Battery cell structure

Abstract

The utility model discloses a battery cell structure. The battery cell structure comprises a first pole piece, a first diaphragm and a plurality of supporting particles, the first pole piece is provided with a first bending area, the first diaphragm is attached to the first pole piece, and the first diaphragm is provided with a second bending area corresponding to the first bending area. The second bending area is coated with the multiple supporting particles, and gaps among the multiple supporting particles are used for containing electrolyte. Wherein the surface, facing the first diaphragm, of the first bending area is sunken to form a plurality of first grooves, and the first grooves are all used for containing electrolyte. Through the design of the supporting particles and the first grooves, the storage space of the electrolyte is increased at the bending part of the battery cell structure, so that the electrolyte retention effect at the corner of the battery cell is improved. Therefore, the battery cell structure provided by the utility model can provide enough electrolyte at the bending part for migration of the lithium ions, and the lithium ions are effectively separated from the positive electrode and embedded into the negative electrode, so that the lithium separation phenomenon is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, and in particular to a battery core structure. Background Art

[0002] With the advancement of technology, lithium batteries have become an indispensable power source for modern electronic products. Their performance directly affects the user experience and battery life of these products. The core component of a lithium battery is the cell, and its structural design and manufacturing process play a crucial role in the battery's overall performance.

[0003] Currently, the widely used soft-pack lithium-ion battery cells are typically manufactured using a winding process that stacks positive and negative electrodes and a separator. This structure experiences significant expansion and contraction during battery cycling, as lithium ions are inserted and extracted between the positive and negative electrodes. However, this expansion and contraction is particularly pronounced at the corners of the cell, where structural characteristics lead to stress concentrations.

[0004] In related technologies, as batteries are continuously cycled, the gaps at the corners gradually decrease due to the repeated expansion and contraction of the electrode plates. This change causes the electrolyte to be gradually squeezed out of this area, significantly reducing the electrolyte content at the corners. This reduction in electrolyte directly affects the efficiency of lithium ion transmission between the positive and negative electrodes, leading to lithium plating. Lithium plating not only reduces the battery's energy density but can also cause internal short circuits and, in severe cases, even lead to safety accidents. Utility Model Content

[0005] The main purpose of this utility model is to propose a battery cell structure, which improves the ability of retaining electrolyte at the corners of the battery cell so that lithium ions can smoothly migrate to the negative electrode through the electrolyte, thereby effectively improving the problem of lithium deposition at the corners of the battery cell structure.

[0006] To achieve the above objectives, some embodiments of the present invention provide a battery cell structure, including:

[0007] A first pole piece having a first bending region;

[0008] a first diaphragm, attached to the first pole piece, the first diaphragm having a second bending area corresponding to the first bending area;

[0009] A plurality of support particles are coated on the second bending region, and gaps between the plurality of support particles are used to accommodate electrolyte;

[0010] The first bending region is recessed toward the surface of the first diaphragm to form a plurality of first grooves, and the plurality of first grooves are all used to accommodate electrolyte.

[0011] In some embodiments, the range of the aperture R1 of the first groove is: 50 μm≤R1≤100 μm.

[0012] In some embodiments, the depth h1 of the first groove and the thickness H1 of the first pole piece satisfy the relationship: 0.2≤h1 / H1≤0.3.

[0013] In some embodiments, the plurality of first grooves are spaced apart.

[0014] In some embodiments, the distance L1 between two adjacent first grooves satisfies: 1.2 mm ≤ L1 ≤ 1.8 mm.

[0015] In some embodiments, along the extension direction of the first pole piece, the second bending region covers the first bending region.

[0016] In some embodiments, the particle size D1 of the support particles is in the range of 5 μm ≤ D1 ≤ 8 μm.

[0017] In some embodiments, the support particles are elastic.

[0018] In some embodiments, the battery cell structure also includes a second electrode plate, which is located on the side of the first diaphragm away from the first electrode plate. The second electrode plate has a third bending area corresponding to the first bending area. The third bending area is recessed toward the surface of the first diaphragm to form multiple second grooves, and the multiple second grooves are all used to accommodate electrolyte.

[0019] In some embodiments, the first electrode is a negative electrode, and the first electrode includes a long fabric area and a short fabric area that are relatively arranged. The surface density of the long fabric area is 0.5% to 1% greater than the surface density of the short fabric area.

[0020] According to the above embodiments, the beneficial effects of the present invention are:

[0021] The battery cell structure of the present application includes a first electrode, a first diaphragm and a plurality of support particles. The first electrode has a first bending area, the first diaphragm is attached to the first electrode, and the first diaphragm has a second bending area corresponding to the first bending area. A plurality of support particles are coated in the second bending area, and the gaps between these support particles are designed to accommodate electrolyte. A plurality of first grooves are formed on the surface of the first bending area facing the first diaphragm, and these first grooves are also used to accommodate electrolyte. The design of the support particles and the first grooves increases the storage space of the electrolyte at the bend of the battery cell structure of the present application, thereby improving the liquid retention effect at the corner of the battery cell. Therefore, the battery cell structure of the present application can provide sufficient electrolyte for lithium ion migration at the bend, and the lithium ions are effectively removed from the positive electrode and embedded in the negative electrode, thereby preventing the occurrence of lithium plating.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0024] Figure 1 This is a schematic structural diagram of a battery cell structure in one embodiment of the present utility model;

[0025] Figure 2 This is a schematic structural diagram of a first pole piece and a second pole piece in one embodiment of the present invention;

[0026] Figure 3 This is a schematic structural diagram of the first diaphragm-coated support particles in one embodiment of the present invention;

[0027] Figure 4 This is a schematic structural diagram of the first pole piece in one embodiment of the present invention.

[0028] Description of Figure Numbers:

[0029] a first pole piece 100;

[0030] First bending area 110; corner material area 111; first groove 1111;

[0031] long fabric area 120;

[0032] short fabric area 130;

[0033] a first diaphragm 200;

[0034] a second bending region 210;

[0035] a second pole piece 300;

[0036] A third bending area 310; a second groove 311;

[0037] Support particles 400.

[0038] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0041] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or", "and / or" or "and / or" appear in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] In related technologies, as batteries are continuously cycled, the gaps at the corners gradually decrease due to the repeated expansion and contraction of the electrode plates. This change causes the electrolyte to be gradually squeezed out of this area, significantly reducing the electrolyte content at the corners. This reduction in electrolyte directly affects the efficiency of lithium ion transmission between the positive and negative electrodes, leading to lithium plating. Lithium plating not only reduces the battery's energy density but can also cause internal short circuits and, in severe cases, even lead to safety accidents.

[0043] Reference below Figures 1 to 4 To describe the battery cell structure according to an embodiment of the present invention.

[0044] Reference Figures 1 to 3In some embodiments, the battery cell structure of the present application includes a first electrode 100, a first diaphragm 200 and a plurality of support particles 400. The first electrode 100 has a first bending area 110, the first diaphragm 200 is attached to the first electrode 100, and the first diaphragm 200 has a second bending area 210 corresponding to the first bending area 110. A plurality of support particles 400 are coated in the second bending area 210, and the gaps between these support particles 400 are designed to accommodate electrolyte. A plurality of first grooves 1111 are formed on the surface of the first bending area 110 facing the first diaphragm 200, and these first grooves 1111 are also used to accommodate electrolyte. The design of the support particles 400 and the first grooves 1111 increases the storage space of the electrolyte at the bend of the battery cell structure of the present application, thereby improving the liquid retention effect at the corners of the battery cell. Therefore, the battery cell structure of the present application can provide sufficient electrolyte for lithium ion migration at the bend, and lithium ions are effectively released from the positive electrode and embedded in the negative electrode, thereby preventing the occurrence of lithium plating.

[0045] It is understandable that in some embodiments, in order to further optimize the performance of the battery cell, the aperture R1 of the first groove 1111 is set within a specific range. Specifically, the size of the aperture R1 determines the storage capacity of the electrolyte and the efficiency of lithium ion migration. If R1 is too small, it may limit the smooth migration of lithium ions; if R1 is too large, it may cause electrolyte loss. Therefore, reasonably controlling R1 between 50μm and 100μm can ensure that while ensuring sufficient electrolyte storage, lithium ions can also effectively migrate. This not only enhances the stability of the battery cell, but also improves the working efficiency of the battery cell.

[0046] Specifically, in some embodiments, the range of the aperture R1 of the first groove 1111 is set to 50μm≤R1≤100μm. For example, R1 can be 50μm, 60μm, 70μm, 80μm, 90μm, or 100μm. By limiting the aperture R1 of the first groove 1111 to this range, it can be ensured that the first groove 1111 can store sufficient electrolyte while allowing lithium ions to pass smoothly. Such an aperture size will neither hinder the migration path of lithium ions due to being too small, nor reduce the electrolyte retention capacity due to being too large, thereby achieving an ideal balance between electrolyte storage and lithium ion migration, thereby improving the overall performance of the battery cell.

[0047] Of course, it is understandable that, referring to Figure 2 In some embodiments, specifically, the first bending region 110 includes segmented corner material areas 111 , and the first grooves 1111 may be distributed in groups in the corner material areas 111 .

[0048] It is understood that in some embodiments, to further improve the reliability and consistency of the battery cell structure, the selection of aperture R1 also needs to take into account factors such as the material properties of the first electrode 100 and the physical properties of the electrolyte. For example, for different materials, the aperture size may need to be adjusted to accommodate different electrolyte viscosities and fluidities. In addition, the electrolyte retention capacity can be enhanced by changing the structural design around the aperture, such as increasing the roughness of the aperture edge and utilizing the capillary effect to increase the adsorption force of the electrolyte. These measures can help achieve better battery cell performance.

[0049] In some embodiments, the depth h1 of the first groove 1111 and the thickness H1 of the first pole piece 100 satisfy the relationship: 0.2 ≤ h1 / H1 ≤ 0.3. For example, the ratio h1 / H1 can be 0.2, 0.22, 0.24, 0.26, 0.28, or 0.3. The ratio between the depth h1 of the first groove 1111 and the thickness H1 of the first pole piece 100 determines the effective volume of the first groove 1111 and its electrolyte retention capacity. When the ratio h1 / H1 is too small, the volume of the first groove 1111 is insufficient, resulting in a decrease in electrolyte retention capacity. Conversely, if the ratio is too large, it may cause unnecessary damage to the first pole piece 100 or weaken its structural strength. Therefore, by controlling the ratio h1 / H1 between 0.2 and 0.3, the first groove 1111 is ensured to have sufficient space to store electrolyte without negatively impacting the structural integrity of the first pole piece 100. This design can significantly improve the electrolyte retention performance of the battery cell in the curved area, thereby optimizing the migration efficiency of lithium ions.

[0050] It is understood that in some embodiments, to achieve better electrolyte retention, the ratio h1 / H1 can be optimized by adjusting the hardness of the first pole piece 100 material or changing the geometry of the first groove 1111. For example, by selecting a material with moderate hardness, it is possible to form a first groove 1111 of appropriate depth through appropriate processing while maintaining the overall rigidity of the first pole piece 100. Furthermore, consideration can be given to introducing tiny protrusions at the bottom or sides of the first groove 1111 to enhance electrolyte adsorption and further improve electrolyte retention. These improvements contribute to improving the overall performance of the battery cell.

[0051] Reference Figure 2In some embodiments, multiple first grooves 1111 are distributed at intervals. By maintaining a certain distance between the first grooves 1111, the stability of the mechanical structure of the first pole piece 100 can be maintained while ensuring the electrolyte retention capacity. Multiple first grooves 1111 distributed at intervals can be evenly distributed throughout the first bending area 110, which can ensure that the entire first bending area 110 can effectively store electrolyte and avoid stress concentration problems caused by local over-density. This layout is not only conducive to the uniform distribution of the electrolyte, but also can enhance the deformation resistance of the first pole piece 100 and improve the service life of the battery cell.

[0052] It is understood that in some embodiments, in order to further optimize the layout of the first grooves 1111, the number and size of the first grooves 1111 can be adjusted. For example, while ensuring that the total volume remains unchanged, appropriately increasing the number of first grooves 1111 can reduce the size of a single groove, thereby reducing local stress concentration in the first pole piece 100. In addition, different shapes of first grooves 1111, such as circular, square, or other shapes, can be designed based on the actual use of the first pole piece 100 to accommodate different application scenarios. Through these adjustments, better electrolyte retention can be achieved without sacrificing the structural stability of the first pole piece 100.

[0053] Specifically, in some embodiments, the spacing L1 between two adjacent first grooves 1111 satisfies: 1.2 mm ≤ L1 ≤ 1.8 mm. For example, L1 can be 1.2 mm, 1.4 mm, 1.6 mm, or 1.8 mm. The spacing L1 of the first grooves 1111 determines the relative positional relationship between the grooves, thereby affecting the uniformity of the distribution of the electrolyte on the first electrode 100. By controlling L1 between 1.2 mm and 1.8 mm, it can be ensured that the first grooves 1111 are neither too close to affect the mechanical strength of the first electrode 100, nor too dispersed to cause uneven distribution of the electrolyte. This spacing design allows the electrolyte to be evenly stored in each first groove 1111, improving the uniformity of the electrolyte inside the battery cell, thereby enhancing the stability during lithium ion migration and the cycle life of the battery cell.

[0054] It is understandable that in some embodiments, in order to further improve the performance of the battery cell, the spacing L1 of the first grooves 1111 can be adjusted to make it more suitable for different application scenarios. For example, in applications with high power output requirements, the number of first grooves 1111 can be increased by reducing the value of L1, thereby increasing the total storage capacity of the electrolyte and thus enhancing the energy density of the battery cell. In application environments that require long-term stable operation, a larger L1 value can be selected to reduce the number of first grooves 1111 and enhance the structural stability of the first pole piece 100. In addition, the distribution and flow of the electrolyte can be further optimized to improve the overall performance of the battery cell by changing the shape of the first grooves 1111 or increasing the connecting channels between the first grooves 1111.

[0055] Reference Figure 1 and Figure 3 In some embodiments, along the extension direction of the first electrode 100, the second bending region 210 covers the first bending region 110. The covering relationship between the second bending region 210 and the first bending region 110 means that the second bending region 210 of the first diaphragm 200 completely covers the first bending region 110 of the first electrode 100. This design can ensure that there is no gap between the first electrode 100 and the first diaphragm 200 at the bend of the battery cell, thereby preventing electrolyte leakage and ensuring sufficient retention of the electrolyte. At the same time, the coverage of the second bending region 210 also helps to strengthen the bond between the first electrode 100 and the first diaphragm 200, reduce the delamination phenomenon caused by external forces, and improve the reliability of the battery cell.

[0056] It is understood that in some embodiments, in order to further improve the structural stability and electrolyte retention capacity of the battery cell, various measures can be taken to strengthen the coverage of the second bend region 210 on the first bend region 110. For example, the width of the second bend region 210 can be increased so that it extends beyond the edge of the first bend region 110 by a certain distance. This ensures that the second bend region 210 always covers the first bend region 110 even if there are errors during the manufacturing process. In addition, a layer of adhesive can be added between the first diaphragm 200 and the first pole piece 100 to enhance the bonding between the two and reduce the risk of separation due to environmental changes. These improvements help improve the performance of the battery cell under extreme conditions and extend the service life of the battery cell.

[0057] Reference Figure 3In some embodiments, the particle size D1 of the support particles 400 is in the range of 5μm ≤ D1 ≤ 8μm. For example, the particle size D1 of the support particles 400 can be 5μm, 6μm, 7μm, or 8μm. The main function of the support particles 400 in the battery cell structure is to provide additional liquid retention space to ensure the retention of electrolyte in the bend area of ​​the battery cell. The size of the particle size D1 of the support particles 400 directly affects the distribution density of the support particles 400 in the second bend area 210 and the size of the gaps between them, which in turn affects the storage capacity of the electrolyte. By controlling the particle size D1 between 5μm and 8μm, it can be ensured that the support particles 400 provide sufficient electrolyte storage space while not increasing the manufacturing difficulty due to too small a particle size, nor reducing the electrolyte storage space due to too large a particle size. This design allows the battery cell to maintain a high electrolyte content in the bend area, thereby ensuring stability during lithium ion migration and improving the service life and safety of the battery cell.

[0058] It is understandable that in some embodiments, in order to further optimize the performance of the battery cell, the storage capacity and distribution of the electrolyte can be adjusted by adjusting the particle size of the support particles 400. For example, in some application scenarios, a higher electrolyte storage density may be required. At this time, the upper limit value of the particle size D1 of the support particles 400 can be appropriately reduced to increase the number of support particles 400, thereby increasing the storage space for the electrolyte. On the other hand, if it is necessary to reduce manufacturing costs or simplify the production process, the lower limit value of the particle size D1 of the support particles 400 can be appropriately increased, the number of support particles 400 can be reduced, and the production process can be simplified. In addition, the physical properties of the support particles 400 can be adjusted by changing their material or shape to further improve the overall performance of the battery cell.

[0059] Reference Figure 3 In some embodiments, the support particles 400 are elastic so that a larger volume of support particles 400 can be used to reserve more space for storing electrolyte. In addition, the design of the elastic support particles 400 allows the support particles 400 to deform when the battery cell is subjected to external pressure or deformation, releasing or absorbing the stress generated by the deformation, thereby protecting the internal structure of the battery cell from damage. When the battery cell is squeezed or collided, the elastic support particles 400 can act as a buffer to avoid directly transmitting external force to the electrolyte storage area, reducing the risk of electrolyte leakage. In addition, the elastic support particles 400 can also adapt to the thermal expansion and contraction of the battery cell at different temperatures, ensuring that good electrolyte storage performance can be maintained in any environment, thereby improving the reliability of the battery cell.

[0060] It is understood that in some embodiments, in order to achieve better battery cell performance, materials with specific elasticity and recovery capabilities can be selected to make the support particles 400. For example, a material with a high rebound rate can be selected to ensure that after being subjected to external force, the support particles 400 can quickly return to their original shape and continue to perform their liquid retention function. In addition, the elastic coefficient of the support particles 400 can be adjusted to adapt to different types of battery cells and usage environments. For example, in applications requiring higher safety, a material with a higher elastic coefficient can be selected to enhance the protection of the battery cell. These improvements all help to improve the performance and safety of the battery cell in complex environments.

[0061] Reference Figure 1 and Figure 2 In some embodiments, the cell structure further includes a second electrode sheet 300. The second electrode sheet 300 is located on a side of the first diaphragm 200 facing away from the first electrode sheet 100, and the second electrode sheet 300 has a third bending region 310 corresponding to the first bending region 110. The first electrode sheet 100 can be either a positive electrode sheet or a negative electrode sheet, and the second electrode sheet 300 can be either a positive electrode sheet or a negative electrode sheet. When the first electrode sheet 100 is a positive electrode sheet, the second electrode sheet 300 is a negative electrode sheet. When the first electrode sheet 100 is a negative electrode sheet, the second electrode sheet 300 is a positive electrode sheet.

[0062] The third bend region 310 is recessed toward the surface of the first diaphragm 200 to form a plurality of second grooves 311, each of which is used to accommodate electrolyte. Providing the third bend region 310 on the second electrode sheet 300 increases the contact area between the second electrode sheet 300 and the first electrode sheet 100 in the bend region, thereby increasing the storage space for the electrolyte. The presence of the second grooves 311 further enhances the electrolyte storage capacity of the battery cell in the bend region, ensuring an adequate supply of electrolyte during lithium ion migration and thereby improving the electrolyte retention of the battery cell.

[0063] It is understood that in some embodiments, the design of the second pole piece 300 can be optimized to further enhance the overall performance of the battery cell. For example, a microstructure can be added to the second pole piece 300, such as configuring the inner wall of the second groove 311 with a capillary structure to enhance the liquid retention capacity of the second groove 311. Furthermore, auxiliary materials, such as a reinforced coating, can be added between the second pole piece 300 and the first separator 200 to improve the bonding strength between the second pole piece 300 and the first separator 200, further enhancing the stability and durability of the battery cell. These improvements all contribute to improving the overall performance of the battery cell.

[0064] Reference Figure 4In some embodiments, the first pole piece 100 is a negative pole piece, and the first pole piece 100 includes a long fabric area 120 and a short fabric area 130 that are relatively arranged. The surface density of the long fabric area 120 is 0.5% to 1% greater than the surface density of the short fabric area 130. This structural design of the first pole piece 100 enables the battery cell to have a higher energy density under the same volume. By slightly increasing the surface density of the long fabric area 120, the battery cell's storage capacity can be improved without significantly increasing the battery cell's weight. At the same time, this differentiated surface density design can also improve the uniformity of the current distribution inside the battery cell, reduce the heat caused by uneven current distribution, and enhance the safety performance of the battery cell. In addition, this design is also beneficial to improving the cycle life of the battery cell, because during the cyclic charge and discharge process, the higher surface density area can better resist the shedding of active materials and reduce the rate of battery cell capacity decay.

[0065] It is understood that in some embodiments, in order to further optimize the performance of the battery cell, the surface density ratio of the long fabric area 120 and the short fabric area 130 can be adjusted according to specific usage requirements. For example, in application scenarios that pursue higher energy density, the surface density of the long fabric area 120 can be appropriately increased to improve the energy density of the battery cell; in situations where safety is important, the increase in the surface density of the long fabric area 120 can be appropriately reduced to ensure the stability of the battery cell. In addition, the overall performance of the battery cell can be further improved to meet the needs of different application scenarios by changing the chemical composition of the first pole piece 100 or using special coatings. These adjustments help to improve the overall performance of the battery cell without sacrificing other performance characteristics.

[0066] Below, an embodiment is used to systematically explain the cell structure of the present application. Figures 1 to 4 Specifically, the battery cell structure of the present application includes a first electrode 100, a second electrode 300, and a first separator 200, with electrolyte filled therebetween. The first electrode 100 has a first bending region 110, the first separator 200 has a second bending region 210 corresponding to the first bending region 110, and the second electrode 300 has a third bending region 310 corresponding to the first bending region 110. The first bending region 110 is provided with a first groove 1111 for retaining electrolyte, the second bending region 210 is provided with a second groove 311 for retaining electrolyte, and the third bending region 310 is coated with support particles 400 for retaining electrolyte. As a result, the battery cell structure of the present application can always retain sufficient electrolyte at the bend to facilitate the migration of lithium ions, thereby improving the lithium plating phenomenon of the battery cell structure of the present application.

[0067] Furthermore, in order to ensure that the first pole piece 100 and the second pole piece 300 have good mechanical stability and good ability to retain electrolyte, the range of the aperture R1 of the first groove 1111 satisfies 50μm≤R1≤100μm, and the range of the aperture R2 of the second groove 311 satisfies 50μm≤R2≤100μm; the depth h1 of the first groove 1111 and the thickness H1 of the first pole piece 100 satisfy the relationship 0.2≤h1 / H1≤0.3, and the depth h2 of the second groove 311 and the thickness H2 of the second pole piece 300 satisfy the relationship 0.2≤h2 / H2≤0.3; the spacing L1 between two adjacent first grooves 1111 satisfies 1.2mm≤L1≤1.8mm, and the spacing L2 between two adjacent second grooves 311 satisfies 1.2mm≤L2≤1.8mm. Of course, it is understandable that the first groove 1111 and the second groove 311 can also be a concave hole structure that has the ability to retain electrolyte. For example, after the first electrode 100 and the second electrode 300 are rolled, the first bending area 110 of the first electrode 100 and the second bending area 210 of the second electrode 300 are vertically punched so that the punched concave holes meet the above relationship. These concave holes are all used to store electrolyte.

[0068] Furthermore, the second bend region 210 of the first separator 200 is coated on both sides with large PMMA particles, with a D50 of 5-8μm. "D50: 5-8μm" is a parameter representing the size distribution of the support particles 400, specifically the median particle size. "D50" here represents the particle size corresponding to the 50th percentile (i.e., median) of the cumulative distribution. This refers to the particle size distribution where particles smaller than this size account for 50% of the total volume (or mass), while particles larger than this size also account for 50%. Simply put, it is the diameter of the particle located in the center after all particles are arranged in order of size. Large PMMA particles are compressible, so during formation, the corners are not compressed, and the large particles maintain their original shape. The gaps between the particles provide storage space for the electrolyte, further increasing the liquid retention space in the corners.

[0069] Furthermore, the length of the area of ​​the first diaphragm 200 coated with PMMA is approximately 1.1 to 1.3 times the length of the battery cell corner, ensuring that the treated first diaphragm 200 completely covers the punched corner material area 111, that is, the second bending area 210 completely covers the first bending area 110 and the third bending area 310.

[0070] In summary, the cell structure of the present application can ensure that sufficient electrolyte is stored in the corners of the cell, and lithium ions can be quickly transferred through the electrolyte, thereby improving the lithium plating situation.

[0071] In addition, the battery cell structure of the present application adopts a positive and negative surface design to ensure that the lithium transmitted through the electrolyte has sufficient lithium vacancies on both sides of the negative electrode to accommodate it. Specifically, the positive and negative surface design of the negative electrode sheet ensures that the theoretical long fabric area and the short fabric area of ​​the negative electrode have basically the same CB value (the ratio of the compaction density of different parts, such as the ratio of the compaction density of the long fabric area and the short fabric area), and the long fabric area and the short fabric area of ​​the negative electrode sheet have basically the same lithium vacancies, ensuring that the lithium transmitted through the electrolyte has sufficient lithium vacancies on both sides of the negative electrode to accommodate it. Furthermore, the surface density of the long fabric area of ​​the negative electrode sheet is approximately 0.5% to 1% greater than that of the short fabric area. This design is used to further optimize the performance of the battery cell structure of the present application.

[0072] The above are only preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cell structure, characterized in that: include: A first pole piece having a first bending region; a first diaphragm, attached to the first pole piece, the first diaphragm having a second bending area corresponding to the first bending area; a plurality of support particles coated on the second bending region, wherein the gaps between the plurality of support particles are used to accommodate electrolyte; The first bending region is recessed toward the surface of the first diaphragm to form a plurality of first grooves, and the plurality of first grooves are all used to accommodate the electrolyte.

2. The battery core structure according to claim 1, characterized in that: The range of the aperture R1 of the first groove is: 50 μm≤R1≤100 μm.

3. The battery core structure according to claim 1, characterized in that: The depth h1 of the first groove and the thickness H1 of the first pole piece satisfy the relationship: 0.2≤h1 / H1≤0.

3.

4. The battery core structure according to claim 1, characterized in that: The first grooves are spaced apart from each other.

5. The battery core structure according to claim 4, characterized in that: The distance L1 between two adjacent first grooves satisfies: 1.2 mm ≤ L1 ≤ 1.8 mm.

6. The battery cell structure according to claim 1, characterized in that: Along the extension direction of the first pole piece, the second bending region covers the first bending region.

7. The battery core structure according to claim 1, characterized in that: The particle size D1 of the supporting particles is in the range of 5 μm≤D1≤8 μm.

8. The battery core structure according to claim 1, characterized in that: The supporting particles are elastic.

9. The battery core structure according to claim 1, characterized in that: The battery cell structure also includes a second pole piece, which is located on the side of the first diaphragm away from the first pole piece. The second pole piece has a third bending area corresponding to the first bending area. The third bending area is recessed toward the surface of the first diaphragm to form a plurality of second grooves, and the plurality of second grooves are all used to accommodate the electrolyte.

10. The battery core structure according to claim 1, characterized in that: The first electrode piece is a negative electrode piece, and the first electrode piece includes a long fabric area and a short fabric area that are arranged opposite to each other. The surface density of the long fabric area is 0.5% to 1% greater than the surface density of the short fabric area.

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