Thermal composite battery cell

Abstract

The utility model discloses a thermal composite battery cell, which comprises N negative plates, M positive plates and a diaphragm, the M positive plates, N-M = 1; a negative tab is arranged on the negative plate, a positive tab is arranged on the positive plate, the diaphragm comprises a plurality of main body parts and a plurality of bent parts which are alternately and continuously arranged, the negative plate and the positive plate are alternately stacked along the thickness direction of the negative plate, the adjacent negative plate and positive plate are separated by the main body parts, and the bent parts are provided with incompletely cut structures. The diaphragm is folded along the incompletely cut structure, and at least partial structures of the negative pole lug and the positive pole lug are positioned on the outer side of the diaphragm; wherein the two negative electrode plates positioned on the outermost side are single-sided electrode plates, and the other negative electrode plates are double-sided electrode plates. The problem that an existing thermal composite battery cell is poor in alignment degree is solved, and the thermal composite battery cell has the advantages of being good in alignment degree and stable in performance.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular to thermal composite battery cells. Background Art

[0002] At present, battery cells are mainly made by folding or winding processes. Laminated cells have been widely used due to their many advantages. The pole pieces of laminated cells are in a free fall state during the folding process. The negative and positive pole pieces in the laminated cells are misaligned, and the alignment of the laminated cells is poor. During the battery charging process, lithium ions are deintercalated from the positive pole piece and embedded in the negative pole piece. Due to the misalignment of the positive and negative pole pieces, the lithium ions cannot be completely embedded in the negative pole piece. The lithium ions that cannot be embedded in the negative pole piece can only obtain electrons on the surface of the negative pole piece, thereby forming a white metallic lithium single substance, and lithium plating occurs. Lithium plating greatly shortens the cycle life of the battery, limits the fast charging capacity of the battery, and may also cause combustion and explosion, etc., posing a safety hazard and reducing the performance of the battery.

[0003] In the related art, in order to improve the alignment of the laminated battery cells, a shaping process is added during the production of the laminated battery cells. After the thermal composite unit is folded by free fall to form a battery cell, a shaping cylinder is used to clamp the battery cell from both sides to align the various pole pieces in the battery cell. Relying on the shaping cylinder to shape the battery cell still has the problem of poor alignment of the battery cell, and there is a situation in which the pole piece is beaten off during the shaping process of the shaping cylinder, which increases the risk of short circuit of the core package. Utility Model Content

[0004] The embodiment of the present application provides a stacked battery cell. The stacked battery cell achieves the technical effects of good folding quality, high folding efficiency and good alignment by setting an incompletely cut structure on the bent portion of the diaphragm, and the diaphragm is folded along the incompletely cut structure.

[0005] In a first aspect, an embodiment of the present application provides a thermal composite battery cell, comprising:

[0006] N negative electrode sheets, N is a positive integer greater than 1, and each negative electrode sheet is provided with a negative electrode tab;

[0007] M positive electrode sheets, M is a positive integer greater than 1, and NM=1, and the positive electrode sheets are provided with positive electrode tabs;

[0008] A diaphragm, the diaphragm comprising a plurality of main bodies and a plurality of bent parts arranged alternately and continuously, wherein, along the thickness direction of the negative electrode sheet, the negative electrode sheet and the positive electrode sheet are alternately stacked, the adjacent negative electrode sheet and the positive electrode sheet are separated by the main body, the bent part is provided with an incompletely cut structure, the diaphragm is folded along the incompletely cut structure, and at least part of the structure of the negative electrode tab and the positive electrode tab is located outside the diaphragm;

[0009] Among them, the two negative electrode sheets located on the outermost sides are the single-sided electrode sheets, and the other negative electrode sheets are the double-sided electrode sheets.

[0010] Optionally, the single-sided electrode sheet comprises a negative electrode current collector and a negative electrode active layer, and the negative electrode active layer is disposed on a side of the negative electrode current collector close to the main body;

[0011] And / or, the double-sided electrode sheet comprises a negative electrode current collector and a negative electrode active layer, and the negative electrode active layer is disposed on both sides of the negative electrode current collector.

[0012] Optionally, the diaphragm includes a first diaphragm and a second diaphragm, the first diaphragm includes a first main body portion and a first bending portion, the second diaphragm includes a second main body portion and a second bending portion, and the first bending portion and / or the second bending portion are provided with the incompletely cut structure.

[0013] Optionally, both the first bending portion and the second bending portion are provided with the incompletely cut structure, and a projection of the incompletely cut structure on the first bending portion on the second diaphragm overlaps with the incompletely cut structure on the second bending portion.

[0014] Optionally, the incompletely cut structure includes a plurality of through holes penetrating the diaphragm, and the plurality of through holes are arranged at intervals along the width direction of the diaphragm.

[0015] Optionally, the intervals between adjacent through holes are the same.

[0016] Optionally, the through hole is circular or rectangular in shape.

[0017] Optionally, along the width direction of the diaphragm, an interval between adjacent through holes is S1, wherein 5 mm ≤ S1 ≤ 20 mm.

[0018] Optionally, the through hole has a first size L1 and a second size W1, the first size is the distance between two parallel planes virtually abutting the hole walls on both sides of the through hole, and the second size is the distance between two parallel planes virtually abutting the hole walls at both ends of the through hole, wherein 1mm≤L1≤20mm, and / or, 1mm≤W1≤2mm.

[0019] Optionally, the long side dimension of the negative electrode sheet is greater than the long side dimension of the positive electrode sheet, and the wide side dimension of the negative electrode sheet is greater than the wide side dimension of the positive electrode sheet.

[0020] Optionally, the distance between the long side of the positive electrode sheet and the long side of the negative electrode sheet is S2, 1mm≤S2≤3mm;

[0021] And / or, the distance between the wide side of the positive electrode sheet and the wide side of the negative electrode sheet is S3, 1mm≤S3≤3mm.

[0022] Optionally, the long side dimension of the main body is greater than the long side dimension of the negative electrode sheet, and the wide side dimension of the main body is greater than the wide side dimension of the negative electrode sheet.

[0023] Optionally, the distance between the long side of the negative electrode sheet and the long side of the separator is S4, wherein 2mm≤S4≤4mm;

[0024] And / or, the separator continuously includes a starting end, and a distance between the starting end and a wide side of the negative electrode sheet close to the starting end is S5, wherein 1 mm≤S5≤3 mm.

[0025] Optionally, the thickness of the negative electrode current collector is D1, 4 μm≤D1≤6 μm;

[0026] And / or, the thickness of the negative electrode active layer is D2, 50 μm≤D2≤200 μm.

[0027] Optionally, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer, and the positive electrode active layer is disposed on both sides of the positive electrode current collector.

[0028] Optionally, the negative electrode sheet, the positive electrode sheet and the separator are thermally composited and connected.

[0029] Optionally, along the thickness direction of the negative electrode sheet, the projections of all the negative electrode tabs overlap, and / or the projections of all the positive electrode tabs overlap.

[0030] Optionally, the projections of the negative electrode tab and the positive electrode tab within the plane where the main body is located are arranged side by side.

[0031] The thermal composite battery cell provided in the embodiment of the present application comprises N negative electrode sheets, M positive electrode sheets and a separator, wherein the number of negative electrode sheets is one more than the number of positive electrode sheets, the separator comprises a main body and a bending portion, adjacent main bodies are connected by the bending portion, each bending portion is provided with an incompletely cut structure, along the thickness direction of the negative electrode sheets, the negative electrode sheets and the positive electrode sheets are alternately stacked, and each positive electrode sheet is located between two negative electrode sheets, and adjacent negative electrode sheets and positive electrode sheets are separated by the main body to avoid the negative electrode sheets and the positive electrode sheets from directly contacting each other and causing a short circuit, the separator is not completely cut, It can be folded continuously along the straight line where the incompletely cut portion is located, and each time it is folded along the straight line where the incompletely cut portion is located, the folding position is fixed, thereby ensuring the alignment of the positive electrode sheet and the negative electrode sheet in the folded battery cell, the two outermost negative electrode sheets are single-sided electrode sheets, and the other negative electrode sheets are double-sided electrode sheets, and the outer side of the outermost negative electrode sheet does not need to be coated, thereby reducing material input and reducing costs, overcoming the problem of poor alignment of existing thermal composite battery cells, and having good alignment of the stacked battery cells, thereby reducing the occurrence of lithium plating and improving the electrical performance of the stacked battery cells in terms of cycle life, fast charging capacity and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0033] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0034] Figure 1 A three-dimensional diagram of a thermal composite battery cell provided in an embodiment of the present application.

[0035] Figure 2 A top view of a thermal composite battery cell provided in an embodiment of the present application.

[0036] Figure 3 for Figure 2 The first form of sectional view in AA.

[0037] Figure 4 for Figure 3 A partial enlarged view of point A in the middle.

[0038] Figure 5 for Figure 2 The second form of sectional view of AA.

[0039] Figure 6 for Figure 5 A partial enlarged view of point B in the middle.

[0040] Figure 7 This is a labeled diagram of the thermal composite battery cell provided in an embodiment of the present application.

[0041] Figure 8 A schematic diagram of a composite stack in a form of a method for preparing a thermal composite battery cell provided in an embodiment of the present application.

[0042] Fig. 9 A schematic diagram of another form of composite stacking in the method for preparing a thermal composite battery cell provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0044] The thermal composite battery cell of the embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0045] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, Figure 1 A three-dimensional diagram of a thermal composite battery cell provided in an embodiment of the present application. Figure 2 A top view of a thermal composite battery cell provided in an embodiment of the present application. Figure 3 for Figure 2 The first form of sectional view in AA, Figure 4 for Figure 3 The partial enlarged view of A in the middle shows that the embodiment of the present application provides a thermal composite battery cell, including N negative electrode sheets 100, M positive electrode sheets 200 and a separator 300. The battery cell can be used as an energy storage unit of a battery, and the battery can convert the energy stored in the battery cell into current and supply it to electronic devices.

[0046] In this embodiment, see Figure 1 As shown, the negative electrode sheet 100 and the positive electrode sheet 200 are cut from a negative electrode material roll and a positive electrode material roll, respectively. The negative electrode sheet 100 and the positive electrode sheet 200 are both rectangular in shape. The negative electrode sheet 100 is provided with a negative electrode tab 130, and the positive electrode sheet 200 is provided with a positive electrode tab 210. The negative electrode tab 130 and the positive electrode tab 210 extend out of the separator 300. The positive electrode tab 210 and the negative electrode tab 130 may both be at least partially located outside the separator 300.

[0047] In this embodiment, N negative electrode sheets 100 and M positive electrode sheets 200 are provided, and the values ​​of N and M are both positive integers greater than 1, NM=1, and the numbers of N and M are specifically multiple according to the energy storage design of the foldable battery cell, but the number of negative electrode sheets 100 is always one more than the number of positive electrode sheets.

[0048] In this embodiment, see Figure 1 As shown, the separator 300 is a continuous film material, and the separator 300 includes a plurality of main bodies 310 and a plurality of bending parts 320 that are alternately and continuously arranged, and the plurality of main bodies 310 are stacked and arranged along the thickness direction X of the negative electrode sheet 100, and the adjacent main bodies 310 are connected by the bending parts 320, and the bending parts 320 are provided with an incomplete cutting structure 330, and the separator 300 is bent at the incomplete cutting structure 330. Exemplarily, the material of the separator 300 can be polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, ethylene-propylene copolymer, cellulose, etc.

[0049] In some embodiments, see Figure 3 and Figure 4 As shown, along the thickness direction X of the negative electrode sheet 100, the negative electrode sheet 100 and the positive electrode sheet 200 are alternately stacked, each positive electrode sheet 200 is located between two negative electrode sheets 100, and the adjacent negative electrode sheets 100 and positive electrode sheets 200 are separated by the main body 310. The two negative electrode sheets 100 located on the outermost side are single-sided electrode sheets B, and the other negative electrode sheets 100 are double-sided electrode sheets 100A. The projections of the positive electrode sheet 200 and the negative electrode sheet 100 along the thickness direction of the negative electrode sheet 100 completely fall within the plane area of ​​the main body 310 between the two, so that the main body 310 can completely separate the negative electrode sheet 100 and the positive electrode sheet 200, and prevent the positive electrode sheet 200 from contacting the negative electrode sheet 100 and causing a short circuit. Among them, the plane area of ​​the main body 310 is a continuous planar area surrounded by the outer contour of the projection of the main body 310 along the thickness direction of the negative electrode sheet 100.

[0050] It can be understood that before folding, the diaphragm 300 is in a continuous strip structure, and the negative electrode sheet 100 and the positive electrode sheet 200 are compounded on the main body 310 of the diaphragm 300 to form a composite laminate, and an incompletely cut structure 330 is provided on the diaphragm 300, and the distances between the two sides of the incompletely cut structure 330 and the negative electrode sheet 100 on its side are the same or approximately the same, and the composite laminate is folded along the straight line where the incompletely cut structure 330 is located. The folding position is fixed, which improves the alignment during the folding process, avoids the situation where lithium plating pierces the diaphragm 300 due to the misalignment of the negative electrode sheet 100 and the positive electrode sheet 200, and improves the electrical performance of the folded battery cell. The outermost negative electrode sheet 100 is set as a single-sided electrode sheet 100B, and the outermost side of the single-sided electrode sheet 100B does not need to be provided with an active material layer, thereby reducing material input and reducing costs.

[0051] In some embodiments, the negative electrode sheet 100, the positive electrode sheet 200 and the separator 300 are thermally composited and connected. The negative electrode sheet 100 and the positive electrode sheet 200 are thermally composited on the separator 300, which means that the negative electrode sheet 100 and the positive electrode sheet 200 are fixed on the surface of the separator 300 through a thermal composite process. Exemplarily, the thermal composite process is as follows: the positive electrode material roll, the negative electrode material roll, and the separator are fed at the same time. Before entering the heating device, the positive electrode sheet 200 and the negative electrode sheet 100 are cut into single electrodes of the required size by a cutter. The assembly of the positive electrode sheet 200, the negative electrode sheet 100, and the separator 300 enters the heating system under the action of the roller. The separator 300 is a glue-coated separator, which is sticky after heating. After baking, the positive electrode sheet 200, the negative electrode sheet 100 and the separator 300 are thermally composited, and then rolled and cut to form a composite laminate.

[0052] In some embodiments, see Figure 1 and Figure 2 As shown, along the thickness direction X of the negative electrode sheet 100, the projections of all the negative electrode tabs 130 overlap, and the projections of all the positive electrode tabs 210 overlap. The negative electrode tabs 130 are stacked with the negative electrode sheet 100, and the positive electrode tabs 210 are stacked with the positive electrode sheet 200. The thickness of the main body 310 is spaced between adjacent negative electrode tabs 130, and the projections of all the negative electrode tabs 130 are at the same position, the thickness of the main body 310 is spaced between adjacent positive electrode tabs 210, and the projections of all the positive electrode tabs 210 are at the same position, which facilitates the welding of all the negative electrode tabs 130 and all the positive electrode tabs 210, and the negative electrode tabs 130 and the positive electrode tabs 210 occupy a small space.

[0053] In some embodiments, see 1 and Figure 2 As shown, the projections of the negative electrode tab 130 of the negative electrode sheet 100 and the positive electrode tab 210 on the positive electrode sheet 200 in the plane where the main body 310 is located are arranged side by side. The negative electrode sheet 100 and the positive electrode sheet 200 are located on both sides of the main body 310, respectively. The projections of the negative electrode tab 130 on the negative electrode sheet 100 and the positive electrode tab 210 on the positive electrode sheet 200 in the plane where the main body 310 is located are arranged at intervals to prevent the negative electrode tab 130 from interfering with the positive electrode tab 210, thereby ensuring electrical safety.

[0054] In some embodiments, see Figure 4 As shown, the double-sided electrode sheet 100A includes a negative electrode current collector 110 and a negative electrode active layer 120 , and the negative electrode active layer 120 is disposed on both sides of the negative electrode current collector 110 .

[0055] In some embodiments, the single-sided electrode sheet 100B includes a negative electrode current collector 110 and a negative electrode active layer 120. The negative electrode active layer 120 is disposed on one side of the negative electrode current collector 110. Exemplarily, the negative electrode current collector 110 may be made of copper, and the negative electrode active layer 120 may be made of graphite.

[0056] In this embodiment, see Figure 4 As shown, along the thickness direction X of the negative electrode sheet 100, from bottom to top, the N negative electrode sheets 100 are the first negative electrode sheet 100, the second negative electrode sheet 100...the Nth negative electrode sheet 100, the first negative electrode sheet 100 and the Nth negative electrode sheet 100 are located at the outermost side of the thermal composite battery cell, the first negative electrode sheet 100 and the Nth negative electrode sheet 100 use a single-sided electrode sheet 100B, and the other negative electrode sheets 100 use a double-sided electrode sheet 100A, and the negative electrode active layer 120 is set on the side of the negative electrode collector 110 of the first negative electrode sheet 100 and the Nth negative electrode sheet 100 close to the main body 310.

[0057] The outermost negative electrode sheet 100 of the thermal composite battery cell is provided with a single-sided electrode sheet 100B, which reduces the use of negative electrode active materials and reduces processing costs. The outermost side of the single-sided electrode sheet 100B does not need to be coated with a diaphragm 300, which reduces diaphragm materials and further reduces processing costs. Compared with related technologies, two layers of negative electrode active layers 120 and two layers of diaphragms 300 are reduced, reducing the thickness of the thermal composite battery cell.

[0058] In some embodiments, the number of separators 300 may be multiple, and multiple separators 300 may be stacked along the thickness direction of the negative electrode sheet 100. Exemplarily, the battery cell may include a double-layer separator, or may include more layers of separators. The embodiments of the present application are described using a double-layer separator as an example, and embodiments of separators with other layers may be adaptively designed based on the embodiments of the double-layer separator.

[0059] In some embodiments, see Figure 3 and Figure 4 As shown, the separator 300 includes a first separator 340 and a second separator 350. The first separator 340 and the second separator 350 are both folded in a Z-shape to form a main body 310 and a bent portion 320. Along the thickness direction X of the negative electrode sheet 100, the negative electrode sheet 100 and the positive electrode sheet 200 are alternately stacked, and the adjacent positive electrode sheets 200 and the negative electrode sheet 100 are separated by the main body 310. The bent portion 320 of the first separator 340 is provided with an incompletely cut structure 330 and / or the bent portion 320 of the second separator 350 is provided with an incompletely cut structure 330. Specifically, the following situations are included: all the incompletely cut structures 330 are arranged on the first diaphragm 340; or, all the incompletely cut structures 330 are arranged on the second diaphragm 350; or, a part of the incompletely cut structures 330 are arranged on the first diaphragm 340, and the other part of the incompletely cut structures 330 are arranged on the second diaphragm 350; or, both the first diaphragm 340 and the second diaphragm 350 are provided with incompletely cut structures 330, and the number and position of the incompletely cut structures 330 on the first diaphragm 340 and the second diaphragm 350 are the same.

[0060] For example, see Figure 4 As shown, the battery cell may include a double-layer diaphragm 300, namely a first diaphragm 340 and a second diaphragm 350. The first diaphragm 340 includes a first main body 311 and a first bending portion 321, and the second diaphragm 350 includes a second main body 312 and a second bending portion 322. A negative electrode sheet 100 is provided between any two adjacent first main bodies 311 and second main bodies 312, and a positive electrode sheet 200 is provided between any two adjacent first main bodies 311 and any two adjacent second main bodies 312. An incompletely cut structure 330 is provided on the first diaphragm 340 and the second diaphragm 350. The projection of the incompletely cut structure 330 on the first diaphragm 340 on the second diaphragm 350 overlaps with the continuous planar area surrounded by the outer contour of the incompletely cut structure 330 on the second diaphragm 350. When the diaphragm 300 is folded, the first diaphragm 340 and the second diaphragm 350 are folded along the same straight line, so as to ensure that the main bodies 310 of the layers in the folded battery cell are aligned, thereby improving the alignment of the laminated battery cell.

[0061] For example, see Figure 4 As shown, the first bending portion 321 and the second bending portion 322 can be connected in a close connection, and as long as a part of one of the bending portions is in contact with the other bending portion, the two bending portions can be considered to be in a close connection. In some other embodiments, the first bending portion 321 and the second bending portion 322 may not be in contact, and the embodiments of the present application are not limited to this.

[0062] See also Figure 3 , Figure 4 and Figure 8 As shown, before the diaphragm 300 is folded, the first diaphragm 340 and the second diaphragm 350 are both continuous strip structures, the positive electrode sheet 200 is composited between the first diaphragm 340 and the second diaphragm 350, and the single-sided electrode sheet 100B is composited on the side of the first diaphragm 340 away from the positive electrode sheet 200 and the side of the second diaphragm 350 away from the positive electrode sheet 200, forming a composite laminate. The incompletely cut structure 330 is located between adjacent negative electrode sheets 100, and the distance between the two sides of the incompletely cut structure 330 is the same as the distance between the negative electrode sheets 100 on the side thereof, and the diaphragm 300 (that is, the first diaphragm 340 and the second diaphragm 350) is folded at the incompletely cut structure 330. The incompletely cut structure 330 can release the stress generated by the folding, so that the diaphragm 300 is easy to fold at the incompletely cut structure 330, thereby playing the role of limiting the folding position and improving the folding quality and folding efficiency.

[0063] The embodiment of the present application limits the folding position of the diaphragm 300 by setting an incomplete cutting structure, so that the diaphragm 300 can be folded at basically the same position to ensure the alignment of the negative electrode sheet 100 and the positive electrode sheet 200 in the folded battery cell, and avoid the occurrence of lithium plating piercing the diaphragm 300 due to the misalignment of the negative electrode sheet 100 and the positive electrode sheet 200, thereby improving the electrical performance of the folded battery cell in terms of service life, fast charging capacity, safety, etc.

[0064] In some embodiments, see Figure 1 and Figure 7 As shown, the incompletely cut structure 330 includes a plurality of through holes 331 penetrating the diaphragm 300, and the plurality of through holes 331 are arranged at intervals along the width direction of the diaphragm 300. Alternatively, the plurality of through holes 331 are arranged in an array, and a plurality of columns of through holes 331 are arranged along the length direction Y of the diaphragm 300. Each column of through holes 331 can be arranged along the width direction Z of the diaphragm 300. Exemplarily, the arrangement directions of the plurality of columns of through holes 331 can be parallel to each other. In some other embodiments, there may also be an angle between the arrangement direction of at least one column of through holes 331 and the arrangement direction of the other columns of through holes. Exemplarily, the angle may be less than or equal to 10°, for example, 1°, 2°, 5°, etc. In some other embodiments, the angle may also be greater than 10°, and the embodiments of the present application are not limited thereto. Exemplarily, the plurality of through holes 331 in one of any two columns of through holes 331 may be arranged one by one relative to the plurality of through holes 331 in the other column. In some other embodiments, at least one row of through holes 331 may be arranged alternately with other rows of through holes 331. If the projections of two through holes 331 in the length direction Y of the diaphragm 300 do not overlap, it can be considered that the two through holes 331 are arranged alternately. For example, the multiple through holes 331 in one of the two adjacent rows of through holes 331 may be arranged alternately with the multiple through holes 331 in the other row.

[0065] In some other embodiments, the incompletely cut structure 330 may also include a plurality of gaps spaced apart from each other. The gaps may be obtained by cutting the diaphragm with a knife or the like.

[0066] See also Figure 4 As shown, when the diaphragm 300 includes a first diaphragm 340 and a second diaphragm 350, the incompletely cut structure 330 on the first diaphragm 340 is a through hole 331 that penetrates the first diaphragm 340. The incompletely cut structure 330 on the second diaphragm 350 is a through hole 331 that penetrates the second diaphragm 350. When the incompletely cut structure 330 is provided on both the first diaphragm 340 and the second diaphragm 350, the through hole 331 on the first diaphragm 340 is arranged opposite to the through hole 331 on the second diaphragm 350, and the through hole 331 on the first diaphragm 340 is connected to the through hole 331 on the second diaphragm 350.

[0067] It can be understood that by providing a plurality of through holes 331 on the diaphragm 300 to form an incompletely cut structure 330, local material on the diaphragm 300 is cut off, and the diaphragm 300 is not completely cut along the width direction of the diaphragm 300. Compared with completely cutting the diaphragm 300, the diaphragm 300 will not shrink and wrinkle due to stress changes, and the diaphragm 300 around the through holes 331 is weak. During free fall folding, the diaphragm 300 will fold along the position of the through holes 331 to achieve precise position folding, which is beneficial to the alignment of the negative electrode sheet 100 and the positive electrode sheet 200 in the folded battery cell.

[0068] In some embodiments, see Figure 1 and Figure 7 As shown, Figure 7 A marked diagram of a thermal composite battery cell provided in an embodiment of the present application. The interval between any two adjacent through holes 331 is the same. The interval between adjacent through holes 331 refers to the distance between one side of a through hole 331 and one side of an adjacent through hole 331 along the width direction Z of the diaphragm 300.

[0069] In this embodiment, the intervals between adjacent through holes 331 are the same, which is conducive to processing the through holes 331 on the diaphragm 300, so that the strength of the diaphragm 300 on the straight line where the multiple through holes 331 are located is the same, avoiding the diaphragm 300 from being broken during the folding process due to local weak strength.

[0070] The through hole 331 has a regular shape such as a circle, a rectangle, an ellipse, a hexagon or an octagon. In addition to being a regular shape, the through hole 331 can also be an irregular shape.

[0071] In some embodiments, see Figure 7 As shown, along the width direction Z of the diaphragm 300, the interval between adjacent through holes 331 is S1, wherein 5 mm ≤ S1 ≤ 20 mm. The value of S1 may be 5.0 mm, 5.2 mm, 5.7 mm, 7.8 mm, 9.0 mm, 10.5 mm, 11.5 mm, 12.3 mm, 13.9 mm, 14.0 mm, 15.7 mm, 16.1 mm, 17.4 mm, 18.0 mm, 19.6 mm, 20.0 mm or other unspecified values.

[0072] In the embodiment of the present application, the interval S1 between the through holes 331 is set to be greater than or equal to 5 mm, which can avoid the situation where the distance between the through holes 331 is too small and the number of through holes 331 is too large, which affects the structural strength of the diaphragm 300; the interval S1 between the through holes 331 is set to be less than or equal to 20 mm, which can avoid the situation where the distance between the through holes 331 is too large and the number of through holes 331 is too small, which cannot play the role of positioning folding during the folding process. The interval between the through holes 331 is reasonably designed to ensure the folding quality.

[0073] In some embodiments, see Figure 7 As shown, the through hole 331 is in a rectangular shape, and the through hole 331 has a first size L1 and a second size W1, the first size is the distance between two parallel planes virtually abutting the hole walls on both sides of the through hole 331, and the second size is the distance between two parallel planes virtually abutting the hole walls at both ends of the through hole 331, wherein 1mm≤L1≤20mm, and / or, 1mm≤W1≤2mm. The hole walls on both sides refer to the side walls extending along the width direction Z of the diaphragm 300, and the hole walls at both ends refer to the side walls extending along the length direction Y of the diaphragm 300. In this embodiment, the value of L1 can be 1.1mm, 1.2mm, 1.5mm, 2.3mm, 3.4mm, 4.2mm, 5.0mm, 6.8mm, 7.8mm, 8.8mm, 9.0mm, 10.3mm, 11.1mm, 12.5mm, 13.8mm, 14.1mm, 15.0mm, 16.6mm, 17.7mm, 18.2mm, 19.1mm, 20.0mm or other unspecified values. In this embodiment, the value of W1 can be 1.1mm, 1.2mm, 1.4mm, 1.5mm, 1.8mm, 2.0mm or other unspecified values.

[0074] It should be noted that the two parallel planes virtually abutting the through hole 331 are introduced only for the convenience of understanding the first dimension and the second dimension, and do not actually exist in the solution of the present application. For example, the through hole 331 has a rectangular outer contour. To determine the first dimension and the second dimension, it is assumed that there are two groups of planes, each group of planes includes two parallel planes arranged at intervals, and the two parallel planes of each group can virtually abut the two opposite hole walls of the through hole 331 together. At this time, there is a distance between the two parallel planes of each group. The first dimension is the distance between the two planes abutting the hole walls on both sides of the through hole 331, and the second dimension is the distance between the two planes abutting the hole walls at both ends of the through hole 331.

[0075] It can be understood that the size of the through hole 331 in this embodiment is reasonably designed to avoid affecting the structural strength of the diaphragm 300 due to the through hole 331 being too large, or the through hole 331 being too small to play a role in positioning and folding during the folding process.

[0076] In some embodiments, see Figure 1 , Figure 5 , Figure 6 and Figure 7 As shown, the long side dimension of the negative electrode sheet 100 is greater than the long side dimension of the positive electrode sheet 200, and the wide side dimension of the negative electrode sheet 100 is greater than the wide side dimension of the positive electrode sheet 200. In the thermal composite battery cell, along the thickness direction X of the negative electrode sheet 100, the projection of the positive electrode sheet 200 in the plane where the negative electrode sheet 100 is located completely falls into the negative electrode sheet 100.

[0077] It can be understood that the size of the negative electrode sheet 100 is designed to be larger than that of the positive electrode sheet 200. During the charging process of the lithium battery, the negative electrode sheet 100 can completely receive the lithium ions of the positive electrode sheet 200, reducing the probability of lithium dendrite formation, avoiding the situation where the diaphragm 300 is pierced by the formation of lithium dendrites, resulting in a short circuit and causing thermal runaway, thereby improving the reliability of the battery.

[0078] In some embodiments, see Figure 7 As shown, the distance between the long side of the positive electrode sheet 200 and the long side of the negative electrode sheet 100 is S2, and the distance between the wide side of the positive electrode sheet 200 and the wide side of the negative electrode sheet 100 is S3, wherein 1mm≤S2≤3mm, 1mm≤S3≤3mm. The values ​​of S2 and S3 may be 1mm, 1.3mm, 1.7mm, 1.8mm, 2.0mm, 2.3mm, 2.7mm, 3.0mm or other values ​​not specified.

[0079] The distance S2 between the long side of the positive electrode sheet 200 and the long side of the negative electrode sheet 100 and the distance S3 between the wide side of the positive electrode sheet 200 and the wide side of the negative electrode sheet 100 may be the same or different, which is not specifically limited in this embodiment.

[0080] It can be understood that in this embodiment, the distance S2 between the long side of the positive electrode sheet 200 and the long side of the negative electrode sheet 100 and the distance S3 between the wide side of the positive electrode sheet 200 and the wide side of the negative electrode sheet 100 are reasonably designed to avoid waste of materials due to excessive size and reduce costs while meeting the battery safety performance. Due to the good alignment of the laminated battery cell, the size of the negative electrode sheet 100 exceeding the positive electrode sheet 200 can be appropriately shortened, reducing the material of the negative electrode sheet and reducing costs.

[0081] In some embodiments, see Figure 1 , Figure 4 , Figure 6 and Figure 7 As shown, the long side dimension of the main body 310 is larger than the long side dimension of the negative electrode sheet 100, and the wide side dimension of the main body 310 is larger than the wide side dimension of the negative electrode sheet 100. It can be understood that the size of the main body 310 is larger than the size of the negative electrode sheet 100, and the projection of the negative electrode sheet 100 on the main body 310 completely falls into the continuous planar area surrounded by the outer contour of the main body 310.

[0082] The negative electrode sheet 100 and the positive electrode sheet 200 are separated by the main body 310. If the size of the main body 310 is smaller than that of the negative electrode sheet 100, the negative electrode sheet 100 and the positive electrode sheet 200 may directly contact each other, causing a short circuit and thermal runaway. The size of the main body 310 is designed to be larger than the positive electrode sheet 200 to meet the electrical safety requirements of the thermal composite battery cell and improve the reliability of the thermal composite battery cell.

[0083] In some embodiments, see Figure 7 As shown, the distance between the long side of the negative electrode sheet 100 and the long side of the separator 300 is S4, where 2mm≤S4≤4mm; and / or, the separator 300 includes a starting end 360, and the distance between the starting end 360 and the wide side of the negative electrode sheet 100 closest to the starting end 360 is S5, where 1mm≤S5≤3mm. The long side of the negative electrode sheet 100 refers to the side extending along the length direction Y of the separator 300, and the wide side of the negative electrode sheet refers to the side extending along the width direction Z of the separator 300.

[0084] In this embodiment, the value of S4 can be 2.1mm, 2.3mm, 2.7mm, 3.0mm, 3.4mm, 3.8mm, 3.9mm, 4mm or other unlisted values.

[0085] In this embodiment, the value of S5 can be 1.1mm, 1.2mm, 1.5mm, 1.6mm, 1.8mm, 1.9mm, 2mm, 2.3mm, 2.5mm, 2.7mm, 2.8mm, 2.9mm, 3mm or other unlisted values.

[0086] In this embodiment, the values ​​of S4 and S5 may be the same or different, and this embodiment does not make any specific limitation.

[0087] It can be understood that the dimensions of the negative electrode sheet and the separator 300 are reasonably designed to avoid material waste due to the separator 300 being too large while ensuring electrical safety, thereby reducing processing costs.

[0088] In some embodiments, see Figure 4 As shown, the thickness of the negative electrode current collector 110 is D1, 4.0 μm ≤ D1 ≤ 6.0 μm. The value of D1 can be 4.0 μm, 4.1 μm, 4.7 μm, 5.0 μm, 5.4 μm, 5.6 μm, 6.0 μm or other unspecified values. The thickness of the negative electrode current collector 110 is reasonably designed to meet the electrical requirements of the negative electrode sheet 100.

[0089] In some embodiments, the thickness of the negative electrode active layer 120 is D2, 50 μm ≤ D2 ≤ 200 μm. The value of D2 can be 50 μm, 65 μm, 72 μm, 89 μm, 95 μm, 108 μm, 117 μm, 122 μm, 136 μm, 144 μm, 159 μm, 162 μm, 175 μm, 187 μm, 198 μm, 200 μm or other unspecified values. The thickness of the negative electrode active layer 120 is reasonably designed to meet the electrical requirements of the negative electrode sheet 100.

[0090] In some embodiments, the positive electrode sheet 200 includes a positive electrode current collector and a positive electrode active layer, and the positive electrode active layer is disposed on both sides of the positive electrode current collector. Exemplarily, the material of the positive electrode current collector may be aluminum foil, and the material of the positive electrode active layer may be one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt manganese oxide, and lithium iron phosphate.

[0091] See also Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 8 As shown, the embodiment of the present application also provides a method for preparing a thermal composite battery cell, which is used to prepare the thermal composite battery cell of any one of the above embodiments, comprising the following steps:

[0092] S10, providing N negative electrode sheets 100, M positive electrode sheets 200, a first separator 340 and a second separator 350, NM=1, wherein the N negative electrode sheets 100 include N-2 double-sided electrode sheets 100A and 2 single-sided electrode sheets 100B;

[0093] The negative electrode active layer 120 is disposed on both sides of the negative electrode current collector 110 of the double-sided electrode sheet 100A, and the negative electrode active layer 120 is disposed on one side of the negative electrode current collector 110 of the single-sided electrode sheet 100B;

[0094] S20, thermally compounding the double-sided electrode sheet 100A, the positive electrode sheet 200, the first separator 340 and the second separator 350 to form a composite laminate, see Figure 8 As shown, M positive electrode sheets 200 are arranged between the first separator 340 and the second separator 350 at intervals, the first separator 340 and the second separator 350 between adjacent positive electrode sheets 200 are thermally composited, the double-sided electrode sheets 100A are alternately arranged on the side of the first separator 340 away from the positive electrode sheet 200 and the side of the second separator 350 away from the positive electrode sheet 200, the double-sided electrode sheet 100A and the positive electrode sheet 200 are arranged in alignment, and an incompletely cut structure 330 is processed on the composite laminate, and the incompletely cut structure 330 is arranged on the first separator 340 and / or the second separator 350 between adjacent positive electrode sheets 200;

[0095] The number of the double-sided pole sheets 100A is one less than the number of the positive pole sheets 200, and the double-sided pole sheets 100A and the positive pole sheets 200 are arranged in alignment, including the following two situations: N-2 double-sided pole sheets 100A are arranged in alignment with the second to M-th positive pole sheets, or N-2 double-sided pole sheets 100A are arranged in alignment with the first to M-1-th positive pole sheets;

[0096] It can be understood that in this embodiment, after all the positive electrode sheets 200 are thermally composited with the first separator 340 and the second separator 350, all the double-sided electrode sheets 100A can be thermally composited, or the positive electrode sheets 200 and the negative electrode sheets 100 can be thermally composited with the first separator 340 and the second separator 350 alternately to form a composite laminate; the incompletely cut structure 330 can be processed after the composite laminate is completed, or the incompletely cut structure 330 can be processed after the single positive electrode sheet 200 is thermally composited, which is not specifically limited in this embodiment;

[0097] S30, fold the composite laminate along the straight line where the incompletely cut structure 330 is located to form a laminate unit, and thermally composite the two single-sided electrode sheets 100B on the outermost side of the laminate unit to prepare a thermal composite battery cell. Among them, the negative electrode active layer 120 of the negative electrode sheet 100 is laminated with the first separator 340 or the second separator 350.

[0098] In the present embodiment, the first separator 340, the second separator 350, the negative electrode sheet 100 and the positive electrode sheet 200 are thermally composited, and after the incompletely cut structure 330 is processed on the first separator 340 and / or the second separator 350, the composite laminate is free-fall folded along the incompletely cut structure 330. The stress on the first separator 340 and / or the second separator 350 at the incompletely cut structure 330 is small, so that the composite laminate is Z-folded along the straight line where the incompletely cut structure 330 is located, thereby achieving positioning folding and ensuring the alignment of the thermally composite battery cell.

[0099] In other embodiments, see Figure 5 and Figure 6 As shown, Figure 5 for Figure 2 The second form of AA section view, Figure 6 for Figure 5 A partial enlarged view of the B in the middle. The separator 300 is a single-layer separator, and the negative electrode sheet 100 and the positive electrode sheet 200 are respectively arranged on both sides of the separator 300, all the negative electrode sheets 100 are located on the same side of the separator 300, and all the positive electrode sheets 200 are located on the same side of the separator 300. Along the length direction of the separator 300, the negative electrode sheets 100 and the positive electrode sheets 200 are arranged at intervals, and an incomplete cutting structure 330 is arranged on the separator 300 between adjacent negative electrode sheets 100 and positive electrode sheets 200. The separator 300 is folded in a Z shape along the incomplete cutting structure 330, which ensures the alignment of the negative electrode sheets 100 and the positive electrode sheets 200 in the folded battery cell.

[0100] See also Figure 5 , Figure 6 and Figure 7 As shown, the embodiment of the present application also provides a method for preparing a thermal composite battery cell, which is used to prepare the thermal composite battery cell of the above embodiment, comprising the following steps:

[0101] S10, providing N negative electrode sheets 100, M positive electrode sheets 200 and a separator 300, NM=1, wherein the N negative electrode sheets 100 include N-2 double-sided electrode sheets 100A and 2 single-sided electrode sheets;

[0102] The negative electrode active layer 120 is disposed on both sides of the negative electrode current collector 110 of the double-sided electrode sheet 100A, and the negative electrode active layer 120 is disposed on one side of the negative electrode current collector 110 of the single-sided electrode sheet 100B;

[0103] It can be understood that the negative electrode sheet 100 and the positive electrode sheet 200 are obtained by cutting the negative electrode material roll and the positive electrode material roll respectively. During the preparation process, the required N negative electrode sheets 100 and M positive electrode sheets 200 can be cut completely, or each negative electrode sheet 100 or positive electrode sheet 200 can be cut to form a single negative electrode sheet 100 or positive electrode sheet 200 before thermal compounding;

[0104] S20, thermally compounding the double-sided electrode sheet 100A, the positive electrode sheet 200 and the separator 300 to form a composite laminate, see Fig. 9 As shown, all the double-sided pole sheets 100A are thermally composited on one side of the separator 300, and M positive pole sheets 200 are thermally composited on the other side of the separator 300. The double-sided pole sheets 100A and the positive pole sheets 200 are alternately arranged along the length direction Y of the separator 300, and N-2 double-sided pole sheets 100A are arranged between the first positive pole sheet 200 and the Mth positive pole sheet 200; an incompletely cut structure 330 is processed on the composite laminate, and the incompletely cut structure 330 is arranged on the separator 300 between the negative pole sheet 100 and the positive pole sheet 200;

[0105] It can be understood that the diaphragm 300 is a layer of diaphragm, all the double-sided electrode sheets 100A are thermally composited on one side of the diaphragm 300, and M positive electrode sheets 200 are thermally composited on the other side of the diaphragm 300, and the gaps between adjacent negative electrode sheets 100 and positive electrode sheets 200 are the same; the incompletely cut structure 330 can be uniformly processed on the diaphragm 300 after the composite lamination process is completed, and the incompletely cut structure 330 can also be processed on the diaphragm 300 after the single negative electrode sheet 100 or the single positive electrode sheet 200 is processed;

[0106] S30, folding the composite laminate in a Z shape along the straight line where the incompletely cut structure 330 is located to form a laminate unit, and thermally compounding the two single-sided pole pieces 100B on the outermost sides of the laminate unit, wherein the negative electrode active layer 120 of the single-sided pole piece 100B is bonded to the separator 300 to prepare a thermally compounded battery cell.

[0107] In the present embodiment, the diaphragm 300, the negative electrode sheet 100 and the positive electrode sheet 200 are thermally composited, and after the incompletely cut structure 330 is processed on the diaphragm 300, the composite laminate is free-fall folded along the incompletely cut structure 330. The diaphragm 300 at the incompletely cut structure 330 is subjected to less stress during the folding process, so that the composite laminate is Z-folded along the straight line where the incompletely cut structure 330 is located, and the folding efficiency is high and the folding quality is good.

[0108] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0109] In the description of this application, 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 technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0110] The thermal composite battery cell provided in the embodiments of the present application is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technicians in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A thermal composite battery cell, characterized in that: include: N negative electrode sheets (100), N being a positive integer greater than 1, and each negative electrode sheet (100) being provided with a negative electrode tab (130); M positive electrode sheets (200), M is a positive integer greater than 1, and NM=1, and a positive electrode tab (210) is provided on the positive electrode sheet (200); A diaphragm (300), the diaphragm (300) comprising a plurality of main bodies (310) and a plurality of bending parts (320) arranged alternately and continuously, wherein, along the thickness direction of the negative electrode sheet (100), the negative electrode sheet (100) and the positive electrode sheet (200) are alternately stacked, the adjacent negative electrode sheet (100) and the positive electrode sheet (200) are separated by the main body (310), the bending part (320) is provided with an incompletely cut structure (330), the diaphragm (300) is folded along the incompletely cut structure (330), and at least part of the structure of the negative electrode tab (130) and the positive electrode tab (210) is located outside the diaphragm (300); The two negative electrode sheets (100) located on the outermost sides are single-sided electrode sheets (100B), and the other negative electrode sheets (100) are double-sided electrode sheets (100A).

2. The thermal composite battery cell according to claim 1, characterized in that: The single-sided electrode sheet (100B) comprises a negative electrode current collector (110) and a negative electrode active layer (120), and the negative electrode active layer (120) is arranged on a side of the negative electrode current collector (110) close to the main body (310); And / or, the double-sided electrode sheet (100A) comprises a negative electrode current collector (110) and a negative electrode active layer (120), and the negative electrode active layer (120) is provided on both sides of the negative electrode current collector (110).

3. The thermal composite battery cell according to claim 1, characterized in that: The diaphragm (300) includes a first diaphragm (340) and a second diaphragm (350), wherein the first diaphragm (340) includes a first main body portion (311) and a first bending portion (321), and the second diaphragm (350) includes a second main body portion (312) and a second bending portion (322), and the first bending portion (321) and / or the second bending portion (322) are provided with the incompletely cut structure (330).

4. The thermal composite battery cell according to claim 3, characterized in that: The first bending portion (321) and the second bending portion (322) are both provided with the incompletely cut structure (330), and the projection of the incompletely cut structure (330) on the first bending portion (321) on the second diaphragm (350) overlaps with the incompletely cut structure (330) on the second bending portion (322).

5. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The incompletely cut structure (330) comprises a plurality of through holes (331) penetrating the diaphragm (300), and the plurality of through holes (331) are arranged at intervals along the width direction of the diaphragm (300).

6. The thermal composite battery cell according to claim 5, characterized in that: The intervals between adjacent through holes (331) are the same.

7. The thermal composite battery cell according to claim 5, characterized in that: The through hole (331) is in a circular or rectangular shape.

8. The thermal composite battery cell according to claim 5, characterized in that: Along the width direction of the diaphragm (300), the interval between adjacent through holes (331) is S1, wherein 5 mm ≤ S1 ≤ 20 mm.

9. The thermal composite battery cell according to claim 5, characterized in that: The through hole (331) has a first size L1 and a second size W1, wherein the first size is the distance between two parallel planes that virtually abut the hole walls at both sides of the through hole (331), and the second size is the distance between two parallel planes that virtually abut the hole walls at both ends of the through hole (331), wherein 1mm≤L1≤20mm, and / or 1mm≤W1≤2mm.

10. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The long side dimension of the negative electrode sheet (100) is greater than the long side dimension of the positive electrode sheet (200), and the wide side dimension of the negative electrode sheet (100) is greater than the wide side dimension of the positive electrode sheet (200).

11. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The distance between the long side of the positive electrode sheet (200) and the long side of the negative electrode sheet (100) is S2, 1mm≤S2≤3mm; And / or, the distance between the wide side of the positive electrode sheet (200) and the wide side of the negative electrode sheet (100) is S3, 1mm≤S3≤3mm.

12. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The long side dimension of the main body (310) is greater than the long side dimension of the negative electrode sheet (100), and the wide side dimension of the main body (310) is greater than the wide side dimension of the negative electrode sheet (100).

13. The thermal composite battery cell according to claim 12, characterized in that: The distance between the long side of the negative electrode sheet (100) and the long side of the separator (300) is S4, wherein 2 mm ≤ S4 ≤ 4 mm; And / or, the separator (300) comprises a starting end (360), and the distance between the starting end (360) and the wide side of the negative electrode sheet (100) close to the starting end (360) is S5, wherein 1 mm≤S5≤3 mm.

14. The thermal composite battery cell according to claim 2, characterized in that: The thickness of the negative electrode current collector (110) is D1, 4 μm≤D1≤6 μm; And / or, the thickness of the negative electrode active layer (120) is D2, 50 μm≤D2≤200 μm.

15. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The positive electrode sheet (200) comprises a positive electrode current collector and a positive electrode active layer, and the positive electrode active layer is disposed on both sides of the positive electrode current collector.

16. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: The negative electrode sheet (100), the positive electrode sheet (200) and the separator (300) are thermally composite-connected.

17. The thermal composite battery cell according to any one of claims 1 to 4, characterized in that: Along the thickness direction of the negative electrode sheet (100), the projections of all the negative electrode tabs (130) overlap, and / or the projections of all the positive electrode tabs (210) overlap.

18. The thermal composite battery cell according to claim 17, characterized in that: The projections of the negative electrode tab (130) and the positive electrode tab (210) in the plane where the main body (310) is located are arranged side by side.

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