Lithium battery structure with multiple tabs

Abstract

A lithium battery structure with multiple tabs. The lithium battery structure is characterized by: comprising a positive electrode sheet, a negative electrode sheet and an isolation layer located between the positive electrode sheet and the negative electrode sheet; the positive electrode sheet, the isolation layer and the negative electrode sheet being wound in the lengthwise direction thereof to form a cylindrical winding body; the positive electrode sheet and the negative electrode sheet, and a plurality of non-equidistant and unequal-length tab pieces which are integrated with the positive electrode sheet or the negative electrode sheet being arranged on one side edge of the positive electrode sheet or the negative electrode sheet; the tab pieces on the positive electrode sheet being mutually oppositely superposed after being wound to form a cylindrical winding body, so as to form a tab of the positive electrode sheet; and the tab pieces on the negative electrode sheet being mutually oppositely superposed after being wound to form a cylindrical winding body, so as to form a tab of the negative electrode sheet. In a battery designed using the structure, the electrical conductivity of the positive electrode sheet and the electrical conductivity of the negative electrode sheet are both significantly improved, the internal resistance of the battery is reduced, and the phenomenon of overheating of the battery is reduced.

Description

Lithium battery structure with multiple tabs Technical Field

[0001] The present invention relates to a lithium battery and a cylindrical battery structure, in particular to a lithium battery structure with multiple tabs. Background Art

[0002] The positive electrodes of existing lithium batteries and cylindrical batteries are generally single or multiple aluminum strips (as positive electrode tabs) ultrasonically welded to aluminum foil (as positive electrode sheets), and the aluminum strips then serve as positive electrode conductive posts. The negative electrodes are generally single or multiple nickel strips (copper-nickel composite strips, as negative electrode tabs) ultrasonically welded to copper foil (as negative electrode sheets), and the nickel strips (copper-nickel composite strips) then serve as negative electrode conductive posts. Commonly used consumer batteries use single tabs. Although the tabs have high processing efficiency, the internal resistance of the battery is large, and the battery is prone to heat generation when used at high power, which greatly reduces the battery performance. Although the use of multiple tabs (i.e., multiple tabs need to be welded to the positive or negative electrode sheets) can reduce internal resistance and reduce heat generation, it results in low production efficiency.

[0003] A Chinese patent "A method for preparing a multi-electrode lithium battery" was retrieved, with publication number CN114024042A. The method for preparing a multi-electrode lithium battery includes: step 1, intermittently coating the active material slurry on the current collector to form a plurality of positive and negative electrode sheets with alternating coated areas and empty foil areas; step 2, rolling the electrode sheets to a preset thickness; step 3, cutting the rolled electrode sheets into preset widths; step 4, placing the positive and negative electrode sheets perpendicular to each other, and winding them in sequence along the direction of the positive or negative electrode sheets to form a core, so that preset empty foil areas are retained at both ends as tabs; step 5, removing the separators in the empty foil areas around the core, and then welding the empty foils into tabs; step 6, packaging, baking, injecting, forming and dividing the capacity to prepare a multi-electrode lithium-ion battery. Although the patent has two positive and negative electrode tabs, this structure cannot be used in wound batteries. Technical issues

[0004] In view of this, an object of the present invention is to provide a lithium battery structure with multiple tabs, which has a reasonable design and is conducive to reducing the internal resistance of the battery and reducing the heating of the battery. Technical Solutions

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] The present invention has a multi-electrode lithium battery structure, characterized by comprising a positive electrode sheet, a negative electrode sheet, and a separator located between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet, the separator, and the negative electrode sheet are wound into a cylindrical winding body along their length direction;

[0007] The positive electrode sheet and the negative electrode sheet, as well as one side of the positive electrode sheet or the negative electrode sheet, are provided with a plurality of pole tabs of unequal distance and length integral therewith. After the pole tabs on the positive electrode sheet are wound into a cylindrical winding body, they are stacked opposite each other to form the pole tabs of the positive electrode sheet; after the pole tabs on the negative electrode sheet are wound into a cylindrical winding body, they are stacked opposite each other to form the pole tabs of the negative electrode sheet.

[0008] Preferably, the tabs of the above-mentioned positive electrode sheet are welded into one piece by resistance welding or ultrasonic welding, and the tabs of the negative electrode sheet are welded into one piece by resistance welding or ultrasonic welding. The tabs of the integrated positive electrode sheet are connected to the battery cap through resistance welding, ultrasonic welding or laser welding via the current collector, and the tabs of the integrated negative electrode sheet are connected to the battery casing through resistance welding or ultrasonic welding via the current collector.

[0009] Preferably, the tab of the positive electrode sheet is bent so as to be close to the end face of the cylindrical winding body, and the tab of the positive electrode sheet close to the end face of the cylindrical winding body is welded to one end of the current collecting sheet. The tab of the negative electrode sheet is bent so as to be close to the end face of the cylindrical winding body, and the tab of the negative electrode sheet close to the end face of the cylindrical winding body is welded to one end of the current collecting sheet. The left and right sides of the tab of the positive electrode sheet or the tab of the negative electrode sheet are flush.

[0010] Preferably, an insulating gasket is provided between the end surface of the cylindrical winding body and the current collecting sheet.

[0011] Preferably, the positive electrode sheet and the tab sheet are formed by cutting or laser cutting the same sheet material, so that the positive electrode sheet and the tab sheet are integrated.

[0012] Preferably, the negative electrode sheet and the tab sheet are formed by cutting or laser cutting the same sheet material, so that the negative electrode sheet and the tab sheet are integrated.

[0013] Preferably, the positive electrode sheet is an aluminum foil sheet with a thickness of 5-25 μm; the negative electrode sheet is a copper foil sheet with a thickness of 3-20 μm.

[0014] Preferably, the mutually stacked tabs are directly welded and fixed to the positive terminal or the negative terminal of the lithium battery.

[0015] Preferably, the length of the positive electrode sheet is 300-5000 mm, and the length of the negative electrode sheet is 330-5060 mm.

[0016] Preferably, the length of the positive electrode sheet is 700 mm, the width of all the tabs is 5 mm, the shortest tab is 10 mm, the spacing between adjacent tabs increases by 2 mm, and the height of adjacent tabs increases by 0.2 mm.

[0017] Preferably, the length of the negative electrode sheet is 740 mm, the width of all the tabs is 5 mm, the shortest tab is 6 mm, the spacing between adjacent tabs increases by 2 mm, and the height of adjacent tabs increases by 0.3 mm.

[0018] Preferably, a protective layer is provided at the position where the positive electrode sheet is connected to its tab sheet, and at the position where the negative electrode sheet is connected to its tab sheet. The width of the protective layer is 1-15 mm, and the protective layer is one of a boehmite layer, a ceramic particle layer, an alumina layer or a silica layer. Beneficial effects

[0019] The winding core (i.e., cylindrical wound body) or battery using the structural design of the present invention significantly increases the conductivity of both the positive and negative electrode sheets, reduces the battery's internal resistance, and minimizes heat generation. The structure, with the positive or negative electrode tabs on top and the current collector sheet at the bottom (closer to the end face of the winding core), makes welding intuitive, facilitates online testing, and improves product qualification rates by 10-30% compared to existing technologies. (The poor qualification rate of existing technologies is often caused by welding the positive or negative electrode tabs to the current collector sheet.) BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a schematic diagram of the cross-sectional structure of the positive electrode sheet and the negative electrode sheet assembled;

[0021] FIG2 is a schematic diagram of the structure of the positive electrode sheet in an unfolded state;

[0022] FIG3 is a schematic diagram of the structure of the negative electrode sheet in an unfolded state;

[0023] FIG4 is a schematic diagram of the front view of a cylindrical winding body formed by winding a positive electrode sheet and a negative electrode sheet;

[0024] FIG5 is a schematic diagram of the cross-sectional structure of a cylindrical wound body formed by winding a positive electrode sheet and a negative electrode sheet.

[0025] FIG6 is a schematic diagram of another embodiment of FIG2;

[0026] FIG7 is a schematic diagram of another embodiment of FIG2;

[0027] FIG8 is a schematic diagram of the cross-sectional structure of the battery of the present invention. Modes for Carrying Out the Invention

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by ordinary technicians in the technical field to which the present application belongs.

[0030] The lithium battery structure with multiple tabs of the present invention includes a positive electrode sheet 1, a negative electrode sheet 2 and an isolation layer 3 located between the positive electrode sheet and the negative electrode sheet (that is, the positive electrode sheet 1, the negative electrode sheet 2 and the insulating separator 3 are stacked on each other). The positive electrode sheet 1 and the negative electrode sheet 2 are both rectangular in shape. The positive electrode sheet, the isolation layer 3 and the negative electrode sheet 2 are wound into a cylindrical winding body 01 (that is, the winding core) along their length direction; the above structure is an existing technology, and the contents about the isolation layer 3 and the like are not repeated here.

[0031] One side of the positive electrode sheet is provided with a plurality of pole tabs (positive electrode tab 101) of unequal spacing and unequal lengths, and one side of the negative electrode sheet is provided with a plurality of pole tabs (negative electrode tab 201) of unequal spacing and unequal lengths, the positive electrode tab 101 and the negative electrode tab 201 are rectangular in shape. Preferably, the sides of the positive electrode sheet and the negative electrode sheet on which the pole tabs are provided are the opposite sides of the rectangular electrode sheet, but of course they can also be located on the same side of the rectangle.

[0032] After being wound into a cylindrical winding body, the various tabs on the positive electrode sheet 1 are stacked opposite each other to form the tabs 102 (or positive electrode busbars) of the positive electrode sheet; after being wound into a cylindrical winding body, the various tabs on the negative electrode sheet are stacked opposite each other to form the tabs 202 (or negative electrode busbars) of the negative electrode sheet. The tabs of the positive electrode sheet (or positive electrode busbars) are welded together by resistance welding or ultrasonic welding, and the tabs of the negative electrode sheet (or negative electrode busbars) are welded together by resistance welding or ultrasonic welding. The tabs of the integrated positive electrode sheet are connected to the battery cap 6 through the current collector 5 by resistance welding, ultrasonic welding or laser welding, and the tabs of the integrated negative electrode sheet are connected to the battery casing 7 through the current collector 5 by resistance welding or ultrasonic welding.

[0033] The coil core and cylindrical battery adopt a structural design in which a plurality of pole tabs of unequal distances and lengths are provided on one side of the positive electrode sheet, and a plurality of pole tabs of unequal distances and lengths are provided on one side of the negative electrode sheet. This significantly increases the conductivity of the positive and negative electrode sheets, reduces the internal resistance of the battery, and reduces the heat generation of the battery.

[0034] After being bent, the tab 102 of the positive electrode sheet is close to the end face of the winding core, and the side of the tab of the positive electrode sheet close to the end face of the winding core is welded to one end of the current collecting sheet. In the above structure, even if one end of the current collecting sheet is pressed underneath by the tab 102 of the positive electrode sheet (meaning that the current collecting sheet is pressed closer to the end face of the winding core), the tab 202 of the negative electrode sheet is bent and close to the end face of the winding core, and the side of the tab of the negative electrode sheet close to the end face of the winding core is welded to one end of the current collecting sheet (meaning that the current collecting sheet is pressed closer to the end face of the winding core). The left and right sides of the tab of the positive electrode sheet or the tab of the negative electrode sheet are flush, that is, the widths of each tab of the positive electrode sheet or each tab of the negative electrode sheet are the same.

[0035] The structure, with the positive or negative electrode tabs on top and the current collector at the bottom (closer to the end face of the winding core), makes welding intuitive, facilitates online testing, and improves product qualification rates by 10-30% compared to existing technologies. (The poor qualification rate of existing technologies is often caused by the welding of the positive or negative electrode tabs to the current collector.)

[0036] In order to improve the insulation effect, an insulating gasket 8 is provided between the end face of the winding core and the current collecting sheet. The insulating gasket can be a hard plastic sheet with a thickness of 2-3 mm. At the same time, a recessed groove for accommodating the current collecting sheet 5 and the tab can be provided on the insulating gasket 8.

[0037] During production, the positive electrode sheet and its tab sheet are cut or laser cut from the same sheet material (such as a rectangular aluminum foil sheet) so that the positive electrode sheet and the tab sheet are integrated; similarly, the negative electrode sheet and its tab sheet are cut or laser cut from the same sheet material (such as a rectangular copper foil sheet) so that the negative electrode sheet and the tab sheet are integrated.

[0038] Preferably, the positive electrode sheet is a rectangular aluminum foil sheet with a thickness of 5-25 μm; the negative electrode sheet is a rectangular copper foil sheet with a thickness of 3-20 μm.

[0039] Preferably, the length of the positive electrode sheet is 300-5000 mm, and the length of the negative electrode sheet is 330-5060 mm; in one embodiment, the length of the positive electrode sheet is 700 mm, the width of all the tabs is 5 mm, the shortest height is 10 mm, the spacing between adjacent tabs increases by 2 mm, and the height of adjacent tabs increases by 0.2 mm; the length of the negative electrode sheet is 740 mm, the width of all the tabs is 5 mm, the shortest height is 6 mm, the spacing between adjacent tabs increases by 2 mm, and the height of adjacent tabs increases by 0.3 mm.

[0040] In order to play a protective role, a protective layer 4 is provided at the position where the positive electrode sheet is connected to its electrode tab sheet, and at the position where the negative electrode sheet is connected to its electrode tab sheet. The width of the protective layer is 1-15 mm, and the protective layer is one of a boehmite layer, a ceramic particle layer, an aluminum oxide layer or a silicon dioxide layer.

[0041] The winding core (i.e., cylindrical wound body) or battery using the structural design of the present invention significantly increases the conductivity of both the positive and negative electrode sheets, reduces the battery's internal resistance, and minimizes heat generation. The structure, with the positive or negative electrode tabs on top and the current collector sheet at the bottom (closer to the end face of the winding core), makes welding intuitive, facilitates online testing, and improves product qualification rates by 10-30% compared to existing technologies. (The poor qualification rate of existing technologies is often caused by welding the positive or negative electrode tabs to the current collector sheet.)

[0042] The preferred embodiments listed above further illustrate the objectives, technical solutions and advantages of the present invention in detail. It should be understood that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A lithium battery structure with multiple tabs, characterized in that: It includes a positive electrode sheet, a negative electrode sheet and a separation layer located between the positive electrode sheet and the negative electrode sheet, wherein the positive electrode sheet, the separation layer and the negative electrode sheet are wound into a cylindrical winding body along the length direction thereof; The positive electrode sheet and the negative electrode sheet, and one side of the positive electrode sheet or the negative electrode sheet are provided with a plurality of pole ear sheets of unequal distance and length which are integrated therewith. After the pole ear sheets on the positive electrode sheet are wound into a cylindrical winding body, they are stacked opposite to each other to form the pole ear of the positive electrode sheet; after the pole ear sheets on the negative electrode sheet are wound into a cylindrical winding body, they are stacked opposite to each other to form the pole ear of the negative electrode sheet.

2. The lithium battery structure with multiple tabs according to claim 1, characterized in that: The tabs of the positive electrode sheet are welded together by resistance welding or ultrasonic welding, and the tabs of the negative electrode sheet are welded together by resistance welding or ultrasonic welding. The tabs of the integrated positive electrode sheet are connected to the battery cap through resistance welding, ultrasonic welding or laser welding via a current collector, and the tabs of the integrated negative electrode sheet are connected to the battery shell through resistance welding or ultrasonic welding via a current collector.

3. The lithium battery structure with multiple tabs according to claim 1, characterized in that: The tab of the positive electrode sheet is bent so as to be close to the end face of the cylindrical winding body, and the side of the tab of the positive electrode sheet close to the end face of the cylindrical winding body is welded to one end of the current collector. The tab of the negative electrode sheet is bent so as to be close to the end face of the cylindrical winding body, and the side of the tab of the negative electrode sheet close to the end face of the cylindrical winding body is welded to one end of the current collector. The left and right sides of the tab of the positive electrode sheet or the tab of the negative electrode sheet are flush.

4. The cylindrical battery multi-electrode winding core structure according to claim 2 or 3, characterized in that: An insulating gasket is provided between the end surface of the columnar winding body and the current collecting sheet.

5. The lithium battery structure with multiple tabs according to claim 1, characterized in that: The positive electrode sheet and its tab sheet are formed by cutting or laser cutting the same sheet material, so that the positive electrode sheet and the tab sheet are integrated; the negative electrode sheet and its tab sheet are formed by cutting or laser cutting the same sheet material, so that the negative electrode sheet and the tab sheet are integrated.

6. The lithium battery structure with multiple tabs according to claim 1, 2, 3 or 5, characterized in that: The positive electrode sheet is an aluminum foil sheet with a thickness of 5-25um; the negative electrode sheet is a copper foil sheet with a thickness of 3-20um.

7. The lithium battery structure with multiple tabs according to claim 6, characterized in that: The length of the positive electrode sheet is 300-5000 mm, and the length of the negative electrode sheet is 330-5060 mm.

8. The lithium battery structure with multiple tabs according to claim 7, characterized in that: The length of the positive electrode sheet is 700 mm, the width of all the tab sheets is 5 mm, the shortest height is 10 mm, the spacing between adjacent tab sheets increases by 2 mm, and the height of adjacent tab sheets increases by 0.2 mm.

9. The lithium battery structure with multiple tabs according to claim 8, characterized in that: The negative electrode sheet has a length of 740 mm, and all of its tab sheets have a width of 5 mm, the shortest tab sheet has a height of 6 mm, the spacing between adjacent tab sheets increases by 2 mm, and the height of adjacent tab sheets increases by 0.3 mm.

10. The lithium battery structure with multiple tabs according to claim 9, characterized in that: A protective layer is provided at the position where the positive electrode sheet is connected to its pole tab sheet, and at the position where the negative electrode sheet is connected to its pole tab sheet. The width of the protective layer is 1-15 mm, and the protective layer is one of a boehmite layer, a ceramic particle layer, an aluminum oxide layer or a silicon dioxide layer.

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