Cathode plate, battery and electric device

Abstract

The utility model belongs to the technical field of battery production and manufacturing, and particularly relates to a cathode plate, which comprises a current collector and active material layers coated on two surfaces of the current collector at intervals, a priming coat is arranged between the current collector and the active material layers, the area of the cathode plate corresponding to a primary bending corner forming a battery cell is a regulation and control area, and the primary bending corner is a secondary bending corner. A groove is formed in the portion, located in the regulation and control area, of the bottom coating layer, the groove penetrates through the bottom coating layer from the surface of the current collector, the groove comprises a first groove, and the portion, located in the regulation and control area, of the cathode piece slitting area falls in the groove position area of the first groove. According to the utility model, the grooves are formed in the bottom coating layer, so that the pulling force of one-fold corners can be shared by the grooves when the cathode sheet is wound, and the possibility of belt breakage is reduced. In addition, the utility model also discloses a battery comprising the cathode plate and an electric device.

Description

Technical Field

[0001] The utility model belongs to the technical field of battery production and manufacturing, and specifically relates to a cathode sheet, a battery and an electrical device. Background Art

[0002] Nowadays, with the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium-ion batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, which provides a broad space for the application and development of lithium-ion batteries.

[0003] Among them, the battery cell can be divided into a laminated battery cell and a wound battery cell. In the field of power lithium batteries, the winding process is more common. However, the cathode sheet with high compaction and thin aluminum foil undercoating is easy to break during the winding or cyclic expansion process due to its high compaction, thin foil material, and small first folding corner, resulting in a decrease in the electrode sheet quality rate or abnormal battery cell capacity. Therefore, it is urgent to propose a new technical solution to solve the above problems. Utility Model Content

[0004] One of the purposes of the utility model is to provide a cathode sheet in view of the deficiencies of the prior art, which provides a groove in the bottom coating so that when the cathode sheet is wound, the tension at a folded corner is shared by the groove, thereby reducing the occurrence of tape breakage.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A cathode sheet, comprising a current collector and active material layers coated on both sides of the current collector at intervals, a primer layer is provided between the current collector and the active material layer, and the area of ​​the cathode sheet corresponding to the primary bending corner of the battery cell is a control area;

[0007] The bottom coating layer in the control area is provided with a groove, and the groove runs through the bottom coating layer from the surface of the current collector. The groove includes a first groove, and the cathode sheet cutting area in the control area falls within the groove area of ​​the first groove.

[0008] As an improvement of the cathode sheet described in the utility model, in the width direction of the cathode sheet, the first groove has a first side and a second side parallel to the long side of the cathode sheet, the cathode sheet cutting area is located at the two edges of the cathode sheet, and the cutting line of the cathode sheet cutting area is located between the first side and the second side.

[0009] In practical applications, the setting of the groove can reduce the overall thickness of the cathode sheet located in the control area, the force applied during rolling is relatively small, the foil is less stretched and damaged, the tensile strength is improved, and the possibility of tape breakage is reduced; the groove can share the tension at the corner when the cathode sheet is wound, further reducing the possibility of tape breakage; at the same time, once the edge of the cathode sheet is broken after slitting, the tape is most likely to break. Providing the first groove in the slitting area, i.e., the edge of the cathode sheet, can improve the problem of tape breakage caused by the break at the edge of the cathode sheet.

[0010] As an improvement of the cathode plate described in the utility model, the groove also includes a second groove, which is located between two adjacent first grooves. At least one second groove is provided, and the second groove has a supplementary effect, increasing the total area of ​​the groove and being able to share more corner tension.

[0011] As an improvement of the cathode sheet of the utility model, in the length direction of the cathode sheet, the length of the groove is set to 1mm-50mm.

[0012] As an improvement of the cathode sheet of the utility model, in the width direction, the width of the groove is set to 0.5mm-10mm. The regulation of the groove size can reduce the possibility of cathode sheet breakage while ensuring the basic functions of the base coating layer bonding and conductivity.

[0013] As an improvement of the cathode sheet of the utility model, the active material layer includes a first material layer and a second material layer, and the length of the first material layer in the length direction is greater than the length of the second material layer in the length direction.

[0014] As an improvement of the cathode sheet described in the utility model, the first material layer located in the control area is a thinning layer, and the first material layer also includes a coating layer interconnected with the thinning layer, the thickness of the thinning layer is D1, the thickness of the coating layer is D2, and D1 and D2 satisfy the relationship: D2-D1=a, a is the adjustment constant, 2um≤a≤50um, further reducing the overall thickness of the cathode sheet located in the control area and reducing the possibility of cathode sheet breakage.

[0015] As an improvement of the cathode sheet described in the utility model, a side of the cathode sheet away from the winding center of the battery cell is a away surface, and the away surface located in the control area is pasted with adhesive tape, which can share the corner pressure and further reduce the possibility of cathode sheet breakage.

[0016] The second object of the present utility model is to provide a battery, comprising the cathode sheet as described above.

[0017] The third object of the present utility model is to provide an electrical device comprising the battery as described above.

[0018] The beneficial effect of the utility model is that the cathode sheet of the utility model includes a current collector and an active material layer coated on both sides of the current collector at intervals, a primer layer is arranged between the current collector and the active material layer, the area of ​​the cathode sheet corresponding to the first bending corner where the battery cell is formed is a control area, and the primer layer located in the control area is provided with a groove, and the groove penetrates the primer layer from the surface of the current collector, and the groove includes a first groove, and the first groove is arranged corresponding to the cutting area of ​​the cathode sheet. The utility model arranges a groove in the primer layer, so that when the cathode sheet is wound, the tension of the first bending corner is shared by the groove, while reducing the thickness of the cathode sheet at the first bending corner, and can improve the edge crack phenomenon of the cathode sheet, thereby reducing the possibility of belt breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

[0020] Figure 1 This is one of the cross-sectional views of the present invention.

[0021] Figure 2 This is the second cross-sectional view of the present utility model.

[0022] Figure 3 It is a structural schematic diagram of the utility model.

[0023] Figure 4 Schematic diagram of the structure of the uncut cathode sheet.

[0024] The reference numerals are described as follows:

[0025] 1-current collector;

[0026] 2-active material layer; 21-first material layer; 211-thinning layer; 212-coating layer; 22-second material layer;

[0027] 3-base coating; 31-groove; 311-first groove; 3111-first side; 3112-second side; 312-second groove;

[0028] 4-Adhesive tape;

[0029] 5-Pole ear;

[0030] 6-Pole ear slot;

[0031] X-width direction; Y-length direction. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific implementation methods and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0034] Reference to "embodiment" in this application means that a particular feature, structure or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0036] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0037] The development of battery technology must consider many design factors at the same time, such as performance parameters such as energy density, cycle life, discharge capacity, charge and discharge rate, and battery safety. However, the cathode sheets in current batteries are easily broken during winding or cycle expansion due to high compaction, thin foil, and small first folding corner, resulting in decreased electrode sheet quality or abnormal cell capacity. To solve the above problems, the inventors have created grooves in the primer to reduce the occurrence of broken strips.

[0038] The following is combined with Figures 1 to 4 The utility model is further described in detail with specific implementation modes, but is not intended to limit the utility model.

[0039] like Figure 1 As shown, a cathode sheet comprises a current collector 1 and active material layers 2 coated on both sides of the current collector 1 at intervals, a primer layer 3 is arranged between the current collector 1 and the active material layer 2, the area of ​​the cathode sheet corresponding to the primary bending corner where the battery cell is formed is a control area, the cathode sheet is provided with a cutting area, and the cutting area is located at the edges of both sides of the cathode sheet; the primer layer 3 located in the control area is provided with a groove 31, and the groove 31 penetrates the primer layer 3 from the surface of the current collector 1.

[0040] In this embodiment, the cathode sheet is provided with a tab groove 6, which penetrates the active material layer 2 and the base coating layer 3. The tab 5 located in the tab groove 6 is connected to the current collector 1. The tab 5 is used for electric energy transmission to ensure the realization of the basic charging and discharging functions of the battery formed by the cathode sheet.

[0041] In this embodiment, the material used for the base coating 3 is at least one of lithium iron phosphate, PVDF and SP. The base coating 3 can improve the conductivity and adhesion between the current collector 1 and the active material layer 2, and can also enhance the protection of the current collector 1, thereby improving the performance of the cathode sheet.

[0042] Specifically, in the length direction Y of the cathode sheet, the length of the groove 31 is set to 1mm-50mm; in the width direction X, the width of the groove 31 is set to 0.5mm-10mm. The size of the groove 31 can reduce the possibility of cathode segment breakage while ensuring the basic functions of adhesion and conductivity of the base coating 3.

[0043] like Figure 3 As shown, the groove 31 includes a first groove 311 and a second groove 322. The cathode sheet cutting area located in the control area falls within the groove area of ​​the first groove 311. Two first grooves 311 are provided. The second groove 312 is located between two adjacent first grooves 311. At least one second groove 312 is provided. The second groove 312 has a supplementary effect, increasing the total area of ​​the groove 31 so that it can share more corner tension.

[0044] To better illustrate the positional relationship between the first groove 311 and the cutting area, as shown in FIG. Figure 4 As shown, Figure 4 The dotted line in the figure is the cutting line of the cutting area. Figure 4 The middle groove 31 is located below the active material layer 2, and the groove 31 cannot be seen in the actual object. In the width direction X, the first groove 311 has a first side 3111 and a second side 3112 parallel to the long side of the cathode sheet. The cutting area is located at the edges of both sides of the cathode sheet, and the cutting line of the cutting area is located between the first side 3111 and the second side 3112, which can prevent the edge of the cathode sheet from being broken when the cutting knife is cutting, thereby further preventing the cathode sheet from breaking.

[0045] In practical applications, the setting of the groove 31 can reduce the overall thickness of the cathode sheet located in the control area, the force applied during rolling is relatively small, the foil is less stretched and damaged, the tensile strength is improved, and the possibility of tape breakage is reduced; the groove 31 can share the tension at the corner when the cathode sheet is wound, further reducing the possibility of tape breakage.

[0046] In some other embodiments, Figure 2 As shown, the active material layer 2 includes a first material layer 21 and a second material layer 22, the length of the first material layer 21 in the length direction Y is greater than the length of the second material layer 22 in the length direction Y, the first material layer 21 located in the control area is a thinning layer 211, and the first material layer 21 also includes a coating layer 212 interconnected with the thinning layer 211, the thickness of the thinning layer 211 is D1, the thickness of the coating layer 212 is D2, D1 and D2 satisfy the relationship: D2-D1=a, a is the adjustment constant, 2um≤a≤50um, further reducing the overall thickness of the cathode sheet located in the control area and reducing the possibility of cathode sheet breakage.

[0047] In some other embodiments, Figure 2 As shown, the side of the cathode sheet away from the winding center of the battery cell is the away surface, and the away surface located in the control area is pasted with adhesive tape 4. The adhesive tape 4 and the groove 31 are arranged correspondingly along the thickness direction of the cathode sheet. The adhesive tape 4 can share the corner pressure and further reduce the possibility of the cathode sheet being broken.

[0048] Battery

[0049] A battery comprises an anode sheet, a pole sheet as described above and a separator, wherein the separator is located between the anode sheet and the cathode sheet, and the battery can be a lithium ion battery, a sodium ion battery, a magnesium ion battery, etc.

[0050] Electrical devices

[0051] An electrical device, comprising the above-mentioned battery, wherein the electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0052] According to the disclosure and teaching of the above description, the technicians in the field of the utility model can also change and modify the above implementation. Therefore, the utility model is not limited to the above specific implementation, and any obvious improvement, replacement or modification made by the technicians in this field on the basis of the utility model belongs to the protection scope of the utility model. In addition, although some specific terms are used in this specification, these terms are only for the convenience of explanation and do not constitute any limitation to the utility model.

Claims

1. A cathode sheet, characterized in that: It comprises a current collector (1) and active material layers (2) coated at intervals on both sides of the current collector (1), a primer layer (3) is arranged between the current collector (1) and the active material layer (2), and the area of ​​the cathode sheet corresponding to the primary bending corner of the battery cell is the control area; The base coating (3) located in the control zone is provided with a groove (31), the groove (31) penetrates the base coating (3) from the surface of the current collector (1), the groove (31) includes a first groove (311), and the control zone has a cathode sheet cutting area falling within the groove area of ​​the first groove (311).

2. The cathode sheet according to claim 1, characterized in that: In the width direction (X) of the cathode sheet, the first groove (311) has a first side (3111) and a second side (3112) parallel to the long side of the cathode sheet, the cathode sheet cutting area is located at the two edges of the cathode sheet, and the cutting line of the cathode sheet cutting area is located between the first side (3111) and the second side (3112).

3. The cathode sheet according to claim 1, characterized in that: The groove (31) further comprises a second groove (312), wherein the second groove (312) is located between two adjacent first grooves (311), and at least one second groove (312) is provided.

4. The cathode sheet according to claim 1, characterized in that: In the length direction (Y) of the cathode sheet, the length of the groove (31) is set to 1mm-50mm.

5. The cathode sheet according to claim 2, characterized in that: In the width direction (X), the width of the groove (31) is set to 0.5mm-10mm.

6. The cathode sheet according to claim 4, characterized in that: The active material layer (2) comprises a first material layer (21) and a second material layer (22), wherein the length of the first material layer (21) in the length direction (Y) is greater than the length of the second material layer (22) in the length direction (Y).

7. The cathode sheet according to claim 6, characterized in that: The first material layer (21) located in the control area is a skived layer (211), and the first material layer (21) further comprises a coating layer (212) interconnected with the skived layer (211), the thickness of the skived layer (211) is D1, the thickness of the coating layer (212) is D2, and D1 and D2 satisfy the relationship: D2-D1=a, a is an adjustment constant, 2um≤a≤50um.

8. The cathode sheet according to claim 1, characterized in that: The side of the cathode sheet that is away from the winding center of the cathode sheet forming the battery core is a away surface, and the away surface located in the control area is pasted with adhesive tape (4).

9. A battery, characterized in that: The invention comprises an anode sheet, a cathode sheet as claimed in any one of claims 1 to 8, and a separator, wherein the separator is located between the anode sheet and the cathode sheet.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 9.

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