A soft-pack cylindrical sodium ion battery

Abstract

The present application relates to the field of sodium ion batteries, and in particular to a soft-pack cylindrical sodium ion battery, which comprises a cell assembly, a positive current collector, a negative current collector, a positive cover, a negative cover, a first fixing member, a second fixing member, a positive electrode column and a negative electrode column, wherein the cell assembly comprises a cell body, a positive electrode tab group and a negative electrode tab group, the positive electrode tab group is arranged on the positive terminal of the cell body, and the negative electrode tab group is arranged on the negative terminal of the cell body, the sizes of the first fixing member and the second fixing member can be matched according to the overcurrent requirements of the battery, and the assembly is more convenient and efficient, the material of the positive electrode cover and / or the negative electrode cover is plastic, and setting the material of the positive electrode cover and / or the negative electrode cover to plastic reduces the weight of the structural parts in the cylindrical battery, thereby greatly improving the mass energy density of the battery.

Description

Technical Field

[0001] The present application relates to the field of sodium ion batteries, and in particular to a soft-package cylindrical sodium ion battery. Background Art

[0002] At present, lithium-ion batteries occupy the core position of power batteries. At the same time, lithium-ion batteries are also facing great challenges, such as the increasing shortage of lithium resources and the continuous rise in upstream material prices. Sodium-ion batteries can use the sodium ions in the process of deintercalation between the positive and negative electrodes to achieve charging and discharging. Moreover, the reserves of sodium resources are far more abundant than lithium batteries and the cost is much lower than lithium. Therefore, sodium-ion batteries are expected to replace lithium-ion batteries and become a new generation of electrochemical system.

[0003] Sodium-ion batteries mainly include cylindrical batteries, soft-pack batteries and square hard-shell batteries. Among them, cylindrical batteries have the advantages of high automation, mature technology and good consistency, and are widely used in the field of new energy vehicles. With the rapid development of the field of new energy vehicles, the requirements for the energy density, power density, rate performance and safety of sodium-ion batteries are getting higher and higher. However, since the weight of the structural parts of the current cylindrical sodium-ion battery accounts for a large proportion of the total weight of the battery, the improvement space of the mass energy density of the cylindrical battery is limited, which limits its application. Summary of the invention

[0004] In view of the above problems of the prior art, the present application provides a soft-pack cylindrical sodium-ion battery, which reduces the total weight of the battery occupied by the structural parts, thereby greatly improving the mass energy density of the cylindrical battery. The specific technical solution is as follows:

[0005] The present application provides a soft-pack cylindrical sodium-ion battery, comprising: a battery cell assembly, comprising a battery cell body, a positive electrode tab group and a negative electrode tab group, wherein the positive electrode tab group is arranged on the positive terminal of the battery cell body, the negative electrode tab group is arranged on the negative terminal of the battery cell body, and the positive electrode tab group and / or the negative electrode tab group have a symmetrical fan-shaped structure;

[0006] A positive electrode current collecting plate, covering the exposed surface of the positive electrode tab group;

[0007] A negative electrode current collecting plate, covering the exposed surface of the negative electrode tab group;

[0008] A positive electrode cover plate, which is covered on the positive electrode current collecting disk;

[0009] A negative electrode cover plate, which is covered on the negative electrode current collecting plate;

[0010] The material of the positive electrode cover plate and / or the negative electrode cover plate is plastic;

[0011] The battery further comprises a first fixing member, the positive current collecting plate is provided with a positive electrode column in a direction along the axis of the battery cell assembly, the positive electrode cover is provided with a first through hole in a direction along the axis of the battery cell assembly, and the positive electrode column is connected to the first fixing member after passing through the first through hole;

[0012] The battery also includes a second fixing member, the negative current collecting plate is provided with a negative electrode column in the direction along the axis of the battery cell assembly, the negative electrode cover is provided with a second through hole in the direction along the axis of the battery cell assembly, and the negative electrode column is connected to the second fixing member after passing through the second through hole.

[0013] In a possible implementation manner, the positive electrode tab group and the negative electrode tab group both have a symmetrical fan-shaped structure, and a preset angle is formed between the center line of the symmetrical fan-shaped structure of the positive electrode tab group and the center line of the symmetrical fan-shaped structure of the negative electrode tab group, and the preset angle ranges from 30° to 90°;

[0014] In a possible implementation manner, a center line of the symmetrical fan-shaped structure of the positive electrode tab group is orthogonal to a center line of the symmetrical fan-shaped structure of the negative electrode tab group.

[0015] In a possible implementation manner, the battery further includes a shell, the shell is wrapped around the outer surface of the battery core assembly, and the shell is made of an aluminum-plastic film.

[0016] In a possible implementation manner, an edge of the shell close to the positive electrode cover plate is flush with an outer edge of the positive electrode cover plate, and an edge of the shell close to the negative electrode cover plate is flush with an outer edge of the negative electrode cover plate.

[0017] In a possible implementation, the positive electrode tab group includes a fan-shaped first positive electrode tab group and a fan-shaped second positive electrode tab group, the negative electrode tab group includes a fan-shaped first negative electrode tab group and a fan-shaped second negative electrode tab group, the first positive electrode tab group and the second positive electrode tab group are symmetrically arranged along the radial direction of the battery cell body, and the first negative electrode tab group and the second negative electrode tab group are symmetrically arranged along the radial direction of the battery cell body.

[0018] In a possible implementation manner, the first positive electrode tab group includes a plurality of arc-shaped positive electrode tabs, the plurality of positive electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the sector; the first negative electrode tab group includes a plurality of negative electrode tabs, the plurality of negative electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the sector.

[0019] In a possible implementation manner, the battery satisfies at least one of the following characteristics:

[0020] The arc length setting of the positive electrode ear satisfies the following formula: (2×π×r1) / x1≤W1≤(2×π×r1) / y1, wherein W1 is the arc length of the positive electrode ear, r1 is the arc radius of the positive electrode ear, the value range of x1 is 2 to 8, the value range of y1 is 2 to 8, and y1<x1.

[0021] The arc length setting of the negative electrode ear satisfies the following formula: (2×π×r2) / x2≤W2≤(2×π×r2) / y2, wherein W2 is the arc length of the negative electrode ear, r2 is the arc radius of the negative electrode ear, the value range of x2 is 2 to 8, the value range of y2 is 2 to 8, and y2<x2.

[0022] In a possible implementation manner, the battery satisfies at least one of the following characteristics:

[0023] The positive electrode cover plate is provided with a first thickened area and a first concave area, the first thickened area protrudes from the inner surface of the positive electrode cover plate, the first concave area is recessed in the inner surface of the positive electrode cover plate, and the positive current collector is embedded in the first concave area; the positive electrode tab group protrudes from the surface of the battery body, a first vacant area is formed between the first positive electrode tab group and the second positive electrode tab group, and the first thickened area is embedded in the first vacant area;

[0024] The negative electrode cover plate is provided with a second thickened area and a second concave area, the second thickened area protrudes from the inner surface of the negative electrode cover plate, the second concave area is recessed into the inner surface of the negative electrode cover plate, and the negative current collecting plate is embedded in the second concave area; the negative electrode tab group protrudes from the surface of the battery cell body, a second vacant area is formed between the first negative electrode tab group and the second negative electrode tab group, and the second thickened area is embedded in the second vacant area.

[0025] In a possible implementation manner, the battery satisfies at least one of the following characteristics:

[0026] The depression depth of the first concave area is greater than or equal to the protrusion height of the positive electrode tab group protruding from the surface of the battery cell body;

[0027] The depression depth of the second inner concave area is greater than or equal to the protrusion height of the negative electrode tab group protruding from the surface of the battery cell body.

[0028] Based on the above technical solution, this application has the following beneficial effects:

[0029] The soft-pack cylindrical sodium-ion battery in the present application includes a battery cell assembly, wherein the battery cell assembly includes a battery cell body, a positive electrode tab group and a negative electrode tab group, the positive electrode tab group is arranged on the positive terminal of the battery cell body, and the negative electrode tab group is arranged on the negative terminal of the battery cell body, the positive electrode tab group and the negative electrode tab group have a symmetrical fan-shaped structure, and the positive electrode tab group and the negative electrode tab group are arranged at both ends of the battery cell body, which effectively reduces the space requirement of the tabs inside the battery cell, thereby improving the energy density of the battery, and also avoiding the occurrence of battery short circuit. On this basis, the present application arranges the positive electrode tab group and / or the negative electrode tab group into a symmetrical fan-shaped structure. Compared with the traditional straight line or circular structure, the fan-shaped structure can increase the surface area in the same space. When the tabs are arranged in a fan-shaped structure, the surface area of ​​the tabs can be increased. When arranged, the tip can fit more compactly on the current collector, and the base is expanded to increase the contact area with the current collector. This arrangement can effectively reduce the contact resistance, and also improve the battery's overcurrent capability and current transmission efficiency, while also being beneficial to the dispersion of heat, further improving the battery's safety and life, and also improving the battery's mass energy density. Compared with the prior art in which the pole ear group is a plurality of groups of symmetrical fan-shaped structures, the pole ear group of the present application is only a group of symmetrical fan-shaped structures, with a simple preparation process and lower cost, better reproducibility, and lower mass of the formed battery cell assembly, further improving the battery's mass energy density. The battery of the present application also includes a positive current collector plate, a negative current collector plate, a positive cover plate and a negative cover plate, and the positive current collector plate is covered on the positive electrode The exposed surface of the pole lug group, the negative electrode current collecting plate is covered on the exposed surface of the negative electrode pole lug group, and the positive electrode current collecting plate and the negative electrode current collecting plate are respectively provided on the exposed surface of the positive electrode pole lug group and the exposed surface of the negative electrode pole lug group, which can effectively collect the current in the battery cell assembly and transmit it to the external circuit, reduce the internal resistance, and improve the current collection efficiency. The positive electrode cover plate is further provided on the positive electrode current collecting plate, and the negative electrode cover plate is provided on the negative electrode current collecting plate, wherein the cover plate can provide additional mechanical support, enhance the overall structural stability of the current collecting plate, and at the same time simplify the assembly steps, thereby improving the production efficiency and consistency of the battery. On the basis of the above, by setting the material of the positive electrode cover plate and / or the negative electrode cover plate to plastic, not only the weight of the structural parts in the cylindrical battery is reduced, but also the battery life is greatly improved. The mass energy density of the battery has expanded the application field of cylindrical batteries, especially in the fields of new energy vehicles, and has significantly reduced the preparation cost of the battery. The present application further arranges a first fixing member and a positive electrode column, a second fixing member and a negative electrode column, so that the positive electrode column can pass through the first through hole of the positive electrode current disk and then be connected to the first fixing member, and the negative electrode column can pass through the second through hole of the negative electrode current disk and then be connected to the second fixing member, thereby enhancing the mechanical strength of the battery, reducing the loosening or damage of the connection caused by vibration or impact during use, and improving the stability and safety of the battery. The sizes of the first fixing member and the second fixing member of the present application can be matched according to the overcurrent requirements of the battery, and the manufacturer can match the sizes of different fixing members according to the different rates and currents of the battery.And the assembly is more convenient and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 It is a schematic diagram of the structure of a soft-pack cylindrical sodium-ion battery;

[0032] Figure 2 This is a schematic diagram of the structure of a soft-pack cylindrical sodium-ion battery after removing the shell;

[0033] Figure 3 It is a schematic diagram of the structure of the battery core;

[0034] Figure 4 It is a schematic diagram of the structure of the positive electrode tab group of the battery cell body;

[0035] Figure 5 It is a schematic diagram of the structure of the negative electrode tab group of the battery cell body;

[0036] Figure 6 It is a schematic diagram of the structure of a soft-pack cylindrical sodium-ion battery;

[0037] Figure 7 It is a schematic diagram of the structure of a soft-pack cylindrical sodium-ion battery;

[0038] Figure 8 It is a schematic diagram of the structure of a soft-pack cylindrical sodium-ion battery;

[0039] Fig. 9 Schematic diagram of the structure of the positive electrode cover;

[0040] Fig.10 Schematic diagram of the structure of the positive electrode cover;

[0041] Fig.11 is a schematic diagram of the structure of the negative electrode cover;

[0042] Fig.12 Schematic diagram of the structure of the negative electrode cover.

[0043] In the figure: 1-battery cell assembly, 11-battery cell body, 12-positive electrode tab group, 121-first positive electrode tab group, 122-second positive electrode tab group, 13-negative electrode tab group, 131-first negative electrode tab group, 132-second negative electrode tab group, 14-positive current collecting plate, 141-positive electrode column, 15-negative electrode current collecting plate, 151-negative electrode column, 16-positive electrode cover, 161-first thickened area, 162-first concave area, 17-negative electrode cover, 171-second thickened area, 172-second concave area, 18-shell, 19-first fixing member, 20-second fixing member. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] For the following defined terms, these definitions shall apply unless a different definition is given in the claims or elsewhere in this specification. All numerical values, whether or not explicitly indicated, are defined herein as modified by the term "about". The term "about" generally refers to a numerical range that a person of ordinary skill in the art considers to be equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A numerical range indicated by a lower value and a higher value is defined to include all numerical values ​​included in the numerical range and all subranges included in the numerical range.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0047] The following describes a soft-pack cylindrical sodium-ion battery provided in an embodiment of the present application, including a battery cell assembly 1, including a battery cell body 11, a positive electrode tab group 12 and a negative electrode tab group 13, the positive electrode tab group 12 is arranged on the positive end of the battery cell body 11, and the negative electrode tab group 13 is arranged on the negative end of the battery cell body 11, the positive electrode tab group 12 and / or the negative electrode tab group 13 have a symmetrical fan-shaped structure, a positive electrode current collecting plate 14, which is covered on the exposed surface of the positive electrode tab group 12, and a negative electrode current collecting plate 15, which is covered on the negative electrode tab. The exposed surface of the ear group 13, the positive electrode cover plate 16, is covered on the positive electrode collector plate 14, and the negative electrode cover plate 17 is covered on the negative electrode collector plate 15. The material of the positive electrode cover plate 16 and / or the negative electrode cover plate 17 is plastic. The battery also includes a first fixing member 19. The positive electrode collector plate 14 is provided with a positive electrode column 141 in the direction along the axis of the battery cell assembly 1. The positive electrode cover plate 16 is provided with a first through hole in the direction along the axis of the battery cell assembly 1. The positive electrode column 141 passes through the first through hole and is connected to the first fixing member 19;

[0048] The battery also includes a second fixing member 20, the negative current collecting plate 15 is provided with a negative electrode column 151 along the axis of the battery cell assembly 1, the negative electrode cover plate 17 is provided with a second through hole along the axis of the battery cell assembly 1, and the negative electrode column 151 passes through the second through hole and is connected to the second fixing member 20.

[0049] The present application arranges the positive electrode tab group 12 and the negative electrode tab group 13 at both ends of the battery cell body, which effectively reduces the space requirement of the tabs inside the battery cell, thereby improving the energy density of the battery, helping to ensure the uniformity of current distribution during the charging and discharging process of the battery, and avoiding the occurrence of battery short circuit. On this basis, the present application arranges the positive electrode tab group 12 and / or the negative electrode tab group 13 into a symmetrical fan-shaped structure. Compared with the traditional straight line or circular structure, the fan-shaped structure can increase the surface area in the same space. When the tabs are arranged in a fan shape, the tip can fit more compactly on the current collector, and the base is expanded to increase the contact area with the current collector. This arrangement can effectively reduce the contact resistance. And it also improves the battery's overcurrent capacity and current transmission efficiency, and is also beneficial to the dispersion of heat, further improving the safety and life of the battery, and can also further improve the battery's mass energy density. Compared with the prior art in which the pole ear group is a plurality of groups of symmetrical fan-shaped structures, the pole ear group of the present application is only one group of symmetrical fan-shaped structures, and the preparation process is simple and the cost is lower, the reproducibility is better, and the quality of the formed battery cell assembly is lower, which further improves the battery's mass energy density. A positive electrode collector plate 14 and a negative electrode collector plate 15 are respectively provided on the exposed surface of the positive pole ear group 12 and the exposed surface of the negative pole ear group 13, which can effectively collect the current in the battery cell assembly 1 and transmit it to the external circuit, reducing The internal resistance is reduced, and the current collection efficiency is improved. The positive cover plate 16 is further covered on the positive current collecting disk 14, and the negative cover plate 17 is covered on the negative current collecting disk 15, wherein the cover plate can provide additional mechanical support, enhance the overall structural stability of the current collecting disk, and at the same time simplify the assembly steps, thereby improving the production efficiency and consistency of the battery. On the basis of the above, by setting the material of the positive cover plate 16 and / or the negative cover plate 17 to plastic, not only the weight of the structural parts in the cylindrical battery is reduced, the mass energy density of the battery is greatly improved, the application field of the cylindrical battery is broadened, especially in the field of new energy vehicles, but also the preparation cost of the battery is significantly reduced. The present application further sets the first A fixing member 19 and a positive electrode column 141, a second fixing member 20 and a negative electrode column 151, so that the positive electrode column 141 can pass through the first through hole of the positive electrode current disk 14 and then be connected to the first fixing member 19, and the negative electrode column 151 can pass through the second through hole of the negative electrode current disk 15 and then be connected to the second fixing member 20, thereby enhancing the mechanical strength of the battery, reducing loosening or damage of the connection caused by vibration or impact during use, and improving the stability and safety of the battery. The sizes of the first fixing member 19 and the second fixing member 20 of the present application can be matched according to the overcurrent requirements of the battery, and the manufacturer can match the sizes of different fixings according to the different rates and currents of the battery, and the assembly is more convenient and efficient.In some embodiments, both the positive electrode tab group 12 and the negative electrode tab group 13 have a symmetrical fan-shaped structure, and a preset angle is provided between the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, and the range of the preset angle is 30°-90°. A preset angle is provided between the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, which can increase the infiltration efficiency of the electrolyte, and further limit the range of the preset angle to 30°-90°, thereby ensuring the overcurrent capacity of the electrode group, while avoiding the problem of poor electrolyte infiltration rate caused by a small preset angle. In some embodiments, such as. Figure 4 and Figure 5 As shown, the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 is orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13. Orthogonal here means that the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13 are perpendicular to each other. By limiting the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 to be orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, the overcurrent capacity of the battery is guaranteed and the electrolyte infiltration efficiency is increased. Compared with the annular tab group of the traditional cylindrical battery, this is mainly because the positive electrode tab group 12 and the negative electrode tab group 13 have a first vacant area and a second vacant area respectively. When the electrolyte infiltrates from the end face of the positive terminal, the positive electrode tab group 12 has a greater resistance to the electrolyte infiltration than the first vacant area. Similarly, the negative electrode tab group at the negative terminal has a greater resistance to the electrolyte infiltration. When the electrolyte infiltrates from both ends of the positive and negative electrodes at the same time, due to the symmetrical fan-shaped structure of the positive electrode tab group and the symmetrical fan-shaped structure of the negative electrode tab group, the center line of the symmetrical fan-shaped structure of the positive electrode tab group is perpendicular to the negative electrode tab group. The center lines of the symmetrical fan-shaped structure of the pole lug group 13 are orthogonal, and the electrolyte can quickly flow from the first vacant area to the negative terminal end face, and quickly flow from the second vacant area to the negative terminal end face, avoiding the problem of poor electrolyte infiltration rate due to the small preset angle range between the center lines of the two. This is mainly because if the preset angle range is small, the electrolyte flowing from the first vacant area and the electrolyte flowing from the second vacant area overlap, which leads to strong resistance and a significant decrease in the infiltration rate. Therefore, the electrolyte can be staggered and infiltrated from both ends of the battery cell assembly 1, shortening the injection time. At the same time, it will be able to further reduce the total weight of the battery and further improve the battery's mass energy density.

[0050] Specifically, Figure 4 and Figure 5As shown, the positive electrode tab group 12 includes a fan-shaped first positive electrode tab group 121 and a fan-shaped second positive electrode tab group 122, and the negative electrode tab group 13 includes a fan-shaped first negative electrode tab group 131 and a fan-shaped second negative electrode tab group 132. The first positive electrode tab group 121 and the second positive electrode tab group 122 are symmetrically arranged along the radial direction of the battery body 11, and the first negative electrode tab group 131 and the second negative electrode tab group 132 are symmetrically arranged along the radial direction of the battery body 11. The symmetrical fan-shaped design can provide better mechanical stability, help maintain the integrity of the tabs during battery assembly and use, and can also package the battery unit more compactly, achieving higher energy density in a limited space. The first positive electrode tab group 121, the second positive electrode tab group 122, the first negative electrode tab group 131 and the second negative electrode tab group 132 are arranged in a fan-shaped structure, which reduces resistance and improves current transmission efficiency.

[0051] Specifically, the battery cell assembly 1 is formed by stacking and winding a positive electrode sheet, a negative electrode sheet and a separator to form a cylinder, the end faces of the positive terminal and the negative terminal are both circular end faces, a plurality of positive electrode ears are arranged at intervals on the positive electrode sheet, and a plurality of negative electrode ears are arranged at intervals on the negative electrode sheet. The plurality of positive electrode ears form a fan-shaped first positive electrode ear group 121 and a second positive electrode ear group 122 on the end face of the positive terminal of the battery cell assembly 1, and the plurality of negative electrode ears form a first negative electrode ear group 131 and a second negative electrode ear group 132 on the end face of the negative terminal of the battery cell assembly 1. When the positive electrode sheet and the negative electrode sheet are unfolded, a plurality of positive electrode ears at different intervals are arranged on the positive electrode sheet, and a plurality of negative electrode ears at different intervals are arranged on the negative electrode sheet. When the positive electrode sheet and the negative electrode sheet are wound, the plurality of positive electrode ears on the positive electrode sheet form a plurality of arc-shaped positive electrode ears on the end face of the positive terminal, thereby forming a fan-shaped first positive electrode ear group 121 and a second positive electrode ear group 122, and the plurality of negative electrode ears on the negative electrode sheet form a plurality of arc-shaped negative electrode ears on the end face of the negative terminal, thereby forming a fan-shaped first negative electrode ear group 131 and a second negative electrode ear group 132. The battery cell assembly 1 is formed by winding, which can make the electrode material more compact, reduce the gap inside the battery cell, thereby improving the energy density of the battery, and at the same time make the battery production efficiency higher and can be mass-produced.

[0052] Specifically, the positive electrode sheet is coated with a sodium ion positive electrode material, and the diaphragm is a glue-coated diaphragm.

[0053] In some embodiments, the first positive electrode tab group 121 includes a plurality of arc-shaped positive electrode tabs, the plurality of positive electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the sector, and the first negative electrode tab group 131 includes a plurality of negative electrode tabs, the plurality of negative electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the sector. By limiting the arc lengths of the plurality of positive electrode tabs to change progressively along the radial direction of the sector and the arc lengths of the plurality of negative electrode tabs to change progressively along the radial direction of the sector, the resistance of the battery is effectively reduced and the overcurrent capacity of the battery is improved.

[0054] Specifically, the first positive electrode tab group 121 includes a plurality of arc-shaped positive tabs, which are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of positive tabs gradually increase along the radial direction of the sector, and the first negative electrode tab group 131 includes a plurality of negative tabs, which are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of negative tabs gradually increase along the radial direction of the sector. By setting the arc lengths of the plurality of positive tabs to gradually increase, and the arc lengths of the plurality of negative tabs to gradually increase, the contact area of ​​the tabs can be increased, and the overcurrent capacity of the battery can be improved.

[0055] In some embodiments, the second positive electrode tab group 122 includes a plurality of arc-shaped positive electrode tabs, which are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the fan-shaped structure; the second negative electrode tab group 132 includes a plurality of negative electrode tabs, which are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the fan-shaped structure. By limiting the arc lengths of the plurality of positive electrode tabs to change progressively along the radial direction of the fan-shaped structure and the arc lengths of the plurality of negative electrode tabs to change progressively along the radial direction of the fan-shaped structure, the resistance of the battery is effectively reduced and the overcurrent capacity of the battery is improved.

[0056] Specifically, the first positive electrode tab group 121 includes a plurality of arc-shaped positive tabs, which are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of positive tabs gradually increase along the radial direction of the sector, and the first negative electrode tab group 131 includes a plurality of negative tabs, which are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of negative tabs gradually increase along the radial direction of the sector. By setting the arc lengths of the plurality of positive tabs to gradually increase, and the arc lengths of the plurality of negative tabs to gradually increase, the contact area of ​​the tabs can be increased, and the overcurrent capacity of the battery can be improved.

[0057] In some embodiments, the arc length of the positive electrode ear is set to satisfy the following formula: (2×π×r1) / x1≤W1≤(2×π×r1) / y1, wherein W1 is the arc length of the positive electrode ear, r1 is the arc radius of the positive electrode ear, x1 is in the range of 2 to 8, y1 is in the range of 2 to 8, y1<x1

[0058] Specifically, the value of x1 is 8 and the value of y1 is 3.

[0059] In some embodiments, the arc length setting of the negative electrode ear satisfies the following formula: (2×π×r2) / x2≤W2≤(2×π×r2) / y2, wherein W2 is the arc length of the negative electrode ear, r2 is the arc radius of the negative electrode ear, the value range of x2 is 2 to 8, the value range of y2 is 2 to 8, and y2<x2.

[0060] Specifically, the value of x2 is 8 and the value of y2 is 3.

[0061] By limiting the above formula, the arc length of the positive and negative ears can be accurately controlled, the internal resistance of the battery can be reduced, and the battery's charge and discharge efficiency can be improved. At the same time, a larger active material loading can be achieved at the same volume or weight, thereby improving the battery's energy density.

[0062] In some embodiments, such as Fig. 9 and Fig.10 As shown, the positive electrode cover plate 16 is provided with a first thickened area 161 and a first concave area 162, the first thickened area 161 protrudes from the inner surface of the positive electrode cover plate 16, the first concave area 162 is recessed in the inner surface of the positive electrode cover plate 16, and the positive current collecting plate 14 is embedded in the first concave area 162; the positive electrode tab group 12 protrudes from the surface of the battery cell body 11, and a first vacant area is formed between the first positive electrode tab group 121 and the second positive electrode tab group 122, and the first thickened area 161 is embedded in the first vacant area.

[0063] Specifically, Figure 4 As shown, the first vacant area is a symmetrical fan-shaped structure. The first vacant area here is an area on the end surface of the positive terminal that does not contain a positive electrode ear.

[0064] Specifically, Fig.10 As shown, the first concave area 162 and the first thickened area 161 both have a symmetrical fan-shaped structure. Specifically, the first concave area 162 includes a fan-shaped first positive electrode concave area and a fan-shaped second positive electrode concave area, and the first positive electrode concave area and the second positive electrode concave area are symmetrically arranged along the radial direction of the battery cell body 11, and the first thickened area 161 includes a fan-shaped first positive electrode thickened area and a fan-shaped second positive electrode thickened area, and the first positive electrode thickened area and the second positive electrode thickened area are symmetrically arranged along the radial direction of the battery cell body 11.

[0065] In some embodiments, the inner surface of the first concave area 162 abuts against the surface of the positive current collecting disk 14 close to the positive electrode cover plate 16 , and the inner surface of the first thickened area 161 abuts against the surface of the first vacant area.

[0066] In some embodiments, the depression depth of the first concave area 162 is greater than or equal to the protrusion height of the positive electrode tab group 12 from the surface of the battery body 11. Such a configuration can improve the space utilization rate inside the battery without increasing the total volume of the battery, further improving the volume energy density of the battery.

[0067] Preferably, the depression depth of the first concave area 162 is equal to the protrusion height of the positive electrode tab group 12 protruding from the surface of the battery cell body 11. Such a configuration can greatly improve the volume energy density of the battery.

[0068] In some embodiments, the protrusion height of the first thickened area 161 protruding from the inner surface of the positive electrode cover plate 16 is greater than or equal to the protrusion height of the positive electrode tab group 12 protruding from the surface of the battery cell body 11. Preferably, the protrusion height of the first thickened area 161 protruding from the inner surface of the positive electrode cover plate 16 is greater than the protrusion height of the positive electrode tab group 12 protruding from the surface of the battery cell body 11. Such a configuration can further improve the torsional strength of the positive electrode cover plate 16 and improve the stability of the battery.

[0069] In some embodiments, an explosion-proof valve is provided on the positive electrode cover plate 16, and the explosion-proof valve is recessed in the inner surface of the first thickened area 161. By providing the explosion-proof valve on the positive electrode cover plate 16, the battery can be prevented from exploding or rupturing under abnormal circumstances, thereby improving the safety performance of the battery.

[0070] Specifically, the number of explosion-proof valves is 1. Such an arrangement can improve the production efficiency of the battery.

[0071] In some embodiments, the negative electrode cover plate 17 is provided with a second thickened area 171 and a second concave area 172, the second thickened area 171 protrudes from the inner surface of the negative electrode cover plate 17, the second concave area 172 is recessed in the inner surface of the negative electrode cover plate 17, and the negative electrode collector plate 15 is embedded in the second concave area 172; the negative electrode tab group 13 protrudes from the surface of the battery cell body 11, a second vacant area is formed between the first negative electrode tab group 131 and the second negative electrode tab group 132, and the second thickened area 171 is embedded in the second vacant area. The second vacant area here refers to the area on the end surface of the negative terminal that does not contain a negative electrode tab.

[0072] Specifically, the second concave area 172 and the second thickened area 171 both have a symmetrical fan-shaped structure.

[0073] Specifically, the second concave area 172 includes a fan-shaped first negative electrode concave area and a fan-shaped second negative electrode concave area, and the first negative electrode concave area and the second negative electrode concave area are symmetrically arranged along the radial direction of the battery cell body 11. The second thickened area 171 includes a fan-shaped first negative electrode thickened area and a fan-shaped second negative electrode thickened area, and the first negative electrode thickened area and the second negative electrode thickened area are symmetrically arranged along the radial direction of the battery cell body 11.

[0074] Specifically, the second vacant area has a symmetrical fan-shaped structure.

[0075] In some embodiments, the inner surface of the second concave area 172 abuts against the surface of the negative electrode current collecting disk 15 close to the positive electrode cover plate 17 , and the inner surface of the second thickened area 171 abuts against the surface of the second vacant area.

[0076] In some embodiments, the depression depth of the second concave area 172 is greater than or equal to the protrusion height of the negative electrode tab group 13 protruding from the surface of the battery body 11. Through the above arrangement, the space utilization inside the battery can be improved without increasing the total volume of the battery, and the volume energy density of the battery is further improved. Preferably, the depression depth of the second concave area 172 is equal to the protrusion height of the negative electrode tab group 13 protruding from the surface of the battery body 11. Such an arrangement can greatly improve the volume energy density of the battery.

[0077] In some embodiments, the protrusion height of the second thickened area 171 from the inner surface of the negative electrode cover plate 17 is greater than the protrusion height of the negative electrode tab group 13 from the surface of the battery cell body 11. This arrangement can further improve the torsional strength of the negative electrode cover plate 17 and improve the stability of the battery.

[0078] In some embodiments, the center lines of the symmetrical fan-shaped structure of the first concave area 162 and the symmetrical fan-shaped structure of the second concave area 172 are orthogonal. Orthogonal here means that the center lines of the symmetrical fan-shaped structure of the first concave area 162 and the symmetrical fan-shaped structure of the second concave area 172 are perpendicular to each other.

[0079] In some embodiments, the center lines of the symmetrical fan-shaped structure of the first thickened area 161 and the symmetrical fan-shaped structure of the second thickened area 171 are orthogonal. Orthogonal here means that the center lines of the symmetrical fan-shaped structure of the first thickened area 161 and the symmetrical fan-shaped structure of the second thickened area 171 are perpendicular to each other.

[0080] By setting a first thickened area 161 on the positive cover plate 16 and a second thickened area 171 on the negative cover plate 17, the torsional strength of the cover plate is greatly improved. At the same time, the first thickened area 161 is embedded in the first vacant area, and the second thickened area 171 is embedded in the second vacant area, which avoids the occurrence of string movement of the battery cell assembly 1 and improves the stability of the battery; in addition, a first concave area 162 is set on the positive cover plate 16, and a second concave area 172 is set on the negative cover plate 17, wherein the positive current collecting plate 14 is embedded in the first concave area 162, and the negative current collecting plate 15 is embedded in the second concave area 172, which can effectively improve the volume energy density of the battery.

[0081] In some embodiments, the material of the positive electrode cover plate 16 is at least one of ABS, PP, PE, PVC, PC, and PS.

[0082] Specifically, the positive electrode cover plate 16 is prepared by an injection molding process.

[0083] In some embodiments, the negative electrode cover plate 17 is made of at least one of ABS, PP, PE, PVC, PC, and PS.

[0084] Specifically, the negative electrode cover plate 17 is prepared by an injection molding process.

[0085] The use of injection molding technology to prepare the positive electrode cover plate 16 and the negative electrode cover plate 17 can further reduce the cost of the battery, improve the production efficiency of the battery, and also shorten the development cycle of new cylindrical batteries.

[0086] In some embodiments, the positive electrode current collecting disc 14 and / or the negative electrode current collecting disc 15 has a symmetrical fan-shaped structure.

[0087] In some embodiments, the positive current collector 14 and the negative current collector 15 both have a symmetrical fan-shaped structure, and the center lines of the symmetrical fan-shaped structures of the positive current collector 14 and the negative current collector 15 are orthogonal. The positive current collector 14 and the negative current collector 15 are both set to a symmetrical fan-shaped structure, and the center lines of the symmetrical fan-shaped structures of the positive current collector 14 and the negative current collector 15 are orthogonal, so that they can better match the shape of the tab group and ensure the stability of the battery.

[0088] Specifically, the positive current collector 14 includes a first fan-shaped connection area and a second fan-shaped connection area, which are symmetrically arranged along the radial direction of the battery cell body 11, and the negative current collector 15 includes a third fan-shaped connection area and a fourth fan-shaped connection area, which are symmetrically arranged along the radial direction of the battery cell body 11.

[0089] In some embodiments, the positive electrode current collector 14 is provided with first strip-shaped welding areas arranged along the radial direction of the fan-shaped structure, and the negative electrode current collector 15 is provided with second strip-shaped welding areas arranged along the radial direction of the fan-shaped structure, the first strip-shaped welding areas are welded to the exposed surface of the positive electrode tab group 12, and the second strip-shaped welding areas are welded to the exposed surface of the negative electrode tab group 13. Preferably, the number of the first strip-shaped welding areas is 4, and the number of the second strip-shaped welding areas is 4.

[0090] Specifically, the first fan-shaped connection area is connected to the exposed surface of the first positive electrode tab group 121, the second fan-shaped connection area is connected to the exposed surface of the second positive electrode tab group 122, the third fan-shaped connection area is connected to the exposed surface of the first negative electrode tab group 131, and the fourth fan-shaped connection area is connected to the exposed surface of the second negative electrode tab group 132. Preferably, two first strip-shaped welding areas are provided in the first fan-shaped connection area, two first strip-shaped welding areas are provided in the second fan-shaped connection area, two second strip-shaped welding areas are provided in the third fan-shaped connection area, and two second strip-shaped welding areas are provided in the fourth fan-shaped connection area.

[0091] In some embodiments, the positive electrode current collecting disc 14 and the negative electrode current collecting disc 15 may be made of aluminum or copper. Preferably, the positive electrode current collecting disc 14 is made of aluminum, and the negative electrode current collecting disc 15 is made of copper.

[0092] In some embodiments, the battery further includes a shell 18, which is wrapped around the outer surface of the battery cell assembly 1, and the material of the shell 18 is an aluminum-plastic film. By limiting the material of the shell 18 to an aluminum-plastic film, the total weight of the battery can be further reduced and the mass energy density of the battery can be improved.

[0093] In some embodiments, the edge of the shell 18 near the positive electrode cover 16 is flush with the outer edge of the positive electrode cover 16, and the edge of the shell 18 near the negative electrode cover 17 is flush with the outer edge of the negative electrode cover 17. The use of aluminum-plastic film packaging solves the problem of single model specifications of cylindrical batteries on the market, further reduces the development cycle of cylindrical batteries, and the use of aluminum-plastic film shell 18 does not require pitting operations, further saving the investment cost of production line equipment and reducing development costs. In addition, the battery of the present application can be used for pack battery packs. Since the pack battery pack has a shell 18 on the outside, the battery can have certain safety performance even if it does not use an aluminum shell 18.

[0094] Specifically, a first sealant layer is provided on the outer edge of the positive electrode cover plate 16, an edge of the housing 18 close to the positive electrode cover plate 16 is bonded to the outer edge of the positive electrode cover plate 16 through the first sealant layer, a second sealant layer is provided on the outer edge of the negative electrode cover plate 17, and an edge of the housing 18 close to the negative electrode cover plate 17 is bonded to the outer edge of the negative electrode cover plate 17 through the second sealant layer. Adhesion using sealant layers helps to improve the service life and stability of the battery.

[0095] In some embodiments, a center line of the housing 18 along the length direction of the battery cell assembly 1 coincides with an axis of the battery cell assembly 1 .

[0096] In some embodiments, the outer surface of the positive electrode column 141 has an external thread, the first fixing member 19 is provided with an internal thread matching the positive electrode column 141 , and the first fixing member 19 is threadedly connected to the positive electrode column 141 .

[0097] Specifically, the first through hole is located at the center of the positive electrode cover plate 16 .

[0098] Specifically, the material of the positive electrode column 141 may be aluminum or copper. Preferably, the material of the positive electrode column 141 is aluminum.

[0099] In some embodiments, the negative electrode column 151 may be made of aluminum or copper.

[0100] In some embodiments, the outer surface of the negative electrode column 151 has an external thread, the second fixing member 20 is provided with an internal thread matching the negative electrode column 151 , and the second fixing member 20 is threadedly connected to the negative electrode column 151 .

[0101] Specifically, the second through hole is located at the center of the negative electrode cover plate 17 .

[0102] In some embodiments, the battery further includes a first sealing ring and a second sealing ring, wherein the first sealing ring is sleeved on the positive electrode column 141 and is located between the first fixing member 19 and the positive electrode current collecting disk 14, and the second sealing ring is sleeved on the negative electrode column 151 and is located between the second fixing member 20 and the negative electrode current collecting disk 15. By providing the sealing ring, the positive electrode of the battery and the electrolyte can be effectively isolated to prevent leakage of the electrolyte, thereby avoiding damage to the battery and energy reduction.

[0103] Specifically, one side surface of the first sealing ring is in contact with the outer surface of the positive electrode current collecting disk 14 , and the other side surface is in contact with the surface of the positive electrode column 141 close to the positive electrode current collecting disk 14 .

[0104] Specifically, one side surface of the second sealing ring is in contact with the outer surface of the negative electrode current collecting disk 15 , and the other side surface is in contact with the surface of the negative electrode column 151 close to the negative electrode current collecting disk 15 .

[0105] Specifically, the material of the first sealing ring and the second sealing ring can be at least one of nitrile rubber, natural rubber, silicone rubber, ethylene propylene rubber and fluororubber. Preferably, the material of the first sealing ring and the second sealing ring is fluororubber.

[0106] This embodiment also provides a method for preparing a soft-package cylindrical sodium-ion battery, which is used to prepare the soft-package cylindrical sodium-ion battery described in the above embodiment, and the preparation method comprises:

[0107] S1: Provide a battery cell assembly 1, a positive electrode current collector 14, a negative electrode current collector 15, a positive electrode cover 16 and a negative electrode cover 17; wherein the battery cell assembly 1 includes a battery cell body 11, a positive electrode tab group 12, a negative electrode tab group 13, a first fixing member 19, a second fixing member 20, a positive electrode column 141 and a negative electrode column 151, the positive electrode tab group 12 is arranged on the positive end of the battery cell body 11, the negative electrode tab group 13 is arranged on the negative end of the battery cell body 11, and the positive electrode tab group 12 and / or the negative electrode tab group 13 have a symmetrical fan-shaped structure;

[0108] In some embodiments, both the positive electrode tab group 12 and the negative electrode tab group 13 have a symmetrical fan-shaped structure, and there is a preset angle between the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, and the range of the preset angle is 30°-90°. There is a preset angle between the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, which can increase the infiltration efficiency of the electrolyte, and further limit the range of the preset angle to 30°-90°, ensuring the overcurrent capacity of the electrode group, while avoiding the problem of poor infiltration rate of the electrolyte due to the small angle of the preset angle. In some embodiments, the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 is orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13. Orthogonal here means that the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 and the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13 are perpendicular to each other. By limiting the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 to be orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, the infiltration efficiency of the electrolyte is increased. Compared with the annular tab group of the traditional cylindrical battery, the positive electrode tab group 12 and the negative electrode tab group 13 have a first vacant area and a second vacant area, respectively, so that the electrolyte can be staggered and infiltrated from both ends of the battery cell assembly 1, shortening the injection time, while also being able to further reduce the total weight of the battery and further improve the mass energy density of the battery. By limiting the center line of the symmetrical fan-shaped structure of the positive electrode tab group 12 to be orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group 13, the overcurrent capacity of the battery is guaranteed and the electrolyte infiltration efficiency is increased. Compared with the annular tab group of the traditional cylindrical battery, this is mainly because the positive electrode tab group 12 and the negative electrode tab group 13 have a first vacant area and a second vacant area respectively. When the electrolyte infiltrates from the end face of the positive terminal, the positive electrode tab group 12 has a greater resistance to the electrolyte infiltration than the first vacant area. Similarly, the negative electrode tab group at the negative terminal has a greater resistance to the electrolyte infiltration. When the electrolyte infiltrates from both ends of the positive and negative electrodes at the same time, due to the symmetrical fan-shaped structure of the positive electrode tab group and the symmetrical fan-shaped structure of the negative electrode tab group, the center line of the symmetrical fan-shaped structure of the positive electrode tab group is perpendicular to the negative electrode tab group. The center lines of the symmetrical fan-shaped structure of the pole lug group 13 are orthogonal, and the electrolyte can quickly flow from the first vacant area to the negative terminal end face, and quickly flow from the second vacant area to the negative terminal end face, avoiding the problem of poor electrolyte infiltration rate due to the small preset angle range between the center lines of the two. This is mainly because if the preset angle range is small, the electrolyte flowing from the first vacant area and the electrolyte flowing from the second vacant area overlap, which leads to strong resistance and a significant decrease in the infiltration rate. Therefore, the electrolyte can be staggered and infiltrated from both ends of the battery cell assembly 1, shortening the injection time. At the same time, it will be able to further reduce the total weight of the battery and further improve the battery's mass energy density.

[0109] Specifically, the positive electrode tab group 12 includes a fan-shaped first positive electrode tab group 121 and a fan-shaped second positive electrode tab group 122, and the negative electrode tab group 13 includes a fan-shaped first negative electrode tab group 131 and a fan-shaped second negative electrode tab group 132. The first positive electrode tab group 121 and the second positive electrode tab group 122 are symmetrically arranged along the radial direction of the battery body 11, and the first negative electrode tab group 131 and the second negative electrode tab group 132 are symmetrically arranged along the radial direction of the battery body 11. The symmetrical fan-shaped design can provide better mechanical stability, help maintain the integrity of the tabs during battery assembly and use, and can also package the battery unit more compactly, achieving higher energy density in a limited space. The first positive electrode tab group 121, the second positive electrode tab group 122, the first negative electrode tab group 131 and the second negative electrode tab group 132 are arranged in a fan-shaped structure, which reduces resistance and improves current transmission efficiency.

[0110] In some embodiments, providing the battery cell assembly 1 includes: providing a positive electrode sheet, a negative electrode sheet, and a separator, and stacking and winding the positive electrode sheet, the negative electrode sheet, and the separator to form the battery cell assembly 1.

[0111] The positive electrode sheet, the negative electrode sheet and the separator are stacked and wound to form a battery cell assembly 1, which includes: a plurality of positive electrode ears are provided on the positive electrode sheet, and a plurality of negative electrode ears are provided on the negative electrode sheet. The positive electrode sheet, the negative electrode sheet and the separator are wound so that the plurality of positive electrode ears form a fan-shaped first positive electrode ear group 121 and a second positive electrode ear group 122 on the end face of the positive terminal of the battery cell assembly 1, and the plurality of negative electrode ears form a fan-shaped first negative electrode ear group 131 and a second negative electrode ear group 132 on the end face of the negative terminal of the battery cell assembly 1. When the positive and negative electrodes are unfolded, multiple positive and negative electrodes are provided with different intervals. When the positive and negative electrodes are wound, the multiple positive electrodes on the positive electrodes form multiple arc-shaped positive electrodes on the end face of the positive electrode terminal, thereby forming a fan-shaped first positive electrode electrode group 121 and a second positive electrode electrode group 122, while the multiple negative electrodes on the negative electrodes form multiple arc-shaped negative electrodes on the end face of the negative electrode terminal, thereby forming a fan-shaped first negative electrode electrode group 131 and a second negative electrode electrode group 132. The battery cell assembly 1 is formed by winding, which can make the electrode material more compact, reduce the gap inside the battery cell, thereby improving the energy density of the battery, and at the same time make the battery production efficiency higher and can be mass-produced.

[0112] Specifically, the positive electrode sheet is coated with a sodium ion positive electrode material, and the diaphragm is a glue-coated diaphragm.

[0113] In some embodiments, the first positive electrode tab group 121 includes a plurality of arc-shaped positive electrode tabs, the plurality of positive electrode tabs are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the fan-shaped structure; the first negative electrode tab group 131 includes a plurality of negative electrode tabs, the plurality of negative electrode tabs are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the fan-shaped structure. By limiting the arc lengths of the plurality of positive electrode tabs to change progressively along the radial direction of the fan-shaped structure and the arc lengths of the plurality of negative electrode tabs to change progressively along the radial direction of the fan-shaped structure, the resistance of the battery is effectively reduced and the overcurrent capacity of the battery is improved.

[0114] Specifically, the positive electrode sheet is coated with a sodium ion positive electrode material, and the diaphragm is a glue-coated diaphragm.

[0115] In some embodiments, the second positive electrode tab group 122 includes a plurality of arc-shaped positive electrode tabs, which are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the fan-shaped structure; the second negative electrode tab group 132 includes a plurality of negative electrode tabs, which are arranged at intervals along the radial direction of the fan-shaped structure, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the fan-shaped structure. By limiting the arc lengths of the plurality of positive electrode tabs to change progressively along the radial direction of the fan-shaped structure and the arc lengths of the plurality of negative electrode tabs to change progressively along the radial direction of the fan-shaped structure, the resistance of the battery is effectively reduced and the overcurrent capacity of the battery is improved.

[0116] In some embodiments, the arc length setting of the positive electrode ear satisfies the following formula: (2×π×r1) / x1≤W1≤(2×π×r1) / y1, wherein W1 is the arc length of the positive electrode ear, r1 is the arc radius of the positive electrode ear, the value range of x1 is 2 to 8, the value range of y1 is 2 to 8, and y1<x1.

[0117] Specifically, the value of x1 is 8 and the value of y1 is 3.

[0118] In some embodiments, the arc length setting of the negative electrode ear satisfies the following formula: (2×π×r2) / x2≤W2≤(2×π×r2) / y2, wherein W2 is the arc length of the negative electrode ear, r2 is the arc radius of the negative electrode ear, the value range of x2 is 2 to 8, the value range of y2 is 2 to 8, and y2<x2.

[0119] Specifically, the value of x2 is 8 and the value of y2 is 3.

[0120] By limiting the above formula, the arc length of the positive and negative ears can be accurately controlled, the internal resistance of the battery can be reduced, and the battery's charge and discharge efficiency can be improved. At the same time, a larger active material loading can be achieved at the same volume or weight, thereby improving the battery's energy density.

[0121] S2: Weld the positive current collector 14 to the exposed surface of the positive electrode tab group 12 so that the positive current collector 14 covers the exposed surface of the positive electrode tab group 12, and weld the negative current collector 15 to the exposed surface of the negative electrode tab group 13 so that the negative current collector 15 covers the exposed surface of the negative electrode tab group 13.

[0122] In some embodiments, the positive electrode current collector 14 is provided with first strip-shaped welding areas arranged along the radial direction of the fan-shaped structure, and the negative electrode current collector 15 is provided with second strip-shaped welding areas arranged along the radial direction of the fan-shaped structure. Preferably, the number of the first strip-shaped welding areas is 4, and the number of the second strip-shaped welding areas is 4.

[0123] In some embodiments, the positive current collecting disc 14 and the exposed surface of the positive electrode tab group 12 are welded, including: flattening the exposed surface of the positive electrode tab group 12 , and then welding the positive current collecting disc 14 and the exposed surface of the positive electrode tab group 12 through the first strip welding area on the positive current collecting disc 14 .

[0124] In some embodiments, the negative electrode current collector plate 15 is welded to the exposed surface of the negative electrode tab group 13 , including: flattening the exposed surface of the negative electrode tab group 13 , and then welding the negative electrode current collector plate 15 to the exposed surface of the negative electrode tab group 13 through the second strip welding area on the negative electrode current collector plate 15 .

[0125] In some embodiments, the positive electrode current collecting disc 14 and / or the negative electrode current collecting disc 15 has a symmetrical fan-shaped structure.

[0126] In some embodiments, the positive current collector 14 and the negative current collector 15 both have a symmetrical fan-shaped structure, and the center lines of the symmetrical fan-shaped structures of the positive current collector 14 and the negative current collector 15 are orthogonal. The positive current collector 14 and the negative current collector 15 are both set to a symmetrical fan-shaped structure, and the center lines of the symmetrical fan-shaped structures of the positive current collector 14 and the negative current collector 15 are orthogonal, so that they can better match the shape of the tab group and ensure the stability of the battery.

[0127] In some embodiments, the positive current collector 14 includes a first fan-shaped connection area and a second fan-shaped connection area, which are symmetrically arranged along the radial direction of the battery cell body 11, and the negative current collector 15 includes a third fan-shaped connection area and a fourth fan-shaped connection area, which are symmetrically arranged along the radial direction of the battery cell body 11.

[0128] Specifically, the first fan-shaped connection area is connected to the exposed surface of the first positive electrode tab group 121, the second fan-shaped connection area is connected to the exposed surface of the second positive electrode tab group 122, the third fan-shaped connection area is connected to the exposed surface of the first negative electrode tab group 131, and the fourth fan-shaped connection area is connected to the exposed surface of the second negative electrode tab group 132.

[0129] Preferably, two first strip-shaped welding areas are provided in the first fan-shaped connection area, two first strip-shaped welding areas are provided in the second fan-shaped connection area, two second strip-shaped welding areas are provided in the third fan-shaped connection area, and two second strip-shaped welding areas are provided in the fourth fan-shaped connection area.

[0130] In some embodiments, the positive electrode current collecting disc 14 and the negative electrode current collecting disc 15 may be made of aluminum or copper.

[0131] Specifically, the positive electrode current collecting disc 14 is made of aluminum, and the negative electrode current collecting disc 15 is made of copper.

[0132] S3: Connect the positive electrode cover plate 16 to the positive electrode current collecting disc 14 so that the positive electrode cover plate 16 is covered on the positive electrode current collecting disc 14, and connect the negative electrode cover plate 17 to the negative electrode current collecting disc 15 so that the negative electrode cover plate 17 is covered on the negative electrode current collecting disc 15 to obtain a first prefabricated battery cell, wherein the material of the positive electrode cover plate 16 and / or the negative electrode cover plate 17 is plastic. Setting the material of the positive electrode cover plate 16 and / or the negative electrode cover plate 17 to plastic can further improve the mass energy density of the battery.

[0133] In some embodiments, the positive electrode cover plate 16 is connected to the positive electrode current collecting disk 14 so that the positive electrode cover plate 16 is covered on the positive electrode current collecting disk 14, and the negative electrode cover plate 17 is connected to the negative electrode current collecting disk 15 so that the negative electrode cover plate 17 is covered on the negative electrode current collecting disk 15, and a first prefabricated battery cell is obtained, including: the positive electrode current collecting disk 14 is provided with a positive electrode column 141 in the direction along the axis of the battery cell assembly 1, and the positive electrode cover plate 16 is provided with a first through hole in the direction along the axis of the battery cell assembly 1, and the positive electrode column 141 is passed through the first through hole and then connected to the first fixing member 19, so that the positive electrode cover plate 16 is covered on the positive electrode current collecting disk 14;

[0134] The negative electrode collector plate 15 is provided with a negative electrode column 151 in the direction along the axis of the battery cell assembly 1, and the negative electrode cover plate 17 is provided with a second through hole in the direction along the axis of the battery cell assembly 1. The negative electrode column 151 is passed through the second through hole and connected to the second fixing member 20, so that the negative electrode cover plate 17 is covered on the negative electrode collector plate 15 to obtain a first prefabricated battery cell. Specifically, the first through hole is located at the center of the positive electrode cover plate 16, and the second through hole is located at the center of the negative electrode cover plate 17. Specifically, the material of the positive electrode column 141 can be aluminum or copper. Preferably, the material of the positive electrode column 141 is aluminum. Specifically, the material of the negative electrode column 151 can be aluminum or copper. The present application further provides a first fixing member 19 and a positive electrode column 141, a second fixing member 20 and a negative electrode column 151, so that the positive electrode column 141 can pass through the first through hole of the positive electrode current disk 14 and then be connected to the first fixing member 19, and the negative electrode column 151 can pass through the second through hole of the negative electrode current disk 15 and then be connected to the second fixing member 20, thereby enhancing the mechanical strength of the battery, reducing loosening or damage of the connection caused by vibration or impact during use, and improving the stability and safety of the battery. The sizes of the first fixing member 19 and the second fixing member 20 of the present application can be matched according to the overcurrent requirements of the battery, and the manufacturer can match the sizes of different fixings according to the different rates and currents of the battery, and the assembly is more convenient and efficient.

[0135] In some embodiments, the outer surface of the positive electrode column 141 has an external thread, the first fixing member 19 is provided with an internal thread matching the positive electrode column 141, and the first fixing member 19 is threadedly connected to the positive electrode column 141; the outer surface of the negative electrode column 151 has an external thread, the second fixing member 20 is provided with an internal thread matching the negative electrode column 151, and the second fixing member 20 is threadedly connected to the negative electrode column 151.

[0136] In some embodiments, the battery further includes a first sealing ring and a second sealing ring, wherein the first sealing ring is sleeved on the positive electrode column 141 and is located between the first fixing member 19 and the positive electrode current collecting disk 14, and the second sealing ring is sleeved on the negative electrode column 151 and is located between the second fixing member 20 and the negative electrode current collecting disk 15. By providing the sealing ring, the positive electrode of the battery and the electrolyte can be effectively isolated to prevent leakage of the electrolyte, thereby avoiding damage to the battery and energy reduction.

[0137] Specifically, one side surface of the first sealing ring is in contact with the outer surface of the positive electrode current collecting disk 14 , and the other side surface is in contact with the surface of the positive electrode column 141 close to the positive electrode current collecting disk 14 .

[0138] Specifically, one side surface of the second sealing ring is in contact with the outer surface of the negative electrode current collecting disk 15 , and the other side surface is in contact with the surface of the negative electrode column 151 close to the negative electrode current collecting disk 15 .

[0139] Specifically, the material of the first sealing ring and the second sealing ring can be at least one of nitrile rubber, natural rubber, silicone rubber, ethylene propylene rubber and fluororubber. Preferably, the material of the first sealing ring and the second sealing ring is fluororubber.

[0140] In some embodiments, such as Fig. 9 and Fig.10 As shown, the positive electrode cover plate 16 is provided with a first thickened area 161 and a first concave area 162, the first thickened area 161 protrudes from the inner surface of the positive electrode cover plate 16, the first concave area 162 is recessed in the inner surface of the positive electrode cover plate 16, and the positive electrode collector 14 is embedded in the first concave area 162; the positive electrode tab group 12 protrudes from the surface of the battery cell body 11, and a first vacant area is formed between the first positive electrode tab group 121 and the second positive electrode tab group 122, and the first thickened area 161 is embedded in the first vacant area. The first vacant area here is an area on the end face of the positive terminal that does not contain a positive tab.

[0141] Specifically, Fig.10 As shown, the first concave area 162 and the first thickened area 161 both have a symmetrical fan-shaped structure. Specifically, the first concave area 162 includes a fan-shaped first positive electrode concave area and a fan-shaped second positive electrode concave area, and the first positive electrode concave area and the second positive electrode concave area are symmetrically arranged along the radial direction of the battery cell body 11, and the first thickened area 161 includes a fan-shaped first positive electrode thickened area and a fan-shaped second positive electrode thickened area, and the first positive electrode thickened area and the second positive electrode thickened area are symmetrically arranged along the radial direction of the battery cell body 11.

[0142] In some embodiments, the inner surface of the first concave area 162 abuts against the surface of the positive current collecting disk 14 close to the positive electrode cover plate 16 , and the inner surface of the first thickened area 161 abuts against the surface of the first vacant area.

[0143] In some embodiments, the depression depth of the first concave area 162 is greater than or equal to the protrusion height of the positive electrode tab group 12 from the surface of the battery body 11. Such a configuration can improve the space utilization rate inside the battery without increasing the total volume of the battery, further improving the volume energy density of the battery.

[0144] Preferably, the depression depth of the first concave area 162 is equal to the protrusion height of the positive electrode tab group 12 protruding from the surface of the battery cell body 11. Such a configuration can greatly improve the volume energy density of the battery.

[0145] In some embodiments, the protrusion height of the first thickened area 161 from the inner surface of the positive electrode cover plate 16 is greater than or equal to the protrusion height of the positive electrode tab group 12 from the surface of the battery cell body 11. Preferably, the protrusion height of the first thickened area 161 from the inner surface of the positive electrode cover plate 16 is greater than the protrusion height of the positive electrode tab group 12 from the surface of the battery cell body 11. Such a configuration can further improve the torsional strength of the positive electrode cover plate and improve the stability of the battery.

[0146] In some embodiments, an explosion-proof valve is provided on the positive electrode cover plate 16, and the explosion-proof valve is recessed in the inner surface of the first thickened area 161. By providing the explosion-proof valve on the positive electrode cover plate 16, the battery can be prevented from exploding or rupturing under abnormal circumstances, thereby improving the safety performance of the battery.

[0147] Specifically, the number of explosion-proof valves is 1. Such an arrangement can improve the production efficiency of the battery.

[0148] In some embodiments, the negative electrode cover plate 17 is provided with a second thickened area 171 and a second concave area 172, the second thickened area 171 protrudes from the inner surface of the negative electrode cover plate 17, the second concave area 172 is recessed in the inner surface of the negative electrode cover plate 17, and the negative electrode collector plate 15 is embedded in the second concave area 172; the negative electrode tab group 13 protrudes from the surface of the battery cell body 11, a second vacant area is formed between the first negative electrode tab group 131 and the second negative electrode tab group 132, and the second thickened area 171 is embedded in the second vacant area. The second vacant area here refers to the area on the end surface of the negative terminal that does not contain a negative electrode tab.

[0149] Specifically, the second concave area 172 and the second thickened area 171 both have a symmetrical fan-shaped structure.

[0150] Specifically, the second concave area 172 includes a fan-shaped first negative electrode concave area and a fan-shaped second negative electrode concave area, and the first negative electrode concave area and the second negative electrode concave area are symmetrically arranged along the radial direction of the battery cell body 11. The second thickened area 171 includes a fan-shaped first negative electrode thickened area and a fan-shaped second negative electrode thickened area, and the first negative electrode thickened area and the second negative electrode thickened area are symmetrically arranged along the radial direction of the battery cell body 11.

[0151] Specifically, the second vacant area has a symmetrical fan-shaped structure.

[0152] In some embodiments, the inner surface of the second concave area 172 abuts against the surface of the negative electrode current collecting disk 15 close to the positive electrode cover plate 17 , and the inner surface of the second thickened area 171 abuts against the surface of the second vacant area.

[0153] In some embodiments, the depression depth of the second concave area 172 is greater than or equal to the protrusion height of the negative electrode tab group 13 protruding from the surface of the battery body 11. Through the above arrangement, the space utilization inside the battery can be improved without increasing the total volume of the battery, and the volume energy density of the battery is further improved. Preferably, the depression depth of the second concave area 172 is equal to the protrusion height of the negative electrode tab group 13 protruding from the surface of the battery body 11. Such an arrangement can greatly improve the volume energy density of the battery.

[0154] In some embodiments, the protrusion height of the second thickened area 171 from the inner surface of the negative electrode cover plate 17 is greater than the protrusion height of the negative electrode tab group 13 from the surface of the battery cell body 11. This arrangement can further improve the torsional strength of the negative electrode cover plate and improve the stability of the battery.

[0155] In some embodiments, the material of the positive electrode cover plate 16 is at least one of ABS, PP, PE, PVC, PC, and PS.

[0156] Specifically, the positive electrode cover plate 16 is prepared by an injection molding process.

[0157] In some embodiments, the center lines of the symmetrical fan-shaped structure of the first concave area 162 and the symmetrical fan-shaped structure of the second concave area 172 are orthogonal. Orthogonal here means that the center lines of the symmetrical fan-shaped structure of the first concave area 162 and the symmetrical fan-shaped structure of the second concave area 172 are perpendicular to each other.

[0158] In some embodiments, the center lines of the symmetrical fan-shaped structure of the first thickened area 161 and the symmetrical fan-shaped structure of the second thickened area 171 are orthogonal. Orthogonal here means that the center lines of the symmetrical fan-shaped structure of the first thickened area 161 and the symmetrical fan-shaped structure of the second thickened area 171 are perpendicular to each other.

[0159] By setting a first thickened area 161 on the positive electrode cover plate 16 and a second thickened area 171 on the negative electrode cover plate 17, the torsional strength of the cover plate is greatly improved. At the same time, the first thickened area 161 is embedded in the first vacant area, and the second thickened area 171 is embedded in the second vacant area, which avoids the occurrence of the string movement of the battery cell assembly 1 and improves the stability of the battery; in addition, a first concave area 162 is set on the positive electrode cover plate 16, and a second concave area 172 is set on the negative electrode cover plate 17, wherein the positive electrode collector plate 14 is embedded in the first concave area 162, and the negative electrode collector plate 15 is embedded in the second concave area 172, which can effectively improve the volume energy density of the battery. Through the above-mentioned settings, the space utilization rate inside the battery can be improved without increasing the total volume of the battery, and the volume energy density of the battery is further improved.

[0160] In some embodiments, the material of the positive electrode cover plate 16 is at least one of ABS, PP, PE, PVC, PC, and PS.

[0161] Specifically, the positive electrode cover plate 16 is prepared by an injection molding process.

[0162] The use of injection molding technology to prepare the positive electrode cover plate 16 and the negative electrode cover plate 17 can further reduce the cost of the battery, improve the production efficiency of the battery, and also shorten the development cycle of new cylindrical batteries.

[0163] In some embodiments, the negative electrode cover plate 17 is made of at least one of ABS, PP, PE, PVC, PC, and PS.

[0164] Specifically, the negative electrode cover plate 17 is prepared by an injection molding process.

[0165] S4: packaging the first prefabricated battery cell to obtain a soft-pack cylindrical sodium-ion battery.

[0166] In some embodiments, a first sealant layer is provided on the outer edge of the positive electrode cover plate 16 on the first prefabricated battery cell, and a second sealant layer is provided on the outer edge of the negative electrode cover plate 17 .

[0167] In some embodiments, the first prefabricated battery cell is packaged, including: providing a shell 18, the material of the shell 18 is an aluminum-plastic film; wrapping the shell 18 on the outer surface of the first prefabricated battery cell to obtain the wrapped first prefabricated battery cell, performing a hot pressing bonding process on the wrapped first prefabricated battery cell to obtain a second prefabricated battery cell, and performing a liquid injection formation process on the second prefabricated battery cell to obtain a soft-pack cylindrical sodium-ion battery. The use of aluminum-plastic film packaging solves the problem of the single model and specification of cylindrical batteries on the market, further reduces the development cycle of cylindrical batteries, and the use of aluminum-plastic film shell 18 does not require a flushing operation, further saving the investment cost of production line equipment and reducing development costs. In addition, the battery of the present application can be used for pack battery packs. Since the pack battery pack has a shell 18 on the outside, the battery can have certain safety performance even if it does not use an aluminum shell 18.

[0168] Specifically, the wrapped first prefabricated battery cell is subjected to a hot pressing bonding process, including: bonding the edge of the shell 18 close to the positive electrode cover plate 16 to the outer edge of the positive electrode cover plate 16 through a first sealing adhesive layer, bonding the edge of the shell 18 close to the negative electrode cover plate 17 to the outer edge of the negative electrode cover plate 17 through a second sealing adhesive layer to obtain the bonded first prefabricated battery cell, and hot pressing the bonded first prefabricated battery cell to obtain a second prefabricated battery cell, wherein the second prefabricated battery cell has an air bag. The use of a sealing adhesive layer for bonding helps to improve the service life and stability of the battery. At the same time, the positive electrode column 141 is connected to the first fixing member 19, and the negative electrode column 151 is connected to the second fixing member 20, which can enhance the mechanical strength of the battery, reduce the loosening or damage of the connection caused by vibration or impact during use, and improve the stability and safety of the battery.

[0169] In some embodiments, before performing the liquid injection and formation process on the second prefabricated battery cell, the process further includes: performing a drying process on the second prefabricated battery cell.

[0170] In some embodiments, the second prefabricated battery cell is subjected to liquid injection and formation treatment, including: injecting electrolyte from the air bag of the second prefabricated battery cell to obtain the second prefabricated battery cell after liquid injection, and discharging exhaust gas after the second prefabricated battery cell is subjected to formation treatment to obtain a soft-pack cylindrical sodium-ion battery.

[0171] In some embodiments, after the second prefabricated battery cell is subjected to the liquid injection and formation process, the second prefabricated battery cell is further subjected to the cutting process.

[0172] Specifically, the second prefabricated battery cell is subjected to a cutting process, including: cutting the air bag of the second prefabricated battery cell, performing hot-pressing sealing, and folding to obtain a soft-package cylindrical sodium-ion battery.

[0173] The above description shows and describes the preferred embodiment of the present invention. As mentioned above, it should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the invention concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not depart from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A soft-package cylindrical sodium ion battery, characterized in that: include: A battery cell assembly (1), comprising a battery cell body (11), a positive electrode tab group (12) and a negative electrode tab group (13), wherein the positive electrode tab group (12) is arranged on the positive terminal of the battery cell body (11), and the negative electrode tab group (13) is arranged on the negative terminal of the battery cell body (11), and the positive electrode tab group (12) and / or the negative electrode tab group (13) have a symmetrical fan-shaped structure; A positive electrode current collecting plate (14) is arranged to cover the exposed surface of the positive electrode tab group (12); A negative electrode current collecting plate (15) is arranged to cover the exposed surface of the negative electrode tab group (13); A positive electrode cover plate (16) is provided on the positive electrode current collecting plate (14); A negative electrode cover plate (17) is provided on the negative electrode current collecting plate (15); The material of the positive electrode cover plate (16) and / or the negative electrode cover plate (17) is plastic; The battery further comprises a first fixing member (19), the positive electrode current collecting plate (14) is provided with a positive electrode column (141) in a direction along the axis of the battery cell assembly (1), the positive electrode cover plate (16) is provided with a first through hole in a direction along the axis of the battery cell assembly (1), and the positive electrode column (141) is connected to the first fixing member (19) after passing through the first through hole; The battery further comprises a second fixing member (20), the negative electrode current collecting plate (15) is provided with a negative electrode column (151) in a direction along the axis of the battery cell assembly (1), the negative electrode cover plate (17) is provided with a second through hole in a direction along the axis of the battery cell assembly (1), and the negative electrode column (151) is connected to the second fixing member (20) after passing through the second through hole.

2. The battery according to claim 1, characterized in that The positive electrode tab group (12) and the negative electrode tab group (13) both have a symmetrical fan-shaped structure, and a preset angle is formed between the center line of the symmetrical fan-shaped structure of the positive electrode tab group (12) and the center line of the symmetrical fan-shaped structure of the negative electrode tab group (13), and the range of the preset angle is 30°-90°.

3. The battery according to claim 2, characterized in that The center line of the symmetrical fan-shaped structure of the positive electrode tab group (12) is orthogonal to the center line of the symmetrical fan-shaped structure of the negative electrode tab group (13).

4. The battery according to claim 1, characterized in that The battery further comprises a shell (18), the shell (18) being wrapped around the outer surface of the battery core assembly (1), and the shell (18) being made of an aluminum-plastic film.

5. The battery according to claim 4, characterized in that The edge of the shell (18) close to the positive electrode cover plate (16) is flush with the outer edge of the positive electrode cover plate (16), and the edge of the shell (18) close to the negative electrode cover plate (17) is flush with the outer edge of the negative electrode cover plate (17).

6. The battery according to claim 1, characterized in that The positive electrode tab group (12) comprises a first fan-shaped positive electrode tab group (121) and a second fan-shaped positive electrode tab group (122); the negative electrode tab group (13) comprises a first fan-shaped negative electrode tab group (131) and a second fan-shaped negative electrode tab group (132); the first positive electrode tab group (121) and the second positive electrode tab group (122) are symmetrically arranged along the radial direction of the battery cell body (11); and the first negative electrode tab group (131) and the second negative electrode tab group (132) are symmetrically arranged along the radial direction of the battery cell body (11).

7. The battery according to claim 6, characterized in that The first positive electrode tab group (121) comprises a plurality of arc-shaped positive electrode tabs, wherein the plurality of positive electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of positive electrode tabs change progressively along the radial direction of the sector; the first negative electrode tab group (131) comprises a plurality of negative electrode tabs, wherein the plurality of negative electrode tabs are arranged at intervals along the radial direction of the sector, and the arc lengths of the plurality of negative electrode tabs change progressively along the radial direction of the sector.

8. The battery according to claim 7, characterized in that The battery meets at least one of the following characteristics: The arc length setting of the positive electrode ear satisfies the following formula: (2×π×r1) / x1≤W1≤(2×π×r1) / y1, wherein W1 is the arc length of the positive electrode ear, r1 is the arc radius of the positive electrode ear, the value range of x1 is 2 to 8, the value range of y1 is 2 to 8, and y1<x1. The arc length setting of the negative electrode ear satisfies the following formula: (2×π×r2) / x2≤W2≤(2×π×r2) / y2, wherein W2 is the arc length of the negative electrode ear, r2 is the arc radius of the negative electrode ear, the value range of x2 is 2 to 8, the value range of y2 is 2 to 8, and y2<x2.

9. The battery according to claim 6, characterized in that The battery meets at least one of the following characteristics: The positive electrode cover plate (16) is provided with a first thickened area (161) and a first concave area (162), wherein the first thickened area (161) protrudes from the inner surface of the positive electrode cover plate (16), and the first concave area (162) is recessed into the inner surface of the positive electrode cover plate (16), and the positive electrode current collecting plate (14) is embedded in the first concave area (162); the positive electrode tab group (12) protrudes from the surface of the battery cell body (11), a first vacant area is formed between the first positive electrode tab group (121) and the second positive electrode tab group (122), and the first thickened area (161) is embedded in the first vacant area; The negative electrode cover plate (17) is provided with a second thickened area (171) and a second concave area (172); the second thickened area (171) protrudes from the inner surface of the negative electrode cover plate (17); the second concave area (172) is recessed into the inner surface of the negative electrode cover plate (17); the negative electrode current collecting plate (15) is embedded in the second concave area (172); the negative electrode tab group (13) protrudes from the surface of the battery cell body (11); a second vacant area is formed between the first negative electrode tab group (131) and the second negative electrode tab group (132); the second thickened area (171) is embedded in the second vacant area.

10. The battery according to claim 9, characterized in that The battery meets at least one of the following characteristics: The depression depth of the first concave area (162) is greater than or equal to the protrusion height of the positive electrode tab group (12) protruding from the surface of the battery cell body (11); The concave depth of the second concave area (172) is greater than or equal to the protruding height of the negative electrode tab group (13) protruding from the surface of the battery cell body (11).

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