CN118553978A - Secondary battery system - Google Patents

Abstract

The present invention provides a secondary battery system, which relates to the technical field of new energy batteries. The battery pack includes a shell and a plurality of groups of bipolar batteries contained in the shell, wherein the plurality of groups of bipolar batteries are stacked and arranged along the thickness direction thereof, and two adjacent groups of bipolar batteries are fixed by a support member and a hollow layer is arranged between the two groups, and a liquid injection hole is arranged on the side of any group of bipolar batteries. The battery pack is provided with a hollow layer between two adjacent groups of bipolar batteries, and the front and back sides of each group of bipolar batteries can exchange heat, which greatly increases the heat exchange area between the battery pack and the outside world, and facilitates the heat dissipation and cooling of the battery pack; and the battery pack is composed of bipolar batteries, and bipolarity refers to two polarities formed by coating the positive electrode paste and the negative electrode paste on both sides of a substrate, respectively. Therefore, the bipolar battery is thinner than the traditional battery, which is conducive to helping the battery pack control its overall volume under the premise of adding a hollow layer.

Description

A secondary battery system

Technical Field

The present invention relates to the technical field of new energy batteries, and in particular to a secondary battery system.

Background Art

Secondary batteries, also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate the active materials after being discharged and continue to be used. A secondary battery system refers to a battery assembly that is formed by packaging, encapsulating and assembling multiple cells to form a certain shape. In the related art, a secondary battery system cools the cells by setting a cold plate under the cells, but the cells only exchange heat with the cold plate through their bottom surface to achieve heat dissipation and cooling purposes, and thus there is a disadvantage of a small heat exchange area between the cold plate and the cells.

Summary of the invention

In order to overcome the deficiencies in the prior art, the present application provides a secondary battery system, comprising a housing and a plurality of groups of bipolar batteries contained in the housing, wherein the plurality of groups of bipolar batteries are stacked and arranged along the thickness direction thereof, two adjacent groups of bipolar batteries are fixed by a support member and a hollow layer is arranged between the two groups, and a liquid injection hole is arranged on the side of any group of bipolar batteries;

The bipolar battery comprises:

A conductive substrate, wherein the conductive substrate has a first surface and a second surface arranged opposite to each other in a first direction, the first surface is coated with a positive electrode active material, and the second surface is coated with a negative electrode active material to form a bipolar pole piece; the conductive substrate is penetrated between the first surface and the second surface to form a first channel;

The frame is arranged along the periphery of the bipolar pole piece and seals the bipolar pole piece; the frame has two side surfaces arranged opposite to each other in the second direction, and the two ends of the first channel extend to the two side surfaces respectively and form two openings connected to the outside.

In a possible implementation manner, the surface area of the hollow layer is less than or equal to the surface area of the bipolar battery, and a plurality of penetrating second channels are provided in the hollow layer.

In a possible implementation manner, a direction of the second channel and a direction of the first channel are perpendicular to each other.

In a possible implementation, the conductive substrate includes two current collectors stacked and combined along the first direction, the facing surfaces of the two current collectors are relatively recessed to form a first groove, and the projections of the two oppositely arranged first grooves in the first direction overlap to form the first channel.

In a possible implementation manner, the first grooves are distributed on the current collector at equal intervals.

In a possible implementation manner, a second groove is disposed on the first surface and/or the second surface, and the number of the first groove and the number of the second groove are both plural, and the projections of the first groove and the second groove in the first direction are staggered with each other.

In a possible implementation, a plurality of first channels are provided in the conductive substrate and are arranged to pass air or heat exchange liquid; a plurality of the first channels tend to converge at the first end, and a plurality of the first channels extending from the first end to the second end tend to diverge.

In a possible implementation manner, the side surface protrudes at the first end to form a clamping portion.

In a possible implementation manner, the first channel is in a straight line or irregular flow channel at a portion away from the first end.

In a possible implementation, the frame is sealed by any one of ultrasonic welding, hot plate welding, laser welding, and friction welding. In this way, the individual frames are melted together and the bipolar pole pieces are sealed to prevent leakage of the battery electrolyte.

In a possible implementation, the conductive substrate is a metal piece, and at least one of a nickel layer, a carbon layer, a titanium layer and other conductive coatings is coated on the surface of the current collector constituting the first channel.

In a possible implementation manner, the bipolar batteries on opposite sides are connected to the inner side of the housing through an insulating plate.

Compared with the prior art, the present invention has the following beneficial effects:

1. The secondary battery system is provided with a hollow layer between two adjacent groups of bipolar batteries. The front and back sides of each group of bipolar batteries can exchange heat, which greatly increases the heat exchange area between the secondary battery system and the outside world, and facilitates the heat dissipation and cooling of the secondary battery system. The secondary battery system is composed of bipolar batteries. Bipolarity refers to the two polarities formed by coating the positive electrode paste and the negative electrode paste on both sides of a substrate. Therefore, the bipolar battery is thinner than the traditional battery, which is conducive to helping the secondary battery system control its overall volume under the premise of adding a hollow layer.

2. The bipolar battery includes a conductive substrate and a frame, wherein the conductive substrate is penetrated between the first surface and the second surface to form a first channel, and the two ends of the first channel extend to the two sides of the frame respectively and form two openings connected to the outside. Therefore, air (including hot air flow and normal temperature air) or coolant can flow in from one end of the first channel and flow out from the other end, thereby penetrating the entire first channel, and then taking away the heat at the conductive substrate or heating the conductive substrate. It can be seen that the setting of the first channel not only increases the surface area of the conductive substrate, but also increases the heat exchange area between the conductive substrate and the air; at the same time, the design of the two ends of the conductive substrate being open allows the fluid to completely pass through the conductive substrate, so the first channel also provides favorable conditions for convection heat dissipation and preheating of the conductive substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

FIG1 is a schematic diagram showing a bipolar battery with the conductive substrate exposed after the outer shell and the guide plate are removed;

FIG2 shows a schematic diagram of a single conductive substrate from a first angle;

FIG3 shows a second angle schematic diagram of a single conductive substrate;

FIG4 shows a partial enlarged view of point A in FIG1 ;

FIG5 shows a partial enlarged view of point B in FIG2 ;

FIG6 shows a schematic structural diagram of a single frame unit;

FIG7 shows a partial cross-sectional view of the conductive substrate in the first direction;

FIG8 shows an exploded view of a secondary battery system;

FIG9 shows a side view of a secondary battery system;

FIG10 shows a schematic diagram of a hollow layer on a bipolar battery;

FIG. 11 is a schematic diagram showing a conductive substrate in a bipolar battery with clamping portions disposed on opposite sides.

Description of main component symbols:

100, conductive substrate; 110, first surface; 120, second surface; 130, first channel; 131, first end; 132, second end; 140, current collector; 150, first groove; 160, second groove; 200, frame; 210, injection hole; 220, frame unit; 230, clamping part; 300, positive electrode active material; 400, negative electrode active material; 500, diaphragm; 600, bipolar battery; 610, hollow layer; 620, support member; 630, second channel; 700, insulating plate; 800, outer shell.

DETAILED DESCRIPTION

Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

Embodiment 1

Secondary batteries, also known as rechargeable batteries or storage batteries, refer to batteries that can be recharged to activate the active materials after being discharged and continue to be used. A secondary battery system refers to a battery assembly that is formed by packaging, encapsulating and assembling multiple cells to form a certain shape. In the related art, a secondary battery system cools the cells by setting a cold plate under the cells, but the cells only exchange heat with the cold plate through their bottom surface to achieve heat dissipation and cooling purposes, and thus there is a disadvantage of a small heat exchange area between the cold plate and the cells.

In order to overcome the shortcomings of the existing secondary battery system, the present application provides a secondary battery system. Please refer to Figures 8 and 9. The secondary battery system includes a housing 800 and several groups of bipolar batteries 600 housed in the housing 800. Several groups of bipolar batteries 600 are stacked and arranged along the thickness direction. Two adjacent groups of bipolar batteries are fixed by a support 620 and a hollow layer 610 is set between the two. The side of any group of bipolar batteries is provided with several injection holes. Since the front and back sides of each group of bipolar batteries can exchange heat, the heat exchange area between the secondary battery system and the outside world is greatly increased. And the secondary battery system is composed of bipolar batteries. Bipolarity refers to the two polarities formed by applying positive electrode paste and negative electrode paste on both sides of a substrate. Therefore, the bipolar battery is thinner than the traditional battery, which is conducive to helping the secondary battery system control its overall volume under the premise of adding a hollow layer 610.

Please refer to FIG. 1 , the bipolar battery includes a conductive substrate 100 and a frame 200 , wherein most of the structure of the conductive substrate 100 is enclosed by the frame 200 , and only a portion for heat dissipation is exposed from the frame 200 .

Referring to FIG. 2 to FIG. 4 , the conductive substrate 100 has a first surface 110 and a second surface 120 arranged opposite to each other in the first direction. The first surface 110 is coated with a positive electrode active material 300, and the second surface 120 is coated with a negative electrode active material 400 to form a bipolar pole piece. The conductive substrate 100 is penetrated between the first surface 110 and the second surface 120 to form a first channel 130, and the first channel is used to heat or cool the conductive substrate. Specifically, the conductive substrate 100 is generally in a plate-like structure, and the first direction is the thickness direction of the bipolar battery and the conductive substrate 100. The size of the conductive substrate 100 in the thickness direction is significantly smaller than the size in other directions. The first surface 110 and the second surface 120 occupy most of the surface area of the conductive substrate 100, which is used to fully coat and conduct the heat generated by the positive and negative electrode active materials 400; since the first channel 130 is located between the first surface 110 and the second surface 120, the heat generated on both sides of the conductive substrate 100 can be dissipated through the first channel 130.

The frame 200 is arranged along the periphery of the bipolar pole piece and is sealed to form the bipolar pole piece; the frame 200 is provided with a liquid injection hole 210 in its circumferential direction to allow the electrolyte to flow into the areas on both sides of the conductive substrate 100. The frame 200 has two side surfaces arranged opposite to each other in the second direction, and the two side surfaces are provided with openings arranged in cooperation with the first channel 130, and the two ends of the first channel 130 extend to the two side surfaces respectively and communicate with the outside through the openings on the side surfaces. In some embodiments, the frame 200 has a rectangular structure, and the second direction is the length direction of the frame 200 and is perpendicular to the first direction.

Please refer to FIG. 2 to FIG. 4 . Since the ends of the first channel 130 form openings located on two opposite sides of the bipolar battery, the two openings are not on the first surface 110 or the second surface 120 and will not be blocked by the frame 200 or the positive and negative active materials 400. Air (including hot air flow and normal temperature air) or coolant can flow in from the opening at one end of the first channel 130 and flow out from the opening at the other end, thereby penetrating the entire first channel 130, and then taking away the heat at the conductive substrate 100 or heating the conductive substrate. It can be seen that the setting of the first channel 130 not only increases the surface area of the conductive substrate 100, but also increases the heat exchange area between the conductive substrate 100 and the air; at the same time, the design of the conductive substrate 100 being open at both ends allows the fluid to completely pass through the conductive substrate 100, so the first channel 130 also provides favorable conditions for convection heat dissipation and preheating of the conductive substrate 100.

In other optional embodiments, the conductive substrate 100 may also be a plate body in a circular, trapezoidal or other shapes. Optionally, the conductive substrate 100 may not be a plate body, and thus has no obvious thickness direction.

Please refer to FIG. 4 . In some embodiments, a bipolar battery has a plurality of conductive substrates 100 stacked and spaced along a first direction. The conductive substrates 100 and the positive and negative active materials 400 applied thereon form a single battery unit, and adjacent battery units are spaced apart by separators 500. Specifically, the battery active materials coated on the facing surfaces of adjacent conductive substrates 100 are always different, so that the two sides of all separators 500 are respectively coated with positive active materials 300 and negative active materials 400, and the surfaces of the two most edge conductive substrates 100 in the first direction are respectively coated with positive active materials 300 and negative active materials 400. In addition, the projections of the plurality of conductive substrates 100 and the plurality of battery units in the first direction overlap to form a plate-like battery structure.

Please refer to FIG. 1 and FIG. 6 . In some embodiments, the frame 200 is composed of a plurality of frame units 220 stacked together. Each frame unit 220 is provided with a liquid injection hole 210 . Each battery unit is provided with a corresponding liquid injection hole 210 on the frame unit 220 .

Please refer to Figures 3 and 10. In some embodiments, the surface area of the hollow layer is less than or equal to the surface area of the bipolar battery, and a plurality of through second channels 630 are provided in the hollow layer; the direction of the second channels 630 is perpendicular to the direction of the first channels. The first channel generally extends along the length direction of the bipolar battery, and the second channel 630 generally extends along the width direction of the bipolar battery.

Please refer to Figures 5 and 7. The shaded part and the white part in Figure 7 represent two current collectors 140 combined together. In some embodiments, the conductive substrate 100 includes two current collectors 140 stacked and combined along a first direction. The facing surfaces of the two current collectors 140 are relatively concave to form a first groove 150. The relative concave here means that the directions of the concave of the two facing surfaces are opposite. For example, the facing surface of one current collector 140 is concave upward, and the facing surface of the other current collector 140 combined with it is concave downward. The projections of the two first grooves 150 arranged opposite to each other in the first direction overlap to form a first channel 130. Specifically, the two current collectors can be fixedly connected by welding or integral molding.

Designing the conductive substrate 100 to be formed by combining two current collectors 140 is conducive to reducing the production cost of the conductive substrate 100. It is understandable that the processing cost of penetrating the side of the plate-like member to form the first channel 130 is much greater than producing two plate-like members with grooves, and the two current collectors 140 can be designed as standard parts of the same shape, further reducing the production cost.

In some preferred embodiments, the first groove 150 is a square groove, and two relatively recessed square grooves form a first channel 130 with a rectangular cross-section; this is set because the conductive substrate 100 is generally also square, and setting the cross-section of the first channel 130 to a rectangle is conducive to making the thickness of the conductive substrate 100 uniform; in other optional embodiments, the cross-sectional shape of the first channel 130 can be adjusted, such as being set to a circular, elliptical or other forms of polygons to make it adapt to the shape of the conductive substrate 100.

In some embodiments, the first grooves 150 are evenly spaced on the current collector 140 . This arrangement is to allow the conductive substrate 100 to evenly dissipate heat to the first channels 130 .

Please refer to FIG. 5 and FIG. 7. In some embodiments, a second groove 160 is provided on the first surface 110 and/or the second surface 120. The number of the first groove 150 and the second groove 160 are both multiple, and the projections of the two in the first direction are interlaced. The second groove 160 is used to accommodate the positive active material 300 or the negative active material 400 to increase the adhesion between the positive and negative active materials 400 and the conductive substrate 100. The first groove 150 and the second groove 160 are arranged in a staggered manner, which is conducive to the conductive substrate 100 to dissipate heat from different angles, and is also conducive to thinning the thickness of the entire conductive substrate 100, that is, the thickness of the entire conductive substrate 100 can be less than the sum of the depths of the first groove 150 and the second groove 160, and the side of the conductive substrate 100 is also made to be S-shaped, which is conducive to increasing the overall specific surface area of the conductive substrate 100 and improving the heat dissipation effect of the conductive substrate 100.

In some optional embodiments, the shapes of the first groove 150 and the second groove 160 are adapted. For example, when the first groove 150 is a square groove, the second groove 160 is also a square groove; when the first groove 150 is a semicircular groove, the second groove 160 is also a semicircular groove. This arrangement can make it easier for the current collector 140 to be stamped on both sides of the original part forming the current collector 140 by a stamping part of the same shape, thereby reducing production costs.

Please refer to FIG. 2 and FIG. 3. In some optional embodiments, a plurality of first channels 130 are provided in the conductive substrate 100 at intervals. The first channels are configured to pass air or heat exchange liquid (heat exchange liquid refers to coolant or liquid with a higher temperature than the battery. The specific temperature of the liquid passed depends on whether the purpose of cooling or heating the battery is determined); a plurality of first channels 130 tend to converge at the first end 131, and a plurality of first channels 130 extending from the first end 131 to the second end 132 tend to diverge. It should be noted that the divergent trend of the first channels 130 referred to here includes at least one of the following two meanings: the first meaning is that the spacing between the first channels 130 gradually increases, and the second meaning is that the width of the first channels 130 gradually increases.

It should be understood that a fan can be provided at one end of the first channel 130 to accelerate the convective heat dissipation of the conductive substrate 100. The first end 131 here refers to the end where the fan draws air into the first channel 130, and the second end 132 refers to the end where the air is sucked into the first channel 130. The first channels 130 are converged at the first end 131, which is conducive to concentrating the wind force of the fan and increasing the flow rate of the air in the conductive substrate 100; the first channels 130 extending from the first end 131 to the second end 132 are divergent, which is conducive to the first channels 130 covering all areas inside the conductive substrate 100, so that all areas of the conductive substrate 100 can dissipate heat through the first channels 130. In some other embodiments, the first channel 130 can also be connected to a circulating water machine, and the circulating water machine injects cooling water or hot water into the first channel to achieve the purpose of cooling the battery and preheating the battery respectively.

In some optional embodiments, the side surface of the frame 200 protrudes on one side of the first end 131 to form a clamping portion 230. The clamping portion 230 is used to connect and fix the fan and the bipolar battery.

In some optional embodiments, the first channel 130 is linear or irregular in a portion away from the first end 131. It is understandable that when the first channel 130 is linear, it is beneficial to maintain the wind speed of the air sucked into the first channel 130. If the first channel 130 is spiral, it is easy to reduce the wind speed of the sucked air due to being blocked by the conductive substrate 100.

In some preferred embodiments, considering that the first channels 130 need to converge at the first end 131, the shapes of the first channels 130 can be designed to be different. Referring to FIG. 2 , the first channels 130 in the middle of the conductive substrate 100 are all straight-line as a whole, and the wind speed of the blown air is maintained to the maximum extent. The first channels 130 on both sides of the conductive substrate 100 diverge from the first end 131 to the center of the conductive substrate 100 until all areas on the conductive substrate 100 are covered by the first channels 130, and then the first channels 130 on both sides of the conductive substrate 100 extend along a straight line toward the second end 132.

In some preferred embodiments, the frame 200 is sealed by ultrasonic welding. Through ultrasonic welding, the individual frames 200 are melted together and the bipolar pole pieces are sealed to prevent leakage of the electrolyte of the battery.

In some optional embodiments, the conductive substrate 100 is a metal member, and at least one of a nickel layer, a carbon layer, and a titanium layer is coated on the surface of the conductive substrate 100 constituting the first channel 130 .

Considering that the conductive substrate 100 needs to transfer the heat of the bipolar battery to the air, the conductive substrate 100 is preferably made of a metal with a high thermal conductivity, such as copper; at the same time, the metal can also ensure good structural strength. Furthermore, a nickel layer or a carbon layer can be coated on the surface of the conductive substrate 100 forming the first channel 130 to further improve the heat dissipation efficiency.

In some embodiments, the bipolar batteries on opposite sides are connected to the inner side of the housing 800 through the insulating plate 700. Please refer to Figure 8 for details, in which it can be seen that the housing 800 and the insulating plate 700 on opposite sides are locked by bolts and contain several groups of bipolar batteries.

In some embodiments, clamping parts are provided on both sides of the bipolar battery. In this case, the structural diagram of the conductive substrate in the bipolar battery is shown in FIG. 11 . It can be seen from the figure that the two ends of a plurality of first channels converge at the positions of two relative clamping parts, respectively, to facilitate the input of fluid into the first channels through the two clamping parts.

In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims (10)

1. A secondary battery system, characterized in that it comprises a housing and a plurality of groups of bipolar batteries contained in the housing, wherein the plurality of groups of bipolar batteries are stacked and arranged along the thickness direction thereof, two adjacent groups of bipolar batteries are fixed by a support member and a hollow layer is arranged between the two groups, and a liquid injection hole is arranged on the side of any group of bipolar batteries; The bipolar battery comprises: A conductive substrate, wherein the conductive substrate has a first surface and a second surface arranged opposite to each other in a first direction, the first surface is coated with a positive electrode active material, and the second surface is coated with a negative electrode active material to form a bipolar pole piece; the conductive substrate is penetrated between the first surface and the second surface to form a first channel; The frame is arranged along the periphery of the bipolar pole piece and seals the bipolar pole piece; the frame has two side surfaces arranged opposite to each other in the second direction, and the two ends of the first channel extend to the two side surfaces respectively and form two openings connected to the outside. 2 . The secondary battery system according to claim 1 , wherein the surface area of the hollow layer is less than or equal to the surface area of the bipolar battery, and a plurality of penetrating second channels are provided in the hollow layer. 3 . The secondary battery system according to claim 2 , wherein a direction of the second channel is perpendicular to a direction of the first channel. 4. The secondary battery system according to claim 1 is characterized in that the conductive substrate comprises two current collectors stacked and combined along the first direction, the facing surfaces of the two current collectors are relatively recessed to form a first groove, and the projections of the two oppositely arranged first grooves in the first direction overlap to form the first channel. 5 . The secondary battery system according to claim 4 , wherein the first grooves are distributed at equal intervals on the current collector. 6 . The secondary battery system according to claim 4 , wherein a second groove is provided on the first surface and/or the second surface, the first groove and the second groove are both multiple in number, and their projections in the first direction are staggered. 7. The secondary battery system according to claim 1 is characterized in that a plurality of first channels are provided in the conductive substrate at intervals, and the first channels are configured to pass air or heat exchange liquid; a plurality of the first channels tend to converge at the first end, and a plurality of the first channels extending from the first end to the second end tend to diverge; the side surface protrudes at the first end to form a clamping portion. 8 . The secondary battery system according to claim 1 , wherein the frame is sealed by any one of ultrasonic welding, hot plate welding, laser welding and friction welding. 9 . The secondary battery system according to claim 4 , wherein the conductive substrate is a metal piece, and at least one of a nickel layer, a carbon layer, a titanium layer and the like conductive coating is coated on the surface of the current collector constituting the first channel. 10 . The secondary battery system according to claim 1 , wherein the bipolar batteries on opposite sides are connected to the inner side of the housing through an insulating plate.