Battery

Abstract

The utility model discloses a battery which comprises a first pole piece, and the first pole piece comprises a concave-convex area and a clearance area which is arranged on the edge of at least one side of the concave-convex area along a first direction; first pits and second pits are formed in the concave-convex area, and the first pits are distributed on the edge of the concave-convex area in the second direction; in the first direction, the first pit is arranged between the clearance area and the second pit; the depth of the first concave pit in the third direction and the depth of the second concave pit in the third direction meet the following conditions: H = H1-H2, H is less than or equal to 10 microns, H1 is the depth of the first concave pit in the third direction, H2 is the depth of the second concave pit in the third direction, and H is the depth difference value of the first concave pit and the second concave pit in the third direction; the first direction, the second direction and the third direction are mutually vertical in pairs; the pit height consistency of the first pole piece is good, the interface of the first pole piece is smoother, the edge stress is released, the first pit is prevented from being broken, lithium precipitation at the edge of the first pole piece is avoided, and the safety of the battery is improved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery. Background Technology

[0002] Taking lithium batteries as an example, in recent years, with the widespread application of various electronic devices, the demand for lithium-ion batteries has been gradually expanding. At the same time, the market's requirements for the cycle performance of lithium-ion batteries are also increasing. To improve cycle performance, improvements are often made through design optimizations such as electrode materials, changes to electrode structure, and winding methods. Among these, implementing full-surface embossing and edge-avoiding embossing processes on the electrode surface has been proven in practice to significantly improve the cycle life of lithium-ion batteries, but the following problems still exist:

[0003] Because stress is concentrated on both sides during positive electrode embossing, existing full-surface embossing technology easily leads to a phenomenon where the hole depth is deeper at the edges and shallower in the middle. That is, the depth of the edge pits is greater than that of the pits in the center area. The uniformity of the embossed protrusion height of the electrode is poor because the stress on the edge pits is greater than that in other areas, and the stress is difficult to be fully released. As a result, the edge pits are prone to cracking, which further leads to adverse conditions such as lithium plating / polarization in the battery, affecting the battery's safety performance. Utility Model Content

[0004] The purpose of this invention is to provide a battery in which the height of the pits on the first electrode is more uniform, thus solving the technical problem that the safety performance of existing batteries is affected by the poor uniformity of the height of the pits on the electrode.

[0005] To achieve the above objectives, the present invention provides a battery, including a first electrode, the first electrode including a concave-convex region and a clearance region disposed along a first direction at at least one edge of the concave-convex region; the concave-convex region is formed with a first pit and a second pit, the first pit being distributed along a second direction at the edge of the concave-convex region; in the first direction, the first pit is disposed between the clearance region and the second pit.

[0006] The outer perimeter of the second pit is greater than the outer perimeter of the first pit; and / or, the volume of the second pit is greater than the volume of the first pit.

[0007] The depth of the first pit in the third direction and the depth of the second pit in the third direction satisfy: H=H1-H2, H≤10um, where H1 is the depth of the first pit in the third direction, H2 is the depth of the second pit in the third direction, and H is the difference between the depths of the first pit and the second pit in the third direction.

[0008] The first direction, the second direction, and the third direction are all perpendicular to each other.

[0009] Preferably, the outer perimeter of the first pit and the outer perimeter of the second pit satisfy the following: Where C1 is the outer perimeter of the first pit and C2 is the outer perimeter of the second pit.

[0010] Preferably, the volumes of the first pit and the second pit satisfy the following: Where V1 is the volume of the first pit and V2 is the volume of the second pit.

[0011] Preferably, the first recess includes a curved portion and an arc portion connected along a first direction, the curved portion being located on the side of the first recess away from the second recess, and the arc portion being located on the side of the first recess closer to the second recess.

[0012] Preferably, the curved portion includes straight segments and / or curved segments distributed along a third direction.

[0013] Preferably, the width of the curved portion in the first direction is smaller than the width of the arc portion in the first direction; the widths of the curved portion and the arc portion in the first direction satisfy the following: Where W1 is the width of the curved portion in the first direction, and W2 is the width of the arc portion in the first direction.

[0014] Preferably, the width of the clearance area in the first direction and the width of the first recess in the first direction satisfy: 1.3W≤L≤4.2W, where L is the width of the clearance area in the first direction and W is the width of the first recess in the first direction.

[0015] Preferably, the distance between the first and second recesses in the first direction and the width of the curved portion in the first direction satisfy: 0.7W1≤T1≤3W1, where T1 is the distance between the first and second recesses in the first direction and W1 is the width of the curved portion in the first direction.

[0016] Furthermore, the number of the first pit, the number of the second pit, the width of the first electrode in the first direction, and the spacing between the first pit and the second pit in the first direction satisfy the following: Where Q1 is the number of first pits, Q2 is the number of second pits, N1 is the width of the first electrode in the first direction, and T1 is the distance between the first pits and the second pits in the first direction.

[0017] Preferably, it further includes a wound battery cell, which includes a first electrode, a first diaphragm, a second electrode, and a second diaphragm stacked sequentially from the outside to the inside.

[0018] Preferably, the uneven area includes a first pit group and a second pit group arranged in a row along a first direction, and the first pit group and the second pit group are arranged alternately along a second direction;

[0019] Each column of first pits includes two first pits and several second pits that are equally spaced between the two first pits along a first direction;

[0020] Each column of the second pit group includes several second pits that are equally spaced along the first direction;

[0021] In this arrangement, all the second pits in each column of the first pit group are staggered from all the second pits in each column of the second pit group along a first direction.

[0022] Compared to the prior art, the present invention optimizes the structure of the first electrode of the battery. The optimized first electrode includes a concave-convex region and a clearance region disposed along a first direction at at least one edge of the concave-convex region. The concave-convex region forms a first pit and a second pit. The first pit is distributed along a second direction at the edge of the concave-convex region. In the first direction, the first pit is disposed between the clearance region and the second pit to ensure that the clearance region remains flat, reduce the corona phenomenon on the surface of the first electrode, improve the processing quality of the first electrode, and thus improve the safety performance of the battery.

[0023] Furthermore, in this invention, the depth of the first pit in the third direction and the depth of the second pit in the third direction satisfy: H = H1 - H2, H ≤ 10 μm, where H1 is the depth of the first pit in the third direction, H2 is the depth of the second pit in the third direction, and H is the difference between the depths of the first pit and the second pit in the third direction. This makes the depths of the first pit and the second pit closer, resulting in better consistency in the pit height of the first electrode. This ensures a smoother interface of the first electrode after formation, fully releases edge stress, reduces the risk of cracking of the first pit, avoids adverse conditions such as lithium plating / polarization at the edges of the first electrode, and improves battery safety. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a structural diagram of the first electrode of the battery provided in an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Cross-sectional schematic diagram of the central shelter area, the first pit, and the second pit;

[0027] Figure 3 This is a cross-sectional schematic diagram of the wound cell of the battery provided in an embodiment of the present invention.

[0028] The attached figures are labeled as follows:

[0029] First electrode 1, first diaphragm 2, second electrode 3, and second diaphragm 4;

[0030] Concave-convex area 11 and clearance area 12;

[0031] First pit 111 and second pit 112;

[0032] Curved section 1111 and arc section 1112;

[0033] First pit group 1101 and second pit group 1102. Detailed Implementation

[0034] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0035] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This utility model discloses a battery, as shown in the attached figure. Figure 1 As shown, the device includes a first electrode 1, which includes an embossed area and a clearance area 12. The raised / lowered area 11 is formed by embossing with an embossing roller. The raised / lowered area 11 has a first recess 111 and a second recess 112. The first recess 111 is distributed along a second direction at the edge of the raised / lowered area 11, and the remaining area of ​​the raised / lowered area 11 is filled with the second recess 112. In a first direction, the width of the second recess 112 is greater than the width of the first recess 111.

[0037] In the first direction, as shown in the appendix Figure 1 and 2 As shown, the first recess 111 is located between the clearance area 12 and the second recess 112 to ensure that the clearance area 12 remains flat, reduce the corona phenomenon on the surface of the first electrode 1, improve the processing quality of the first electrode 1, and thus improve the safety performance of the battery.

[0038] As attached Figure 2As shown, the outer perimeter of the second pit is greater than that of the first pit; and / or, the volume of the second pit is greater than that of the first pit; the depth of the first pit 111 in the third direction and the depth of the second pit 112 in the third direction satisfy: H=H1-H2, H≤10um, where H1 is the depth of the first pit 111 in the third direction, H2 is the depth of the second pit 112 in the third direction, and H is the difference between the depths of the first pit 111 and the second pit 112 in the third direction, making the depths of the first pit 111 and the second pit 112 closer, and the pit height of the first electrode 1 is more consistent, ensuring that the interface of the first electrode 1 after formation is smoother, the edge stress is fully released, reducing the risk of cracking of the first pit 111, avoiding adverse conditions such as lithium plating / polarization at the edge of the first electrode 1, and improving the safety of the battery.

[0039] It should be noted that, as shown in the attached document... Figure 1 and 2 As shown, the first direction, the second direction, and the third direction are mutually perpendicular. The first direction in this text can be the width direction of the first electrode 1, specifically, it can be the direction shown in the attached diagram. Figure 1 The X-axis direction; the second direction can be the length direction of the first pole piece 1, specifically it can be the attached... Figure 1 The Y-axis direction; the third direction can be the thickness direction of the first electrode 1, specifically the attached... Figure 2 The Z-axis direction in the middle. Of course, the directions pointed to by the first direction and the second direction can be interchanged, that is, the first pit 111 can be distributed along the length direction of the first electrode 1 on the edge of the concave and convex area 11, or it can be distributed along the width direction of the first electrode 1 on the edge of the concave and convex area 11.

[0040] In some embodiments, as shown in the appendix Figure 2 As shown, the outer perimeter of the second recess 112 is greater than the outer perimeter of the first recess 111; the outer perimeter of the first recess 111 and the outer perimeter of the second recess 112 satisfy the following: Wherein, C1 is the outer perimeter of the first pit 111 and C2 is the outer perimeter of the second pit 112; this can effectively ensure that the area occupied by the first pit 111 and the area occupied by the second pit 112 achieve a matching elongation, prevent the edge of the first electrode 1 from wrinkling due to the mismatch in elongation, and improve the stability of battery performance.

[0041] In some embodiments, the volume of the second recess 112 is greater than the volume of the first recess 111; the volumes of the first recess 111 and the second recess 112 satisfy the following: Where V1 is the volume of the first pit 111 and V2 is the volume of the second pit 112; by limiting the volume ratio of the first pit 111 and the second pit 112, not only can the first pit 111 not affect the electrolyte's better penetration into the central area of ​​the cell, ensuring a better electrolyte wetting effect in the central area of ​​the cell, effectively preventing lithium plating in the central area of ​​the cell and improving the cycle life of the battery; but it can also ensure that the first pit 111 has sufficient liquid storage capacity, better solving the problem of more severe lithium plating at the edge of the first electrode 1, and improving the safety performance of the battery.

[0042] In some embodiments, as shown in the appendix Figure 2 As shown, the first recess 111 includes a curved portion 1111 and an arc portion 1112 connected along a first direction. The curved portion 1111 is located on the side of the first recess 111 away from the second recess 112, and the arc portion 1112 is located on the side of the first recess 111 closer to the second recess 112. The curved portion 1111 is located between the arc portion 1112 and the clearance area 12. The arc portion 1112 is used to provide sufficient embossing support force to the first electrode 1, ensuring the basic appearance of the recessed area 11. The curved portion 1111 connects the arc portion 1112 and the clearance area 12, so that the edge stress on the arc portion 1112 is reasonably dispersed and released through the curved portion 1111, ensuring the flatness of the clearance area 12 and preventing premature cracking of the recesses on both sides of the edge of the recessed area 11, effectively improving the safety performance and cycle performance of the battery.

[0043] The curved section 1111 includes straight segments and / or curved segments distributed along a third direction; that is, the curved section 1111 can be only straight segments, or only curved segments, or a combination of straight segments and curved segments. The structure of the curved section 1111 is more diverse and is not specifically limited here.

[0044] In some embodiments, as shown in the appendix Figure 2 As shown, the width of the curved portion 1111 in the first direction is less than the width of the arc portion 1112 in the first direction; the widths of the curved portion 1111 in the first direction and the widths of the arc portion 1112 in the first direction satisfy the following: Wherein, W1 is the width of the curved portion 1111 in the first direction, and W2 is the width of the arc portion 1112 in the first direction, so that the curved portion 1111 and the arc portion 1112 cooperate with each other to ensure that the first pit 111 can provide sufficient embossing support force, and that the edge stress on the arc portion 1112 can be reasonably dispersed and released through the curved portion 1111, thereby avoiding the edge pit of the uneven area 11 from cracking earlier than other areas, which would affect the embossing effect; moreover, after the edge stress of the uneven area 11 is relieved, the embossing depth can be further increased, improving the embossing effect, which can improve the lithium plating problem of the battery to a greater extent and is conducive to improving the cycle performance of the battery.

[0045] In some embodiments, as shown in the appendix Figure 1 and 2 As shown, the width of the clearance area 12 in the first direction and the width of the first recess 111 in the first direction satisfy: 1.3W≤L≤4.2W, where L is the width of the clearance area 12 in the first direction and W is the width of the first recess 111 in the first direction. In this way, it can avoid the problem that the curved part 1111 of the first recess 111 cannot be fully extended due to the width of the clearance area 12 being too small, which would lead to insufficient stress release at the edge of the curved part 1111 and cause the edge of the first recess 111 to be easily broken, thus effectively improving the safety performance and cycle performance of the battery. At the same time, it can also avoid the problem that the width of the clearance area 12 is too small, which would affect the correction of the first electrode 1 and lead to poor winding coverage, thus improving the winding coverage yield.

[0046] In some embodiments, as shown in the appendix Figure 2 As shown, the distance between the first recess 111 and the second recess 112 in the first direction and the width of the curved portion 1111 in the first direction satisfy: 0.7W1≤T1≤3W1, where T1 is the distance between the first recess 111 and the second recess 112 in the first direction, and W1 is the width of the curved portion 1111 in the first direction.

[0047] And, as attached Figure 1 and 2 As shown, the number of first recesses 111, the number of second recesses 112, the width of the first electrode 1 in the first direction, and the spacing between the first recesses 111 and the second recesses 112 in the first direction satisfy the following: Where Q1 is the number of first recesses 111, Q2 is the number of second recesses 112, N1 is the width of the first electrode 1 in the first direction, and T1 is the distance between the first recesses 111 and the second recesses 112 in the first direction. If the distance between the first recesses 111 and the second recesses 112 in the first direction is too large, although the edge stress on the first recesses 111 can be reduced and the risk of edge recess breakage is lower, the embossing effect cannot be guaranteed. If the distance between the first recesses 111 and the second recesses 112 in the first direction is too small, the edge stress on the first recesses 111 increases exponentially, the risk of breakage of the first electrode 1 is greater, the depth of the embossing recesses is limited, and the embossing effect is difficult to achieve. In other words, this utility model ensures that the embossing effect of the first electrode 1 is optimal by controlling the distance between the first recesses 111 and the second recesses 112 in the first direction.

[0048] As attached Figure 3 As shown, the battery also includes a wound cell, which comprises a first electrode 1, a first separator 2, a second electrode 3, and a second separator 4 stacked sequentially from the outside to the inside to form the battery.

[0049] In some embodiments, as shown in the appendix Figure 1 As shown, the uneven area 11 includes a first pit group 1101 and a second pit group 1102 arranged in a row along a first direction, and the first pit group 1101 and the second pit group 1102 are arranged alternately along a second direction; each row of the first pit group 1101 includes two first pits 111 and several second pits 112 equally spaced between the two first pits 111 along the first direction; each row of the second pit group 1102 includes several second pits 112 equally spaced along the first direction; wherein, all the second pits 112 of each row of the first pit group 1101 and all the second pits 112 of each row of the second pit group 1102 are staggered along the first direction; to ensure that the pit distribution of the uneven area 11 is optimal, thereby achieving the best embossing effect of the first electrode 1.

[0050] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0051] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A battery, characterized in that, The device includes a first electrode (1), which includes a concave-convex region (11) and a clearance region (12) disposed along a first direction at least on one side edge of the concave-convex region (11); the concave-convex region (11) is formed with a first pit (111) and a second pit (112), the first pit (111) being distributed along a second direction at the edge of the concave-convex region (11); in the first direction, the first pit (111) is disposed between the clearance region (12) and the second pit (112); The outer perimeter of the second recess (112) is greater than the outer perimeter of the first recess (111); and / or, the volume of the second recess (112) is greater than the volume of the first recess (111); The depth of the first pit (111) in the third direction and the depth of the second pit (112) in the third direction satisfy: H=H1-H2, H≤10um, where H1 is the depth of the first pit (111) in the third direction, H2 is the depth of the second pit (112) in the third direction, and H is the difference between the depths of the first pit (111) and the second pit (112) in the third direction. The first direction, the second direction, and the third direction are all perpendicular to each other.

2. The battery according to claim 1, characterized in that, The outer perimeter of the first recess (111) and the outer perimeter of the second recess (112) satisfy the following: Wherein, C1 is the outer perimeter of the first pit (111), and C2 is the outer perimeter of the second pit (112).

3. The battery according to claim 1, characterized in that, The volumes of the first pit (111) and the second pit (112) satisfy the following: V1 is the volume of the first pit (111), and V2 is the volume of the second pit (112).

4. The battery according to claim 1, characterized in that, The first pit (111) includes a curved portion (1111) and an arc portion (1112) connected along the first direction. The curved portion (1111) is located on the side of the first pit (111) away from the second pit (112), and the arc portion (1112) is located on the side of the first pit (111) close to the second pit (112).

5. The battery according to claim 4, characterized in that, The curved portion (1111) includes straight line segments and / or curved segments distributed along the third direction.

6. The battery according to claim 4, characterized in that, The width of the curved portion (1111) in the first direction is less than the width of the arc portion (1112) in the first direction; the width of the curved portion (1111) in the first direction and the width of the arc portion (1112) in the first direction satisfy the following: Wherein, W1 is the width of the curved portion (1111) in the first direction, and W2 is the width of the arc portion (1112) in the first direction.

7. The battery according to claim 6, characterized in that, The width of the clearance area (12) in the first direction and the width of the first recess (111) in the first direction satisfy: 1.3W≤L≤4.2W, where L is the width of the clearance area (12) in the first direction and W is the width of the first recess (111) in the first direction.

8. The battery according to claim 7, characterized in that, The distance between the first recess (111) and the second recess (112) in the first direction and the width of the curved portion (1111) in the first direction satisfy: 0.7W1≤T1≤3W1, where T1 is the distance between the first recess (111) and the second recess (112) in the first direction, and W1 is the width of the curved portion (1111) in the first direction; And, the number of the first pit (111), the number of the second pit (112), the width of the first electrode (1) in the first direction, and the spacing between the first pit (111) and the second pit (112) in the first direction satisfy: Where Q1 is the number of the first pit (111), Q2 is the number of the second pit (112), N1 is the width of the first electrode (1) in the first direction, and T1 is the distance between the first pit (111) and the second pit (112) in the first direction.

9. The battery according to any one of claims 1 to 8, characterized in that, It also includes a wound cell, which includes a first electrode (1), a first diaphragm (2), a second electrode (3), and a second diaphragm (4) stacked sequentially from the outside to the inside.

10. The battery according to claim 9, characterized in that, The uneven area (11) includes a first pit group (1101) and a second pit group (1102) arranged in a row along the first direction, and the first pit group (1101) and the second pit group (1102) are alternately arranged along the second direction; Each column of the first pit group (1101) includes two first pits (111) and a number of second pits (112) distributed at equal intervals between the two first pits (111) along the first direction. Each column of the second pit group (1102) includes a plurality of second pits (112) distributed at equal intervals along the first direction; In this arrangement, all the second pits (112) of each column of the first pit group (1101) and all the second pits (112) of each column of the second pit group (1102) are staggered along the first direction.

Images