Negative pole piece of laminated battery and laminated battery

Abstract

The utility model relates to a negative pole piece of a laminated battery and the laminated battery. The negative pole piece of the laminated battery comprises a negative current collector, a negative active material coating is arranged on the surface of the negative current collector, thickening parts are arranged on the two opposite sides of the negative active material coating, the thickening parts extend along the edge of the negative active material coating, and the thickness of the thickening parts is larger than that of the negative active material coating. The thickness of the negative electrode active material coating at the thickening parts is greater than the thickness of the part between the two thickening parts, and the negative electrode active material coating forms a limiting groove for placing a positive electrode plate between the two opposite thickening parts. According to the scheme provided by the invention, dislocation of the positive pole piece and the negative pole piece can be avoided, and the alignment degree is ensured.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a negative electrode sheet and a stacked battery of a stacked battery. Background Art

[0002] The lithium-ion battery stacking technology is a battery manufacturing process. This technology stacks components such as positive electrode sheets, negative electrode sheets, and separators together in a certain order and manner to form the basic structure of the battery cell. Stacked batteries are widely used in the field of power batteries, including electric vehicles, energy storage systems, etc.

[0003] In related technologies, during the stacking process of the electrode sheets of the stacked battery cell, the positive electrode sheet and the negative electrode sheet are prone to shift and have poor alignment. This will cause abnormal coating of the negative electrode sheet on the positive electrode sheet, affecting the manufacturing yield and quality of the battery. When using the battery cell with poor alignment during subsequent cyclic use, lithium deposition is likely to occur at the abnormal part, causing safety accidents. Summary of the Utility Model

[0004] To solve or partially solve the problems existing in related technologies, this application provides a negative electrode sheet and a stacked battery of a stacked battery, which can avoid misalignment between the positive electrode sheet and the negative electrode sheet and ensure alignment.

[0005] In the first aspect of this application, a negative electrode sheet of a stacked battery is provided, including: a negative current collector, a negative active material coating is provided on the surface of the negative current collector, thickened parts are provided on two opposite sides of the negative active material coating, the thickened parts extend along the edge of the negative active material coating, the thickness of the negative active material coating at the thickened parts is greater than the thickness of the part between the two thickened parts, and a limiting groove for placing the positive electrode sheet is formed between two opposite thickened parts of the negative active material coating.

[0006] Further, the thickened parts extend along the length edges of the negative current collector.

[0007] Further, negative active material coatings are provided on both opposite surfaces of the negative current collector.

[0008] Further, the cross-section of the negative electrode sheet is in an I shape.

[0009] Further, the negative current collector is made of copper foil or aluminum foil.

[0010] In the second aspect of this application, a stacked battery is provided, including: a positive electrode sheet and the negative electrode sheet as described in any one of the above, and the positive electrode sheet is located in the limiting groove.

[0011] Further, the positive electrode sheet includes a positive current collector, a positive active material coating is provided on the surface of the positive current collector, and the positive current collector is made of aluminum foil.

[0012] Further, the thickness by which the thickened portion protrudes from the bottom of the limiting groove is 1 / 5 to 1 / 4 of the thickness of the positive electrode plate.

[0013] Further, the above-mentioned laminated battery further includes: a separator, and the negative electrode plate, the separator, the positive electrode plate, the separator, the positive electrode plate, the separator, and the negative electrode plate are sequentially stacked in an alternating manner to form an electrode core.

[0014] Further, the above-mentioned laminated battery further includes a housing and an electrolyte, and both the electrode core and the electrolyte are located inside the housing.

[0015] The technical solution provided by this application may include the following beneficial effects: By providing thickened portions on opposite sides of the negative electrode active material coating, the thickened portions extend along the edges of the negative electrode active material coating, and the thickness of the negative electrode active material coating at the thickened portions is greater than the thickness of the portion between the two thickened portions, so that a limiting groove for placing the positive electrode plate is formed between the two opposite thickened portions of the negative electrode active material coating. During the process of stacking the electrode plates, the positive electrode plate is restricted by the limiting groove and will not shift relative to the negative electrode plate, which can avoid the misalignment of the positive electrode plate and the negative electrode plate and ensure the alignment degree.

[0016] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. Description of the Drawings

[0017] By describing the exemplary embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. Among them, in the exemplary embodiments of the present application, the same reference numerals generally represent the same components.

[0018] Figure 1 is a schematic cross-sectional view of the laminated battery shown in the embodiment of the present application;

[0019] Figure 2 is a schematic structural view of the positive electrode plate and the negative electrode plate shown in the embodiment of the present application;

[0020] Figure 3 is another schematic structural view of the positive electrode plate and the negative electrode plate shown in the embodiment of the present application.

[0021] Reference Signs:

[0022] 1. Negative electrode plate; 11. Negative current collector; 12. Negative electrode active material coating; 122. Thickened portion; 13. Limiting groove; 2. Positive electrode plate; 3. Separator. Detailed Embodiments

[0023] Embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0024] It should be understood that although the terms "first", "second", "third", etc. may be used in the present application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0025] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0026] Unless otherwise clearly specified and defined, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0027] In the related art, during the process of stacking the electrode sheets of a laminated battery cell, the positive electrode sheet and the negative electrode sheet are prone to shift and have poor alignment, which will cause abnormal coating of the negative electrode sheet on the positive electrode sheet, affecting the manufacturing yield and quality of the battery. When using the battery cell with poor alignment during subsequent cyclic use, lithium deposition is likely to occur at the abnormal position, resulting in safety accidents.

[0028] In view of the above problems, the embodiments of the present application provide a laminated battery that can avoid misalignment between the positive electrode sheet and the negative electrode sheet and ensure alignment.

[0029] The technical solutions of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] As Figures 1 to 3 shown, an embodiment of the present application provides a laminated battery, including a positive electrode plate 2 and a negative electrode plate 1. Among them, the negative electrode plate 1 includes a negative current collector 11, and a negative active material coating 12 is provided on the surface of the negative current collector 11. Thickened portions 122 are provided on opposite sides of the negative active material coating 12. The thickened portions 122 extend along the edge of the negative active material coating 12. The thickness of the negative active material coating 12 at the thickened portions 122 is greater than the thickness of the portion between the two thickened portions 122. The negative active material coating 12 forms a limiting groove 13 for placing the positive electrode plate 2 between the two opposite thickened portions 122.

[0031] By providing thickened portions 122 on opposite sides of the negative active material coating 12, the thickened portions 122 extend along the edge of the negative active material coating 12, and the thickness of the negative active material coating 12 at the thickened portions 122 is greater than the thickness of the portion between the two thickened portions 122, so that the negative active material coating 12 forms a limiting groove 13 for placing the positive electrode plate 2 between the two opposite thickened portions 122. During the process of stacking the electrode plates, the positive electrode plate 2 is restricted by the limiting groove 13 and will not shift relative to the negative electrode plate 1, which can avoid misalignment between the positive electrode plate 2 and the negative electrode plate 1 and insufficient coating of the negative electrode plate 1 on the positive electrode plate 2, thereby ensuring the alignment degree.

[0032] Specifically, when coating the negative active material coating 12, the coating thickness of the opposite two side edges of the negative active material coating 12 is thickened to form the thickened portions 122. The shape of the thickened portions 122 can be strip-shaped, and the cross-section can be rectangular, so that the edge of the negative active material coating 12 forms a convex edge. Setting the thickened portions 122 at the edge of the negative active material coating 12 can improve the CB value of the battery cell without changing the size, improve the cycling performance, and reduce the problem of lithium deposition during cycling due to the CB value. The CB value (cell Balance) is the margin of the negative electrode capacity exceeding the positive electrode capacity on the opposite side within the same stage and under the same conditions. CB value = gram capacity of negative active material × negative surface density × ratio of negative active material content ÷ (gram capacity of positive active material × positive surface density × ratio of positive active material content).

[0033] In some embodiments, the thickened portions 122 extend along the length edge of the negative current collector 11. Specifically, the edge of the negative active material coating 12 is aligned with the edge of the negative current collector 11, and the thickened portions 122 are provided at the length edge of the negative current collector 11, while the width edge of the negative current collector 11 does not need to be provided with thickened portions 122. The tab of the battery cell can be connected to the negative current collector 11 from the width edge of the negative current collector 11.

[0034] In some embodiments, negative active material coatings 12 are provided on opposite sides of the negative current collector 11 , so that positive electrode sheets 2 can be provided on both sides of the negative electrode sheet 1 , and the positive and negative electrode sheets are laminated and hot-pressed.

[0035] In some embodiments, Figure 1 and Figure 3 As shown, the cross-section of the negative electrode sheet 1 is in an I-shape. Specifically, the thickened portions 122 on both sides of the negative electrode collector 11 are perpendicular to the negative electrode collector 11, so that the negative electrode sheet 1 is in an I-shape as a whole. In this way, the two sides of the negative electrode sheet 1 are respectively provided with limiting grooves 13 to limit the positive electrode sheets 2 on both sides.

[0036] Optionally, the negative electrode current collector 11 is made of copper foil or aluminum foil.

[0037] In some embodiments, the positive electrode plate 2 includes a positive electrode current collector, a positive electrode active material coating is provided on the surface of the positive electrode current collector, and the positive electrode current collector can be made of aluminum foil.

[0038] In some embodiments, the thickness of the thickened portion 122 protruding from the bottom of the limiting groove 13 is 1 / 5 to 1 / 4 of the thickness of the positive electrode plate 2, that is, the size of the portion of the thickened portion 122 higher than the negative electrode active material coating 12 is 1 / 5 to 1 / 4 of the thickness of the positive electrode plate 2, which can ensure that the positive electrode plate 2 is limited without affecting the performance of the battery.

[0039] In some embodiments, Figure 1 As shown, the laminated battery also includes a diaphragm 3, and the negative electrode sheet 1, the diaphragm 3, the positive electrode sheet 2, the diaphragm 3, the positive electrode sheet 2, the diaphragm 3, and the negative electrode sheet 1 are alternately stacked in sequence to form a battery cell, that is, the battery cell is arranged in a cycle in the order of negative electrode sheet 1, diaphragm 3, positive electrode sheet 2, diaphragm 3, positive electrode sheet 2, diaphragm 3, and negative electrode sheet 1.

[0040] In some embodiments, the laminated battery further includes a shell and an electrolyte, the battery core and the electrolyte are both located in the shell, the battery core is heat-pressed, then placed in the shell, and then sealed, injected with electrolyte, and activated to form a laminated battery. The shell can be made of aluminum-plastic film, stainless steel, aluminum, aluminum alloy, or nickel-plated steel.

[0041] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of the various embodiments have their own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Those skilled in the art should also be aware that the actions and modules involved in the specification are not necessarily required for the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in order, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0042] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. The negative electrode plate of a laminated battery, characterized in that, Comprising: A negative current collector, on the surface of which there is a negative active material coating. On two opposite sides of the negative active material coating, there are thickened parts, the thickened parts extend along the edge of the negative active material coating, the thickness of the negative active material coating at the thickened parts is greater than the thickness of the part between the two thickened parts, and a limiting groove for placing a positive electrode plate is formed between the two opposite thickened parts of the negative active material coating.

2. The negative electrode plate of the laminated battery according to claim 1, characterized in that: The thickened part extends along the length edge of the negative current collector.

3. The negative electrode plate of the laminated battery according to claim 1, characterized in that: Negative active material coatings are provided on both opposite side surfaces of the negative current collector.

4. The negative electrode plate of the laminated battery according to claim 1, characterized in that: The cross-section of the negative electrode plate is in an I shape.

5. The negative electrode plate of the laminated battery according to claim 1, characterized in that: The negative current collector is made of copper foil or aluminum foil.

6. A stacked battery, characterized in that, Comprising: A positive electrode plate and the negative electrode plate according to any one of claims 1-5, the positive electrode plate is located in the limiting groove.

7. The laminated battery according to claim 6, characterized in that: The positive electrode plate includes a positive current collector, on the surface of which there is a positive active material coating, and the positive current collector is made of aluminum foil.

8. The laminated battery according to claim 6, characterized in that: The thickness by which the thickened part protrudes from the bottom of the limiting groove is 1 / 5 to 1 / 4 of the thickness of the positive electrode plate.

9. The laminated battery according to claim 6, wherein Further comprising: A separator, and the negative electrode plate, the separator, the positive electrode plate, the separator, the positive electrode plate, the separator, and the negative electrode plate are alternately stacked in sequence to form an electric core.

10. The laminated battery according to claim 9, characterized in that: Further comprising a housing and an electrolyte, and the electric core and the electrolyte are both located inside the housing.

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