Battery cell structure and battery
By designing pleated anode sheets and embossed cathode segments in the cell structure, the problem of anode sheet breakage caused by high silicon materials is solved, improving the reliability and capacity of the battery. At the same time, lithium-ion diffusion is optimized, avoiding lithium plating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG LIWINON ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-06-24
- Publication Date
- 2026-07-14
Smart Images
Figure CN224501901U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a cell structure and a battery. Background Technology
[0002] As market demand for consumer batteries continues to increase, the requirements for battery capacity are also rising. Battery active materials are shifting from traditional graphite to silicon, which boasts high specific capacity, leading to a significant increase in battery capacity. However, silicon, when used as a battery active material, exhibits an expansion rate exceeding 300%, placing higher demands on battery reliability. With an increasing proportion of silicon in the graphite system, the battery expansion rate continues to rise, and due to internal stress within the core, the risk of anode sheet breakage increases continuously.
[0003] The current solution for electrode breakage in high-silicon systems is to increase the thickness of the anode foil, which can effectively improve the tensile strength and elongation of the foil. However, increasing the foil thickness will worsen the battery capacity, offsetting the capacity improvement brought by high silicon. Utility Model Content
[0004] The purpose of this invention is to provide a cell structure to solve the problem of breakage of the core electrode sheet after expansion in the prior art; this invention also provides a battery using this cell structure.
[0005] To achieve the above objectives, this utility model provides a battery cell structure, including an anode sheet, a cathode sheet, and a separator, wherein the separator is stacked between the anode sheet and the cathode sheet, and the anode sheet, the cathode sheet, and the separator are wound into a core, wherein the core has a straight portion and a corner portion;
[0006] Along the length of the anode sheet, the anode sheet includes a telescopic section with pleats;
[0007] The cathode sheet includes a plurality of embossed segments spaced apart along the length of the cathode sheet. Each embossed segment includes a plurality of embossed units. The embossed segments are located at the corners. Along the length of the cathode sheet, the dimension of each embossed segment is L, satisfying the following:
[0008] L = (D0 + N * ΔT) * π / 2;
[0009] ΔT=D 阴 +D 阳 +2*D 膜 ;
[0010] Where D0 is the thickness of the core at the first fold corner, N is the number of layers in the core, ΔT is the cumulative thickness difference at each corner, and D 阴 D represents the thickness of the cathode sheet. 阳D represents the thickness of the anode sheet, and Dmembrane represents the thickness of the diaphragm.
[0011] Optionally, each of the embossing units is spaced apart along the length of the cathode sheet, and the gap between two adjacent embossing units is S, where 100μm < S < 200μm.
[0012] Optionally, the embossing depth of each embossing unit is H, where 80 μm < H < 120 μm.
[0013] Optionally, the embossing directions of two adjacent embossing units are opposite.
[0014] Optionally, the diaphragm includes a base membrane, a ceramic layer, and a particulate adhesive layer. The ceramic layer is disposed on one side of the base membrane in the thickness direction. The particulate adhesive layer is disposed on both the side of the base membrane away from the ceramic layer and the side of the ceramic layer away from the base membrane. The particulate adhesive layer is used to support the cathode plate and the anode plate, so that there are gaps between the diaphragm and the cathode plate and between the diaphragm and the anode plate.
[0015] Optionally, the corner portion shrinks inward along the width direction of the core, the size of the corner portion is R1 along the thickness direction of the core, and the size of the corner portion is R2 along the width direction of the core, where R2 < R1 / 2.
[0016] Optionally, 0.05mm < (R1 / 2) - R2 < 0.3mm.
[0017] Optionally, the particulate adhesive layer includes a particulate polymer and an adhesive layer bonding the particulate polymer, wherein the particle size of the particulate polymer is M, 5μm < M < 7μm.
[0018] Optionally, the folds are either wavy or V-shaped.
[0019] This utility model also provides a battery, including an aluminum-plastic film and a cell structure disposed within the aluminum-plastic film, wherein the cell structure is the cell structure described in any of the above technical solutions.
[0020] Compared with the prior art, the beneficial effects of this utility model embodiment of the cell structure and battery are as follows: the anode sheet has folds in the expansion section. During the expansion process of the cell structure, the foil of the anode sheet is stretched along the length direction, which can first stretch and unfold the folds in the expansion section, effectively increasing the fatigue resistance of the anode sheet and reducing the occurrence of sheet breakage; at the same time, an embossed section is provided on the cathode sheet at the corner position. The length of the embossed section corresponds to the size of the outermost circle of the corner, ensuring that each fold of the cathode sheet at the corner has an embossed section. The embossed section can make the anode sheet and the cathode sheet have a gap, providing space for the expansion of the anode sheet, reducing the risk of the outermost anode sheet breaking due to the accumulation of internal stress in the core, and avoiding the anode sheet breaking after expansion. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the battery cell structure of this utility model;
[0022] Figure 2 yes Figure 1 A schematic diagram of the anode sheet structure of the battery cell;
[0023] Figure 3 yes Figure 1 A schematic diagram of the cathode sheet structure of the battery cell;
[0024] Figure 4 yes Figure 1 A schematic diagram of the separator structure of the battery cell.
[0025] In the figure, 1 is the anode plate, 11 is the expansion section, 12 is the pleat, 2 is the cathode plate, 21 is the embossed section, 22 is the embossed unit, 3 is the diaphragm, 31 is the base film, 32 is the ceramic layer, 33 is the particulate adhesive layer, 331 is the particulate polymer, 332 is the adhesive layer, 4 is the core, 41 is the straight section, and 42 is the corner section. Detailed Implementation
[0026] The specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit its scope.
[0027] A preferred embodiment of the battery cell structure of this utility model is as follows: Figures 1 to 4 As shown, the battery cell structure includes an anode plate 1, a cathode plate 2, and a separator 3. The separator 3 is stacked between the anode plate 1 and the cathode plate 2. The anode plate 1, the cathode plate 2, and the separator 3 are wound into a core 4. The separator 3 is used to insulate and isolate the anode plate 1 and the cathode plate 2, preventing them from directly contacting and short-circuiting. The core 4 has a straight portion 41 and a corner portion 42. Along the width direction of the core 4, there are two corner portions 42, located at both ends of the straight portion 41.
[0028] Along the length of the anode sheet 1, the anode sheet 1 includes a telescopic section 11, and the anode sheet 1 has folds 12 in the telescopic section 11, with the folds 12 stacked along the length of the anode sheet 1. When the cell structure expands, in the early stage of cycling, the folds 12 of the anode sheet 1 can be stretched and unfolded along the length of the anode sheet 1. After cycling, it is expected that the folds 12 of the telescopic section 11 will be fully unfolded, and the anode sheet 1 will be stretched and extended by the tensile strength and elongation of the foil itself, effectively increasing the fatigue resistance of the anode sheet 1. In addition, the folds 12 can also create gaps in the thickness direction inside the core 4. When the cell structure expands in the thickness direction, the anode sheet 1 is squeezed in the thickness direction, causing the anode sheet 1 to be stretched in its length direction.
[0029] The cathode sheet 2 includes multiple embossed sections 21, which are spaced apart along the length of the cathode sheet 2. The embossed sections 21 are located at the corners 42 of the core 4, that is, the embossed sections 21 on the cathode sheet 2 correspond to the corners 42 of the core 4. Each embossed section 21 includes multiple embossed units 22, which are spaced apart. The embossed units 22 create a concave-convex structure on the cathode sheet 2 in the embossed section 21, which significantly improves the gap of the core 4 at the corners 42, effectively increases the liquid retention capacity of the corners 42, and provides a buffer space for the expansion of the anode sheet 1, reducing sheet breakage.
[0030] Along the length of the cathode plate 2, the dimensions of each embossed section 21 are L, satisfying: L=(D0+N*ΔT)*π / 2; ΔT=D 阴 +D 阳 +2*D 膜 Wherein, D0 is the thickness of the core 4 at the first fold corner, N is the number of layers of the core 4, ΔT is the cumulative thickness difference of each layer at the corner 42, D_cathode is the thickness of the cathode sheet 2, D_anode is the thickness of the anode sheet 1, and D_film is the thickness of the diaphragm 3.
[0031] When the core 4 is wound, the first fold of the core 4 will be pre-wound into the diaphragm 3, and some of the cathode sheet 2 and anode sheet 1 will be inserted into the sheet. Therefore, the thickness D0 of the first fold corner of the core 4 will be greater than ΔT. Therefore, calculating D0 separately when calculating the thickness of the outermost fold of the core 4 can ensure the accuracy of the calculation results.
[0032] For each additional fold of the core 4, the cumulative thickness difference ΔT = Dcathode + Danode + 2 * Dfilm, which increases the thickness of two layers of diaphragm 3, one layer of cathode sheet 2, and one layer of anode sheet 1. The corner portion 42 is usually semi-circular, and (D0 + N * ΔT) is the diameter of the corner portion 42. The outermost dimension of the corner portion 42 can be obtained using the above formula. The outermost dimension of the corner portion 42 is the maximum dimension of each fold. Each embossed section 21 is based on the outermost dimension of the corner portion 42, ensuring that the cathode sheet 2 of each fold of the corner portion 42 has an embossed section 21.
[0033] The anode sheet 1 of this battery cell structure has pleats 12 in the expansion section 11. During the expansion process, the foil of the anode sheet 1 is stretched along the length direction, which can first stretch and unfold the pleats 12 in the expansion section 11, effectively increasing the fatigue resistance of the anode sheet 1 and reducing the occurrence of breakage. At the same time, an embossed section 21 is provided on the cathode sheet 2 at the corner 42. The length of the embossed section 21 corresponds to the size of the outermost ring of the corner 42, ensuring that each fold of the cathode sheet 2 at the corner 42 has an embossed section 21. The embossed section 21 can create a gap between the anode sheet 1 and the cathode sheet 2, providing space for the expansion of the anode sheet 1, reducing the risk of breakage of the outermost anode sheet 1 caused by the accumulation of internal stress in the core 4, and avoiding breakage of the anode sheet 1 after expansion.
[0034] In some embodiments, each embossing unit 22 is arranged at intervals along the length direction of the cathode sheet 2, and the gap between two adjacent embossing units 22 is S, where 100μm < S < 200μm.
[0035] When the gap S between the embossing units 22 is less than 100 μm, the stress per unit area of the cathode sheet 2 increases, the strength of the cathode sheet 2 decreases, and it is more likely to break. When the gap S between the embossing units 22 is greater than 200 μm, the support of the cathode sheet 2 at the corner 42 becomes smaller, but the gap between the cathode sheet 2 and the diaphragm 3 becomes smaller, which cannot provide sufficient expansion gap.
[0036] In some embodiments, the embossing depth of each embossing unit 22 is H, where 80 μm < H < 120 μm.
[0037] When the embossing depth H of the pressure ring unit is less than 80 μm, the gap at the support of the embossing unit 22 is small and cannot provide sufficient expansion gap; when the embossing depth H of the pressure ring unit is greater than 120 μm, the cathode sheet 2 will be damaged in the embossing section 21.
[0038] In some embodiments, the embossing directions of two adjacent embossing units 22 are opposite.
[0039] The embossing directions of two adjacent embossing units 22 are opposite. The embossing section 21 is double-sided embossed. Compared with single-sided embossing, the embossing section 21 can provide twice the expansion gap, effectively improving the liquid retention capacity of the corner 42, providing buffer space for the expansion of the anode sheet 1 in the thickness direction, and reducing electrode breakage.
[0040] In some embodiments, the diaphragm 3 includes a base membrane 31, a ceramic layer 32, and a particulate adhesive layer 33. The ceramic layer 32 is disposed on one side of the base membrane 31 in the thickness direction. The particulate adhesive layer 33 is disposed on both the side of the base membrane 31 away from the ceramic layer 32 and the side of the ceramic layer 32 away from the base membrane 31. The particulate adhesive layer 33 is used to support the cathode plate 2 and the anode plate 1, so that there are gaps between the diaphragm 3 and the cathode plate 2 and between the diaphragm 3 and the anode plate 1.
[0041] On the opposite sides of the ceramic layer 32 and the base film 31, the separator 3 has particulate adhesive layers 33. After the separator 3 is wound, the particulate polymer 331 in the particulate adhesive layer 33 can effectively support the cathode plate 2 and the anode plate 1, so that there are gaps between the separator 3 and the anode plate 1, and between the separator 3 and the cathode plate 2, which can increase the liquid retention capacity and provide expansion buffer space. By optimizing the structure of the anode plate 1, the cathode plate 2 and the separator 3, the synergistic effect of the three can solve the problems of wafer breakage and lithium plating at corners in high-silicon systems.
[0042] In some embodiments, the corner portion 42 is tapered inward along the width direction of the core 4, and the size of the corner portion 42 is R1 along the thickness direction of the core 4, and the size of the corner portion 42 is R2 along the width direction of the core 4, where R2 < R1 / 2.
[0043] Gaps will be generated at the corner 42 of the core 4 in the expansion section 11 of the anode sheet 1, the embossed section 21 of the cathode sheet 2, and the particulate adhesive layer 33 of the diaphragm 3. This will cause the gaps to accumulate at the corner 42 of the core 4, which will easily lead to weak adhesion of the electrode components, disrupt the lithium ion diffusion path, and cause the diffusion distance to increase, resulting in the corner lithium plating phenomenon.
[0044] The corner portion 42 contracts inward along the width direction of the core 4, which can adjust the shape of the core 4 at the corner portion 42, flatten some of the gaps in the corner portion 42, and reduce the lithium plating phenomenon at the corner caused by excessive gaps. In this embodiment, after the core 4 is wound and formed, it is pressed in the width direction, that is, the core 4 is heated and squeezed in the width direction to compress the corner portion 42 of the core 4 inward along the width direction, turning the large radius R-angle into a flattened R-angle. After the R-angle is squeezed, the cumulative stress between each fold of the core 4 can be reduced, reducing electrode breakage.
[0045] In some embodiments, 0.05mm < (R1 / 2) - R2 < 0.3mm.
[0046] If the corner portion 42 is squeezed too little along its width, the difference between R1 / 2 and R2 of the corner portion 42 will be too small, resulting in an excessively large gap in the corner portion 42 and exacerbating electrode breakage. If the squeeze is too large, the difference between R1 / 2 and R2 of the corner portion 42 will be too large, and the corner portion 42 will squeeze the electrolyte, making it easy for the electrolyte in the corner portion 42 to be squeezed out, which will worsen the lithium plating phenomenon.
[0047] In some embodiments, the particulate adhesive layer 33 includes a particulate polymer 331 and an adhesive layer 332 for bonding the particulate polymer 331, wherein the particle size of the particulate polymer 331 is M, and 5μm < M < 7μm.
[0048] The particulate polymer 331 supports the cathode plate 2 and the anode plate 1, ensuring gaps on both sides of the separator 3. The adhesive layer 332 serves to bond and fix the separator 3, ensuring good adhesion between the separator 3 and the cathode plate 2, and between the separator 3 and the anode plate 1. It can also bond and fix the particulate polymer 331 to both sides of the separator 3. In this embodiment, the mass fraction ratio of the adhesive layer 332 to the particulate polymer 331 is between 6:4 and 7:3, ensuring that the gap is within a suitable range. If the mass fraction of the adhesive layer 332 is too small, it will result in poor adhesion at the corner 42 and an excessively large gap, leading to a large lithium-ion diffusion distance. If the mass fraction of the adhesive layer 332 is too large, it will result in an excessively small gap, causing the expansion gap to fail.
[0049] When the particle size M of the particulate polymer 331 is less than 5 μm, the gaps generated by the particulate adhesive layer 33 are small and insufficient to provide the required expansion gaps; when the particle size M of the particulate polymer 331 is greater than 7 μm, the gaps at the corners 42 are too large, which will affect ion transfer and increase the lithium plating phenomenon at the corners 42.
[0050] In some embodiments, the pleats 12 are either wavy or V-shaped.
[0051] Wavy or V-shaped pleats 12 are commonly used shapes and are simple to process. Preferably, the pleats 12 are wavy, which can reduce the internal stress of the anode sheet 1. In this embodiment, the anode sheet 1 is wavy throughout its length, that is, the entire anode sheet 1 is a telescopic section 11. Before winding, the anode sheet 1 is rolled by a longitudinally wavy concave-convex roller to obtain the wavy pleats 12. In other embodiments, the telescopic section 11 may only be provided at a portion of the length of the anode sheet 1.
[0052] This utility model also provides a battery, including an aluminum-plastic film and a cell structure disposed within the aluminum-plastic film. The specific structure of the cell structure is the same as that of the cell structure described in any of the above embodiments, and will not be repeated here.
[0053] In summary, this utility model embodiment provides a cell structure and battery, wherein the anode sheet has folds in the expansion section. During the expansion process of the cell structure, the foil of the anode sheet is stretched along the length direction, which can first stretch and unfold the folds in the expansion section, effectively increasing the fatigue resistance of the anode sheet and reducing the occurrence of sheet breakage. At the same time, an embossed section is provided on the cathode sheet at the corner position. The length of the embossed section corresponds to the size of the outermost circle of the corner, ensuring that each fold of the cathode sheet at the corner has an embossed section. The embossed section can create a gap between the anode sheet and the cathode sheet, providing space for the expansion of the anode sheet, reducing the risk of the outermost anode sheet breaking due to the accumulation of internal stress in the core, and avoiding the anode sheet breaking after expansion.
[0054] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.
Claims
1. A battery cell structure, characterized in that, It includes an anode plate (1), a cathode plate (2) and a diaphragm (3), wherein the diaphragm (3) is stacked between the anode plate (1) and the cathode plate (2), and the anode plate (1), the cathode plate (2) and the diaphragm (3) are wound into a core (4), wherein the core (4) has a straight portion (41) and a corner portion (42); Along the length direction of the anode plate (1), the anode plate (1) includes a telescopic section (11) with pleats (12); The cathode sheet (2) includes a plurality of embossed segments (21) spaced apart along the length of the cathode sheet (2). Each embossed segment (21) includes a plurality of embossed units (22). The embossed segment (21) is located at the corner (42). Along the length of the cathode sheet (2), the size of each embossed segment (21) is L, satisfying: L = (D0 + N * ΔT) * π / 2; ΔT=D 阴 +D 阳 +2*D 膜 ; Where D0 is the thickness of the core (4) at the first fold corner, N is the number of layers of the core (4), ΔT is the cumulative thickness difference of each corner (42), and D 阴 D is the thickness of the cathode sheet (2). 阳 D represents the thickness of the anode sheet (1). 膜 The thickness of the diaphragm (3) is given.
2. The cell structure according to claim 1, characterized in that, Each of the embossing units (22) is arranged at intervals along the length of the cathode sheet (2), and the gap between two adjacent embossing units (22) is S, where 100μm < S < 200μm.
3. The cell structure according to claim 1, characterized in that, The embossing depth of each embossing unit (22) is H, where 80 μm < H < 120 μm.
4. The cell structure according to claim 1, characterized in that, The embossing directions of two adjacent embossing units (22) are opposite.
5. The cell structure according to any one of claims 1-4, characterized in that, The diaphragm (3) includes a base film (31), a ceramic layer (32), and a particulate adhesive layer (33). The ceramic layer (32) is disposed on one side of the base film (31) in the thickness direction. The particulate adhesive layer (33) is disposed on both the side of the base film (31) away from the ceramic layer (32) and the side of the ceramic layer (32) away from the base film (31). The particulate adhesive layer (33) is used to support the cathode plate (2) and the anode plate (1) so that there are gaps between the diaphragm (3) and the cathode plate (2) and between the diaphragm (3) and the anode plate (1).
6. The cell structure according to claim 5, characterized in that, The corner portion (42) contracts inward along the width direction of the core (4), and the size of the corner portion (42) is R1 along the thickness direction of the core (4). The size of the corner portion (42) is R2 along the width direction of the core (4), and R2 < R1 / 2.
7. The cell structure according to claim 6, characterized in that, 0.05mm < (R1 / 2) - R2 < 0.3mm.
8. The cell structure according to claim 5, characterized in that, The particulate adhesive layer (33) includes a particulate polymer (331) and an adhesive layer (332) that binds the particulate polymer (331). The particle size of the particulate polymer (331) is M, where 5 μm < M < 7 μm.
9. The cell structure according to any one of claims 1-4, characterized in that, The folds (12) are either wavy or V-shaped.
10. A battery, characterized in that, It includes an aluminum-plastic film and a battery cell structure disposed within the aluminum-plastic film, wherein the battery cell structure is the battery cell structure according to any one of claims 1-9.