Composite structure of diaphragm, battery cell and battery

Abstract

The utility model provides a diaphragm composite structure, electric core and battery. The diaphragm composite structure of utility model embodiment includes first pole piece, first diaphragm and second diaphragm. First diaphragm is located at one side of first pole piece, and second diaphragm is located at the other side of first pole piece;First diaphragm has first winding start part, and first winding start part is connected with first pole piece;Second diaphragm has second winding start part, and second winding start part is connected with first pole piece. The diaphragm composite structure of utility model embodiment makes first winding start part and second winding start part be connected with first pole piece respectively, so that first diaphragm and second diaphragm are connected with first pole piece respectively, can avoid the problem of diaphragm folding and leaking out first pole piece in the winding core drawing process, and then can greatly improve the winding quality of electric core and the performance of electric core.

Description

Technical Field

[0001] This utility model relates to the field of battery cell technology, and in particular to a diaphragm composite structure, a battery cell, and a battery. Background Technology

[0002] A wound battery cell is typically made by winding a positive electrode, a negative electrode, and a separator.

[0003] In related technologies, the separator of the battery cell is located on both sides of the positive electrode or the negative electrode. During the winding and core pulling process, the separator is prone to folding and leaking out of the electrode, which greatly reduces the winding quality and performance of the battery cell.

[0004] Therefore, the diaphragm in the related technology is prone to folding and exposing the electrode sheet during the winding and core pulling process. Utility Model Content

[0005] This utility model provides a diaphragm composite structure, a battery cell, and a battery to solve the problem in related technologies where the diaphragm is prone to folding and exposing the electrode sheets during the winding and core-pulling process.

[0006] The diaphragm composite structure of this utility model embodiment includes:

[0007] First electrode plate,

[0008] A first diaphragm and a second diaphragm, wherein the first diaphragm is disposed on one side of the first electrode and the second diaphragm is disposed on the other side of the first electrode; the first diaphragm has a first winding start portion connected to the first electrode; the second diaphragm has a second winding start portion connected to the first electrode.

[0009] It is understood that the winding start portion of the first diaphragm is the starting portion where the first diaphragm begins to be wound, including the winding start end of the first diaphragm and the portion of the first diaphragm adjacent to its winding start end. Similarly, the winding start portion of the second diaphragm is the starting portion where the second diaphragm begins to be wound, including the winding start end of the second diaphragm and the portion of the second diaphragm adjacent to its winding start end.

[0010] At the same time, the connection between the first winding start part and the first electrode can be understood as the connection between the entire first winding start part and the first electrode, or the connection between a portion of the first winding start part and the first electrode. Similarly, the connection between the second winding start part and the first electrode can be understood as the connection between the entire second winding start part and the first electrode, or the connection between a portion of the second winding start part and the first electrode.

[0011] The diaphragm composite structure of this utility model connects the first winding start part and the second winding start part to the first electrode sheet respectively, so that the first diaphragm and the second diaphragm are respectively connected to the first electrode sheet. This can avoid the problem of the diaphragm folding and leaking out of the first electrode sheet during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell.

[0012] Therefore, the diaphragm composite structure of this utility model embodiment can avoid the problem of the diaphragm folding and exposing the first electrode during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell.

[0013] In some embodiments, the first diaphragm and the first electrode have a first overlapping region in the thickness direction of the first electrode, and a first composite region is provided in the first overlapping region to connect the first diaphragm and the first electrode; the second diaphragm and the first electrode have a second overlapping region in the thickness direction of the first electrode, and a second composite region is provided in the second overlapping region to connect the second diaphragm and the first electrode.

[0014] In some embodiments, the length A1 of the projection of the first composite region onto the width direction of the first diaphragm satisfies 0.5mm ≤ A1 ≤ the length of the paste-coated area of ​​the first electrode, and / or

[0015] The length B1 of the projection of the first composite region onto the length of the first diaphragm satisfies 5.0 mm ≤ B1 ≤ 200 mm, and / or

[0016] The length A2 of the projection of the second composite region onto the width direction of the second diaphragm satisfies 0.5mm ≤ A2 ≤ the length of the paste-coated area of ​​the first electrode, and / or

[0017] The length B2 of the projection of the second composite region onto the length of the second diaphragm satisfies 5.0 mm ≤ B2 ≤ 200 mm.

[0018] In some embodiments, in the width direction of the first diaphragm, the distance a1 between the edge of one side of the first composite region and the edge of one side of the first overlapping region satisfies 0 ≤ a1 ≤ 10 mm, and the distance a2 between the edge of the other side of the first composite region and the edge of the other side of the first overlapping region satisfies 0 ≤ a2 ≤ 10 mm; and / or

[0019] In the width direction of the second diaphragm, the distance a3 between the edge of one side of the second composite region and the edge of one side of the second overlapping region satisfies 0≤a3≤10mm, and the distance a4 between the edge of the other side of the second composite region and the edge of the other side of the second overlapping region satisfies 0≤a4≤10mm.

[0020] In some embodiments, a1 and a2 satisfy a1-a2=±(0-10)mm; a3 and a4 satisfy a3-a4=±(0-10)mm.

[0021] In some embodiments, along the length of the first diaphragm, the distance b1 between the edge of the first composite region adjacent to the winding start end of the first electrode and the winding start end of the first electrode satisfies 0 ≤ b1 ≤ 10 mm; along the length of the second diaphragm, the distance b2 between the edge of the second composite region adjacent to the winding start end of the first electrode and the winding start end of the first electrode satisfies 0 ≤ b2 ≤ 10 mm.

[0022] In some embodiments, the first composite region is provided with a plurality of first composite portions, and the first composite portions are connected to the first diaphragm and the first electrode sheet;

[0023] The length E1 of the projection of the first composite part in the width direction of the first diaphragm satisfies 0.5mm≤E1≤length of the coating area of ​​the first electrode, and the total length E2 of the projection of the plurality of the first composite parts in the width direction of the first diaphragm satisfies 0.00025≤E2 / A1≤1.

[0024] The length F1 of the projection of the first composite part onto the length of the first diaphragm satisfies 0.5mm ≤ F1 ≤ 200mm, and the total length F2 of the projections of the plurality of first composite parts onto the length of the first diaphragm satisfies 0.025 ≤ F2 / B1 ≤ 1; and / or

[0025] The second composite region is provided with a plurality of second composite parts, and the second composite parts are connected to the second diaphragm and the first electrode sheet;

[0026] The length E3 of the projection of the second composite part in the width direction of the second diaphragm satisfies 0.5mm≤E3≤length of the paste area of ​​the first electrode, and the total length E4 of the projection of the plurality of second composite parts in the width direction of the second diaphragm satisfies 0.00025≤E4 / A2≤1.

[0027] The length F3 of the projection of the second composite part onto the length direction of the second diaphragm satisfies 0.5mm≤F3≤200mm, and the total length F4 of the projections of the plurality of second composite parts onto the length direction of the second diaphragm satisfies 0.025≤F4 / B2≤1.

[0028] In some embodiments, at least a portion of the first composite portion may or may not overlap in the width direction of the first diaphragm; and / or,

[0029] At least a portion of the second composite portion may or may not overlap in the width direction of the second diaphragm.

[0030] In some embodiments, the peel strength of the first composite region and the second composite region is 0.01~20 N / cm.

[0031] This utility model also provides a battery cell.

[0032] The battery cell of this utility model embodiment has a wound structure. The battery cell includes the aforementioned diaphragm composite structure and a second electrode. One of the first electrode and the second electrode is a positive electrode, and the other electrode is a negative electrode.

[0033] The innermost ring of the first electrode includes a first corner segment, which is disposed opposite to the winding start end of the second electrode; the innermost ring of the second electrode includes a second corner segment, which is disposed opposite to the winding start end of the first electrode.

[0034] This utility model also provides a battery.

[0035] The battery of this utility model embodiment includes the battery cell described in the above embodiment. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is one of the structural schematic diagrams of the diaphragm composite structure according to an embodiment of the present utility model;

[0038] Figure 2 This is the second schematic diagram of the diaphragm composite structure according to an embodiment of the present invention;

[0039] Figure 3 This is a schematic diagram of the structure of the battery cell according to an embodiment of the present invention.

[0040] In the picture:

[0041] 100. Diaphragm composite structure; 200. Battery cell;

[0042] 1. First pole piece; 101. First corner segment;

[0043] 2. First diaphragm; 201. First overlapping region; 2011. First composite region; 20111. First composite part;

[0044] 3. Second diaphragm; 301. Second overlapping region; 3011. Second composite region; 30111. Second composite part;

[0045] 4. Second pole piece; 401. Second corner segment; Detailed Implementation

[0046] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0047] In the description of this utility model, it should be understood that the terms "longitudinal," "radial," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0048] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal encapsulation of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0049] In order to solve the problem that the diaphragms located on both sides of the electrode sheet in the related technology are prone to folding and leaking out of the electrode sheet during the winding and core pulling process.

[0050] This utility model provides a diaphragm composite structure 100.

[0051] The diaphragm composite structure 100 of this utility model embodiment includes a first electrode 1, a first diaphragm 2, and a second diaphragm 3.

[0052] The first diaphragm 2 is disposed on one side of the first electrode 1, and the second diaphragm 3 is disposed on the other side of the first electrode 1; the first diaphragm 2 has a first winding start portion, which is connected to the first electrode 1; the second diaphragm 3 has a second winding start portion, which is connected to the first electrode 1.

[0053] It is understood that the winding start portion of the first diaphragm 2 is the starting portion where the first diaphragm 2 begins to be wound, including the winding start end of the first diaphragm 2 and the portion of the first diaphragm 2 adjacent to its winding start end. Similarly, the winding start portion of the second diaphragm 3 is the starting portion where the second diaphragm 3 begins to be wound, including the winding start end of the second diaphragm 3 and the portion of the second diaphragm 3 adjacent to its winding start end.

[0054] At the same time, the connection between the first winding start part and the first electrode 1 can be understood as the connection between the entire first winding start part and the first electrode 1 or a partial connection between the first winding start part and the first electrode 1. Similarly, the connection between the second winding start part and the first electrode 1 can be understood as the connection between the entire second winding start part and the first electrode 1 or a partial connection between the second winding start part and the first electrode 1.

[0055] The diaphragm composite structure 100 of this utility model connects the first winding start portion and the second winding start portion to the first electrode 1 respectively, so that the first diaphragm 2 and the second diaphragm 3 are respectively connected to the first electrode 1. This can avoid the problem of the diaphragm folding and leaking out of the first electrode 1 during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell 200.

[0056] Therefore, the diaphragm composite structure 100 of this utility model embodiment can avoid the problem of the diaphragm folding and exposing the first electrode 1 during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell 200.

[0057] In some embodiments, the first diaphragm 2 and the first electrode 1 have a first overlapping region 201 in the thickness direction of the first electrode 1, and a first composite region 2011 is provided in the first overlapping region 201 to connect the first diaphragm 2 and the first electrode 1; the second diaphragm 3 and the first electrode 1 have a second overlapping region 301 in the thickness direction of the first electrode 1, and a second composite region 3011 is provided in the second overlapping region 301 to connect the second diaphragm 3 and the first electrode 1.

[0058] It is understandable that the first composite region 2011 refers to the region connecting the first diaphragm 2 to the first electrode 1, and the second composite region 3011 is the region connecting the second diaphragm 3 to the first electrode 1.

[0059] The first overlapping region 201 and the first composite region 2011 are set to connect the first diaphragm 2 and the first electrode 1, and the second overlapping region 301 and the second composite region 3011 are set to connect the second diaphragm 3 and the first electrode 1. This prevents the winding needle from moving the diaphragm during the winding and core pulling process, thereby avoiding the problem of the first diaphragm 2 and the second diaphragm 3 flipping the first electrode 1. This can greatly improve the winding quality and performance of the cell 200.

[0060] In some embodiments, the length A1 of the projection of the first composite region 2011 in the width direction of the first diaphragm 2 satisfies 0.5mm ≤ A1 ≤ the length of the paste-coated area of ​​the first electrode 1.

[0061] It is understandable that the length of the paste-coated area of ​​the first electrode 1 refers to the length of the active material coating on the first electrode.

[0062] The larger the length A1 of the projection of the first composite region 2011 in the width direction of the first diaphragm 2, the greater the composite strength of the first composite region 2011 and the greater the composite cost of the first composite region 2011.

[0063] The smaller the length A1 of the projection of the first composite region 2011 in the width direction of the first diaphragm 2, the greater the composite strength of the first composite region 2011 and the lower the composite cost of the first composite region 2011.

[0064] Therefore, by setting the length A1 of the projection of the first composite region 2011 onto the width direction of the first diaphragm 2 to the range described above, the composite cost of the first composite region 2011 can be reduced while meeting the composite requirements of the first diaphragm 2 and the first electrode 1.

[0065] In some embodiments, the length B1 of the projection of the first composite region 2011 in the length direction of the first diaphragm 2 satisfies 5.0 mm ≤ B1 ≤ 200 mm.

[0066] Preferably, the length B1 of the projection of the first composite region 2011 in the length direction of the first diaphragm 2 is 5 mm, 10 mm, 25 mm, 50 mm, 75 mm, 100 mm, 150 mm, or 200 mm.

[0067] The larger the length B1 of the projection of the first composite region 2011 in the length direction of the first diaphragm 2, the greater the composite strength of the first composite region 2011 and the greater the composite cost of the first composite region 2011.

[0068] The smaller the length B1 of the projection of the first composite region 2011 in the length direction of the first diaphragm 2, the greater the composite strength of the first composite region 2011 and the lower the composite cost of the first composite region 2011.

[0069] Therefore, by setting the length B1 of the projection of the first composite region 2011 in the length direction of the first diaphragm 2 to the above range, the composite cost of the first composite region 2011 can be reduced while meeting the composite requirements of the first diaphragm 2 and the first electrode 1.

[0070] In some embodiments, the length A2 of the projection of the second composite region 3011 in the width direction of the second diaphragm 3 satisfies 0.5mm ≤ A2 ≤ the length of the paste-coated area of ​​the first electrode.

[0071] It is understandable that the length of the paste-coated area of ​​the first electrode 1 refers to the length of the active material coating on the first electrode.

[0072] The larger the length A2 of the projection of the second composite region 3011 in the width direction of the second diaphragm 3, the greater the composite strength of the first composite region 2011, and the greater the composite cost of the first composite region 2011.

[0073] The smaller the length A2 of the projection of the second composite region 3011 in the width direction of the second diaphragm 3, the greater the composite strength of the first composite region 2011 and the lower the composite cost of the first composite region 2011.

[0074] Therefore, by setting the length A2 of the projection of the second composite region 3011 onto the width direction of the second diaphragm 3 to the range described above, the composite cost of the first composite region 2011 can be reduced while meeting the composite requirements of the first diaphragm 2 and the first electrode 1.

[0075] In some embodiments, the length B2 of the projection of the second composite region 3011 in the length direction of the second diaphragm 3 satisfies 5.0 mm ≤ B2 ≤ 200 mm.

[0076] Preferably, the length B2 of the projection of the second composite region 3011 in the length direction of the second diaphragm 3 is 5 mm, 10 mm, 25 mm, 50 mm, 75 mm, 100 mm, 150 mm, or 200 mm.

[0077] The larger the length B2 of the projection of the second composite region 3011 in the length direction of the second diaphragm 3, the greater the composite strength of the first composite region 2011 and the greater the composite cost of the first composite region 2011.

[0078] The smaller the length B2 of the projection of the second composite region 3011 in the length direction of the second diaphragm 3, the greater the composite strength of the first composite region 2011 and the lower the composite cost of the first composite region 2011.

[0079] Therefore, by setting the length B2 of the projection of the second composite region 3011 in the length direction of the second diaphragm 3 to the above range, the composite cost of the first composite region 2011 can be reduced while meeting the composite requirements of the first diaphragm 2 and the first electrode 1.

[0080] In some embodiments, in the width direction of the first diaphragm 2, the distance a1 between the edge of one side of the first composite region 2011 and the edge of one side of the first overlapping region 201 satisfies 0≤a1≤10mm; the distance a2 between the edge of the other side of the first composite region 2011 and the edge of the other side of the first overlapping region 201 satisfies 0≤a2≤10mm.

[0081] Preferably, the distance a1 between the edge of one side of the first composite region 2011 and the edge of one side of the first overlapping region 201 is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0082] Preferably, the distance a2 between the edge of the first composite region 2011 on the other side and the edge of the first overlapping region 201 on the other side is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0083] By setting the distance a1 between the edge of one side of the first composite region 2011 and the edge of one side of the first overlapping region 201 and the distance a2 between the edge of the other side of the first composite region 2011 and the edge of the other side of the first overlapping region 201 to the above range, the composite requirements of the first diaphragm 2 and the first electrode 1 can be met.

[0084] In some embodiments, in the width direction of the second diaphragm 3, the distance a3 between the edge of one side of the second composite region 3011 and the edge of one side of the second overlapping region 301 satisfies 0≤a3≤10mm; the distance a4 between the edge of the other side of the second composite region 3011 and the edge of the other side of the second overlapping region 301 satisfies 0≤a4≤10mm.

[0085] Preferably, the distance a3 between the edge of the second composite region 3011 and the edge of the second overlapping region 301 is 0.1 mm, 0.5 mm, 2.5 mm, 5 mm, or 10 mm.

[0086] Preferably, the distance a4 between the edge of the second composite region 3011 on the other side and the edge of the second overlapping region 301 on the other side is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0087] By setting the distance a3 between the edge of one side of the second composite region 3011 and the edge of one side of the second overlapping region 301 and the distance a4 between the edge of the other side of the second composite region 3011 and the edge of the other side of the second overlapping region 301 to the above range, the composite requirements of the second diaphragm 3 and the first electrode 1 can be met.

[0088] In some embodiments, a1 and a2 satisfy a1-a2=±(0-10)mm; a3 and a4 satisfy a3-a4=±(0-10)mm.

[0089] It is understandable that when a1-a2=0, the first composite region 2011 is centrally located on the first overlapping region 201 in the width direction of the first diaphragm 2, and when a3-a4=0, the second composite region 3011 is centrally located on the second overlapping region 301 in the width direction of the second diaphragm 3.

[0090] At the same time, a1 and a2 satisfy a1-a2=±(0-10)mm; a3 and a4 satisfy a3-a4=±(0-10)mm, which can improve the processing tolerance of the first composite region 2011 and the second composite region 3011 and reduce the processing difficulty.

[0091] In some embodiments, in the length direction of the first diaphragm 2, the distance b1 between the edge of the first composite region 2011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 satisfies 0≤b1≤10mm; in the length direction of the second diaphragm 3, the distance b2 between the edge of the second composite region 3011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 satisfies 0≤b2≤10mm.

[0092] Preferably, in the length direction of the first diaphragm 2, the distance b1 between the edge of the first composite region 2011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 is 0.1 mm, 0.5 mm, 2.5 mm, 5 mm, or 10 mm.

[0093] Preferably, in the length direction of the second diaphragm 3, the distance b2 between the edge of the second composite region 3011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 is 0.1 mm, 0.5 mm, 2.5 mm, 5 mm, or 10 mm.

[0094] By setting the distance b1 between the edge of the first composite region 2011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 and the distance b2 between the edge of the second composite region 3011 adjacent to the winding start end of the first electrode 1 and the winding start end of the first electrode 1 to the above range, the composite requirements of the first diaphragm 2 and the first electrode 1 as well as the composite requirements of the second diaphragm 3 and the first electrode 1 can be met.

[0095] In some embodiments, a plurality of first composite parts 20111 are provided in the first composite region 2011, and the first composite parts 20111 are connected to the first diaphragm 2 and the first electrode 1;

[0096] The length E1 of the projection of the first composite part 20111 onto the width direction of the first diaphragm 2 satisfies 0.5mm≤E1≤length of the coating area of ​​the first electrode 1, and the total length E2 of the projection of the plurality of first composite parts 20111 onto the width direction of the first diaphragm 2 satisfies 0.00025≤E2 / A1≤1.

[0097] It is understandable that the total length E2 of the projections of the multiple first composite parts 20111 in the width direction of the first diaphragm 2 can be divided into two cases.

[0098] Firstly, the projections of the multiple first composite parts 20111 in the width direction of the first diaphragm 2 do not overlap with each other. The total length E2 of the projections of the multiple first composite parts 20111 in the width direction of the first diaphragm 2 can be understood as the sum of the lengths E1 of the projections of the multiple first composite parts 20111 in the width direction of the first diaphragm 2.

[0099] Secondly, the projections of multiple first composite parts 20111 onto the width direction of the first diaphragm 2 overlap. The total length E2 of the projections of multiple first composite parts 20111 onto the width direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple first composite parts 20111 onto the width direction of the first diaphragm 2. For example, if the projections of two first composite parts 20111 onto the width direction of the first diaphragm 2 overlap, then the total length E2 of the projections of the two first composite parts 20111 onto the width direction of the first diaphragm 2 is equal to the sum of the lengths of the overlapping portion and the remaining portion of the two first composite parts 20111 onto the width direction of the projections of the two first composite parts 20111 onto the width direction of the first diaphragm 2.

[0100] The length F1 of the projection of the first composite part 20111 in the length direction of the first diaphragm 2 satisfies 0.5mm≤F1≤200mm, and the total length F2 of the projection of the multiple first composite parts 20111 in the length direction of the first diaphragm 2 satisfies 0.025≤F2 / B1≤1.

[0101] It is understandable that the total length F2 of the projections of the multiple first composite parts 20111 along the length direction of the first diaphragm 2 can be divided into two cases.

[0102] Firstly, the projections of the multiple first composite parts 20111 in the length direction of the first diaphragm 2 do not overlap with each other. The total length F2 of the projections of the multiple first composite parts 20111 in the length direction of the first diaphragm 2 can be understood as the sum of the lengths F1 of the projections of the multiple first composite parts 20111 in the length direction of the first diaphragm 2.

[0103] Secondly, the projections of multiple first composite parts 20111 in the length direction of the first diaphragm 2 overlap. The total length F2 of the projections of multiple first composite parts 20111 in the length direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple first composite parts 20111 in the length direction of the first diaphragm 2. For example, if the projections of two first composite parts 20111 in the length direction of the first diaphragm 2 overlap, then the total length F2 of the projections of the two first composite parts 20111 in the length direction of the first diaphragm 2 is equal to the sum of the length of the overlapping portion and the length of the projection of the remaining portion of the two first composite parts 20111 in the overlapping portion in the length direction of the first diaphragm 2.

[0104] The second composite region 3011 is provided with a plurality of second composite parts 30111, and the second composite parts 30111 are connected to the second diaphragm 3 and the first electrode 1;

[0105] The length E3 of the projection of the second composite part 30111 onto the width direction of the second diaphragm 3 satisfies 0.5mm≤E3≤length of the coating area of ​​the first electrode (1), and the total length E4 of the projection of the multiple second composite parts 30111 onto the width direction of the second diaphragm 3 satisfies 0.00025≤E4 / A2≤1.

[0106] It is understandable that the total length E4 of the projections of the multiple second composite parts 30111 in the width direction of the first diaphragm 2 can be divided into two cases.

[0107] Firstly, the projections of the multiple second composite parts 30111 in the width direction of the first diaphragm 2 do not overlap with each other. The total length E4 of the projections of the multiple second composite parts 30111 in the width direction of the first diaphragm 2 can be understood as the sum of the lengths E3 of the projections of the multiple second composite parts 30111 in the width direction of the first diaphragm 2.

[0108] Secondly, the projections of multiple second composite parts 30111 onto the width direction of the first diaphragm 2 overlap. The total length E4 of the projections of multiple second composite parts 30111 onto the width direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple second composite parts 30111 onto the width direction of the first diaphragm 2. For example, if the projections of two second composite parts 30111 onto the width direction of the first diaphragm 2 overlap, then the total length E4 of the projections of the two second composite parts 30111 onto the width direction of the first diaphragm 2 is equal to the sum of the lengths of the overlapping portion and the remaining portion of the two second composite parts 30111 onto the width direction of the first diaphragm 2.

[0109] The length F3 of the projection of the second composite part 30111 in the length direction of the second diaphragm 3 satisfies 0.5mm≤F3≤200mm, and the total length F4 of the projection of the multiple second composite parts 30111 in the length direction of the second diaphragm 3 satisfies 0.025≤F4 / B2≤1.

[0110] It is understandable that the total length F4 of the projections of the multiple second composite parts 30111 onto the length direction of the first diaphragm 2 can be divided into two cases.

[0111] Firstly, the projections of the multiple second composite parts 30111 in the length direction of the first diaphragm 2 do not overlap with each other. The total length F4 of the projections of the multiple second composite parts 30111 in the length direction of the first diaphragm 2 can be understood as the sum of the lengths F3 of the projections of the multiple second composite parts 30111 in the length direction of the first diaphragm 2.

[0112] Secondly, the projections of multiple second composite parts 30111 in the length direction of the first diaphragm 2 overlap. The total length F4 of the projections of multiple second composite parts 30111 in the length direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple second composite parts 30111 in the length direction of the first diaphragm 2. For example, if the projections of two second composite parts 30111 in the length direction of the first diaphragm 2 overlap, then the total length F4 of the projections of the two second composite parts 30111 in the length direction of the first diaphragm 2 is equal to the sum of the length of the overlapping portion and the length of the projection of the remaining portion of the two second composite parts 30111 in the overlapping portion in the length direction of the first diaphragm 2.

[0113] By setting the above parameters (including: the length E1 of the projection of the first composite part 20111 in the width direction of the first diaphragm 2, the total length E2 of the projection of the multiple first composite parts 20111 in the width direction of the first diaphragm 2, the length F1 of the projection of the first composite part 20111 in the length direction of the first diaphragm 2, the total length F2 of the projection of the multiple first composite parts 20111 in the length direction of the first diaphragm 2, the length E3 of the projection of the second composite part 30111 in the width direction of the second diaphragm 3, the total length E4 of the projection of the multiple second composite parts 30111 in the width direction of the second diaphragm 3, the length F3 of the projection of the second composite part 30111 in the length direction of the second diaphragm 3, and the total length F4 of the projection of the multiple second composite parts 30111 in the length direction of the second diaphragm 3) to the above range, the composite cost can be reduced while meeting the composite requirements of the first composite part 20111 and the second composite part 30111.

[0114] In some embodiments, the peel strength of the first composite region 2011 is 0.01~20 N / cm; the peel strength of the second composite region 3011 is 0.01~20 N / cm.

[0115] Furthermore, the peel strength test standard used to test the peel strength of the first composite region 2011 is ASTM D903 or GB / T 279. Specifically, the first diaphragm 2 and the first electrode 1 are composited through the first composite region 2011 and peeled at a specific angle (90° or 180°) and a specific speed. The force value change required during the peeling process is recorded using a force value sensor, and then the peel strength per unit width of the first composite region 2011 is calculated.

[0116] It is understandable that the greater the peel strength of the first composite region 2011, the higher the required composite cost, and vice versa.

[0117] The electrode assembly of this utility model reduces the composite cost of the first composite region 2011 by setting the peel strength of the first composite region 2011 to 0.01~5.0 N / cm, while meeting the composite requirements of the first diaphragm 2 and the first electrode 1.

[0118] Similarly, further, the peel strength test standard used to test the peel strength of the second composite region 3011 is ASTM D903 or GB / T 279. Specifically, the second diaphragm 3 and the first electrode 1 are composited through the second composite region 3011 and peeled at a specific angle (90° or 180°) and a specific speed. The force value change required during the peeling process is recorded using a force value sensor, and then the peel strength per unit width of the second composite region 3011 is calculated.

[0119] It is understandable that the greater the peel strength of the second composite region 3011, the higher the required composite cost, and vice versa.

[0120] The electrode assembly of this utility model reduces the composite cost of the second composite region 3011 by setting the peel strength of the second composite region 3011 to 0.01~5.0 N / cm, while meeting the composite requirements of the second diaphragm 3 and the first electrode 1.

[0121] This utility model also provides a battery cell 200, which is a wound structure and includes the diaphragm composite structure 100 and the second electrode 4 described in the above embodiments.

[0122] One of the first electrode 1 and the second electrode 4 is a positive electrode, and the other electrode is a negative electrode;

[0123] The innermost ring of the first electrode 101 includes a first corner segment 1011, which is positioned opposite to the winding start end of the second electrode 102; the innermost ring of the second electrode 102 includes a second corner segment 1021, which is positioned opposite to the winding start end of the first electrode 101.

[0124] It is understandable that when the above-mentioned wound cell 200 is wound and pulled, the diaphragms on both sides of the first electrode 1 of the cell 200 in the related technology are prone to folding and leaking out of the first electrode 1, which will greatly reduce the winding quality and performance of the cell 200.

[0125] Therefore, by setting the diaphragm composite structure 100 described in the above embodiment, the battery cell 200 of this utility model connects the first winding start part and the second winding start part to the first electrode 1 respectively, so that the first diaphragm 2 and the second diaphragm 3 are connected to the first electrode 1 respectively. This can avoid the problem of the diaphragm folding and leaking out of the first electrode 1 during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell 200.

[0126] This utility model also provides a battery.

[0127] The battery of this utility model embodiment includes the battery cell described in the above embodiment.

[0128] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A diaphragm composite structure, characterized in that, include: First electrode (1). A first diaphragm (2) and a second diaphragm (3), wherein the first diaphragm (2) is disposed on one side of the first electrode (1) and the second diaphragm (3) is disposed on the other side of the first electrode (1); the first diaphragm (2) has a first winding start portion, which is connected to the first electrode (1); the second diaphragm (3) has a second winding start portion, which is connected to the first electrode (1).

2. The diaphragm composite structure according to claim 1, characterized in that, The first diaphragm (2) and the first electrode (1) have a first overlapping region (201) in the thickness direction of the first electrode (1), and a first composite region (2011) is provided in the first overlapping region (201) to connect the first diaphragm (2) and the first electrode (1); the second diaphragm (3) and the first electrode (1) have a second overlapping region (301) in the thickness direction of the first electrode (1), and a second composite region (3011) is provided in the second overlapping region (301) to connect the second diaphragm (3) and the first electrode (1).

3. The diaphragm composite structure according to claim 2, characterized in that, The length A1 of the projection of the first composite region (2011) onto the width direction of the first diaphragm (2) satisfies 0.5mm ≤ A1 ≤ the length of the paste-coated area of ​​the first electrode (1), and / or The length B1 of the projection of the first composite region (2011) onto the length direction of the first diaphragm (2) satisfies 5.0 mm ≤ B1 ≤ 200 mm, and / or The length A2 of the projection of the second composite region (3011) onto the width direction of the second diaphragm (3) satisfies 0.5mm ≤ A2 ≤ the length of the paste-coated area of ​​the first electrode (1), and / or The length B2 of the projection of the second composite region (3011) onto the length of the second diaphragm (3) satisfies 5.0mm≤B2≤200mm.

4. The diaphragm composite structure according to claim 2, characterized in that, In the width direction of the first diaphragm (2), the distance a1 between one edge of the first composite region (2011) and one edge of the first overlapping region (201) satisfies 0 ≤ a1 ≤ 10 mm, and the distance a2 between the other edge of the first composite region (2011) and the other edge of the first overlapping region (201) satisfies 0 ≤ a2 ≤ 10 mm; and / or In the width direction of the second diaphragm (3), the distance a3 between the edge of one side of the second composite region (3011) and the edge of one side of the second overlapping region (301) satisfies 0≤a3≤10mm, and the distance a4 between the edge of the other side of the second composite region (3011) and the edge of the other side of the second overlapping region (301) satisfies 0≤a4≤10mm.

5. The diaphragm composite structure according to claim 4, characterized in that, a1 and a2 satisfy a1-a2=±(0-10)mm; a3 and a4 satisfy a3-a4=±(0-10)mm.

6. The diaphragm composite structure according to claim 2, characterized in that, In the length direction of the first diaphragm (2), the distance b1 between the edge of the first composite region (2011) adjacent to the winding start end of the first electrode (1) and the winding start end of the first electrode (1) satisfies 0≤b1≤10mm; in the length direction of the second diaphragm (3), the distance b2 between the edge of the second composite region (3011) adjacent to the winding start end of the first electrode (1) and the winding start end of the first electrode (1) satisfies 0≤b2≤10mm.

7. The diaphragm composite structure according to any one of claims 2-6, characterized in that, The first composite region (2011) is provided with a plurality of first composite parts (20111), and the first composite parts (20111) are connected to the first diaphragm (2) and the first electrode (1). The length E1 of the projection of the first composite part (20111) in the width direction of the first diaphragm (2) satisfies 0.5mm≤E1≤length of the paste area of ​​the first electrode (1), and the total length E2 of the projection of the plurality of the first composite parts (20111) in the width direction of the first diaphragm (2) satisfies 0.00025≤E2 / A1≤1; The length F1 of the projection of the first composite part (20111) onto the length direction of the first diaphragm (2) satisfies 0.5mm≤F1≤200mm, and the total length F2 of the projections of the plurality of the first composite parts (20111) onto the length direction of the first diaphragm (2) satisfies 0.025≤F2 / B1≤1; and / or The second composite region (3011) is provided with a plurality of second composite parts (30111), and the second composite parts (30111) are connected to the second diaphragm (3) and the first electrode (1). The length E3 of the projection of the second composite part (30111) onto the width direction of the second diaphragm (3) satisfies 0.5mm≤E3≤length of the paste area of ​​the first electrode (1), and the total length E4 of the projection of the plurality of second composite parts (30111) onto the width direction of the second diaphragm (3) satisfies 0.00025≤E4 / A2≤1; The length F3 of the projection of the second composite part (30111) onto the length direction of the second diaphragm (3) satisfies 0.5mm≤F3≤200mm, and the total length F4 of the projection of the plurality of second composite parts (30111) onto the length direction of the second diaphragm (3) satisfies 0.025≤F4 / B2≤1.

8. The diaphragm composite structure according to claim 7, characterized in that, At least a portion of the first composite portion may or may not overlap in the width direction of the first diaphragm; and / or, At least a portion of the second composite portion may or may not overlap in the width direction of the second diaphragm.

9. The diaphragm composite structure according to claim 2, characterized in that, The peel strength of the first composite region (2011) and the second composite region (3011) is 0.01~20 N / cm.

10. A battery cell, characterized in that, The battery cell (200) has a wound structure and includes a diaphragm composite structure (100) as described in any one of claims 1-9 and a second electrode (4), wherein one of the first electrode (1) and the second electrode (4) is a positive electrode and the other is a negative electrode. The innermost ring of the first electrode (1) includes a first corner segment (1011), which is disposed opposite to the winding start end of the second electrode (4); the innermost ring of the second electrode (4) includes a second corner segment (1021), which is disposed opposite to the winding start end of the first electrode (1).

11. A battery, characterized in that, Includes the battery cell (200) as described in claim 10.

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