Battery cell, battery, and electric device

Abstract

A battery cell (200), a battery (300), and an electrical device are provided. The battery cell (200) includes an electrode (100), which includes an electrode body (10) and a tab (20). The electrode body (10) includes a current collector (11) and an active material layer (12). The current collector (11) is connected to the tab (20). The active material layer (12) is disposed on the outer surface of the current collector (11). The electrode body (10) has a pore structure (13) extending along the thickness direction of the electrode (100).

Description

Battery cells, batteries, and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202323209965.5 and application date of November 24, 2023, and claims the priority of the above-mentioned Chinese patent application. The entire content of the above-mentioned Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of batteries, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] In related technologies, the energy density of battery cells is improved by increasing the density of the electrode sheets. As the density of the electrode sheets increases, the elongation of the electrode sheets increases significantly. Due to the different thicknesses of the electrode tabs (i.e., the uncoated area) and the coated area (i.e., the area coated with the active material layer), cold pressing can cause an elongation difference between the coated area and the tabs, which can easily cause the tabs to have wavy edges or cracks.

[0005] Summary of the Invention

[0006] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, one purpose of the present application is to propose a battery cell, which can reduce the extension difference between the tab and the tab body when the tab is cold-pressed, thereby reducing the risk of wavy edges and cracking of the tab.

[0008] Another object of the present application is to provide a battery.

[0009] Another object of the present application is to provide an electrical device.

[0010] In a first aspect, an embodiment of the present application provides a battery cell, comprising:

[0011] The pole piece includes a pole piece body and a pole ear. The pole piece body includes a current collector and an active material layer. The current collector is connected to the pole ear. The active material layer is arranged on the outer surface of the current collector. The pole piece body has a pore structure extending along the thickness direction of the pole piece.

[0012] According to the battery cell of the present application, the pole piece body has a hole structure, and the area of ​​the pole piece body provided with the hole structure has a loose structure. During cold pressing, the compaction of the area of ​​the pole piece body provided with the hole structure is smaller than the compaction of the area of ​​the pole piece body not provided with the hole structure. The cold pressing extension forms a decrease from the pole piece body to the hole structure area, which can reserve a larger extension processing area for the pole ear, reduce the extension difference between the pole ear and the pole piece body, and reduce the risk of wavy edges and cracking of the pole ear, thereby improving the quality of the battery cell product and helping to improve the energy density of the battery cell.

[0013] In a second aspect, an embodiment of the present application further provides a battery comprising the above-mentioned battery cell.

[0014] The battery according to the present application includes the above-mentioned battery monomer, thereby improving the quality of the battery product and facilitating the improvement of the energy density of the battery.

[0015] In a third aspect, an embodiment of the present application further provides an electrical device comprising the above-mentioned battery.

[0016] The electrical device according to the present application includes the above-mentioned battery, thereby improving the product quality of the electrical device.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0019] FIG2 is an exploded view of the structure of a battery provided in some embodiments of the present application;

[0020] FIG3 is a schematic diagram of a battery cell provided in some embodiments of the present application;

[0021] FIG4 is a schematic diagram of a current collector provided with a pore structure according to some embodiments of the present application;

[0022] FIG5 is a schematic diagram showing that the current collector and the active material layer are both provided with pore structures according to some other embodiments of the present application;

[0023] FIG6 is a schematic diagram of an active material layer provided with a pore structure according to some other embodiments of the present application;

[0024] FIG7 is a schematic diagram of a pole piece provided with a group of hole groups according to some embodiments of the present application;

[0025] FIG8 is a schematic diagram of a pole piece provided with multiple groups of holes according to some embodiments of the present application;

[0026] FIG9 is an enlarged view of point C in FIG7 . DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0029] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0031] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0032] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0033] The term "plurality" used in this application refers to two or more (including two).

[0034] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0035] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or battery pack. A battery generally includes a casing that encloses one or more battery cells or multiple battery modules. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0036] A battery cell includes a casing, an electrode assembly, and an electrolyte. The casing is used to hold the electrode assembly and the electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer. The positive electrode collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet consists of a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector uncoated with the negative active material layer protrudes from the negative current collector coated with the negative active material layer. The negative current collector uncoated with the negative active material layer serves as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon, silicon, or other materials. To ensure that high currents can pass without melting, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together.

[0037] The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound structure or a laminated structure, but the embodiments of the present application are not limited thereto.

[0038] New energy vehicles have experienced rapid growth in recent years. Within the electric vehicle sector, power batteries, as the power source, play an irreplaceable and important role. A battery consists of a housing and multiple cells housed within it. As a core component in new energy vehicles, batteries have high requirements for both safety and cycle life.

[0039] In typical battery cells, the energy density of a battery cell is improved by increasing the density of the pole pieces. As the density of the pole pieces increases, the elongation of the pole pieces increases significantly. Due to the different thicknesses of the pole piece's tab (i.e., the uncoated area) and the coated area (i.e., the area coated with the active material layer), cold pressing can cause an elongation difference between the coated area and the tab, which can easily lead to wavy edges or cracks in the tab.

[0040] Based on the above considerations, in order to solve the problem of wavy edges or cracks in the tabs caused by the extension difference between the coating area and the tabs, a pole piece is designed. The pole piece includes a pole piece body and a tab. The pole piece body includes a current collector and an active material layer. The current collector is connected to the tab. The active material layer is provided on the outer surface of the current collector. The pole piece body has a pore structure extending along the thickness direction of the pole piece. During cold pressing, the compaction of the area of ​​the pole piece body with the pore structure is smaller than the compaction of the area of ​​the pole piece body without the pore structure. The cold pressing extension forms a gradual decrease from the pole piece body to the pore structure area, which can reserve a larger extension processing area for the tab, reduce the extension difference between the tab and the pole piece body, and reduce the risk of wavy edges and cracks in the tab.

[0041] The batteries disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery thermal management system disclosed in this application and batteries can be used to form such electrical devices. This helps expand the scope of application of the battery thermal management system and reduces the difficulty of assembling the battery thermal management system.

[0042] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0043] For the convenience of description, the following embodiments are described by taking a vehicle 400 as an example of an electrical device according to an embodiment of the present application.

[0044] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 400 provided in some embodiments of the present application. The vehicle 400 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 300 is provided inside the vehicle 400, and the battery 300 can be provided at the bottom, head or tail of the vehicle 400. The battery 300 can be used to power the vehicle 400. For example, the battery 300 can serve as an operating power source for the vehicle 400. The vehicle 400 may also include a controller 500 and a motor 600. The controller 500 is used to control the battery 300 to power the motor 600, for example, for starting, navigating and driving the vehicle 400.

[0045] In some embodiments of the present application, the battery 300 can serve not only as an operating power source for the vehicle 400 , but also as a driving power source for the vehicle 400 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 400 .

[0046] Please refer to Figure 2, which is an exploded view of the structure of the battery 300 provided in some embodiments of the present application. The battery 300 includes a box body 301 and a plurality of battery cells 200, and the battery cells 200 are used to be accommodated in the box body 301. Among them, the box body 301 is used to provide an assembly space for the battery cells 200, and the box body 301 can adopt a variety of structures. In some embodiments, the box body 301 may include a first box body 3011 and a second box body 3012, and the first box body 3011 and the second box body 3012 cover each other, and the first box body 3011 and the second box body 3012 jointly define an assembly space for accommodating the battery cells 200. The second box body 3012 can be a hollow structure with one end open, and the first box body 3011 can be a plate-like structure, with the first box body 3011 covering the open side of the second box body 3012, so that the first box body 3011 and the second box body 3012 jointly define an assembly space; the first box body 3011 and the second box body 3012 can also be hollow structures with one end open, with the open side of the first box body 3011 covering the open side of the second box body 3012. Of course, the box body 301 formed by the first box body 3011 and the second box body 3012 can be of various shapes, such as a cylinder, a cuboid, etc.

[0047] In the battery 300, multiple battery cells 200 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to multiple battery cells 200 being connected both in series and in parallel. Multiple battery cells 200 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery 300 structure can be housed within the housing 301. Alternatively, the battery 300 can be constructed by first connecting multiple battery cells 200 in series, in parallel, or in a hybrid configuration to form a battery 300 module. Multiple battery modules 300 can then be connected in series, in parallel, or in a hybrid configuration to form a single unit housed within the housing 301. The battery 300 can also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 200.

[0048] The pole piece 100 according to an embodiment of the present application is described below with reference to FIG. 3 to FIG. 9 . The pole piece 100 is a component of the battery cell 200 .

[0049] According to some embodiments of the present application, the present application provides a pole piece 100, comprising: a pole piece body 10 and a pole ear 20, the pole piece body 10 comprising a current collector 11 and an active material layer 12, the current collector 11 is connected to the pole ear 20, the active material layer 12 is arranged on the outer surface of the current collector 11, and the pole piece body 10 has a pore structure 13 extending along the thickness direction of the pole piece 100.

[0050] Among them, the pole piece 100 includes a pole piece body 10 and a pole tab 20. The pole piece body 10 is a coating area. In other words, the pole piece body 10 is the area where the current collector 11 is coated with the active material layer 12, and the pole tab 20 is the area where the current collector 11 is not coated with the active material layer 12. The current collector 11 is connected to the pole tab 20, and the current collector 11 and the pole tab 20 can be formed as one piece. The current collector 11 has a first surface and a second surface that are arranged opposite to each other. The first surface and the second surface are both coated with the active material layer 12, and the current collector 11 is located between the two layers of active material layers 12. The pole piece body 10 has a hole structure 13 extending along the thickness direction of the pole piece 100. The thickness direction of the pole piece 100 refers to the Z direction in Figure 4. The hole structure 13 can be formed on the pole piece body 10 by laser drilling. The structure of the area where the pole piece body 10 is provided with the hole structure 13 is looser than the structure of the area where the pole piece body 10 is not provided with the hole structure 13. During cold pressing, the compaction of the area where the pole piece body 10 is provided with the hole structure 13 is smaller than the compaction of the area where the pole piece body 10 is not provided with the hole structure 13. The cold pressing extension forms a decrease from the pole piece body 10 to the hole structure 13 area. The hole structure 13 can absorb the extension of the pole piece body 10 and reserve a larger extension processing area for the pole ear 20, reducing the extension difference between the pole ear 20 and the pole piece body 10, and reducing the risk of wavy edges and cracking of the pole ear 20.

[0051] In the above technical solution, the pole piece body 10 has a hole structure 13, and the region of the pole piece body 10 provided with the hole structure 13 has a loose structure. During cold pressing, the compaction of the region of the pole piece body 10 provided with the hole structure 13 is smaller than the compaction of the region of the pole piece body 10 not provided with the hole structure 13. The cold pressing extension forms a gradual decrease from the pole piece body 10 to the hole structure 13 region, which can reserve a larger extension processing area for the pole ear 20, reduce the extension difference between the pole ear 20 and the pole piece body 10, and reduce the risk of wavy edges and cracking of the pole ear 20.

[0052] According to some embodiments of the present application, as shown in FIG. 4 to FIG. 6 , the current collector 11 and / or the active material layer 12 is formed with a porous structure 13 .

[0053] Among them, the current collector 11 and / or the active material layer 12 form a porous structure 13, which can also be understood as, as shown in Figure 4, the current collector 11 forms a porous structure 13. Or as shown in Figure 6, the active material layer 12 forms a porous structure 13. Or as shown in Figure 5, both the current collector 11 and the active material layer 12 form a porous structure 13. This application is explained by taking the example of both the current collector 11 and the active material layer 12 forming a porous structure 13. When the current collector 11 and the two layers of active material layers 12 are formed with a porous structure 13, the porous structure 13 can pass through the pole piece body 10 along the thickness direction of the pole piece 100, and the porous structure 13 can be formed on the pole piece body 10 by laser drilling, thereby facilitating the formation of the porous structure 13 on the pole piece body 10, which is beneficial to improving the production efficiency of the pole piece 100. Or when the current collector 11 and a layer of active material layer 12 are formed with a porous structure 13, the porous structure 13 can be formed on the current collector 11 and the active material layer 12 by laser drilling. It should be noted that the pore structure 13 on the current collector 11 and the pore structure 13 on the active material layer 12 can be arranged directly opposite each other, or the pore structure 13 on the current collector 11 and the pore structure 13 on the active material layer 12 can be staggered. If both active material layers 12 are formed with pore structures 13, the pore structures 13 on the two active material layers 12 can be arranged directly opposite each other, or the pore structures 13 on the two active material layers 12 can be staggered.

[0054] In the above technical solution, the current collector 11 and / or the active material layer 12 forms a porous structure 13, which is conducive to making the structure of the area of ​​the pole piece body 10 provided with the porous structure 13 loose. During cold pressing, the compaction of the area of ​​the pole piece body 10 provided with the porous structure 13 is smaller than the compaction of the area of ​​the pole piece body 10 not provided with the porous structure 13. The cold pressing extension forms a gradual decrease from the pole piece body 10 to the porous structure 13 area, which is conducive to reserving a larger extension processing area for the pole ear 20, reducing the extension difference between the pole ear 20 and the pole piece body 10, and reducing the risk of wavy edges and cracking of the pole ear 20.

[0055] According to some embodiments of the present application, as shown in FIG. 7 and FIG. 8 , the pole piece body 10 has a hole setting area 14 adjacent to the pole tab 20 , and the hole setting area 14 has a hole structure 13 .

[0056] The hole setting area 14 refers to the area where the hole structure 13 can be set on the pole piece body 10, and the hole structure 13 is set in the hole setting area 14. The hole setting area 14 is arranged adjacent to the pole lug 20. In other words, the hole setting area 14 is located at a position of the pole piece body 10 adjacent to the pole lug 20, and the hole setting area 14 is located at the edge of the pole piece body 10. By arranging the hole structure 13 in the hole setting area 14, the hole structure 13 can be arranged close to the pole lug 20, so that a certain extension gradient is formed from the pole piece body 10 to the pole lug 20. The hole structure 13 can provide a certain amount of additional extension space for the pole lug 20, which can further reduce the extension difference between the pole lug 20 and the pole piece body 10, further reduce the risk of wavy edges and cracking of the pole lug 20, and by arranging the hole structure 13 in the hole setting area 14, a molten pool can be formed at the edge of the pole piece body 10, thereby strengthening the strength of the edge of the pole piece body 10 and reducing the risk of cracking at the edge of the pole piece body 10.

[0057] In the above technical solution, by setting the hole structure 13 in the hole setting area 14, the hole structure 13 can be set close to the pole lug 20, so that a certain extension gradient is formed from the pole piece body 10 to the pole lug 20. The hole structure 13 can provide a certain additional extension space for the pole lug 20, which can further reduce the extension difference between the pole lug 20 and the pole piece body 10, further reduce the risk of wavy edges and cracking of the pole lug 20, and form a molten pool at the edge of the pole piece body 10, thereby strengthening the strength of the edge of the pole piece body 10 and reducing the risk of cracking at the edge of the pole piece body 10.

[0058] According to some embodiments of the present application, as shown in Figures 7 and 8, along the arrangement direction of the pole piece body 10 and the pole tab 20, the spacing distance between the edge of the hole setting area 14 adjacent to the pole tab 20 and the edge away from the pole tab 20 is greater than 0 mm and less than or equal to 20 mm.

[0059] Among them, the arrangement direction of the pole piece body 10 and the pole ear 20 refers to the X direction in Figure 7, and the arrangement direction of the pole piece body 10 and the pole ear 20 is perpendicular to the thickness direction of the pole piece 100. Along the arrangement direction of the pole piece body 10 and the pole ear 20, the width dimension of the hole setting area 14 is D1, which satisfies the relationship: 0mm<D1≤20mm. For example, the width dimension of the hole setting area 14 can be 1mm, 5mm, 10mm, 20mm and other values. By setting the width of the hole setting area 14 to be greater than 0 mm and less than or equal to 20 mm, a hole structure 13 is set within a 20 mm width range of the pole piece body 10 near the edge of the pole lug 20. This can provide a certain amount of additional extension space for the pole lug 20, which is beneficial to reducing the punching area on the pole piece body 10. The size setting range of the hole setting area 14 can be reasonable, which is beneficial to reducing the processing steps and reducing the damage to the pole piece body 10. In addition, a molten pool can be formed at the edge of the pole piece body 10, further strengthening the strength of the edge of the pole piece body 10 and further reducing the risk of cracking at the edge of the pole piece body 10.

[0060] In the above technical solution, by setting the width dimension of the hole setting area 14 to be greater than 0 mm and less than or equal to 20 mm, the hole structure 13 is set within a 20 mm width range of the pole piece body 10 near the edge of the pole lug 20. This can provide a certain amount of additional extension space for the pole lug 20, which is beneficial to reducing the punching area on the pole piece body 10. The size setting range of the hole setting area 14 can be reasonable, which is beneficial to reducing the processing steps and reducing the damage to the pole piece body 10. In addition, a molten pool can be formed at the edge of the pole piece body 10, further strengthening the strength of the edge of the pole piece body 10 and further reducing the risk of cracking at the edge of the pole piece body 10.

[0061] According to some embodiments of the present application, along the arrangement direction of the pole piece body 10 and the pole tab 20 , the spacing distance between the edge of the hole setting area 14 adjacent to the pole tab 20 and the edge away from the pole tab 20 is greater than 0 mm and less than or equal to 10 mm.

[0062] Among them, the arrangement direction of the pole piece body 10 and the pole ear 20 refers to the X direction in Figure 7, and the arrangement direction of the pole piece body 10 and the pole ear 20 is perpendicular to the thickness direction of the pole piece 100. Along the arrangement direction of the pole piece body 10 and the pole ear 20, the width dimension of the hole setting area 14 is D1, which satisfies the relationship: 0mm<D1≤10mm. For example, the width dimension of the hole setting area 14 can be 1mm, 5mm, 10mm and other values. This application takes the width dimension of the hole setting area 14 as 10mm as an example for explanation. By setting the width of the hole setting area 14 to be greater than 0 mm and less than or equal to 10 mm, a hole structure 13 is set within a 10 mm width range of the pole piece body 10 near the edge of the pole lug 20. This can provide a certain amount of additional extension space for the pole lug 20, which is more conducive to reducing the punching area on the pole piece body 10. The size setting range of the hole setting area 14 can be reasonable, which is conducive to reducing the processing steps and reducing the damage to the pole piece body 10. In addition, a molten pool can be formed at the edge of the pole piece body 10, further strengthening the strength of the edge of the pole piece body 10 and further reducing the risk of cracking at the edge of the pole piece body 10.

[0063] In the above technical solution, by setting the width dimension of the hole setting area 14 to be greater than 0 mm and less than or equal to 10 mm, the hole structure 13 is set within a 10 mm width range of the pole piece body 10 near the edge of the pole lug 20. This can provide a certain amount of additional extension space for the pole lug 20, which is more conducive to reducing the punching area on the pole piece body 10. The size setting range of the hole setting area 14 can be made more reasonable, which is conducive to reducing the processing steps and reducing the damage to the pole piece body 10. In addition, a molten pool can be formed at the edge of the pole piece body 10, further strengthening the strength of the edge of the pole piece body 10 and further reducing the risk of cracking at the edge of the pole piece body 10.

[0064] According to some embodiments of the present application, as shown in Figures 7 and 8, there are multiple hole structures 13, and the multiple hole structures 13 form at least one hole group 30. The hole group 30 includes multiple hole structures 13. The multiple hole structures 13 in each hole group 30 are arranged along the first direction of the pole piece 100. The first direction, the thickness direction of the pole piece 100, and the arrangement direction of the pole piece body 10 and the pole ear 20 are perpendicular to each other.

[0065] Among them, the hole structure 13 can be set to multiple, and the multiple hole structures 13 form at least one hole group 30, each hole group 30 includes multiple hole structures 13, and the multiple hole structures 13 in each hole group 30 are arranged along the first direction of the pole piece 100. The first direction of the pole piece 100 refers to the Y direction in Figure 7, and the arrangement direction of the pole piece body 10 and the pole ear 20, the first direction and the thickness direction of the pole piece 100 are perpendicular to each other. Since cold pressing is performed along the direction of the tape, cold pressing is performed along the first direction, so the pole piece body 10 requires a larger extension along the first direction. By arranging the multiple hole structures 13 in each hole group 30 along the first direction of the pole piece 100, it is beneficial to reduce the extension of the pole piece body 10. During cold pressing, the compression of the area where the hole structure 13 is provided on the pole piece body 10 is smaller than the compression of the area where the hole structure 13 is not provided on the pole piece body 10. The cold pressing extension forms a decrease from the pole piece body 10 to the hole structure 13 area, which can reserve a larger extension processing area for the pole ear 20, further reducing the extension difference between the pole ear 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole ear 20.

[0066] In the above technical solution, by arranging the multiple hole structures 13 in each hole group 30 along the first direction of the pole piece 100, it is beneficial to reduce the elongation of the pole piece body 10. During cold pressing, the compression of the area of ​​the pole piece body 10 with the hole structure 13 is smaller than the compression of the area of ​​the pole piece body 10 without the hole structure 13. The cold pressing extension forms a decrease from the pole piece body 10 to the hole structure 13 area, which can reserve a larger extension processing area for the pole ear 20, further reduce the extension difference between the pole ear 20 and the pole piece body 10, and further reduce the risk of wavy edges and cracking of the pole ear 20.

[0067] According to some embodiments of the present application, as shown in FIG. 8 , the plurality of hole structures 13 form a plurality of hole groups 30 , and the plurality of hole groups 30 are arranged along the arrangement direction of the pole piece body 10 and the pole tab 20 .

[0068] Among them, the pole piece body 10 has a plurality of hole structures 13, and the plurality of hole structures 13 form a plurality of hole groups 30. The plurality of hole groups 30 are arranged along the arrangement direction of the pole piece body 10 and the pole tab 20. The arrangement direction of the pole piece body 10 and the pole tab 20, the first direction, and the thickness direction of the pole piece 100 are perpendicular to each other. The plurality of hole groups 30 are sequentially spaced apart along the arrangement direction of the pole piece body 10 and the pole tab 20. The plurality of hole structures 13 in each hole group 30 are sequentially arranged along the first direction of the pole piece 100. By providing a plurality of hole structures 13, the number of hole structures 13 on the pole piece body 10 can be increased, which is more conducive to reducing the extension of the pole piece body 10, further reducing the extension difference between the pole tab 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole tab 20. Moreover, by arranging multiple groups of hole groups 30 along the arrangement direction of the pole piece body 10 and the pole tab 20, a larger extension processing area can be reserved for the pole tab 20, further reducing the extension difference between the pole tab 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole tab 20.

[0069] In the above technical solution, by providing multiple hole structures 13, the number of hole structures 13 on the pole piece body 10 can be increased, which is more conducive to reducing the extension of the pole piece body 10, further reducing the extension difference between the pole tab 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole tab 20. In addition, by arranging multiple groups of hole groups 30 along the arrangement direction of the pole piece body 10 and the pole tab 20, a larger extension processing area can be reserved for the pole tab 20, further reducing the extension difference between the pole tab 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole tab 20.

[0070] According to some embodiments of the present application, as shown in FIG9 , along the arrangement direction of the pole piece body 10 and the pole tab 20 , the spacing distance between two adjacent groups of hole groups 30 is greater than 0 mm and less than or equal to 4 mm.

[0071] Among them, along the arrangement direction of the pole piece body 10 and the pole tab 20, the spacing distance between two adjacent groups of hole groups 30 is D2, which satisfies the relationship: 0mm<D2≤4mm. For example, the spacing distance between two adjacent groups of hole groups 30 is 1mm, 2mm, 3mm, 4mm, etc. Since the cold pressing is performed along the tape running direction, the required extension of the pole piece body 10 along the arrangement direction of the pole piece body 10 and the pole tab 20 is relatively small. By setting the spacing distance between two adjacent groups of hole groups 30 to be greater than 0mm and less than or equal to 4mm, the spacing distance between two adjacent groups of hole groups 30 can be made appropriate, and the multiple hole structures 13 can be arranged more compactly, which is more conducive to reducing the extension difference between the pole tab 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole tab 20.

[0072] In the above technical solution, by making the spacing distance between two adjacent groups of hole groups 30 greater than 0 mm and less than or equal to 4 mm, the spacing distance between two adjacent groups of hole groups 30 can be made appropriate, and the positions of multiple hole structures 13 can be set more compactly, which is more conducive to reducing the extension difference between the pole ear 20 and the pole piece body 10, and further reducing the risk of wavy edges and cracking of the pole ear 20.

[0073] According to some embodiments of the present application, as shown in FIG9 , the spacing distance between two adjacent hole structures 13 in each hole group 30 is greater than or equal to 0.5 mm and less than or equal to 10 mm.

[0074] Among them, the spacing distance between two adjacent hole structures 13 in each hole group 30 is D3, which satisfies the relationship 0.5mm≤D3≤10mm. For example, the spacing distance between two adjacent hole structures 13 in each hole group 30 is 0.5mm, 0.6mm, 5mm, 6mm, 10mm, etc. It should be noted that if the spacing distance between two adjacent hole structures 13 in each hole group 30 is less than 0.5mm, it will affect the strength of the pole piece body 10. If the spacing distance between two adjacent hole structures 13 in each hole group 30 is greater than 10mm, it will not play a role in reducing the elongation of the pole piece body 10. Therefore, in the present application, by setting the spacing distance between two adjacent hole structures 13 in each hole group 30 to be greater than or equal to 0.5mm and less than or equal to 10mm, the pole piece body 10 can have sufficient strength, and can also achieve the effect of reducing the elongation of the pole piece body 10, reduce the elongation difference between the pole tab 20 and the pole piece body 10, and effectively reduce the risk of wavy edges and cracking of the pole tab 20.

[0075] In the above technical solution, by setting the spacing distance between two adjacent hole structures 13 in each hole group 30 to be greater than or equal to 0.5 mm and less than or equal to 10 mm, the pole piece body 10 can have sufficient strength, and the effect of reducing the elongation of the pole piece body 10 can be achieved, reducing the elongation difference between the pole ear 20 and the pole piece body 10, and effectively reducing the risk of wavy edges and cracking of the pole ear 20.

[0076] According to some embodiments of the present application, as shown in FIG9 , the pore structure 13 is a circular hole, and the pore diameter of the pore structure 13 is greater than or equal to 0.1 μm and less than or equal to 50 μm.

[0077] Among them, the pore structure 13 is a circular hole, the pore diameter of the pore structure 13 is the diameter of the hole, the pore diameter of the pore structure 13 is Φ, 0.1μm≤Φ≤50μm, for example: the pore diameter of the pore structure 13 is 0.1μm, 0.5μm, 1μm, 10μm, 20μm, 30μm, 50μm and other values. It should be noted that if the pore size of the pore structure 13 is less than 0.1 μm, the pore size of the pore structure 13 will be smaller than the particle size of the active material layer 12, and the particles of the active material layer 12 cannot fall into the pore structure 13, which cannot achieve the effect that the compaction of the area of ​​the pole piece body 10 provided with the pore structure 13 is smaller than the compaction of the area of ​​the pole piece body 10 not provided with the pore structure 13. If the pore size of the pore structure 13 is greater than 50 μm, it is easy to affect the strength of the pole piece body 10, easily cause the pole piece body 10 to crack, and cannot achieve the effect that the compaction of the area of ​​the pole piece body 10 provided with the pore structure 13 is smaller than the compaction of the area of ​​the pole piece body 10 not provided with the pore structure 13. Therefore, in the present application, by making the pore size of the pore structure 13 greater than or equal to 0.1 μm and less than or equal to 50 μm, the compaction of the area of ​​the pole piece body 10 provided with the pore structure 13 can be made smaller than the compaction of the area of ​​the pole piece body 10 not provided with the pore structure 13, and the pole piece body 10 can also have sufficient strength, reducing the risk of cracking of the pole piece body 10.

[0078] In the above technical solution, by making the pore size of the pore structure 13 greater than or equal to 0.1 μm and less than or equal to 50 μm, the compression of the area of ​​the pole piece body 10 where the pore structure 13 is provided can be smaller than the compression of the area of ​​the pole piece body 10 where the pore structure 13 is not provided, and the pole piece body 10 can also have sufficient strength to reduce the risk of cracking of the pole piece body 10.

[0079] According to some embodiments of the present application, the electrode sheet 100 may be a negative electrode sheet 100, and the active material layer 12 may be hard carbon. The active material layer 12 may be made of hard carbon, but the present application is not limited thereto; the active material layer 12 may also be made of soft carbon. This application uses the example of an active material layer 12 made of hard carbon. Hard carbon is hard and has high ductility. By configuring the electrode sheet 100 as a negative electrode sheet 100, the energy density of the battery cell 200 can be increased.

[0080] Secondly, embodiments of the present application further provide a battery cell 200 comprising the pole piece 100 of the aforementioned embodiment. By providing the pole piece body 10 with the hole structure 13, a larger extension processing area is reserved for the tab 20, thereby reducing the extension difference between the tab 20 and the pole piece body 10 and lowering the risk of wavy edges and cracking of the tab 20. This improves the product quality of the battery cell 200 and contributes to increasing the energy density of the battery cell 200.

[0081] According to some embodiments of the present application, the battery cell 200 is a sodium ion battery 300 .

[0082] In the above technical solution, by configuring the battery cell 200 as a sodium ion battery 300 , the product quality of the battery cell 200 can be improved, which is beneficial to improving the energy density of the battery cell 200 .

[0083] As shown in FIG3 , the battery cell 200 may include a housing 201 , a cover 202 , an electrode assembly 203 and an electrolyte. The housing 201 is used to accommodate the electrode assembly 203 and the electrolyte. The cover 202 is provided on an open end of the housing 201 .

[0084] In a third aspect, an embodiment of the present application further provides a battery 300 , comprising the battery cell 200 of the above embodiment.

[0085] Fourthly, an embodiment of the present application further provides an electrical device, comprising the battery 300 of the above embodiment.

[0086] According to some embodiments of the present application, as shown in Figure 5, the present application provides a pole piece 100, which includes: a pole piece body 10 and a pole ear 20, the pole piece body 10 includes a current collector 11 and an active material layer 12, the current collector 11 is connected to the pole ear 20, the active material layer 12 is arranged on the outer surface of the current collector 11, the pole piece body 10 has a hole structure 13 that penetrates the pole piece body 10 along the thickness direction of the pole piece 10, and the hole structure 13 is arranged close to the pole ear 20.

[0087] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0088] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0089] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cell, wherein: include: A pole piece, comprising a pole piece body and a pole ear, wherein the pole piece body comprises a current collector and an active material layer, the current collector is connected to the pole ear, the active material layer is arranged on the outer surface of the current collector, and the pole piece body has a pore structure extending along the thickness direction of the pole piece.

2. The battery cell according to claim 1, wherein: The current collector and / or the active material layer is formed with the pore structure.

3. The battery cell according to claim 1 or 2, wherein: The pole piece body has a hole setting area adjacent to the pole ear, and the hole setting area has the hole structure.

4. The battery cell according to claim 3, wherein: Along the arrangement direction of the pole piece body and the pole lug, the spacing distance between the edge of the hole arrangement area adjacent to the pole lug and the edge away from the pole lug is greater than 0 mm and less than or equal to 20 mm.

5. The battery cell according to claim 4, wherein: The spacing distance between the edge of the hole arrangement area adjacent to the pole lug and the edge away from the pole lug is greater than 0 mm and less than or equal to 10 mm.

6. The battery cell according to any one of claims 1 to 5, wherein: There are multiple hole structures, and the multiple hole structures form at least one hole group. The hole group includes multiple hole structures. The multiple hole structures in each hole group are arranged along the first direction of the pole piece. The first direction, the thickness direction of the pole piece, and the arrangement directions of the pole piece body and the pole ear are perpendicular to each other.

7. The battery cell according to claim 6, wherein: The plurality of hole structures form a plurality of hole groups, and the plurality of hole groups are arranged along the arrangement direction of the pole piece body and the pole ears.

8. The battery cell according to claim 7, wherein: Along the arrangement direction of the pole piece body and the pole lugs, the spacing distance between two adjacent groups of the hole groups is greater than 0 mm and less than or equal to 4 mm.

9. The battery cell according to any one of claims 6 to 8, wherein: The spacing distance between two adjacent hole structures in each hole group is greater than or equal to 0.5 mm and less than or equal to 10 mm.

10. The battery cell according to any one of claims 1 to 9, wherein: The pore structure is a circular pore, and the pore diameter of the pore structure is greater than or equal to 0.1 μm and less than or equal to 50 μm.

11. The battery cell according to any one of claims 1 to 10, wherein: The electrode sheet is a negative electrode sheet, and the active material layer is hard carbon.

12. The battery cell according to any one of claims 1 to 11, wherein: The battery cell is a sodium ion battery.

13. A battery, wherein: The invention comprises a battery cell according to any one of claims 1 to 12.

14. An electrical device, wherein: Comprising a battery according to claim 13.

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