Battery cell pole piece structure, battery cell and battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell pole piece structure, a battery cell and a battery. The battery cell pole piece structure comprises a current collector and an active material layer connected to at least one surface of the current collector, the surface of the active material layer along the width direction is provided with at least one thinned recess; the active material layer is also provided with a tab groove; the tab groove is arranged in a penetrating manner along the thickness direction of the active material layer; the tab grooves are used for mounting tabs; and the bottom of the tab groove extends to the surface of the current collector. According to the utility model, the probability of lithium separation in a lithium ion partial region can be reduced; therefore, the safety and stability of the structure in use are improved, and the energy density is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the technical field, and in particular relates to a battery cell pole piece structure, a battery cell and a battery. Background Art

[0002] Lithium-ion batteries are secondary batteries. Due to their numerous advantages, including high energy density, low self-discharge rate, high potential difference, and long cycle life, they are widely used in consumer electronics, new energy vehicles, energy storage devices, and other technical fields. As technology continues to evolve, consumer electronics and other products are placing increasingly high demands on the cycle life and fast charging capabilities of lithium batteries. To meet these demands, the number of charge and discharge cycles and charge rates of lithium batteries are increasing.

[0003] However, during high-rate charging, the current density per unit area of the electrode surface is high, that is, the lithium ion concentration is high, which can easily cause lithium deposition in some areas of the battery cell, thereby causing the battery cell performance to fail and reducing its safety and stability. Utility Model Content

[0004] The purpose of the present invention is to provide a battery cell pole piece structure, a battery cell and a battery in view of the deficiencies in the prior art, which can solve the technical problems of low safety and stability in the use of the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A battery cell electrode structure includes a current collector and an active material layer connected to at least one surface of the current collector; the active material layer is provided with at least one thinned depression along the width direction of the surface; the active material layer is also provided with a tab groove; the tab groove is arranged to penetrate along the thickness direction of the active material layer; the tab groove is used to install the tab; and the bottom of the tab groove extends to the surface of the current collector.

[0007] Preferably, the thinning recess includes at least one first recess; the first recess is arranged parallel to the width direction of the active material layer; and the first recess is arranged throughout the width direction of the active material layer.

[0008] Preferably, when the battery cell electrode structure is in a wound state, the first recess is arranged at a turning position; and / or, at most a portion of the first recess is arranged at a straight position.

[0009] Preferably, the relationship between the thickness H2 of the first recess and the thickness H1 of the battery cell electrode structure satisfies: H2=H1*A; wherein A=(8%-14%).

[0010] Preferably, the thinning recess further includes at least one second recess; the second recess is provided on at least one side in the width direction of the active material layer; and the second recess abuts against an edge in the width direction of the active material layer.

[0011] Preferably, the value range of the width L1 of the second recess satisfies: L1 = 5 to 10 mm;

[0012] And / or, the relationship between the thickness H3 of the second recess and the thickness H1 of the battery cell electrode structure satisfies: H3=H1*B; wherein B=(8%-14%).

[0013] Preferably, a protective layer is further provided in the tab groove; the protective layer is connected to the tab; and the projection of the protective layer toward the current collector covers the portion of the tab groove where the tab is located;

[0014] The relationship between the length of the protective layer and the length D1 of the tab satisfies the following equation: D2-D1≥1mm.

[0015] The utility model also discloses a battery cell, comprising a first pole piece and a second pole piece with opposite polarities and a diaphragm arranged between the first pole piece and the second pole piece; at least one of the first pole piece and the second pole piece is the above-mentioned battery cell pole piece structure.

[0016] Preferably, the total thickness T of the bare cell and the width K of the thinning recess corresponding to the outermost winding satisfy the relationship: π / 3≤K / T≤2π / 3, where T satisfies: 2≤T≤20mm;

[0017] The width of the thinning recess corresponding to n-1 windings satisfies K-1*(2S+A+C);

[0018] The width of the thinning recess corresponding to n-2 circles satisfies K-2*(2S+A+C);

[0019] The width of the thinning recess corresponding to n turns satisfies Kn*(2S+A+C);

[0020] Among them, the total thickness of the bare battery cell is T; the width of the thinning recess corresponding to the outermost winding is K; the total thickness of the first pole piece after winding is C; the total thickness of the second pole piece after winding is A; the total thickness of the diaphragm after winding is S and the number of winding turns is n.

[0021] The utility model also discloses a battery, comprising the battery core.

[0022] The beneficial effect of the present invention is that the present technical solution forms a thinned area on the surface of the coating area by adding one or more thinning depressions on the surface of the active material layer, thereby effectively reducing the amount of lithium ions released from part of the electrode piece, and reducing the probability of lithium deposition in part of the electrode piece; thereby improving the safety and stability of the structure and ensuring its energy density; in addition, on the basis of the thinning depressions provided on the active material layer, a pole ear groove is provided, which can effectively ensure the installation of the pole ear and the reduction of the amount of lithium ions released from part of the electrode piece, thereby reducing the mutual interference between the two, thereby improving the safety and stability of use and ensuring its energy density. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following will refer to the attached Figures 1 to 6 To describe the features, advantages and technical effects of exemplary embodiments of the present invention.

[0024] Figure 1 A top view of a battery cell electrode structure according to one embodiment of the present invention;

[0025] Figure 2 A top view of a battery cell electrode structure according to another embodiment of the present invention;

[0026] Figure 3 This is a front view of a battery cell electrode structure according to another embodiment of the present invention;

[0027] Figure 4 A top view of a battery cell electrode structure according to another embodiment of the present invention;

[0028] Figure 5 This is a front view of a battery cell electrode structure according to another embodiment of the present invention;

[0029] Figure 6 This is a schematic structural diagram of a battery cell according to an embodiment of the present invention.

[0030] In the figure: 100-first pole piece; 200-second pole piece; 300-diaphragm; 1-current collector; 2-active material layer; 3-thinning depression; 31-first depression; 32-second depression; 4-pole tab groove; 5-pole tab; 51-protective layer; 6-turning position; 7-straight position. DETAILED DESCRIPTION

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0032] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0033] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or multiple situations exist. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0035] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0036] The following is combined with Figures 1 to 6 The present invention is further described in detail, but is not intended to limit the present invention.

[0037] like Figure 1 As shown, in one embodiment of the present invention, the battery cell electrode structure includes a current collector 1 and an active material layer 2 connected to at least one surface of the current collector 1; the active material layer 2 is provided with at least one thinning recess 3 along the width direction of the surface; the active material layer 2 is also provided with a tab groove 4; the tab groove 4 is provided along the thickness direction of the active material layer 2; the tab groove 4 is used to install the tab 5; and the bottom of the tab groove 4 extends to the surface of the current collector 1. Figure 1 As shown, the width direction is the Y-axis direction, ie, the direction perpendicular to the coating active material layer 2; and the thickness direction is the Z-axis direction.

[0038] The technical solution of the present invention is to add one or more thinning depressions on the surface of the active material layer to form a thinning area on the surface of the coating area, thereby effectively reducing the amount of lithium ions released from part of the electrode area and reducing the probability of lithium deposition in part of the lithium ion area; thereby improving the safety and stability of the structure and ensuring its energy density; in addition, on the basis of the thinning depressions provided on the active material layer, a pole ear groove is provided, which can effectively ensure the installation of the pole ear and the reduction of the amount of lithium ions released from part of the electrode area, thereby reducing the mutual interference between the two, thereby improving the safety and stability of use and ensuring its energy density.

[0039] In some embodiments, the active material of active material layer 2 is one of lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide. Furthermore, the active material, conductive agent acetylene black, conductive carbon nanotubes, and binder polyvinylidene fluoride (PVDF) are fully dispersed in an N-methylpyrrolidone solvent system at a weight ratio of 98.1:0.45:0.5:0.95 and uniformly coated onto the aluminum current collector to form an active coating area.

[0040] Specifically, in some embodiments, Figure 1 and 2 As shown, the thinning recess 3 includes at least one first recess 31; the first recess 31 is arranged parallel to the width direction of the active material layer 2; and the first recess 31 is arranged throughout the width direction of the active material layer 2. That is, as Figure 2 As shown, the thinned length of the first recess 31 is equal to the width of the electrode; and multiple first recesses 31 are arranged in parallel along the length direction of the active material layer 2 (the length direction is the X-axis, i.e., the direction parallel to the coating direction). This structure effectively reduces the amount of lithium ions released during charging through the guiding effect of the multiple first recesses 31, thereby improving the lithium plating problem of lithium-ion batteries during high-rate charge and discharge, and achieving the effect of improving battery safety.

[0041] Specifically, in some embodiments, Figure 1 and 2 As shown, when the cell electrode structure is in a wound state, the first recess 31 is disposed at the turning position 6; and / or, at most a portion of the first recess 31 is disposed at the straight position 7. That is, after the cell electrode structure is wound into a bare cell, the thinned recess 3 can be disposed entirely in the corner area of the bare cell at the turning position 6. The thinned recess 3 can also be disposed mostly in the corner area of the bare cell, with a small portion extending to the straight area of the straight position 7, to increase the lithium ion guiding effect of the corner, thereby improving the problem of lithium plating at the corner of the lithium-ion battery during high-rate charge and discharge, thereby improving battery safety.

[0042] Specifically, in some embodiments, Figure 2 and 3 As shown, the relationship between the thickness H2 of the first recess 31 and the thickness H1 of the cell electrode structure satisfies the following equation: H2 = H1 * A; where A = (8% to 14%). After the current collector 1 is completely coated with the active material layer 2, the laser cleaning equipment thins the active material layer 2. The thinning thickness is set in a gradient of 8%, 10%, 12%, 14%, etc. of the rolled thickness of the cell electrode structure to form a thinning zone, which is then striped to obtain the cell electrode structure. This structure can achieve a CB value in the thinned zone that is greater than the CB value in the unthinned zone, thereby better improving the lithium deposition phenomenon. If the thickness H2 of the first recess 31 is too large, the CB value will be too large; this will cause the oxidation state of the electrode to increase, which will increase safety hazards. If the thickness H2 of the first recess 31 is too small, the effect of improving lithium deposition cannot be achieved.

[0043] Specifically, in some embodiments, Figure 1 and 4 As shown, the thinning recess 3 further includes at least one second recess 32; the second recess 32 is provided on at least one side of the active material layer 2 in the width direction; and the second recess 32 abuts against the edge of the active material layer 2 in the width direction. Figure 4 As shown, the second recesses 32 are symmetrically arranged on both sides of the active material layer 2 in the width direction and are arranged throughout the length direction of the active material layer 2. In other words, by providing the second recesses 32 at the edges as thinning areas, this structure can increase the lithium ion guidance and aggregation effect at the corners, effectively reducing the amount of lithium ions released from certain areas of the positive electrode sheet, reducing the occurrence of lithium deposition at the edges of the lithium-ion battery, and thus improving the battery safety. In combination with the first recesses 31, the occurrence of lithium deposition at the edges and corners of the lithium-ion battery can also be reduced, thereby improving the battery safety.

[0044] Specifically, in some embodiments, Figure 4 As shown, the width L1 of the second recess 32 satisfies the range of L1 = 5 to 10 mm. L1 can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc. This structure, through the second recess 32 having a reasonable width, can effectively reduce the amount of lithium ions released from certain areas of the positive electrode sheet, reduce the occurrence of lithium deposition at the edges of the lithium-ion battery, and thus improve battery safety.

[0045] Specifically, in some embodiments, Figure 5As shown, the relationship between the thickness H3 of the second recess 32 and the thickness H1 of the cell electrode structure satisfies the following equation: H3 = H1 * B; where B = (8% to 14%). After the current collector 1 is completely coated with the active material layer 2, a laser cleaning device thins the active material layer 2. The thinning thickness is set at a gradient of 8%, 10%, 12%, 14%, etc., of the rolled thickness of the cell electrode structure to form a thinned area, which is then striped to obtain the cell electrode structure. This structure can achieve a greater CB value in the thinned area than in the unthinned area, thereby better improving the lithium deposition phenomenon. When the thickness H3 of the second recess 32 is too large, the CB value will be too large; this will cause the oxidation state of the electrode to increase, increasing safety risks. When the thickness H3 of the second recess 32 is too small, the effect of improving lithium deposition is not achieved.

[0046] Among them, Figure 1 and 2 As shown, the tab 5 is welded to the current collector 1; and a protective layer 51 is further provided in the tab groove 4; the protective layer 51 is connected to the tab 5; and the projection of the protective layer 51 toward the current collector 1 covers the portion of the tab groove 4 where the tab 5 is located. The protective layer 51 is an adhesive. In other words, in order to ensure the assembly stability and comprehensiveness of the tab 5, a protective layer 51 with a larger coverage area is used to protect the tab 5, thereby improving the safety and stability of use. Figure 4 As shown, the relationship between the length D2 of the protective layer 51 and the length D1 of the tab 5 satisfies: D2-D1≥1mm.

[0047] The present invention also provides a battery cell, such as Figure 6 As shown, the battery cell includes a first electrode 100 and a second electrode 200 with opposite polarities, and a diaphragm 300 disposed between the first electrode 100 and the second electrode 200; at least one of the first electrode 100 and the second electrode 200 is a battery cell electrode structure; the specific structure of the battery cell electrode structure refers to the above embodiment. Since at least one of the first electrode 100 and the second electrode 200 adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the first electrode 100 is a cathode piece, and the second electrode 200 is an anode piece; or the first electrode 100 is an anode piece, and the second electrode 200 is a cathode piece.

[0048] Specifically, in some embodiments, Figure 6 As shown, the total thickness T of the bare cell and the width K of the thinning recess corresponding to the outermost winding satisfy the relationship: π / 3≤K / T≤2π / 3, where T satisfies: 2≤T≤20mm;

[0049] The width of the thinning recess corresponding to n-1 windings satisfies K-1*(2S+A+C);

[0050] The width of the thinning recess corresponding to n-2 circles satisfies K-2*(2S+A+C);

[0051] The width of the thinning recess corresponding to n turns satisfies Kn*(2S+A+C);

[0052] Among them, the total thickness of the bare battery cell is T; the width of the thinning recess corresponding to the outermost winding is K; the total thickness of the first pole piece after winding is C; the total thickness of the second pole piece after winding is A; the total thickness of the diaphragm after winding is S and the number of winding turns is n.

[0053] That is to say, when lithium deposition occurs at the corners of the electrode in the finished battery cell, specifically at the edges or both the corners and edges, laser cleaning equipment can be used to perform laser cleaning on the electrode where lithium deposition occurs according to the corresponding parameters, thereby improving the lithium deposition problem of the battery cell and enhancing battery safety.

[0054] Example 1

[0055] Laser cleaning equipment is used to thin the cathode sheet to form a thinning depression 3; the thinning thickness of the thinning depression 3 is set according to 8% of the rolled thickness of the battery cell electrode structure, and then the corresponding cathode sheet is obtained after stripping.

[0056] The lithium-ion battery containing the cathode sheet was then placed in a 25°C constant temperature chamber for 10 minutes. The battery was then charged at a constant current of 2.8C to a voltage of 4.50V. The battery was then charged at a constant voltage of 4.50V to a current of 0.05C. The battery was then discharged at a constant current of 1.0C to a voltage of 3.0V. This constituted one charge-discharge cycle. This cycle was repeated, and the battery was disassembled to observe the lithium deposition window interface after 20 cycles.

[0057] Example 2

[0058] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 10% of the rolled thickness of the battery cell electrode structure.

[0059] Example 3

[0060] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 12% of the rolled thickness of the battery cell electrode structure.

[0061] Example 4

[0062] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 14% of the rolled thickness of the battery cell electrode structure.

[0063] Example 5

[0064] The difference from Example 2 is that the total thickness T of the bare cell is 5 mm, and the width K of the thinning recess corresponding to the outermost winding is 3.33π mm; that is, K / T=2 / 3π.

[0065] Example 6

[0066] The difference from Example 2 is that the total thickness T of the bare cell is 5 mm, and the width K of the thinning recess corresponding to the outermost winding is 1.67πmm; that is, K / T=π / 3.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 4% of the rolled thickness of the battery cell electrode structure.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 6% of the rolled thickness of the battery cell electrode structure.

[0071] Comparative Example 3

[0072] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 16% of the rolled thickness of the battery cell electrode structure.

[0073] Comparative Example 4

[0074] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 16% of the rolled thickness of the battery cell electrode structure.

[0075] Comparative Example 5

[0076] The difference from Example 1 is that the thinning thickness of the thinning recess 3 is set to 18% of the rolled thickness of the battery cell electrode structure.

[0077] Table 1 - Performance parameters of all examples and comparative examples

[0078]

[0079] Among them, the lithium plating levels are marked as A<B<C from mild to severe.

[0080] As can be seen in the table:

[0081] 1. When the thickness of the thinning depression 3 is controlled to be 10% of the rolled thickness of the cell electrode structure, the electrode corner can be effectively improved to prevent lithium deposition. In addition, the width of the thinning depression and the thickness of the cell should be controlled within a reasonable range:

[0082] When K / T=2 / 3π, as in Example 5, the core thickness is consistent, and the width K of the thinned recess corresponding to the outermost winding is T*2π / 3. The overall corner area is relatively loose, and more electrolyte is stored, but the lithium ion transmission path becomes longer. Therefore, the lithium plating improvement effect is worse than that of the embodiment with K=π / 2*T.

[0083] When K / T=π / 3, as in Example 6, when the width K of the thinned recess corresponding to the outermost winding is T*1π / 3, the overall corner area is wound more tightly. Although the lithium ion transmission path becomes shorter, the electrolyte storage in the local area is less. As the cycle progresses, the electrolyte consumption increases, which in turn causes the lithium precipitation to worsen.

[0084] Therefore, it is preferred that K / T = π / 2, as in Example 2. At this time, the bare cell winding yield is optimal and the lithium plating improvement effect is best.

[0085] 2. When the edges or corners of the cathode sheet are not thinned, the lithium ions are completely released at a 2.8C charging rate, resulting in severe lithium deposition in the local area of the electrode sheet, which in turn affects performance.

[0086] 3. When the thinning value is too high, the CB value is too large, the local positive electrode oxidation state increases, resulting in purple spots on the interface, which in turn aggravates lithium deposition;

[0087] 4. According to the corresponding parameters (as shown in Example 5, T = 5mm, K = 2.5πmm, at this time K / T = π / 2), laser cleaning equipment is used to laser clean the lithium deposition area of the electrode to improve the lithium deposition problem of the battery cell and improve battery safety.

[0088] Therefore, the present invention designs a pole piece with better components by combining the thinning thickness of the thinning area and the coating width thereof, thereby improving the local lithium deposition of the lithium-ion battery and achieving the effect of improving the battery safety.

[0089] The present invention also provides a battery, which includes a battery cell. The specific structure of the battery cell refers to the above embodiments. Since the battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0090] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0091] Based on the disclosure and teachings of the above description, those skilled in the art will be able to make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on the present invention fall within the scope of protection of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience only and do not constitute any limitation on the present invention.

Claims

1. A battery cell electrode structure, characterized in that: It includes a current collector and an active material layer connected to at least one surface of the current collector; the active material layer is provided with at least one thinned depression along the width direction of the surface; the active material layer is also provided with a tab groove; the tab groove is arranged to penetrate along the thickness direction of the active material layer; the tab groove is used to install the tab; and the bottom of the tab groove extends to the surface of the current collector.

2. The battery cell electrode structure according to claim 1, characterized in that: The thinning recess includes at least one first recess; the first recess is arranged parallel to the width direction of the active material layer; and the first recess is arranged throughout the width direction of the active material layer.

3. The battery cell electrode structure according to claim 2, characterized in that: When the battery cell electrode structure is in a wound state, the first recess is arranged at a turning position; and / or, at most a portion of the first recess is arranged at a straight position.

4. The battery cell electrode structure according to claim 2 or 3, characterized in that: The relationship between the thickness H2 of the first recess and the thickness H1 of the cell electrode structure satisfies: H2=H1*A; wherein A=8% to 14%.

5. The battery cell electrode structure according to claim 1 or 2, characterized in that: The thinning recess further includes at least one second recess; the second recess is provided on at least one side in the width direction of the active material layer; and the second recess abuts against an edge in the width direction of the active material layer.

6. The battery cell electrode structure according to claim 5, characterized in that: The value range of the width L1 of the second recess satisfies: L1 = 5 to 10 mm; And / or, the relationship between the thickness H3 of the second recess and the thickness H1 of the battery cell electrode structure satisfies: H3=H1*B; wherein B=8% to 14%.

7. The battery cell electrode structure according to claim 1, characterized in that: A protective layer is further provided in the tab groove; the protective layer is connected to the tab; and the projection of the protective layer toward the current collector covers the portion of the tab groove where the tab is located; The relationship between the length of the protective layer and the length D1 of the tab satisfies the following equation: D2-D1≥1mm.

8. A battery cell, characterized in that: It includes a first pole piece and a second pole piece with opposite polarities and a diaphragm arranged between the first pole piece and the second pole piece; the first pole piece, the second pole piece and the diaphragm are wound to form a bare battery cell; at least one of the first pole piece and the second pole piece is the battery cell pole piece structure described in any one of claims 1 to 7 above.

9. The battery cell according to claim 8, characterized in that: The total thickness T of the bare cell and the width K of the thinning recess corresponding to the outermost winding satisfy the relationship: π / 3≤K / T≤2π / 3, where T satisfies: 2≤T≤20mm; The width of the thinning recess corresponding to n-1 windings satisfies K-1*(2S+A+C); The width of the thinning recess corresponding to n-2 circles satisfies K-2*(2S+A+C); The width of the thinning recess corresponding to n turns satisfies Kn*(2S+A+C); Among them, the total thickness of the bare battery cell is T; the width of the thinning recess corresponding to the outermost winding is K; the total thickness of the first pole piece after winding is C; the total thickness of the second pole piece after winding is A; the total thickness of the diaphragm after winding is S and the number of winding turns is n.

10. A battery, characterized in that: Comprising the battery cell according to claim 8 or 9.

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