Roll core structure

Abstract

The utility model relates to a roll core structure. The roll core structure comprises an electrode assembly and first adhesive paper, the electrode assembly comprises a positive plate, a negative plate and a diaphragm, the positive plate, the negative plate and the diaphragm are wound, and the diaphragm is located between the adjacent positive plate and negative plate; the first adhesive paper is adhered to the corner of the negative plate, and the first adhesive paper is positioned at the innermost ring of the negative plate. According to the scheme provided by the invention, the corners of the negative plate can be prevented from being broken.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and particularly to a core structure. Background Art

[0002] Currently, protective adhesives are provided on the positive electrode sheet and the negative electrode sheet of mobile phone lithium-ion batteries. The protective adhesive is mainly used to protect the positive electrode sheet and the negative electrode sheet, preventing burrs on the positive electrode tab or the negative electrode tab, and burrs on the positive electrode current collector or the negative electrode current collector from having a negative impact on the entire core structure. However, the existing protective adhesives cannot protect the areas with relatively weak tensile strength of the positive electrode sheet or the negative electrode sheet. Affected by the rolling process of the negative electrode sheet of the lithium-ion battery, the pressure on the single-sided negative electrode material area and the junction of the single-sided and double-sided negative electrode material areas of the negative electrode sheet is relatively large, and the problem of broken pieces is likely to occur at the turning position of the negative electrode sheet corresponding to this area. Summary of the Utility Model

[0003] To solve or partially solve the problems existing in the related art, this application provides a core structure that can prevent broken pieces from occurring at the turning position of the negative electrode sheet.

[0004] On the one hand, this application provides a core structure, which includes an electrode assembly and a first adhesive tape. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the negative electrode sheet, and the separator are wound around, and the separator is located between the adjacent positive electrode sheet and the negative electrode sheet; the first adhesive tape is pasted at the turning position of the negative electrode sheet, and the first adhesive tape is located at the innermost circle of the negative electrode sheet.

[0005] Further, the negative electrode sheet includes an empty foil area and a negative electrode material area coated with negative electrode active material. The empty foil area and the negative electrode material area are connected, and the empty foil area is located at the innermost circle of the negative electrode sheet.

[0006] Further, the core structure further includes a second adhesive tape, which is pasted at the junction of the empty foil area and the negative electrode material area, and the second adhesive tape covers the junction of the empty foil area and the negative electrode material area.

[0007] Further, the first adhesive tape is located on the side of the negative electrode sheet facing the center of the electrode assembly.

[0008] Further, the core structure further includes a third adhesive tape, which is pasted at one end of the electrode assembly, and the third adhesive tape is located in the length direction of the electrode assembly.

[0009] Further, the third adhesive tape exceeds the electrode assembly in the width direction of the electrode assembly.

[0010] Further, the negative electrode sheet includes a negative electrode current collector and a negative electrode tab. The negative electrode tab is connected to the negative electrode current collector and extends outward from the negative electrode current collector. The third adhesive tape is located on a side of the electrode assembly away from the extending direction of the negative electrode tab.

[0011] Further, the thickness of the first adhesive tape is 10 - 22 μm.

[0012] Further, the first adhesive tape is made of polypropylene or acrylic.

[0013] Further, the negative electrode sheet includes a plurality of long straight segments and a plurality of curved segments. The long straight segments and the curved segments are alternately connected and extend outward from the center of the electrode assembly.

[0014] The technical solution provided by this application may include the following beneficial effects: By pasting the first adhesive tape at the turning point of the negative electrode sheet, the turning point of the negative electrode sheet is protected, the anti - fracture ability at the turning point of the negative electrode sheet is improved, ensuring that the core structure can work properly for a long time, and improving the working performance of the core structure.

[0015] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] By describing the exemplary embodiments of the present application in more detail in conjunction with the drawings, the above - mentioned 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.

[0017] Figure 1 is a schematic structural diagram of the core structure shown in the embodiment of the present application;

[0018] Figure 2 is a schematic structural diagram of the electrode assembly shown in the embodiment of the present application.

[0019] Reference numerals: positive electrode sheet 1; negative electrode sheet 2; separator 3; first adhesive tape 4; third adhesive tape 5. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will describe the embodiments of the present application in more detail with reference to the drawings. Although the 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 described 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.

[0021] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this 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, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "a plurality of" is two or more, unless otherwise specifically defined.

[0022] In the description of this 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 this 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 this application.

[0023] Unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may 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 this application can be understood according to specific circumstances.

[0024] In view of the above problems, an embodiment of this application provides a core structure that can prevent the negative electrode sheet from breaking at the turning point.

[0025] The technical solutions of the embodiments of this application will be described in detail below with reference to the drawings.

[0026] Figure 1 It is a schematic structural diagram of the core structure shown in the embodiment of this application.

[0027] See Figure 1 , the core structure includes an electrode assembly and a first adhesive tape 4. The electrode assembly includes a positive electrode sheet 1, a negative electrode sheet 2, and a separator 3. The positive electrode sheet 1, the negative electrode sheet 2, and the separator 3 are wound to form a runway-shaped electrode assembly. The separator 3 is located between the adjacent positive electrode sheet 1 and negative electrode sheet 2, and the separator 3 can separate the positive electrode sheet 1 and the negative electrode sheet 2 to prevent the positive electrode sheet 1 and the negative electrode sheet 2 from short-circuiting.

[0028] The first adhesive tape 4 is pasted at the turning point of the negative electrode sheet 2, and the first adhesive tape 4 is located at the innermost circle of the negative electrode sheet 2. Taking one end of the negative electrode sheet 2 at the center of the electrode assembly as the starting point, the first adhesive tape 4 is located at the second turning point of the negative electrode sheet 2.

[0029] In this application, by pasting the first adhesive tape 4 at the turning point of the negative electrode sheet 2, the turning point of the negative electrode sheet 2 is protected, the anti-fragmentation ability of the turning point of the negative electrode sheet 2 is improved, it is ensured that the core structure can work normally for a long time, and the working performance of the core structure is improved.

[0030] The positive electrode sheet 1 includes a blank area and a positive electrode material area coated with positive electrode active material. The blank area and the positive electrode material area are connected. Specifically, the positive electrode sheet 1 includes a copper foil and a positive electrode active material layer. The positive electrode active material can be coated on the surface of the copper foil. The copper foil and the positive electrode active material layer form the positive electrode material area, and the copper foil without the positive electrode active material coated forms the blank area. The negative electrode sheet 2 includes an empty foil area and a negative electrode material area coated with negative electrode active material. The empty foil area and the negative electrode material area are connected. The empty foil area is located at the innermost circle of the negative electrode sheet. Specifically, the negative electrode sheet 2 includes an aluminum foil and a negative electrode active material layer. The negative electrode active material can be coated on the surface of the aluminum foil. The aluminum foil and the negative electrode active material layer form the negative electrode material area, and the aluminum foil without the negative electrode active material coated forms the empty foil area. One side of the aluminum foil coated with the negative electrode active material is the single-sided area, and both opposite sides of the aluminum foil coated with the negative electrode active material are the double-sided area. The first adhesive tape 4 is pasted on the empty foil area. Since the empty foil area is relatively thin compared to the negative electrode material area and the empty foil area is located at the center of the electrode assembly, the negative electrode sheet 2 is prone to fragmentation at the empty foil area. There is a turning point of the negative electrode sheet 2 in the empty foil area. Therefore, by pasting the first adhesive tape 4 on the empty area and the first adhesive tape 4 can cover the turning point of the negative electrode sheet 2, the structural strength of the empty foil area can be effectively enhanced, and fragmentation of the empty foil area can be prevented.

[0031] In some embodiments, the first adhesive tape 4 is located on the side of the negative electrode sheet 2 facing the center of the electrode assembly. With this design, it can be avoided that the first adhesive tape 4 occupies too much space, thereby indirectly improving the energy density of the core structure. In some embodiments, the first adhesive tape 4 can be located on the side of the negative electrode sheet 2 facing away from the center of the electrode assembly. With this design, the anti-fragmentation ability of the turning point of the negative electrode sheet 2 can be further improved.

[0032] In some embodiments, the core structure further includes a second adhesive tape. The second adhesive tape is pasted at the junction of the empty foil area and the negative electrode material area, and the second adhesive tape covers the junction of the empty foil area and the negative electrode material area. Since the empty foil area is relatively thin compared to the negative electrode material area, the negative electrode sheet 2 is prone to fragmentation due to uneven thickness at the junction of the empty foil area and the negative electrode material area. Therefore, by pasting the second adhesive tape at the junction of the empty foil area and the negative electrode material area, the problem of uneven thickness generated at the junction of the empty foil area and the negative electrode material area can be improved, the structural strength of the junction of the empty foil area and the negative electrode material area can be enhanced, and fragmentation at the junction of the empty foil area and the negative electrode material area can be prevented.

[0033] Figure 2 It is a schematic structural diagram of the electrode assembly shown in the embodiments of the present application.

[0034] Refer to Figure 1 and Figure 2 , in some embodiments, the core structure further includes a third adhesive tape 5. The third adhesive tape 5 is pasted at one end of the electrode assembly. The cross-section of the electrode assembly is waist-shaped. The third adhesive tape 5 is located in the length direction of the waist-shaped cross-section of the electrode assembly, and the third adhesive tape 5 is located on the outer side of the electrode assembly. Since the overall machine test of the mobile phone lithium-ion battery is relatively strict and there are defects in the structural design of the mobile phone, a clearance groove needs to be opened in the slot for installing the lithium-ion battery. The clearance groove is on one side of the lithium-ion battery, resulting in different local impact forces on the lithium-ion battery during the test. For the place where the impact is greater, it is easy to cause deformation at the corresponding position of the electrode assembly. Therefore, by pasting the third adhesive tape 5 on the electrode assembly, it can protect the corresponding position of the electrode assembly where the clearance groove is located and prevent the electrode assembly from deforming and affecting the normal use of the lithium-ion battery. The third adhesive tape 5 exceeds the electrode assembly in the width direction of the electrode assembly to ensure that the third adhesive tape 5 can completely cover one end of the electrode assembly, so as to ensure that the electrode assembly will not be broken during the overall machine test.

[0035] The negative electrode sheet 2 includes a negative electrode current collector and a negative electrode tab. The negative electrode tab is connected to the negative electrode current collector. The negative electrode tab extends outward from the negative electrode current collector. The third adhesive tape 5 is located on the side of the electrode assembly away from the extending direction of the negative electrode tab. Since the clearance groove of the mobile phone is located on the side close to the bottom of the slot of the lithium-ion battery and the clearance groove is on the side away from the negative electrode tab, by setting the third adhesive tape 5 on the side of the electrode assembly away from the extending direction of the negative electrode tab, the third adhesive tape 5 can be aligned with the clearance groove, and the third adhesive tape 5 does not need to wrap the entire end of the electrode assembly, saving the use of the third adhesive tape 5, reducing the production cost, and also reducing the occupied space of the core structure.

[0036] Refer to Figure 1 , in some embodiments, the thickness of the first adhesive tape 4 is 10-22 μm. Preferably, the thickness of the first adhesive tape 4 is 10 μm. The first adhesive tape 4 with this thickness can reduce the space occupied by the first adhesive tape 4 on the premise of ensuring that the electrode assembly can be protected, so that the electrode assembly has more space and indirectly improves the energy density of the core structure. The first adhesive tape 4 is made of polypropylene or acrylic.

[0037] In some embodiments, the core structure is an even-fold structure. The negative electrode sheet 2 includes a plurality of long straight segments and a plurality of curved segments. The long straight segments and the curved segments are alternately connected and extend outward from the center of the electrode assembly. The thickness of one side of the electrode structure is relatively large, and the thickness of the other side of the electrode structure is relatively small. Taking one end of the negative electrode sheet 2 at the center of the electrode assembly as the starting point, the second turning point of the negative electrode sheet 2 is located on the side with a relatively small thickness of the electrode structure. By adding the first adhesive tape 4 at the second turning point, the thickness of the electrode assembly side is balanced, the flatness of the core structure is improved, and the cycle failure caused by uneven thickness and unbalanced pressure during formation is avoided.

[0038] The solutions of the present application have been described in detail above with reference to the accompanying drawings. In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not described in detail in a certain embodiment, reference may 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 essential to the present application. In addition, it can be understood that the steps in the method embodiments of the present application can be adjusted, combined, and deleted according to actual needs, and the modules in the device embodiments of the present application can be combined, divided, and deleted according to actual needs.

[0039] The various embodiments of the present application have been described above. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art in the technical field without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other ordinary skill in the art in the technical field to understand the disclosed embodiments.

Claims

1. A core structure, characterized in that, It includes an electrode assembly and a first adhesive tape. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet, the negative electrode sheet, and the separator are wound. The separator is located between the adjacent positive electrode sheet and negative electrode sheet. The first adhesive tape is pasted at the turning of the negative electrode sheet, and the first adhesive tape is located at the innermost circle of the negative electrode sheet.

2. The core structure according to claim 1, wherein: The negative electrode sheet includes an empty foil area and a negative electrode material area coated with a negative electrode active material. The empty foil area and the negative electrode material area are connected, and the empty foil area is located at the innermost circle of the negative electrode sheet.

3. The core structure according to claim 2, characterized in that: It further includes a second adhesive tape. The second adhesive tape is pasted at the junction of the empty foil area and the negative electrode material area, and the second adhesive tape covers the junction of the empty foil area and the negative electrode material area.

4. The core structure according to claim 1, characterized in that: The first adhesive tape is located on the side of the negative electrode sheet facing the center of the electrode assembly.

5. The core structure according to claim 1, characterized in that: It further includes a third adhesive tape. The third adhesive tape is pasted at one end of the electrode assembly, and the third adhesive tape is located in the length direction of the electrode assembly.

6. The core structure according to claim 5, characterized in that: The third adhesive tape extends beyond the electrode assembly in the width direction of the electrode assembly.

7. The core structure according to claim 5, characterized in that: The negative electrode sheet includes a negative electrode current collector and a negative electrode tab. The negative electrode tab is connected to the negative electrode current collector. The negative electrode tab extends outward from the negative electrode current collector. The third adhesive tape is located on the side of the electrode assembly away from the extending direction of the negative electrode tab.

8. The core structure according to claim 1, characterized in that: The thickness of the first adhesive tape is 10 to 22 μm.

9. The core structure according to claim 1, wherein: The first adhesive tape is made of polypropylene or acrylic.

10. The core structure according to claim 1, characterized in that: The negative electrode sheet includes a plurality of long straight segments and a plurality of curved segments. The long straight segments and the curved segments are alternately connected and extend outward from the center of the electrode assembly.

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