Battery roll core, battery and battery preparation method

Abstract

The embodiment of the application provides a battery roll core, a battery and a battery preparation method. The battery roll core is formed by winding two pole pieces and a diaphragm arranged between the two pole pieces. One of the two pole pieces is a positive pole piece, and the other is a negative pole piece. At least one of the pole pieces has a plurality of first tab groups and a plurality of second tab groups. The plurality of first tab groups and the plurality of second tab groups are alternately arranged along the length direction of the pole piece. The first tab group includes at least two first tabs arranged at intervals. The second tab group includes at least one second tab. The width of the first tab is different from the width of the second tab. The plurality of first tab groups are located on a first side in the width direction of the battery roll core and are arranged to overlap each other. The plurality of second tab groups are located on a second side in the width direction of the battery roll core and are arranged to overlap each other. The application solves the technical problem of tab misplacement in the tab generation process.

Description

Technical Field

[0001] This application relates to the field of battery core technology, specifically to a battery core, a battery, and a battery preparation method. Background Technology

[0002] In existing technologies, due to the large number of tabs, there are certain manufacturing difficulties in the process. In order to avoid the impact of tab misalignment on the effective welding area, the width of the soft tab is generally designed to be relatively wide, resulting in design redundancy. In addition, for the narrow core, the risk of positive and negative tabs crossing is extremely high. Due to the large number of tabs and small spacing, the current distribution between the tabs is uneven. At the same time, the alignment accuracy of the electrode sheets is required during the manufacturing process, and the problem of adjacent tabs being misaligned due to winding errors or tab width design redundancy is easy to occur.

[0003] There is currently no good solution to the above problems. Summary of the Invention

[0004] This application provides a battery core, a battery, and a battery manufacturing method to at least solve the technical problem of tab misalignment in the existing multi-tab generation process.

[0005] According to one aspect of the embodiments of this application, a battery core is provided. The battery core is formed by winding two electrode sheets and a separator disposed between the two electrode sheets. One electrode sheet is a positive electrode sheet and the other electrode sheet is a negative electrode sheet. At least one electrode sheet has a plurality of first tab groups and a plurality of second tab groups. The plurality of first tab groups and the plurality of second tab groups are alternately arranged along the length direction of the electrode sheet. Each winding layer of the electrode sheet is provided with any one of the first tab groups and the second tab groups. The first tab group includes at least two first tabs arranged at intervals, and the second tab group includes at least one second tab. The widths of the first tabs and the second tabs are different. The plurality of first tab groups are all located on a first side in the width direction of the battery core and are arranged overlapping each other. The plurality of second tab groups are all located on a second side in the width direction of the battery core and are arranged overlapping each other. The first tab groups and the second tab groups are staggered along the width direction of the battery core.

[0006] Furthermore, the first electrode group includes two first electrodes spaced apart, and the second electrode group includes one second electrode, with the widths of the first electrodes and the second electrodes being different.

[0007] Furthermore, the first electrode group includes two first electrodes spaced apart, and the second electrode group includes two second electrodes spaced apart, wherein the widths of the first electrodes and the second electrodes are set differently.

[0008] Furthermore, both electrodes have a first tab group and a second tab group. The first tab groups of the two electrodes are arranged identically, and the second tab groups of the two electrodes are arranged identically. The first tab group and the second tab group of one electrode are located on the first side in the length direction of the battery core to form the positive electrode of the battery core, and the first tab group and the second tab group of the other electrode are located on the second side in the length direction of the battery core to form the negative electrode of the battery core. The positive and negative electrodes are symmetrically arranged about the height center line of the battery core.

[0009] Furthermore, one of the electrode sheets has a first tab group and a second tab group, and the other electrode sheet has a plurality of third tabs. The plurality of third tabs are spaced apart along the length direction of the electrode sheet, and the plurality of third tabs are of the same width. In addition, the plurality of third tabs are overlapped along the width direction of the battery core.

[0010] Furthermore, the width of the first electrode tab is L1, and the width of the second electrode tab is L2, wherein 9mm≤L1≤11mm and 4mm≤L2≤5mm.

[0011] Furthermore, at least one electrode has empty foil areas on both sides in the height direction, and the width of the empty foil area is L3, wherein 5mm≤L3≤10mm.

[0012] According to another aspect of the embodiments of this application, a battery is also provided, the battery including a battery core, the battery core being the aforementioned battery core.

[0013] According to another aspect of the embodiments of this application, a battery manufacturing method is also provided. The battery manufacturing method is used to manufacture the above-mentioned battery and includes the following steps: preparing a positive electrode sheet and a negative electrode sheet, wherein both the positive electrode sheet and the negative electrode sheet have a first tab group and a second tab group, or either the positive electrode sheet or the negative electrode sheet has a first tab group and a second tab group; winding the positive electrode sheet and the negative electrode sheet with a separator and ultrasonically welding them to form a battery core, wherein the head of the positive electrode sheet and the tail of the negative electrode sheet are both attached with protective tape; welding the tabs of the positive electrode sheet and the tabs of the negative electrode sheet respectively, encapsulating the battery core, and adding electrolyte after encapsulation; and processing the battery core using a high-temperature formation process to obtain a battery.

[0014] Further, the preparation of the positive and negative electrode sheets includes the following steps: applying a positive electrode coating to a first substrate using a zebra intermittent double-sided continuous coating method, leaving empty foil areas on both sides of the first substrate, and forming a soft electrode tab by laser die-cutting to obtain a positive electrode sheet; applying a negative electrode coating to a second substrate using a zebra intermittent double-sided continuous coating method, leaving empty foil areas on both sides of the second substrate, and forming a soft electrode tab by laser die-cutting to obtain a negative electrode sheet; wherein, the head of the first substrate is coated using a double-sided continuous coating method.

[0015] Applying the technical solution of this embodiment, the battery core is formed by winding two electrode sheets and a separator disposed between the two electrode sheets. The separator can effectively prevent internal short circuits and maintain the overall stability of the core. By setting multiple first tab groups and multiple second tab groups on one electrode sheet, and the multiple first tab groups and multiple second tab groups are periodically alternately distributed along the length direction of the electrode sheet, the problem of uneven current distribution inside the electrode sheet can be effectively solved by using multiple tabs. At the same time, the widths of the first tabs and the second tabs are different, forming an alternating structure of large and small tabs, which can reduce the processing difficulty of the electrode sheets, battery core, and battery, reduce battery manufacturing requirements, avoid the tab misalignment problem in the production process of existing multi-tab structures, reduce the safety risks caused by tab misalignment, reduce the problem of uneven current distribution inside the electrode sheets during battery discharge, improve the electron transfer process, reduce the temperature rise of the tabs and the temperature inside the battery, effectively reduce the side reactions of the electrolyte, improve the safety of battery use, and improve the cycle life of the battery.

[0016] In this embodiment, multiple first tab groups are located on the first side of the battery core's width direction and overlap each other, while multiple second tab groups are located on the second side of the battery core's width direction and overlap each other. This staggered arrangement of the first and second tab groups ensures a more uniform current path when transmitting between the electrode layers. This battery core solves the problems of tab misalignment and uneven current distribution in existing technologies. During the winding process, the tabs of adjacent layers are spatially staggered, resulting in a uniform stress distribution on the electrode sheets during winding and effectively avoiding the risk of localized overheating. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1 This is a schematic diagram of the structure of a battery core according to an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of an optional positive electrode sheet according to an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of an optional negative electrode sheet according to an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of an optional battery core structure according to an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of an optional positive electrode sheet according to an embodiment of this application;

[0023] Figure 6 This is a schematic diagram of an optional negative electrode sheet according to an embodiment of this application;

[0024] Figure 7 This is a schematic flowchart of an optional battery manufacturing method according to an embodiment of this application;

[0025] Figure 8 This is a schematic diagram of an optional process for preparing a positive electrode and a negative electrode according to an embodiment of this application;

[0026] Figure 9 This is a schematic flowchart of an optional battery manufacturing method according to an embodiment of this application;

[0027] Figure 10 This is a schematic diagram of the structure of a battery core according to an embodiment of this application;

[0028] Figure 11 This is a schematic diagram of the structure of a battery core according to an embodiment of this application.

[0029] The above figures include the following reference numerals:

[0030] 1. Electrode;

[0031] 11. Positive electrode plate; 12. Negative electrode plate;

[0032] 2. Diaphragm;

[0033] 110. First Pole Ear Group;

[0034] 111. First pole ear;

[0035] 120. Second pole ear group;

[0036] 121. Second pole ear;

[0037] 131. Third pole ear. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0042] In existing lithium-ion batteries and other types of batteries, the connection between the electrode and the terminal directly affects overcurrent and heat generation. Multi-tab wound cells have the advantage of high production efficiency, which can effectively improve battery production efficiency. Compared with the traditional single-tab wound cell design, it can effectively improve the current transmission efficiency and reduce the problem of uneven current distribution on the electrode during charging and discharging, which has a good improvement effect on the later use of the battery. However, the design and manufacturing process of the tabs on each layer of electrode is very complex. A certain number of soft tabs can effectively improve the overcurrent effect, but the improvement effect of each tab on the battery rate and heat dissipation performance is not obvious, and the marginal effect is diminishing.

[0043] Each folded tab design significantly improves power performance, but due to its complex structure, it requires adaptive development of related equipment and software. During processing, the large number of tabs presents certain manufacturing challenges. To avoid the impact of tab misalignment on the effective welding area, the width of the soft tab is generally designed to be relatively wide, resulting in design redundancy. In addition, for narrow cores, the risk of positive and negative tabs crossing is extremely high.

[0044] Combination Figures 1 to 6 As shown, an embodiment of this application provides a battery core.

[0045] Specifically, the battery core is formed by winding two electrode sheets 1 and a separator 2 disposed between the two electrode sheets 1. One electrode sheet 1 is a positive electrode sheet, and the other electrode sheet 1 is a negative electrode sheet. At least one electrode sheet 1 has a plurality of first tab groups 110 and a plurality of second tab groups 120. The plurality of first tab groups 110 and the plurality of second tab groups 120 are alternately arranged along the length direction of the electrode sheet 1. Each winding layer of the electrode sheet 1 is provided with any one of the first tab groups 110 and the second tab groups 120. The first tab group 110 includes at least one of the following: The first tab 111 is spaced apart, and the second tab group 120 includes at least one second tab 121. The widths of the first tab 111 and the second tab 121 are different. Multiple first tab groups 110 are located on the first side of the width direction of the battery core and are arranged overlapping each other. Multiple second tab groups 120 are located on the second side of the width direction of the battery core and are arranged overlapping each other. The first tab group 110 and the second tab group 120 are staggered along the width direction of the battery core.

[0046] Applying the technical solution of this embodiment, the battery core is formed by winding two electrode sheets 1 and a separator 2 disposed between the two electrode sheets 1. The separator 2 can effectively prevent internal short circuits and maintain the overall stability of the core. By setting multiple first tab groups 110 and multiple second tab groups 120 on one electrode sheet 1, and the multiple first tab groups 110 and multiple second tab groups 120 are periodically alternately distributed along the length direction of the electrode sheet, the problem of uneven current distribution inside the electrode sheet 1 can be effectively solved by using multiple tabs. At the same time, the widths of the first tabs 111 and the second tabs 121 are different, forming an alternating structure of large and small tabs, which can reduce the processing difficulty of the electrode sheet 1, the battery core, and the battery, reduce the battery manufacturing requirements, avoid the tab misalignment problem in the production process of the existing multi-tab structure, reduce the safety risks caused by tab misalignment, reduce the problem of uneven current distribution inside the electrode sheet during battery discharge, improve the electron transfer process, reduce the temperature rise of the tabs and the temperature inside the battery, effectively reduce the side reactions of the electrolyte, improve the safety of battery use, and improve the cycle life of the battery.

[0047] In this embodiment, multiple first tab groups 110 are located on the first side of the width direction of the battery core and overlap each other, while multiple second tab groups 120 are located on the second side of the width direction of the battery core and overlap each other. The staggered arrangement of the first tab groups 110 and the second tab groups makes the current transmission path more uniform between the electrode layers. This embodiment solves the problems of tab misalignment and uneven current distribution in the prior art. During the winding process, the tabs of adjacent layers are spatially staggered, making the stress distribution on the electrode uniform during the winding process, while effectively avoiding the risk of local overheating. By setting the widths of the first tab 111 and the second tab 121 to be different, the tabs of adjacent winding layers are stacked non-uniformly in the thickness direction, making the current density distribution along the length direction of the electrode more uniform, effectively avoiding the problem of local current concentration in multi-tab batteries.

[0048] The two electrodes 1 of the battery core are positive electrode 11 and negative electrode 12, respectively.

[0049] It should be understood that, in this embodiment, the first tab group 110 and the second tab group 120 are staggered along the width direction of the battery core, meaning that the first tab 111 in the first tab group 110 and the second tab 121 in the second tab group 120 do not overlap.

[0050] In one exemplary embodiment of this application, such as Figure 2 As shown, multiple first tab groups 110 and multiple second tab groups 120 are alternately arranged on the positive electrode sheet 11. After winding, the multiple first tab groups 110 and multiple second tab groups 120 are alternately distributed along the layers of the winding structure. For example, the innermost layer is the first layer, and from the center outwards are the second layer, the third layer, ... the Nth layer. The first first tab group 110 is located in the first layer, the first second tab group 120 is located in the second layer, the second first tab group 110 is located in the third layer, and the second second tab group 120 is located in the fourth layer. Until the last second tab group 120 or the first tab group 110 is located in the Nth layer, it is ensured that each layer is provided with a tab group. Along the outward direction from the center of the winding structure, that is, the width direction of the battery core, the multiple first tab groups 110 of the positive electrode 11 overlap with each other, and the multiple second tab groups 120 of the positive electrode 11 overlap with each other. The second tab 121 in the second tab group 120 does not overlap with the first tab 111 in the first tab group 110, ensuring that the first tab group 110 and the second tab group 120 are misaligned.

[0051] In one exemplary embodiment of this application, such as Figure 3As shown, multiple first tab groups 110 and multiple second tab groups 120 are alternately arranged on the negative electrode sheet 12. After winding, the multiple first tab groups 110 and multiple second tab groups 120 are alternately distributed along the layers of the winding structure. For example, the innermost layer is the first layer, and from the center outwards are the second layer, the third layer, ... the Nth layer. The first second tab group 120 is located in the first layer, the first first tab group 110 is located in the second layer, the second second tab group 120 is located in the third layer, and the second first tab group 110 is located in the fourth layer. Layer, until the last second tab group 120 or the first tab group 110 is located in the Nth layer, to ensure that each layer is provided with a tab group. Along the outward direction from the center of the winding structure, that is, the width direction of the battery core, the multiple first tab groups 110 of the negative electrode sheet 12 overlap with each other, and the multiple second tab groups 120 of the negative electrode sheet 12 overlap with each other, and the second tab 121 in the second tab group 120 does not overlap with the first tab 111 in the first tab group 110, to ensure that the first tab group 110 and the second tab group 120 are misaligned.

[0052] Specifically, the first electrode group 110 includes two first electrodes 111 spaced apart, and the second electrode group 120 includes a second electrode 121. The widths of the first electrodes 111 and the second electrodes 121 are different.

[0053] In this embodiment, the widths of the first tab 111 and the second tab 121 are set differently, making the current path more dispersed in the longitudinal direction and improving the overall conductivity consistency. Since the widths of the first tab 111 and the second tab 121 are different, the total thickness of the welded area after stacking is significantly reduced, effectively alleviating the phenomenon of local heat accumulation and current density concentration caused by the stacking of tab layers. At the same time, the interval setting improves the bending resistance of the tabs and makes them less prone to breakage.

[0054] Specifically, the first electrode group 110 includes two first electrodes 111 spaced apart, and the second electrode group 120 includes two second electrodes 121 spaced apart, wherein the widths of the first electrodes 111 and the second electrodes 121 are different.

[0055] In this embodiment, by setting the width of the first electrode 111 and the width of the second electrode 121 to be different, the local accumulation thickness of the overlapping area is effectively dispersed, avoiding the problem of excessive welding interface thickness and stress concentration caused by the uniform width. By setting the first electrode 111 and the second electrode 121 alternately, bending stress can be effectively dispersed, greatly reducing the risk of fatigue damage at the root of the electrode.

[0056] It should be noted that the number of first electrodes 111 in the first electrode group 110 and the number of second electrodes 121 in the second electrode group 120 can be adjusted as needed. For example, the number can be set to two, three, four, five, etc.

[0057] Specifically, both electrode sheets 1 have a first tab group 110 and a second tab group 120. The first tab groups 110 of the two electrode sheets 1 are arranged identically, and the second tab groups 120 of the two electrode sheets 1 are arranged identically. The first tab group 110 and the second tab group 120 of one electrode sheet 1 are located on the first side in the length direction of the battery core to form the positive electrode of the battery core. The first tab group 110 and the second tab group 120 of the other electrode sheet 1 are located on the second side in the length direction of the battery core to form the negative electrode of the battery core. The positive electrode and the negative electrode are symmetrically arranged about the height center line of the battery core.

[0058] In this embodiment, by symmetrically arranging the positive and negative electrodes about the height centerline of the battery core, the overlapping area of ​​the positive and negative electrode tabs in the width direction after winding is ensured to be evenly distributed. This balances the mass and stiffness of the positive and negative electrodes in the width direction of the core, effectively eliminating local stress concentration and heat accumulation caused by asymmetrical electrode tab arrangement. It ensures that the heat generation and heat dissipation paths in the positive and negative electrode tab areas are consistent, while also ensuring uniform pressure distribution between each electrode tab layer during welding. This avoids electrochemical imbalance between the positive and negative electrodes and greatly improves the thermal stability of the battery.

[0059] In one exemplary embodiment of this application, such as Figures 1 to 3 As shown, the two electrodes 1 are a positive electrode 11 and a negative electrode 12, respectively. Both the positive electrode 11 and the negative electrode 12 are provided with multiple first electrode tab groups 110 and multiple second electrode tab groups 120. The number of first electrode tabs 111 in the first electrode tab group 110 of the positive electrode 11 and the negative electrode 12 is the same, and the number of second electrode tabs 121 in the second electrode tab group 120 of the positive electrode 11 and the negative electrode 12 is the same.

[0060] Furthermore, one of the electrode sheets 1 has a first tab group 110 and a second tab group 120, and the other electrode sheet 1 has a plurality of third tabs 131. The plurality of third tabs 131 are spaced apart along the length direction of the electrode sheet 1, and the plurality of third tabs 131 are arranged with the same width. In addition, the plurality of third tabs 131 are overlapped along the width direction of the battery core.

[0061] In this embodiment, multiple third tabs 131 are spaced apart along the length of the electrode sheet 1, and the width of the multiple third tabs 131 is the same, which improves the coverage of the negative electrode active material and effectively avoids current concentration and local temperature rise caused by the asymmetry of the positive and negative tab structures. By overlapping multiple third tabs 131, the contact resistance of the negative electrode tab can be significantly reduced, and stress concentration at the welding point can be avoided to prevent cracking. This makes the current distribution of the entire battery core more balanced and improves the consistency and thermal stability of the battery cell.

[0062] In one exemplary embodiment of this application, such as Figure 4 , Figure 5 , Figure 6 , Figure 11 As shown, in a battery core, the positive electrode 11 has a first tab group 110 and a second tab group 120. The first tab group 110 includes two first tabs 111, and the second tab group 120 includes two second tabs 121. The negative electrode 12 has multiple third tabs 131. After winding, the first tab group 110 and the second tab group 120 of the positive electrode 11 are both located on the first side in the length direction of the battery core, forming the positive electrode of the battery core. The multiple third tabs 131 of the negative electrode 12 are both located on the second side in the length direction of the battery core, forming the negative electrode of the battery core.

[0063] Preferably, the width of the third electrode tab 131 can be set between 4mm and 5mm, for example, it can be 4mm, 4.2mm, 4.5mm, 4.7mm, or 5mm.

[0064] Furthermore, the width of the first electrode 111 is L1, and the width of the second electrode 121 is L2, wherein 9mm≤L1≤11mm and 4mm≤L2≤5mm.

[0065] In this embodiment, by setting the width of the first tab 111 to the range of 9mm to 11mm, the stress at the root of the first tab 111 is dispersed during winding, avoiding fatigue fracture of the tab. Multiple first tabs 111 form a welded layer with uniform thickness and stable structure in the overlapping area, which can carry a certain amount of continuous current. Setting the width of the second tab 121 to the range of 4mm to 5mm reduces the resistance of the negative electrode. The specific width range of the first tab 111 and the second tab 121 effectively avoids poor welding and local resistance increase caused by the thickness fluctuation of the tab stack.

[0066] Specifically, L1 can be 9mm, 9.5mm, 10mm, 10.5mm, or 11mm, and L2 can be 4mm, 4.2mm, 4.5mm, 4.7mm, or 5mm.

[0067] Furthermore, at least one electrode 1 has empty foil areas on both sides in the height direction, and the width of the empty foil area is L3, wherein 5mm≤L3≤10mm.

[0068] In this embodiment, by setting empty foil areas on both sides of at least one electrode 1 in the height direction, stable support can be provided for the edge of the electrode tab during the winding process of the electrode 1, effectively suppressing the electrode tab from shifting or stacking too thickly during stacking, avoiding uneven heat flow distribution during welding, and setting the width of the empty foil area between 5mm and 10mm, so that the root of the electrode tab transitions smoothly, reducing the stress gradient and avoiding stress concentration.

[0069] Specifically, L3 can be 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0070] This application also provides a battery, including a battery core, wherein the battery core is the battery core described above.

[0071] By applying the technical solution of this embodiment, multiple first tab groups 110 and multiple second tab groups 120 are alternately arranged along the length direction of the electrode sheet, so that the current path is more evenly distributed along the length direction of the electrode sheet, reducing the local current density and making the charge distribution of the entire battery cell more balanced. By setting the width of the first tab 111 and the width of the second tab 121 differently, the staggered arrangement of the first tab group 110 and the second tab group makes the current path more uniform when it is transmitted between the electrode layers, and at the same time significantly reduces the local temperature rise of the tabs, optimizes the temperature uniformity inside the battery cell and the thermal stability of the battery cell, thereby improving the overall structural stability and cycle life of the battery.

[0072] like Figure 7 As shown in the figure, this application embodiment also provides a battery manufacturing method, which is used to manufacture the above-mentioned battery, including the following steps:

[0073] Step S100: Prepare a positive electrode sheet and a negative electrode sheet, wherein both the positive electrode sheet and the negative electrode sheet have a first tab group and a second tab group, or either the positive electrode sheet or the negative electrode sheet has a first tab group and a second tab group.

[0074] In step S200, the positive electrode sheet, negative electrode sheet and separator are wound together and ultrasonically welded to form a battery core. Protective tape is attached to the head of the positive electrode sheet and the tail of the negative electrode sheet.

[0075] Step S300: After welding the tabs of the positive electrode and the tabs of the negative electrode respectively, the battery core is packaged and electrolyte is added after the packaging is completed.

[0076] Step S400: The battery core is processed using a high-temperature formation process to obtain the battery.

[0077] In step S100, by setting alternating first tab groups and second tab groups on the positive and negative electrode plates, and making the multiple first tabs in the first tab group and the second tabs in the second tab group have different widths, the local concentration of the tab stack thickness is effectively reduced, and the heat conduction uniformity of the welding area is improved.

[0078] In step S200, the positive electrode, negative electrode and separator are wound together and ultrasonically welded to form a battery core. Ultrasonic welding makes the welding area cleaner and free from pollution. Protective tape is attached to the head of the positive electrode and the tail of the negative electrode to prevent electrode displacement during the winding process and improve the connection reliability between the tabs. At the same time, the protective tape only covers the head and tail of the electrode and is physically isolated from the welding area.

[0079] In step 300, the battery core is encapsulated after the tabs of the positive electrode and the tabs of the negative electrode are welded together. After completion, electrolyte is added. When the welding is completed, the position of the tabs is fixed and the welding area has formed physical isolation. After encapsulation, electrolyte is added to prevent the electrolyte from directly contacting the metal solder joints, to prevent the solder joints from being corroded, and to prevent short circuits caused by misalignment of the tabs.

[0080] In step S400, the battery core is processed by a high-temperature formation process to obtain the battery. The high-temperature formation process can improve the diffusion rate of lithium ions, promote electrolyte decomposition, enhance electrolyte fluidity, and reduce electrolyte viscosity, thereby improving the charging and discharging efficiency of the battery.

[0081] Based on steps S100 to S400, by setting alternating first and second tab groups on the positive and negative electrode sheets, the positive electrode sheet, negative electrode sheet, and separator are wound and then ultrasonically welded to form a battery core. After welding the tabs of the positive and negative electrode sheets, the battery core is encapsulated, then electrolyte is added, and finally the battery core is processed by a high-temperature formation process to obtain the battery. This improves the reliability of the connection between the tabs. Finally, after encapsulation and high-temperature formation, the current distribution inside the battery is more uniform, the battery temperature rise is reduced, and the battery cycle stability is improved.

[0082] Specifically, such as Figure 8 As shown, in step S100, the positive electrode and the negative electrode are prepared, including the following steps:

[0083] Step S101: The positive electrode coating is applied to the first substrate using the zebra intermittent double-sided continuous coating method, and empty foil areas are reserved on both sides of the first substrate. The soft electrode tab is formed by laser die cutting to obtain the positive electrode sheet 11.

[0084] Step S102: The negative electrode coating is applied to the second substrate using the zebra intermittent double-sided continuous coating method, and empty foil areas are reserved on both sides of the second substrate. The soft electrode tab is formed by laser die cutting to obtain the negative electrode sheet 12.

[0085] The head of the first substrate is coated with a double-sided continuous coating.

[0086] In steps S101 to S102, a positive electrode coating is applied to the first substrate using a zebra intermittent double-sided continuous coating method, forming alternating coated and uncoated areas on the aluminum foil. This ensures a clear boundary between the tab area and the active material area. By reserving empty foil areas on both sides of the first substrate, the obstruction of the current path by adhesives and other substances is avoided, improving the conductivity of the tabs. Positive and negative electrode sheets are obtained by laser die-cutting. Laser die-cutting is a non-contact processing method, resulting in no metal debris at the edges of the tabs. The laser-cut tabs have high flatness and uniform thickness, significantly improving the welding yield. By applying a double-sided continuous coating to the head of the first substrate, the thickness distribution in the electrode head area becomes more uniform, ensuring the alignment of the electrode sheets during winding.

[0087] Embodiments of this application also provide a novel electrode-wound multi-stage lithium-ion battery cell.

[0088] Specifically, the novel multi-level lithium-ion battery cell with winding tabs includes a core formed by winding a positive electrode 11, a negative electrode 12, and a separator 2. The arrangement of the core tabs can be either a differential arrangement or a symmetrical arrangement.

[0089] Furthermore, the differential arrangement structure is as follows: for both the positive and negative electrodes, the large and small tabs on both sides AB are identical in shape (in this embodiment, the wider tab is the large tab, and the narrower tab is the small tab), the large and small tabs of the positive electrode are arranged alternately, and the number of tabs on the positive electrode is twice the number of tabs on the negative electrode, wherein, as reference Figure 10 As shown, AB refers to the two opposite sides of the battery core in the width direction, centered on the geometric center of the battery core. Both sides A and B have multiple winding layers. Taking the positive electrode as an example, side A has both large and small tabs, and side B also has both large and small tabs.

[0090] Furthermore, the symmetrical arrangement structure is as follows: for the positive and negative electrodes, the shapes on both sides AB are complementary, and the large and small tabs of the positive and negative electrodes are located on opposite sides. For example... Figure 10 As shown, the large tabs of the positive electrode 11 are all located on side B, and the small tabs of the positive electrode 11 are all located on side A, so as to form a complementary structure on both sides AB. The large tabs of the negative electrode 12 are all located on side A, and the small tabs of the negative electrode 12 are all located on side B, so as to form a complementary structure on both sides AB.

[0091] Preferably, the electrode structure allows for interchangeable positions of the large and small electrodes, and the width of the large and small electrodes can be adjusted according to the moving width of the winding core.

[0092] Preferably, the number of tabs is an integer multiple of the number of electrode layers wound, and they are evenly distributed on both sides of the core.

[0093] Preferably, the negative electrode sheet is a double-sided continuously coated double-sided material structure or a double-sided intermittent material for both positive and negative electrodes, or one of them is a single-sided intermittent material;

[0094] Specifically, this application provides an embodiment 1 of a multi-level lithium-ion battery cell with electrode loops wound around the electrodes, such as... Figures 1 to 3 As shown, this is suitable for conventional winding structures. The tabs are symmetrically arranged, with the large tab of the positive electrode located on the left side of the winding core and the corresponding large tab of the negative electrode located on the right side of the winding core, presenting a symmetrical structure. There is a 0.5mm gap between the large and small tabs inside the positive electrode tab, which can avoid the problem of local excessive thickness during subsequent welding.

[0095] Furthermore, the winding requirements are as follows:

[0096] 1) The positive electrode head inside the core is a double-sided continuously coated electrode sheet, and the negative electrode head is a continuously coated electrode sheet;

[0097] 2) The alignment error of each electrode layer is less than 0.5mm, using a clockwise rotation.

[0098] Specifically, such as Figure 9 As shown, the battery fabrication method includes the following steps:

[0099] Step S1, electrode preparation.

[0100] Positive electrode 11: The coating is carried out using the zebra intermittent double-sided continuous coating method. A 10mm wide empty foil area is reserved on both sides of the positive electrode 11. The soft electrode tab is formed by laser die cutting. The positive electrode 11 consists of a positive electrode material area and aluminum foil. The positive electrode 11 is an electrode with two 10mm and one 4.5mm electrode tabs arranged in a cross pattern.

[0101] Negative electrode 12: The coating is carried out using the zebra intermittent double-sided continuous coating method. A 5-10mm wide empty foil area is reserved on both sides of the negative electrode 12. The soft electrode tab is formed by laser die cutting. The negative electrode 12 consists of a positive electrode material area and aluminum foil. The negative electrode 12 is an electrode with two 10mm and one 4.5mm electrode tabs arranged in a cross pattern.

[0102] Step S2, winding preparation. The positive and negative electrode sheets are stacked with a separator and wound together. 5mm protective tape needs to be attached to the head of the positive electrode sheet and the tail of the negative electrode sheet to fix them and prevent lithium plating. They are then welded together using ultrasonic welding to assemble them into a core.

[0103] Step S3: After welding the core and the tabs, seal them with an aluminum-plastic film, and then add electrolyte.

[0104] Step S4: The final multi-level lithium-ion battery is obtained through a high-temperature formation process.

[0105] Specifically, this application provides an embodiment 2 of a multi-level lithium-ion battery cell with electrode loops wound around the electrodes, such as... Figures 4 to 6 As shown, this is suitable for conventional winding structures. The tabs are symmetrically arranged, with the positive electrode tab located on the left side of the core and the corresponding negative electrode tab located on the right side of the core, presenting an asymmetrical structure. There is a 0.5mm gap between the large and small tabs inside the positive electrode tab, which can avoid the problem of local excessive thickness during subsequent welding.

[0106] Furthermore, the winding requirements are as follows:

[0107] 1) The positive electrode head inside the core is a double-sided continuously coated electrode sheet, and the negative electrode head is a continuously coated electrode sheet;

[0108] 2) The alignment error of each electrode layer is less than 0.5mm, using a clockwise rotation.

[0109] Specifically, the battery manufacturing method includes the following steps:

[0110] Step S1, electrode preparation.

[0111] Positive electrode sheet: The coating is carried out using the zebra intermittent double-sided continuous coating method. A 5-10mm wide empty foil area is reserved on both sides of the positive electrode sheet 11. The soft electrode tabs are formed by laser die cutting. The positive electrode sheet 11 consists of a positive electrode material area and aluminum foil. The positive electrode sheet is an electrode sheet with two 10mm and two 4.5mm electrode tabs arranged in a cross pattern.

[0112] Negative electrode sheet: The negative electrode sheet 12 is coated using the zebra intermittent double-sided continuous coating method. A 5-10mm wide empty foil area is reserved on both sides of the negative electrode sheet 12. The soft electrode tab is formed by laser die cutting. The negative electrode sheet 12 consists of a positive electrode material area and aluminum foil. All the negative electrode sheets 12 have 4.5mm tabs.

[0113] Step S2, winding preparation. The positive and negative electrode sheets are stacked with a separator and wound together. 5mm protective tape needs to be attached to the head of the positive electrode sheet and the tail of the negative electrode sheet to fix them and prevent lithium plating. They are then welded together by ultrasonic welding to assemble them into a core.

[0114] Step S3: After welding the core and the tabs, seal them with an aluminum-plastic film, and then add electrolyte.

[0115] Step S4: The final multi-level lithium-ion battery is obtained through a high-temperature formation process.

[0116] The technical solution using the embodiments of this application has the following advantages:

[0117] 1) The special treatment of the soft tabs can effectively uniformize the current distribution, and the transmission rate from the electrode to the terminal is significantly improved, providing a more effective transmission means for subsequent high-power battery charging and discharging.

[0118] 2) Through structural optimization, it is possible to better meet the current complex and ever-changing application needs of lithium batteries, and to provide lithium batteries with special structures;

[0119] 3) The reasonable distribution of soft tabs can effectively improve the cycle life of the battery, reduce the problem of uneven heat dissipation during battery use, and play an irreplaceable role in improving the internal lithium-ion conduction of the cell and improving the temperature consistency of the cell under low temperature conditions.

[0120] 4) The differentiated design of the soft electrode tabs can effectively reduce the risk of internal short circuits, while significantly reducing the welding thickness of the soft electrode tabs and improving the quality and reliability of the welding.

[0121] 5) Differentiated tab design can effectively reduce the risk of tab sagging and also help improve the top space of the battery cell.

[0122] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0123] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0124] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0125] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0126] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0127] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0128] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0129] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A battery winding core, characterized in that, The battery core is formed by winding two electrode sheets (1) and a separator (2) disposed between the two electrode sheets (1), wherein one electrode sheet (1) is a positive electrode sheet and the other electrode sheet (1) is a negative electrode sheet. At least one of the electrode sheets (1) has a plurality of first electrode tab groups (110) and a plurality of second electrode tab groups (120), the plurality of first electrode tab groups (110) and the plurality of second electrode tab groups (120) are alternately arranged along the length direction of the electrode sheet (1), and each winding layer of the electrode sheet (1) is provided with any one of the first electrode tab groups (110) and the second electrode tab groups (120); The first tab group (110) includes at least two first tabs (111) spaced apart, and the second tab group (120) includes at least one second tab (121). The widths of the first tabs (111) and the second tabs (121) are different. Multiple first tab groups (110) are located on a first side in the width direction of the battery core and are arranged overlapping each other. Multiple second tab groups (120) are located on a second side in the width direction of the battery core and are arranged overlapping each other. In this configuration, the first tab group (110) and the second tab group (120) are staggered along the width direction of the battery core.

2. The battery core according to claim 1, characterized in that, The first electrode group (110) includes two first electrodes (111) spaced apart, and the second electrode group (120) includes one second electrode (121). The width of the first electrode (111) is different from the width of the second electrode (121).

3. The battery core according to claim 1, characterized in that, The first electrode group (110) includes two first electrodes (111) spaced apart, and the second electrode group (120) includes two second electrodes (121) spaced apart. The widths of the first electrodes (111) and the second electrodes (121) are different.

4. The battery core according to claim 2, characterized in that, Both of the electrode plates (1) have a first tab group (110) and a second tab group (120). The first tab groups (110) of the two electrode plates (1) are arranged identically, and the second tab groups (120) of the two electrode plates (1) are arranged identically. The first tab group (110) and the second tab group (120) of one electrode plate (1) are located on a first side in the length direction of the battery core to form the positive electrode of the battery core. The first tab group (110) and the second tab group (120) of the other electrode plate (1) are located on a second side in the length direction of the battery core to form the negative electrode of the battery core. The positive electrode and the negative electrode are symmetrically arranged about the height center line of the battery core.

5. The battery core according to claim 2, characterized in that, One of the electrode sheets (1) has a first tab group (110) and a second tab group (120), and the other electrode sheet (1) has a plurality of third tabs (131). The plurality of third tabs (131) are spaced apart along the length direction of the electrode sheet (1), and the plurality of third tabs (131) are of the same width. Furthermore, the plurality of third tabs (131) are overlapped along the width direction of the battery core.

6. The battery core according to claim 2 or 3, characterized in that, The width of the first electrode tab (111) is L1, and the width of the second electrode tab (121) is L2, wherein 9mm≤L1≤11mm and 4mm≤L2≤5mm.

7. The battery core according to claim 1, characterized in that, At least one of the electrode sheets (1) has empty foil areas on both sides in the height direction, and the width of the empty foil areas is L3, wherein 5mm≤L3≤10mm.

8. A battery, characterized in that, The battery includes a battery core, which is the battery core according to any one of claims 1-7.

9. A method for manufacturing a battery, characterized in that, The battery preparation method is used to prepare the battery of claim 8, and includes the following steps: Prepare a positive electrode sheet and a negative electrode sheet, wherein the positive electrode sheet and the negative electrode sheet each have a first tab group and a second tab group, or either the positive electrode sheet or the negative electrode sheet has a first tab group and a second tab group; The positive electrode, the negative electrode, and the separator are wound together and ultrasonically welded to form a battery core. Protective tape is attached to the head of the positive electrode and the tail of the negative electrode. After welding the tabs of the positive electrode and the tabs of the negative electrode respectively, the battery core is packaged, and electrolyte is added after the packaging is completed. The battery core is processed using a high-temperature formation process to obtain the battery.

10. The battery manufacturing method according to claim 9, characterized in that, The preparation of positive and negative electrode plates includes the following steps: The positive electrode coating is applied to the first substrate using the zebra intermittent double-sided continuous coating method, and empty foil areas are reserved on both sides of the first substrate. The soft electrode tab is formed by laser die-cutting to obtain the positive electrode sheet. The negative electrode coating is applied to the second substrate using the zebra intermittent double-sided continuous coating method, and empty foil areas are reserved on both sides of the second substrate. The soft electrode tab is formed by laser die-cutting to obtain the negative electrode sheet. The head of the first substrate is coated with a double-sided continuous coating.

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