Battery winding core structure and flexible package battery

Abstract

The utility model relates to a battery roll core structure and a flexible package battery. The battery roll core structure comprises a positive pole piece, a negative pole piece and a diaphragm, the end, located in the center of the battery roll core structure, of the positive pole piece is a positive pole piece inner end, the end, located in the center of the battery roll core structure, of the negative pole piece is a negative pole piece inner end, and the positive pole piece inner end and the negative pole piece inner end are arranged in a central symmetry mode; the positive pole piece comprises a positive current collector, the positive current collector is provided with a positive active coating, the positive pole piece comprises a first positive folding part, the first positive folding part is arranged in a single fabric mode, the negative pole piece comprises a negative current collector, the negative current collector is provided with a negative active coating, the negative pole piece comprises a first negative folding part, and the first negative folding part is arranged in a single fabric mode. The first negative electrode folding part is a single fabric, and the first positive electrode folding part and the first negative electrode folding part are oppositely arranged. According to the scheme provided by the invention, the risks of bending, folding and powder falling of the single-fabric area at the head of the negative pole piece in the winding process can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soft package lithium ion battery, and particularly relates to a battery roll core structure and a soft package battery. BACKGROUND

[0002] The roll core structure of the soft package lithium ion battery is mainly divided into two types of winding type and laminated type. The winding type cell is generally formed by winding negative electrode sheet, separator and positive electrode sheet in sequence, and has the advantages of high production efficiency and good consistency of lithium ion battery.

[0003] With the increase of the energy density of the battery, the thickness of the negative electrode current collector used in the soft package lithium ion battery is continuously thinned, and the compaction density of the negative electrode sheet is continuously improved, which continuously increases the risk of bending and folding of the single surface material area of the head of the negative electrode sheet and the risk of powder falling during the winding process. CONTENT OF THE UTILITY MODEL

[0004] To solve or partially solve the problems in the related art, the present application provides a battery roll core structure and a soft package battery, which can reduce the risk of bending and folding of the single surface material area of the head of the negative electrode sheet and the risk of powder falling during the winding process.

[0005] The first aspect of the present application provides a battery roll core structure, comprising: a positive electrode sheet, a negative electrode sheet and a separator arranged between the positive electrode sheet and the negative electrode sheet;

[0006] The end of the positive electrode sheet located at the center of the battery roll core structure is a positive sheet inner end, the end of the negative electrode sheet located at the center of the battery roll core structure is a negative sheet inner end, and the positive sheet inner end and the negative sheet inner end are arranged in a central symmetry;

[0007] The positive electrode sheet comprises a positive current collector, the two opposite surfaces of the positive current collector are provided with positive active coating, the positive electrode sheet comprises a positive first folding part located at the center of the battery roll core structure, the positive first folding part is provided with single surface material, the negative electrode sheet comprises a negative current collector, the two opposite surfaces of the negative current collector are provided with negative active coating, the negative electrode sheet comprises a negative first folding part located at the center of the battery roll core structure, the negative first folding part is provided with single surface material, and the positive first folding part and the negative first folding part are arranged oppositely.

[0008] Further, one side of the positive first folding part, which is not provided with the positive active coating, is arranged towards the negative first folding part, and one side of the negative first folding part, which is not provided with the negative active coating, is arranged towards the positive first folding part.

[0009] Further, one side of the positive first folding part, which is not provided with the positive active coating, is arranged away from the negative first folding part, and one side of the negative first folding part, which is not provided with the negative active coating, is arranged away from the positive first folding part.

[0010] Further, the positive electrode tab is arranged on the positive electrode tab, and the negative electrode tab is arranged on the negative electrode tab.

[0011] Further, the positive electrode tab is arranged on the positive electrode tab, and the negative electrode tab is arranged on the negative electrode tab.

[0012] Further, the positive electrode tab is arranged on the positive electrode tab, and the negative electrode tab is arranged on the negative electrode tab.

[0013] Further, the positive electrode tab is made of aluminum sheet, and the negative electrode tab is made of nickel sheet or copper-nickel plated material.

[0014] Further, the positive current collector is made of aluminum foil, and the negative current collector is made of copper foil.

[0015] The second aspect of the present application provides a soft package battery, comprising: a package shell, an electrolyte and the battery roll structure as described in any one of the above, wherein the electrolyte and the battery roll structure are both located in the package shell.

[0016] Further, the package shell is made of aluminum-plastic composite film.

[0017] The technical solution provided by the present application can include the following beneficial effects: by arranging the inner end of the positive electrode tab located at the center of the battery roll structure and the inner end of the negative electrode tab located at the center of the battery roll structure in a central symmetric manner, and arranging the positive first fold part and the negative first fold part in an opposite manner, the positive electrode tab and the negative electrode tab can be wound in a central symmetric manner during winding, and the positive first fold part and the negative first fold part are both arranged in a single-sided material, which makes the structure of the center part of the battery roll structure symmetric, thereby balancing the internal structure of the battery roll structure, making the internal positive electrode tab and the negative electrode tab more evenly distributed, and the internal tension of the battery roll structure can be well balanced, thereby reducing the risk of bending and folding of the single-sided material area (i.e. the negative first fold part) at the head of the negative electrode tab and the risk of powder falling during winding.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the several views, and in which:

[0020] Figure 1is a sectional view of a battery roll structure shown in the related art;

[0021] Figure 2 is a sectional view of a battery roll structure shown in the related art;

[0022] Figure 3 is Figure 2 is a partial enlarged view of the center of the battery roll structure shown.

[0023] Reference Signs:

[0024] 1 - positive electrode sheet, 11 - inner end of positive electrode sheet, 12 - positive current collector, 13 - positive active coating, 14 - first folding part of positive electrode, 2 - negative electrode sheet, 21 - inner end of negative electrode sheet, 22 - negative current collector, 23 - negative active coating, 24 - first folding part of negative electrode, 3 - separator, 4 - positive electrode tab, 5 - negative electrode tab, 6 - insulating tape. DETAILED DESCRIPTION

[0025] Embodiments of the present application will be described in more detail by referring to the attached drawings. Although embodiments of the present application are shown in the drawings, it should be understood that the present application can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0026] It should be understood that although the terms "first", "second", "third", etc. can be used herein to describe various information, these information should not be limited by these terms. These terms are only used to distinguish information of the same type from each other. For example, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information without departing from the scope of the present application. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0027] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be understood as limiting the present application.

[0028] Unless otherwise defined, the terms "mounting", "connected", "connecting", "fixed", and "fixedly" are not to be construed as being necessarily limited to a direct connection, but can be an indirect connection via another member, and can be mechanically or electrically connected, and can be directly connected or indirectly connected via a member, or can be a relationship between two elements in which one element is in the other element, or a mutual interaction relationship between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0029] Figure 1 is a sectional view of a battery roll structure shown in the related art. As shown in Figure 1 , the battery roll structure includes a positive electrode sheet 1, a negative electrode sheet 2, and a separator 3, which are collectively wound. Among them, the first fold and the second fold at the center of the battery roll structure of the negative electrode sheet 2 are single-sided material areas, and the negative electrode sheet 2 is coated with an active coating layer only on one side in the single-sided material area, and the other side opposite to it is not coated with an active coating layer. The end of the positive electrode sheet 1 at the center of the battery roll structure is a double-sided material area. The ends of the positive electrode sheet 1 and the negative electrode sheet 2 in the inner circle of the battery roll structure are wound in the same direction, and the single-sided material area at the end of the negative electrode sheet 2 is prone to bending and folding during the winding process due to the difference in rolling of the A and B surfaces, thereby causing the negative electrode sheet 2 to drop powder and other abnormalities, reducing the production yield and increasing the cost. In addition, for a battery with a small length-width ratio and a large width size, as the length of the single-sided material area at the end of the negative electrode sheet 2 increases, the risk of bending, folding, and dropping of the single-sided material area at the end of the negative electrode sheet 2 during winding also increases. In addition, with the continuous improvement of battery energy density, thinner negative electrode current collectors and larger negative electrode compaction density are usually used, which reduces the rigidity of the negative electrode sheet 2 and increases the deformation difference of the single-sided material area, thereby increasing the risk of bending and folding of the single-sided material area at the end of the negative electrode sheet 2.

[0030] To solve the above problems, the present application provides a battery roll structure and a soft-packaged battery, which can solve the problem of the winding type soft-packaged battery with a small length-width ratio or a thin negative electrode current collector, in which the single-sided material area at the end of the negative electrode sheet 2 is prone to folding and thus dropping powder during the winding process, causing the battery appearance to have protrusions and poor K value, thereby reducing the production yield and increasing the cost during the production process.

[0031] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0032] Figure 2 is a sectional view of a battery roll structure shown in the related art. As shown in Figure 3 is Figure 2 is a partial enlarged view of the center of the battery roll structure.

[0033] As Figure 2 andFigure 3 As shown, the battery roll core structure provided by the embodiments of the present application includes a positive electrode sheet 1, a negative electrode sheet 2, and a separator 3 arranged between the positive electrode sheet 1 and the negative electrode sheet 2. The positive electrode sheet 1, the negative electrode sheet 2, and the separator 3 are arranged in a roll shape.

[0034] The end of the positive electrode sheet 1 at the center of the battery roll core structure is a positive electrode inner end 11, and the end of the negative electrode sheet 2 at the center of the battery roll core structure is a negative electrode inner end 21. The positive electrode inner end 11 and the negative electrode inner end 21 are arranged in a central symmetry. The symmetry center of the positive electrode inner end 11 and the negative electrode inner end 21 is located at the center point of the battery roll core structure, that is, the intersection of the two diagonal lines in the cross-sectional view of the battery roll core structure.

[0035] The positive electrode sheet 1 includes a positive current collector 12, and the two opposite surfaces of the positive current collector 12 are provided with positive active coating layers 13. The positive electrode sheet 1 includes a positive electrode first folding part 14 located at the center of the battery roll core structure, and the positive electrode first folding part 14 is arranged in a single-sided material. The negative electrode sheet 2 includes a negative current collector 22, and the two opposite surfaces of the negative current collector 22 are provided with negative active coating layers 23. The negative electrode sheet 2 includes a negative electrode first folding part 24 located at the center of the battery roll core structure, and the negative electrode first folding part 24 is arranged in a single-sided material. The positive electrode first folding part 14 and the negative electrode first folding part 24 are arranged oppositely. The positive electrode first folding part 14 is the innermost part of the positive electrode sheet 1 in the battery roll core structure, and is arranged in a horizontal direction in the drawing. The negative electrode first folding part 24 is the innermost part of the negative electrode sheet 2 in the battery roll core structure, and is arranged in a horizontal direction in the drawing.

[0036] By arranging the positive electrode inner end 11 of the positive electrode sheet 1 at the center of the battery roll core structure and the negative electrode inner end 21 of the negative electrode sheet 2 at the center of the battery roll core structure in a central symmetry, and by arranging the positive electrode first folding part 14 and the negative electrode first folding part 24 oppositely, the positive electrode sheet 1 and the negative electrode sheet 2 can be wound in a central symmetry during winding. In addition, the positive electrode first folding part 14 and the negative electrode first folding part 24 are arranged in a single-sided material. This arrangement balances the structure of the central part of the battery roll core structure, balances the internal structure of the battery roll core structure, and makes the positive electrode sheet 1 and the negative electrode sheet 2 more evenly distributed. In this way, the internal tension of the battery roll core structure can be well balanced, thereby reducing the risk of bending and folding and powder falling in the single-sided material area (i.e., the negative electrode first folding part 24) of the head of the negative electrode sheet 2 during winding. The problem of the soft-pack battery with a small length-width ratio or a thin negative current collector, i.e., the single-sided material area of the end of the negative electrode sheet 2 is easily folded during winding, thereby causing the negative electrode sheet 2 to fall powder, resulting in a convex point defect in the appearance of the battery and an increase in K value, and leading to a decrease in process yield and an increase in cost during production, is solved.

[0037] In some embodiments, as shown in FIG. 1, the battery roll core structure includes a positive electrode sheet 1, a negative electrode sheet 2, and a separator 3 arranged between the positive electrode sheet 1 and the negative electrode sheet 2. Figure 2 and Figure 3As shown, the side of the positive electrode first fold portion 14, on which the positive electrode active coating 13 is not arranged, faces the negative electrode first fold portion 24, and the side of the negative electrode first fold portion 24, on which the negative electrode active coating 23 is not arranged, faces the positive electrode first fold portion 14. That is, at the positive electrode first fold portion 14, the positive electrode active coating 13 is arranged on the side surface of the positive current collector 12 close to the negative electrode first fold portion 24, and the positive electrode active coating 13 is not arranged on the side surface of the positive current collector 12 away from the negative electrode first fold portion 24; at the negative electrode first fold portion 24, the negative electrode active coating 23 is arranged on the side surface of the negative current collector 22 close to the positive electrode first fold portion 14, and the negative electrode active coating 23 is not arranged on the side surface of the negative current collector 22 away from the positive electrode first fold portion 14, so that the positive electrode first fold portion 14 and the negative electrode first fold portion 24 are further symmetrically arranged.

[0038] In addition, the positive electrode first fold portion 14 is arranged opposite to the negative electrode first fold portion 24, and forms an inner waistcoat. In destructive tests such as weight impact or needle puncture test, the short circuit mode of the inner anode-cathode in the common roll structure is converted into the short circuit mode of the positive current collector 12-negative current collector 22 (copper foil-aluminum foil), and the short circuit mode of the positive current collector 12 and the negative current collector 22 has good heat conduction performance, heat is not accumulated, the probability of thermal runaway is greatly reduced, and the safety performance is higher.

[0039] In some embodiments, the side of the positive electrode first fold portion 14, on which the positive electrode active coating 13 is not arranged, faces away from the negative electrode first fold portion 24, and the side of the negative electrode first fold portion 24, on which the negative electrode active coating 23 is not arranged, faces away from the positive electrode first fold portion 14.

[0040] In some embodiments, as shown in FIG. 1, the positive electrode tab 4 is arranged on the positive electrode tab 1, and the negative electrode tab 5 is arranged on the negative electrode tab 2. Figure 2 As shown, the positive electrode tab 4 is arranged on the positive electrode tab 1, and the negative electrode tab 5 is arranged on the negative electrode tab 2. Specifically, the positive electrode tab 4 and the negative electrode tab 5 are connected with the positive electrode tab 1 and the negative electrode tab 2 by laser welding.

[0041] In some embodiments, as shown in FIG. 1, the positive electrode tab 4 is arranged on the positive electrode tab 1, and the negative electrode tab 5 is arranged on the negative electrode tab 2. Specifically, the positive electrode tab 4 and the negative electrode tab 5 are connected with the positive electrode tab 1 and the negative electrode tab 2 by laser welding. Figure 2 As shown, the positive electrode tab 4 is arranged on the positive electrode tab 1, and the negative electrode tab 5 is arranged on the negative electrode tab 2. Specifically, the positive electrode tab 4 and the negative electrode tab 5 are connected with the positive electrode tab 1 and the negative electrode tab 2 by laser welding.

[0042] In some embodiments, as shown in FIG. 1, the positive electrode tab 4 is arranged on the positive electrode tab 1, and the negative electrode tab 5 is arranged on the negative electrode tab 2. Specifically, the positive electrode tab 4 and the negative electrode tab 5 are connected with the positive electrode tab 1 and the negative electrode tab 2 by laser welding. Figure 2 Figure 2As shown, the negative tab 2 on the opposite side of the positive tab 4 and the positive tab 1 on the opposite side of the negative tab 5 are both provided with an insulating tape 6. Specifically, the negative tab 2 on the opposite side of the positive tab 4, i.e. the two circles of negative tabs 2 adjacent to the positive tab 4, is provided with the insulating tape 6 to prevent the positive tab 4 from short-circuiting with the adjacent negative tab 2 after piercing the separator 3. The positive tab 1 on the opposite side of the negative tab 5, i.e. the two circles of positive tabs 1 adjacent to the negative tab 5, is provided with the insulating tape 6 to prevent the negative tab 5 from short-circuiting with the adjacent positive tab 1 after piercing the separator 3.

[0043] In some embodiments, the positive tab 4 is made of an aluminum sheet, and the negative tab 5 is made of a nickel sheet or a copper-nickel plated material.

[0044] In some embodiments, the positive current collector 12 is made of an aluminum foil, and the negative current collector 22 is made of a copper foil.

[0045] The application also provides a soft-packaged battery, which comprises a packaging shell, an electrolyte, and a battery core structure as described in any of the above embodiments. The electrolyte and the battery core structure are both located in the packaging shell.

[0046] In some embodiments, the packaging shell is made of an aluminum-plastic composite film.

[0047] The application has been described in detail with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments. It should also be appreciated by those skilled in the art that the actions and modules described in the specification are not necessarily required by the application. In addition, it should be understood that the steps in the method embodiments of the application can be adjusted, combined and reduced in sequence according to actual needs, and the modules in the device embodiments of the application can be combined, divided and reduced according to actual needs.

[0048] The above has described various embodiments of the application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles, practical applications or improvements to the technology in the market, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A battery jelly-roll structure, characterized by, Comprising: a positive electrode tab, a negative electrode tab, and a separator disposed between the positive electrode tab and the negative electrode tab; one end of the positive electrode tab at the center of the battery core structure is a positive tab inner end, one end of the negative electrode tab at the center of the battery core structure is a negative tab inner end, and the positive tab inner end and the negative tab inner end are centrally symmetrically arranged; the positive electrode tab comprises a positive current collector, the opposite surfaces of the positive current collector are provided with positive active coating, the positive electrode tab comprises a positive first folding part at the center of the battery core structure, the positive first folding part is provided as a single-sided material, the negative electrode tab comprises a negative current collector, the opposite surfaces of the negative current collector are provided with negative active coating, the negative electrode tab comprises a negative first folding part at the center of the battery core structure, the negative first folding part is provided as a single-sided material, and the positive first folding part and the negative first folding part are oppositely arranged.

2. The battery core structure according to claim 1, wherein: one side of the positive first folding part without the positive active coating is arranged towards the negative first folding part, and one side of the negative first folding part without the negative active coating is arranged towards the positive first folding part.

3. The battery core structure according to claim 1, wherein: one side of the positive first folding part without the positive active coating is arranged away from the negative first folding part, and one side of the negative first folding part without the negative active coating is arranged away from the positive first folding part.

4. The battery core structure according to claim 1, wherein: a positive tab is arranged on the positive electrode tab, and a negative tab is arranged on the negative electrode tab.

5. The battery core structure according to claim 4, wherein: insulating adhesive tape is arranged on the positive electrode tab on the opposite sides of the positive tab and on the negative electrode tab on the opposite sides of the negative tab.

6. The battery core structure according to claim 5, wherein: the insulating adhesive tape is arranged on the negative electrode tab on the opposite sides of the positive tab and on the positive electrode tab on the opposite sides of the negative tab.

7. The battery core structure according to claim 4, wherein: the positive tab is made of aluminum sheet, and the negative tab is made of nickel sheet or copper-nickel-plated material.

8. The battery core structure according to claim 1, wherein: the positive current collector is made of aluminum foil, and the negative current collector is made of copper foil.

9. A soft-packaged battery characterized by comprising: Comprising: a packaging shell, an electrolyte, and the battery core structure according to any one of claims 1 to 8, wherein the electrolyte and the battery core structure are arranged in the packaging shell.

10. The soft-pack battery of claim 9, wherein: the packaging shell is made of aluminum-plastic composite film.

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