Cylindrical battery cell, energy storage device and electric device

Abstract

The application relates to the technical field of batteries, in particular to a cylindrical battery cell, an energy storage device and an electric equipment. The cylindrical battery cell comprises two polar plates with opposite polarities and a diaphragm, the diaphragm is isolated between the two polar plates and is wound to form a cylindrical structure. The polar plate comprises a polar plate main body and a tab group, the tab group is arranged at one end of the polar plate main body along the width direction of the polar plate main body, the tab group comprises a first tab and a second tab arranged in sequence along a first direction, and the size W1 of the second tab along the length direction of the second tab satisfies W1 >= 2pi R, so that the second tab is wrapped around the outer periphery of the first tab when the cylindrical structure is wound. In this way, the second tab can cover the outwardly folded first tab, effectively avoiding the short circuit of the battery cell caused by the contact between the outwardly folded first tab and the battery shell when the battery cell is loaded into the battery shell, thereby ensuring the stability and consistency of the battery preparation process, and further facilitating the improvement of the yield of the battery.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cylindrical battery cell, an energy storage device, and an electrical device. Background Technology

[0002] Cylindrical batteries typically use current collectors welded to the tabs of the cell. To facilitate welding, the electrodes usually feature multiple narrow tabs, and after winding, the tabs are bent and flattened to keep the tab-side of the cell flat. However, since the current collectors are generally made of thin metal foil, the narrow tabs are prone to folding outwards during winding. This can cause the tabs to come into contact with the battery casing when the cell is installed, potentially leading to a short circuit. Utility Model Content

[0003] This application discloses a cylindrical battery cell, an energy storage device, and an electrical device. The second tab can wrap around the first tab inside the cylindrical battery cell, preventing the first tab from folding outward during the winding process, which would cause the battery cell to come into contact with the casing and cause a short circuit in the cylindrical battery cell. This ensures the stability and consistency of the battery manufacturing process and improves the yield of the battery.

[0004] To achieve the above objectives, in a first aspect, this application discloses a cylindrical battery cell, comprising:

[0005] Two electrodes, the two electrodes having opposite polarities; and

[0006] A diaphragm is separated between the two electrodes and wound to form a cylindrical structure;

[0007] The electrode includes:

[0008] The electrode body is a long strip-shaped sheet, and the electrode body has a winding start end and a winding end end along its length direction;

[0009] A tab assembly is provided at one end of the electrode body along its width direction. The tab assembly includes a first tab and a second tab arranged sequentially along a first direction. The first tab is located at the beginning of the winding and extends along the length direction of the electrode body. The second tab is located at the end of the winding and extends along the length direction of the electrode body. The dimension W1 of the second tab along its length direction satisfies: W1≥2πR, so that when the electrode and the diaphragm are wound to form the cylindrical structure, the second tab surrounds the outer periphery of the first tab.

[0010] Wherein, R is the radius of the cylindrical structure, and the first direction is from the beginning of the winding to the end of the winding.

[0011] By setting the dimension of the second tab along its length to satisfy W1≥2πR, the second tab can wrap around the outer periphery of the first tab. In this way, even if the first tab located at the beginning of the winding of the electrode body folds outward during the winding process, the second tab can still wrap around the first tab inside the cylindrical cell after winding. This allows the second tab to cover the folded-out first tab, effectively preventing the cell from folding outward and coming into contact with the battery casing when it is installed in the battery casing, thus preventing a short circuit. This ensures the stability and consistency of the battery manufacturing process, which in turn helps to improve the yield rate of the battery.

[0012] In some possible implementations, the dimension W1 of the second electrode along its length direction satisfies: 1mm+2πR≤W1≤7mm+2πR.

[0013] By limiting the length W1 of the second tab to satisfy: 1mm + 2πR ≤ W1 ≤ 7mm + 2πR, the length of the second tab is appropriate. This allows the second tab to more stably wrap around the first tab after winding, while avoiding waste or winding difficulties caused by an excessively large second tab. In practical applications, an appropriate value can be selected within the size range of the second tab based on factors such as the size of the cylindrical cell, the material of the electrode, and the battery manufacturing process to optimize battery performance and manufacturing efficiency.

[0014] When W1 < 1mm + 2πR, the second tab may have difficulty properly wrapping around the first tab, increasing the risk of the first tab flipping outwards, thus affecting the battery's stability and consistency. When W1 > 7mm + 2πR, the second tab is too large, increasing material costs and potentially causing difficulties during winding or stacking during the flattening process, thus affecting battery manufacturing efficiency and yield. Therefore, by appropriately setting the length W1 of the second tab, it is possible to optimize battery manufacturing efficiency and cost while ensuring battery performance.

[0015] In some possible implementations, the second electrode tab includes a plurality of second sub-electrodes, which are arranged sequentially along the first direction;

[0016] When the number N of the second sub-pole ears satisfies: N≥4, the dimension W2 of the second sub-pole ear along the first direction satisfies: W2≥0.5πR.

[0017] This design allows multiple second tabs to better adapt to the shape of the cylindrical cell after winding, enabling the cylindrical cell to be flattened better during the flattening process. This avoids the problem of increased volume and internal resistance of the cylindrical cell caused by the accumulation of multiple second tabs, thereby improving the stability and consistency of the cell.

[0018] In addition, this application can also ensure that the multiple second sub-tabs can also wrap around the first tab inside the cylindrical cell after winding, so that the multiple second sub-tabs can cover the outwardly folded first tab, effectively preventing the first tab from folding outward and causing the cell to come into contact with the battery casing when it is installed in the battery casing, thus causing a short circuit in the cylindrical cell, thereby ensuring the stability and consistency of the battery manufacturing process and improving the yield of the battery.

[0019] For example, N can be 4, 5, 6 or 7, etc., and W2 can be 0.5πR, 0.25mm+0.5πR, 0.5mm+0.5πR, 0.75mm+0.5πR, 1mm+0.5πR, 1.25mm+0.5πR, 1.5mm+0.5πR, 1.75mm+0.5πR, etc. The embodiments of this application do not limit this.

[0020] In some possible implementations, when the number N of the second sub-electrode satisfies: N≥4, the dimension W2 of the second sub-electrode along the length direction of the electrode body satisfies: 0.25mm+0.5πR≤W2≤1.75mm+0.5πR.

[0021] By limiting the size W2 of the second sub-electrode along its length to satisfy: 0.25mm+0.5πR≤W1≤1.75mm+0.5πR, the second sub-electrode can more stably wrap around the first sub-electrode after winding, while avoiding waste or winding difficulties caused by the second sub-electrode being too large.

[0022] When W2 < 0.25mm + 2πR, multiple second sub-tabs may have difficulty properly wrapping around the first tab, increasing the risk of the first tab flipping outwards, thus affecting the stability and consistency of the battery. Conversely, when W2 > 1.75mm + 2πR, the size of the second sub-tabs becomes too large, increasing material costs and potentially causing difficulties during winding or stacking during the flattening process, thus affecting battery manufacturing efficiency and yield. Therefore, by rationally setting the length dimension W2 of the second sub-tab, it is possible to optimize battery manufacturing efficiency and cost while ensuring battery performance.

[0023] In some possible implementations, the first electrode tab includes a plurality of first sub-electrodes, and the plurality of first sub-electrodes are arranged sequentially along the first direction;

[0024] Along the length of the electrode body, the size of the second sub-electrode is larger than the size of the first sub-electrode.

[0025] This design allows the first sub-tab to flip outwards during the winding process, as the larger size of the second sub-tab effectively wraps around it, further enhancing the stability and reliability of the cell structure. Simultaneously, the arrangement of multiple first and second sub-tabs improves the electrical connection between the tabs and the current collector, reduces contact resistance, and thus enhances the overall performance of the battery.

[0026] In some possible implementations, the second tab has a first side and a second side along the first direction, the second side being spaced apart from the edge of the winding end, and the first side being disposed adjacent to the first tab.

[0027] In other words, the second side of the second tab is spaced apart from the edge of the winding end, and the position of the tab assembly is left blank in this spaced area. This is so that after the electrode sheet is wound into a cylindrical structure, the diameter of the position where the tab assembly is located in the cylindrical structure is smaller than the diameter of the position where the electrode body is located in the cylindrical structure. This allows a certain amount of space to be reserved even after the first tab and / or the first tab is folded outward. This avoids the problem of the first or second tab folding outward, which could scratch the casing or cause a short circuit when the cylindrical cell enters the casing.

[0028] In some possible implementations, the first electrode tab has a third side and a fourth side along the first direction, the third side is spaced apart from the edge of the winding start end, the fourth side is disposed adjacent to the second electrode tab, and when the electrode sheet and the diaphragm are wound to form a cylindrical structure, a cell hole is formed at the winding center of the cylindrical structure.

[0029] It is understandable that, since the third side of the first tab is spaced apart from the edge of the winding start of the electrode body, the position of the tab assembly is left blank in this spaced area. After the electrode and separator are wound to form a cylindrical structure, a cell hole is formed at the winding center of the cylindrical structure. The first tab is a certain distance away from the cell hole, so that the first tab will not block the cell hole of the cylindrical cell. This is conducive to the subsequent injection of electrolyte through the cell hole, and at the same time avoids affecting the subsequent welding of the tab assembly to the battery casing, which is conducive to improving the yield of the battery.

[0030] In some possible implementations, the first electrode tab includes a plurality of first sub-electrodes, which are spaced apart along the first direction, and the size of the plurality of first sub-electrodes increases sequentially in the second direction along the first direction.

[0031] Wherein, the second direction is the width direction of the electrode body.

[0032] By setting the dimensions of the first tab to increase sequentially in the second direction, the first tab can be more evenly distributed on the inner side of the cylindrical cell during winding, avoiding cell structural instability caused by uneven first tab dimensions. Simultaneously, this design also improves the electrical connection performance between the first tab and the current collector, further reducing contact resistance and enhancing the overall battery performance.

[0033] Secondly, this application also discloses an energy storage device, including a housing and a cylindrical battery cell as described in the first aspect above.

[0034] The energy storage device with the cylindrical battery cell described in the first aspect above can also achieve the following: even if the first tab located at the beginning of the winding of the electrode body is folded outward during the winding process, the second tab can still wrap around the first tab inside the cylindrical battery cell after winding. This allows the second tab to cover the folded-out first tab, effectively preventing the battery cell from short-circuiting due to contact between the battery cell and the battery casing when the first tab is folded outward. This ensures the stability and consistency of the battery manufacturing process and helps to improve the yield of the battery.

[0035] Thirdly, this application also discloses an electrical device including the energy storage device described in the second aspect above.

[0036] Electrical equipment equipped with the energy storage device described in the second aspect above can also achieve the following: even if the first tab located at the beginning of the winding of the electrode body is folded outward during the winding process, the second tab can still wrap around the first tab inside the cylindrical cell after winding. This allows the second tab to cover the folded-out first tab, effectively preventing the cell from short-circuiting when it comes into contact with the battery casing during installation. This ensures the stability and consistency of the battery manufacturing process and helps improve the yield rate of the battery.

[0037] Compared with the prior art, the beneficial effects of this application are:

[0038] This application provides a cylindrical battery cell, an energy storage device, and an electrical appliance. The cylindrical battery cell includes two electrodes with opposite polarities and a separator. The separator is separated between the two electrodes and wound to form a cylindrical structure. The electrodes include an electrode body and a tab assembly. The tab assembly is located at one end of the electrode body along its width direction. The tab assembly includes a first tab and a second tab arranged sequentially along a first direction. The first tab is located at the beginning of the winding and extends along the length direction of the electrode body. The second tab is located at the end of the winding and extends along the length direction of the electrode body. The dimension W1 of the second tab along its length direction satisfies: W1≥2πR, so that when the second tab is wound to form a cylindrical structure, the second tab surrounds the outer periphery of the first tab. Therefore, even if the first tab at the beginning of the winding of the electrode body folds outward during the winding process, the second tab can still wrap around the first tab inside the cylindrical cell after winding. This allows the second tab to cover the folded-out first tab, effectively preventing the cell from folding outward and causing it to come into contact with the battery casing when it is installed in the battery casing, thus preventing a short circuit. This ensures the stability and consistency of the battery manufacturing process and helps to improve the yield rate of the battery. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the structure of a cylindrical battery cell in related technologies;

[0041] Figure 2 This is one of the structural schematic diagrams of the cylindrical battery cell disclosed in the embodiments of this application;

[0042] Figure 3 This is one of the schematic diagrams of the electrode structure disclosed in the embodiments of this application;

[0043] Figure 4 This is a second schematic diagram of the cylindrical battery cell disclosed in the embodiments of this application;

[0044] Figure 5 This is a second schematic diagram of the structure of the electrode sheet disclosed in the embodiments of this application;

[0045] Figure 6 This is a schematic diagram of the energy storage device disclosed in the embodiments of this application;

[0046] Figure 7 This is a schematic diagram of the structure of the electrical equipment disclosed in the embodiments of this application.

[0047] Explanation of reference numerals in the attached figures:

[0048] 100 - Cylindrical cell; 10a - Cell hole;

[0049] 10 - Electrode; 11 - Electrode body; 11a - Winding start; 11b - Winding end;

[0050] 12-Electrode group; 121-First electrode; 121a-Third side; 121b-Fourth side; 1211-First sub-electrode; 122-Second electrode; 122a-First side; 122b-Second side; 1221-Second sub-electrode;

[0051] 200 - Energy storage device; 201 - Housing;

[0052] 300 - Electrical equipment;

[0053] 301 - Power conversion device; 302 - First user load; 303 - Second user load;

[0054] X - Length direction; Y - Width direction; F1 - First direction. Detailed Implementation

[0055] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0056] In this application, the terms "above" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0057] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0058] Furthermore, the terms "set up," "equipped with," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0059] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0060] As a green and clean energy source, power batteries are environmentally friendly, efficient, and rechargeable, playing a vital role in the pursuit of lightweight and long-range applications in consumer electronics and in the new energy vehicle industry.

[0061] In the manufacturing process of cylindrical batteries, the welding process between the current collector and the cell tabs is a crucial step in ensuring battery performance and safety. To achieve efficient welding, the electrode design typically employs a multi-tab structure, that is, dividing a wide electrode into several narrow tabs. This design improves current conduction efficiency and provides operational space for subsequent processes. After the electrode is wound, the dispersed tabs are brought together towards the center through a bending process, and then flattened to form a regular plane, ultimately creating a flat cell end face, which facilitates subsequent welding to the current collector.

[0062] However, since the current collectors for electrodes are generally made of ultra-thin metal foils (such as aluminum or copper foil) with a thickness of only 10-20 micrometers, their mechanical strength is inherently limited. During high-speed winding, the edges of narrow electrode tabs (typically 2-5 millimeters wide) are highly susceptible to uncontrollable warping deformation due to centrifugal force. This microscopic deformation may be negligible on a single electrode tab, but when dozens of electrodes simultaneously experience a 1-2° deflection, the flatness of the entire electrode array will significantly deteriorate.

[0063] Even worse, in the process of cell assembly, such as Figure 1 As shown, when the flatness deviation of the tab array (a) exceeds 0.3 mm, some tabs (a) may break through the insulation gap and make accidental contact with the metal casing (b). Considering that the metal casing (b) of battery (m) is usually made of aluminum alloy with excellent conductivity, this contact will directly lead to a short circuit between the positive and negative electrodes. The high temperature generated at the moment of the short circuit (up to several hundred degrees Celsius) will not only melt the local tab structure, but may also trigger a chain reaction—the electrolyte decomposes to produce gas, causing the battery to swell, and in extreme cases, even thermal runaway.

[0064] In view of this, this application provides a cylindrical battery cell, an energy storage device, and an electrical device. When the tab near the beginning of the electrode sheet folds outward during the winding process, the second tab group can also wrap around the tab on the inner side of the cylindrical battery cell after winding, avoiding the tab from folding outward and causing a short circuit in the battery cell. This helps to ensure the stability and consistency of the battery cell welding process, thereby improving the yield of cylindrical batteries.

[0065] The technical solution of this application will be further described below with reference to the embodiments and accompanying drawings.

[0066] Please see Figures 2 to 3 , Figure 2 This is one of the structural schematic diagrams of the cylindrical battery cell disclosed in the embodiments of this application. Figure 3 This is one of the schematic diagrams of the electrode structure disclosed in the embodiments of this application. In a first aspect, the embodiments of this application disclose a cylindrical battery cell 100, which includes two electrodes 10 and a separator (not shown). The two electrodes 10 have opposite polarities, and the separator is separated between the two electrodes 10 with opposite polarities. The two electrodes 10 with opposite polarities and the separator are wound together to form a cylindrical structure.

[0067] For example, the cylindrical cell 100 may be a lithium-ion cell, a sodium-ion cell, a zinc-ion cell, etc., and the embodiments of this application do not limit it.

[0068] It is understood that, depending on different application requirements, the two electrodes 10 with opposite polarities can be positive and negative electrodes, respectively. The positive electrode is typically used in electrochemical oxidation reactions, serving as the positive electrode of the cylindrical cell 100, while the negative electrode is typically used in electrochemical reduction reactions, serving as the negative electrode of the cylindrical cell 100. The electrode 10 in this application can be either a positive or a negative electrode; this application does not specifically limit its application in this regard.

[0069] In some embodiments, the electrode 10 includes an electrode body 11, which is a strip-shaped sheet and has a winding start end 11a and a winding end end 11b along its length direction X.

[0070] In some embodiments, the electrode 10 includes a tab group 12, which is disposed at one end of the electrode body 11 along its width direction Y. The tab group 12 includes a first tab 121 and a second tab 122 sequentially disposed along a first direction F1. The first tab 121 is located at the winding start end 11a and extends along the length direction X of the electrode body 11, and the second tab 122 is located at the winding end end 11b and extends along the length direction X of the electrode body 11. The first direction F1 extends from the winding start end 11a to the winding end end 11b.

[0071] It is understood that, in the thickness direction of the electrode body 11, the electrode body 11 typically includes a current collector (not shown) and an electrode active layer (not shown, which may be provided on one side of the current collector or on both sides of the current collector) disposed on at least one surface of the current collector. The electrode body 11 is the portion of the electrode 10 with the electrode active layer, while the tab assembly 12 is the portion of the electrode 10 without the electrode active layer. The tab assembly 12 can be directly cut from the current collector, and the tab assembly 12 is typically used for electrical connection with external current collector components (e.g., adapter plates and electrode terminals) to conduct or conduct current. Specifically, the positive electrode 10 includes a positive current collector (e.g., aluminum foil) and a positive active material layer (e.g., ternary material, lithium iron phosphate, or lithium cobalt oxide) coated on the surface of the positive current collector. The negative electrode 10 includes a negative current collector (e.g., copper foil) and a negative active material layer (e.g., carbon or silicon) coated on the surface of the negative current collector.

[0072] Additionally, it should be noted that in this application, the electrode body 11 is elongated before being wound to form the cylindrical cell 100. The length dimension of the electrode body 11 is greater than the width dimension of the electrode body 11. The length direction X of the electrode body 11 is the winding direction of the electrode 10. The width direction Y of the electrode body 11 is perpendicular to the length direction X of the electrode body 11. The thickness direction (not shown) of the electrode body 11 is perpendicular to both the length direction X and the width direction Y of the electrode body 11.

[0073] Specifically, the electrode body 11 is wound from the winding start end 11a, that is, the first electrode tab 121 starts to be wound first, and then the second electrode tab 122 starts to be wound. In other words, when the two electrodes 10 and the diaphragm are wound to form a cylindrical structure, the second electrode tab 122 surrounds the outer periphery of the first electrode tab 121.

[0074] Optionally, the dimension W1 of the second electrode tab 122 along its length direction X satisfies: W1≥2πR, so that when the electrode 10 and the diaphragm are wound to form a cylindrical structure, the second electrode tab 122 surrounds the outer periphery of the first electrode tab 121. Wherein, R is the radius of the cylindrical structure. By setting the dimension of the second tab 122 along the length direction X to satisfy W1≥2πR, the second tab 122 can wrap around the outer periphery of the first tab 121. In this way, even if the first tab 121 located at the winding start 11a of the electrode body 11 folds outward during the winding process, the second tab 122 can still wrap around the first tab 121 inside the cylindrical cell 100 after winding. This allows the second tab 122 to cover the outwardly folded first tab 121, effectively preventing the first tab 121 from folding outward and causing the cell to contact the battery casing 201 when it is installed in the battery casing 201, thus preventing a short circuit in the cell. This ensures the stability and consistency of the battery manufacturing process and helps to improve the yield of the battery.

[0075] In some embodiments, the dimension W1 of the second electrode 122 along its length direction X satisfies: 1mm+2πR≤W1≤7mm+2πR. Optionally, this relationship may further satisfy 1mm+2πR≤W1≤2mm+2πR, 2mm+2πR≤W1≤3mm+2πR, 3mm+2πR≤W1≤4mm+2πR, 4mm+2πR≤W1≤5mm+2πR, 5mm+2πR≤W1≤6mm+2πR, and 6mm+2πR≤W1≤7mm+2πR. For example, W1 can be 1mm+2πR, 1.5mm+2πR, 2mm+2πR, 2.5mm+2πR, 3mm+2πR, 3.5mm+2πR, 4mm+2πR, 4.5mm+2πR, 5mm+2πR, 5.5mm+2πR, 6mm+2πR, 6.5mm+2πR, 7mm+2πR, etc.

[0076] By limiting the dimension W1 of the second tab 122 along its length direction X to satisfy: 1mm + 2πR ≤ W1 ≤ 7mm + 2πR, the length of the second tab 122 is appropriate. This allows the second tab 122 to more stably wrap around the first tab 121 after winding, while avoiding waste or winding difficulties caused by an excessively large second tab 122. In practical applications, an appropriate value can be selected within the size range of the second tab 122 based on factors such as the size of the cylindrical cell 100, the material of the electrode 10, and the battery manufacturing process, to optimize battery performance and manufacturing efficiency.

[0077] When W1 < 1mm + 2πR, the second tab 122 may have difficulty properly wrapping around the first tab 121, increasing the risk of the first tab 121 flipping outwards, thus affecting the stability and consistency of the battery. When W1 > 7mm + 2πR, the size of the second tab 122 is too large, not only increasing material costs but also potentially causing difficulties during winding, or causing the second tab 122 to accumulate during the flattening process, making it difficult to flatten, thus affecting the battery manufacturing efficiency and yield. Therefore, by reasonably setting the dimension W1 of the second tab 122 along its length X, it is possible to optimize the battery manufacturing efficiency and cost while ensuring battery performance.

[0078] In some embodiments, the second tab 122 has a first side 122a and a second side 122b along the first direction F1. The second side 122b is spaced apart from the edge of the winding end 11b, and the first side 122a is disposed adjacent to the first tab 121. That is, the second side 122b of the second tab 122 is spaced apart from the edge of the winding end 11b. The spaced area is used to leave the position of the tab assembly 12 blank, so that after the electrode sheet 10 is wound to form a cylindrical structure, the diameter of the position where the tab assembly 12 is located in the cylindrical structure is smaller than the diameter of the position where the electrode body 11 is located in the cylindrical structure. This allows a certain amount of space to be reserved even after the first tab 121 and / or folded outward, thereby avoiding the problem of the first tab 121 or the second tab 122 folding outward and causing the cylindrical cell 100 to scratch the housing 201 or short-circuit when it comes into contact with the housing 201.

[0079] In some embodiments, the first electrode tab 121 has a third side 121a and a fourth side 121b along the first direction F1. The third side 121a is spaced apart from the edge of the winding start end 11a, and the fourth side 121b is disposed adjacent to the second electrode tab 122. When the electrode sheet 10 and the diaphragm are wound to form a cylindrical structure, a cell hole 10a is formed at the winding center of the cylindrical structure. It is understandable that, since the third side 121a of the first tab 121 is spaced apart from the edge of the winding start 11a of the electrode body 11, the position of the tab assembly 12 is left blank in this spaced area. After the electrode 10 and the separator are wound to form a cylindrical structure, the center of the cylindrical structure has a cell hole 10a. The first tab 121 is a certain distance away from the cell hole 10a, so that after the electrode 10 is wound to form a cylindrical structure, the first tab 121 will not block the cell hole of the cylindrical cell 100. This is beneficial for subsequent electrolyte injection and avoids affecting the subsequent welding of the tab assembly 12 to the battery casing 201, which is beneficial for improving the yield of the battery.

[0080] In some embodiments, the first tab 121 includes a plurality of first sub-tabs 1211, which are spaced apart along a first direction F1. Along the first direction F1, the dimensions of the plurality of first sub-tabs 1211 increase sequentially in a second direction. The second direction is the width direction Y of the electrode body 11. By setting the dimensions of the first sub-tabs 1211 to increase sequentially in the second direction, the first tabs 121 can be more evenly distributed on the inner side of the cylindrical cell 100 during winding, avoiding cell structure instability caused by uneven dimensions of the first tabs 121. Simultaneously, this design also helps improve the electrical connection performance between the first tabs 121 and the current collector, further reducing contact resistance and improving the overall performance of the battery.

[0081] Please see Figures 4 to 5 , Figure 4This is the second schematic diagram of the cylindrical battery cell disclosed in the embodiments of this application. Figure 5 This is a second schematic diagram of the electrode structure disclosed in this application. In some embodiments, the second electrode tab 122 includes a plurality of second sub-electrodes 1221, which are sequentially arranged along a first direction F1. When the number N of the second sub-electrodes 1221 satisfies N≥4, the dimension W2 of the second sub-electrodes 1221 along the first direction F1 satisfies W2≥0.5πR. This design allows the plurality of second sub-electrodes 1221 to better adapt to the shape of the cylindrical cell 100 after winding, enabling the cylindrical cell 100 to be flattened better during the flattening process. This avoids the problem of increased volume and internal resistance of the cylindrical cell 100 caused by the accumulation of the plurality of second sub-electrodes 1221, thereby improving the stability and consistency of the cell.

[0082] In addition, this application can also ensure that the multiple second tabs 1221 can also wrap around the first tab 121 inside the cylindrical cell 100 after winding, so that the multiple second tabs 1221 can cover the outwardly folded first tab 121, effectively avoiding the situation where the first tab 121 folds outward and the cell comes into contact with the battery housing 201 when it is installed into the battery housing 201, causing a short circuit in the cylindrical cell 100, thereby ensuring the stability and consistency of the battery manufacturing process and improving the yield of the battery.

[0083] For example, N can be 4, 5, 6 or 7, etc., and W2 can be 0.5πR, 0.25mm+0.5πR, 0.5mm+0.5πR, 0.75mm+0.5πR, 1mm+0.5πR, 1.25mm+0.5πR, 1.5mm+0.5πR, 1.75mm+0.5πR, etc. The embodiments of this application do not limit this.

[0084] In some embodiments, when the number N of the second sub-tabs 1221 satisfies: N≥4, the dimension W2 of the second sub-tab 1221 along the length direction X of the electrode body 11 satisfies: 0.25mm+0.5πR≤W2≤1.75mm+0.5πR.

[0085] For example, N can be 4, 5, 6 or 7, etc., and W2 can be 0.25mm+0.5πR, 0.5mm+0.5πR, 0.75mm+0.5πR, 1mm+0.5πR, 1.25mm+0.5πR, 1.5mm+0.5πR, 1.75mm+0.5πR, etc. The embodiments of this application do not limit this.

[0086] By limiting the size W2 of the second sub-taper 1221 along its length direction X to satisfy: 0.25mm+0.5πR≤W1≤1.75mm+0.5πR, the second sub-taper 122 can more stably wrap around the first sub-taper 121 after winding, while avoiding waste or winding difficulties caused by the second sub-taper 122 being too large.

[0087] When W2 < 0.25mm + 2πR, multiple second sub-tabs 1221 may have difficulty properly wrapping around the first tab 121, increasing the risk of the first tab 121 flipping outwards, thus affecting the stability and consistency of the battery. When W2 > 1.75mm + 2πR, the size of the second sub-tabs 1221 is too large, not only increasing material costs but also potentially causing difficulties during winding, or causing multiple second sub-tabs 1221 to pile up during the flattening process, making flattening difficult and affecting the battery's manufacturing efficiency and yield. Therefore, by reasonably setting the dimension W2 of the second sub-tab along its length direction X, it is possible to optimize the battery's manufacturing efficiency and cost while ensuring battery performance.

[0088] In some embodiments, the first tab 121 includes a plurality of first sub-tabs 1211, which are sequentially arranged along a first direction F1. In the longitudinal direction X of the electrode body 11, the size of the second sub-tab 1221 is larger than that of the first sub-tab 1211. This design allows the second sub-tab 1221 to effectively wrap around the folded first tab 121 during winding, even if it flips outward, further enhancing the stability and reliability of the cell structure due to the larger size of the second sub-tab 1221. Simultaneously, the arrangement of multiple first sub-tabs 1211 and multiple second tabs 1221 also improves the electrical connection performance between the tab and the current collector, reduces contact resistance, and thus improves the overall performance of the battery.

[0089] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of the energy storage device disclosed in the embodiments of this application. In a second aspect, this application also discloses an energy storage device 200, including a housing 201 and a cylindrical battery cell 100 as described in the first aspect above.

[0090] The energy storage device 200 having the cylindrical cell 100 described in the second aspect above can also achieve that even if the first tab 121 located at the winding start end 11a of the electrode body 11 folds outward during the winding process, the second tab 122 can still wrap around the first tab 121 inside the cylindrical cell 100 after winding. This allows the second tab 122 to cover the outwardly folded first tab 121, effectively preventing the first tab 121 from folding outward and causing the cell to come into contact with the battery casing 201 when it is installed in the battery casing 201, thus preventing a short circuit in the cell. This ensures the stability and consistency of the battery manufacturing process and helps to improve the yield of the battery.

[0091] Optionally, the energy storage device 200 may include, but is not limited to, energy storage applications such as energy storage power stations, hydropower / thermal / wind power generation systems, solar power generation systems, mobile power systems, smart home systems, or temporary power supply systems, and may also be applied in multiple fields such as data centers, military equipment, aerospace, charging piles, and electric vehicles.

[0092] Optionally, the energy storage device 200 may include, but is not limited to, individual batteries, or battery modules, battery packs, battery clusters, mobile power supplies, energy storage cabinets / containers, and other battery integrated systems composed of individual batteries. The actual application form of the energy storage device 200 provided in this application embodiment may be, but is not limited to, the listed products, and may also be other application forms. This application embodiment does not strictly limit the application form of the energy storage device 200.

[0093] Optionally, when the energy storage device 200 is a single cell, the energy storage device 200 can be a cylindrical cell.

[0094] Optionally, the single cell can be a rechargeable battery, which refers to a single cell that can be recharged after discharge to activate the active materials and continue to be used. The single cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application does not specifically limit it.

[0095] Please see Figure 7 , Figure 7 This is a schematic diagram of the structure of the electrical equipment disclosed in the embodiments of this application. In a fourth aspect, this application also discloses an electrical equipment 300, including the energy storage device 200 as described in the third aspect above.

[0096] The electrical device 300 having the energy storage device 200 described in the third aspect above can also achieve the following: even if the first tab 121 located at the winding start 11a of the electrode body 11 folds outward during the winding process, the second tab 122 can still wrap around the first tab 121 inside the cylindrical cell 100 after winding. This allows the second tab 122 to cover the outwardly folded first tab 121, effectively preventing the first tab 121 from folding outward and causing the cell to come into contact with the battery casing 201 when it is installed in the battery casing 201, thus preventing a short circuit in the cell. This ensures the stability and consistency of the battery manufacturing process and helps to improve the yield of the battery.

[0097] This application uses a home energy storage scenario in electrical equipment 300 as an example for illustration, but the electrical equipment 300 in this application is not limited to the home energy storage scenario.

[0098] This application provides an electrical device 300, which includes a power conversion device 301 (photovoltaic panel), a first user load 302 (household lighting fixture), a second user load 303 (e.g., household appliances such as air conditioners), and an energy storage device 200. The energy storage device 200 is a small energy storage box that can be wall-mounted on an outdoor wall. However, the energy storage device is not limited to wall mounting and can also be placed in a user's residence in other ways. Specifically, the photovoltaic panel can convert solar energy into electrical energy during periods of low electricity prices, and the energy storage device 200 stores this electrical energy and supplies it to lighting fixtures and household appliances during peak electricity prices, or provides power during power outages / outages.

[0099] Optionally, the energy storage device 200 may include multiple devices. For example, the energy storage device 200 may be two, three, four, five, six, etc., and this application embodiment does not limit this.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A cylindrical battery cell, characterized in that, The cylindrical battery cell includes: Two electrodes, the two electrodes having opposite polarities; and A diaphragm is separated between the two electrodes and wound to form a cylindrical structure; The electrode includes: The electrode body is a long strip-shaped sheet, and the electrode body has a winding start end and a winding end end along its length direction; A tab assembly is provided at one end of the electrode body along its width direction. The tab assembly includes a first tab and a second tab arranged sequentially along a first direction. The first tab is located at the beginning of the winding and extends along the length direction of the electrode body. The second tab is located at the end of the winding and extends along the length direction of the electrode body. The dimension W1 of the second tab along its length direction satisfies: W1≥2πR, so that when the electrode and the diaphragm are wound to form the cylindrical structure, the second tab surrounds the outer periphery of the first tab. Wherein, R is the radius of the cylindrical structure, and the first direction is from the beginning of the winding to the end of the winding.

2. The cylindrical battery cell according to claim 1, characterized in that, The second electrode ear's length dimension W1 satisfies: 1mm+2πR≤W1≤7mm+2πR.

3. The cylindrical battery cell according to claim 1, characterized in that, The second electrode includes a plurality of second sub-electrodes, which are arranged sequentially along the first direction; When the number N of the second sub-pole ears satisfies: N≥4, the dimension W2 of the second sub-pole ear along the first direction satisfies: W2≥0.5πR.

4. The cylindrical battery cell according to claim 3, characterized in that, When the number N of the second sub-electrode satisfies: N≥4, the dimension W2 of the second sub-electrode along the length direction of the electrode body satisfies: 0.25mm+0.5πR≤W2≤1.75mm+0.5πR.

5. The cylindrical battery cell according to claim 3, characterized in that, The first electrode includes a plurality of first sub-electrodes, which are arranged sequentially along the first direction; Along the length of the electrode body, the size of the second sub-electrode is larger than the size of the first sub-electrode.

6. The cylindrical battery cell according to any one of claims 1-4, characterized in that, The first electrode includes a plurality of first sub-electrodes, which are spaced apart along the first direction, and the size of the plurality of first sub-electrodes increases sequentially in the second direction along the first direction. Wherein, the second direction is the width direction of the electrode body.

7. The cylindrical battery cell according to any one of claims 1-5, characterized in that, The second electrode tab has a first side and a second side along the first direction, the second side being spaced apart from the edge of the winding end, and the first side being disposed adjacent to the first electrode tab.

8. The cylindrical battery cell according to any one of claims 1-5, characterized in that, The first electrode tab has a third side and a fourth side along the first direction. The third side is spaced apart from the edge of the winding start end, and the fourth side is disposed adjacent to the second electrode tab. When the electrode sheet and the diaphragm are wound to form a cylindrical structure, a cell hole is formed at the winding center of the cylindrical structure.

9. An energy storage device, characterized in that, It includes a housing and a cylindrical battery cell as described in any one of claims 1-8.

10. An electrical appliance, characterized in that, Includes the energy storage device as described in claim 9.

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