) of the lower plastic 20. The lower plastic 20 further includes a first post through hole 23 and a second post through hole 24. The first and second post through holes 23 and 24 penetrate through the upper and lower surfaces 21 and 22. The first post through holes 23 and the second post through holes 24 are disposed at intervals along the length direction (i.e., Y-axis direction) of the lower plastic 20. The first pole through hole 23 is used for the first pole 30 to pass through. The second post via 24 is for the second post 40 to pass through. The shapes of the first and second post through holes 23 and 24 may be, but are not limited to, circular, polygonal, rectangular, etc. Illustratively, the first and second post through holes 23, 24 are both circular in shape.

The lower plastic 20 may include a first lower plastic 20 and a second lower plastic 20. The first lower plastic 20 and the second lower plastic 20 may be integrally formed. Or the first lower plastic 20 and the second lower plastic 20 may be formed separately.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a first pin and a second pin of an end cap assembly in the energy storage device shown in fig. 3.

In this embodiment, the first pin 50 is made of aluminum. The first pin 50 is a sheet. The first pin 50 includes a first connection portion 51 and a first transfer portion 52. The first connection portion 51 and the first transfer portion 52 are connected at an angle, and form an L-shaped structure. The first connection portion 51 is used for connecting with the lower plastic 20 and electrically conducting with the first pole 30. The first switching portion 52 is configured to be connected to the battery cell 300 and electrically connected to the battery cell 300. It can be appreciated that the first pin 50 is used to transfer the current of the battery 300 to the first terminal 30 through the first connection portion 52 and the first connection portion 51 in sequence.

Specifically, the first connection portion 51 has a first through hole 511. The first through holes 511 penetrate through both surfaces of the first connecting portion 51 in the thickness direction (i.e., the Z-axis direction). The first through hole 511 is used for the first pole 30 to pass through. The shape of the first perforation 511 may be, but is not limited to, circular, polygonal, rectangular, etc. Illustratively, the first perforations 511 are all circular in shape.

In this embodiment, the first transfer portion 52 is a rectangular thin plate. The first transfer portion 52 includes a first transfer inner face 521 and a first transfer outer face 522. The first transfer inner face 521 and the first transfer outer face 522 are disposed opposite to each other in the thickness direction (i.e., Y-axis direction) of the first transfer portion 52. The first connecting outer face 522 faces away from the first connecting portion 51. The first transfer portion 52 further includes two first surfaces 523. The two first surfaces 523 are disposed opposite to each other in the width direction of the first transfer portion 52. Both first surfaces 523 are connected to the first inner transition face 521 and the first outer transition face 522.

In this embodiment, the second pin 60 is made of copper. The second pin 60 is similar in structure to the first pin 50. The second pin 60 is a sheet. The second pin 60 includes a second connection portion 61 and a second adapter portion 62. The second connecting portion 61 and the second adapting portion 62 are connected at an included angle, and form an L-shaped structure. The second connection portion 61 is used for being connected with the lower plastic 20 and electrically connected with the second post 40. The second switching part 62 is used for being connected with the battery cell 300 and electrically conducting with the battery cell 300. It can be understood that the second pin 60 is used to transfer the current of the battery 300 to the second post 40 through the second switching portion 62 and the second connection portion 61 in sequence.

Specifically, the second connection portion 61 has a second through hole 611. The second through holes 611 penetrate through both surfaces of the second connecting portion 61 in the thickness direction (i.e., the Z-axis direction). The second through hole 611 is used for the second post 40 to pass through. The shape of the second perforation 611 may be, but is not limited to, circular, polygonal, rectangular, etc. Illustratively, the second perforations 611 are each circular in shape.

In this embodiment, the second adapting portion 62 is a rectangular thin plate. The second adapter 62 includes a second adapter inner face 621 and a second adapter outer face 622. The second transfer inner surface 621 and the second transfer outer surface 622 are disposed opposite to each other in the thickness direction (i.e., Y-axis direction) of the second transfer portion 62. The second transfer outer surface 622 faces away from the second connection portion 61. The second adapter 62 further includes two second surfaces 623. The two second surfaces 623 are disposed opposite to each other in the width direction of the second transfer portion 62. Both second surfaces 623 are connected to the second inner transition face 621 and the second outer transition face 622.

Referring to fig. 3, fig. 5 and fig. 6 together, fig. 5 is a schematic view of a partial structure of a battery cell in the energy storage device shown in fig. 3, and fig. 6 is a schematic view of a partial structure of a battery cell in the energy storage device shown in fig. 3 at another angle. In fig. 5, the dashed line indicates the boundary line between the first attaching segment, the first lead-out segment, and the first intermediate segment of the first tab group, in fig. 6, the dashed line indicates the boundary line between the second attaching segment, the second lead-out segment, and the second intermediate segment of the second tab group, and fig. 5 and 6 illustrate the state of the tab in the battery cell when the tab is not bent.

In this embodiment, the battery cell 300 is a laminated structure. The cell 300 includes a cell body 310 and a tab set. The battery cell body 310 is formed by stacking a positive electrode sheet, a negative electrode sheet, and an insulating film between the positive electrode sheet and the negative electrode sheet. The positive and negative electrode sheets each include a first portion coated with an active material and a second portion extending outwardly from the first portion that is not coated with an active material. The cell body 310 includes a first side 311 and a second side 312. The first side 311 and the second side 312 are disposed opposite to each other along the length direction (i.e., Y-axis direction) of the cell body 310. In this embodiment, the number of the battery cell bodies 310 is two. The two cell bodies 310 are connected in parallel along the X-axis direction.

The tab set includes a first tab set 320 and a second tab set 330. The first tab set 320 and the second tab set 330 are electrically connected to the battery cell body 310. The first tab set 320 is led out from the first side 311 of the battery cell body 310 and extends in a direction away from the battery cell body 310. The first tab set 320 is configured to be connected to and electrically connected to the first pin 50. The second tab set 330 is led out from the second side 312 of the battery cell body 310 and extends away from the battery cell body 310. The second tab set 330 is configured to be connected to and electrically connected to the second pin 60. In this embodiment, the number of the first tab set 320 and the second tab set 330 is two. Each first tab set 320 is led out from the first side 311 of one cell body 310. Each second tab set 330 leads from the second side 312 of one of the cell bodies 310. The first tab set 320 may be a positive tab set. The second tab set 330 may be a negative tab set. In other embodiments, the first tab set 320 may be a negative tab set and the second tab set 330 may be a positive tab set.

As shown in fig. 5, the first tab set 320 includes a first outer face 321, a first inner face 322, and a first end face 323. The first outer face 321 and the first inner face 322 are disposed opposite to each other in the thickness direction (i.e., X-axis direction) of the first tab group 320. The first end face 323 is connected to the first outer face 321 and the first inner face 322. The first end face 323 is distal to the first side face 311 of the cell body 310.

The first tab set 320 includes a plurality of first tabs (not shown). In this embodiment, the first tabs are positive electrode tabs, and each first tab corresponds to a second portion of the positive electrode sheet, which is not coated with an active material. Along the Y-axis direction, a plurality of first tabs on one cell body 310 are led out from the first side 311 of the cell body 310, and the plurality of first tabs are stacked in the thickness direction of the first tab group 320. The plurality of first tabs includes two first end tabs a. The two first end tabs a are close to opposite sides of the width direction of the battery cell body 310. The two first end tabs a and other first tabs located between the two first end tabs a are pre-welded and cut by ultrasonic welding to form a first tab group 320. The two opposite surfaces of the two first end tabs a form a first outer face 321 and a first inner face 322 of the first tab set 320, respectively.

In this embodiment, the material of the first tab may be aluminum. The length L1 of the first tab set 320 is greater than or equal to 25.5mm and less than or equal to 29.5mm, so as to satisfy the contact area of the first tab set 320 to the first transfer portion 52 when the first tab set 320 is attached to the first transfer portion 52, thereby satisfying the current flowing through the first tab set 320 and the first pin 50. It is to be explained that the length L1 of the first tab set 320 is a distance from the first side 311 of the battery cell body 310 to the first end 323 of the first tab set 320.

The first tab set 320 further includes a first lead-out section 324, a first attachment section 325, and a first intermediate section 326. The first intermediate section 326 connects the first exit section 324. The first lead-out section 324 is connected to the first side 311 of the battery cell body 310 and is electrically connected to the battery cell body 310. The first attachment segment 325 is remote from the cell body 310. The first attachment section 325 is welded to the first connecting portion 52 and electrically connected to the first connecting portion 52. The first middle section 326 is used for bending the first tab set 320, and the first middle section 326 is connected with the first attachment section 325 in an included angle, and forms an L-shaped structure. In this embodiment, the first lead-out section 324 is formed by a plurality of first tabs inclined toward the central axis of the cell body 310 in the length direction. The cross-section of the first lead-out section 324 is generally triangular in shape.

The first attachment section 325 includes a first inner surface 3251 and a first outer surface 3252. The first inner surface 3251 and the second outer surface 3352 are disposed opposite one another in the thickness direction of the first attachment segment 325. The first inner surface 3251 is for connection with the first transition portion 52. The first end face 323 is disposed on the first attachment section 325 and connects the first inner surface 3251 and the first outer surface 3252. The first end face 323 is remote from the first intermediate section 326. In this embodiment, the thickness of the first attachment section 325 is greater than or equal to 1mm and less than or equal to 2mm, which not only ensures that the plurality of first tabs can be thoroughly welded to form the stable first tab group 320 when ultrasonic welding is performed, but also ensures good welding between the first attachment section 325 and the first connection portion 52.

The first intermediate section 326 includes a first inner side 3261 and a first outer side 3262. The first inner side 3261 and the first outer side 3262 are disposed opposite each other in the thickness direction of the first intermediate section 326. In this embodiment, the thickness of the first intermediate section 326 is greater than or equal to 1mm and less than or equal to 2mm.

It should be noted that the first outer surface 3252 of the first attachment segment 325 and the first outer side 3262 of the first intermediate segment 326 form part of the first outer face 321 of the first tab set 320. The first inner surface 3251 of the first attachment section 325 and the first inner side 3261 of the first intermediate section 326 form part of the first inner face 322 of the first tab set 320.

As shown in fig. 6, the second tab set 330 includes a second outer face 331, a second inner face 332, and a second end face 333. The second outer surface 331 and the second inner surface 332 are disposed opposite to each other in the thickness direction (i.e., X-axis direction) of the second tab set 330. The second end surface 333 is connected to the second outer face 331 and the second inner face 332. The second end surface 333 is distal from the second side 312 of the cell body 310.

The second tab set 330 includes a plurality of second tabs (not shown). In this embodiment, the second tabs are positive electrode tabs, and each second tab corresponds to a second portion of the positive electrode sheet, which is not coated with an active material. Along the Y-axis direction, a plurality of second tabs on one cell body 310 are led out from the second side surface 312 of the cell body 310, and the plurality of second tabs are stacked in the thickness direction of the second tab group 330. The plurality of second tabs includes two second end tabs b. The two second end tabs b are close to two opposite sides of the width direction of the battery cell body 310, and are substantially symmetrically disposed about the central axis of the length direction of the battery cell 300. The two second end tabs b and other second tabs located between the two second end tabs b are pre-welded and cut by ultrasonic welding to form a second tab group 330. The two opposite surfaces of the two second end tabs b respectively form a second outer surface 331 and a second inner surface 332 of the second tab set 330.

In this embodiment, the material of the second tab may be copper. The length L2 of the second tab set 330 is greater than or equal to 22mm and less than or equal to 26mm, so as to satisfy the contact area of the second tab set 330 to the second adaptor 62 when the second tab set 330 is attached to the second adaptor 62, thereby satisfying the current overcurrent between the second tab set 330 and the second pin 60. It is to be explained that the length L2 of the second tab set 330 is a distance from the second side 312 of the battery cell body 310 to the second end 333 of the second tab set 330.

The second tab set 330 further includes a second lead-out section 334, a second attachment section 335, and a second intermediate section 336. The second intermediate section 336 connects the second lead-out section 334. The second intermediate section 336 is connected at an angle to the second attachment section 335 and forms an L-shaped structure. The second lead-out section 334 is connected to the second side 312 of the battery cell body 310 and is electrically connected to the battery cell body 310. The second attachment section 335 is remote from the cell body 310. The second attachment section 335 is welded to the second adaptor 62 and electrically connected to the second adaptor 62. The second middle section 336 is used for bending the second tab set 330. In this embodiment, the second lead-out section 334 is formed by a plurality of second tabs inclined toward the central axis of the cell body 310 in the length direction. The cross-section of the second lead-out section 334 is generally triangular in shape.

The second attachment section 335 includes a second inner surface 3351 and a second outer surface 3352. The second inner surface 3351 and the second outer surface 3352 are disposed opposite to each other in the thickness direction of the second attachment section 335. The second inner surface 3351 is for connection with the second adapter 62. The second end surface 333 is disposed on the second attachment section 335 and connects the second inner surface 3351 and the second outer surface 3352. The second end surface 333 is remote from the second intermediate section 336. In this embodiment, the thickness of the second attachment section 335 is greater than or equal to 1mm and less than or equal to 2mm, which not only ensures that the second tabs can be completely welded to form the stable second tab set 330 when the second tabs are ultrasonically welded, but also ensures good welding between the second attachment section 335 and the second adapter 62.

The second intermediate section 336 includes a second inner side 3361 and a second outer side 3362. The second inner side surface 3361 and the second outer side surface 3362 are disposed opposite to each other in the thickness direction of the second intermediate section 336. In this embodiment, the second intermediate section 336 has a thickness greater than or equal to 1mm and less than or equal to 2mm.

It should be noted that the second outer surface 3352 of the second attachment section 335 and the second outer side surface 3362 of the second intermediate section 336 form part of the second outer face 331 of the second tab set 330. The second inner surface 3351 of the second attachment section 335 and the second inner side surface 3361 of the second intermediate section 336 form part of the second inner face 332 of the second tab set 330.

In this embodiment, when the first tab set 320 and the second tab set 330 are under the same welding power, the number of positive tabs of the first tab set 320 is equal to the number of negative tabs of the second tab set 330, or the number of positive tabs of the first tab set 320 is unequal to the number of negative tabs of the second tab set 330. It can be appreciated that the number of the positive electrode tabs of the first tab group 320 and the number of the negative electrode tabs of the second tab group 330 can be reasonably matched according to actual welding power, so as to be compatible with the situation that the numbers of the first tabs of the first tab group 320 and the second tabs of the second tab group 330 are different, ensure that a plurality of first tabs forming the first tab group 320 can be welded thoroughly, improve the connection reliability of the first tab group 320 and the first pin 50, and simultaneously ensure that a plurality of second tabs forming the second tab group 330 can be welded thoroughly, and improve the connection reliability of the second tab group 330 and the second pin 60.

Referring to fig. 5, fig. 6 and fig. 7 together, fig. 7 is a schematic cross-sectional view of a part of the structure of the energy storage device shown in fig. 3. It should be noted that, fig. 7 illustrates an assembly structure of the battery core and the first and second pins, but does not refer to an assembly sequence of components in the energy storage device, and the first tab set and the second tab set illustrated in fig. 7 are both in a bent state.

The first pin 50 and the second pin 60 are both mounted to the battery 300. The first tab set 320 is bent and attached to the first adapting portion 52 of the first lead 50, and the second tab set 330 is bent and attached to the second adapting portion 62 of the second lead 60.

Specifically, the first converting portion 52 is stacked on the first side 311 of the battery cell body 310, and the first converting inner surface 521 of the first converting portion 52 faces the first lead-out section 324, and the first converting inner surface 521 is spaced from the first side 311 to avoid a short circuit between the battery cell body 310 and the first pin 50. The first transfer outer face 522 of the first transfer portion 52 faces away from the first side 311 of the cell body 310.

As shown in fig. 7, the two first tab groups 320 are located on opposite sides of the width direction (i.e., the X-axis direction) of the first tab portion 52, respectively. Each first tab set 320 is led out from the first side 311 of one cell body 310 and is bent towards the first converting portion 52. The first attachment sections 325 of the two bent first tab groups 320 extend oppositely along the X-axis direction, and the first end faces 323 of the two first tab groups 320 are opposite and spaced apart. The two first attachment sections 325 are attached to the first attachment portion 52, and the first inner surfaces 3251 of the two first attachment sections 325 are connected to the first attachment outer face 522 of the first attachment portion 52. The two first attachment sections 325 are connected to the first connection portion 52 by laser welding and electrically connected to increase a current flowing path between the first tab set 320 and the first connection portion 52, so as to be beneficial to dispersing heat generated when current flows between the first tab set 320 and the first connection portion 52.

It can be understood that the two first tab groups 320 are wrapped around and connected to the first transfer portion 52, and the two first tab groups 320 and the first transfer portion 52 have overlapping portions. Specifically, the first outer side 3262 of the first middle section 326 has a linear distance D1 from the central axis H-H of the cell 300 in the longitudinal direction. The width of the overlapping portion of the first adapting portion 52 and each first attachment section 325 in the width direction of the battery cell 300 is D2, that is, the linear distance between the first surface 523 of the first adapting portion 52 and the first end face 323 of the first attachment section 325 adjacent to the first surface 523 is D2. Wherein, the first surface 523 and the first end face 323 are both located on the same side of the central axis H-H in the length direction of the cell 300. The ratio of D2 to D1 is greater than or equal to 5/7 and less than or equal to 6/7, which not only avoids overlapping the first attachment sections 325 of the two first tab groups 320 in the Y-axis direction, but also ensures that the contact area between the first tab groups 320 and the first switching portion 52 can satisfy the current flowing, so as to avoid the excessive local heating value of the first switching portion 52 caused by the excessively small contact area between the first tab groups 320 and the first switching portion 52, and reduce the influence of heat on the first pins 50.

The second adapting portion 62 is stacked on the second side 312 of the battery cell body 310, the second adapting inner surface 621 of the second adapting portion 62 faces the second lead-out section 334, and the second adapting inner surface 621 is spaced from the second side 312 to avoid the short circuit between the battery cell body 310 and the second pin 60. The second transfer outer surface 622 of the second transfer portion 62 faces away from the second side 312 of the cell body 310.

As shown in fig. 7, the two second tab sets 330 are respectively located on opposite sides of the second adapting portion 62 in the width direction (i.e., the X-axis direction). Each second tab set 330 is led out from the second side 312 of one of the cell bodies 310 and is bent toward the second adapter 62. The second attachment sections 335 of the two folded second tab groups 330 extend in opposite directions along the X-axis direction, and the second end faces 333 of the two second tab groups 330 are opposite and spaced apart. The two second attachment sections 335 are attached to the second adapting portion 62, and the second inner surfaces 3351 of the two second attachment sections 335 are connected to the second adapting outer surface 622 of the second adapting portion 62. The two second attachment sections 335 are connected to the second adapting portion 62 by means of laser welding and electrically connected to each other, so as to increase a current flowing path between the second tab set 330 and the second adapting portion 62, and facilitate dispersing heat generated during current flowing between the second tab set 330 and the second adapting portion 62.

It can be understood that the two second tab sets 330 wrap around and connect to the second adaptor 62, and the two second tab sets 330 and the second adaptor 62 have overlapping portions. Specifically, the second outer side 3362 of the second middle section 336 has a linear distance D3 from the central axis H-H of the cell 300 in the length direction. The width of the overlapping portion of the second adapting portion 62 and each second attachment section 335 in the width direction of the battery cell 300 is D4, that is, the linear distance between the second surface 623 of the second adapting portion 62 and the second end surface 333 of the second attachment section 335 adjacent to the second surface 623 is D4. Wherein, the second surface 623 and the second end surface 333 are both located on the same side of the central axis H-H in the longitudinal direction of the cell 300. The ratio of D3 to D4 is greater than or equal to 4/7 and less than or equal to 5/7, which not only avoids overlapping the second attachment sections 335 of the two second tab sets 330 in the Y-axis direction, but also ensures that the contact area between the second tab sets 330 and the second switching portion 62 can satisfy the current flowing, so as to avoid the excessive local heating value of the second switching portion 62 caused by the excessively small contact area between the second tab sets 330 and the second switching portion 62, and reduce the influence of heat on the second pins 60.

It will be appreciated that the reduced effect of heat on the first and second pins 50, 60 is beneficial for ensuring temperature uniformity and service life uniformity of the first and second pins 50, 60.

In addition, the design of the width of the contact portion between the first tab set 320 and the first transfer portion 52 avoids the increase of the manufacturing cost of the first tab set 320 due to the overlong length of the first tab set 320. Meanwhile, the design of the width of the contact portion between the second tab set 330 and the second adapting portion 62 avoids the increase of the manufacturing cost of the second tab set 330 due to the overlong length of the second tab set 330.

In this embodiment, two first tab sets 320 expose a portion of the first adapting portion 52. The two second tab sets 330 expose a portion of the second adapter 62.

It should be noted that, along the X-axis direction, the two battery cell bodies 310 are arranged in parallel, and the opposite surfaces of the two battery cell bodies 310 are the same side. The surface of the first end tab a, which is farthest from the same side surface, before pre-welding is a first outer surface 321, the partial surface of the first end tab a, which is farthest from the same side surface, after pre-welding is a first outer side surface 3262 of the first tab set 320, the linear distance from the position of the first outer surface 321 to the position of the first outer side surface 3262 of the first intermediate section 326 is S1, and the linear distance S1 is smaller than the length of the first end tab a. It can be understood that the first end tab a furthest from the same side before pre-welding falls down and is welded with the other first tabs, and the distance from the position of the first end tab a before pre-welding to the position of the first end tab a after pre-welding is smaller than the length of the first end tab a, so that the length of the first end tab a can meet the requirement of forming the first middle section 326 of the first tab group 320 by welding with the other first tabs, thereby avoiding the situation that the current flowing through the formed first tab group 320 and the first pins 50 is inconsistent due to inconsistent lengths of a plurality of first tabs, and ensuring that a plurality of first tabs forming one first tab group 320 can be welded and combined and electrically conducted with the first pins 50.

Meanwhile, along the X-axis direction, the surface of the second end tab b furthest from the same side before pre-welding is the second outer surface 331, the partial surface of the second end tab b furthest from the same side after pre-welding is the second outer side surface 3362 of the second tab group 330, the linear distance from the position of the second outer surface 331 to the position of the second outer side surface 3362 of the second intermediate section 336 is S3, and the linear distance S3 is smaller than the length of the second end tab b. It can be understood that the second end tab b furthest from the same side before pre-welding falls down and is welded with the other second tabs, and the distance from the position of the second end tab b before pre-welding to the position of the second end tab b welded with the other second tabs after pre-welding is smaller than the length of the second end tab b, so that the length of the second end tab b can meet the requirement of forming the second intermediate section 336 of the second tab group 330 by welding with the other second tabs, thereby avoiding the condition that the current overcurrent of the formed second tab group 330 and the second pin 60 is inconsistent due to inconsistent lengths of a plurality of second tabs, and ensuring that a plurality of second tabs forming one second tab group 330 can be welded and combined and electrically conducted with the second pin 60.

It can be appreciated that the condition that the linear distance S1 is smaller than the length of the first end tab a is satisfied, and the condition that the linear distance S3 is smaller than the length of the second end tab b is satisfied, so that the current flowing through the first tab set 320 and the first pin 50 and the current flowing through the second tab set 330 and the second pin 60 are consistent, which is beneficial to the service lives of the first pin 50 and the second pin 60 to be consistent, and further to the consistency of the energy storage device 1000.

In this embodiment, since the first lead 50 is made of aluminum and the second lead 60 is made of copper, the first tab set 320 is matched with the first lead 50, the second tab set 330 is matched with the second lead 60, the material of the first tab set 320 is the same as that of the first lead 50, and the material of the second tab set 330 is the same as that of the second lead 60. However, copper has a higher conductivity than aluminum and a lower heat generation coefficient than aluminum, and thus, the conductive properties of the first pin 50 and the second pin 60 have a difference. The dimensions of the first and second pins 50 and 60 are designed to be unequal, i.e., the dimensions of the first and second switching portions 52 and 62 are unequal, and the dimensions of the first and second connection portions 51 and 61 are unequal to reduce the difference in the conductive properties of the first and second pins 50 and 60.

Referring to fig. 8 and 9, fig. 8 is a side view of a portion of the structure of the energy storage device shown in fig. 2, and fig. 9 is a schematic cross-sectional view of a portion of the structure of the energy storage device shown in fig. 8. The dashed line in fig. 8 indicates the boundary line between the first ultrasonic welding region and the first laser welding region. The dashed line in fig. 9 illustrates the boundary line of the second ultrasonic bonding region and the second laser bonding region. The housing is not illustrated in both fig. 8 and 9.

The first tab set 320 further includes a first ultrasonic welding region 327 and a first laser welding region 328. The first ultrasonic bond pad 327 and the first laser bond pad 328 are both located at the first attachment segment 325. The first ultrasonic welding region 327 is a region where a plurality of first tabs are ultrasonically welded. The first laser welding area 328 is an area where the first attachment section 325 and the first connecting portion 52 are laser welded. The first laser land 328 is located entirely within the first ultrasonic land 327. I.e., the orthographic projection of the first laser land 328 onto the first attachment section 325 is entirely within the first ultrasonic land 327. The first laser land 328 completely covers the first transfer portion 52. The shape of the first ultrasonic welding region 327 may be, but is not limited to, an elongated rectangle, an oval, etc. The shape of the first laser land 328 may be, but is not limited to, an elongated rectangle, an oval, etc. In this embodiment, the number of the first ultrasonic welding areas 327 is four, and every two first ultrasonic welding areas 327 are located in one first tab set 320. The two first ultrasonic welding areas 327 of the first tab group 320 are spaced along the Z-axis direction. The number of first laser lands 328 is two. Each of the first laser lands 328 is located in one of the first tab sets 320. The first laser land 328 is adjacent to the lower plastic 20. The first ultrasonic welding area 327 and the first laser welding area 328 are both rectangular.

The first ultrasonic welding region 327 has two first long sides 3271 and two first wide sides 3272. The two first long sides 3271 are disposed opposite to each other in the width direction (i.e., X-axis direction) of the first ultrasonic welding region 327. The two first broadsides 3272 are disposed opposite to each other along the length direction (i.e., the Z-axis direction) of the first ultrasonic welding region 327. Two first long sides 3271 are connected to two first wide sides 3272.

The first laser land 328 has two first short sides 3281 and two first narrow sides 3282. The two first short sides 3281 are disposed opposite to each other in the width direction (i.e., X-axis direction) of the first laser land 328. The two first narrow sides 3282 are disposed opposite each other along the length direction (i.e., the Z-axis direction) of the first laser land 328. The two first short sides 3281 are connected to the two first narrow sides 3282.

In this embodiment, the ratio of the area of the first ultrasonic welding region 327 to the area of the first laser welding region 328 is greater than or equal to 0.06 and less than or equal to 0.44. Wherein a pitch M1 of one first long side 3271 of the first ultrasonic land 327 and a first short side 3281 of the first laser land 328 adjacent to the first long side 3271 is greater than or equal to 2mm and less than or equal to 5mm. Meanwhile, a pitch N1 of one first broad side 3272 of the first ultrasonic land 327 and a first narrow side 3282 of the first laser land 328 adjacent to the first broad side 3272 is greater than or equal to 1mm and less than or equal to 2mm. It can be appreciated that the area of the first laser welding area 328 is smaller than that of the first ultrasonic welding area 327, so that the laser energy generated when the first attachment section 325 and the first converting portion 52 are welded by laser is prevented from being incident to the first outer side 3262, thereby preventing the laser energy from being reflected by a smooth surface, reducing the waste of the laser energy, and ensuring the welding effect when the first tab group 320 and the first pin 50 are welded by laser.

Referring to fig. 10 and 11, fig. 10 is a side view of a portion of the structure of the energy storage device shown in fig. 2 at another angle, and fig. 11 is a schematic cross-sectional view of a portion of the structure of the energy storage device shown in fig. 10 at another angle. The housing is not shown in fig. 10 and 11.

The second tab set 330 also includes a second ultrasonic bonding region 337 and a second laser bonding region 338. The second ultrasonic bond pad 337 and the second laser bond pad 338 are both located at the second attachment section 335. The second ultrasonic bonding region 337 is a region where a plurality of second tabs are ultrasonically bonded. The second laser welding area 338 is an area where the second attachment section 335 and the second adapting portion 62 are laser welded. The second laser land 338 is located entirely within the second ultrasonic land 337. I.e., the orthographic projection of the second laser land 338 on the second attachment section 335 is entirely within the second ultrasonic land 337. The second laser welding area 338 completely covers the second transfer portion 62. The shape of the second ultrasonic bonding region 337 may be, but is not limited to, a rectangular bar shape, an oval shape, or the like. The shape of the second laser land 338 may be, but is not limited to, an elongated rectangle, oval, etc. In this embodiment, the number of the second ultrasonic welding areas 337 is four, and every two second ultrasonic welding areas 337 are located in one second tab group 330. Two second ultrasonic bonding areas 337 located at one second tab group 330 are spaced apart in the Z-axis direction. The number of second laser lands 338 is two. Each second laser land 338 is located in one of the second tab sets 330. The second laser welding area 338 is adjacent to the lower plastic 20. The second ultrasonic pad 337 and the second laser pad 338 are each elongated rectangular.

The second ultrasonic bonding region 337 has two second long sides 3371 and two second wide sides 3372. The two second long sides 3371 are disposed opposite to each other in the width direction (i.e., X-axis direction) of the second ultrasonic welding region 337. The two second broad sides 3372 are disposed opposite to each other along the length direction (i.e., Z-axis direction) of the second ultrasonic welding region 337. Two second long sides 3371 are connected to two second wide sides 3372.

The second laser land 338 has two second short sides 3381 and two second narrow sides 3382. The two second short sides 3381 are disposed opposite to each other in the width direction (i.e., X-axis direction) of the second laser land 338. The two second narrow sides 3382 are disposed opposite to each other along the length direction (i.e., the Z-axis direction) of the second laser land 338. The two second short sides 3381 are connected to the two second narrow sides 3382.

In the present embodiment, the ratio of the area of the second ultrasonic welding region 337 to the area of the second laser welding region 338 is greater than or equal to 0.06 and less than or equal to 0.44. Wherein a pitch M2 of one second long side 3371 of the second ultrasonic bonding region 337 and a second short side 3381 of the second laser bonding region 338 adjacent to the second long side 3371 is greater than or equal to 2mm and less than or equal to 5mm. Meanwhile, a pitch N2 of one second broad side 3372 of the second ultrasonic bonding region 337 and a second narrow side 3382 of the second laser bonding region 338 adjacent to the second broad side 3372 is 1mm or more and 2mm or less. It can be appreciated that the area of the second laser welding area 338 is smaller than the area of the second ultrasonic welding area 337, so that the incidence of the laser energy generated when the second attachment section 335 and the second adapting portion 62 are subjected to laser welding to the second outer side surface 3362 is avoided, the reflection of the laser energy by the smooth surface is avoided, the waste of the laser energy is reduced, and the welding effect of the second tab set 330 and the second pin 60 during laser welding is ensured.

Referring to fig. 3, the first pole 30, the second pole 40, the first pin 50, the second pin 60, and the lower plastic 20 are all mounted on the end cap 10 together to form an end cap assembly 100. Wherein, along the Z-axis direction, the upper surface 21 of the lower plastic 20 is connected to the bottom surface 12 of the end cap 10. The first and second connection portions 51 and 61 are connected to the lower surface 22 of the lower plastic 20. The first and second adapter portions 52, 62 each extend away from the lower plastic 20.

Along the Z-axis direction, the first through hole 13 of the end cover 10, the first post through hole 23 of the lower plastic 20 and the first through hole 511 of the first connection portion 51 are coaxially arranged, and the first post 30 is arranged through the first through hole 13, the first post through hole 23 and the first through hole 511 and welded with the hole wall of the first through hole 511, so as to realize electrical conduction between the first post 30 and the first pin 50. Along the Z-axis direction, the second through hole 14 of the end cover 10, the second post through hole 24 of the lower plastic 20 and the second through hole 611 of the second connecting portion 61 are coaxially arranged, and the second post 40 is disposed through the second through hole 14, the second post through hole 24 and the second through hole 611 and welded with the hole wall of the second through hole 611, so as to realize electrical conduction between the second post 40 and the second pin 60. The first and second poles 30 and 40 are insulated and sealed from the end cap 10 by an insulating member (not shown), not only preventing the first and second poles 30 and 40 from being respectively shorted to the end cap 10, but also preventing electrolyte inside the energy storage device 1000 from flowing out of the energy storage device 1000.

The end cap assembly 100 is mounted to the battery cell 300. The lower surface 22 of the lower plastic 20 faces the cell 300. Along the Z-axis direction, the first connection portion 51 and the second connection portion 61 are disposed at intervals from the battery cell body 310, so as to avoid short circuit caused by connection of the first connection portion 51 and the second connection portion 61 with the battery cell body 310. The first switching part 52 is overlapped with the first tab set 320 and welded by a laser welding manner, so as to realize the electrical conduction between the first pin 50 and the first tab set 320, thereby realizing the electrical conduction between the battery core 300 and the first pole 30. The second adapting portion 62 is overlapped with the second tab set 330 and welded by means of laser welding, so as to realize electrical conduction between the first pin 50 and the first tab set 320, thereby realizing electrical conduction between the battery cell 300 and the second post 40.

The end cap assembly 100 and the battery 300 are both installed in the case 200, and the edge of the end cap 10 is connected with the edge of the opening 201 of the case 200 by welding or the like to seal the energy storage device 1000.

In the related art, since the material of the positive electrode pin and the material of the negative electrode pin are different, the conductive properties of the positive electrode pin and the negative electrode pin have differences. When the sizes of the positive electrode pin and the negative electrode pin are set to be the same and the sizes of the positive electrode tab and the negative electrode tab are also set to be the same, namely, the contact area of the positive electrode tab to the positive electrode pin is equal to the contact area of the negative electrode tab to the negative electrode pin, therefore, the current flowing capacity of the negative electrode pin and the current flowing capacity of the positive electrode pin are different. For example, in the case where both the positive electrode pin and the negative electrode pin satisfy the current flowing, the negative electrode pin may have a problem of excessive materials, thereby reducing the material utilization rate of the negative electrode pin, which is not beneficial to the consistency of the energy storage device 1000. Or under the condition that the current flowing through the negative electrode pin is just satisfied, the positive electrode pin with the same size as the negative electrode pin can bear higher heat when the current flows through the negative electrode pin, and the service life of the positive electrode pin is generally lower than that of the negative electrode pin along with repeated charging and discharging of the battery cell 300, so that the consistency of the energy storage device 1000 is reduced.

In the embodiment of the present application, the first lead 50 and the second lead 60 have different sizes, and the first tab set 320 and the second tab set 330 also have different sizes, so that the widths of the contact portions of the first tab set 320 and the first lead 50 are different under the requirement of meeting the current flowing requirement of the first tab set 320 and the first lead 50. Meanwhile, under the condition that the requirements of the second lug group 330 on the current overcurrent of the second pin 60 are met, the widths of the contact parts of the second lug group 330 and the second pin 60 are also different, the problem that the current overcurrent capacity of the first pin 50 and the second pin 60 is different is solved, the service lives of the first pin 50 and the second pin 60 tend to be consistent, the problem that the material utilization rate of the first pin 50 and the second pin 60 is low is solved, the consistency of the first pin 50 and the second pin 60 is facilitated, and the consistency of the energy storage device 1000 is further facilitated.

The above is only a part of examples and embodiments of the present application, and the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are covered in the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims (10)

1. An energy storage device, comprising: a housing, the housing comprising an opening; A battery cell, the battery cell is installed in the shell, the battery cell comprises a battery cell body, a first pole lug group and a second pole lug group, the battery cell body comprises a first side surface and a second side surface, the first side surface and the second side surface are arranged opposite to each other along the length direction of the battery cell body, the first pole lug group is led out from the first side surface, and the second pole lug group is led out from the second side surface; An end cap assembly, the end cap assembly is mounted at one end of the battery cell and sealed at the opening, the end cap assembly includes a first pin and a second pin, the first pin includes a first transition portion, the first transition portion is overlapped on the first side, the first tab group covers and connects the first transition portion, and the first tab group and the first transition portion have an overlapped portion, the second pin includes a second transition portion, the second transition portion is overlapped on the second side, the second tab group covers and connects the second transition portion, and the second tab group and the second transition portion have an overlapped portion, and the size of the first transition portion is not equal to the size of the second transition portion; The first tab group includes a first outer side surface, the first outer side surface faces away from the first transition portion, a straight-line distance between the first outer side surface and the central axis of the battery cell in the length direction is D1, and a width of a portion where the first tab group and the first transition portion overlap in the width direction of the battery cell is D2, wherein a ratio of D2 to D1 is greater than or equal to 5/7 and less than or equal to 6/7; The second pole lug group includes a second outer side surface, the second outer side surface is opposite to the second transition portion, the straight-line distance between the second outer side surface and the central axis in the length direction of the battery cell is D3, and the width of the overlapping portion of the second pole lug group and the second transition portion in the width direction of the battery cell is D4, wherein the ratio of D4 to D3 is greater than or equal to 4/7 and less than or equal to 5/7. 2. The energy storage device according to claim 1, characterized in that the first pole lug group comprises a plurality of first pole lugs, the plurality of first pole lugs are stacked along the thickness direction of the first pole lug group, the plurality of first pole lugs are pre-welded by ultrasonic welding and cut to form the first pole lug group, and the second pole lug group comprises a plurality of second pole lugs, the plurality of second pole lugs are stacked along the thickness direction of the second pole lug group, the plurality of second pole lugs are pre-welded by ultrasonic welding and cut to form the second pole lug group; When the first electrode tab group and the second electrode tab group are under the same welding power, the number of the first electrode tabs and the number of the second electrode tabs are not equal. 3. The energy storage device according to claim 2, characterized in that the first pole lug comprises a first end pole lug, the surface of the first end pole lug before pre-welding is a first outer surface, a part of the surface of the first end pole lug after pre-welding is the first outer side surface of the first pole lug group, and a straight-line distance from the position of the first outer surface to the position of the first outer side surface is less than the length of the first end pole lug; The second pole lug includes a second end pole lug, the surface of the second end pole lug before pre-welding is the second outer surface, and a portion of the surface of the second end pole lug after pre-welding is the second outer side surface of the second pole lug group, and a straight-line distance from the position of the second outer surface to the position of the second outer side surface is less than the length of the second end pole lug. 4. The energy storage device according to claim 1, characterized in that the number of the first tab groups is two, the two first tab groups are respectively located on opposite sides of the width direction of the first transition portion and are bent toward the first transition portion, each of the first tab groups includes a first attachment section, the two first attachment sections extend relatively along the width direction of the first transition portion and are both attached to the surface of the first transition portion facing away from the first side surface, and the first attachment section is connected to the first transition portion by laser welding; There are two second pole lug groups, the two second pole lug groups are respectively located on opposite sides of the width direction of the second transition portion and are bent toward the second transition portion, each second pole lug group includes a second attachment section, the two second attachment sections extend toward each other along the width direction of the second transition portion and are both attached to the surface of the second transition portion facing away from the second side surface, and the second attachment section is connected to the second transition portion by laser welding. 5. The energy storage device according to claim 4, characterized in that each of the first tab groups further comprises a first lead-out section and a first middle section, the first lead-out section is connected to the first side surface and is electrically conductive with the battery cell body, the first middle section is connected to the first lead-out section and is connected to the first attachment section at an angle, the first middle section has the first outer side surface, the first transition portion comprises a first transition inner surface, the first transition inner surface faces the first lead-out section and is spaced from the first side surface; Each of the first electrode tab groups also includes a second lead-out section and a second middle section, the second lead-out section is connected to the second side surface and is electrically conductive with the battery cell body, the second middle section is connected to the second lead-out section and is connected at an angle to the second attachment section, the second middle section has the second outer side surface, and the second transition portion includes a second transition inner surface, the second transition inner surface faces the second lead-out section and is spaced from the second side surface. 6. The energy storage device according to claim 4, characterized in that the thickness of the first attachment section is greater than or equal to 1 mm and less than or equal to 2 mm; The thickness of the second attachment section is greater than or equal to 1 mm and less than or equal to 2 mm. 7. The energy storage device according to claim 4, characterized in that the first tab group includes a first ultrasonic welding area and a first laser welding area, the first ultrasonic welding area and the first laser welding area are both located in the first attachment section, the first laser welding area is completely located in the first ultrasonic welding area, the ratio of the area of the first laser welding area to the area of the first ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the first laser welding area completely covers the first transition portion; The second tab group includes a second ultrasonic welding area and a second laser welding area, the second ultrasonic welding area and the second laser welding area are both located in the second attachment section, the second laser welding area is completely located in the second ultrasonic welding area, the ratio of the area of the second laser welding area to the area of the second ultrasonic welding area is greater than or equal to 0.06 and less than or equal to 0.44, and the second laser welding area completely covers the second transition portion. 8. The energy storage device according to claim 7, characterized in that the first laser welding area includes a first short side and a first narrow side, the first ultrasonic welding area includes a first long side and a first wide side, the first long side is parallel to the first short side, and the spacing between the first long side and the adjacent first short side is greater than or equal to 2 mm and less than or equal to 5 mm, the first wide side is parallel to the first narrow side, and the spacing between the first wide side and the adjacent first narrow side is greater than or equal to 1 mm and less than or equal to 2 mm; The second laser welding area includes a second short side and a second narrow side, the second ultrasonic welding area includes a second long side and a second wide side, the second long side is parallel to the second short side, and the spacing between the second long side and the adjacent second short side is greater than or equal to 2 mm and less than or equal to 5 mm, the second wide side is parallel to the second narrow side, and the spacing between the second wide side and the adjacent second narrow side is greater than or equal to 1 mm and less than or equal to 2 mm. 9. The energy storage device according to any one of claims 1 to 8, characterized in that the length of the first tab group is greater than or equal to 25.5 mm and less than or equal to 29.5 mm; The length of the second tab group is greater than or equal to 22 mm and less than or equal to 26 mm. 10. An electrical equipment, characterized in that it comprises the energy storage device according to any one of claims 1 to 9, and the energy storage device supplies power to the electrical equipment.