Pole piece, winding battery cell and battery

Abstract

The utility model discloses a pole piece, winding battery cell and battery, the pole piece is used for winding battery cell, the pole piece includes: the body, the outer edge of the body includes two oppositely arranged first sides and two oppositely arranged second sides, each first side extends along the winding direction of winding battery cell, and each second side extends along the winding direction of winding battery cell. Each second edge is connected with the two first edges at the same time, an included angle theta is formed between at least one part of at least one second edge and the winding direction of the winding battery cell, and theta is not equal to 90 degrees. According to the pole piece disclosed by the utility model, the shape of the pole piece at the winding position of the inner ring of the roll core is processed, and the stress caused by expansion and shrinkage of the pole piece in the circulation process of the battery core is dispersed and eliminated, so that the collapse deformation of the central hole is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and more specifically, to a pole piece, a wound battery core and a battery. Background Art

[0002] The existing large cylindrical lithium-ion battery cells are processed and manufactured in the same way as traditional cylindrical battery cells. The core needs to be made through a winding process, that is, the diaphragm is fixed by a winding needle, and then the diaphragm, negative electrode sheet, and positive electrode sheet are assembled into a cylindrical core under continuous rotation.

[0003] As the market demand for battery cell energy and power density continues to increase, positive and negative electrode active materials with higher energy density, such as high-nickel ternary materials (NCM) and silicon system materials, have begun to be used in cylindrical lithium-ion batteries.

[0004] In the actual production of pole pieces, a slurry made of active materials, conductive agents, binders and additives is required and coated on aluminum foil and copper foil using coating technology. The high-nickel ternary system material on the positive pole piece will have a certain volume contraction and expansion in the high voltage section during the charge and discharge process, and the silicon system material on the negative pole piece will produce a large volume expansion and contraction during the charge and discharge process, both of which will produce a certain stress on the pole piece. Since the center hole area of ​​the winding core has no support, under the combined influence of the above reasons, the inner ring pole piece of the winding core is prone to deformation during the charge and discharge of the battery cell, resulting in the collapse of the center hole. Among them, the collapse and deformation of the center hole will cause the positive and negative pole pieces to detach or even partially rupture, and then produce lithium deposition, and the capacity of the battery cell will drop rapidly. In severe cases, the pole piece may pierce the diaphragm and cause an internal short circuit. Utility Model Content

[0005] One purpose of the present invention is to provide a pole piece that can at least solve the problem in the prior art that the central hole of a cylindrical battery cell is prone to collapse and deformation, resulting in a rapid decrease in capacity.

[0006] Another object of the present invention is to provide a wound battery cell comprising the above-mentioned pole piece.

[0007] Another object of the present invention is to provide a battery comprising the above-mentioned wound battery cell.

[0008] In order to achieve the above objectives, the present utility model provides the following technical solutions.

[0009] According to the pole piece of the embodiment of the first aspect of the present invention, the pole piece is used for winding the battery cell, and the pole piece includes: a main body, the outer edge of the main body includes two oppositely arranged first edges and two oppositely arranged second edges, each of the first edges extends along the winding direction of the wound battery cell, and each of the second edges is simultaneously connected to two of the first edges, wherein at least a portion of at least one of the second edges has an angle θ with the winding direction of the wound battery cell, and θ≠90°.

[0010] Optionally, the second side is a straight side, and θ corresponding to the second side satisfies: 45°≤θ≤135°.

[0011] Optionally, the second edge includes: a first edge, one end of which is connected to one of the first edges; a second edge, one end of which is connected to the other end of the first edge, the other end of the second edge is connected to another of the first edges, and the angle θ corresponding to at least one of the first edge and the second edge is ≠90°; wherein, at least one of the first edge and the second edge is a straight edge or a curved edge.

[0012] Optionally, the first edge and the second edge are respectively straight edges and cooperate to form a protrusion, the θ corresponding to the first edge satisfies 45°≤θ≤135°, and the θ corresponding to the second edge satisfies 90°, and along the arrangement direction of the two first edges, the height of the first edge is greater than the height of the second edge.

[0013] Optionally, the first edge and the second edge are respectively straight edges and cooperate to form a protrusion, the first edge and the second edge respectively correspond to θ≠90°, θ of the first edge satisfies: 45°≤θ<90°, and θ of the second edge satisfies: 90°≤(180°-θ)<135°.

[0014] Optionally, the second edge further includes: a third edge, one end of the third edge is connected to one end of the first edge or the other end of the second edge, the other end of the third edge is connected to the first edge, and θ corresponding to the third edge is 90°.

[0015] Optionally, the first edge and the second edge are respectively straight edges, and the two cooperate to form a recessed portion, and the θ corresponding to the first edge satisfies: 90°≤θ<135°, and the θ corresponding to the second edge satisfies: 45°≤θ<90°.

[0016] Optionally, one end of the third edge is connected to the other end of the second edge, θ corresponding to the first edge and the third edge respectively is 90°, and α corresponding to the second edge satisfies: 45°≤θ≤135°.

[0017] According to the second aspect of the present invention, the wound battery cell includes a positive electrode sheet, a negative electrode sheet and a separator located between the positive electrode sheet and the negative electrode sheet. At least one of the positive electrode sheet and the negative electrode sheet is any of the above-mentioned electrodes, and the positive electrode sheet is the same as or different from the negative electrode sheet.

[0018] A battery according to an embodiment of the third aspect of the present invention includes any of the above-mentioned wound battery cells.

[0019] According to the pole piece of the embodiment of the present invention, at least a portion of at least one second side has an angle θ with the winding direction of the wound battery cell, θ≠90°, that is, the shape of the pole piece at the winding position of the inner circle of the winding core is processed to disperse and eliminate the stress caused by the expansion and contraction of the pole piece during the battery cell cycle, thereby preventing the occurrence of collapse and deformation of the center hole. The wound battery cell using the pole piece of this embodiment not only does not require the introduction of an additional support tube in the center hole, which can avoid the risk of damaging the winding core during the insertion of the support tube; it also does not require the introduction of additional glue or support sheets at the entry position of the inner circle of the winding core, which can improve the winding yield and efficiency; in addition, it can reduce the risk of deformation of the pole piece at the entry position and collapse of the center hole without changing or significantly changing the coating and winding process.

[0020] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0022] Figure 1 This is a schematic diagram of the winding core in the prior art;

[0023] Figure 2 This is a schematic diagram of a winding core in a winding position according to an embodiment of the present invention;

[0024] Figure 3 Schematic diagram of a winding core in a winding position according to another embodiment of the present invention;

[0025] Figure 4 Schematic diagram of a winding core in a winding position according to another embodiment of the present invention;

[0026] Figure 5 Schematic diagram of a winding core in a winding position according to another embodiment of the present invention;

[0027] Figure 6Schematic diagram of a winding core in a winding position according to another embodiment of the present invention;

[0028] Figure 7 Schematic diagram of a winding core in a winding position according to another embodiment of the present invention;

[0029] Figure 8 This is a schematic diagram of a winding core in place according to another embodiment of the present invention.

[0030] Figure Numbers

[0031] Winding the battery cell 100;

[0032] First side 10; second side 20; first edge 21; second edge 22; third edge 23; protrusion 24; recess 25;

[0033] Positive electrode tab area 31; positive electrode coating area 32; separator 33; negative electrode tab area 34; negative electrode coating area 35;

[0034] The battery cell 100' is wound. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0036] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.

[0037] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0038] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0039] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0040] The pole piece according to the embodiment of the present utility model is described in detail below with reference to the accompanying drawings.

[0041] like Figures 2 to 8 As shown, the pole piece according to the embodiment of the present invention is used for winding a battery core, and the pole piece includes a body.

[0042] Specifically, the outer edge of the body includes two opposing first edges 10 and two opposing second edges 20. Each first edge 10 extends along the winding direction of the wound battery cell, and each second edge 20 is connected to both first edges 10. At least a portion of at least one second edge 20 forms an angle θ with the winding direction of the wound battery cell, where θ ≠ 90°. The winding direction is indicated by the arrows in the accompanying drawings.

[0043] In other words, the pole piece according to an embodiment of the present invention can be installed in a wound battery cell, wherein the pole piece includes a body having an outer edge, for example, the outer surface of the body includes a side surface and an outer edge, the outer edge is arranged around the outer contour of the side surface, and the side surface can be coated with an active material.

[0044] The outer edge of the body may include two first edges 10, and the two first edges 10 may be arranged relative to each other, for example, relative to each other in the width direction of the pole piece. For example, the upper edge and the lower edge of the body are both first edges 10. Moreover, the first edge 10 extends roughly along the winding direction of the wound battery cell. In addition, the outer edge of the body may also include two second edges 20, for example, the outer edges of the two ends of the flattened body in the longitudinal direction are the second edges 20. Each second edge 20 is directly or indirectly connected to the two first edges 10 at the same time. For example, the upper end of the second edge 20 is connected to the right end of the upper first edge 10, and the lower end of the second edge 20 is connected to the right end of the lower first edge 10.

[0045] It should be noted that at least a portion of at least one second side 20 forms an angle θ with the winding direction of the wound battery cell, where θ≠90°. In other words, either one second side 20 or both second sides 20 may satisfy θ≠90°. For ease of explanation, the following description uses a single second side 20 as an example.

[0046] When applying the electrode sheet to a wound cell, during the assembly process, the separator can be first clamped by a winding needle. After the separator is wound a certain number of times, the negative electrode sheet is inserted into the outer separator gap, and the positive electrode sheet is inserted into the inner separator gap. The separator and the positive and negative electrode sheets are then wound again until the winding is complete. The winding needle is then withdrawn to form the center hole. During this process, the negative electrode coating area can completely cover the positive electrode coating area, preventing lithium plating.

[0047] In the prior art, Figure 1As shown in the figure, the positive and negative electrode sheet insertion points, i.e., the ends of the positive and negative electrode sheets inserted into the winding core, are squared by cutting with a straight knife perpendicular to the winding direction. In this case, when the stress generated by the expansion and contraction of the electrode sheets during the charging and discharging process of the battery cell is transmitted to the electrode sheet insertion point, it will be concentrated in the center. Due to the presence of the center hole of the winding core, the electrode sheets on the inner circle of the winding core lack support, resulting in excessive stress in the center of the electrode sheet insertion point, deformation and warping, and the collapse of the center hole.

[0048] In contrast, in this embodiment, for example Figure 6 In the distribution design of the positive electrode tab area 31, the positive electrode coating area 32, the separator 33, the negative electrode tab area 34 and the negative electrode coating area 35 of an embodiment shown, at least a portion of at least one second edge 20 has an angle θ with the winding direction of the wound battery cell, θ≠90°, and the shape of the positive and negative electrode sheets is trimmed at the insertion position to alleviate stress concentration at the insertion position of the winding core, thereby reducing the risk of collapse of the center hole.

[0049] In this embodiment, at least a portion of at least one second side 20 forms an angle θ with the winding direction of the wound cell, where θ≠90°. That is, the shape of the pole piece at the inner ring of the winding core is processed to disperse and eliminate the stress caused by the expansion and contraction of the pole piece during the battery cell cycle, thereby preventing the occurrence of collapse and deformation of the center hole. The wound battery cell using the pole piece of this embodiment not only does not require the introduction of an additional support tube in the center hole, thus avoiding the risk of damage to the core during the insertion of the support tube; it also does not require the introduction of additional glue or support sheets at the inner ring of the winding core, thus improving the winding yield and efficiency. In addition, it can reduce the risk of pole piece deformation at the entry point and center hole collapse without changing or significantly changing the coating and winding process.

[0050] According to one embodiment of the present invention, the second side 20 is a straight side, and the angle θ corresponding to the second side 20 satisfies: 45°≤θ≤135°, and θ≠90°. In other words, the pole piece of this embodiment is cut into a beveled side at a certain angle θ with respect to the winding direction at the insertion position, and the angle θ satisfies 45°≤α≤135°. For example, Figure 2 As shown, the second side 20 is inclined to the lower right, and the angle between the second side 20 of the positive electrode sheet and the left and right directions is defined as α, and the angle between the second side 20 of the negative electrode sheet and the left and right directions is defined as α', where 45°≤α≤135°, 45°≤α'≤135°; where α and α' are the same or different, and are not limited here. In this embodiment, the second side 20 is a straight edge, and the θ corresponding to the second side 20 satisfies the following: 45°≤θ≤135°, for example, θ is 45°, 50°, 60°, 70°, 80°, 85°, 95°, 100°, 110°, 120°, 130° or 135°, etc., which can effectively reduce the risk of deformation of the electrode sheet at the time of insertion and collapse of the center hole.

[0051] In some specific embodiments of the present invention, the second edge 20 includes: a first edge 21 and a second edge 22, one end of the first edge 21 is connected to one first edge 10, one end of the second edge 22 is connected to the other end of the first edge 21, and the other end of the second edge 22 is connected to another first edge 10, and at least one of the first edge 21 and the second edge 22 corresponds to θ≠90°. For example, Figure 3 As shown, the first edge 21 corresponds to θ≠90°, and the second edge 22 corresponds to θ=90°. In this embodiment, by adopting that the second side 20 includes the first edge 21 and the second edge 22, and at least one of the first edge 21 and the second edge 22 corresponds to θ≠90°, the risk of deformation of the pole piece at the insertion position and collapse of the center hole can be effectively reduced.

[0052] According to one embodiment of the present invention, at least one of the first edge 21 and the second edge 22 is a straight edge or a curved edge. Figure 3 and Figure 4 As shown. Using straight edges facilitates forming 90° or other angles. Using curved edges reduces the risk of sharp edges piercing the separator 33 during the cell's charge and discharge process, causing a short circuit. During manufacturing, sharp corners can be rounded. Furthermore, when using a design perpendicular to the winding direction, such as when the first edge 21 or the second edge 22 is perpendicular to the winding direction, the cut edges can also be optimized to prevent sharp edges from piercing the separator 33 during the charge and discharge process, causing a short circuit.

[0053] According to one embodiment of the present invention, the first edge 21 and the second edge 22 are respectively straight edges and cooperate to form a protrusion 24. The angle θ corresponding to the first edge 21 satisfies 45°≤θ≤135°, and the angle θ corresponding to the second edge 22 is 90°. Along the arrangement direction of the two first edges 10, the height of the first edge 21 is greater than the height of the second edge 22. The height here refers to the height difference between the two ends of the first edge 10 and the height difference between the two ends of the second edge 20. During manufacturing, the two ends of the pole piece are misaligned at the insertion position, and a portion is cut into a straight edge (second edge 22) perpendicular to the winding direction. The center area of ​​the pole piece can be cut into a beveled edge (first edge 21) with a certain inclination angle θ to the winding direction. The angle θ satisfies 45°≤θ≤135°, for example, θ is 45°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120° or 135°. In this embodiment, by adopting an arrangement direction along the two first sides 10 in which the height of the first edge 21 is greater than the height of the second edge 22 , the risk of deformation of the pole piece at the insertion position and collapse of the center hole can be further reduced.

[0054] In some specific embodiments of the present invention, the second edge 20 has a protrusion 24, the first edge 21 and the second edge 22 are respectively straight edges and can cooperate to form the protrusion 24, the first edge 21 and the second edge 22 respectively correspond to θ≠90°, the θ of the first edge 21 satisfies: 45°≤θ<90°, and the θ of the second edge 22 satisfies: 90°≤(180°-θ)<135°. Figure 6 As shown, the lower end of the first edge 21 is inclined toward the lower right, and the lower end of the second edge 22 is inclined toward the lower left. The first edge 21 and the second edge 22 form a ">"-type structure. During manufacturing, a convex scheme can be achieved by beveling on both sides. For example, the pole piece is beveled twice at the insertion position to form a protruding triangle. The angles α and β of the two bevels satisfy 45°≤α<90° and 90°≤β<135°. For example, α is 45°, 50°, 60°, 70°, 80°, 85° or 89°, and β is 90°, 95°, 100°, 110°, 120°, 125°, 130° or 135°. In this embodiment, θ of the first edge 21 satisfies: 45°≤θ<90°, and θ of the second edge 22 meets: 90°≤(180°-θ)<135°, which can effectively reduce the risk of deformation of the pole piece at the insertion position and collapse of the center hole.

[0055] According to one embodiment of the present invention, the second edge 20 further includes a third edge 23, one end of the third edge 23 is connected to one end of the first edge 21 or the other end of the second edge 22, and the other end of the third edge 23 is connected to the first edge 10, and the angle θ corresponding to the third edge 23 is 90°. For example, the second edge 20 is composed of a first edge 21, a second edge 22, and a third edge 23 connected in sequence, or a third edge 23, a first edge 21, a second edge 22, and another third edge 23 connected in sequence, etc. In this embodiment, the angle θ corresponding to the third edge 23 is 90°, which can reduce the risk of a sharp tip piercing the diaphragm 33 and causing a short circuit during the charging and discharging process of the battery cell.

[0056] Optionally, the first edge 21, the second edge 22 or the third edge 23 directly connected to the first edge 10 adopts θ=90°, which can reduce the risk of the sharp tip piercing the diaphragm 33 and causing a short circuit during the charging and discharging process of the battery cell. During manufacturing, when cutting produces a sharp angle on the electrode, the sharp angle area can be cut off to form a straight edge perpendicular to the winding direction.

[0057] In some specific embodiments of the present invention, the second edge 20 has a recessed portion 25. The first edge 21 and the second edge 22 are both linear edges that can cooperate to form the recessed portion 25. The angle θ corresponding to the first edge 21 satisfies the following: 90°≤θ<135°, and the angle θ corresponding to the second edge 22 satisfies the following: 45°≤θ<90°. For example, the second edge 20 is composed of a third edge 23, a first edge 21, a second edge 22, and another third edge 23. The third edge 23 is perpendicular to the winding core direction. The lower end of the first edge 21 extends to the lower left, and the lower end of the second edge 22 extends to the lower right. The first edge 21 and the second edge 22 form an inwardly recessed groove structure, i.e., the recessed portion 25. For another example, the second edge 20 is composed of a first edge 21 and a second edge 22. The first edge 21 and the second edge 22 form an inwardly recessed groove structure, i.e., the recessed portion 25. The recessed portion 25 refers to a groove structure formed on the second edge 20 that is recessed toward the interior of the pole piece. In this embodiment, the second edge 20 has a recessed portion 25, and the short portion of the pole piece can be roughly in the shape of an inverted "∑". During production, an inward convex structure can be formed by beveling on both sides. For example, the pole piece is beveled twice at the insertion position to form an inward concave "∑"-shaped area, and the angles α and β of the two bevels satisfy 90°≤α<135°, 45°≤β<90°.

[0058] According to one embodiment of the present invention, Figure 5 As shown, one end of the third edge 23 is connected to the other end of the second edge 22 , the first edge 21 and the third edge 23 respectively correspond to θ=90°, and the α corresponding to the second edge 22 meets the following conditions: 45°≤θ≤135°.

[0059] The present invention also discloses a wound battery cell, which includes the electrode sheet of any of the above-mentioned embodiments. Specifically, the wound battery cell includes a positive electrode sheet, a negative electrode sheet and a separator 33 located between the positive electrode sheet and the negative electrode sheet, at least one of the positive electrode sheet and the negative electrode sheet is the electrode sheet of any of the above-mentioned embodiments, and the positive electrode sheet is the same as or different from the negative electrode sheet, for example, the bevel angles used by the positive electrode sheet and the negative electrode sheet can be the same or different; for example, in the same winding core, the bevel angles α and β used by the positive electrode sheet correspond to the bevel angles α' and β' used by the negative electrode sheet, and the two can be the same or different. In addition, in actual applications, the schemes of the above multiple embodiments can be used on the positive and negative electrode sheets, or the schemes of the above embodiments can be combined with the traditional straight knife cutting scheme.

[0060] In this embodiment, since the wound battery cell includes the electrode of any of the above-mentioned embodiments, the electrode of the embodiment of the utility model can change the stress concentration at the electrode entry point during the charging and discharging of the battery cell by adjusting the shape of the electrode at the entry point of the winding core, thereby reducing the risk of deformation of the electrode at the entry point and collapse of the center hole. Therefore, the wound battery cell of the embodiment of the utility model also has the same advantages, which will not be elaborated here.

[0061] The present invention also discloses a battery, which includes a wound battery cell according to any of the above embodiments. The battery may include a cylindrical battery, etc. According to the battery of the embodiment of the present invention, by adjusting the shape of the pole piece at the winding position of the core, the stress concentration at the pole piece entry position during the battery charging and discharging process is changed, and the shape of the pole piece at the entry position, and thus the risk of the center hole collapsing, is reduced. It also reduces the risk of the center hole collapsing, which can improve the battery cycle life and battery safety. It also reduces the risk of the center hole collapsing, and the battery design can be compatible with high-nickel ternary materials (NCM) with higher nickel content and negative electrodes with higher silicon-based material content, which is beneficial to improving the energy density and power density of the battery.

[0062] Although some specific embodiments of the present invention have been described in detail through examples, those skilled in the art will appreciate that the above examples are for illustration only and are not intended to limit the scope of the present invention. Those skilled in the art will appreciate that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A pole piece, characterized in that: The pole piece is used for winding the battery core, and the pole piece includes: A body, wherein the outer edge of the body comprises two oppositely arranged first sides (10) and two oppositely arranged second sides (20), each of the first sides (10) extends along the winding direction of the wound battery cell, and each of the second sides (20) is simultaneously connected to the two first sides (10), wherein at least a portion of at least one of the second sides (20) has an angle θ with the winding direction of the wound battery cell, and θ≠90°.

2. The pole piece according to claim 1, characterized in that: The second side (20) is a straight side, and the angle θ corresponding to the second side (20) satisfies: 45°≤θ≤135°.

3. The pole piece according to claim 1, characterized in that: The second side (20) comprises: a first edge (21), one end of the first edge (21) being connected to one of the first sides (10); a second edge (22), one end of the second edge (22) being connected to the other end of the first edge (21), the other end of the second edge (22) being connected to another first edge (10), and at least one of the first edge (21) and the second edge (22) corresponding to θ≠90°; Wherein, at least one of the first edge (21) and the second edge (22) is a straight edge or a curved edge.

4. The pole piece according to claim 3, characterized in that: The first edge (21) and the second edge (22) are respectively straight edges and cooperate to form a protrusion, the angle θ corresponding to the first edge (21) satisfies 45°≤θ≤135°, and the angle θ corresponding to the second edge (22) satisfies 90°, and along the arrangement direction of the two first edges (10), the height of the first edge (21) is greater than the height of the second edge (22).

5. The pole piece according to claim 3, characterized in that: The first edge (21) and the second edge (22) are respectively straight edges and cooperate to form a protrusion (24); the first edge (21) and the second edge (22) respectively correspond to θ≠90°; the θ of the first edge (21) satisfies: 45°≤θ<90°; the θ of the second edge (22) satisfies: 90°≤(180°-θ)<135°.

6. The pole piece according to claim 3, characterized in that: The second side (20) further comprises: A third edge, one end of the third edge is connected to one end of the first edge (21) or the other end of the second edge (22), the other end of the third edge is connected to the first side (10), and the angle θ corresponding to the third edge is 90°.

7. The pole piece according to claim 6, characterized in that: The first edge (21) and the second edge (22) are respectively straight edges and cooperate to form a recessed portion (25), the θ corresponding to the first edge (21) satisfies: 90°≤θ<135°, and the θ corresponding to the second edge (22) satisfies: 45°≤θ<90°.

8. The pole piece according to claim 7, characterized in that: One end of the third edge is connected to the other end of the second edge (22), the first edge (21) and the third edge respectively correspond to θ=90°, and the second edge (22) corresponds to α that meets the following conditions: 45°≤θ≤135°.

9. A wound battery cell (100), characterized in that: The invention comprises a positive electrode sheet, a negative electrode sheet and a separator (33) located between the positive electrode sheet and the negative electrode sheet, at least one of the positive electrode sheet and the negative electrode sheet is a sheet according to any one of claims 1 to 8, and the positive electrode sheet is the same as or different from the negative electrode sheet.

10. A battery, characterized in that: It comprises the wound battery cell (100) according to claim 9.

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