Electrode sheets, battery cells, embossing rollers, and battery cell production equipment

Abstract

This invention discloses an electrode sheet, a battery cell, an embossing roller, and battery cell production equipment. The electrode sheet includes an electrode sheet body having a first surface and a second surface. Multiple recesses are formed on the first surface facing the second surface, arranged in multiple rows and columns. The depth of each recess gradually decreases from the center of the electrode sheet body towards its opposite sides. A greater depth provides more deformation space, and a smaller depth provides less deformation space. This satisfies the practical requirement that the deformation space of the electrode sheet gradually decreases from its center towards its opposite sides, ensuring that the depth of the recesses at each location on the electrode sheet fully matches the deformation space required for expansion at each location, thus greatly improving the reliability of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to electrode sheets, battery cells, embossing rollers, and battery cell production equipment. Background Technology

[0002] When a battery cell is in operation, the electrode plates expand due to heat. To accommodate this expansion, embossing rollers are typically used to create recesses on the electrode plate surface. This provides space for deformation, allowing the electrode plates to deform during charging and discharging, thus effectively preventing excessive expansion of the electrode plates. However, in existing technologies, the depth of the recesses on the electrode plate surface is uniform, while the actual expansion of the electrode plates at different locations is not consistent. This results in the depth of the recesses at some locations not perfectly matching the space required for the electrode plate's expansion, leading to some recesses being too large or too small. Summary of the Invention

[0003] In order to overcome at least one of the defects described in the prior art, the present invention provides an electrode sheet, a battery cell, an embossing roller, and a battery cell manufacturing apparatus, wherein the depth of the recesses formed at various positions of the electrode sheet is more matched with the deformation space required for the expansion of the electrode sheet at various positions.

[0004] The technical solution adopted by this invention to solve its problem is:

[0005] An electrode includes: an electrode body having a first surface and a second surface, wherein the first surface is recessed toward the second surface to form a plurality of recesses, the plurality of recesses being arranged in multiple rows and columns, and the depth of the plurality of recesses gradually decreasing from the middle portion of the electrode body toward the two opposite sides of the electrode body.

[0006] The beneficial effects of the electrode sheet provided by this invention are as follows: The surface of the electrode sheet is provided with multiple rows and columns of recesses to pre-provide deformation space for the electrode sheet to expand and deform during battery charging and discharging, effectively avoiding excessive expansion of the electrode sheet. More importantly, the depth of the multiple recesses gradually decreases from the center of the electrode sheet body towards the two opposite sides. The greater the depth of the recess, the greater the deformation space it provides; conversely, the smaller the depth of the recess, the smaller the deformation space it provides. This satisfies the practical requirement that the deformation space required for electrode sheet expansion should gradually decrease from the center of the electrode sheet body towards the two opposite sides, avoiding the problems of insufficient depth of the recesses near the center of the electrode sheet body and excessive depth of the recesses near the two opposite sides. This ensures that the depth of the recesses formed at each position of the electrode sheet body is fully matched with the deformation space required for expansion at each position of the electrode sheet body, greatly improving the reliability of the battery. Furthermore, the multiple recesses also help to increase the compaction density of the electrode sheet, thereby increasing the overall energy density of the battery.

[0007] According to some embodiments of the present invention, the thickness of the electrode plate without the recess at full charge is t1, and the thickness of the electrode plate without the recess at empty charge is t2. The expansion rate of the electrode plate is η, and η satisfies the relational expression: η = t1 / t2 - 1; the depth of the recess is H, and H is positively correlated with η.

[0008] According to some embodiments of the present invention, the recesses in adjacent rows are staggeredly distributed.

[0009] According to some embodiments of the present invention, the cross-section of the recess is circular or elliptical.

[0010] Another object of the present invention is to provide an electric core, which is formed by winding or stacking a plurality of electrode plates. The electrode plate includes an electrode plate body, and the electrode plate body has a first surface and a second surface. A plurality of recesses are formed by the first surface recessing towards the second surface. The plurality of recesses are arranged in multiple rows and multiple columns, and the depths of the plurality of recesses gradually decrease from the middle part of the electrode plate body to the two opposite sides of the electrode plate body.

[0011] According to some embodiments of the present invention, the thickness of the electrode plate without the recess at full charge is t1, and the thickness of the electrode plate without the recess at empty charge is t2. The expansion rate of the electrode plate is η, and η satisfies the relational expression: η = t1 / t2 - 1; the thickness of the electric core is T, the electric core has opposite first and second sides, the first side and / or the second side are used to set the pole ears, the distance between the first side and the second side is the height W of the electric core, the electrode plate has a center line located between the first side and the second side, and the center line is equidistant from the first side and the second side. The distance between the recess and the center line is s, and 0 < s < W / 2; the depth of the recess is H, and H satisfies the relational expression: H = T*η - 2*T*η*s / W.

[0012] Another object of the present invention is to provide an embossing roller for manufacturing the electrode plate as described above. The embossing roller includes an embossing body, and the embossing body is provided with a plurality of embossing protrusions. The embossing protrusions are divided into multiple rows and each row includes a plurality of the embossing protrusions. The multiple rows of embossing protrusions are arranged at intervals in a first direction, and the first direction is the length direction of the embossing body; the plurality of embossing protrusions and the plurality of recesses are matched.

[0013] According to some embodiments of the present invention, the distance between adjacent two rows of the embossing protrusions is L1, and the maximum dimension of the embossing protrusion in the first direction is d1. L1 and d1 satisfy the relational expression: 0.5d1 ≤ L1 ≤ d1.

[0014] According to some embodiments of the present invention, the spacing between adjacent embossed protrusions in the same row is L2, the maximum dimension of the embossed protrusion in the second direction is d2, the second direction is the arrangement direction of the embossed protrusions in the same row, and L2 and d2 satisfy the relationship: 0.5d2≤L2≤d2.

[0015] Another object of the present invention is to provide a battery cell manufacturing apparatus, including the embossing roller as described above, and a manufacturing mechanism for winding or stacking the electrode sheets to form a battery cell, wherein the embossing roller is located upstream of the manufacturing mechanism. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the electrode structure according to an embodiment of the present invention;

[0017] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the electrode plates arranged in the same row of recesses.

[0018] Figure 3 This is a schematic diagram of the cross-sectional structure of the embossing roller;

[0019] Figure 4 This is a schematic diagram of the battery cell structure;

[0020] Figure 5 The graph shows the functional relationship between H and s based on the actual parameters in Table 1.

[0021] The meanings of the reference numerals in the attached figures are as follows:

[0022] 1-Electrode sheet, 11-Electrode sheet body, 12-Recessed part, 2-Embossing roller, 21-Embossing body, 22-Embossing protrusion, 3-Battery cell, 31-Electrode tab, 32-First side, 33-Second side. Detailed Implementation

[0023] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0024] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0026] Please see Figure 1 and Figure 2 The present invention discloses an electrode 1, including an electrode body 11. The electrode body 11 has a first surface and a second surface. The first surface is recessed towards the second surface to form a plurality of recesses 12. The plurality of recesses 12 are arranged in multiple rows and columns, and the depth of the plurality of recesses 12 gradually decreases from the middle part of the electrode body 11 to the two opposite sides of the electrode body 11.

[0027] like Figure 1 As shown, specifically, in this embodiment, the depth of the recesses 12 in the same column is the same, and the depth of the recesses 12 in the same row gradually decreases from the middle part of the electrode body 11 to the two opposite sides of the electrode body 11. More specifically, when the electrode 1 is used to wind to form the battery cell 3, the winding direction of the electrode 1 is parallel to the arrangement direction of the recesses 12 in the same column.

[0028] By adopting the above scheme, multiple rows and columns of recesses 12 are provided on the surface of the electrode 1 to provide deformation space for the electrode 1 to expand and deform during battery charging and discharging. This effectively avoids the phenomenon of excessive expansion of the electrode 1. Furthermore, this distribution pattern allows the electrode 1 to deform more uniformly, avoiding the problem of excessive or insufficient pressure between adjacent recesses 12. More importantly, the depth of the multiple recesses 12 gradually decreases from the middle of the electrode body 11 to the two opposite sides of the electrode body 11. The greater the depth of the recess 12, the greater the deformation space it provides; the smaller the depth of the recess 12, the smaller the deformation space it provides. In this way, the required deformation space of the electrode 1 is satisfied, which is from the center of the electrode body 11 to the opposite sides of the electrode body 11. The actual working requirement of gradually decreasing depth on both opposite sides avoids the problems of insufficient depth of the recess 12 near the center of the electrode body 11 and excessive depth of the recess 12 on both opposite sides of the electrode body 11. This ensures that the depth of the recess 12 formed at each position of the electrode body 11 is fully matched with the deformation space required for the expansion of each position of the electrode body 11, greatly improving the reliability of the battery. In addition, multiple recesses 12 also help to increase the compaction density of the electrode 1, thereby increasing the energy density of the entire battery. Multiple recesses 12 can also increase the surface area and wettability of the electrode 1, thereby increasing the active area of ​​electrochemical reaction in the battery, reducing the cell DCR, increasing the cell power density, and making the cost of manufacturing high-power cells relatively lower.

[0029] Furthermore, in this embodiment, the thickness of the electrode 1 without the recess 12 when fully charged is t1, and the thickness of the electrode 1 without the recess 12 when uncharged is t2. The expansion rate of the electrode 1 is η, which satisfies the relationship: η = t1 / t2 - 1. It can be understood that the larger η is, the higher the degree of expansion of the electrode 1 under the same working load, and the larger the deformation space required for the expansion of the electrode 1. The depth of the recess 12 is H, and H is positively correlated with η. Thus, when other coefficients remain unchanged, the larger η is, the larger H is, so as to meet the deformation space required for the expansion of different types of electrode 1.

[0030] Specifically, the electrode 1 includes a positive electrode and a negative electrode. It is understood that the expansion of the negative electrode is greater than that of the positive electrode during battery charging and discharging. Therefore, in this embodiment, t1 is the thickness of the negative electrode without the recess 12 when fully charged.

[0031] It should be noted that in some other embodiments, t1 can also be the thickness of the positive electrode sheet without the recess 12 when fully charged.

[0032] It should be noted that in some other embodiments, the depth of the recess 12 can be determined based on the expansion rates of the positive and negative electrodes, respectively. Specifically, the thickness of the positive electrode without the recess 12 when fully charged is t3, and the expansion rate of the positive electrode is η1. Then η1 satisfies the relationship: t3 / t2-1, and the depth of the recess 12 on the positive electrode is H1, which is positively correlated with η1. The thickness of the negative electrode without the recess 12 when fully charged is t4, and the expansion rate of the negative electrode is η2. Then η2 satisfies the relationship: t4 / t2-1, and the depth of the recess 12 on the negative electrode is H2, which is positively correlated with η2.

[0033] Preferably, in this embodiment, the recesses 12 in adjacent rows are staggered, so that the recesses 12 are more evenly distributed on the surface of the electrode 1, thereby providing matching deformation space for each position of the electrode 1.

[0034] Preferably, in this embodiment, the cross-section of the recess 12 is circular or elliptical. This utilizes a relatively smooth surface to ensure that the deformation of the recess 12 is more uniform in all directions, and reduces stress concentration in the recess 12. Of course, in some other embodiments, the cross-section of the recess 12 can be polygonal or other irregular shapes depending on actual needs, and is not limited to the circular or elliptical shape of this embodiment.

[0035] like Figure 1 , Figure 2 and Figure 4As shown in the figure, another object of the present invention is to provide an electric cell 3, which is formed by winding or stacking a plurality of the above-mentioned electrode plates 1. The recessed part 12 of the electrode plate body 11 reserves a matching and sufficient deformation space for the expansion of the electrode plate 1. Therefore, the overall expansion deformation degree during the charge and discharge of the electric cell 3 can also be reduced, improving the overall reliability of the battery.

[0036] Furthermore, in this embodiment, the thickness of the electric cell 3 is T. Specifically, the thickness T of the electric cell 3 refers to the distance between the two large surfaces of the electric cell 3. And the electric cell 3 has opposite first side 32 and second side 33. The first side 32 and / or the second side 33 are used to set the electrode tab 31. The distance between the first side 32 and the second side 33 is the height W of the electric cell 3. The electrode plate 1 has a center line located between the first side 32 and the second side 33, and the distances from the center line to the first side 32 and the second side 33 are equal. The distance between the recessed part 12 and the center line is s, and 0 < s < W / 2; the depth H of the recessed part 12 satisfies the relational expression: H = T * η - 2 * T * η * s / W. Thus, when manufacturing a plurality of electrode plates 1 into electric cells 3 of different specifications and models, the depth H of the recessed part 12 not only needs to be obtained according to the expansion rate η of the electrode plate 1, but also needs to be obtained according to the thickness T of the electric cell 3, the height W of the electric cell 3, and the distance s between the recessed part 12 and the center line. According to this relational expression, the optimal depth required for the recessed part 12 at each position of the electrode plate 1 of the electric cells 3 of different specifications and models can be calculated, so as to reserve a more matching deformation space for the electric cells 3 of different specifications and models produced, in order to reduce the expansion deformation degree during the charge and discharge of the electric cells 3 of different specifications and models.

[0037] Specifically, Figure 5 shows the functional relationship formed by H and s according to the actual parameters in Table 1. The units of H and s are mm.

[0038] Table 1 is as follows:

[0039] Parameter name symbol numerical values unit Thickness of the negative electrode sheet without a recess when fully charged t1 82 μm Thickness of negative electrode sheet without recess when not in use t2 69 μm coefficient of expansion η 0.188 1 Cell thickness T 26 mm Cell height W 85 mm

[0040] In addition, as Figure 1 、 Figure 2 and Figure 3As shown in the figure, another object of the present invention is to provide an embossing roller 2 for manufacturing the electrode sheet 1 as described above. The embossing roller 2 includes an embossing body 21 provided with a plurality of embossing protrusions 22. The embossing protrusions 22 are arranged in multiple rows, and each row includes a plurality of embossing protrusions 22. The multiple rows of embossing protrusions 22 are arranged at intervals in the first direction, and the first direction is the length direction of the embossing body 21; the plurality of embossing protrusions 22 and the plurality of recessed portions 12 are matched. Specifically, the positions and shapes of the plurality of embossing protrusions 22 and the plurality of recessed portions 12 need to match each other, and the heights of the plurality of embossing protrusions 22 and the depths of the plurality of recessed portions 12 need to match each other. More specifically, in this embodiment, the cross-section of the embossing protrusion 22 is also circular or elliptical. Thus, with a relatively smooth surface, it is possible to better avoid the phenomenon of damaging the electrode sheet 1 during the embossing process.

[0041] More specifically, the length of the embossing body 21 is a, the distance from the embossing protrusion 22 to the midline of the embossing body 21 is b, and 0 < b < a / 2. The height of the embossing protrusion 22 is c, then c satisfies the relationship: c = T * η - 2 * T * η * b / a, where a corresponds to W, b corresponds to s, and c corresponds to H.

[0042] It can be understood that most of the existing embossing rollers 2 are made of metal materials. Although the embossing pressure required during the working process is small, the metal embossing roller 2 is very likely to generate metal debris during the pressing of the electrode sheet 1, which contaminates the electrode sheet 1 and thus affects the normal winding or stacking of the electrode sheet 1; and the metal embossing roller 2 is very likely to damage the electrode sheet 1, thereby increasing the rejection rate.

[0043] Therefore, preferably, in this embodiment, the embossing body 21 and the embossing protrusions 22 are made of plastic materials. Although the embossing pressure is increased, during the process of pressing the electrode sheet 1, it will neither generate metal debris to affect the normal winding of the electrode sheet 1 nor damage the electrode sheet 1, reducing the rejection rate of the electrode sheet 1. It should be noted that in the embodiments of the present invention, the embossing body 21 and the embossing protrusions 22 can be made of plastics such as polyethylene, polyvinyl chloride, and polystyrene, or can be made of synthetic rubber materials such as cis-butadiene rubber, styrene-butadiene rubber, nitrile rubber, and chloroprene rubber, and can be specifically selected according to actual needs.

[0044] It can be understood that the distance between two adjacent rows of embossing protrusions 22 is L1, and the maximum dimension of the embossing protrusion 22 in the first direction is d1. The first direction is the length direction of the embossing roller 2. If the distance L1 between two adjacent rows of embossing protrusions 22 is too large, the embossing marks on the electrode sheet 1 will be sparse, which is not conducive to improving the compaction density inside the battery cell 3, while if the distance L1 between two adjacent rows of embossing protrusions 22 is too small, the probability of damage to the electrode sheet 1 will increase.

[0045] Such as Figure 1 And Figure 3 As shown, the value of L1 is equal to the distance between two adjacent recesses 12 in the same row arranged along the first direction, and the value of d1 is equal to the maximum size of the recess 12 in the first direction. In this embodiment, preferably, L1 and d1 satisfy the relationship: 0.5d1≤L1≤d1. Thus, by controlling the spacing L1 between two adjacent rows of embossed protrusions 22 to be between 0.5 and 1 times the maximum size d1 of the embossed protrusions 22 along the first direction, it is possible to ensure that the indentation of the electrode 1 is relatively dense, thereby improving the compaction density inside the cell 3 and reducing the probability of electrode 1 breakage. Of course, in other embodiments of the present invention, the spacing L1 between two adjacent rows of embossed protrusions 22 can be selected according to actual needs and is not limited to the above limitation.

[0046] It is understandable that the spacing between adjacent embossed protrusions 22 in the same row is L2, and the maximum dimension of the embossed protrusions 22 in the second direction is d2. The second direction is the arrangement direction of the embossed protrusions 22 in the same row. If the spacing L2 between adjacent embossed protrusions 22 in the same row is too large, it will cause the indentations on the electrode 1 to be sparse, which is not conducive to improving the compaction density of the battery cell. If the spacing L2 between adjacent embossed protrusions 22 in the same row is too small, it will increase the probability of the electrode 1 being damaged.

[0047] like Figure 1 As shown, the value of L2 is equal to the distance between two adjacent recesses 12 in the same row arranged along the second direction, and the value of d2 is equal to the maximum size of the recess 12 in the second direction. In this embodiment, preferably, L2 and d2 satisfy the relationship: 0.5d2≤L2≤d2. Thus, by controlling the spacing L2 between adjacent embossed protrusions 22 in the same row to be between 0.5 and 1 times the maximum size d2 of the embossed protrusion 22 along the second direction, it is possible to ensure that the indentation of the electrode 1 is relatively dense, thereby improving the compaction density inside the cell 3 and reducing the probability of electrode 1 breakage. Of course, in other embodiments of the present invention, the spacing L2 between adjacent embossed protrusions 22 in the same row can be selected according to actual needs and is not limited to the above limitation.

[0048] Another object of the present invention is to provide a battery cell manufacturing apparatus, including the embossing roller 2 as described above, and a manufacturing mechanism for winding or stacking electrode sheets 1 to form a battery cell 3. The embossing roller 2 is located upstream of the manufacturing mechanism. With this configuration, in actual production, since the embossing roller 2 is located upstream of the manufacturing mechanism, after embossing the electrode sheets 1, the manufacturing mechanism can be used directly to wind or stack the electrode sheets 1 to form the battery cell 3. This avoids deformation of the embossed shape caused by winding the electrode sheets 1 after embossing in the rolling process, and also avoids the embossed shape of the electrode sheets 1 rebounding due to a long resting time after embossing in the rolling process. This ensures the compaction density of the electrode sheets 1 and alleviates the problem of excessive expansion of the electrode sheets 1 during charging and discharging.

[0049] In summary, the electrode sheet, battery cell, embossing roller, and battery cell manufacturing equipment disclosed in this invention can bring at least the following beneficial technical effects:

[0050] 1) It satisfies the actual working requirement that the deformation space required for the expansion of the electrode 1 needs to gradually decrease from the center of the electrode body 11 to the two opposite sides of the electrode body 11, so that the depth of the recess 12 formed at each position of the electrode body 11 is fully matched with the deformation space required for the expansion at each position of the electrode body 11, which greatly improves the reliability of the battery.

[0051] 2) H and η are positively correlated to satisfy the deformation space required for the expansion of different types of electrode 1;

[0052] 3) According to the relationship H=T*η-2*T*η*s / W, the optimal depth required for the recess 12 at each position of the electrode 1 of the battery cell 3 of different specifications and models can be calculated, so as to reserve a more suitable deformation space for the battery cells 3 of different specifications and models produced, so as to alleviate the degree of expansion deformation of the battery cells 3 of different specifications and models during charging and discharging.

[0053] 4) It avoids deformation of the embossed shape caused by winding up the electrode sheet 1 after the embossing process in the rolling process, and also avoids the embossed shape of the electrode sheet 1 rebounding due to a long resting time after the embossing process in the rolling process.

[0054] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. An electrode, characterized in that, The electrode is used to wind and form a battery cell, the electrode comprising: The electrode body (11) has a first surface and a second surface. The first surface is recessed towards the second surface to form a plurality of recesses (12), and the plurality of recesses (12) protrude from the second surface. The plurality of recesses (12) are arranged in multiple rows and columns. The plurality of recesses (12) in the same column have the same depth. The depth of the plurality of recesses (12) in the same row gradually decreases from the middle part of the electrode body (11) to the two opposite sides of the electrode body (11). The winding direction of the electrode is parallel to the arrangement direction of the plurality of recesses (12) in the same column.

2. The electrode sheet according to claim 1, characterized in that, The thickness of the electrode (1) without the recess (12) when fully charged is t1, and the thickness of the electrode (1) without the recess (12) when uncharged is t2. The expansion rate of the electrode (1) is η, which satisfies the relationship: η=t1 / t2-1; The thickness of the battery cell (3) is T. The battery cell (3) has a first side (32) and a second side (33) opposite each other in the arrangement direction of a plurality of recesses (12) in the same row. The first side (32) and / or the second side (33) are used to set the tabs (31). The distance between the first side (32) and the second side (33) is the height W of the battery cell. The electrode (1) has a center line located between the first side (32) and the second side (33). The center line is equidistant from the first side (32) and the second side (33). The distance between the recess (12) and the center line is s, and 0 <s<W / 2; The depth of the recess (12) is H, and H satisfies the relationship: H=T*η-2*T*η*s / W.

3. The electrode sheet according to claim 1, characterized in that, The recesses (12) in adjacent rows are staggered.

4. The electrode sheet according to any one of claims 1-3, characterized in that, The cross-section of the recess (12) is circular or elliptical.

5. A battery cell, formed by winding electrode sheets (1), characterized in that, The electrode (1) includes an electrode body (11) and a plurality of recesses (12). The electrode body (11) has a first surface and a second surface. The first surface is recessed towards the second surface to form a plurality of recesses (12). The plurality of recesses (12) protrude from the second surface. The plurality of recesses (12) are arranged in multiple rows and columns. The plurality of recesses (12) in the same column have the same depth. The depth of the plurality of recesses (12) in the same row gradually decreases from the middle part of the electrode body (11) to the two opposite sides of the electrode body (11). The winding direction of the electrode is parallel to the arrangement direction of the plurality of recesses (12) in the same column.

6. The battery cell according to claim 5, characterized in that, The thickness of the electrode (1) without the recess (12) is t1 when fully charged, and the thickness of the electrode (1) without the recess (12) is t2 when uncharged. The expansion rate of the electrode (1) is η, and η satisfies the relationship: η=t1 / t2-1. The thickness of the battery cell (3) is T. The battery cell (3) has a first side (32) and a second side (33) opposite each other in the arrangement direction of a plurality of recesses (12) in the same row. The first side (32) and / or the second side (33) are used to set the tabs (31). The distance between the first side (32) and the second side (33) is the height W of the battery cell. The electrode (1) has a center line located between the first side (32) and the second side (33). The center line is equidistant from the first side (32) and the second side (33). The distance between the recess (12) and the center line is s, and 0 <s<W / 2; The depth of the recess (12) is H, and H satisfies the relationship: H=T*η-2*T*η*s / W.

7. An embossing roller, characterized in that, For manufacturing an electrode sheet (1) as described in any one of claims 1-4, the embossing roller includes an embossing body (21), the embossing body (21) is provided with a plurality of embossing protrusions (22), the embossing protrusions (22) are arranged in multiple rows and each row includes a plurality of the embossing protrusions (22), the multiple rows of the embossing protrusions (22) are spaced apart along a first direction, the first direction being the length direction of the embossing body (21); the plurality of the embossing protrusions (22) and the plurality of the recesses (12) are matched.

8. The embossing roller according to claim 7, characterized in that, The spacing between two adjacent rows of embossed protrusions (22) is L1, and the maximum dimension of the embossed protrusions (22) in the first direction is d1. L1 and d1 satisfy the relationship: 0.5d1≤L1≤d1.

9. The embossing roller according to claim 7, characterized in that, The spacing between adjacent embossed protrusions (22) in the same row is L2, and the maximum dimension of the embossed protrusion (22) in the second direction is d2. The second direction is the arrangement direction of the embossed protrusions (22) in the same row. L2 and d2 satisfy the relationship: 0.5d2≤L2≤d2.

10. Battery cell production equipment, characterized in that, The device includes the embossing roller (2) as described in any one of claims 7-9, and also includes a manufacturing mechanism for winding or stacking the electrode sheet (1) to form a battery cell, wherein the embossing roller (2) is located upstream of the manufacturing mechanism.

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