Lithium battery and manufacturing method therefor

Abstract

The present application provides a lithium battery and a manufacturing method therefor. The lithium battery comprises a housing (60) and a battery cell group mounted in the housing (60); two ends of the housing (60) are respectively provided with end openings; the battery cell group comprises a positive tab (102) and a negative tab (103); the positive tab (102) extends out of the housing (60) from the end opening of a first end of the housing (60); the negative tab (103) extends out of the housing (60) from the end opening of a second end of the housing (60); and the battery cell group is formed by connecting in parallel at least two different types of roll cores. According to the lithium battery, the battery cell manufacturing efficiency and pass rate can be improved, and the process compatibility and the material utilization rate are improved.

Description

Lithium-ion battery and method for manufacturing the same

[0001] This application claims priority to the Chinese invention patent with application number "202410370295.5", application date "March 28, 2024", and invention name "Lithium-ion battery and its manufacturing method". Technical Field

[0002] The present application relates to the field of battery manufacturing technology, and in particular to a lithium-ion battery and a method for manufacturing the same. Background Art

[0003] Blade batteries, also known as lithium-ion batteries, offer excellent performance and are widely used in new energy vehicles, consumer electronics, power tools, and other fields. The production process for blade batteries primarily involves the preparation, lamination, cutting, and assembly of positive and negative electrode sheets. The positive and negative electrode sheets are cut from coils and stacked to create a laminated cell. The single cell is then inserted into a housing to complete assembly.

[0004] Currently, the production process of blade batteries has the following problems:

[0005] 1. The manufacturing efficiency of laminated cells is low, and due to the relative sliding between the positive and negative plates, it is prone to risks such as internal short circuits, making it unsuitable for large-scale industrial production;

[0006] Second, when the length of the blade battery changes frequently, the manufacturing dimensions of processes such as front-end coating and lamination need to be adjusted. The difficulty of adjustment leads to poor process compatibility.

[0007] 3. When a single stacked battery cell is detected as defective, it needs to be scrapped as a whole, resulting in low material utilization.

[0008] Application Contents

[0009] The main purpose of this application is to provide a lithium-ion battery and a manufacturing method thereof, which can improve the manufacturing efficiency and qualification rate of battery cells, and improve process compatibility and material utilization.

[0010] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a lithium-ion battery is provided, comprising a shell and a battery cell group installed in the shell, wherein end openings are respectively provided at both ends of the shell, and the battery cell group comprises a positive electrode ear and a negative electrode ear, the positive electrode ear extends out of the shell from the end opening at the first end of the shell, and the negative electrode ear extends out of the shell from the end opening at the second end of the shell, and the battery cell group is formed by at least two different types of winding cores connected in parallel.

[0011] In some embodiments, at least two different types of winding cores are coated with insulating tape at connection locations.

[0012] In some embodiments, at least two different types of winding cores are entirely covered with an insulating film.

[0013] In some embodiments, the lithium-ion battery further includes a positive electrode cover plate and a negative electrode cover plate, the positive electrode cover plate includes a positive electrode adapter plate, a positive electrode substrate and a positive electrode column, the negative electrode cover plate includes a negative electrode adapter plate, a negative electrode substrate and a negative electrode column, the positive electrode adapter plate and the positive electrode column are respectively located on both sides of the positive electrode substrate and are insulated and isolated from the positive electrode substrate, the positive electrode adapter plate and the positive electrode column are conductively connected, the negative electrode adapter plate and the negative electrode column are respectively located on both sides of the negative electrode substrate and are insulated and isolated from the negative electrode substrate, the negative electrode adapter plate and the negative electrode column are conductively connected, the positive electrode ear of the battery cell group is fixedly connected to the positive electrode adapter plate, the negative electrode ear of the battery cell group is fixedly connected to the negative electrode adapter plate, the positive electrode substrate is buckled and fixed at the end opening of the first end of the shell, and the negative electrode substrate is buckled and fixed at the end opening of the second end of the shell.

[0014] In some embodiments, the battery cell group includes a first roll core and a second roll core, the upper end of the first roll core is provided with a positive pole ear, and the lower end is provided with a positive pole ear, all of the positive pole ears and negative pole ears are located on the first side of the thickness direction of the first roll core, the upper end of the second roll core is provided with a positive pole ear and a negative pole ear, and the lower end is provided with a negative pole ear, the positive pole ear and the negative pole ear at the upper end of the second roll core are located on the second side of the thickness direction of the second roll core, the negative pole ear at the lower end of the second roll core is located on the first side of the thickness direction of the second roll core, the positive pole ear at the lower end of the first roll core is connected to the positive pole ear at the upper end of the second roll core, and the negative pole ear at the lower end of the first roll core is connected to the negative pole ear at the upper end of the second roll core.

[0015] In some embodiments, the first winding core and the second winding core are staggered, the positive electrode ear at the lower end of the first winding core is opposite to the positive electrode ear at the upper end of the second winding core, and are connected by a connecting piece, and the negative electrode ear at the lower end of the first winding core is opposite to the negative electrode ear at the upper end of the second winding core, and are connected by a connecting piece; or, the first winding core and the second winding core are flush along the thickness direction, the positive electrode ear at the lower end of the first winding core is bent upward, and the positive electrode ear at the upper end of the second winding core is bent downward and docked with the positive electrode ear at the lower end of the first winding core. , connecting pieces are respectively provided on both sides of the positive ear of the first winding core and the second winding core, the positive ear at the lower end of the first winding core is connected to the positive ear at the upper end of the second winding core through the connecting piece, the negative ear at the lower end of the first winding core is bent upward, and the negative ear at the upper end of the second winding core is bent downward and docked with the negative ear at the lower end of the first winding core, and connecting pieces are respectively provided on both sides of the negative ear of the first winding core and the second winding core, the negative ear at the lower end of the first winding core is connected to the negative ear at the upper end of the second winding core through the connecting piece.

[0016] In some embodiments, the battery cell group includes a first winding core, the upper end of the first winding core is provided with a positive pole ear, and the lower end is provided with a positive pole ear and a negative pole ear, all of the positive pole ears and negative pole ears are located on the first side of the thickness direction of the first winding core, the first winding core also includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet of the first winding core includes an end pole ear area and a pole-free pole ear area, the end pole ear area and the pole-free pole ear area are alternately arranged along the length direction of the positive electrode sheet of the first winding core, and the upper and lower ends of the end pole ear area are distributed with positive pole ears, the negative electrode sheet of the first winding core includes a lower pole ear area and a pole-free pole ear area, the lower pole ear area and the pole-free pole ear area of ​​the negative electrode sheet of the first winding core are alternately arranged along the length direction of the negative electrode sheet of the first winding core, and the lower end of the lower pole ear area of ​​the negative electrode sheet of the first winding core is distributed with a negative pole ear.

[0017] In some embodiments, the battery cell group includes a second winding core, the upper end of the second winding core is provided with a positive pole ear and a negative pole ear, and the lower end is provided with a negative pole ear, the positive pole ear and the negative pole ear at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, the second winding core also includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet of the second winding core includes an upper pole ear area and a pole-free pole ear area, the upper pole ear area and the pole-free pole ear area of ​​the positive electrode sheet of the second winding core are alternately arranged along the length direction of the positive electrode sheet of the second winding core, the upper end of the upper pole ear area of ​​the positive electrode sheet of the second winding core is distributed with a positive pole ear, the negative electrode sheet of the second winding core includes an upper pole ear area and a lower pole ear area, the upper pole ear area and the lower pole ear area of ​​the negative electrode sheet of the second winding core are alternately arranged along the length direction of the negative electrode sheet of the second winding core, the upper end of the upper pole ear area of ​​the negative electrode sheet of the second winding core is distributed with a negative pole ear, and the lower end of the lower pole ear area of ​​the negative electrode sheet of the second winding core is distributed with a negative pole ear.

[0018] In some embodiments, the battery cell group includes a first winding core, a third winding core, and a fourth winding core, the upper end of the first winding core is provided with a positive electrode ear, the lower end is provided with a positive electrode ear and a negative electrode ear, all of the positive electrode ears and the negative electrode ears are located on the first side of the thickness direction of the first winding core, the upper end of the third winding core is provided with a positive electrode ear and a negative electrode ear, the lower end is provided with a negative electrode ear, all of the positive electrode ears and the negative electrode ears of the third winding core are located on the first side of the thickness direction of the third winding core, the upper end of the fourth winding core is provided with a positive electrode ear and negative electrode ears, and the lower end is provided with a positive electrode ear and a negative electrode ear, all the positive electrode ears and negative electrode ears of the fourth core are located on the second side of the thickness direction of the fourth core, the positive electrode ear at the lower end of the first core is connected to the positive electrode ear at the upper end of the fourth core, the negative electrode ear at the lower end of the first core is connected to the negative electrode ear at the upper end of the fourth core, the positive electrode ear at the lower end of the fourth core is connected to the positive electrode ear at the upper end of the third core, and the negative electrode ear at the lower end of the fourth core is connected to the negative electrode ear at the upper end of the third core.

[0019] In some embodiments, the battery cell group includes a first winding core, a second winding core and a fourth winding core, the upper end of the first winding core is provided with a positive electrode ear, and the lower end is provided with a positive electrode ear and a negative electrode ear, and all the positive electrode ears and negative electrode ears are located on the first side of the thickness direction of the first winding core, the upper end of the second winding core is provided with a positive electrode ear and a negative electrode ear, and the lower end is provided with a negative electrode ear, the positive electrode ear and the negative electrode ear at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode ear at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core, the upper end of the fourth winding core is provided with a positive electrode ear and a negative electrode ear, and the lower end is provided with a positive electrode ear and a negative electrode ear, and all the positive electrode ears and negative electrode ears of the fourth winding core are located On the second side of the fourth winding core in the thickness direction, a first winding core, two fourth winding cores and a second winding core are connected in sequence, the positive electrode ear at the lower end of the first winding core is connected to the positive electrode ear at the upper end of the fourth winding core, the negative electrode ear at the lower end of the first winding core is connected to the negative electrode ear at the upper end of the first fourth winding core, the positive electrode ear at the lower end of the first fourth winding core is connected to the positive electrode ear at the upper end of the second fourth winding core, the negative electrode ear at the lower end of the first fourth winding core is connected to the negative electrode ear at the upper end of the second fourth winding core, the positive electrode ear at the lower end of the second fourth winding core is connected to the positive electrode ear at the upper end of the second winding core, and the negative electrode ear at the lower end of the second fourth winding core is connected to the negative electrode ear at the upper end of the second winding core.

[0020] In some embodiments, the battery cell group includes a first winding core, a second winding core, a third winding core and a fourth winding core, the upper end of the first winding core is provided with a positive electrode ear, and the lower end is provided with a positive electrode ear and a negative electrode ear, all of the positive electrode ears and the negative electrode ears are located on the first side of the thickness direction of the first winding core, the upper end of the second winding core is provided with a positive electrode ear and a negative electrode ear, and the lower end is provided with a negative electrode ear, the positive electrode ear and the negative electrode ear at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, the negative electrode ear at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core, the upper end of the third winding core is provided with a positive electrode ear and a negative electrode ear, and the lower end is provided with a negative electrode ear, and the third winding core All the positive and negative ears are located on the first side of the thickness direction of the third core, the upper end of the fourth core is provided with a positive ear and a negative ear, and the lower end is provided with a positive ear and a negative ear, and all the positive and negative ears of the fourth core are located on the second side of the thickness direction of the fourth core. When the total number of cores of the lithium-ion battery X is an even number and X≥2, the combination type of the battery cell group is one first core + (X-2) fourth cores + one second core; when the total number of cores of the lithium-ion battery X is an odd number and X≥2, the combination type of the battery cell group is one first core + (X-2) fourth cores + one third core.

[0021] According to another aspect of the present application, a method for manufacturing the above-mentioned lithium-ion battery is provided, comprising:

[0022] preparing a battery cell group, wherein the battery cell group is formed by connecting at least two different types of winding cores in parallel;

[0023] Install the battery cell group into the shell from the end opening of the shell;

[0024] The positive electrode tab of the battery cell group extends out of the shell from the end opening of the first end of the shell, and the negative electrode tab extends out of the shell from the end opening of the second end of the shell.

[0025] In some embodiments, the manufacturing method further comprises:

[0026] A positive electrode cover is disposed at the end opening of the first end of the shell;

[0027] The positive tab of the battery cell group is fixedly connected to the positive electrode adapter of the positive electrode cover plate, and the positive electrode substrate is buckled and fixed to the end opening of the first end of the shell;

[0028] A negative electrode cover is disposed at the end opening of the second end of the shell;

[0029] The negative electrode tab of the battery cell group is fixedly connected to the negative electrode adapter of the negative electrode cover, and the negative electrode substrate is buckled and fixed to the end opening of the second end of the shell.

[0030] In some embodiments, the steps of preparing a battery cell assembly include:

[0031] Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab, and the lower end of the first winding core is provided with a positive electrode tab and a negative electrode tab, and all the positive electrode tabs and the negative electrode tabs are located on a first side in the thickness direction of the first winding core;

[0032] Prepare a second winding core, wherein the positive electrode tab and the negative electrode tab at the upper end of the second winding core are located on the second side in the thickness direction of the second winding core, and the negative electrode tab at the lower end of the second winding core is located on the first side in the thickness direction of the second winding core;

[0033] The positive tab at the bottom of the first winding core is connected to the positive tab at the top of the second winding core, and the negative tab at the bottom of the first winding core is connected to the negative tab at the top of the second winding core to form a battery cell group.

[0034] In some embodiments, the step of preparing the first core comprises:

[0035] Prepare a positive electrode sheet, wherein the positive electrode sheet includes alternating end tab regions and a tab-free region, wherein positive tabs are distributed at both upper and lower ends of the end tab regions, and the end tab regions and the tab-free region are separated by a fold line;

[0036] Prepare a negative electrode sheet, wherein the negative electrode sheet includes a lower end tab region and a tab-free region that are alternately arranged, a negative electrode tab is distributed at the lower end of the lower end tab region of the negative electrode sheet, and the lower end tab region and the tab-free region are separated by a fold line;

[0037] Coating positive electrode material on the tab areas at both ends and the tab-free area of ​​the positive electrode sheet;

[0038] Coating negative electrode material on the lower tab area and the tab-free area of ​​the negative electrode sheet;

[0039] Stack the separator-negative electrode sheet-separator-positive electrode sheet together in the order from bottom to top to form a four-layer unit;

[0040] The four-layer unit is wound to form a first core.

[0041] In some embodiments, the step of preparing the second core comprises:

[0042] Prepare a positive electrode sheet, wherein the positive electrode sheet includes an upper tab region and a tab-free region that are alternately arranged, a positive tab is distributed on the upper end of the upper tab region, and the upper tab region and the tab-free region are separated by a fold line;

[0043] Prepare a negative electrode sheet, wherein the negative electrode sheet includes an upper tab region and a lower tab region that are alternately arranged, wherein a negative tab is distributed at the upper end of the upper tab region of the negative electrode sheet, and a negative tab is distributed at the lower end of the lower tab region of the negative electrode sheet, and the lower tab region and the tab-free region are separated by a fold line;

[0044] Coating the positive electrode material on the upper tab area and the tab-free area of ​​the positive electrode sheet;

[0045] Coating negative electrode material on the upper tab area and the lower tab area of ​​the negative electrode sheet;

[0046] Stack the separator-negative electrode sheet-separator-positive electrode sheet together in the order from bottom to top to form a four-layer unit;

[0047] The four-layer unit is wound to form a second core.

[0048] In some embodiments, the steps of preparing a battery cell assembly include:

[0049] Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab, and the lower end of the first winding core is provided with a positive electrode tab and a negative electrode tab, and all the positive electrode tabs and the negative electrode tabs are located on a first side in the thickness direction of the first winding core;

[0050] Prepare a third core, wherein the upper end of the third core is provided with a positive electrode tab and a negative electrode tab, and the lower end of the third core is provided with a negative electrode tab, and all the positive electrode tabs and negative electrode tabs of the third core are located on a first side in the thickness direction of the third core;

[0051] Prepare a fourth winding core, wherein the upper end of the fourth winding core is provided with a positive electrode tab and a negative electrode tab, and the lower end of the fourth winding core is provided with a positive electrode tab and a negative electrode tab, and all the positive electrode tabs and negative electrode tabs of the fourth winding core are located on the second side of the thickness direction of the fourth winding core;

[0052] The positive electrode ear at the lower end of the first winding core is connected to the positive electrode ear at the upper end of the fourth winding core, the negative electrode ear at the lower end of the first winding core is connected to the negative electrode ear at the upper end of the fourth winding core, the positive electrode ear at the lower end of the fourth winding core is connected to the positive electrode ear at the upper end of the third winding core, and the negative electrode ear at the lower end of the fourth winding core is connected to the negative electrode ear at the upper end of the third winding core.

[0053] In some embodiments, the step of preparing the third winding core comprises:

[0054] Prepare a positive electrode sheet, wherein the positive electrode sheet includes an upper tab region and a tab-free region that are alternately arranged, a positive tab is distributed on the upper end of the upper tab region, and the upper tab region and the tab-free region are separated by a fold line;

[0055] Prepare a negative electrode sheet, wherein the negative electrode sheet includes alternating end tab regions and a tab-free region, wherein negative tabs are distributed at the upper and lower ends of the end tab regions of the negative electrode sheet, and the end tab regions and the tab-free region are separated by a fold line;

[0056] Coating the positive electrode material on the upper tab area and the tab-free area of ​​the positive electrode sheet;

[0057] Coating negative electrode material on the tab areas at both ends and the tab-free area of ​​the negative electrode sheet;

[0058] Stack the separator-negative electrode sheet-separator-positive electrode sheet together in the order from bottom to top to form a four-layer unit;

[0059] The four-layer unit is wound to form a third core.

[0060] In some embodiments, the step of preparing the fourth core comprises:

[0061] Prepare a positive electrode sheet, wherein the positive electrode sheet includes alternating end tab regions and a tab-free region, wherein positive tabs are distributed at the upper and lower ends of the end tab regions of the positive electrode sheet, and the end tab regions and the tab-free region are separated by a fold line;

[0062] Prepare a negative electrode sheet, wherein the negative electrode sheet includes alternating end tab regions and a tab-free region, wherein negative tabs are distributed at the upper and lower ends of the end tab regions of the negative electrode sheet, and the end tab regions and the tab-free region are separated by a fold line;

[0063] Coating positive electrode material on the tab areas at both ends and the tab-free area of ​​the positive electrode sheet;

[0064] Coating negative electrode material on the tab areas at both ends and the tab-free area of ​​the negative electrode sheet;

[0065] Stack the separator-negative electrode sheet-separator-positive electrode sheet together in the order from bottom to top to form a four-layer unit;

[0066] The four-layer unit is wound to form a fourth core.

[0067] In some embodiments, the steps of preparing a battery cell assembly include:

[0068] Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab, and the lower end of the first winding core is provided with a positive electrode tab and a negative electrode tab, and all the positive electrode tabs and the negative electrode tabs are located on a first side in the thickness direction of the first winding core;

[0069] Prepare a second winding core, wherein the positive electrode tab and the negative electrode tab at the upper end of the second winding core are located on the second side in the thickness direction of the second winding core, and the negative electrode tab at the lower end of the second winding core is located on the first side in the thickness direction of the second winding core;

[0070] Prepare a fourth winding core, wherein the upper end of the fourth winding core is provided with a positive electrode tab and a negative electrode tab, and the lower end of the fourth winding core is provided with a positive electrode tab and a negative electrode tab, and all the positive electrode tabs and negative electrode tabs of the fourth winding core are located on the second side of the thickness direction of the fourth winding core;

[0071] A first winding core, two fourth winding cores and a second winding core are connected in sequence, the positive electrode ear at the lower end of the first winding core is connected to the positive electrode ear at the upper end of the fourth winding core, the negative electrode ear at the lower end of the first winding core is connected to the negative electrode ear at the upper end of the first fourth winding core, the positive electrode ear at the lower end of the first fourth winding core is connected to the positive electrode ear at the upper end of the second fourth winding core, the negative electrode ear at the lower end of the first fourth winding core is connected to the negative electrode ear at the upper end of the second fourth winding core, the positive electrode ear at the lower end of the second fourth winding core is connected to the positive electrode ear at the upper end of the second winding core, and the negative electrode ear at the lower end of the second fourth winding core is connected to the negative electrode ear at the upper end of the second winding core.

[0072] According to the technical solution of the present application, a lithium-ion battery includes a shell and a cell group installed in the shell. The two ends of the shell are respectively provided with end openings. The cell group includes a positive electrode ear and a negative electrode ear. The positive electrode ear extends out of the shell from the end opening of the first end of the shell, and the negative electrode ear extends out of the shell from the end opening of the second end of the shell. The cell group is formed by connecting at least two different types of cores in parallel. The lithium-ion battery is manufactured by connecting multiple different types of cores in parallel. On the one hand, it can effectively improve the efficiency of cell manufacturing, and on the other hand, it can greatly improve the qualified rate of cell manufacturing. Since the lithium-ion battery is formed by combining multiple types of cores, the size requirements of different lithium-ion batteries can be adapted by increasing or decreasing the number of parallel cores. The process compatibility is significantly improved. When a core is defective, the defective core can be eliminated without scrapping the entire core, which greatly improves the material utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0074] FIG1 is a schematic diagram of the structure of the first winding core in Example 1 of the present application;

[0075] FIG2 is a schematic diagram of the expansion of the pole piece corresponding to the first winding core in Example 1 of the present application;

[0076] FIG3 is a schematic diagram of the structure of the second winding core in Example 1 of the present application;

[0077] FIG4 is a schematic diagram of the expansion of the pole piece corresponding to the second winding core in Example 1 of the present application;

[0078] FIG5 is a schematic diagram of the three-dimensional structure after the first winding core and the second winding core are connected in Example 1 of the present application;

[0079] FIG6 is a schematic diagram of the structure after the first winding core and the second winding core are connected in Example 1 of the present application;

[0080] FIG7 is a schematic diagram of the first winding core and the second winding core being connected and then glued in Example 1 of the present application;

[0081] FIG8 is a schematic diagram of the three-dimensional structure of the first winding core and the second winding core after the tab is stretched in Example 1 of the present application;

[0082] FIG9 is a schematic structural diagram of the first winding core and the second winding core after the tab is stretched in Example 1 of the present application;

[0083] FIG10 is a schematic diagram of the first winding core and the second winding core after being coated with an insulating film in Example 1 of the present application;

[0084] FIG11 is a schematic structural diagram of the first winding core, the second winding core, and the cover plate after assembly in Example 1 of the present application;

[0085] FIG12 is a bottom view of the structure of the first winding core, the second winding core and the cover plate after being assembled in Example 1 of the present application;

[0086] Figure 13 is a schematic diagram of the relative positions of the positive electrode cover plate, the negative electrode cover plate and the winding core;

[0087] FIG14 is a schematic diagram of the positive electrode cover plate, the negative electrode cover plate and the housing after assembly;

[0088] FIG15 is a partial cross-sectional view taken along the SS direction of FIG11;

[0089] FIG16 is a schematic diagram of the expansion of the third winding core and its pole piece in the second embodiment of the present application;

[0090] FIG17 is a schematic diagram of the expansion of the third winding core, the fourth winding core and the pole pieces thereof in the second embodiment of the present application;

[0091] FIG18 is a schematic diagram of the three-dimensional structure of the second embodiment of the present application after the three winding cores are connected;

[0092] FIG19 is a schematic diagram of the structure of the three winding cores after connection in Example 2 of the present application;

[0093] FIG20 is a schematic diagram of the three-dimensional structure of the three-core winding after the tab is stretched in Example 2 of the present application;

[0094] FIG21 is a schematic diagram of the structure of the three winding cores after the tabs are stretched in Example 2 of the present application;

[0095] FIG22 is a schematic diagram of the three-dimensional structure of the four winding cores after connection in Example 3 of the present application;

[0096] FIG23 is a schematic diagram of the structure of the four winding cores after connection in Example 3 of the present application;

[0097] FIG24 is a flow chart of a method for manufacturing a lithium-ion battery according to an embodiment of the present application.

[0098] Among them, the above-mentioned drawings include the following figure marks: 10. Winding core: 101. Winding core body; 102. Positive electrode ear; 103. Negative electrode ear; 20. Pole sheet: 201. Positive electrode sheet; 202. Negative electrode sheet; 203. Winding line; 30. Connecting sheet; 40. Insulating tape; 50. Insulating film; 60. Shell; 70. Positive electrode cover: 701. Positive electrode adapter sheet; 702. Positive electrode substrate; 703. Positive electrode column; 80. Negative electrode cover: 801. Negative electrode adapter sheet; 802. Negative electrode substrate; 803. Negative electrode column; M, two end ear areas; N, upper end ear area; P, lower end ear area; Q, no ear area. DETAILED DESCRIPTION

[0099] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0100] With reference to Figures 1 to 22, the present application provides a lithium-ion battery, comprising a shell 60 and a cell group installed in the shell 60, wherein end openings are respectively provided at both ends of the shell 60, and the cell group comprises a positive electrode ear 102 and a negative electrode ear 103, wherein the positive electrode ear 102 extends out of the shell 60 from the end opening at the first end of the shell 60, and the negative electrode ear 103 extends out of the shell 60 from the end opening at the second end of the shell 60, and the cell group is formed by at least two different types of winding cores connected in parallel.

[0101] The lithium-ion battery is manufactured by connecting multiple different types of cores in parallel. On the one hand, it can effectively improve the efficiency of battery cell manufacturing, and on the other hand, it can greatly improve the qualified rate of battery cell manufacturing. Since the lithium-ion battery is formed by a combination of multiple types of cores, the size requirements of different lithium-ion batteries can be adapted by increasing or decreasing the number of parallel cores. The process compatibility is significantly improved. When a core is defective, the defective core can be removed without scrapping the entire core, which greatly improves the material utilization rate.

[0102] In this embodiment, the battery cells 10 constituting the battery cell group include a battery cell body 101 , on which a positive electrode tab 102 and a negative electrode tab 103 are respectively provided. Different types of battery cells 10 are distinguished according to the different distribution positions of the positive electrode tab 102 and the negative electrode tab 103 on the battery cell body 101 .

[0103] In one embodiment, at least two different types of winding cores are coated at the connection position with an insulating tape 40. The purpose of coating the welding position with the insulating tape 40 is to prevent the spread of welding dust.

[0104] In one embodiment, at least two different types of cores are entirely coated with an insulating film 50. The insulating film 50 covers the surfaces of the at least two cores connected in parallel. This serves to secure the relative positions of the at least two cores forming the cell pack and also protects the core surfaces from scratches during subsequent placement into the battery case.

[0105] In one embodiment, the lithium-ion battery further includes a positive electrode cover plate 70 and a negative electrode cover plate 80, the positive electrode cover plate 70 includes a positive electrode adapter plate 701, a positive electrode substrate 702 and a positive electrode column 703, the negative electrode cover plate 80 includes a negative electrode adapter plate 801, a negative electrode substrate 802 and a negative electrode column 803, the positive electrode adapter plate 701 and the positive electrode column 703 are respectively located on both sides of the positive electrode substrate 702 and are insulated and isolated from the positive electrode substrate 702, the positive electrode adapter plate 701 and the positive electrode column 703 are conductively connected, and the negative electrode adapter plate 801 and the negative electrode column 803 are respectively located on both sides of the negative electrode substrate 802 and are insulated and isolated from the negative electrode substrate 802. The negative electrode adapter 801 and the negative electrode column 803 are conductively connected. The positive electrode ear 102 of the battery cell group is fixedly connected to the positive electrode adapter 701, and the negative electrode ear 103 of the battery cell group is fixedly connected to the negative electrode adapter 801. The positive electrode substrate 702 is buckled and fixed at the end opening of the first end of the shell 60, and the negative electrode substrate 802 is buckled and fixed at the end opening of the second end of the shell 60.

[0106] In this embodiment, the positive electrode adapter 701 on the positive electrode cover 70 is connected to the positive electrode post 703, and the positive electrode adapter 701 and the positive electrode post 703 are each insulated from the positive electrode substrate 702 by an insulating member. The negative electrode adapter 801 on the negative electrode cover 80 is connected to the negative electrode post 803, and the negative electrode adapter 801 and the negative electrode post 803 are each insulated from the negative electrode substrate 802 by an insulating member. After the positive electrode substrate 702 and the negative electrode substrate 802 are flipped over and snapped onto the shell opening, the positive electrode substrate 702 and the negative electrode substrate 802 are respectively welded to the end opening of the shell 60 by laser welding, thereby assembling and fixing the positive and negative electrode cover 70 and 80 to the shell 60.

[0107] With reference to Figures 1 to 9, in one embodiment, the battery cell group includes a first winding core A and a second winding core B. The upper end of the first winding core A is provided with a positive electrode tab 102, and the lower end is provided with a positive electrode tab 102 and a negative electrode tab 103. All the positive electrode tabs 102 and negative electrode tabs 103 are located on the first side of the thickness direction of the first winding core A. The upper end of the second winding core B is provided with a positive electrode tab 102 and a negative electrode tab 103, and the lower end is provided with a negative electrode tab 103. The positive electrode tab 102 and the negative electrode tab 103 at the upper end of the second winding core B are located on the second side of the thickness direction of the second winding core B, and the negative electrode tab 103 at the lower end of the second winding core B is located on the first side of the thickness direction of the second winding core B. The positive electrode tab 102 at the lower end of the first winding core A is connected to the positive electrode tab 102 at the upper end of the second winding core B, and the negative electrode tab 103 at the lower end of the first winding core A is connected to the negative electrode tab 103 at the upper end of the second winding core B.

[0108] In one embodiment, the first winding core A and the second winding core B are staggered, the positive electrode ear 102 at the lower end of the first winding core A is opposite to the positive electrode ear 102 at the upper end of the second winding core B, and are connected by a connecting piece 30, and the negative electrode ear 103 at the lower end of the first winding core A is opposite to the negative electrode ear 103 at the upper end of the second winding core B, and are connected by a connecting piece 30; or, the first winding core A and the second winding core B are flush along the thickness direction, the positive electrode ear 102 at the lower end of the first winding core A is bent upward, and the positive electrode ear 102 at the upper end of the second winding core B is bent downward and docked with the positive electrode ear 102 at the lower end of the first winding core A, and the first winding core A connecting piece 30 is provided on both sides of the positive electrode ear 102 of the first core A and the second core B, and the positive electrode ear 102 at the lower end of the first core A is connected to the positive electrode ear 102 at the upper end of the second core B through the connecting piece 30. The negative electrode ear 103 at the lower end of the first core A is bent upward, and the negative electrode ear 103 at the upper end of the second core B is bent downward and connected to the negative electrode ear 103 at the lower end of the first core A. A connecting piece 30 is provided on both sides of the negative electrode ear 103 of the first core A and the second core B, and the negative electrode ear 103 at the lower end of the first core A is connected to the negative electrode ear 103 at the upper end of the second core B through the connecting piece 30.

[0109] In one embodiment, the battery cell group includes a first core A, the upper end of the first core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, all of the positive electrode ears 102 and the negative electrode ears 103 are located on the first side of the thickness direction of the first core A, the first core A also includes a positive electrode sheet 201 and a negative electrode sheet 202, the positive electrode sheet 201 of the first core A includes two end electrode ear areas and a non-electrode ear area, the two end electrode ear areas and the non-electrode ear area are alternately arranged along the length direction of the positive electrode sheet 201 of the first core A, and the upper and lower ends of the two end electrode ear areas are distributed with positive electrode ears 102, the negative electrode sheet 202 of the first core A includes a lower end electrode ear area and a non-electrode ear area, the lower end electrode ear area and the non-electrode ear area of ​​the negative electrode sheet 202 of the first core A are alternately arranged along the length direction of the negative electrode sheet 202 of the first core A, and the lower end of the lower end electrode ear area of ​​the negative electrode sheet 202 of the first core A is distributed with a negative electrode ear 103.

[0110] In one embodiment, the battery cell group includes a second core B, the upper end of the second core B is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a negative electrode ear 103, the positive electrode ear 102 and the negative electrode ear 103 at the upper end of the second core B are located on the second side of the thickness direction of the second core B, the second core B also includes a positive electrode sheet 201 and a negative electrode sheet 202, the positive electrode sheet 201 of the second core B includes an upper end ear area and a non-electrode ear area, the upper end ear area and the non-electrode ear area of ​​the positive electrode sheet 201 of the second core B are along the positive electrode sheet 201 of the second core B. 1, the upper end of the upper end tab area of ​​the positive electrode sheet 201 of the second winding core B is distributed with the positive electrode tab 102, the negative electrode sheet 202 of the second winding core B includes an upper end tab area and a lower end tab area, the upper end tab area and the lower end tab area of ​​the negative electrode sheet 202 of the second winding core B are alternately arranged along the length direction of the negative electrode sheet 202 of the second winding core B, the upper end of the upper end tab area of ​​the negative electrode sheet 202 of the second winding core B is distributed with the negative electrode tab 103, and the lower end of the lower end tab area of ​​the negative electrode sheet 202 of the second winding core B is distributed with the negative electrode tab 103.

[0111] Figure 1 is a structural schematic diagram of the first winding core A in Example 1 of the present application. When observed from the top view, the upper and lower ends of the first winding core A have pole ears extending therefrom, wherein the upper end is the positive pole ear 102, and the lower end has the positive pole ear 102 and the negative pole ear 103; when observed from the side view, the pole ears at the left and right ends are both located on the same side of the thickness direction of the first winding core A.

[0112] Figure 2 is a schematic diagram of the expansion of the electrode sheet corresponding to the first winding core A in Example 1 of the present application. The first winding core A includes an electrode sheet 20, and the electrode sheet 20 includes a positive electrode sheet 201 and a negative electrode sheet 202. The positive electrode sheet 201 is arranged alternately with a terminal tab region M and a non-terminal tab region Q. The terminal tab region M and the non-terminal tab region Q are both coated with positive electrode material. At the same time, positive electrode tabs 102 are distributed at the upper and lower ends of the terminal tab region M. The negative electrode sheet 202 is arranged alternately with a lower terminal tab region P and a non-terminal tab region Q. The lower terminal tab region P and the non-terminal tab region Q are both coated with negative electrode material. At the same time, a negative electrode tab 103 is distributed only at the lower end of the lower terminal tab region P. Arrange them in order from bottom to top, stack the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 together to form a four-layer unit, and the winding fold lines 203 on the positive electrode sheet 201 and the negative electrode sheet 202 coincide, and then the above four-layer unit is unidirectionally wound to obtain the first winding core A.

[0113] Figure 3 is a schematic structural diagram of the second winding core B in Example 1 of the present application. When viewed from the top, the second winding core B has pole ears extending from the upper and lower ends, wherein the upper end is the positive pole ear 102 and the negative pole ear 103, and the lower end has the negative pole ear 103; when viewed from the side, the pole ears at the left and right ends are respectively located on the upper and lower sides of the second winding core B in the thickness direction.

[0114] Figure 4 is a schematic diagram of the unfolding of the electrode sheet corresponding to the second winding core B in Example 1 of the present application. The second winding core B includes an electrode sheet 20, and the electrode sheet 20 includes a positive electrode sheet 201 and a negative electrode sheet 202. The positive electrode sheet 201 is arranged alternately with an upper end tab region N and a tab-free region Q. The upper end tab region N and the tab-free region Q are both coated with positive electrode material. At the same time, the positive electrode tab 102 is distributed only at the upper end of the upper end tab region N. The negative electrode sheet 202 is arranged alternately with an upper end tab region N and a lower end tab region P. The upper end tab region N and the lower end tab region P are both coated with negative electrode material. At the same time, the negative electrode tab 103 is distributed at the upper end of the upper end tab region N and the lower end of the lower end tab region P. Arrange them in order from bottom to top, first stack the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 together to form a four-layer unit, and the winding lines 203 on the positive electrode sheet 201 and the negative electrode sheet 202 coincide, and then the above four-layer unit is unidirectionally wound to obtain the second winding core B.

[0115] Figures 5 and 6 are schematic diagrams of the first winding core A and the second winding core B after the connection is completed in Example 1 of the present application. As shown in the figures, the positive pole ears 102 of the two are opposite to each other, and the negative pole ears 103 are opposite to each other. At the same time, connecting pieces 30 are placed on the upper and lower sides of the relative pole ears, respectively. Finally, an ultrasonic welder is used to weld the pole ears and the connecting pieces 30 together, thereby achieving connectivity between the positive pole ears 102 and the positive pole ears 102, and the negative pole ears 103 and the negative pole ears 103.

[0116] FIG7 is a schematic diagram of the first winding core A and the second winding core B being connected and then glued in Example 1 of the present application. Based on FIG5 , the welding position is covered with insulating tape 40 to prevent the diffusion of welding dust.

[0117] Figures 8 and 9 are schematic diagrams of the first winding core A and the second winding core B after the tabs are stretched in Example 1 of the present application. Based on Figure 7, the first winding core A and the second winding core B are stretched to the same height plane. At this time, the stretched tabs are clamped between the first winding core A and the second winding core B.

[0118] With reference to Figures 16 to 21, in one embodiment, the battery cell group includes a first winding core A, a third winding core C, and a fourth winding core D. The upper end of the first winding core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103. All the positive electrode ears 102 and the negative electrode ears 103 are located on the first side of the thickness direction of the first winding core A. The upper end of the third winding core C is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a negative electrode ear 103. All the positive electrode ears 102 and the negative electrode ears 103 of the third winding core C are located on the first side of the thickness direction of the third winding core C. The upper end of the fourth winding core D is provided with a positive electrode. The positive electrode ear 102 and the negative electrode ear 103 are arranged at the lower end, and all the positive electrode ears 102 and the negative electrode ears 103 of the fourth core D are located on the second side of the thickness direction of the fourth core D. The positive electrode ear 102 at the lower end of the first core A is connected to the positive electrode ear 102 at the upper end of the fourth core D, and the negative electrode ear 103 at the lower end of the first core A is connected to the negative electrode ear 103 at the upper end of the fourth core D. The positive electrode ear 102 at the lower end of the fourth core D is connected to the positive electrode ear 102 at the upper end of the third core C, and the negative electrode ear 103 at the lower end of the fourth core D is connected to the negative electrode ear 103 at the upper end of the third core C.

[0119] Figure 16 is a schematic diagram of the unfolding of the third winding core C and its electrode sheet in Example 2 of the present application. When viewed from the top, the third winding core C has electrode ears extending from the upper and lower ends, wherein the upper end is the positive electrode ear 102 and the negative electrode ear 103, and the lower end has the negative electrode ear 103; when viewed from the side, the electrode ears at the left and right ends are both located on the same side of the thickness direction of the third winding core C.

[0120] The third winding core C includes a pole piece 20, which includes a positive pole piece 201 and a negative pole piece 202. The positive pole piece 201 is arranged alternately with an upper end tab region N and a tab-free region Q. The upper end tab region N and the tab-free region Q are both coated with positive electrode material. At the same time, a positive pole piece 102 is distributed at the upper end of the upper end tab region N. The negative pole piece 202 is arranged alternately with an end tab region M and a tab-free region Q. The end tab region M and the tab-free region Q are both coated with negative electrode material. At the same time, negative pole pieces 103 are respectively distributed at the upper and lower ends of the end tab region M. Arranged in order from bottom to top, the separator-negative pole piece 202-separator-positive pole piece 201 are first stacked together to form a four-layer unit, and the winding fold lines 203 on the positive pole piece 201 and the negative pole piece 202 coincide. Then, the above four-layer unit is unidirectionally wound to obtain the third winding core C.

[0121] Figure 17 is a schematic diagram of the unfolding of the fourth winding core D and its electrode sheet in Example 2 of the present application. When viewed from the top, the fourth winding core D has electrode ears extending from the upper and lower ends, wherein the upper end has a positive electrode ear 102 and a negative electrode ear 103, and the lower end has a positive electrode ear 102 and a negative electrode ear 103; when viewed from the side, the electrode ears at the left and right ends are both located on the same side in the thickness direction of the third winding core C.

[0122] The fourth winding core D includes a pole piece 20, which includes a positive pole piece 201 and a negative pole piece 202. The positive pole piece 201 is arranged alternately with a pole tab region M at both ends and a pole tab-free region Q. Both the pole tab region M and the pole tab-free region Q are coated with a positive electrode material. At the same time, positive pole tabs 102 are respectively distributed at the upper and lower ends of the pole tab region M at both ends. The negative pole piece 202 is arranged alternately with a pole tab region M at both ends and a pole tab-free region Q. Both the pole tab region M and the pole tab-free region Q are coated with a negative electrode material. At the same time, negative pole tabs 103 are respectively distributed at the upper and lower ends of the pole tab region M at both ends. Arranged in order from bottom to top, the separator-negative pole piece 202-separator-positive pole piece 201 are first stacked together to form a four-layer unit, and the winding fold lines 203 on the positive pole piece 201 and the negative pole piece 202 coincide. Then, the above four-layer unit is unidirectionally wound to obtain the fourth winding core D.

[0123] Figures 18 and 19 are schematic diagrams of the three cores after connection in Example 2 of the present application. The above-mentioned first core A, fourth core D, and third core C are arranged as shown in the figure, and the positive pole ears 102 are opposite to the positive pole ears 102, and the negative pole ears 103 are opposite to the negative pole ears 103. At the same time, connecting pieces 30 are placed on the upper and lower sides of the relative pole ears, respectively. Finally, an ultrasonic welder is used to weld the pole ears and the connecting pieces 30 together, thereby realizing the connection between the positive pole ears 102 and the positive pole ears 102, and the negative pole ears 103 and the negative pole ears 103. Finally, the insulating tape 40 is coated on the weld surface.

[0124] Figures 20 and 21 are schematic diagrams of the tab stretching process performed on the three winding cores in Example 2 of the present application. The first winding core A, the fourth winding core D, and the third winding core C are stretched to the same height plane. The stretched tabs are then clamped between the first winding core A and the fourth winding core D, and between the fourth winding core D and the third winding core C, respectively. Finally, assembly is performed according to the process of Figures 10 to 15.

[0125] In this embodiment, since the pole tabs of the first core A and the third core C are both located on the first side of the core, and the pole tabs of the fourth core D are both located on the second side of the core, the first core A and the third core C can be directly combined with the fourth core D to form a three-core structure.

[0126] 22 and 23 , in one embodiment, the battery cell group includes a first winding core A, a second winding core B, and a fourth winding core D. The upper end of the first winding core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103. All the positive electrode ears 102 and the negative electrode ears 103 are located on the first side of the thickness direction of the first winding core A. The upper end of the second winding core B is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a negative electrode ear 103. The positive electrode ear 102 and the negative electrode ear 103 at the upper end of the second winding core B are located on the second side of the thickness direction of the second winding core B, and the negative electrode ear 103 at the lower end of the second winding core B is located on the first side of the thickness direction of the second winding core B. The upper end of the fourth winding core D is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103. All the positive electrode ears of the fourth winding core D 102 and the negative electrode ear 103 are both located on the second side of the thickness direction of the fourth core D. A first core A, two fourth cores D and a second core B are connected in sequence. The positive electrode ear 102 at the lower end of the first core A is connected to the positive electrode ear 102 at the upper end of the fourth core D, the negative electrode ear 103 at the lower end of the first core A is connected to the negative electrode ear 103 at the upper end of the first fourth core D, the positive electrode ear 102 at the lower end of the first fourth core D is connected to the positive electrode ear 102 at the upper end of the second fourth core D, the negative electrode ear 103 at the lower end of the first fourth core D is connected to the negative electrode ear 103 at the upper end of the second fourth core D, the positive electrode ear 102 at the lower end of the second fourth core D is connected to the positive electrode ear 102 at the upper end of the second core B, and the negative electrode ear 103 at the lower end of the second fourth core D is connected to the negative electrode ear 103 at the upper end of the second core B.

[0127] Figures 22 and 23 are schematic diagrams of the four winding cores in Example 3 of the present application after they are connected. The first winding core A, fourth winding core D, fourth winding core D, and second winding core B are arranged as shown, with the positive electrode tabs 102 facing each other and the negative electrode tabs 103 facing each other. Connecting tabs 30 are placed on the upper and lower sides of the opposing tabs, respectively. Finally, the tabs and connecting tabs 30 are welded together using an ultrasonic welder, thereby connecting the positive electrode tabs 102 with the positive electrode tabs 102 and the negative electrode tabs 103 with the negative electrode tabs 103. Finally, insulating tape 40 is applied to the welded surfaces. The first winding core A, fourth winding core D, fourth winding core D, and second winding core B are stretched to the same height plane. At this time, the stretched tabs are clamped between the first winding core A and the fourth winding core D, the fourth winding core D and the fourth winding core D, and the fourth winding core D and the second winding core B, respectively. Finally, assembly is carried out according to the process of Figures 10-15.

[0128] In this embodiment, since the tabs of the first core A are all located on the first side of the core, the upper tabs of the positive tab 102 and the negative tab 103 of the second core B are both located on the second side of the core, and the lower tab of a negative tab is located on the first side of the core, and the tabs at both ends of the fourth core D are face-symmetrical and both are located on the same side of the core, if only one fourth core D is set between the first core A and the second core B, after the positive tab 102 and the negative tab 103 at the lower end of the first core A are connected to the positive tab 102 and the negative tab 103 at one end of the fourth core D, the positive tab 102 and the negative tab 103 at the other end of the fourth core D are located on the same side as the positive tab and the negative tab of the second core B, and the two cannot be connected. Therefore, it is necessary to set two fourth cores D between the first core A and the second core B, wherein the first fourth core D realizes the connection with the first core A, and the second fourth core D switches sides so that the upper and lower pole ears on the second fourth core D and the upper and lower pole ears on the first fourth core D are located on different sides of the core, thereby realizing the connection with the pole ears of the first fourth core D while realizing the connection with the pole ears of the second core B.

[0129] In one embodiment, the battery cell group includes a first winding core A, a second winding core B, a third winding core C and a fourth winding core D, the upper end of the first winding core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, all of the positive electrode ears 102 and the negative electrode ears 103 are located on the first side of the thickness direction of the first winding core A, the upper end of the second winding core B is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a negative electrode ear 103, the positive electrode ear 102 and the negative electrode ear 103 at the upper end of the second winding core B are located on the second side of the thickness direction of the second winding core B, the negative electrode ear 103 at the lower end of the second winding core B is located on the first side of the thickness direction of the second winding core B, the upper end of the third winding core C is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided There is a negative electrode ear 103, all the positive electrode ears 102 and the negative electrode ears 103 of the third core C are located on the first side of the thickness direction of the third core C, the upper end of the fourth core D is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, all the positive electrode ears 102 and the negative electrode ears 103 of the fourth core D are located on the second side of the thickness direction of the fourth core D. When the total number X of the cores of the lithium-ion battery is an even number and X≥2, the combination type of the battery cell group is one first core A + X-2 fourth cores D + one second core B; when the total number X of the cores of the lithium-ion battery is an odd number and X≥2, the combination type of the battery cell group is one first core A + X-2 fourth cores D + one third core C.

[0130] The embodiments of the present application are also applicable to battery cell groups with more groups of fourth cores D. Based on the above analysis, depending on the number of fourth cores D contained in the battery cell group, when the total number of cores X of the lithium-ion battery is an even number and X≥2, the combination type of the battery cell group can be a first core A + X-2 fourth cores D + a second core B; when the total number of cores X of the lithium-ion battery is an odd number and X≥2, the combination type of the battery cell group can be a first core A + X-2 fourth cores D + a third core C. The cores are combined in this manner, thereby meeting the design requirements of various different types of battery cell groups, further improving the applicability of the battery cell group, improving the design flexibility of the lithium-ion battery, reducing design costs, improving the battery cell manufacturing efficiency and pass rate, and improving process compatibility and material utilization.

[0131] Referring to Figure 24 , according to an embodiment of the present application, the manufacturing method of the above-mentioned lithium-ion battery includes: preparing a battery cell group, which is formed by connecting at least two different types of winding cores in parallel; loading the battery cell group into the shell 60 from the end opening of the shell 60; and making the positive electrode ear 102 of the battery cell group extend out of the shell 60 from the end opening of the first end of the shell 60, and the negative electrode ear 103 extend out of the shell 60 from the end opening of the second end of the shell 60.

[0132] In one embodiment, the manufacturing method further includes: configuring a positive electrode cover plate 70 at the end opening of the first end of the shell 60; fixing the positive electrode tab 102 of the battery cell group to the positive electrode adapter plate 701 of the positive electrode cover plate 70, and snapping and fixing the positive electrode substrate 702 at the end opening of the first end of the shell 60; configuring a negative electrode cover plate 80 at the end opening of the second end of the shell 60; fixing the negative electrode tab 103 of the battery cell group to the negative electrode adapter plate 801 of the negative electrode cover plate 80, and snapping and fixing the negative electrode substrate 802 at the end opening of the second end of the shell 60.

[0133] In one embodiment, the steps of preparing a battery cell group include: preparing a first roll core A, wherein the upper end of the first roll core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, and all the positive electrode ears 102 and negative electrode ears 103 are located on the first side of the thickness direction of the first roll core A; preparing a second roll core B, wherein the positive electrode ear 102 and the negative electrode ear 103 at the upper end of the second roll core B are located on the second side of the thickness direction of the second roll core B, and the negative electrode ear 103 at the lower end of the second roll core B is located on the first side of the thickness direction of the second roll core B; connecting the positive electrode ear 102 at the lower end of the first roll core A with the positive electrode ear 102 at the upper end of the second roll core B, and connecting the negative electrode ear 103 at the lower end of the first roll core A with the negative electrode ear 103 at the upper end of the second roll core B to form a battery cell group.

[0134] In one embodiment, the steps of preparing the first winding core A include: preparing a positive electrode sheet 201, wherein the positive electrode sheet 201 includes alternating end tab regions and tab-free regions, positive tabs 102 are distributed at the upper and lower ends of the end tab regions, and the end tab regions and tab-free regions are separated by a folding line 203; preparing a negative electrode sheet 202, wherein the negative electrode sheet 202 includes alternating lower tab regions and tab-free regions, negative tabs 103 are distributed at the lower end of the lower tab region of the negative electrode sheet 202, and the lower tab region and tab-free regions are separated by a folding line 203; coating positive electrode materials on the end tab regions and tab-free regions of the positive electrode sheet 201; coating negative electrode materials on the lower tab region and tab-free regions of the negative electrode sheet 202; stacking the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 together in order from bottom to top to form a four-layer unit; and winding the four-layer unit to form the first winding core A.

[0135] In one embodiment, the steps of preparing the second winding core B include: preparing a positive electrode sheet 201, wherein the positive electrode sheet 201 includes an upper end tab region and a tab-free region arranged alternately, the upper end of the upper end tab region is distributed with a positive electrode tab 102, and the upper end tab region and the tab-free region are separated by a winding fold line 203; preparing a negative electrode sheet 202, wherein the negative electrode sheet 202 includes an upper end tab region and a lower end tab region arranged alternately, and the upper end of the upper end tab region of the negative electrode sheet 202 is distributed with a negative electrode tab 102. 3. A negative electrode tab 103 is distributed at the lower end of the lower tab area of ​​the negative electrode sheet 202, and the lower tab area and the tab-free area are separated by a folding line 203; positive electrode material is coated on the upper tab area and the tab-free area of ​​the positive electrode sheet 201; negative electrode material is coated on the upper tab area and the lower tab area of ​​the negative electrode sheet 202; the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 are stacked together in order from bottom to top to form a four-layer unit; the four-layer unit is wound to form a second winding core B.

[0136] In one embodiment, the steps of preparing a battery cell group include: preparing a first core A, wherein the upper end of the first core A is provided with a positive electrode tab 102, and the lower end is provided with a positive electrode tab 102 and a negative electrode tab 103, and all the positive electrode tabs 102 and the negative electrode tabs 103 are located on the first side of the thickness direction of the first core A; preparing a third core C, wherein the upper end of the third core C is provided with a positive electrode tab 102 and a negative electrode tab 103, and the lower end is provided with a negative electrode tab 103, and all the positive electrode tabs 102 and the negative electrode tabs 103 of the third core C are located on the first side of the thickness direction of the third core C; preparing a fourth core D, wherein the upper end of the fourth core D is provided with a positive electrode tab 1 02 and negative electrode ear 103, the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, and all the positive electrode ears 102 and negative electrode ears 103 of the fourth core D are located on the second side of the thickness direction of the fourth core D; the positive electrode ear 102 at the lower end of the first core A is connected to the positive electrode ear 102 at the upper end of the fourth core D, the negative electrode ear 103 at the lower end of the first core A is connected to the negative electrode ear 103 at the upper end of the fourth core D, the positive electrode ear 102 at the lower end of the fourth core D is connected to the positive electrode ear 102 at the upper end of the third core C, and the negative electrode ear 103 at the lower end of the fourth core D is connected to the negative electrode ear 103 at the upper end of the third core C.

[0137] In one embodiment, the steps of preparing the third winding core C include: preparing a positive electrode sheet 201, wherein the positive electrode sheet 201 includes an upper end tab region and a tab-free region arranged alternately, the upper end of the upper end tab region is distributed with a positive electrode tab 102, and the upper end tab region and the tab-free region are separated by a folding line 203; preparing a negative electrode sheet 202, wherein the negative electrode sheet 202 includes an alternating end tab region and a tab-free region, the upper and lower ends of the end tab regions of the negative electrode sheet 202 are both distributed with negative electrode tabs 103, and the end tab region and the tab-free region are separated by a folding line 203; coating positive electrode materials on the upper end tab region and the tab-free region of the positive electrode sheet 201; coating negative electrode materials on the end tab regions and the tab-free region of the negative electrode sheet 202; stacking the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 together in order from bottom to top to form a four-layer unit; and winding the four-layer unit to form a third winding core C.

[0138] In one embodiment, the steps of preparing the fourth winding core D include: preparing a positive electrode sheet 201, wherein the positive electrode sheet 201 includes two end tab regions and a non-tab region that are alternately arranged, and the upper and lower ends of the two end tab regions of the positive electrode sheet 201 are both distributed with positive tabs 102, and the two end tab regions and the non-tab region are separated by a winding fold line 203; preparing a negative electrode sheet 202, wherein the negative electrode sheet 202 includes two end tab regions and a non-tab region that are alternately arranged, and the negative electrode sheet 202 has a plurality of positive tabs 102 disposed thereon. Negative electrode tabs 103 are distributed at the upper and lower ends of the two end tab areas, and the two end tab areas and the tab-free area are separated by a folding line 203; positive electrode materials are coated on the two end tab areas and the tab-free area of ​​the positive electrode sheet 201; negative electrode materials are coated on the two end tab areas and the tab-free area of ​​the negative electrode sheet 202; the diaphragm-negative electrode sheet 202-diaphragm-positive electrode sheet 201 are stacked together in order from bottom to top to form a four-layer unit; the four-layer unit is wound to form a fourth winding core D.

[0139] In one embodiment, the steps of preparing a battery cell group include: preparing a first core A, wherein the upper end of the first core A is provided with a positive electrode ear 102, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, and all the positive electrode ears 102 and the negative electrode ears 103 are located on the first side of the thickness direction of the first core A; preparing a second core B, wherein the positive electrode ear 102 and the negative electrode ear 103 at the upper end of the second core B are located on the second side of the thickness direction of the second core B, and the negative electrode ear 103 at the lower end of the second core B is located on the first side of the thickness direction of the second core B; preparing a fourth core D, wherein the upper end of the fourth core D is provided with a positive electrode ear 102 and a negative electrode ear 103, and the lower end is provided with a positive electrode ear 102 and a negative electrode ear 103, and all the positive electrode ears 102 and the negative electrode ears 103 of the fourth core D are located on the second side of the thickness direction of the fourth core D. The second side of the degree direction; a first core A, two fourth cores D and a second core B are connected in sequence, the positive electrode ear 102 at the lower end of the first core A is connected to the positive electrode ear 102 at the upper end of the fourth core D, the negative electrode ear 103 at the lower end of the first core A is connected to the negative electrode ear 103 at the upper end of the first fourth core D, the positive electrode ear 102 at the lower end of the first fourth core D is connected to the positive electrode ear 102 at the upper end of the second fourth core D, the negative electrode ear 103 at the lower end of the first fourth core D is connected to the negative electrode ear 103 at the upper end of the second fourth core D, the positive electrode ear 102 at the lower end of the second fourth core D is connected to the positive electrode ear 102 at the upper end of the second core B, and the negative electrode ear 103 at the lower end of the second fourth core D is connected to the negative electrode ear 103 at the upper end of the second core B.

[0140] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0141] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0142] The foregoing description is merely a few embodiments of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A lithium-ion battery, characterized in that: The invention comprises a shell (60) and a battery cell group installed in the shell (60), wherein both ends of the shell (60) are respectively provided with end openings, and the battery cell group comprises a positive electrode ear (102) and a negative electrode ear (103), wherein the positive electrode ear (102) extends out of the shell (60) from the end opening at the first end of the shell (60), and the negative electrode ear (103) extends out of the shell (60) from the end opening at the second end of the shell (60), and the battery cell group is formed by connecting at least two different types of winding cores in parallel.

2. The lithium-ion battery according to claim 1, wherein The at least two different types of winding cores are coated with insulating tape (40) at the connection position.

3. The lithium-ion battery according to claim 1, wherein The exteriors of the at least two different types of winding cores are entirely covered with an insulating film (50).

4. The lithium-ion battery according to claim 1, wherein The lithium-ion battery further comprises a positive electrode cover plate (70) and a negative electrode cover plate (80), wherein the positive electrode cover plate (70) comprises a positive electrode adapter plate (701), a positive electrode substrate (702) and a positive electrode column (703), and the negative electrode cover plate (80) comprises a negative electrode adapter plate (801), a negative electrode substrate (802) and a negative electrode column (803), wherein the positive electrode adapter plate (701) and the positive electrode column (703) are respectively located on both sides of the positive electrode substrate (702) and are insulated and isolated from the positive electrode substrate (702), the positive electrode adapter plate (701) and the positive electrode column (703) are conductively connected, and the negative electrode adapter plate (801) The negative electrode column (803) is respectively located on both sides of the negative electrode substrate (802) and is insulated from the negative electrode substrate (802); the negative electrode adapter (801) and the negative electrode column (803) are conductively connected; the positive electrode ear (102) of the battery cell group is fixedly connected to the positive electrode adapter (701); the negative electrode ear (103) of the battery cell group is fixedly connected to the negative electrode adapter (801); the positive electrode substrate (702) is buckled and fixed to the end opening of the first end of the shell (60); and the negative electrode substrate (802) is buckled and fixed to the end opening of the second end of the shell (60).

5. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group includes a first winding core and a second winding core, wherein the upper end of the first winding core is provided with a positive electrode ear (102), and the lower end is provided with a positive electrode ear (102) and a negative electrode ear (103), all of the positive electrode ears (102) and the negative electrode ears (103) are located on the first side of the thickness direction of the first winding core, the upper end of the second winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear (103), the positive electrode ear (102) and the negative electrode ear (103) at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode ear (103) at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core, the positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the second winding core, and the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the second winding core.

6. The lithium-ion battery according to claim 5, characterized in that The first winding core and the second winding core are staggered, the positive electrode ear (102) at the lower end of the first winding core is opposite to the positive electrode ear (102) at the upper end of the second winding core, and are connected by a connecting piece (30), and the negative electrode ear (103) at the lower end of the first winding core is opposite to the negative electrode ear (103) at the upper end of the second winding core, and are connected by a connecting piece (30); or, the first winding core and the second winding core are flush along the thickness direction, the positive electrode ear (102) at the lower end of the first winding core is bent upward, and the positive electrode ear (102) at the upper end of the second winding core is bent downward and docked with the positive electrode ear (102) at the lower end of the first winding core, and the first winding core and the second winding core are flush along the thickness direction. Connecting pieces (30) are provided on both sides of the positive electrode ear (102), the positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the second winding core through the connecting piece (30), the negative electrode ear (103) at the lower end of the first winding core is bent upward, and the negative electrode ear (103) at the upper end of the second winding core is bent downward and docked with the negative electrode ear (103) at the lower end of the first winding core, and connecting pieces (30) are provided on both sides of the negative electrode ear (103) of the first winding core and the second winding core, and the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the second winding core through the connecting piece (30).

7. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group includes a first winding core, wherein the upper end of the first winding core is provided with a positive electrode ear (102), and the lower end is provided with a positive electrode ear (102) and a negative electrode ear (103), all of the positive electrode ears (102) and the negative electrode ears (103) are located on the first side of the thickness direction of the first winding core, the first winding core also includes a positive electrode sheet (201) and a negative electrode sheet (202), the positive electrode sheet (201) of the first winding core includes two end ear regions and a non-electrode ear region, the two end ear regions and the non-electrode ear region are The areas are alternately arranged along the length direction of the positive electrode sheet (201) of the first winding core, and the upper and lower ends of the two-end tab area are both distributed with positive electrode tabs (102). The negative electrode sheet (202) of the first winding core includes a lower end tab area and a tab-free area. The lower end tab area and the tab-free area of ​​the negative electrode sheet (202) of the first winding core are alternately arranged along the length direction of the negative electrode sheet (202) of the first winding core, and the lower end of the lower end tab area of ​​the negative electrode sheet (202) of the first winding core is distributed with a negative electrode tab (103).

8. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group includes a second winding core, the upper end of the second winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear (103), the positive electrode ear (102) and the negative electrode ear (103) at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, the second winding core also includes a positive electrode sheet (201) and a negative electrode sheet (202), the positive electrode sheet (201) of the second winding core includes an upper end ear region and a non-electrode ear region, the upper end ear region and the non-electrode ear region of the positive electrode sheet (201) of the second winding core are along the positive electrode sheet (201) of the second winding core. The positive electrode sheet (201) of the second winding core is arranged alternately in the longitudinal direction, the upper end of the upper end tab area of ​​the positive electrode sheet (201) is distributed with a positive electrode tab (102), the negative electrode sheet (202) of the second winding core includes an upper end tab area and a lower end tab area, the upper end tab area and the lower end tab area of ​​the negative electrode sheet (202) of the second winding core are alternately arranged along the longitudinal direction of the negative electrode sheet (202) of the second winding core, the upper end of the upper end tab area of ​​the negative electrode sheet (202) of the second winding core is distributed with a negative electrode tab (103), and the lower end of the lower end tab area of ​​the negative electrode sheet (202) of the second winding core is distributed with a negative electrode tab (103).

9. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group comprises a first winding core, a third winding core and a fourth winding core, wherein the upper end of the first winding core is provided with a positive electrode ear (102), and the lower end is provided with a positive electrode ear (102) and a negative electrode ear (103), and all the positive electrode ears (102) and the negative electrode ears (103) are located on the first side of the thickness direction of the first winding core, the upper end of the third winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear (103), and all the positive electrode ears (102) and the negative electrode ears (103) of the third winding core are located on the first side of the thickness direction of the third winding core, and the upper end of the fourth winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), A positive electrode ear (102) and a negative electrode ear (103) are provided at the lower end, and all the positive electrode ears (102) and the negative electrode ears (103) of the fourth winding core are located on the second side of the thickness direction of the fourth winding core, the positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the fourth winding core, the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the fourth winding core, the positive electrode ear (102) at the lower end of the fourth winding core is connected to the positive electrode ear (102) at the upper end of the third winding core, and the negative electrode ear (103) at the lower end of the fourth winding core is connected to the negative electrode ear (103) at the upper end of the third winding core.

10. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group comprises a first winding core, a second winding core and a fourth winding core, wherein the upper end of the first winding core is provided with a positive electrode ear (102), and the lower end is provided with a positive electrode ear (102) and a negative electrode ear (103), and all the positive electrode ears (102) and the negative electrode ears (103) are located on the first side of the thickness direction of the first winding core, the upper end of the second winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear (103), and the second winding core is provided with a positive electrode ear (102) and a negative electrode ear (103). The positive electrode tab (102) and the negative electrode tab (103) at the upper end of the winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode tab (103) at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core. The upper end of the fourth winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and the lower end is provided with a positive electrode tab (102) and a negative electrode tab (103). All the positive electrode tabs (102) and the negative electrode tabs ( 103) are all located on the second side of the thickness direction of the fourth winding core, one first winding core, two fourth winding cores and one second winding core are connected in sequence, the positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the fourth winding core, the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the first fourth winding core, and the positive electrode ear (102) at the lower end of the first fourth winding core is connected to the positive electrode ear (102) at the upper end of the first fourth winding core. ) is connected to the positive electrode ear (102) at the upper end of the second fourth core, the negative electrode ear (103) at the lower end of the first fourth core is connected to the negative electrode ear (103) at the upper end of the second fourth core, the positive electrode ear (102) at the lower end of the second fourth core is connected to the positive electrode ear (102) at the upper end of the second core, and the negative electrode ear (103) at the lower end of the second fourth core is connected to the negative electrode ear (103) at the upper end of the second core.

11. The lithium-ion battery according to any one of claims 1 to 4, characterized in that: The battery cell group comprises a first winding core, a second winding core, a third winding core and a fourth winding core, wherein the upper end of the first winding core is provided with a positive electrode ear (102), and the lower end is provided with a positive electrode ear (102) and a negative electrode ear (103), and all the positive electrode ears (102) and the negative electrode ears (103) are located on the first side of the thickness direction of the first winding core, the upper end of the second winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear (103), the positive electrode ear (102) and the negative electrode ear (103) at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode ear (103) at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core, the upper end of the third winding core is provided with a positive electrode ear (102) and a negative electrode ear (103), and the lower end is provided with a negative electrode ear ( 103), all the positive pole ears (102) and the negative pole ears (103) of the third winding core are located on the first side of the thickness direction of the third winding core, the upper end of the fourth winding core is provided with a positive pole ear (102) and a negative pole ear (103), and the lower end is provided with a positive pole ear (102) and a negative pole ear (103), all the positive pole ears (102) and the negative pole ears (103) of the fourth winding core are located on the second side of the thickness direction of the fourth winding core, when the total number X of winding cores of the lithium-ion battery is an even number and X≥2, the combination type of the battery cell group is one first winding core + (X-2) fourth winding cores + one second winding core; when the total number X of winding cores of the lithium-ion battery is an odd number and X≥2, the combination type of the battery cell group is one first winding core + (X-2) fourth winding cores + one third winding core.

12. A method for manufacturing a lithium-ion battery according to any one of claims 1 to 11, characterized in that: include: preparing a battery cell group, wherein the battery cell group is formed by connecting at least two different types of winding cores in parallel; Installing the battery cell group into the housing (60) through the end opening of the housing (60); The positive electrode tab (102) of the battery cell group extends out of the shell (60) from the end opening of the first end of the shell (60), and the negative electrode tab (103) extends out of the shell (60) from the end opening of the second end of the shell (60).

13. The method for manufacturing a lithium-ion battery according to claim 12, wherein: The manufacturing method further comprises: A positive electrode cover plate (70) is disposed at the end opening of the first end of the shell (60); The positive electrode tab (102) of the battery cell group is fixedly connected to the positive electrode adapter plate (701) of the positive electrode cover plate (70), and the positive electrode substrate (702) is buckled and fixed to the end opening of the first end of the shell (60); A negative electrode cover plate (80) is disposed at the end opening of the second end of the shell (60); The negative electrode tab (103) of the battery cell group is fixedly connected to the negative electrode adapter (801) of the negative electrode cover (80), and the negative electrode substrate (802) is buckled and fixed to the end opening of the second end of the shell (60).

14. The method for manufacturing a lithium-ion battery according to claim 12, wherein: The steps of preparing the battery pack include: Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab (102), and the lower end of the first winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and all the positive electrode tabs (102) and the negative electrode tabs (103) are located on a first side in a thickness direction of the first winding core; Prepare a second winding core, wherein the positive electrode tab (102) and the negative electrode tab (103) at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode tab (103) at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core; The positive electrode tab (102) at the lower end of the first winding core is connected to the positive electrode tab (102) at the upper end of the second winding core, and the negative electrode tab (103) at the lower end of the first winding core is connected to the negative electrode tab (103) at the upper end of the second winding core to form a battery cell group.

15. The method for manufacturing a lithium-ion battery according to claim 14, wherein: The steps of preparing the first core include: A positive electrode sheet (201) is prepared, wherein the positive electrode sheet (201) includes two-end tab regions and a tab-free region that are alternately arranged, positive electrode tabs (102) are distributed at the upper and lower ends of the two-end tab regions, and the two-end tab regions and the tab-free region are separated by a folding line (203); A negative electrode sheet (202) is prepared, wherein the negative electrode sheet (202) includes a lower end tab region and a tab-free region that are alternately arranged, a negative electrode tab (103) is distributed at the lower end of the lower end tab region of the negative electrode sheet (202), and the lower end tab region and the tab-free region are separated by a folding line (203); Coating positive electrode material on the tab regions at both ends and the tab-free region of the positive electrode sheet (201); coating a negative electrode material on the lower end tab region and the tab-free region of the negative electrode sheet (202); The separator-negative electrode sheet (202)-separator-positive electrode sheet (201) are stacked together in order from bottom to top to form a four-layer unit; The four-layer unit is wound to form a first core.

16. The method for manufacturing a lithium-ion battery according to claim 14, wherein: The steps of preparing the second core include: A positive electrode sheet (201) is prepared, wherein the positive electrode sheet (201) includes an upper end tab region and a tab-free region that are alternately arranged, a positive electrode tab (102) is distributed at the upper end of the upper end tab region, and the upper end tab region and the tab-free region are separated by a folding line (203); A negative electrode sheet (202) is prepared, wherein the negative electrode sheet (202) includes an upper end tab region and a lower end tab region that are alternately arranged, a negative electrode tab (103) is distributed at the upper end of the upper end tab region of the negative electrode sheet (202), a negative electrode tab (103) is distributed at the lower end of the lower end tab region of the negative electrode sheet (202), and the lower end tab region and the tab-free region are separated by a folding line (203); Coating a positive electrode material on the upper tab region and the tab-free region of the positive electrode sheet (201); coating negative electrode material on the upper tab region and the lower tab region of the negative electrode sheet (202); The separator-negative electrode sheet (202)-separator-positive electrode sheet (201) are stacked together in order from bottom to top to form a four-layer unit; The four-layer unit is wound to form a second core.

17. The method for manufacturing a lithium-ion battery according to claim 12, wherein: The steps of preparing the battery pack include: Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab (102), and the lower end of the first winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and all the positive electrode tabs (102) and the negative electrode tabs (103) are located on a first side in a thickness direction of the first winding core; Prepare a third winding core, wherein the upper end of the third winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and the lower end is provided with a negative electrode tab (103), and all the positive electrode tabs (102) and negative electrode tabs (103) of the third winding core are located on a first side in a thickness direction of the third winding core; A fourth winding core is prepared, wherein the upper end of the fourth winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and the lower end of the fourth winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and all the positive electrode tabs (102) and negative electrode tabs (103) of the fourth winding core are located on the second side of the thickness direction of the fourth winding core; The positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the fourth winding core, the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the fourth winding core, the positive electrode ear (102) at the lower end of the fourth winding core is connected to the positive electrode ear (102) at the upper end of the third winding core, and the negative electrode ear (103) at the lower end of the fourth winding core is connected to the negative electrode ear (103) at the upper end of the third winding core.

18. The method for manufacturing a lithium-ion battery according to claim 17, wherein: The steps of preparing the third core include: A positive electrode sheet (201) is prepared, wherein the positive electrode sheet (201) includes an upper end tab region and a tab-free region that are alternately arranged, a positive electrode tab (102) is distributed at the upper end of the upper end tab region, and the upper end tab region and the tab-free region are separated by a folding line (203); A negative electrode sheet (202) is prepared, wherein the negative electrode sheet (202) includes alternatingly arranged end tab regions and an end tab-free region, negative electrode tabs (103) are distributed at the upper and lower ends of the end tab regions of the negative electrode sheet (202), and the end tab regions and the end tab-free region are separated by a folding line (203); Coating a positive electrode material on the upper tab region and the tab-free region of the positive electrode sheet (201); coating negative electrode material on the tab regions at both ends and the tab-free region of the negative electrode sheet (202); The separator-negative electrode sheet (202)-separator-positive electrode sheet (201) are stacked together in order from bottom to top to form a four-layer unit; The four-layer unit is wound to form a third core.

19. The method for manufacturing a lithium-ion battery according to claim 17, wherein: The steps of preparing the fourth core include: A positive electrode sheet (201) is prepared, wherein the positive electrode sheet (201) includes alternatingly arranged end tab regions and an end tab-free region, positive electrode tabs (102) are distributed at the upper and lower ends of the end tab regions of the positive electrode sheet (201), and the end tab regions and the end tab-free region are separated by a folding line (203); A negative electrode sheet (202) is prepared, wherein the negative electrode sheet (202) includes alternatingly arranged end tab regions and an end tab-free region, negative electrode tabs (103) are distributed at the upper and lower ends of the end tab regions of the negative electrode sheet (202), and the end tab regions and the end tab-free region are separated by a folding line (203); Coating positive electrode material on the tab regions at both ends and the tab-free region of the positive electrode sheet (201); coating negative electrode material on the tab regions at both ends and the tab-free region of the negative electrode sheet (202); The separator-negative electrode sheet (202)-separator-positive electrode sheet (201) are stacked together in order from bottom to top to form a four-layer unit; The four-layer unit is wound to form a fourth core.

20. The method for manufacturing a lithium-ion battery according to claim 12, wherein: The steps of preparing the battery pack include: Prepare a first winding core, wherein the upper end of the first winding core is provided with a positive electrode tab (102), and the lower end of the first winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and all the positive electrode tabs (102) and the negative electrode tabs (103) are located on a first side in a thickness direction of the first winding core; Prepare a second winding core, wherein the positive electrode tab (102) and the negative electrode tab (103) at the upper end of the second winding core are located on the second side of the thickness direction of the second winding core, and the negative electrode tab (103) at the lower end of the second winding core is located on the first side of the thickness direction of the second winding core; A fourth winding core is prepared, wherein the upper end of the fourth winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and the lower end of the fourth winding core is provided with a positive electrode tab (102) and a negative electrode tab (103), and all the positive electrode tabs (102) and negative electrode tabs (103) of the fourth winding core are located on the second side of the thickness direction of the fourth winding core; A first winding core, two fourth winding cores and a second winding core are connected in sequence, the positive electrode ear (102) at the lower end of the first winding core is connected to the positive electrode ear (102) at the upper end of the fourth winding core, the negative electrode ear (103) at the lower end of the first winding core is connected to the negative electrode ear (103) at the upper end of the first fourth winding core, the positive electrode ear (102) at the lower end of the first fourth winding core is connected to the positive electrode ear (102) at the upper end of the second fourth winding core, the negative electrode ear (103) at the lower end of the first fourth winding core is connected to the negative electrode ear (103) at the upper end of the second fourth winding core, the positive electrode ear (102) at the lower end of the second fourth winding core is connected to the positive electrode ear (102) at the upper end of the second winding core, and the negative electrode ear (103) at the lower end of the second fourth winding core is connected to the negative electrode ear (103) at the upper end of the second winding core.

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