Electrode assembly, wound cell, and battery

Abstract

The utility model provides a kind of electrode assembly, winding cell and battery, the electrode assembly of utility model embodiment includes pole piece, first diaphragm and second diaphragm, first pole piece has first winding beginning end;First diaphragm is located in one side of first pole piece, and second diaphragm is located in the other side of first pole piece;In the length direction of first pole piece, first diaphragm has first area beyond first winding beginning end, and second diaphragm has second area beyond first winding beginning end;First area is connected with second area.The electrode assembly of utility model embodiment is connected by first area and second area, can avoid that winding needle drives diaphragm to move in winding core drawing process, and then can avoid the problem that diaphragm is folded, even leaks out pole piece, so it can greatly improve the winding quality of cell and the performance of cell.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to an electrode assembly, a wound 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 is placed 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 cell. Utility Model Content

[0004] This utility model provides an electrode assembly to solve the problem in related technologies where the diaphragms located on both sides of the electrode are prone to folding.

[0005] The electrode assembly of this utility model embodiment includes: A first electrode, the first electrode having a first winding start end; 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; Along the length of the first electrode, the first diaphragm has a first region extending beyond the first winding start, and the second diaphragm has a second region extending beyond the first winding start; the first region and the second region are connected.

[0006] The electrode assembly of this utility model connects the first region of the first diaphragm extending from the first winding start end to the second region of the second diaphragm extending from the first winding start end. This avoids the winding needle from driving the diaphragm to move during the winding and core pulling process, thereby avoiding problems such as diaphragm folding or even leakage of electrode sheets. This can greatly improve the winding quality and performance of the battery cell.

[0007] Therefore, the electrode assembly of this utility model embodiment can avoid the problem of diaphragm folding or even electrode leakage during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell.

[0008] In some embodiments, in the length direction of the electrode, the first region and the second region have an overlapping region in the thickness direction of the electrode, and a composite region is provided in the overlapping region to connect the first diaphragm and the second diaphragm.

[0009] In some embodiments, the length A of the projected overlapping region in the width direction of the first diaphragm satisfies 1.0 mm ≤ A ≤ 10 mm, and / or The projected length B of the overlapping region along the length direction of the first diaphragm satisfies 5.0 mm ≤ B ≤ 300 mm.

[0010] In some embodiments, the length C of the composite region projected onto the width direction of the first diaphragm satisfies 0.5 mm ≤ C ≤ A, and / or The length D of the composite region projected onto the length of the first diaphragm satisfies 5% ≤ D / B ≤ 100%.

[0011] In some embodiments, in the width direction of the first diaphragm, the distance a1 between the edge of the composite region on one side and the edge of the overlapping region on one side satisfies 0.1mm≤a1≤10mm; The distance a2 between the edge of the composite region on the other side and the edge of the overlapping region on the other side satisfies 0.1mm≤a2≤10mm.

[0012] In some embodiments, a1 and a2 satisfy a1-a2=±(0-9.9)mm.

[0013] In some embodiments, in the longitudinal direction of the first diaphragm, the distance b1 between the edge of the composite region adjacent to the first winding start and the edge of the overlapping region adjacent to the first winding start satisfies 0 ≤ b1 ≤ 10 mm. The distance b2 between the edge of the composite region away from the first winding start and the edge of the overlapping region away from the first winding start satisfies 0 ≤ b2 ≤ 10 mm.

[0014] In some embodiments, b1 and b2 satisfy b1-b2=±(0-10)mm.

[0015] In some embodiments, the composite region is provided with a plurality of composite portions, the composite portions connecting the first diaphragm and the second diaphragm. The projections of the multiple composite parts onto the width direction of the first diaphragm do not overlap with each other, and the length E of the projection of the composite part onto the width direction of the first diaphragm satisfies 0.5mm≤E≤10mm, and the sum E of the lengths E of the projections of the multiple composite parts onto the width direction of the first diaphragm satisfies 0.05≤Etotal / A≤1. The projections of the multiple composite parts onto the length direction of the first diaphragm do not overlap with each other. The length F of the projection of the composite part onto the length direction of the first diaphragm satisfies 0.5mm≤F≤100mm, and the sum F of the lengths F of the projections of the multiple composite parts onto the length direction of the first diaphragm satisfies 0.05≤Ftotal / B≤1.

[0016] In some embodiments, the peel strength of the composite region is 0.01~5.0 N / cm.

[0017] This utility model also provides a wound battery cell.

[0018] The wound battery cell of this utility model, as described in the embodiments, includes an electrode assembly as described in the above embodiments, and a second electrode, wherein one of the first electrode and the second electrode is a positive electrode and the other electrode is a negative electrode. The innermost ring of the first electrode includes a first corner segment, which is disposed opposite to the second 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 first winding start end of the first electrode.

[0019] This utility model also provides a battery.

[0020] The battery of this utility model embodiment includes the wound cell described in the above embodiment. Attached Figure Description

[0021] 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.

[0022] Figure 1 This is a schematic diagram of the electrode assembly according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the wound battery cell according to an embodiment of the present invention.

[0023] In the picture: 1. First pole piece; 101. First winding start; 102. First corner segment; 2. First diaphragm; 201. First region; 3. Second diaphragm; 301. Second region; 4. Overlapping areas; 5. Composite area; 501. Composite section; 6. Second pole piece; 601. Second winding start end; 602. Second corner segment. Detailed Implementation

[0024] 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.

[0025] 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.

[0026] 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.

[0027] In order to solve the problem that the diaphragms located on both sides of the electrode in the related technology are prone to folding during the winding and core pulling process.

[0028] This invention provides an electrode assembly.

[0029] The electrode assembly of this utility model embodiment includes a first electrode 1, a first diaphragm 2, and a second diaphragm 3. 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 electrode 1 has a first winding start end 101. In the length direction of the first electrode 1, the portion of the first diaphragm 2 extending out of the first winding start end 101 is connected to the portion of the second diaphragm 3 extending out of the first winding start end 101.

[0030] The electrode assembly of this utility model connects the portion of the first diaphragm 2 extending from the first winding start 101 with the portion of the second diaphragm 3 extending from the first winding start 101. This avoids the diaphragm from moving during the winding and core pulling process, thereby preventing the diaphragm from folding or even the first electrode 1 from leaking out. This greatly improves the winding quality and performance of the battery cell.

[0031] Therefore, the electrode assembly of this utility model embodiment can avoid the problem of diaphragm folding or even leakage of the first electrode 1 during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell.

[0032] The following is in conjunction with the appendix Figure 1 The electrode assembly of an embodiment of the present invention is described.

[0033] The electrode assembly of this utility model embodiment includes a first electrode 1, a first diaphragm 2, and a second diaphragm 3.

[0034] like Figure 1 As shown, the first diaphragm 2 is disposed on one side of the first electrode 1 in the thickness direction, and the second diaphragm 3 is disposed on the other side of the first electrode 1 in the thickness direction.

[0035] Optionally, the first electrode 1 can be either a positive electrode or a negative electrode, depending on the core structure.

[0036] like Figure 1 As shown, the first electrode 1 has a first winding start end 101. In the length direction of the first electrode 1, the portion of the first diaphragm 2 extending out of the first winding start end 101 is connected to the portion of the second diaphragm 3 extending out of the first winding start end 101.

[0037] It is understandable that the portion of the first diaphragm 2 extending out of the first winding start 101 of the first electrode 1 has the first winding start 101 of the first diaphragm 2, and the portion of the second diaphragm 3 extending out of the first winding start 101 of the first electrode 1 has the first winding start 101 of the second diaphragm 3. In other words, connecting the portion of the first diaphragm 2 extending out of the first winding start 101 with the portion of the second diaphragm 3 extending out of the first winding start 101 essentially means connecting the first winding start 101 of the first diaphragm 2 and the second diaphragm 3 to form a connected whole. This prevents the winding needle from moving the diaphragm during the winding and core pulling process, thereby avoiding the problems of the first diaphragm 2 and the second diaphragm 3 folding over or even leaking out of the first electrode 1, thus greatly improving the winding quality and performance of the battery cell.

[0038] In some embodiments, in the length direction of the first electrode 1, the first diaphragm 2 has a first region 201 extending beyond the first winding start 101, and the second diaphragm 3 has a second region 301 extending beyond the first winding start 101; the first region 201 and the second region 301 have an overlapping region 4 in the thickness direction of the first electrode 1, and a composite region 5 is provided in the overlapping region 4 to connect the first diaphragm 2 and the second diaphragm 3.

[0039] It is understandable that the composite region 5 refers to the region that connects the first diaphragm 2 and the second diaphragm 3.

[0040] By setting a composite region 5 on the overlapping region 4 of the first region 201 and the second region 301, the first region 201 of the first diaphragm 2 and the second region 301 of the second diaphragm 3 can be connected. 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 folding or even the first electrode 1 being exposed. This can greatly improve the winding quality of the battery cell.

[0041] In some embodiments, the length A of the projection of the overlapping region 4 onto the width direction of the first diaphragm 2 satisfies 1.0 mm ≤ A ≤ 10 mm, and / or The projected length B of the overlapping region 4 in the length direction of the first diaphragm 2 satisfies 5.0mm≤B≤300mm.

[0042] Preferably, the length A of the overlapping region 4 projected in the width direction of the first diaphragm 2 is 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm.

[0043] Preferably, the projected length B of the overlapping region 4 in the length direction of the first diaphragm 2 is 5 mm, 10 mm, 25 mm, 50 mm, 75 mm, 100 mm, 150 mm, 200 mm, 250 mm or 300 mm.

[0044] By setting the length A of the overlapping region 4 projected in the width direction of the first diaphragm 2 and the length B of the overlapping region 4 projected in the length direction of the first diaphragm 2 to the above range, it is possible to meet the needs of setting the composite region 5 in the future while avoiding the area of ​​the overlapping region 4 being too large, which would increase the cell volume and reduce the energy density of the cell.

[0045] In some embodiments, the length C of the composite region 5 projected in the width direction of the first diaphragm 2 satisfies 0.5 mm ≤ C ≤ A, and / or The length D of the composite region 5 projected along the length direction of the first diaphragm 2 satisfies 5%≤D / B≤100%.

[0046] It is understandable that the larger the length C projected onto the width direction of the composite region 5 and the length D projected onto the length direction of the first diaphragm 2, the higher the required composite cost. Conversely, the smaller the length C projected onto the width direction of the composite region and the length D projected onto the length direction of the first diaphragm 2, the lower the required composite cost.

[0047] The electrode assembly of this utility model reduces the composite cost of the composite region 5 by setting the length C projected onto the width direction of the composite region and the length D projected onto the length direction of the first diaphragm 2 within the aforementioned range, while ensuring that the composite requirements of the first diaphragm 2 and the second diaphragm 3 are met. In some embodiments, in the width direction of the first diaphragm 2, the distance a1 between the edge of one side of the composite region 5 and the edge of one side of the overlapping region 4 satisfies 0.1mm≤a1≤10mm; Preferably, the distance a1 between the edge of the composite region 5 and the edge of the overlapping region 4 is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0048] The distance a2 between the edge of the other side of the composite region 5 and the edge of the other side of the overlapping region 4 satisfies 0.1mm≤a2≤10mm.

[0049] Preferably, the distance a2 between the edge of the other side of the composite region 5 and the edge of the other side of the overlapping region 4 is 0.1 mm, 0.5 mm, 2.5 mm, 5 mm, or 10 mm.

[0050] The electrode assembly of this utility model sets the distance a1 between the edge of one side of the composite region 5 and the edge of one side of the overlapping region 4 and the distance a2 between the edge of the other side of the composite region 5 and the edge of the other side of the overlapping region 4 within the above range. This allows the required size of the composite region 5 to be met while making full use of the overlapping region 4, thereby meeting the composite requirements of the first diaphragm 2 and the second diaphragm 3.

[0051] In some embodiments, a1 and a2 satisfy a1-a2=±(0-9.9)mm.

[0052] It is understandable that when a1=a2, a1-a2=0, that is, the composite region 5 is centered in the width direction of the first diaphragm 2.

[0053] Meanwhile, the present invention enables a1 and a2 to satisfy a1-a2=±(0-9.9)mm, which can improve the processing tolerance of the composite region 5 and reduce the processing difficulty.

[0054] In some embodiments, in the length direction of the first diaphragm 2, the distance b1 between the edge of the composite region 5 adjacent to the first winding start 101 and the edge of the overlapping region 4 adjacent to the first winding start 101 satisfies 0≤b1≤10mm. Preferably, the distance b1 between the edge of the composite region 5 adjacent to the first winding start 101 and the edge of the overlapping region 4 adjacent to the first winding start 101 is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0055] The distance b2 between the edge of the composite region 5 away from the first winding start 101 and the edge of the overlapping region 4 away from the first winding start 101 satisfies 0≤b2≤10mm.

[0056] Preferably, the distance b2 between the edge of the composite region 5 away from the first winding start 101 and the edge of the overlapping region 4 away from the first winding start 101 is 0.1mm, 0.5mm, 2.5mm, 5mm, or 10mm.

[0057] The electrode assembly of this utility model sets the distance b1 between the edge of the composite region 5 adjacent to the first winding start 101 and the edge of the overlapping region 4 adjacent to the first winding start 101 and the distance b2 between the edge of the composite region 5 away from the first winding start 101 and the edge of the overlapping region 4 away from the first winding start 101 to the range described above. This allows the required size of the composite region 5 to be met while making full use of the overlapping region 4, thereby meeting the composite requirements of the first diaphragm 2 and the second diaphragm 3.

[0058] In some embodiments, b1 and b2 satisfy b1-b2=±(0-10)mm.

[0059] It is understandable that when b1=b2, b1-b2=0, that is, the composite region 5 is centered in the length direction of the first diaphragm 2.

[0060] Meanwhile, the present invention enables b1 and b2 to satisfy b1-b2=±(0-10)mm, which can improve the processing tolerance of the composite region 5 and reduce the processing difficulty.

[0061] In some embodiments, the composite region 5 is provided with a plurality of composite parts 501, and the composite parts 501 are formed by combining a portion of the first diaphragm 2 and a portion of the second diaphragm 3. The length E of the projection of the composite part 501 in the width direction of the first diaphragm 2 satisfies 0.5mm≤E≤10mm, and the total length Etotal of the projection of the multiple composite parts in the width direction of the first diaphragm 2 satisfies 0.05≤Etotal / A≤1. Preferably, the length E of the projection in the width direction of the first diaphragm 2 is 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, or 10.0 mm.

[0062] It is understandable that the total length E of the projections of multiple projections in the width direction of the first diaphragm 2 can be divided into two cases. Firstly, the projections of the multiple composite parts 501 in the width direction of the first diaphragm 2 do not overlap with each other. The total length E of the projections of the multiple composite parts 501 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 composite parts 501 in the width direction of the first diaphragm 2. Secondly, the projections of multiple composite parts 501 in the width direction of the first diaphragm 2 overlap. The total length E of the projections of multiple composite parts 501 in the width direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple composite parts 501 in the width direction of the first diaphragm 2. For example, if the projections of two composite parts 501 in the width direction of the first diaphragm 2 overlap, then the total length E of the projections of the two composite parts 501 in 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 composite parts 501 in the overlapping portion in the width direction of the projection of the two composite parts 501 in the width direction of the first diaphragm 2.

[0063] The length F of the projection of the composite part 501 in the length direction of the first diaphragm 2 satisfies 0.5mm≤F≤100mm, and the total length Ftotal of the projection of the multiple composite parts 501 in the length direction of the first diaphragm 2 satisfies 0.05≤Ftotal / B≤1.

[0064] Preferably, the length F of the composite part 501 projected in the longitudinal direction of the first diaphragm 2 is 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, 5.5 mm, 6.0 mm, 6.5 mm, 7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm, 9.0 mm, 9.5 mm, or 10.0 mm.

[0065] It is understandable that the total length F of the projections of the multiple composite parts 501 along the length direction of the first diaphragm 2 can be divided into two cases. Firstly, the projections of the multiple composite parts 501 along the length direction of the first diaphragm 2 do not overlap with each other. The total length F of the projections of the multiple composite parts 501 along the length direction of the first diaphragm 2 can be understood as the sum of the lengths F1 of the projections of the multiple composite parts 501 along the length direction of the first diaphragm 2. Secondly, the projections of multiple composite parts 501 in the length direction of the first diaphragm 2 overlap. The total length F of the projections of multiple composite parts 501 in the length direction of the first diaphragm 2 can be understood as the length of the union of the projections of multiple composite parts 501 in the length direction of the first diaphragm 2. For example, if the projections of two composite parts 501 in the length direction of the first diaphragm 2 overlap, then the total length F of the projections of the two composite parts 501 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 composite parts 501 in the overlapping portion in the length direction of the first diaphragm 2.

[0066] The electrode assembly of this utility model embodiment, by providing multiple composite parts 501, sets the length E of the projection of the composite part 501 in the width direction of the first diaphragm 2 and the length F of the projection of the composite part 501 in the length direction of the first diaphragm 2 to the aforementioned range, while ensuring that the sum of the lengths E of the projections of the multiple composite parts 501 in the width direction of the first diaphragm 2, E_total, satisfies 0.05≤E_total / A≤1 and that the sum of the lengths F of the projections of the multiple composite parts 501 in the length direction of the first diaphragm 2, F_total, satisfies 0.05≤F_total / B≤1, thereby reducing the composite cost while meeting the composite requirements of the composite region 5.

[0067] In some embodiments, the peel strength of the composite region 5 is 0.01~5.0 N / cm.

[0068] Furthermore, the peel strength test standard used to test the peel strength of the composite region 5 is ASTM D3330. Specifically, the first diaphragm 2 and the second diaphragm 3 are peeled through the composite region 5 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 composite region 5 is calculated.

[0069] It is understandable that the greater the peel strength of composite region 5, the higher the required composite cost, and vice versa.

[0070] The electrode assembly of this utility model reduces the composite cost of the composite region 5 by setting the peel strength of the composite region 5 to 0.01~5.0 N / cm, while meeting the composite requirements of the first diaphragm 2 and the first diaphragm 3.

[0071] This utility model also provides a wound battery cell.

[0072] like Figure 2As shown, the wound battery cell of this utility model embodiment includes the electrode assembly and the second electrode 6 as described in the above embodiment, wherein one of the first electrode 1 and the second electrode 6 is a positive electrode and the other electrode is a negative electrode. The innermost ring of the first electrode 1 includes a first corner segment 102, which is positioned opposite to the second winding start end 601 of the second electrode 6; the innermost ring of the second electrode 6 includes a second corner segment 602, which is positioned opposite to the first winding start end 101 of the first electrode 1.

[0073] The battery cell of this utility model embodiment, by setting the electrode assembly as described in the above embodiment, connects the heads of the separators on both sides of the positive or negative electrode to form a whole, which can avoid the problem of separator folding or even leakage of the electrode during the winding and core pulling process, thereby greatly improving the winding quality and performance of the battery cell.

[0074] This utility model also provides a battery.

[0075] The battery of this utility model embodiment includes the wound cell described in the above embodiment.

[0076] 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. An electrode assembly, characterized in that, include: The first electrode (1) has a first winding start end (101). 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); Along the length of the first electrode (1), the first diaphragm (2) has a first region (201) extending beyond the first winding start (101), and the second diaphragm (3) has a second region (301) extending beyond the first winding start (101); the first region (201) is connected to the second region (301).

2. The electrode assembly according to claim 1, characterized in that, The first region (201) and the second region (301) have overlapping regions (4) in the thickness direction of the first electrode (1), and a composite region (5) is provided in the overlapping region (4) to connect the first diaphragm (2) and the second diaphragm (3).

3. The electrode assembly according to claim 2, characterized in that, The length A of the projection of the overlapping region (4) onto the width direction of the first diaphragm (2) satisfies 1.0 mm ≤ A ≤ 10 mm, and / or The projection length B of the overlapping region (4) in the length direction of the first diaphragm (2) satisfies 5.0mm≤B≤300mm.

4. The electrode assembly according to claim 2, characterized in that, The length C of the composite region (5) projected onto the width direction of the first diaphragm (2) satisfies 0.5mm ≤ C ≤ A, and / or The length D of the composite region (5) projected onto the length of the first diaphragm (2) satisfies 5% ≤ D / B ≤ 100%.

5. The electrode assembly according to claim 2, characterized in that, In the width direction of the first diaphragm (2), the distance a1 between the edge of one side of the composite region (5) and the edge of one side of the overlapping region (4) satisfies 0.1mm≤a1≤10mm. The distance a2 between the edge of the composite region (5) on the other side and the edge of the overlapping region (4) on the other side satisfies 0.1mm≤a2≤10mm.

6. The electrode assembly according to claim 5, characterized in that, The a1 and a2 satisfy a1-a2=±(0-9.9)mm.

7. The electrode assembly according to claim 2, characterized in that, In the length direction of the first diaphragm (2), the distance b1 between the edge of the composite region (5) adjacent to the first winding start (101) and the edge of the overlapping region (4) adjacent to the first winding start (101) satisfies 0≤b1≤10mm; The distance b2 between the edge of the composite region (5) away from the first winding start (101) and the edge of the overlapping region (4) away from the first winding start (101) satisfies 0 ≤ b2 ≤ 10 mm.

8. The electrode assembly according to claim 7, characterized in that, The b1 and b2 satisfy b1-b2=±(0-10)mm.

9. The electrode assembly according to claim 3, characterized in that, The composite region (5) is provided with a plurality of composite parts (501), and the composite parts (501) are formed by combining a portion of the first diaphragm (2) and a portion of the second diaphragm (3); The length E of the projection of the composite part (501) onto the width direction of the first diaphragm (2) satisfies 0.5mm≤E≤10mm, and the total length Etotal of the projection of the plurality of composite parts (501) onto the width direction of the first diaphragm (2) satisfies 0.05≤Etotal / A≤1; The length F of the projection of the composite part (501) onto the length direction of the first diaphragm (2) satisfies 0.5mm≤F≤100mm, and the total length Ftotal of the projections of the plurality of composite parts (501) onto the length direction of the first diaphragm (2) satisfies 0.05≤Ftotal / B≤1.

10. The electrode assembly according to claim 9, characterized in that, The projections of the plurality of composite portions (501) onto the width direction of the first diaphragm (2) do not coincide; and / or, The projections of the plurality of composite parts (501) onto the length direction of the first diaphragm (2) do not overlap.

11. The electrode assembly according to claim 2, characterized in that, The peel strength of the composite region (5) is 0.01~5.0 N / cm.

12. A wound battery cell, characterized in that, Includes the electrode assembly and the second electrode (6) as described in any one of claims 1-11, wherein one of the first electrode (1) and the second electrode (6) is a positive electrode and the other is a negative electrode; The innermost ring of the first electrode (1) includes a first corner segment (102), which is disposed opposite to the second winding start end (601) of the second electrode (6); the innermost ring of the second electrode (6) includes a second corner segment (602), which is disposed opposite to the first winding start end (101) of the first electrode (1).

13. A battery, characterized in that, Including the wound battery cell as described in claim 12.

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