Battery cell structure and secondary battery

Abstract

The utility model provides a kind of electric core structure, including electric core;Electric core includes roll core structure, roll core structure extension part;Roll core structure includes positive sheet, negative sheet and separator;Positive sheet is composed of positive active material layer, positive current collector;Negative sheet is composed of negative active material layer, negative current collector;Roll core structure extension part is formed by the positive current collector, negative current collector and separator of roll core structure and outward extension winding;The positive current collector of roll core structure extension part is equipped with positive lug;The negative current collector of roll core structure extension part is equipped with negative lug;Positive lug and negative lug are arranged in a certain angle staggered;Positive current collector end is located outside negative current collector end, or, positive current collector end is located inside negative current collector end, and positive current collector end exceeds negative current collector end or positive current collector end is located between negative lug and negative current collector end;The utility model provides a kind of secondary battery including above-mentioned a kind of electric core structure, electric core shell and electrolyte.

Description

Technical Field

[0001] This utility model relates to the technical field of wound batteries, and in particular to a cell structure and a secondary battery. Background Technology

[0002] Traditional soft-pack button-wound batteries have requirements for the angle of the tabs and the winding direction to meet the required installation position and usage requirements. Generally, at the end of the battery cell, the negative electrode is located outside the positive electrode. The positive tab on the positive electrode and the negative tab on the negative electrode meet certain angle requirements. The end of the positive electrode is not only located inside the end of the negative electrode, but also does not exceed the position of the negative tab.

[0003] Examples of such wound batteries include: Chinese invention patent application CN201711448449, titled "A Wound Battery Cell, a Cell Winding Method, and a Wound Battery." Typically, the positive electrode tab of this type of wound battery cell extends slightly beyond the positive current collector, and the negative electrode tab extends slightly beyond the negative current collector. (This is to allow for a small distance before welding the positive or negative electrode tabs.)

[0004] Currently, the above-mentioned wound battery has the following defects: during the battery charge and discharge cycle, when the positive electrode expands, the cutting force at the end of the positive electrode is large, which can easily cause the negative electrode to break, and eventually cause the connection between the negative electrode and the negative electrode tab to break, resulting in battery failure. Utility Model Content

[0005] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a cell structure and a secondary battery to solve the problem that the expansion of the positive electrode sheet causes the negative electrode sheet to break and ultimately leads to battery failure.

[0006] To achieve the above objectives, this utility model is accomplished through the following two aspects:

[0007] Firstly, this utility model provides a battery cell structure.

[0008] It includes battery cells;

[0009] The battery cell includes a wound core structure and a wound core structure extension disposed on the outer ring of the wound core structure;

[0010] The wound core structure includes a positive electrode sheet, a negative electrode sheet, and a separator, wherein the separator separates the positive electrode sheet and the negative electrode sheet;

[0011] The positive electrode plate is composed of a positive electrode active material layer and a positive electrode current collector;

[0012] The negative electrode sheet is composed of a negative electrode active material layer and a negative electrode current collector;

[0013] The core structure extension is formed by the positive current collector, negative current collector and separator of the core structure extending outward and being wound respectively.

[0014] The positive electrode current collector of the core structure extension is provided with a positive electrode tab;

[0015] The negative electrode current collector of the core structure extension is provided with a negative electrode tab;

[0016] In the winding direction of the extension of the core structure, the positive electrode tab and the negative electrode tab are offset at a certain angle;

[0017] In the winding direction of the extension of the core structure, the positive current collector end is located outside the negative current collector end, or the positive current collector end is located inside the negative current collector end;

[0018] When the positive current collector end is located inside the negative current collector end, the positive current collector end extends beyond the negative current collector end; or, the positive current collector end is located between the negative current collector tab and the negative current collector end.

[0019] Preferably, the positive electrode tab is fixed to the positive current collector by welding, and the negative electrode tab is fixed to the negative current collector by welding.

[0020] Preferably, in the winding direction of the core structure extension, the clockwise angle formed between the line connecting the center point of the core structure extension and the positive electrode tab, and the line connecting the center point of the core structure extension and the negative electrode tab, is set at a certain angle.

[0021] Preferably, in the winding direction of the core structure extension, the clockwise angle formed between the line connecting the center point of the core structure extension and the positive electrode tab, and the line connecting the center point of the core structure extension and the negative electrode tab, is in the range of 80-180 degrees.

[0022] Preferably, both the positive current collector and the negative current collector comprise one or more of natural graphite and artificial graphite.

[0023] Preferably, a positive electrode protective adhesive paper is provided on the outside of the positive electrode tab.

[0024] Preferably, the negative electrode tab is provided with a negative electrode protective adhesive paper on its outer side.

[0025] Secondly, this utility model provides a secondary battery, including a cell structure, a cell casing, and an electrolyte as described in the first aspect, wherein the cell structure is installed inside the cell casing, and the electrolyte is filled between the cell structure and the cell casing.

[0026] Preferably, the battery cell casing is made of aluminum.

[0027] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0028] 1. This utility model discloses a cell structure and a secondary battery. When the positive and negative tabs are offset at a certain angle, the problem of negative electrode breakage due to positive electrode expansion, ultimately leading to battery failure, is solved through the following three methods:

[0029] A. In the winding direction of the extension of the core structure, the end of the positive current collector is located outside the end of the negative current collector. At this time, during the battery charge and discharge cycle, the positive electrode sheet expands and will not affect the breakage of the negative electrode sheet.

[0030] B. In the winding direction of the extension of the core structure, the end of the positive current collector is located inside the end of the negative current collector, and the end of the positive current collector extends beyond the end of the negative current collector. At this time, during the battery charge and discharge cycle, the positive electrode sheet expands, which will not affect the breakage of the negative electrode sheet.

[0031] C. In the winding direction of the extension of the core structure, the end of the positive current collector is located inside the end of the negative current collector, and the end of the positive current collector is located between the end of the negative current collector and the negative tab. At this time, the position between the negative tab and the negative current collector is an inactive area. During the battery charge and discharge cycle, even if the positive electrode sheet expands and cuts off the position between the negative tab and the negative current collector, cutting off this inactive area will not cause current flow, nor will it affect the normal power supply of the negative tab, and will ultimately not affect battery failure.

[0032] 2. In summary, the cell structure and secondary battery provided by this utility model effectively avoid the situation where the negative electrode breaks due to the expansion of the positive electrode, ultimately leading to battery failure. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a cross-sectional schematic diagram of a cell structure and a secondary battery provided in an embodiment of the present invention;

[0035] Figure 2 This is a cross-sectional schematic diagram of the core structure provided in an embodiment of this utility model;

[0036] Figure 3This is a cross-sectional schematic diagram of a second embodiment of a cell structure and a secondary battery provided by this utility model;

[0037] Figure 4 This is a cross-sectional schematic diagram of a second embodiment of a cell structure and a secondary battery provided by this utility model.

[0038] The diagram includes:

[0039] 1. Battery cell; 11. Core structure; 12. Core structure extension; 2. Positive electrode sheet; 21. Positive current collector; 22. Positive active material layer; 23. Positive tab; 24. Positive protective film; 3. Negative electrode sheet; 31. Negative current collector; 32. Negative active material layer; 33. Negative tab; 34. Negative protective film; 4. Separator. Detailed Implementation

[0040] The technical solution of this embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiment is one embodiment of the present invention, and not all embodiments thereof. Based on this embodiment of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Please see Figures 1 to 4 An embodiment of this utility model provides a battery cell structure, which includes a battery cell 1;

[0042] The battery cell 1 includes a wound core structure 11 and a wound core structure extension 12 disposed on the outer ring of the wound core structure 11;

[0043] The core structure 11 includes a positive electrode 2, a negative electrode 3, and a separator 4, wherein the separator 4 separates the positive electrode 2 and the negative electrode 3.

[0044] The positive electrode 2 consists of a positive electrode active material layer 22 and a positive electrode current collector 21;

[0045] The negative electrode 3 is composed of a negative electrode active material layer 32 and a negative electrode current collector 31;

[0046] The core structure extension 12 is formed by the positive current collector 21, the negative current collector 31 and the separator 4 of the core structure 11 extending outward and being wound respectively.

[0047] A positive electrode tab 23 is provided on the positive electrode current collector 21 of the core structure extension 12, and a positive electrode protective adhesive paper 24 is provided on the outside of the positive electrode tab 23;

[0048] The negative electrode current collector 31 of the core structure extension 12 is provided with a negative electrode ear 33, and a negative electrode protective adhesive paper 34 is provided on the outside of the negative electrode ear 33.

[0049] In the winding direction of the core structure extension 12, the positive electrode tab 23 and the negative electrode tab 33 are staggered at a certain angle to meet the required installation position requirements.

[0050] In the winding direction of the core structure extension 12, the specific installation positions of the ends of the positive current collector 21 and the negative current collector 31 can be implemented in the following three ways:

[0051] First implementation method: such as Figure 1 As shown, the end of the positive current collector 21 is located outside the end of the negative current collector 31 (that is, the outermost ring of the positive current collector 21 is located at the outermost ring of the cell 1, and at this time, the end of the positive current collector 21 is located outside the end of the negative current collector 31). At this time, during the battery charge and discharge cycle, the positive electrode 2 expands, and there is no negative electrode 3 outside the positive electrode 2, so it will not affect the breakage of the negative electrode 3, nor will it cause battery failure.

[0052] The second implementation method: as follows Figure 3 As shown, the end of the positive current collector 21 is located inside the end of the negative current collector 31 (that is, the outermost ring of the negative current collector 31 is located at the outermost ring of the cell 1, and at this time, the end of the negative current collector 31 is located outside the end of the positive current collector 21). When the end of the positive current collector 21 is located inside the end of the negative current collector 31, the end of the positive current collector 21 extends beyond the end of the negative current collector 31. At this time, during the battery charge and discharge cycle, the positive electrode 2 expands, and the outer side of the end of the positive electrode 2 extends beyond the negative electrode 3, so it will not affect the breakage of the negative electrode 3, nor will it cause battery failure.

[0053] The third implementation method: such as Figure 4 As shown, the end of the positive current collector 21 is located inside the end of the negative current collector 31 (i.e., the outermost ring of the negative current collector 31 is located at the outermost ring of the cell 1, and at this time, the end of the negative current collector 31 is located outside the end of the positive current collector 21). When the end of the positive current collector 21 is located inside the end of the negative current collector 31, the end of the positive current collector 21 is located between the negative tab 33 and the end of the negative current collector 31. At this time, the position between the negative tab 33 and the negative current collector 31 is not coated with the negative active material layer 32. This position is an inactive area. During the battery charge and discharge cycle, even if the positive electrode sheet 2 expands and cuts off the position between the negative tab 33 and the negative current collector 31, cutting off this inactive area will not cause current flow, nor will it affect the normal power supply of the negative tab 33, and will ultimately not affect battery failure.

[0054] The positive electrode tab 23 is fixed to the positive electrode current collector 21 by welding, and the negative electrode tab 33 is fixed to the negative electrode current collector 31 by welding.

[0055] In the winding direction of the core structure extension 12, the clockwise angles formed between the line connecting the center point of the core structure extension 12 and the positive electrode 23, and between the center point of the core structure extension 12 and the negative electrode 33, are set at a certain angle. Specifically, in the winding direction of the core structure extension 12, the clockwise angles formed between the line connecting the center point of the core structure extension 12 and the positive electrode 23, and between the center point of the core structure extension 12 and the negative electrode 33, range from 80 to 180 degrees, thereby meeting the required installation position requirements.

[0056] Both the positive current collector 21 and the negative current collector 31 include one or more of natural graphite and artificial graphite.

[0057] An embodiment of this utility model also provides a secondary battery, which includes the above-described cell structure, a cell shell (not shown in the drawings), and an electrolyte (not shown in the drawings). The cell structure is installed inside the cell shell, and the electrolyte fills the space between the cell structure and the cell shell.

[0058] The battery cell casing is made of aluminum.

[0059] The advantages of the cell structure and secondary battery of this utility model are that, when the positive electrode tab 23 and the negative electrode tab 33 are set at a certain angle, the specific installation position layout of the ends of the three positive current collectors 21 and the negative current collectors 31 can avoid the situation where the negative electrode 3 breaks when the positive electrode 2 expands, ultimately leading to battery failure.

[0060] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A battery cell structure, characterized in that, It includes battery cells (1); The battery cell (1) includes a wound core structure (11) and a wound core structure extension (12) disposed on the outer ring of the wound core structure (11); The core structure (11) includes a positive electrode (2), a negative electrode (3) and a separator (4), wherein the separator (4) separates the positive electrode (2) and the negative electrode (3); The positive electrode sheet (2) is composed of a positive electrode active material layer (22) and a positive electrode current collector (21); The negative electrode sheet (3) is composed of a negative electrode active material layer (32) and a negative electrode current collector (31); The core structure extension (12) is formed by the positive current collector (21), the negative current collector (31) and the separator (4) of the core structure (11) extending outward and being wound together. The positive current collector (21) of the core structure extension (12) is provided with a positive electrode tab (23); The negative electrode current collector (31) of the core structure extension (12) is provided with a negative electrode tab (33); In the winding direction of the core structure extension (12), the positive electrode tab (23) and the negative electrode tab (33) are offset at a certain angle; In the winding direction of the core structure extension (12), the end of the positive current collector (21) is located outside the end of the negative current collector (31), or the end of the positive current collector (21) is located inside the end of the negative current collector (31); When the end of the positive current collector (21) is located inside the end of the negative current collector (31), the end of the positive current collector (21) extends beyond the end of the negative current collector (31), or the end of the positive current collector (21) is located between the negative electrode tab (33) and the end of the negative current collector (31).

2. The cell structure according to claim 1, characterized in that, The positive electrode tab (23) is fixed to the positive electrode current collector (21) by welding, and the negative electrode tab (33) is fixed to the negative electrode current collector (31) by welding.

3. The cell structure according to claim 1, characterized in that, In the winding direction of the core structure extension (12), the clockwise angle formed between the line connecting the center point of the core structure extension (12) and the positive electrode tab (23) and the line connecting the center point of the core structure extension (12) and the negative electrode tab (33) is set at a certain angle.

4. A cell structure according to claim 3, characterized in that, In the winding direction of the core structure extension (12), the clockwise angle formed between the line connecting the center point of the core structure extension (12) and the positive electrode tab (23) and the line connecting the center point of the core structure extension (12) and the negative electrode tab (33) is 80-180 degrees.

5. A cell structure according to claim 1, characterized in that, Both the positive current collector (21) and the negative current collector (31) include one or more of natural graphite and artificial graphite.

6. A cell structure according to claim 1, characterized in that, The positive electrode tab (23) is provided with a positive electrode protective adhesive paper (24) on the outside.

7. A cell structure according to claim 1, characterized in that, The negative electrode tab (33) is provided with a negative electrode protective adhesive paper (34) on the outside.

8. A secondary battery, characterized in that, It includes a cell structure, a cell housing, and an electrolyte as described in any one of claims 1-7, wherein the cell structure is disposed inside the cell housing, and the electrolyte is filled between the cell structure and the cell housing.

9. A secondary battery according to claim 8, characterized in that, The battery cell casing is made of aluminum.

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