CN113948711A

CN113948711A - Electrochemical device, battery pack, and electronic device

Info

Publication number: CN113948711A
Application number: CN202111201505.0A
Authority: CN
Inventors: 孟春雷; 陶涛
Original assignee: Dongguan Poweramp Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2021-10-15
Filing date: 2021-10-15
Publication date: 2022-01-18

Abstract

An electrochemical device, a battery pack, and an electronic device are disclosed. The electrochemical device includes an electrode assembly and a packaging bag, the electrode assembly being disposed in the packaging bag. The electrode assembly includes a first electrode piece and a first conductive member, the first electrode piece including a first current collector and a first active material layer. The first current collector includes, in a first direction, a first portion at which the first active material layer is disposed and a second portion including the first shaping region. The first conductive member extends out of the package bag in a first direction and includes a first connection surface facing the electrode assembly, the first connection surface being connected to the first shaping region. The first shaping area is arranged on the first current collector, and the first connecting surface faces the second part, so that the first shaping area is connected with the first connecting surface, the risk of short circuit caused by reversely inserting the first shaping area and the first conductive piece into the pole piece is reduced, and the use safety is improved.

Description

Electrochemical device, battery pack, and electronic device

Technical Field

The present application relates to the field of energy storage technologies, and in particular, to an electrochemical device, a battery pack, and an electronic device.

Background

Lithium ion batteries are widely used in products such as mobile phones, notebook computers, tablet computers, electric vehicles, electric tools and the like because of their excellent properties such as high energy density, long cycle performance, and low pollution. With the development of the market and the improvement of science and technology, the requirements on the energy density and the charge-discharge rate of the lithium ion battery are higher and higher.

At present, the rate performance of the battery is improved and the temperature rise is reduced by a full-tab design or a multi-tab design. But full-tab or multi-tab batteries present the risk of short circuits.

Disclosure of Invention

In view of the above, it is desirable to provide an electrochemical device, a battery pack and an electronic device, which can reduce the risk of short circuits.

An embodiment of the present application provides an electrochemical device including an electrode assembly and a packaging bag, the electrode assembly being disposed in the packaging bag. The electrode assembly includes a first electrode piece and a first conductive member, the first electrode piece including a first current collector and a first active material layer. The first current collector includes, in a first direction, a first portion at which the first active material layer is disposed and a second portion including the first shaping region. The first conductive member extends out of the package bag in a first direction and includes a first connection surface facing the electrode assembly, the first connection surface being connected to the first shaping region.

The embodiment of the application comprises the following technical effects: this application is through setting up first plastic district on first mass flow body to through first connection face towards the setting of second part, make first plastic district connect first connection face, reduce first plastic district and first electrically conductive piece and insert the risk that causes the short circuit in the pole piece upside down, promote electrochemical device's safety in utilization.

In some possible implementations, the length of the second portion is greater than or equal to 70% of the length of the first current collector in a second direction perpendicular to the first direction.

In some possible implementations, the length of the second portion is equal to the length of the first current collector along the second direction.

In some possible implementations, the first shaping region includes a first tab extending outward in a first direction and connected to the first connection face.

In some possible implementations, the electrode assembly is wound into a roll.

In some possible implementations, a second conductive member, a second pole piece, and a separation film are further included. The isolating film is arranged between the first pole piece and the second pole piece. The second pole piece comprises a second current collector and a second active material layer, and the second current collector comprises a third portion and a fourth portion. The second active material layer is provided on the third portion. The fourth section includes a second shaping region. The second conductive member protrudes from the package bag and includes a second connection surface facing the electrode assembly. The second connecting surface is connected with the second reshaping area. The fourth portion is located on a side of the second connection face facing the electrode assembly.

The embodiment of the application comprises the following technical effects: the second shaping area is arranged on the second current collector, and the second connecting surface is arranged towards the fourth part, so that the second shaping area is connected with the second connecting surface, the risk of short circuit caused by reversely inserting the second shaping area and the second conductive piece into the pole piece is reduced, and the use safety of the electrochemical device is improved.

In some possible implementation manners, the width of the first shaping region extending out of the isolation film along the first direction is d3, d3 is greater than or equal to 0.5mm and less than or equal to 5mm, and the thickness of the first shaping region along the thickness direction of the first pole piece is d4, and d4 is greater than or equal to 0.2mm and less than or equal to 5 mm.

In some possible implementations, the package includes a body portion for housing the motor assembly, and a projection of the first shaping region is spaced apart from a projection of the body portion along the first direction.

The embodiment of the application comprises the following technical effects: the risk that the first shaping area pierces the packaging bag and the electrolyte corrodes the metal layer of the packaging bag after the packaging bag is pierced is reduced.

In some possible implementations, the packaging bag includes a first layer, a metal layer, and a second layer disposed in a stacked arrangement, the metal layer being disposed between the first layer and the second layer, the first layer including a polymer and being disposed on a surface of the metal layer facing the electrode assembly.

In some possible implementations, the first electrically conductive member includes a first structural member and a second structural member. The first structural member has a first connecting surface. The second structural member is connected with the first structural member and extends out of the packaging bag. The second structural part is provided with a first colloid for connecting the packaging bag.

The embodiment of the application comprises the following technical effects: the welding area between the first structural part and the first shaping area is increased through the first structural part and the second structural part, high-rate charge and discharge are achieved, and temperature rise is reduced.

In some possible implementations, the number of the second portions is multiple, and the multiple second portions are spaced apart along the extending direction of the first current collector.

In some possible implementations, a second pole piece and a separation film are further included. The isolating film is arranged between the first pole piece and the second pole piece. The first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

In some possible implementations, the second electrode plate includes a second current collector and a second active material layer disposed on the second current collector, a first recess is disposed in a middle of the second active material layer in the second direction, the second current collector is exposed from the first recess, a second electrode tab is disposed in the first recess, the second electrode tab extends in the third direction and exceeds the second current collector, and the first direction is opposite to the third direction.

The embodiment of the application comprises the following technical effects: through setting up single second utmost point ear, the electron route is short, with the big multiplying power structure phase-match of the first utmost point ear of first pole piece, not only promotes big multiplying power charge-discharge performance, can improve the problem that electrolyte soaks badly moreover.

The present application also provides a battery comprising the electrochemical device of any of the above embodiments.

The present application also provides an electronic device including the battery pack of any of the above embodiments.

Drawings

Fig. 1 is a schematic structural view of an electrochemical device in some embodiments.

Fig. 2 is a cross-sectional view of the electrochemical device shown in fig. 1 taken along line II-II with the packaging bag removed.

FIG. 3 is a cross-sectional view of the package taken along line II-I I in some embodiments.

Fig. 4 is a schematic diagram of the first pole piece after being unfolded in some embodiments.

Fig. 5 is a schematic diagram of the second pole piece after being unfolded in some embodiments.

Fig. 6 is a schematic structural diagram of the second portion without the first shaping region in some embodiments.

Fig. 7 is a schematic structural diagram of the first shaping region and the second shaping region in some embodiments.

Fig. 8 is a schematic structural diagram of the second pole piece after being unfolded in other embodiments.

Fig. 9 is a schematic structural diagram of an electronic device in some embodiments.

Description of the main elements

Electrochemical device 100

Packaging bag 10

Body part 11

Edge seal 12

First layer 13

Metal layer 14

Second layer 15

Electrode assembly 30

First region 30a

First pole piece 31

First current collector 311

First active material layer 312

First section 3111

Second section 3112

First shaping region 311a

Second pole piece 32

Second current collector 321

Second active material layer 322

First concave portion 3221

Second tab 322a

Third part 3211

Fourth portion 3212

Second shaping region 321a

First conductive member 50

First structural member 51

First connection face 511

Second structural member 52

First colloid 521

Second conductive member 70

Second connection surface 71

Second colloid 72

Battery pack 200

Electronic device 300

First direction X

Second direction Y

The following detailed description will further illustrate the present application in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present application are described in detail below clearly, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Hereinafter, embodiments of the present application will be described in detail. This application may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and detailed, and will fully convey the scope of the disclosure to those skilled in the art.

In addition, the dimensions or thicknesses of various components, layers, and/or layers may be exaggerated in the figures for clarity and conciseness. Like numbers refer to like elements throughout. As used herein, the term "and/or", "and/or" includes any and all combinations of one or more of the associated listed items. In addition, it should be understood that when element a is referred to as being "connected" element B, element a may be directly connected to element B, or intermediate element C may be present and element a and element B may be indirectly connected to each other.

Further, the use of "may" when describing embodiments of the present application refers to "one or more embodiments of the present application.

As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, values, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, values, steps, operations, elements, components, and/or groups thereof.

Spatially relative terms, such as "upper" and the like, may be used herein for convenience in description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device or apparatus in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "upper" other elements or features would then be oriented "below" or "lower" the other elements or features. Thus, the exemplary term "up" can include both an orientation of above and below. It will be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

Embodiments of the present application provide an electrochemical device including an electrode assembly and a packaging bag. The electrode assembly is arranged in the packaging bag. The electrode assembly includes a first pole piece and a first electrically conductive member. The first pole piece comprises a first current collector and a first active material layer. Along the first direction, the first current collector includes a first portion and a second portion. A first active material layer is disposed on the first portion. The second portion includes a first shaping region. The first conductive member extends out of the pouch in a first direction and includes a first connection surface facing the electrode assembly. The first connecting surface is connected with the first shaping region.

This application is through setting up first plastic district on first mass flow body to through first connection face towards the setting of second part, make first plastic district connect first connection face, reduce first plastic district and first electrically conductive piece and insert the risk that causes the short circuit in the pole piece upside down, promote electrochemical device's safety in utilization.

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings.

Referring to fig. 1 and 2, an embodiment of the present application provides an electrochemical device 100 including a package 10, an electrode assembly 30, a first conductive member 50, and a second conductive member 70. The electrode assembly 30 is disposed in the package bag 10 and includes a pole piece and a separator 33. The pole pieces include a first pole piece 31 and a second pole piece 32, and a separator 33 is disposed between the first pole piece 31 and the second pole piece 32. The separator 33 serves to prevent the first and

second pole pieces

31 and 32 from being in direct contact, thereby reducing the risk of a short circuit between the first and

second pole pieces

31 and 32. A first conductive member 50 is connected to the first pole piece 31 and extends partially out of the package 10 and a second conductive member 70 is connected to the second pole piece 32 and extends partially out of the package 10. The first and second

conductive members

50 and 70 are used to connect external electric devices, and the external electric devices are energy-transmitted through the first and second

conductive members

50 and 70.

In some embodiments, the packaging bag 10 may be a packaging bag packaged by a packaging film (e.g., an aluminum plastic film), i.e., the electrochemical device 100 is a pouch battery. The packaging bag 10 includes a body part 11 for receiving the electrode assembly 30 and a sealing edge 12 connected to the body part 11.

Referring to fig. 3, in some embodiments, the package 10 includes a first layer 13, a metal layer 14 and a second layer 15 stacked together, the metal layer 14 is disposed between the first layer 13 and the second layer 15, and the second layer 15 is disposed on an outermost layer of the package 10. The second layer 15 can be a nylon layer or a composite layer of polyester resin (PET) and nylon, and has the protection functions of preventing pollution, corrosion and external force damage. The metal layer 14 may comprise one of aluminum and steel to provide water resistance, barrier, and form the package 10. The first layer 13 is a heat seal layer and the first layer 13 may comprise a polymer, including one of polypropylene and polyethylene, for sealing the package 10 and for separating the metal layer from the electrode assembly 30, reducing the risk of electrolyte leakage from the package 10 and corroding the metal layer.

In some embodiments, the electrode assembly 30 is a wound structure, i.e., the first pole piece 31, the separator 33, and the second pole piece 32 are sequentially stacked and then wound to form the electrode assembly 30. In other embodiments, the electrode assembly 30 may also be a lamination structure in which the first pole piece 31, the separator 33, and the second pole piece 32 are sequentially laminated to form one electrode assembly unit, and a plurality of electrode assembly units are further laminated to form the electrode assembly 30. In some embodiments, the first pole piece 31 is a negative pole piece or a positive pole piece, and the second pole piece 32 is a pole piece with opposite polarity of the first pole piece 31.

Referring to fig. 2 and 4, the first pole piece 31 includes a first current collector 311 and a first active material layer 312 disposed on the first current collector 311. The first current collector 311 includes a first portion 3111 and a second portion 3112, the first portion 3111 and the second portion 3112 are arranged side by side along the first direction X, the first active material layer 312 is provided on the first portion 3111, and the second portion 3112 partially protrudes from the separation film 33. The second portion 3112 includes a first shaping region 311a, and the first conductive member 50 is connected to the first shaping region 311 a.

In some embodiments, the second section 3112 may be partially provided with the first shaping region 311a, or may be entirely provided with the first shaping region 311 a.

Referring to fig. 2 and 4, in some embodiments, the second electrode sheet 32 includes a second current collector 321 and a second active material layer 322 disposed on the second current collector 321. The second current collector 321 includes a third portion 3211 and a fourth portion 3212, the third portion 3211 and the fourth portion 3212 are arranged side by side along the first direction X, the second active material layer 322 is disposed on the third portion 3211, and a portion 3212 extends out of the isolation film 33. The fourth portion 3212 includes a second shaping region 321a, and the second conductive member 70 is connected to the second shaping region 321 a.

In some embodiments, the fourth portion 3212 may be partially disposed with the second shaping region 321a, or may be disposed with the second shaping region 321 a.

In some embodiments, the first current collector 311 may be, but is not limited to, a metal foil such as a copper foil or a nickel foil. The second current collector 321 may be, but is not limited to, a metal foil such as an aluminum foil or a nickel foil.

In some embodiments, when the electrode assembly 30 is a wound structure, the first direction X is a width direction of the first current collector 311 and a width direction of the second current collector 321; when the electrode assembly 30 is a laminated structure, the first direction X may be a width direction of the first current collector 311 and a width direction of the second current collector 321, and may also be a length direction of the first current collector 311 and a length direction of the second current collector 321. It is understood that, taking the first current collector 311 as an example, the "length direction" and the "width direction" of the first current collector 311 refer to two dimensions of the surface of the first current collector 311, respectively. Wherein the length direction refers to the direction of the major dimension (i.e., the direction of the larger dimension), and the width direction refers to the direction of the minor dimension (i.e., the direction of the smaller dimension). In general, the longitudinal direction is coincident with the coating direction of each material layer (e.g., first active material layer 312) during the processing of the pole piece, and also coincident with the winding direction of the pole piece during the manufacturing of the electrochemical device. And the width direction is perpendicular to the length direction.

In some embodiments, the second portion 3112 is continuously disposed along a second direction Y perpendicular to the first direction X, and a length of the second portion 3112 is equal to a length of the first current collector 311 along the second direction Y. Specifically, taking the electrode assembly 30 as an example of a wound structure, the first portion 3111 and the second portion 3112 are disposed along the width direction of the first current collector 311, the second portion 3112 is disposed continuously along the length direction of the first current collector 311, and the length of the second portion 3112 is equal to the length of the first current collector 311.

In some embodiments, the number of the second portions 3112 is plural, and the plural second portions 3112 are arranged at intervals along the extending direction of the first current collector 311, and the sum of the lengths of the plural second portions 3112 along the second direction Y is greater than or equal to 70% of the length of the first current collector. Specifically, taking the electrode assembly 30 as an example of a wound structure, the first portion 3111 and the plurality of second portions 3112 are disposed along a width direction of the first current collector 311, the plurality of second portions 3112 are disposed at intervals along a length direction of the first current collector 311, and a length of the plurality of second portions 3112 is greater than or equal to 70% of a length of the first current collector 311 along the length direction of the first current collector 311.

In some embodiments, when the second portion 3112 is continuously disposed along the second direction Y perpendicular to the first direction X, the length of the second portion 3112 is greater than or equal to 70% of the length of the first current collector along the second direction Y.

It is understood that the first portion 3111 and the second portion 3112 may also be disposed along a length direction of the first current collector 311.

Referring to fig. 6 and 7, the portion of the second portion 3112 extending out of the isolation film 33 is shaped to form a first shaping region 311a, and the portion of the fourth portion 3212 extending out of the isolation film 33 is shaped to form a second shaping region 321 a. Taking the second section 3112 as an example, the initial width of the second section 3112 in the first direction X is d1, and the initial width is the width of the second section 3112 before shaping. 5 mm. ltoreq. d 1. ltoreq.20 mm, for example, d1 may be any of 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19 mm. The second portion 3112 extends beyond the separating film 33 by a width d2, wherein d2 is greater than 0mm and less than or equal to 10 mm. For example, d2 is any one of 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, and 9 mm. Second portion 3112 is partially within isolation diaphragm 33 and partially extends beyond isolation diaphragm 33, reducing the area of second portion 3112 extending beyond isolation diaphragm 33 and reducing the risk of contact shorts.

Referring to fig. 2 and fig. 7, taking the first shaping region 311a as an example, the width d3 of the isolation film 33 extending from the first shaping region 311a along the first direction X is 0.5mm ≦ d3 ≦ 5mm, for example, d3 may be any one of 0.5mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, and 4.5 mm. Along the thickness direction of the first pole piece 31, the thickness of the first shaping region 311a is d4, and d4 is not less than 0.2mm and not more than 5 mm. For example, d4 may be any one of 0.5mm, 0.8mm, 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5 mm. Further, the width of the first shaping region 311a extending beyond the separation film 33 is 1.0mm to 3.0mm, for example, any one of 1.0mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, and 3.0 mm.

In some embodiments, taking the first shaping region 311a as an example, the first shaping region 311a is a hollow foil region where the first active material layer 312 is not disposed on the first current collector 311, and the first shaping region 311a is a region formed by deforming the second portion 3112 after the electrode assembly 30 is wound or laminated. The manner of deformation includes, but is not limited to, ultrasonic kneading or mechanical vibration kneading. By providing the first shaping region 311a, the distance in the longitudinal direction or the width direction of the electrode assembly 30 occupied by the void foil region is reduced, the ratio of the active material is increased, and the energy density of the electrochemical device 100 is increased. Further, the first shaping region 311a includes a first tab, and the first tab extends outward along the first direction X. Along a second direction Y perpendicular to the first direction X, the length of the first tab along the second direction Y is less than or equal to the length of the first current collector 311. It is understood that the first shaping region 311a may partially serve as the first tab, or may entirely serve as the first tab.

The first shaping region 311a and the second shaping region 321a have the same structure, and are not described herein.

It is understood that there may be a 0- ± 10% tolerance in the dimensions of first shaping region 311a and second shaping region 321 a.

Referring to fig. 1, 2 and 3, in some embodiments, the electrode assembly 30 has a first region 30a along the first direction X, and the first shaping region 311a is disposed in the first region 30 a. Along the first direction X, the projection of the first region 30a is located in the projection of the packaging bag 10, and the projection of the first shaping region 311a is separated from the projection of the main body 11 of the packaging bag 10, so that the first shaping region 311a is far away from the packaging bag 10, thereby reducing the risk that the first shaping region 311a pierces through the packaging bag 10 and the electrolyte corrodes the metal layer 14 of the packaging bag 10 after piercing through the packaging bag 10.

In some embodiments, first conductor 50 includes a first structural member 51 and a second structural member 52. The first junction member 51 has a first junction surface 511, the first junction surface 511 faces the electrode assembly 30, and the first junction surface 511 is connected to the first shaping region 311a, and the second portion 3112 is located on a side of the first junction surface 511 facing the electrode assembly 30. The second structural member 52 is connected to the first structural member 51 and extends out of the packaging bag 10, the second structural member 52 is provided with a first glue 521, and the first glue 521 is sealed with the packaging bag 10, for example, by hot pressing. The welding area between the first shaping region 311a and the first structural member 51 and the second structural member 52 is increased, so that high-rate charge and discharge are realized, and temperature rise is reduced. Further, the first structural member 51 is connected by laser welding or conductive adhesive bonding, so that the first connection surface 511 and the first shaping region 311a are electrically connected. In some embodiments, the first conductive member 50 is Y-shaped or L-shaped. It is understood that the shapes and sizes of the first structural member 51 and the second structural member 52 can be adjusted according to the first shaping region 311a to maximize the welding area with the first shaping region 311 a.

In some embodiments, the second conductive member 70 is provided with a second connection surface 71 facing the electrode assembly 30, and the second connection surface 71 connects the second shaping region 321 a. The second conductive member 70 is provided with a second colloid 72, and the second colloid 72 is sealed with the packaging bag 10, for example, by hot pressing. It is understood that the second conductive member 70 has the same structure as the first conductive member 50, and thus, the description thereof is omitted.

It is understood that the structure of the second conductive member 70 may have a tolerance of 0- ± 10% with the size of the first conductive member 50.

According to the electrochemical device, the first shaping area 311a is arranged on the first current collector 311, the first shaping area 311a is used as a first tab, bending of the first tab is reduced, the first connecting surface 511 is arranged towards the second part 3112 through the first connecting surface 511, the first tab is connected with the first connecting surface 511, the risk that the first shaping area 311a and the first conductive piece 50 are inserted into a pole piece in a reverse mode to cause short circuit is reduced, and the use safety of the electrochemical device is improved.

Referring to fig. 2, 4 and 5, another embodiment of the present application further provides an electrochemical device, which is different from the previous embodiments in that only one of the first pole piece 31 and the second pole piece 32 is provided with a shaping region, and the electrolyte enters the inside of the electrode assembly 30 through the side where the shaping region is not provided, so as to improve the problem of poor electrolyte infiltration. Specifically, taking the first pole piece 31 provided with the shaping region as an example, the first pole piece 31 includes a first current collector 311 and a first active material layer 312 disposed on the first current collector 311. The first current collector 311 includes a first portion 3111 and a second portion 3112, the first portion 3111 and the second portion 3112 are arranged side by side along the first direction X, and the first active material layer 312 is provided on the first portion 3111. The second section 3112 includes a first shaping region 311 a.

In some embodiments, the second electrode sheet 32 includes a second current collector 321 and a second active material layer 322 disposed on the second current collector 321. The second current collector 321 includes a third portion 3211 and a fourth portion 3212, the third portion 3211 and the fourth portion 3212 are arranged side by side along the first direction X, and the second active material layer 322 is disposed on the third portion 3211. The fourth portion 3212 serves as a second tab or a structure that is cut into a plurality of tabs.

Referring to fig. 8, in another embodiment, the second electrode sheet 32 includes a second current collector 321 and a second active material layer 322 disposed on the second current collector 321, a first concave portion 3221 is disposed in a middle position of the second active material layer 322 in the second direction Y, the second current collector 321 is exposed from the first concave portion 3221, the first concave portion 3221 is provided with a second electrode tab 322a, the second electrode tab 322a extends in the third direction and exceeds the second current collector 321, and the first direction is opposite to the third direction. The middle position of the second active material layer 322 in the second direction Y is a position of one-third to two-thirds of the second current collector 321 in the second direction Y.

Further, when the second current collector 321 is provided with the second tab 322a, the second tab 32 is a negative electrode tab, the first tab 31 is a positive electrode tab, and the first tab 31 is provided with a shaping area. The first current collector 311 is aluminum and the second current collector 321 is one of copper nickel plating, which has a current carrying capacity greater than aluminum. The first pole piece 31 is provided with the shaping area to reduce the risk of short circuit caused by inserting the pole lug and the first conductive piece 50 into the pole piece in an inverted mode, and the single second pole lug 322a is arranged, so that the electronic path is short and is matched with the high-rate structure of the first pole lug of the first pole piece 31, the high-rate charge and discharge performance is improved, if the high-rate charge and discharge temperature rise is low, and the problem of poor electrolyte infiltration can be solved.

The electrochemical device 100 of the present application includes all devices capable of electrochemical reactions. Specifically, the electrochemical device 100 includes all kinds of primary batteries, secondary batteries, fuel cells, solar cells, and capacitors (e.g., super capacitors). Alternatively, the electrochemical device 100 may be a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.

An embodiment of the present application also provides a battery pack 200, the battery pack 200 including at least one electrochemical device 100.

Referring to fig. 9, an electronic device 300 is further provided in an embodiment of the present application, where the electronic device 300 includes a battery pack 200. The battery pack 200 of the present application is suitable for use in electronic devices 300 in various fields. In one embodiment, the electronic device 300 of the present application may be, but is not limited to, an unmanned aerial vehicle, a notebook computer, a pen-input computer, a mobile computer, an electronic book player, a cellular phone, a portable facsimile machine, a portable copier, a portable printer, a head-mounted stereo headset, a video recorder, a liquid crystal television, a portable cleaner, a portable CD player, a mini-disc, a transceiver, an electronic organizer, a calculator, a portable recorder, a radio, a lighting fixture, a toy, a game machine, a power tool, a flashlight, a camera, a large-sized household battery, a lithium ion capacitor, and the like.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present application and not for limiting, and those skilled in the art should understand that the technical solutions of the present application can be modified or substituted with equivalents without departing from the scope of the present disclosure.

Claims

1. An electrochemical device comprising an electrode assembly and a packaging bag, wherein the electrode assembly is disposed in the packaging bag, the electrode assembly comprising:

the first pole piece comprises a first current collector and a first active material layer, the first current collector comprises a first part and a second part along a first direction, the first active material layer is arranged on the first part, and the second part comprises a first shaping area; and

a first conductive member extending out of the package bag in the first direction and including a first connection surface facing the electrode assembly, the first connection surface being connected to the first shaping region;

the second portion is located on a side of the first connection face facing the electrode assembly.

2. The electrochemical device of claim 1, wherein a length of the second portion is greater than or equal to 70% of a length of the first current collector in a second direction perpendicular to the first direction.

3. The electrochemical device of claim 2, wherein a length of the second portion is equal to a length of the first current collector along the second direction.

4. The electrochemical device of claim 1 wherein said first shaping region includes a first tab extending outwardly in said first direction and connecting to said first connection surface.

5. The electrochemical device of claim 1, wherein said electrode assembly is wound.

6. The electrochemical device of claim 1, further comprising:

a second conductive member;

a second pole piece; and

the isolating film is arranged between the first pole piece and the second pole piece;

the second pole piece comprises a second current collector and a second active material layer, the second current collector comprises a third part and a fourth part along the first direction, the second active material layer is arranged on the third part, and the fourth part comprises a second shaping area;

the second conductive member extends out of the package bag and includes a second connection surface facing the electrode assembly, the second connection surface being connected to the second shaping region;

the fourth portion is located on a side of the second connection face facing the electrode assembly.

7. The electrochemical device as claimed in claim 6, wherein the first shaping region protrudes beyond the separator by a width d3 of 0.5mm or more and d3 or more and 5mm or less in the first direction, and the first shaping region has a thickness d4 of 0.2mm or more and d4 or more and 5mm or less in the thickness direction of the first pole piece.

8. The electrochemical device of claim 1, wherein said package includes a body portion for receiving said electrode assembly, a projection of said first shaping region being spaced from a projection of said body portion in said first direction.

9. The electrochemical device according to claim 1, wherein the packaging bag comprises a first layer, a metal layer and a second layer which are arranged in a stacked manner, the metal layer being provided between the first layer and the second layer, the first layer comprising a polymer and being provided on a surface of the metal layer facing the electrode assembly.

10. The electrochemical device of claim 1, wherein said first electrically conductive member comprises:

a first structural member having the first connection face;

the second structure is connected the first structure stretches out the wrapping bag, the second structure is equipped with first colloid, is used for connecting the wrapping bag.

11. The electrochemical device according to claim 1, wherein the second portion is provided in plural numbers, and the plural second portions are provided at intervals along an extending direction of the first current collector.

12. The electrochemical device of claim 2, further comprising:

a second pole piece; and

the first pole piece is a positive pole piece, and the second pole piece is a negative pole piece.

13. The electrochemical device according to claim 12, wherein the second electrode sheet includes a second current collector and a second active material layer disposed on the second current collector, the second active material layer is provided with a first recess at a middle position in the second direction, the first recess exposes the second current collector, the first recess is provided with a second tab, the second tab extends in a third direction and beyond the second current collector, and the first direction is opposite to the third direction.

14. A battery comprising at least one electrochemical device according to any one of claims 1 to 13.

15. An electronic device characterized by comprising the battery pack as set forth in claim 14.