Laminated battery cell

Abstract

The utility model discloses a laminated battery cell, the battery cell comprises a plurality of first pole pieces, a plurality of second pole pieces and a diaphragm, the polarity of the first pole pieces is opposite to that of the second pole pieces, the first pole pieces are provided with first tabs, the second pole pieces are provided with second tabs, and the diaphragm comprises a plurality of main body parts and a plurality of bent parts which are alternately and continuously arranged; wherein the first pole pieces and the second pole pieces are alternately stacked along the thickness direction of the first pole pieces, the adjacent first pole pieces and second pole pieces are separated by the main body parts, the bending parts are provided with incompletely cut structures, the diaphragms are folded at the incompletely cut structures, and at least partial structures of the first pole lugs and the second pole lugs are positioned on the diaphragms. The diaphragm can be continuously folded in a Z shape along the straight line where the incompletely cut part is located, the alignment degree of the prepared laminated battery cell is good, lithium precipitation is reduced, and the electrical performance of the laminated battery cell is improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular to laminated 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 pole pieces and the 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 pieces and embedded in the negative pole pieces. Due to the misalignment of the positive pole pieces and the negative pole pieces, the lithium ions cannot be completely embedded in the negative pole pieces. The lithium ions that cannot be embedded in the negative pole pieces can only obtain electrons on the surface of the negative pole pieces, thereby forming white metallic lithium and causing lithium plating. 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, 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 incomplete cutting structure on the bent portion of the diaphragm, and the diaphragm is folded along the incomplete cutting structure.

[0005] In a first aspect, an embodiment of the present application provides a laminated battery cell, comprising: a plurality of first pole sheets, each of which is provided with a first pole lug;

[0006] a plurality of second pole pieces, each of which is provided with a second pole lug, and the first pole piece and the second pole piece have opposite polarities; and

[0007] A diaphragm, the diaphragm comprising a plurality of main body portions and a plurality of bending portions arranged alternately and continuously;

[0008] Among them, along the thickness direction of the first pole sheet, the first pole sheet and the second pole sheet are alternately stacked, the adjacent first pole sheet and the second pole sheet are separated by the main body, the bending portion is provided with an incompletely cut structure, the diaphragm is folded at the incompletely cut structure, and the first pole ear and the second pole ear have at least partial structures located on the outside of the diaphragm.

[0009] Optionally, the diaphragm includes a first diaphragm and a second diaphragm, the first diaphragm includes a first main body and a first bending portion, the second diaphragm includes a second main body and a second bending portion, and the first bending portion and / or the second bending portion are provided with the incompletely cut structure.

[0010] 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.

[0011] Optionally, the bent portion of the first diaphragm is fitted and connected to the bent portion of the second diaphragm.

[0012] 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.

[0013] Optionally, the intervals between any two adjacent through holes are the same.

[0014] Optionally, along the width direction of the diaphragm, an interval between adjacent through holes is S1, wherein 5 mm ≤ S1 ≤ 20 mm.

[0015] 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.

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

[0017] Optionally, the first pole piece and the second pole piece have opposite polarities.

[0018] Optionally, the first pole piece is a negative pole piece or a positive pole piece, and the second pole piece is a positive pole piece or a negative pole piece.

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

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

[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, wherein 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 plate and the long side of the separator is S4, wherein 2 mm ≤ S4 ≤ 4 mm;

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

[0025] Optionally, it includes N first pole pieces and M second pole pieces, N and M are both positive integers greater than 1, and when the first pole piece is a negative pole piece and the second pole piece is a positive pole piece, NM=1.

[0026] Optionally, the diaphragm includes a starting end and an ending end, the first first pole piece is closer to the starting end of the diaphragm than the first second pole piece, and the Nth first pole piece is closer to the ending end of the diaphragm than the Mth second pole piece.

[0027] Optionally, it includes N first pole pieces and M second pole pieces, N and M are both positive integers greater than 1, and when the first pole piece is a positive pole piece and the second pole piece is a negative pole piece, MN=1.

[0028] Optionally, the diaphragm includes a starting end and an ending end, the first second pole piece is closer to the starting end of the diaphragm than the first first pole piece, and the Mth second pole piece is closer to the ending end of the diaphragm than the Nth first pole piece.

[0029] Optionally, along the thickness direction of the first pole piece, the projections of all the first pole tabs overlap, and / or the projections of all the second pole tabs overlap.

[0030] Optionally, the projections of the first pole lug and the second pole lug in the plane where the main body is located are arranged side by side.

[0031] The stacked battery cell provided in the embodiment of the present application includes a plurality of first pole sheets, a plurality of second pole sheets and a diaphragm, the diaphragm includes a main body and a bending portion, adjacent main bodies are connected by the bending portions, and an incompletely cut structure is provided on each bending portion. The first pole sheets and the second pole sheets are alternately stacked along the thickness direction of the first pole sheets, and a main body is provided on both sides of each first pole sheet. Adjacent first pole sheets and second pole sheets are separated by the main body to avoid short circuit caused by electrical connection between the first pole sheet and the second pole sheet. The diaphragm is not completely cut, and the diaphragm can be continuously folded 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, the alignment of the stacked battery cell is good, the occurrence of lithium plating is reduced, and the electrical performance of the stacked battery cell in terms of cycle life, fast charging capacity and safety is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. The drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained 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 foldable battery cell provided in an embodiment of the present application having a double-layer separator and a negative electrode plate located between the two layers of separators.

[0035] Figure 2 for Figure 1 Top view of the .

[0036] Figure 3 for Figure 2 Middle AA section view.

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

[0038] Figure 5 A cross-sectional schematic diagram of a foldable battery cell provided in an embodiment of the present application having a double-layer separator and a negative electrode plate located between the two layers of separators before folding.

[0039] Figure 6 A three-dimensional diagram of a foldable battery cell provided in an embodiment of the present application having a double-layer separator and a positive electrode sheet located between the separators on both sides.

[0040] Figure 7 A cross-sectional view of a foldable battery cell provided in an embodiment of the present application having a double-layer separator and a positive electrode sheet located between the separators on both sides.

[0041] Figure 8 for Figure 7 A partial enlarged view of point C in the middle.

[0042] Fig. 9 A cross-sectional schematic diagram of a foldable battery cell provided in an embodiment of the present application having a double-layer separator and a positive electrode sheet located between the separators on both sides before folding.

[0043] Fig.10 for Fig. 9 A partial enlarged view of point E in the middle.

[0044] Fig.11 A top view of the laminated battery cell provided in an embodiment of the present application before folding.

[0045] Fig.12 A three-dimensional diagram of a foldable battery cell provided in an embodiment of the present application with a single-layer diaphragm.

[0046] Fig.13 A cross-sectional schematic diagram of a foldable battery cell provided in an embodiment of the present application with a single-layer diaphragm.

[0047] Fig.14 for Fig.13 A partial enlarged view of point D in the middle.

[0048] Fig.15 A schematic cross-sectional view of a foldable battery cell provided in an embodiment of the present application having a single-layer separator before folding. DETAILED DESCRIPTION

[0049] 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 a part of the embodiments of the present application, rather than all of the embodiments. Based on the described embodiments, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0050] The laminated battery cell of the embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0051] See also Figure 1 , Figure 2 and Figure 3 As shown, the embodiment of the present application provides a laminated battery cell 10, comprising a plurality of first pole pieces 100, a plurality of second pole pieces 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.

[0052] In this embodiment, the first pole piece 100 and the second pole piece 200 are cut from the first pole piece roll and the second pole piece roll. The shapes of the first pole piece 100 and the second pole piece 200 can both be rectangular. A first pole ear 110 can be provided on the first pole piece 100, and a second pole ear 210 can be provided on the second pole piece 200. The first pole ear 110 and the second pole ear 210 can both have at least a partial structure located outside the diaphragm 300. The polarity of the first pole piece 100 is opposite to that of the second pole piece 200, the first pole ear 110 has the same polarity as the first pole piece 100, and the second pole ear 210 has the same polarity as the second pole piece 200. For example: the first pole ear 110 and the first pole piece 100 are both positive electrodes, and the second pole ear 210 and the second pole piece 200 are both negative electrodes; or the first pole ear 110 and the first pole piece 100 are both negative electrodes, and the second pole ear 210 and the second pole piece 200 are both positive electrodes.

[0053] In some embodiments, see Figure 1 , Figure 2 and Figure 3 As shown, along the thickness direction X of the first pole piece 100, the projections of all the first pole tabs 110 overlap, and the projections of all the second pole tabs 210 overlap. The first pole tabs 110 are stacked with the first pole piece 100, and the second pole tabs 210 are stacked with the second pole piece 200. The adjacent first pole tabs 110 are spaced apart by the thickness of a main body 310, and the projections of all the first pole tabs 110 are at the same position, and the adjacent second pole tabs 210 are spaced apart by the thickness of a main body 310, and the projections of all the second pole tabs 210 are at the same position, so that all the first pole tabs 110 are welded together, all the second pole tabs 210 are welded together, and the first pole tabs 110 and the second pole tabs 210 occupy a small space.

[0054] In some embodiments, see Figure 2 As shown, the projections of the first pole lug 110 of the first pole piece 100 and the second pole lug 210 on the second pole piece 200 in the plane where the main body 310 is located are arranged side by side. The first pole piece 100 and the second pole piece 200 are located on both sides of the main body 310, respectively. The projections of the first pole lug 110 on the first pole piece 100 and the second pole lug 210 on the second pole piece 200 in the plane where the main body 310 is located are arranged at intervals to prevent the first pole lug 110 from interfering with the second pole lug 210, thereby ensuring electrical safety.

[0055] In some embodiments, see Figure 1 , Figure 2 and Figure 3As shown, the diaphragm 300 is a continuous diaphragm, and the diaphragm 300 includes a plurality of main parts 310 and a plurality of bending parts 320 that are alternately and continuously arranged. The plurality of main parts 310 are stacked along the thickness direction X of the first pole piece 100, and two adjacent main parts 310 are connected by the bending parts 320. The bending parts 320 are provided with an incompletely cut structure 330, and the diaphragm 300 is bent at the incompletely cut structure 330.

[0056] In some embodiments, see Figure 3 As shown, along the thickness direction of the first pole piece 100, the first pole piece 100 and the second pole piece 200 are alternately stacked, and the adjacent first pole pieces 100 and second pole pieces 200 are separated by the main body 310. The projections of the first pole piece 100 and the second pole piece 200 along the thickness direction of the first pole piece 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 first pole piece 100 and the second pole piece 200, and prevent the first pole piece 100 and the second pole piece 200 from contacting 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 first pole piece 100.

[0057] It can be understood that before folding, the diaphragm 300 is in a continuous strip structure, the first pole piece 100 and the second pole piece 200 are compounded on the main body 310 of the diaphragm 300 to form a composite laminate, an incompletely cut structure 330 is provided on the diaphragm 300, the distance between the two sides of the incompletely cut structure 330 and the first pole piece 100 on the side thereof is 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, and the size between the folding positions is the same, which improves the alignment during the folding process, avoids the situation where lithium deposition pierces the diaphragm 300 due to the misalignment of the first pole piece 100 and the second pole piece 200, and improves the electrical performance of the folded battery cell.

[0058] Among them, the first electrode sheet 100 and the second electrode sheet 200 are compounded on the diaphragm 300, which means that the first electrode sheet 100 and the second electrode sheet 200 are fixed on the surface of the diaphragm 300 through a thermal compound process. Exemplarily, the thermal compound process is as follows: the positive electrode material roll, the negative electrode material roll, and the diaphragm are fed at the same time. Before entering the heating device, the positive electrode sheet and the negative electrode sheet are cut into single electrode sheets of the required size by a cutter. The combination of the positive electrode sheet, the negative electrode sheet, and the diaphragm enters the heating system under the action of the roller. The diaphragm is a glue-coated diaphragm, which is sticky after heating. The baked positive electrode sheet, the negative electrode sheet and the diaphragm 300 are thermally compounded, and then rolled and cut to form a composite laminate.

[0059] In some embodiments, see Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figure 8 As shown, the number of the diaphragms 300 can be multiple, and the multiple diaphragms can be stacked along the thickness direction of the first pole piece 100. Exemplarily, the battery cell can include a double-layer diaphragm, or can include more layers of diaphragms. The embodiment of the present application is described by taking a double-layer diaphragm as an example, and the embodiments of diaphragms with other layers can be adaptively designed based on the embodiment of the double-layer diaphragm.

[0060] In some embodiments, see Figure 1 and Figure 3 As shown, the double-layer diaphragm 300 includes a first diaphragm 340 and a second diaphragm 350, and the first diaphragm 340 and the second diaphragm 350 both include a main body 310 and a bending portion 320. Along the thickness direction X of the first pole piece 100, the first pole piece 100 and the second pole piece 200 are alternately stacked, and the adjacent first pole pieces 100 and the second pole pieces 200 are separated by the main body 310. The bending portion 320 of the first diaphragm 340 is provided with an incompletely cut structure 330 and / or the bending portion 320 of the second diaphragm 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.

[0061] For example, see 1. Figure 2 , Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figure 8As shown, the battery cell may include a double 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 first pole piece 100 is provided between any two adjacent first main bodies 311 and second main bodies 312, and a second pole piece 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.

[0062] Exemplarily, 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 the structure 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.

[0063] In this embodiment, see Figure 5 As shown, before folding, the first diaphragm 340 and the second diaphragm 350 are both continuous strip structures. The first pole piece 100 is compounded between the first diaphragm 340 and the second diaphragm 350. The second pole piece 200 is compounded on the side of the first diaphragm 340 away from the first pole piece 100 and the side of the second diaphragm 350 away from the first pole piece 100. The incompletely cut structure 330 is located between adjacent first pole pieces 100, and the distance between the two sides of the incompletely cut structure 330 is the same as the distance between the first pole piece 100 on its side. 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 a role in limiting the folding position and improving the folding quality and folding efficiency.

[0064] The embodiment of the present application limits the folding position of the diaphragm 300 by setting an incomplete cutting portion, so that the diaphragm 300 can be folded at basically the same position to ensure the alignment of the first pole piece 100 and the second pole piece 200 in the folded battery cell, and reduce the occurrence of lithium plating piercing the diaphragm 300 due to the misalignment of the first pole piece 100 and the second pole piece 200, thereby improving the electrical performance of the folded battery cell in terms of service life, fast charging capacity, safety, etc.

[0065] In some embodiments, see Figure 1 , Figure 4 , Figure 6 , Figure 8 , Fig. 9 and Fig.10 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 Z 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.

[0066] 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. In addition, the incompletely cut structure 330 may also be a reticular structure.

[0067] 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 penetrating the first diaphragm 340, and the incompletely cut structure 330 on the second diaphragm 350 is a through hole 331 penetrating the second diaphragm 350. When both the first diaphragm 340 and the second diaphragm 350 are provided with the incompletely cut structure 330, the through hole 331 on the first diaphragm 340 and the through hole 331 on the second diaphragm 350 are arranged opposite to each other, and the through hole 331 on the first diaphragm 340 and the through hole 331 on the second diaphragm 350 penetrate each other.

[0068] It can be understood that by providing a plurality of through holes 331 in the diaphragm 300 to form an incompletely cut structure 330, local material on the diaphragm 300 is cut off, and along the width direction Z of the diaphragm 300, the diaphragm 300 is not completely cut, so that the diaphragm 300 around the through holes 331 is weak. When free fall folding is performed, the diaphragm 300 will fold along the position of the through holes 331, realizing precise position folding, which is beneficial to the alignment of the first pole piece 100 and the second pole piece 200 in the folded battery cell.

[0069] In some embodiments, the intervals between adjacent through holes 331 are the same, wherein 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 .

[0070] 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 situation where the local strength is weak and it is broken during the folding process.

[0071] In some embodiments, the through hole 331 is in a regular shape such as a circle, a rectangle, an ellipse, a hexagon, or an octagon. In addition to being in a regular shape, the through hole 331 can also be in an irregular shape.

[0072] In some embodiments, see Fig.10 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.

[0073] 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.

[0074] In some embodiments, see Fig.10As 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.

[0075] 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.

[0076] 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.

[0077] In some embodiments, the first electrode sheet 100 is a negative electrode sheet or a positive electrode sheet, and the second electrode sheet 200 is a positive electrode sheet or a negative electrode sheet.

[0078] For example, see Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, if the first electrode 100 is a negative electrode, correspondingly, the second electrode 200 is a positive electrode; see Figure 6 , Figure 7 and Figure 8As shown, if the first pole piece 100 is a positive pole piece, correspondingly, the second pole piece 200 is a negative pole piece.

[0079] In some embodiments, see Figure 3 , Figure 7 , Fig.10 As shown, the length dimension of the negative electrode sheet is greater than the length dimension of the positive electrode sheet, and the width dimension of the negative electrode sheet is greater than the width dimension of the positive electrode sheet. In the laminated battery cell, along the thickness direction of the negative electrode sheet, the projection of the positive electrode sheet on the negative electrode sheet completely falls into the negative electrode sheet.

[0080] Understandably, see Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, if the first electrode 100 is a negative electrode and the second electrode 200 is a positive electrode, the length dimension of the first electrode 100 is greater than the length dimension of the second electrode 200, and the width dimension of the first electrode 100 is greater than the width dimension of the second electrode 200; see Figure 6 , Figure 7 and Figure 8 As shown, if the first pole piece 100 is a positive pole piece and the second pole piece 200 is a negative pole piece, the length dimension of the first pole piece 100 is smaller than the length dimension of the second pole piece 200, and the width dimension of the first pole piece 100 is smaller than the width dimension of the second pole piece 200. The size of the negative pole piece is designed to be larger than the size of the positive pole piece. During the charging process of the lithium battery, the negative pole piece can completely receive the lithium ions of the positive pole piece, reducing the probability of lithium dendrite formation, thereby reducing the occurrence of the situation where the diaphragm 300 is pierced by the formation of lithium dendrites, resulting in the occurrence of thermal runaway caused by short circuit, thereby improving the reliability of the battery.

[0081] In some embodiments, see Fig.10 As shown, the distance between the long side of the positive electrode sheet and the long side of the negative electrode sheet is S2, where 1mm≤S2≤3mm, and / or the distance between the wide side of the positive electrode sheet and the wide side of the negative electrode sheet is S3, where 1mm≤S3≤3mm. The values ​​of S2 and S3 can be 1mm, 1.3mm, 1.7mm, 1.8mm, 2.0mm, 2.3mm, 2.7mm, 3.0mm or other unspecified values.

[0082] Among them, the distance S2 between the long side of the positive electrode sheet and the long side of the negative electrode sheet and the distance S3 between the wide side of the positive electrode sheet and the wide side of the negative electrode sheet can be the same or different, and this embodiment does not make specific limitations.

[0083] In the embodiments of the present application, the distance S2 between the long side of the positive electrode sheet and the long side of the negative electrode sheet and the distance S3 between the wide side of the positive electrode sheet and the wide side of the negative electrode sheet are reasonably designed. Under the premise of meeting the safety performance of the battery, due to the good alignment of the stacked battery cells, the size of the negative electrode sheet exceeding the positive electrode sheet can be appropriately shortened, the material of the negative electrode sheet can be reduced, and the cost can be reduced.

[0084] In some embodiments, see Fig.10 As shown, the long side dimension of the main body 310 is larger than the long side dimension of the negative electrode sheet, and the wide side dimension of the main body 310 is larger than the wide side dimension of the negative electrode sheet, that is, the projection of the negative electrode sheet on the main body 310 completely falls into the continuous surface area enclosed by the outer contour of the main body 310.

[0085] The negative electrode sheet and the positive electrode sheet are separated by the main body 310. If the size of the main body 310 is smaller than the size of the negative electrode sheet, the negative electrode sheet and the positive electrode sheet 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 size of the positive electrode sheet to meet the electrical safety requirements of the laminated battery cell and improve the reliability of the laminated battery cell.

[0086] In some embodiments, see Fig.10 As shown, the distance between the long side of the negative electrode sheet 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 closest to the starting end 360 is S5, where 1mm≤S5≤3mm. The long side of the negative electrode sheet refers to the side extending along the Z direction, and the wide side of the negative electrode sheet refers to the side extending along the Y direction.

[0087] 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.

[0088] 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.

[0089] In this embodiment, the values ​​of S4 and S5 may be the same or different, and this embodiment does not make any specific limitation.

[0090] It can be understood that the dimensions of the negative electrode plate 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.

[0091] In some embodiments, see Figure 4 As shown, the laminated battery cell includes N first pole sheets 100 and M second pole sheets 200 , where N and M are both positive integers greater than 1. When the first pole sheet 100 is a negative pole sheet and the second pole sheet 200 is a positive pole sheet, NM=1.

[0092] It can be understood that the first electrode sheets 100 and the second electrode sheets 200 are arranged alternately, and the number of negative electrode sheets is one more than that of positive electrode sheets. The two outermost electrode sheets of the stacked battery cell are both negative electrode sheets, ensuring that the negative electrode sheets can provide sufficient vacancies for the lithium ions escaped from the positive electrode sheets to embed, and providing excess negative electrode sheets to reduce the probability of surface lithium branched crystals in the battery, thereby meeting the electrical requirements of the battery.

[0093] Based on the above implementation, see Figure 4 As shown, the diaphragm 300 includes a starting end 360 and an ending end 370 , the first first pole piece 100 is closer to the starting end 360 of the diaphragm 300 than the first second pole piece 200 , and the Nth first pole piece 100 is closer to the ending end 370 of the diaphragm 300 than the Mth second pole piece 200 .

[0094] It can be understood that along the thickness direction of the first electrode sheet 100, N first electrode sheets 100 and M second electrode sheets 200 are alternately arranged, from the bottom to the top of the stacked battery cell, the N first electrode sheets 100 are sequentially the 1st first electrode sheet 100 to the Nth first electrode sheet 100, and the M second electrode sheets 200 are sequentially the 1st second electrode sheet 200 to the Mth second electrode sheet 200, the bottom and top of the stacked battery cell are the 1st first electrode sheet 100 and the Nth first electrode sheet 100 respectively, the diaphragm 300 wraps the side of the 1st first electrode sheet 100 away from the 1st second electrode sheet 200, and the diaphragm 300 wraps the side of the Nth first electrode sheet 100 away from the Mth second electrode sheet 200.

[0095] In some embodiments, see Figure 7 As shown, the laminated battery cell includes N first pole sheets 100 and M second pole sheets 200 , where N and M are both positive integers greater than 1. When the first pole sheet 100 is a positive pole sheet and the second pole sheet 200 is a negative pole sheet, MN=1.

[0096] It can be understood that the first pole sheets 100 and the second pole sheets 200 are arranged alternately, and the number of negative pole sheets is one more than the number of positive pole sheets, and the two outermost pole sheets of the laminated battery cell are both negative pole sheets, which meets the electrical requirements of the battery.

[0097] Based on the above implementation, see Figure 7 and Figure 8As shown, the diaphragm 300 includes a starting end 360 and an ending end 370 . The first second pole piece 200 is closer to the starting end 360 of the diaphragm 300 than the first first pole piece 100 , and the Mth second pole piece 200 is closer to the ending end 370 of the diaphragm 300 than the Nth first pole piece 100 .

[0098] It can be understood that along the thickness direction of the first electrode sheet 100, N first electrode sheets 100 and M second electrode sheets 200 are alternately arranged, from the bottom to the top of the stacked battery cell, the N first electrode sheets 100 are sequentially the 1st first electrode sheet 100 to the Nth first electrode sheet 100, and the M second electrode sheets 200 are sequentially the 1st second electrode sheet 200 to the Mth second electrode sheet 200, the bottom and top of the stacked battery cell are the 1st second electrode sheet 200 and the Nth second electrode sheet 200, respectively, the diaphragm 300 wraps the side of the first second electrode sheet 200 away from the first first electrode sheet 100, and the diaphragm 300 wraps the side of the Mth second electrode sheet 200 away from the Nth first electrode sheet 100.

[0099] The present application also provides a method for preparing a laminated battery cell, which is used for the laminated battery cell 10 of any one of the above embodiments, and comprises the following steps:

[0100] S10, providing a first pole piece 100, a second pole piece 200, a first diaphragm 340 and a second diaphragm 350;

[0101] S20, the first pole piece 100, the second pole piece 200, the first diaphragm 340 and the second diaphragm 350 are thermally combined to form a composite laminate, wherein a plurality of first pole pieces 100 are arranged between the first diaphragm 340 and the second diaphragm 350 at intervals, the second pole pieces 200 are alternately arranged on a side of the first diaphragm 340 away from the first pole piece 100 and on a side of the second diaphragm 350 away from the first pole piece 100, and the position of the second pole piece 200 corresponds to the position of the first pole piece 100; an incompletely cut structure 330 is processed on the composite laminate, and the incompletely cut structure 330 is arranged on the first diaphragm 340 and / or the second diaphragm 350 between adjacent first pole pieces 100;

[0102] Understandably, see Figure 1 , Figure 3 and Figure 5 As shown, when the first electrode 100 is a negative electrode, the corresponding second electrode 200 is a positive electrode, and the structure of the composite laminate formed by thermally combining the first electrode 100, the second electrode 200, the first diaphragm 340 and the second diaphragm 350 is as shown in FIG. Figure 5 shown; see Figure 6 , Figure 7 and Fig.11As shown, when the first electrode 100 is a positive electrode, the corresponding second electrode 200 is a negative electrode, and the structure of the composite laminate formed by thermally compounding the first electrode 100, the second electrode 200, the first diaphragm 340 and the second diaphragm 350 is as shown in FIG. Fig.11 As shown;

[0103] S30 , folding the composite laminate in a Z-shape along the straight line where the incompletely cut structure 330 is located, to form a laminated battery core 10 .

[0104] It can be understood that in this embodiment, the first diaphragm 340 and the second diaphragm 350, the first pole piece 100 and the second pole piece 200 are thermally composited, and after the incompletely cut structure 330 is processed on the first diaphragm 340 and / or the second diaphragm 350, the composite laminate is free-fall folded along the incompletely cut structure 330. The first diaphragm 340 and / or the second diaphragm 350 at the incompletely cut structure 330 is subjected to less stress, so that the composite laminate is Z-folded along the straight line where the incompletely cut structure 330 is located, thereby improving the folding efficiency and folding quality and ensuring the alignment of the laminated battery cells.

[0105] In some embodiments, see Fig.10 As shown, on the composite laminate, the distance between the incompletely cut structure 330 and the first pole pieces 100 on both sides is the same. Among them, the distance between the incompletely cut structure 330 and the first pole pieces 100 on both sides refers to the distance between the plane where the side edge of the incompletely cut structure 330 is located and the side of the first pole piece 100 on its side. On the composite laminate, the distances between adjacent first pole pieces 100 are the same, and the distances between the incompletely cut structure 330 and the first pole pieces 100 on both sides are the same. The folding position is determined. After the first pole pieces 100 are stacked, the two side edges of all the first pole pieces 100 are aligned. Correspondingly, the second pole pieces 200 compounded on the diaphragm 300 on one side of the first pole piece 100 are also aligned, and the second pole pieces 200 must all fall into the first pole piece 100, thereby improving the alignment of the laminated battery cell. It can be understood that the same distance in this embodiment includes approximately the same distance and the same distance within the range of processing error.

[0106] In some embodiments, see Fig.10 As shown, on the composite laminate, the distance S6 between the incompletely cut structure 330 and the adjacent first pole piece 100 is 2.0 mm≤S6≤4.0 mm.

[0107] For example, the value of S5 may be 2.0 mm, 2.1 mm, 2.8 mm, 3.2 mm, 3.5 mm, 3.9 mm, 4.0 mm or other unspecified values. The parameter design of S5 is reasonable to ensure that the diaphragm 300 can be folded along the incompletely cut structure 330, so that the diaphragm 300 can cover the corresponding negative electrode plate to ensure the electrical safety of the battery cell.

[0108] In some embodiments, see Figure 5 As shown, the composite stack includes N first pole pieces 100 and M second pole pieces 200. When the first pole piece 100 is a negative pole piece and the second pole piece 200 is a positive pole piece, NM=1, wherein the diaphragm 300 includes a starting end 360 and an ending end 370. From the starting end 360 to the ending end 370, the position of the i-th second pole piece 200 corresponds to the position of the i-th first pole piece 100, wherein i is a positive integer from 1 to M. Figure 5 As shown, from the starting end 360 to the ending end 370, the N first pole pieces 100 are sequentially the 1st first pole piece 100, the 2nd first pole piece 100 to the Nth first pole piece 100, and the M second pole pieces 200 are sequentially the 1st second pole piece 200, the 2nd second pole piece 200 to the Mth second pole piece 200. It can be seen that the second pole piece 200 is not provided at the corresponding position of the Nth first pole piece 100.

[0109] In the examples of this application, see Figure 5 As shown, the first pole piece 100 and the first second pole piece 200 of the composite stack are fixed, the second first pole piece 100 and the second second pole piece 200 are folded clockwise, and the third first pole piece 100 and the third second pole piece 200 are folded counterclockwise, and a stacked battery cell is prepared by reciprocating Z-shaped folding in this way, ensuring that the pole pieces on the outermost sides of the stacked battery cell are both negative pole pieces, meeting the electrical requirements, and combining reasonable design.

[0110] In some embodiments, see Fig.11 As shown, the composite stack includes N first pole pieces 100 and M second pole pieces 200. When the first pole piece 100 is a positive pole piece and the second pole piece 200 is a negative pole piece, MN=1, wherein the diaphragm 300 includes a starting end 360 and an ending end 370. From the starting end 360 to the ending end 370, the position of the i-th second pole piece 200 corresponds to the position of the i-th first pole piece 100, wherein i is a positive integer from 1 to N. Fig.11 As shown, from the starting end 360 to the ending end 370, the N first pole pieces 100 are sequentially the 1st first pole piece 100, the 1st first pole piece 100 to the Nth first pole piece 100, and the M second pole pieces 200 are sequentially the 1st second pole piece 200, the 2nd second pole piece 200 to the Mth second pole piece 200. It can be seen that the first pole piece 100 is not provided at the corresponding position of the Mth second pole piece 200.

[0111] In an embodiment of the present application, the first second pole piece 200 and the first first pole piece 100 near the starting end 360 in the composite stack are fixed, the second first pole piece 100 and the second second pole piece 200 are folded clockwise first, and then the unit of the second first pole piece 100 and the second second pole piece 200 is folded counterclockwise, and a stacked battery cell is prepared by such reciprocating Z-shaped folding, ensuring that the pole pieces on the outermost sides of the stacked battery cell are both negative pole pieces, meeting the electrical requirements, and combining reasonable design.

[0112] See also Fig.12 , Fig.13 and Fig.14 As shown, the embodiment of the present application also provides a stacked battery cell, which is different from other embodiments in that: the diaphragm 300 in the present embodiment is a single-layer diaphragm, the diaphragm 300 has multiple main parts 310 and multiple bending parts 320, one side of the first pole piece 100 is compounded with one side of the diaphragm 300, one side of the second pole piece 200 is compounded with the other side of the diaphragm 300, the adjacent first pole piece 100 and second pole piece 200 are separated by the main part 310, and the incomplete cutting structure 330 is provided on the bending part 320.

[0113] The present application also provides a method for preparing a laminated battery cell, which is used to prepare the laminated battery cell, comprising the following steps:

[0114] S10, providing a plurality of first pole pieces 100, a plurality of second pole pieces 200 and a diaphragm 300;

[0115] It can be understood that, for example, N first pole pieces 100 and M second pole pieces 200 are provided, and the first pole piece 100 and the second pole piece 200 are obtained by cutting the positive electrode material roll and the negative electrode material roll. During the preparation process, all the required first pole pieces 100 and the second pole pieces 200 can be cut, or they can be cut out before the first pole piece 100 or the second pole piece 200 is thermally composited during the thermal composite process;

[0116] S20, the first pole piece 100, the second pole piece 200 and the diaphragm 300 are thermally combined to form a composite laminate, such as Fig.15 As shown, the first pole piece 100 is thermally composited on one side of the diaphragm 300, the second pole piece 200 is thermally composited on the other side of the diaphragm 300, and the first pole piece 100 and the second pole piece 200 are alternately arranged along the length direction Y of the diaphragm 300; an incompletely cut structure 330 is processed on the composite laminate, and the incompletely cut structure 330 is arranged on the diaphragm 300 between the adjacent first pole piece 100 and the second pole piece 200;

[0117] Understandably, see Fig.15As shown, the diaphragm 300 is a single-layer diaphragm, and the first pole piece 100 and the second pole piece 200 are thermally composited on the diaphragm one by one. When the first pole piece 100 is a negative pole piece, the first first pole piece 100 is the first to be thermally composited on the diaphragm 300, and the Nth first pole piece 100 is the last to be composited on the diaphragm 300. All the first pole pieces 100 are on one side of the diaphragm 300, and all the second pole pieces 200 are on the other side of the diaphragm 300. In this embodiment, after the composite lamination process is completed, the incompletely cut structure 330 can be uniformly processed on the diaphragm 300, and the incompletely cut structure 330 can also be processed on the diaphragm 300 in time after the single first pole piece 100 or the single second pole piece 200 is processed.

[0118] S30, folding the composite laminate in a Z-shape along the straight line where the incompletely cut structure 330 is located to form a laminated battery cell, such as Fig.12 and Fig.14 The structure shown.

[0119] It can be understood that in this embodiment, the diaphragm 300, the first pole piece 100 and the second pole piece 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, so that the composite laminate is Z-folded along the straight line where the incompletely cut structure 330 is located, thereby improving the folding efficiency and folding quality and ensuring the alignment of the laminated battery cell 10.

[0120] 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.

[0121] 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.

[0122] The stacked battery cell provided in the embodiments of the present application is introduced in detail above. Specific examples are used herein 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 of the present application and its core idea. At the same time, for technical personnel 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 laminated battery cell, characterized in that: include: A plurality of first pole pieces (100), wherein the first pole pieces (100) are provided with first pole ears (110); a plurality of second pole pieces (200), each of the second pole pieces (200) being provided with a second pole lug (210), and the first pole piece (100) and the second pole piece (200) having opposite polarities; and A diaphragm (300), the diaphragm (300) comprising a plurality of main body portions (310) and a plurality of bending portions (320) arranged alternately and continuously; Among them, along the thickness direction of the first pole piece (100), the first pole piece (100) and the second pole piece (200) are alternately stacked, the adjacent first pole piece (100) and the second pole piece (200) are separated by the main body (310), the bending portion (320) is provided with an incompletely cut structure (330), the diaphragm (300) is folded at the incompletely cut structure (330), and the first pole ear (110) and the second pole ear (210) have at least a part of the structure located on the outside of the diaphragm (300).

2. The laminated 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).

3. The laminated battery cell according to claim 2, 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).

4. The laminated battery cell according to claim 2, characterized in that: The bent portion (320) of the first diaphragm (340) is fitted and connected to the bent portion (320) of the second diaphragm (350).

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

7. The laminated 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.

8. The laminated 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.

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

10. The laminated battery cell according to any one of claims 1 to 4, characterized in that: The first pole piece (100) and the second pole piece (200) have opposite polarities.

11. The laminated battery cell according to claim 10, characterized in that: The first pole piece (100) is a negative pole piece or a positive pole piece, and the second pole piece (200) is a positive pole piece or a negative pole piece.

12. The laminated battery cell according to claim 11, characterized in that: 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.

13. The laminated battery cell according to claim 12, characterized in that: The distance between the long side of the positive electrode sheet and the long side of the negative electrode sheet is S2, wherein 1 mm ≤ S2 ≤ 3 mm; And / or, the distance between the wide side of the positive electrode sheet and the wide side of the negative electrode sheet is S3, wherein 1mm≤S3≤3mm.

14. The laminated battery cell according to claim 12, characterized in that: The long side dimension of the main body (310) is greater than the long side dimension of the negative electrode sheet, and the wide side dimension of the main body (310) is greater than the wide side dimension of the negative electrode sheet.

15. The laminated battery cell according to claim 14, characterized in that: The distance between the long side of the negative electrode plate and the long side of the separator (300) is S4, wherein 2 mm ≤ S4 ≤ 4 mm; And / or, the diaphragm (300) includes a starting end (360), and the distance between the starting end (360) and the wide side of the negative electrode plate close to the starting end (360) is S5, wherein 1mm≤S5≤3mm.

16. The laminated battery cell according to any one of claims 1 to 4, characterized in that: The invention comprises N first pole pieces (100) and M second pole pieces (200), wherein N and M are both positive integers greater than 1, and when the first pole piece (100) is a negative pole piece and the second pole piece (200) is a positive pole piece, NM=1.

17. The laminated battery cell according to claim 16, characterized in that: The diaphragm (300) comprises a starting end (360) and an ending end (370); the first first pole piece (100) is closer to the starting end (360) of the diaphragm (300) than the first second pole piece (200); and the Nth first pole piece (100) is closer to the ending end (370) of the diaphragm (300) than the Mth second pole piece (200).

18. The laminated battery core according to any one of claims 1 to 4, characterized in that: It comprises N first pole pieces and M second pole pieces, where N and M are both positive integers greater than 1, and when the first pole piece (100) is a positive pole piece and the second pole piece (200) is a negative pole piece, MN=1.

19. The laminated battery core according to claim 18, characterized in that: The diaphragm (300) comprises a starting end (360) and an ending end (370); the first second pole piece (200) is closer to the starting end (360) of the diaphragm (300) than the first first pole piece (100); and the Mth second pole piece (200) is closer to the ending end (370) of the diaphragm (300) than the Nth first pole piece (100).

20. The laminated battery cell according to claim 1, characterized in that: Along the thickness direction of the first pole piece (100), the projections of all the first pole tabs (110) overlap, and / or the projections of all the second pole tabs (210) overlap.

21. The laminated battery core according to claim 1 or 20, characterized in that: Projections of the first pole tab (110) and the second pole tab (210) within the plane where the main body (310) is located are arranged side by side.

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