A winding core structure for increasing the internal space of a cylindrical power battery

Abstract

The present invention provides a winding core structure for increasing the internal space of a cylindrical power battery, and relates to the technical field of cylindrical power batteries. The present invention includes a positive electrode sheet, a negative electrode sheet, a liquid swelling tape, and a diaphragm; wherein the positive electrode sheet is continuously coated, including a positive electrode coating area and a positive electrode tab foil blank area; the negative electrode sheet is segmentedly coated, including a negative electrode coating area and a negative electrode tab foil blank area; the positive electrode tab foil is aluminum foil, and the negative electrode tab foil is copper foil; the diaphragm is placed between the positive electrode sheet and the negative electrode sheet, the positive electrode tab foil blank area and the negative electrode tab foil blank area are perpendicular to each other, and the positive electrode sheet and the negative electrode sheet are wound into a winding core; the outer periphery of the winding core is wound with the negative electrode tab foil for several turns, and the inner part of the winding core is wound with the liquid swelling tape; this structure saves the folding height space of the negative electrode tab of the winding core, so that the height of the winding core body inside the battery cell is increased, the volume utilization rate inside the battery cell is improved, and the energy density of the battery cell product is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cylindrical power batteries, and in particular to a winding core structure for increasing the internal space of a cylindrical power battery. Background Art

[0002] Existing cylindrical power batteries usually consist of three parts: a cover plate, a winding core, and a shell. The cover plate mainly integrates the positive output terminal of the cylindrical battery, insulating plastic, and the cover plate body. The winding core mainly consists of the winding core body and the output terminals of the winding core - the positive pole ear and the negative pole ear. The positive output pole is combined with the positive pole ear of the winding core by laser penetration welding, and the battery shell is also combined with the negative pole ear of the winding core by laser penetration welding. Finally, the battery cover body shell is also combined together by laser welding to form a sealed space.

[0003] At present, in order to meet the demand for excessive current of cylindrical power batteries, most battery cell manufacturers have adopted a winding scheme in which the positive and negative pole tabs of the core are respectively on both sides of the core body. In this case, the space for the core body inside the battery cell needs to be reduced by the folded height of the two tabs in the height direction. The height of the core body = the total height space inside the battery cell (H) - the folded height of the positive pole tabs of the core (h1) - the folded height of the negative pole tabs of the core (h2). When the total height space inside the battery cell is constant, due to the necessary space loss of h1 and h2, it is difficult to improve the volume utilization rate inside the battery cell, that is, it is difficult to increase the height of the core body inside the battery cell, and then it is difficult to improve the energy density of the battery cell product, and the product loses competitiveness. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the present invention provides a winding core structure for increasing the internal space of a cylindrical power battery.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A winding core structure for increasing the internal space of a cylindrical power battery, specifically comprising a positive electrode sheet, a negative electrode sheet, a liquid absorption swelling tape, and a diaphragm;

[0007] The positive electrode sheet is coated continuously, including a positive electrode coating area and a positive electrode tab foil blank area;

[0008] The negative electrode sheet is coated in sections, including a negative electrode coating area and a negative electrode tab foil blank area;

[0009] The positive electrode tab foil is aluminum foil, and the negative electrode tab foil is copper foil;

[0010] The separator is placed between the positive electrode sheet and the negative electrode sheet, the blank area of ​​the positive electrode tab foil and the blank area of ​​the negative electrode tab foil are perpendicular to each other, and the positive electrode sheet and the negative electrode sheet are wound into a winding core;

[0011] The outer periphery of the winding core is wound with the negative electrode tab foil for several turns, the inner part of the winding core is wound with the liquid absorption swelling tape, and the outer negative electrode tab foil is connected to the battery shell;

[0012] The start and end points of the liquid absorption and swelling tape are consistent with the start and end points of the outer negative electrode tab foil.

[0013] Beneficial effects of the present invention:

[0014] The present invention provides a winding core structure for increasing the internal space of a cylindrical power battery, eliminating the space for folding the negative electrode tab of the winding core, that is, increasing the height of the winding core body inside the battery cell by h2, thereby improving the volume utilization rate inside the battery cell, thereby increasing the energy density of the battery cell product and improving the product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the positive electrode sheet according to a specific embodiment of the present invention;

[0016] In the figure, 1-the blank area of ​​the positive electrode tab foil, 2-the positive electrode coating area;

[0017] Figure 2 It is a schematic diagram of the structure of the negative electrode sheet according to a specific embodiment of the present invention;

[0018] In the figure, 3-negative electrode coating area, 4-negative electrode tab foil blank area;

[0019] Figure 3 It is a schematic diagram of a negative electrode sheet of a conventional solution of a specific implementation method provided by the present invention;

[0020] Figure 4 It is a winding schematic diagram of a specific embodiment of the present invention;

[0021] Among them, 5-diaphragm, 6-positive and negative electrode sheet coating overlap area, 7-negative electrode sheet coating super positive electrode sheet coating area;

[0022] Figure 5 It is a winding schematic diagram of a conventional solution of a specific implementation mode provided by the present invention;

[0023] Figure 6 Schematic diagram comparing the traditional solution of the specific implementation mode provided by the present invention and the winding core of the present invention;

[0024] Figure 7 is a schematic diagram of a winding core according to a specific embodiment of the present invention;

[0025] Among them, 8-liquid swelling tape, 9-positive electrode sheet (containing active material), 10-negative electrode sheet (containing active material), 11-several turns of negative electrode tab foil outside the winding core;

[0026] Figure 8 It is a schematic diagram of the expansion of the winding core after liquid injection according to a specific embodiment of the present invention;

[0027] Fig. 9 It is a schematic diagram comparing the traditional solution of the specific implementation mode provided by the present invention and the winding core of the present invention. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] A winding core structure for increasing the internal space of a cylindrical power battery, specifically comprising a positive electrode sheet, a negative electrode sheet, and a liquid absorption expansion tape;

[0030] The positive electrode sheet is coated continuously, including a positive electrode coating area and a positive electrode tab foil blank area, such as Figure 1 As shown;

[0031] The negative electrode sheet is coated in sections, including a negative electrode coating area and a negative electrode tab foil blank area, such as Figure 2 As shown;

[0032] The positive electrode tab foil is aluminum foil, and the negative electrode tab foil is copper foil;

[0033] like Figure 3 Schematic diagram of the negative electrode sheet of the conventional scheme of the specific implementation mode provided by the present invention. In the conventional scheme, the negative electrode sheet is the same as the positive electrode sheet and is continuously coated.

[0034] The separator is placed between the positive electrode sheet and the negative electrode sheet, the blank area of ​​the positive electrode tab foil and the blank area of ​​the negative electrode tab foil are perpendicular to each other, and the positive electrode sheet and the negative electrode sheet are wound into a winding core;

[0035] like Figure 4 The figure shows a winding schematic diagram; the blank area of ​​the positive electrode tab foil is axial, and the blank area of ​​the negative electrode tab foil is radial. Figure 5 It is a schematic diagram of the winding of the traditional scheme; in the traditional scheme, the blank area of ​​the positive electrode tab foil and the blank area of ​​the negative electrode tab foil are parallel to each other. Based on the above, a comparative analysis can be made, such as Figure 6 : This solution can save the space h2 for the negative electrode tab to be folded in the height direction of the winding core;

[0036] The outer periphery of the winding core is wound with the negative electrode tab foil for several turns, that is, the outer side of the original winding core is wrapped with one or more layers of copper foil, and the inner side of the winding core is wound with the liquid absorption expansion tape, that is, when the battery cell is injected with liquid, the expansion tape can drive the outermost copper foil of the winding core to expand radially, and finally contact with the shell, and the outer negative electrode tab foil is connected to the shell of the battery;

[0037] The starting and ending points of the liquid absorption swelling tape are consistent with the starting and ending points of the outer negative electrode tab foil;

[0038] like Figure 7 FIG. 1 is a schematic diagram of a winding core according to a specific embodiment of the present invention; Figure 8 As shown, the direction indicated by the arrow is the expansion direction of the core. After the battery cell is filled with liquid, the expansion tape drives the outermost copper foil of the core to expand radially, and finally contacts the shell, so that the shell is connected to the negative electrode of the core.

[0039] Based on the above, we can make a comparative analysis, such as Fig. 9 :The solution in this paper can save the space h2 for the negative electrode tab to be folded in the height direction of the winding core;

[0040] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) to form a technical solution.

Claims

1. A winding core structure for increasing the internal space of a cylindrical power battery, characterized in that: Including positive electrode sheet, negative electrode sheet, liquid absorption swelling tape, and diaphragm; The positive electrode sheet is coated continuously, including a positive electrode coating area and a positive electrode tab foil blank area; The negative electrode sheet is coated in sections, including a negative electrode coating area and a negative electrode tab foil blank area; The separator is placed between the positive electrode sheet and the negative electrode sheet, the blank area of ​​the positive electrode tab foil and the blank area of ​​the negative electrode tab foil are perpendicular to each other, and the positive electrode sheet and the negative electrode sheet are wound into a winding core; The outer periphery of the winding core is wound with the negative electrode tab foil for several turns, the liquid absorption swelling tape is wound inside the winding core, and the outer negative electrode tab foil is connected to the battery shell.

2. A winding core structure for increasing the internal space of a cylindrical power battery according to claim 1, characterized in that: The positive electrode tab foil is aluminum foil, and the negative electrode tab foil is copper foil.

3. A winding core structure for increasing the internal space of a cylindrical power battery according to claim 1, characterized in that: The start and end points of the liquid absorption and swelling tape are consistent with the start and end points of the outer negative electrode tab foil.

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