Battery cell pole piece, battery cell and secondary battery

Abstract

The utility model belongs to the technical field of batteries, and particularly relates to a battery cell pole piece, a battery cell and a secondary battery cell. Wherein the battery cell pole piece comprises a current collector and an active material layer arranged on at least one surface of the current collector; in the width direction of the current collector, the active material layer is provided with a slot area and a bulge area; at least one convex point is arranged in the convex area; in the length direction of the current collector, the slot area comprises at least two processing subareas and a clearance area; each clearance area is arranged between every two adjacent processing subareas; at least one groove is formed in the processing subarea; and a tab groove is formed in the clearance area. According to the utility model, the contact area between the electrolyte and the pole piece can be increased, so that the accommodating efficiency and wettability of the electrolyte are improved.

Description

Technical Field

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

[0002] Currently, countries around the world are vigorously developing green energy. Lithium-ion batteries, with their high energy density, long cycle life, and environmental friendliness, have become the main power source for consumer electronics and electric vehicles. As society continues to develop, people are placing increasingly higher demands on the capacity of lithium-ion batteries. The number of winding layers in the battery cell is increasing, and the thickness of the positive and negative electrodes is also growing. This reduces the rate-discharge performance of the battery cell and increases the risk of lithium plating during cycling. Simultaneously, ensuring the electrodes are properly wetted by the electrolyte has become a challenge. Currently, most methods for improving rate performance and electrode wettability primarily rely on electrode embossing technology. Electrode embossing technology creates concave and convex patterns on the electrode through opposing extrusion, producing electrolyte storage grooves to improve kinetic performance and address electrolyte wetting issues and rate-discharge performance. When the tabs and protective adhesive of a wound battery cell pass through the embossing device, they need to be separated from the embossing area to prevent pressure on the tabs from affecting conductivity or the adhesive from detaching and losing its protective effect. Since the embossing device is mostly driven by electric or ventilated valves, the movement has a certain delay, which requires a wider tab clearance area and adhesive paper clearance area on the electrode sheet, affecting the wetting effect of these parts of the electrode sheet. Utility Model Content

[0003] The purpose of this utility model is to provide a battery cell electrode, battery cell, and secondary battery that can solve the technical problem of poor wetting effect in the prior art, in order to address the shortcomings of the existing technology.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A battery cell electrode includes a current collector and an active material layer disposed on at least one surface of the current collector;

[0006] In the width direction of the current collector, the active material layer is provided with a groove area and a raised area; the raised area is provided with at least one protrusion.

[0007] Along the length of the current collector, the slot area includes at least two processing zones and a clearance zone; the clearance zone is located between two adjacent processing zones; and at least one groove is provided in each processing zone; the clearance zone is provided with a tab groove.

[0008] Preferably, in the width direction of the current collector, the groove extends toward one edge of the current collector from the side away from the protrusion area; the protrusion extends toward the other edge of the current collector from the side away from the groove.

[0009] Preferably, in the width direction of the current collector, the processing partition is offset from the protrusion area and is disposed on the active material layer;

[0010] Alternatively, there may be a partial overlap between the processing partition and the raised area, and multiple raised points may be provided, with the groove provided between two adjacent raised points.

[0011] Preferably, the clearance area includes a tab mounting area; the number of tab mounting areas is at least two; the tab mounting area is located between two adjacent processing zones; and the tab groove is located inside the tab mounting area.

[0012] Preferably, the clearance zone further includes at least one blank area; the blank area is provided with green adhesive; the blank area is located between two adjacent processing zones;

[0013] Wherein, the length L0 of the current collector and the length L of the electrode mounting area are... 41 And the sum of the lengths L of all the aforementioned blank areas 42 The relationship between them satisfies: 0 < L 41 +L 42 ≤ L0*70%.

[0014] Preferably, the relationship between the sum of the lengths L3 of all processing zones and the length L0 of the current collector along its length direction satisfies: L0*25%≤L3≤L0*95%;

[0015] And / or, along the width direction of the current collector, the relationship between the width D5 of the processing partition and the width D0 of the current collector satisfies: D0*15%≤D5≤D0*80%.

[0016] Preferably, the relationship between the length L1 of the protruding area and the length L0 of the current collector satisfies: L0*30%≤L1≤L0*100%;

[0017] And / or, the relationship between the width D4 of the protrusion area and the width D0 of the current collector satisfies: D0*20%≤D4≤D0*80%.

[0018] Preferably, when L0*30%≤L1<L0*100%, a blank area is provided between the protruding area and the edge of the collector; and the relationship between the sum of the lengths of all the blank areas L5 and the length L0 of the collector satisfies: 0<L5≤L0*70%.

[0019] Preferably, in the width direction of the current collector, the distance D1 between the protrusion near one edge of the current collector and one edge of the current collector satisfies: 0 ≤ D1 ≤ 15 mm;

[0020] And / or, the distance D2 between the groove near the other edge of the current collector and the other edge of the current collector satisfies: 0 ≤ D2 ≤ 15 mm;

[0021] And / or, the horizontal displacement distance between the protrusion near the processing partition and the groove near the protrusion area is D3, satisfying: -5 mm ≤ D3 ≤ 5 mm.

[0022] This utility model also discloses a battery cell, including the battery cell electrode sheets described above.

[0023] This utility model also discloses a secondary battery, including the aforementioned battery cell. The beneficial effects of this utility model are that, by providing a processing zone with grooves near the tab groove side and a raised area on the non-tab groove side, it avoids the electrode sheet from avoiding the tab groove during the embossing process. Furthermore, the presence of both the raised points and grooves in the electrolyte increases the contact area between the electrolyte and the electrode sheet, thereby improving the electrolyte's capacity, wettability, and rate charge / discharge performance. In addition, by providing a groove area and a raised area in the width direction, it avoids the dust removal difficulties caused by an excessively large groove area. Attached Figure Description

[0024] The following will refer to the appendix. Figures 1-4 This section describes the features, advantages, and technical effects of exemplary embodiments of the present invention.

[0025] Figure 1 This is a schematic diagram of the structure of a battery cell electrode sheet according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a battery cell electrode sheet according to an embodiment of the present invention;

[0027] Figure 3 This is a partially enlarged view of the electrode sheet of a battery cell according to one embodiment of the present invention;

[0028] Figure 4 This is a partially enlarged view of the battery cell electrode sheet according to another embodiment of the present invention. In the figure: 11-current collector; 12-active material layer; 2-slot area; 21-processing zone; 22-avoidance area; 221-tab mounting area; 222-blank area; 201-groove; 202-tab groove; 203-green adhesive; 204-tab body; 3-protrusion area; 301-protrusion; 32-blank area. Detailed Implementation

[0029] 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 application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or multiple situations existing alone. In addition, the character " / " in this document generally indicates that the related objects before and after are in an "or" relationship.

[0033] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0034] The following is in conjunction with the appendix Figures 1-4 The present invention will be described in further detail, but this is not intended to limit the scope of the present invention.

[0035] like Figure 1As shown, in one embodiment of this utility model, the battery cell electrode sheet includes a current collector 11 and an active material layer 12 disposed on at least one surface of the current collector 11. In the width direction of the current collector 11, the active material layer 12 has a groove region 2 and a raised region 3. The raised region 3 has at least one protrusion 301. In the length direction of the current collector 11, the groove region 2 includes at least two processing zones 21 and a clearance region 22. The clearance region 22 is disposed between two adjacent processing zones 21. Each processing zone 21 has at least one groove 201. The clearance region 22 has a tab groove 202. The groove 201 is formed by laser etching or other techniques with the same effect. The protrusion 301 is formed by embossing or other techniques with the same effect. The tab 204 is connected to the tab groove 202.

[0036] The technical solution of this utility model, by setting a processing zone with a groove near the tab groove and a raised area on the non-tab groove side, can avoid the electrode sheet from avoiding the tab groove during the embossing process. Furthermore, the presence of electrolyte by both the raised points and the groove increases the contact area between the electrolyte and the electrode sheet, thereby improving the electrolyte's holding efficiency, wettability, and rate charge / discharge performance. In addition, by setting the groove area and the raised area in the width direction, the problem of dust removal difficulties caused by an excessively large groove area is avoided.

[0037] The current collector 11 includes a first surface perpendicular to the thickness direction of the electrode sheet and a second surface opposite to the first surface. The first surface has a raised area 3, and the second surface has a recessed area. The protrusions 301 of the raised area 3 contact the separator, providing support for the separator. When the electrode body expands, the protrusions 301 can still support the separator, so that there is space between the separator and the protrusions 301 to accommodate the electrolyte, preventing abnormalities such as insufficient electrolyte or poor wetting between the electrode structure and the separator due to expansion and compression.

[0038] Specifically, in some implementations, such as Figure 1 and 2 As shown, in the width direction of the current collector 11, the groove 201 extends from the side away from the protrusion 3 toward the edge of one side of the current collector 11; the protrusion 301 extends from the side away from the groove 201 toward the edge of the other side of the current collector 11. That is, only a protrusion area and a groove area are provided on one side surface of the current collector 11; thus, a liquid storage groove is created, improving electrode wettability and rate charge / discharge performance; and avoiding the disadvantages of difficult dust removal by full laser etching of the electrode, thereby improving the energy density value of the cell.

[0039] Specifically, in some implementations, such as Figure 1 , 3As shown in Figure 4, the processing partition 21 and the raised area 3 are offset on the active material layer 12; or there is a partial overlap between the processing partition 21 and the raised area 3, and multiple protrusions 301 are provided, with the groove 201 located between two adjacent protrusions 301. That is to say, during the laser etching and embossing process, the processing partition 21 and the raised area 3 can be processed separately with offsets or partially overlapped, and it is only necessary to ensure that the tab mounting area 221 is within the clearance area 22; thus, a liquid storage groove can be created, improving the wettability of the electrode and the rate charge / discharge performance; and avoiding the disadvantage of difficult dust removal during full laser etching of the electrode, thereby improving the energy density value of the battery cell.

[0040] Specifically, in some embodiments, the clearance area 22 (not shown in the figure) is the tab mounting area 221; in this case, there are two processing zones 21; the tab mounting area 221 is located between the two processing zones 21; the tab grooves 202 (arranged at equal intervals) are located inside the tab mounting area 221. At this time, only the tab mounting area 221 exists; the length L of the tab mounting area 221 is... 41 The relationship between the current collector 11 and its length L0 satisfies: 0 < L 41 ≤ L0*70%; where L can be L 41 =2%* L0, L 41 =1%* L0, L 41 =3%* L0, L 41 =4%* L0, L 41 =50%* L0, L 41 =60%* L0, L 41 =70%* L0, etc.; preferably L 41 =2%*L0. A tab mounting area of ​​a suitable length range can ensure the coverage area of ​​the groove 201, thereby improving the electrode wetting effect; and the smaller the length of the tab mounting area 221, the smaller the area occupied by the tab mounting area 221, thus the more significant the improvement in the electrode wetting effect. In other embodiments, such as... Figure 1 and 2 As shown, the clearance area 22 includes a tab mounting area 221 and at least one blank area 222; green adhesive 203 is provided in the blank area 222; multiple processing zones 21 are provided; the tab mounting area 221 is located between two adjacent processing zones 21; the blank area 222 is located between two adjacent processing zones 21. At this time, there is one tab mounting area 221 and multiple blank areas 222 with green adhesive 203; the length L0 of the current collector 11 and the length L of the tab mounting area 221 are... 41 And the sum of the lengths of all blank areas 222, L 42 The relationship between them satisfies: 0 < L 41 +L 42≤ L0*70%; where L can be L 41 +L 42 =2%* L0, L 41 +L 42 =1%* L0, L 41 +L 42 =3%* L0, L 41 +L 42 =4%* L0, L 41 +L 42 =50%* L0, L 41 +L 42 =60%* L0, L 41 +L 42 =70%* L0, etc.; preferably L 41 +L 42 =2%*L0. Further, the number of blank areas 222 is M, satisfying: 0 < M ≤ 4; that is, the number of blank areas 222 with green adhesive 203 is 0 to 4. By using a tab mounting area of ​​a certain suitable length range and multiple blank areas 222 with green adhesive 203, the coverage area of ​​the groove 201 can be guaranteed, thereby improving the electrode wetting effect; and the smaller the length of the tab mounting area and the multiple blank areas 222 with green adhesive 203, the smaller the area occupied by the tab mounting area and the multiple blank areas 222 with green adhesive 203, thus the more obvious the improvement in the electrode wetting effect.

[0041] Specifically, in some implementations, such as Figure 1 and 2 As shown, along the length direction of the current collector, the relationship between the sum of the lengths L3 of all processing sections 21 and the length L0 of the current collector 11 satisfies: L0*25%≤L3≤L0*95%; where L3 can be: L3=25%*L0, L3=30%*L0, L3=35%*L0, L3=65%*L0, L3=75%*L0, L3=95%*L0, etc., preferably L3=25%*L0. Wherein, as... Figure 2 and 3 As shown, along the width direction of the current collector, the relationship between the width D5 of the processing partition 21 and the width D0 of the current collector 11 satisfies: D0*15%≤D5≤D0*80%; where D5 can be: D5=15%*D0, D5=25%*D0, D5=35%*D0, D5=65%*D0, D5=75%*D0, D5=80%*D0, etc., preferably D5=15%*D0. That is, by using a suitable length and width, the coverage area of ​​the processing partition 21 is increased to reduce the difficulty of dust removal from the battery cell; and the improvement in electrode wetting effect is more significant.

[0042] Specifically, in some of these implementations, such as Figure 1 As shown, the bumps 301 (arranged in an array) are disposed inside the bump region 3; and the relationship between the length L1 of the bump region 3 and the length L0 of the current collector 11 satisfies: L0*30%≤L1≤L0*100%. Wherein, L1 can be L0*100%, L1=L0*90%, L1=L0*80%, L1=L0*60%, L1=L0*40%, L1=L0*30%, etc. Preferably, L1=L0*80%. When L1=L0*100%, only the bump region 3 is provided; by providing a certain space for electrode expansion during the cycling process through the bump region 3 with the largest possible area, the cycle thickness rebound of the battery cell is improved; and the electrode wettability and rate charge / discharge performance are improved. In other embodiments, such as... Figure 1 and 2 As shown, a blank area 32 is provided between the raised area 3 and the edge of the current collector 11 along the length direction of the current collector 11; and the relationship between the sum of the lengths L5 of all blank areas 32, the length L1 of the raised area 3 and the length L0 of the current collector 11 satisfies: 0 < L5 ≤ L0 * 70%; L0 * 30% ≤ L1 < L0 * 100%. Among these, L5 can be 2% * L0, L5 = 1% * L0, L5 = 3% * L0, L5 = 4% * L0, L5 = 50% * L0, L5 = 60% * L0, L5 = 70% * L0, etc.; preferably, L5 = 2% * L0. By leaving a blank area within a certain appropriate length range, the coverage area of ​​the protrusion can be guaranteed, thus reserving a certain space for the expansion of the electrode during the cycle process, improving the rebound of the cell's cycle thickness; and improving the electrode wetting effect; and the smaller the length of the tab installation area 221, the smaller the area occupied by the blank area, thus the more obvious the improvement in the electrode wetting effect.

[0043] Specifically, in some implementations, such as Figure 2 and 3 As shown, the relationship between the width D4 of the protruding area 3 and the width D0 of the current collector 11 satisfies: D0*20%≤D4≤D0*80%; where D4 can be: D4=20%*D0, D4=25%*D0, D4=35%*D0, D4=65%*D0, D4=75%*D0, D4=80%*D0, etc., preferably D4=75%*D0. That is to say, by using a suitable length and width to form the coverage area of ​​the processing partition 21, the difficulty of cell dust removal is reduced; and the improvement of the electrode wetting effect is more obvious.

[0044] Specifically, in some implementations, such as Figure 3 and 4As shown, in the width direction of the current collector 11, the distance D1 between the protrusion 301 near one edge of the current collector 11 and the edge of the current collector 11 satisfies: 0 ≤ D1 ≤ 15 mm; it can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 15 mm, etc.; preferably 1 mm. The distance D2 between the groove 201 near the other edge of the current collector 11 and the edge of the current collector 11 satisfies: 0 ≤ D2 ≤ 15 mm; it can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 15 mm, etc.; preferably 1 mm. The horizontal displacement distance D3 between the protrusion 301 near the processing partition 21 and the groove 201 near the raised area 3 satisfies: -5 mm ≤ D3 ≤ 5 mm. Wherein, when -5 mm ≤ D3 < 0 mm, there is a partial overlap between the processing partition 21 and the raised area 3. When 0mm ≤D3≤5mm, the processing zone 21 and the raised zone 3 are misaligned on the active material layer 12.

[0045] This utility model also proposes a battery cell, which includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode; the positive electrode and / or the negative electrode are battery cell electrodes, and the specific structure of the battery cell electrodes refers to the above embodiments. Since this battery cell adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0046] The positive electrode includes a positive current collector and a positive active material layer, with the active material layer coated on the surface of the current collector. The current collector can be made of aluminum, and the active material layer includes the active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer, with the active material layer coated on the surface of the current collector. The current collector can be made of copper, and the active material layer includes the active material, which can be carbon or silicon, etc. The separator can be made of PP (polypropylene) or PE (polyethylene), etc.

[0047] This utility model also proposes a secondary battery, which includes a battery cell. The specific structure of the battery cell is as described in the above embodiments. Since this secondary battery adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0048] A rechargeable battery, also known as a secondary battery or accumulator, is a battery that can be recharged after being discharged, allowing the active materials to be reactivated and reused. Utilizing the reversibility of chemical reactions, a new battery can be constructed; that is, after a chemical reaction converts into electrical energy, the electrical energy can be used to repair the chemical system, and then the chemical reaction can be converted back into electrical energy. Therefore, it is called a secondary battery (rechargeable battery). The main types of rechargeable batteries on the market include nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid (or lead-acid) batteries, lithium-ion batteries, and polymer lithium-ion batteries.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. Based on the disclosure and teachings of the above specification, those skilled in the art can also make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments described above. Any obvious improvements, substitutions, or modifications made by those skilled in the art based on this utility model are within the protection scope of this utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on this utility model.

Claims

1. An electrode tab of a battery cell, characterized by: The active material layer is arranged on at least one surface of the current collector. The active material layer is provided with a groove area and a protrusion area in the width direction of the current collector; the protrusion area is provided with at least one protrusion. In the length direction of the current collector, the groove area comprises at least two processing subareas and a blank area; the blank area is arranged between two adjacent processing subareas; and the processing subarea is provided with at least one groove; the tab groove is arranged in the blank area.

2. The electrode sheet of claim 1, wherein: In the width direction of the current collector, the groove extends away from one side end of the protrusion area and is arranged towards the edge of one side of the current collector; the protrusion extends away from one side end of the groove and is arranged towards the edge of the other side of the current collector.

3. The electrode sheet of claim 1, wherein: In the width direction of the current collector, the processing subarea is arranged on the active material layer in a staggered manner with the protrusion area. Or there is a partial overlap area between the processing subarea and the protrusion area, and the number of protrusions is multiple; the groove is arranged between two adjacent protrusions.

4. The electrode sheet of claim 1, wherein: The blank area comprises at least two tab mounting areas; the tab mounting areas are arranged between two adjacent processing subareas; and the tab groove is arranged in the tab mounting area.

5. The electrode sheet of claim 4, wherein: The blank area further comprises at least one blank area; the blank area is provided with green glue; and the blank area is arranged between two adjacent processing subareas. wherein the relationship between the length L0 of the current collector, the length L of the tab mounting region, and the sum L of the lengths of all the blank regions satisfies: 0 < L < L0*70%. 41 + L 41 + L 42 ≤ L0*70%. 42 ​ 6. The electrode sheet of claim 1, wherein: In the length direction of the current collector, the sum L3 of the lengths of all processing subareas and the length L0 of the current collector satisfy the relationship: L0*25%≤L3≤L0*95%. And / or, in the width direction of the current collector, the width D5 of the processing subarea and the width D0 of the current collector satisfy the relationship: D0*15%≤D5≤D0*80%.

7. The electrode sheet of claim 1, wherein: The length L1 of the protrusion area and the length L0 of the current collector satisfy the relationship: L0*30%≤L1≤L0*100%. And / or, the width D4 of the protrusion area and the width D0 of the current collector satisfy the relationship: D0*20%≤D4≤D0*80%.

8. The electrode sheet of claim 7, wherein: When L0*30%≤L1<L0*100%, a blank area is arranged between the protrusion area and the edge of the current collector; and the sum L5 of the lengths of all blank areas and the length L0 of the current collector satisfy the relationship: 0<L5≤L0*70%.

9. The electrode tab of any one of claims 1 to 8, wherein: In the width direction of the current collector, the distance D1 between the protrusion near the edge of one side of the current collector and the edge of one side of the current collector satisfies the relationship: 0≤D1≤15mm. And / or, the distance D2 between the groove near the edge of the other side of the current collector and the edge of the other side of the current collector satisfies the relationship: 0≤D2≤15mm. And / or, the horizontal displacement distance D3 between the protrusion near the processing subarea and the groove near the protrusion area satisfies the relationship: -5mm≤D3≤5mm.

10. An electric cell characterized by: The battery cell pole piece comprises the battery cell pole piece of any one of claims 1 to 9.

11. A secondary battery characterized by comprising: The battery cell comprises the battery cell of claim 10.

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