Binding structure, battery cell, battery and electric device

Abstract

The utility model relates to a binding structure, a battery monomer, a battery and an electric device. The binding structure is arranged in the battery monomer, so that the binding structure is used as a part of the internal structure of the battery monomer, and therefore, during formation exhaust, the binding structure extrudes the surface of the electrode assembly under the binding of the inner wall of the shell, the internal pressure of the electrode assembly is increased, and gas generated in the electrode assembly can be discharged. By means of the design, no external clamp or other equipment is needed, and the formation exhaust cost is reduced. Meanwhile, the binding structure applies pressure to the electrode assembly in the battery monomer, so that an internal self-pressurization exhaust mode is realized, the pressure applying and binding effects are better, the exhaust effect is better, and the film forming quality is favorably improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a restraining structure, a battery cell, a battery and an electrical device. Background Art

[0002] Lithium-ion batteries have high energy density and are widely used. After the battery is prepared, the active substances in the battery are activated by charging and discharging for the first time, and a solid electrolyte interphase (SEI) film is formed on the surface of the active layer of the electrode. This process is called battery formation. Gases are generated during the battery formation process, which will affect the quality of the SEI film, and the quality of the SEI film will affect the performance of the battery.

[0003] To this end, the conventional method is to pressurize and exhaust the gas from the battery using a fixture formation method. However, this method not only has high equipment costs, but also has poor exhaust effect, which affects the film quality of the SEI film. Utility Model Content

[0004] Based on this, it is necessary to provide a restraining structure, a battery cell, a battery and an electrical device, which have low formation exhaust cost and good exhaust effect, and are conducive to improving the film formation quality.

[0005] In a first aspect, the present application provides a battery cell, comprising: a shell; an electrode assembly housed in the shell; a restraining structure located in the shell and wrapped around the surface of the electrode assembly, the restraining structure being configured to be extruded and fitted with the surface of the electrode assembly under the constraint of the inner wall of the shell.

[0006] The above-mentioned battery cell has the restraint structure built into the battery cell, so that the restraint structure is a part of the internal structure of the battery cell. In this way, during the formation and exhaust, the restraint structure squeezes the surface of the electrode assembly under the constraint of the inner wall of the shell, increases the internal pressure of the electrode assembly, and helps to exhaust the gas generated inside the electrode assembly. With this design, there is no need to use external clamps and other equipment, which reduces the cost of formation and exhaust. At the same time, this restraint structure applies pressure to the electrode assembly inside the battery cell to achieve an internal self-pressurized exhaust method, which has better pressure and restraint effects, better exhaust effects, and is conducive to improving the film quality.

[0007] In some embodiments, the restraint structure includes two parallel and spaced restraints, between which at least one electrode assembly is accommodated, and each restraint is pressed and matched with the side of the electrode assembly. With such a design, the restraint can effectively clamp the battery cell, so that the formation and exhaust effect is better; at the same time, during the cycle charge and discharge, the restraints on both sides can effectively suppress the gap between the pole pieces in the electrode assembly, reduce the lithium ion transport distance, effectively reduce the probability of pole piece wrinkle lithium deposition and edge lithium deposition, and improve battery life and performance.

[0008] In some embodiments, the electrode assembly is constructed as a cylindrical structure, and each of the restraining members is pressed and matched with the electrode assembly along the circumferential side around its own axis. In this design, by introducing the restraining members, the circumference of the cylindrical electrode assembly is effectively constrained, the exhaust effect during the formation process is improved, and thus the film formation quality is improved.

[0009] In some embodiments, the electrode assembly is constructed as a flat structure, and each restraining member is pressed and matched with a side surface of the electrode assembly along its thickness direction. Such a design effectively restrains the large side of the electrode assembly, effectively restrains the overall expansion of the electrode assembly, and effectively discharges the generated gas; or, inhibits the increase of the gap between the pole pieces in the electrode assembly, and reduces the probability of lithium deposition.

[0010] In some embodiments, the restraining structure further includes a fixing member, which is disposed on at least one restraining member, and one end of the housing along a preset direction has an opening, and the fixing member is at least partially crimped to one end of the electrode assembly facing the opening. With such a design, the introduction of the fixing member not only allows the electrode assembly to be tightly combined with the restraining structure, but also forms a restraining effect on the electrode assembly in the preset direction.

[0011] In some embodiments, the fixing member includes a connecting portion and a crimping portion connected to the connecting portion, the connecting portion is connected to the restraining member, and the crimping portion protrudes on one side of the connecting portion toward the electrode assembly, and is used to be crimped on one end of the electrode assembly. Such a design facilitates the crimping of the fixing member on one end of the electrode assembly, making the combination of the electrode assembly and the restraining structure more stable, improving the restraining effect on the electrode assembly, and thus improving the reliability of the battery.

[0012] In some embodiments, on the restraining member connected to the fixing member, the fixing member includes multiple fixing members, all of which are sequentially distributed along a direction intersecting with the preset direction, and are all used to be crimped to one end of the electrode assembly. In this design, multiple fixing members are introduced to increase the crimping points between the electrode assembly and the restraining structure, further improving the restraining effect on the electrode assembly.

[0013] In some embodiments, the fixing member is configured to rotate or deform relative to the restraining member, and an edge of the shell surrounding the opening is configured to drive the fixing member to be crimped to one end of the electrode assembly. With this design, during the shell insertion process, the fixing member is automatically crimped to one end of the electrode assembly under the driving action of one edge of the shell, thereby improving assembly efficiency.

[0014] In some embodiments, the size of the restraining member in the preset direction is greater than the size of the fixing member in the preset direction. With such a design, increasing the size ratio of the restraining member in the preset direction can increase the restraining area between the restraining member and the electrode assembly, improve the restraining effect, and thus improve the formation exhaust effect.

[0015] In some embodiments, the size of the restraining member in the preset direction is recorded as L1, and the size of the fixing member in the preset direction is recorded as L2, wherein 8≤L1 / L2≤15. With such a design, the ratio of the size of the restraining member in the preset direction to the size of the fixing member in the preset direction is controlled between 8 and 15, effectively taking into account the restraining effect and fixing effect of the restraining structure on the electrode assembly.

[0016] In some embodiments, the condition satisfied by dimension L1 is: 80mm≤L1≤210mm; by such a design, dimension L1 is controlled between 80mm and 210mm, so that there is a reasonable extrusion area between the restraint and the electrode assembly, thereby improving the restraint effect on the electrode assembly and enhancing the formation exhaust effect; at the same time, the risk of lithium plating is also reduced.

[0017] Optionally, the dimension L1 also satisfies the condition: 100 mm ≤ L1 ≤ 170 mm.

[0018] In some embodiments, the restraint structure further includes a base, on which two restraint members are spaced apart, and the base is used to support the electrode assembly. With such a design, the base is introduced so that the electrode assembly is stabilized between the two restraint members, achieving an effective restraint effect and improving the formation exhaust effect.

[0019] In some embodiments, the base is provided with a plurality of through holes. In this design, the base is provided with through holes so that the electrolyte can penetrate the electrode assembly through the through holes, so that the battery cell can work stably.

[0020] In some embodiments, the battery cell further includes an elastic member, which is disposed in the housing and abuts against a side of the base facing away from the electrode assembly. With such a design, the introduction of the elastic member allows the electrode assembly and the restraining structure to be smoothly loaded into the housing, reducing the risk of the electrode assembly hitting the inner wall of the housing during assembly and improving the assembly quality; at the same time, the elastic member also facilitates close contact between the restraining structure and the electrode assembly.

[0021] In some embodiments, the battery cell further includes a tensioning member, which is disposed on the surface of the electrode assembly and abuts against the restraining structure. With such a design, the tensioning member is introduced so that the restraining structure is tightly wrapped around the surface of the electrode assembly, so that the restraining force on the restraining structure is effectively transmitted to the electrode assembly, thereby achieving a better restraining effect.

[0022] In some embodiments, the expansion piece is configured as a structure capable of volume expansion. In this way, the expansion piece is configured as a structure capable of volume expansion, so that the expansion piece fills the space between the electrode assembly and the restraining structure during formation of the battery cell, so that the extrusion force between the electrode assembly and the restraining structure is stably transmitted, thereby further improving the formation exhaust effect.

[0023] In a second aspect, the present application provides a battery, the battery comprising any of the above battery cells.

[0024] In a third aspect, the present application provides an electrical device, which includes the above battery.

[0025] In a fourth aspect, the present application provides a restraining structure, which includes a base, a fixing part and two restraining parts. The two restraining parts are arranged on the base at intervals, and are used to accommodate at least one electrode assembly. The fixing part is arranged at one end of at least one restraining part away from the base, and the fixing part is at least partially used to be crimped on the end of the electrode assembly having a pole ear.

[0026] With this design, the restraints can effectively clamp the battery cells, resulting in better formation and exhaust effects. At the same time, during cyclic charge and discharge, the restraints on both sides can effectively suppress the gaps between the pole pieces in the electrode assembly, reduce the lithium ion transport distance, effectively reduce the occurrence rate of pole piece wrinkling and edge lithium deposition, and improve battery life and performance.

[0027] In some embodiments, the base is provided with a plurality of through holes. In this design, the base is provided with through holes so that the electrolyte can penetrate the electrode assembly through the through holes, so that the battery cell can work stably.

[0028] In some embodiments, the fixing member includes a connecting portion and a crimping portion connected to the connecting portion, the connecting portion is connected to the restraining member, and the crimping portion protrudes on one side of the connecting portion toward the electrode assembly, and is used to be crimped on one end of the electrode assembly. Such a design facilitates the crimping of the fixing member on one end of the electrode assembly, making the combination of the electrode assembly and the restraining structure more stable, improving the restraining effect on the electrode assembly, and thus improving the reliability of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application.

[0030] Figure 2An exploded view of a battery provided for some embodiments of the present application.

[0031] Figure 3 A schematic diagram of the exploded structure of a battery cell provided in some embodiments of the present application.

[0032] Figure 4 This is a schematic diagram of the structure of the electrode assembly before being put into the shell provided in some embodiments of the present application.

[0033] Figure 5 A schematic diagram of the structure of the electrode assembly when it is put into the shell provided in some embodiments of the present application.

[0034] Figure 6 Schematic diagram of the binding structure provided for some embodiments of the present application.

[0035] Figure 7 A schematic diagram of the structure of a cylindrical electrode assembly and a restraining structure provided in some embodiments of the present application.

[0036] Figure 8 A schematic diagram of the structure of a flat electrode assembly after being put into a shell provided in some embodiments of the present application.

[0037] Fig. 9 A schematic diagram of the structure of a fixing member provided in some embodiments of the present application.

[0038] Fig.10 A schematic diagram of the structure of the binding member and the base provided in some embodiments of the present application.

[0039] 1000, vehicle; 100, battery; 200, controller; 300, motor; 10, battery cell; 20, housing; 201, first part; 202, second part; 1, housing; 11, opening; 12, edge; 2, electrode assembly; 21, pole ear; 22, large surface; 23, circumferential side; 3, restraining structure; 31, restraining member; 311, notch; 32, fixing member; 321, connecting part; 322, crimping part; 323, slot; 324, rotating shaft; 33, base; 331, through hole; 4, expansion member; 5, elastic member; 6, end cap; 61, electrode terminal; X, preset direction; Y, thickness direction; Z, spacing direction; S, distribution direction. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0041] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0042] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0043] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0044] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0045] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If present, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0046] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0047] After the battery is prepared, the first charge and discharge method is used to activate the active substances in the battery and form a solid electrolyte interphase (SEI) film on the surface of the active layer of the electrode. This process is called battery formation. During the battery formation process, gases are generated, which will affect the quality of the SEI film, and the quality of the SEI film will affect the performance of the battery.

[0048] Generally, the traditional formation exhaust method is to encapsulate the electrode assembly and electrolyte in an aluminum shell, and then use a clamping device to clamp and press the surface of the aluminum shell to suppress the gap between the pole pieces in the electrode assembly so that the gas can be discharged. However, this method requires additional clamping equipment, which is costly. At the same time, this exhaust method is to apply pressure to the outside of the aluminum shell, and the pressure effect on the electrode assembly is poor, resulting in poor exhaust effect, resulting in poor film quality and formation effect of the SEI film.

[0049] Based on this, in order to solve the problem of high cost and poor exhaust effect of traditional formation exhaust, the present application provides a battery cell. The restraint structure is built into the battery cell, so that the restraint structure is part of the internal structure of the battery cell. In this way, during the formation exhaust, the restraint structure squeezes the surface of the electrode assembly under the constraint of the inner wall of the shell, increases the internal pressure of the electrode assembly, and helps to discharge the gas generated inside the electrode assembly. With this design, there is no need to use external equipment such as clamps, which reduces the cost of formation exhaust. At the same time, the restraint structure applies pressure to the electrode assembly inside the battery cell to achieve an internal self-pressurized exhaust method, which has better pressure and constraint effects, better exhaust effect, and is conducive to improving the film quality.

[0050] In addition, since the built-in restraint structure is part of the internal structure of the battery cell, the electrode assembly can be always restrained by the restraint structure when the battery is charging and discharging, which is beneficial to reducing the lithium ion transport distance between the pole pieces in the electrode assembly, and can effectively reduce the occurrence of pole piece wrinkling and edge lithium deposition, thereby improving battery life and performance.

[0051] The battery cells disclosed in the embodiments of the present application can be used, but not limited to, in electrical devices such as vehicles, ships or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical device.

[0052] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, 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., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0053] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0054] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0055] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0056] Please refer to Figure 2 , Figure 2An exploded view of a battery 100 provided for some embodiments of the present application. The battery 100 includes a box body 20 and a battery cell 10, and the battery cell 10 is contained in the box body 20. Among them, the box body 20 is used to provide a storage space for the battery cell 10, and the box body 20 can adopt a variety of structures. In some embodiments, the box body 20 may include a first part 201 and a second part 202, and the first part 201 and the second part 202 cover each other, and the first part 201 and the second part 202 jointly define a storage space for accommodating the battery cell 10. The second part 202 may be a hollow structure with an opening 11 at one end, and the first part 201 may be a plate-like structure, and the first part 201 covers the open side of the second part 202, so that the first part 201 and the second part 202 jointly define a storage space; the first part 201 and the second part 202 may also be hollow structures with an opening 11 on one side, and the open side of the first part 201 covers the open side of the second part 202. Of course, the box body 20 formed by the first part 201 and the second part 202 can be in various shapes, such as a cylinder, a cuboid, etc.

[0057] In the battery 100, there may be multiple battery cells 10, and the multiple battery cells 10 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 10 are both connected in series and in parallel. The multiple battery cells 10 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 10 is accommodated in the box 20; of course, the battery 100 may also be a battery 100 module formed by connecting multiple battery cells 10 in series, in parallel, or in a mixed connection, and then the multiple battery 100 modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 20. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 10.

[0058] Each battery cell 10 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 may be cylindrical, flat, rectangular, or in other shapes.

[0059] Please refer to Figure 3 , Figure 3 The schematic diagram of the exploded structure of the battery cell 10 provided in some embodiments of the present application. The battery cell 10 refers to the smallest unit constituting the battery 100. Figure 3 The battery cell 10 includes an end cover 6, a shell 1, an electrode assembly 2 and other functional components.

[0060] The end cap 6 refers to a component that covers the opening 11 of the shell 1 to isolate the internal environment of the battery cell 10 from the external environment. Without limitation, the shape of the end cap 6 can be adapted to the shape of the shell 1 to match the shell 1. Optionally, the end cap 6 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 6 is not easily deformed when squeezed and collided, so that the battery cell 10 can have a higher structural strength and reliability can also be improved. Functional components such as electrode terminals 61 can be provided on the end cap 6. The electrode terminal 61 can be used to electrically connect to the electrode assembly 2 for outputting or inputting electrical energy of the battery cell 10. In some embodiments, the end cap 6 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The material of the end cap 6 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 6, and the insulating member may be used to isolate the electrical connection part 321 in the housing 1 from the end cap 6 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0061] The shell 1 is a component used to cooperate with the end cap 6 to form the internal environment of the battery cell 10, wherein the formed internal environment can be used to accommodate the electrode assembly 2, the electrolyte and other components. The shell 1 and the end cap 6 can be independent components, and an opening 11 can be set on the shell 1, and the internal environment of the battery cell 10 is formed by covering the opening 11 with the end cap 6 at the opening 11. Without limitation, the end cap 6 and the shell 1 can also be integrated. Specifically, the end cap 6 and the shell 1 can form a common connection surface before other components are put into the shell, and when the interior of the shell 1 needs to be encapsulated, the end cap 6 is covered with the shell 1. The shell 1 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 1 can be determined according to the specific shape and size of the electrode assembly 2. The material of the shell 1 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0062] The electrode assembly 2 is a component in the battery cell 10 where electrochemical reactions occur. One or more electrode assemblies 2 may be included in the housing 1. The electrode assembly 2 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 2, and the parts of the positive and negative electrode sheets without active materials each constitute a tab 21. The positive tab 21 and the negative tab 21 may be located together at one end of the main body or at both ends of the main body respectively. During the charge and discharge process of the battery 100, the positive active material and the negative active material react with the electrolyte, and the tab 21 connects the electrode terminal 61 to form a current loop.

[0063] According to some embodiments of this application, please refer to Figure 4 and Figure 5 The present application provides a battery cell 10, which includes: a shell 1, an electrode assembly 2, and a restraining structure 3. The electrode assembly 2 is accommodated in the shell 1, and the restraining structure 3 is located in the shell 1 and wrapped around the surface of the electrode assembly 2. The restraining structure 3 is configured to be pressed and matched with the surface of the electrode assembly 2 under the constraint of the inner wall of the shell 1.

[0064] The electrode assembly 2 refers to the part in the battery cell 10 where the electrochemical reaction occurs, and it can be a laminated structure or a wound structure. When the electrode assembly 2 is a wound structure, its shape can be, but is not limited to, flat, cylindrical, etc. If the shape of the electrode assembly 2 is cylindrical, the shape of the housing 1 can also be designed to be cylindrical accordingly, and at the same time, the surface of the restraining structure 3 that contacts the electrode assembly 2 can also be designed to be a cylindrical curved surface.

[0065] The restraining structure 3 is wrapped on the surface of the electrode assembly 2 and is installed in the shell 1 together with the electrode assembly 2. In this way, during the formation, the restraining structure 3 is constrained by the inner wall of the shell 1 to squeeze the electrode assembly 2, increase the pressure inside the electrode assembly 2, and accelerate the discharge of the gas generated by the formation.

[0066] At the same time, in normal cycle charge and discharge, the binding structure 3 is built into the shell 1, which can suppress the gap between the pole pieces inside the electrode assembly 2, shorten the lithium ion transmission path, and effectively reduce the probability of lithium deposition on the pole piece wrinkles and edges 12, thereby improving the life and reliability of the battery 100. In addition, adding the binding structure 3 to the outside of the bare electrode assembly 2 can protect the electrode assembly 2, eliminate the bottom support sheet at the bottom of the electrode assembly 2 and the outer Mylar film (Mylar film, a type of polyester film), and increase the reliability of the battery 100.

[0067] In addition, the restraining structure 3 is constrained by the inner wall of the shell 1 to squeeze and fit the electrode assembly 2. The implementation method can be directly extruded on the surface of the electrode assembly 2; it can also be indirectly extruded on the surface of the electrode assembly 2, for example: an intermediate structure is set between the electrode assembly 2 and the restraining structure 3, and the restraining structure 3 applies pressure to the electrode assembly 2 through the intermediate structure.

[0068] In order to realize that the restraint structure 3 squeezes the electrode assembly 2 under the constraint of the inner wall of the shell 1, the restraint structure 3 should be made of a material with a certain hardness and resistance to electrolyte, such as but not limited to PP (polypropylene), PVC (Polyvinyl chloride), PMMA (Polymethyl Methacrylate), etc. At the same time, in some examples, when the electrode assembly 2 and the restraint structure 3 are installed in the shell 1 together, the side of the restraint structure 3 facing away from the electrode assembly 2 can be in contact with the inner wall of the shell 1, so that there is a certain pre-pressure between the restraint structure 3 and the electrode assembly 2.

[0069] Such a design eliminates the need for external fixtures and other equipment, thus reducing the formation exhaust cost. At the same time, the restraint structure 3 applies pressure to the electrode assembly 2 inside the battery cell 10 to achieve an internal self-pressurized exhaust method, which has better pressure and restraint effects, better exhaust effects, and is conducive to improving the film formation quality.

[0070] According to some embodiments of the present application, optionally, please refer to Figure 4 and Figure 6 The restraining structure 3 includes two restraining members 31 arranged in parallel and spaced apart from each other. The two restraining members 31 are used to accommodate at least one electrode assembly 2 , and each restraining member 31 is pressed and matched with the side surface of the electrode assembly 2 .

[0071] The restraint 31 refers to a structure that squeezes and fits the side of the electrode assembly 2 under the constraint of the inner wall of the shell 1, so that the inside of the electrode assembly 2 is pressurized and the gas generated during the formation process is discharged. In order to make the restraint 31 exert a certain pressure on the electrode assembly 2, it can be designed to be a hard and electrolyte-resistant structure. For example, the material of the restraint 31 can be but not limited to PP (polypropylene), PVC (Polyvinyl chloride), PMMA (PolymethylMethacrylate), etc.

[0072] The surface of the electrode assembly 2 may include a side surface, a top surface, and a bottom surface. Taking a cylindrical battery 100 as an example, the side surface of the electrode assembly 2 is the circumferential side surface of the electrode assembly 2 around its own axis, and the top surface and the bottom surface of the electrode assembly 2 are respectively the two end surfaces of the electrode assembly 2 along the direction of its own axis. Taking a flat battery 100 as an example, the side surface of the electrode assembly 2 is a side surface of the electrode assembly 2 along its own thickness direction Y, and the top surface and the bottom surface of the electrode assembly 2 are respectively the two end surfaces of the electrode assembly 2 along the direction of its own winding axis.

[0073] Depending on the shape of the electrode assembly 2, the side of the restraint 31 facing the electrode assembly 2 may also be different. For example, when the electrode assembly 2 is cylindrical, the side of the restraint 31 may be a cylindrical surface; when the electrode assembly 2 is a flat structure, the side of the restraint 31 may be a flat surface.

[0074] In addition, one battery cell 10 can be accommodated between the two restraining members 31, or multiple battery cells 10 can be accommodated. Figure 4 The two battery cells 10 are arranged in affixed relation along their thickness direction Y, and restraining members 31 are attached to two side surfaces of the two battery cells 10 that are opposite to each other.

[0075] With such a design, the restraining members 31 can effectively clamp the battery cell 10, so that the formation and exhaust effect is better; at the same time, during the cyclic charge and discharge, the restraining members 31 on both sides can effectively suppress the gap between the pole pieces in the electrode assembly 2, reduce the lithium ion transport distance, and effectively reduce the probability of lithium deposition on the pole piece wrinkles and lithium deposition on the edge 12, thereby improving the life and performance of the battery 100.

[0076] According to some embodiments of the present application, optionally, please refer to Figure 7 The electrode assembly 2 is constructed as a cylindrical structure, and each restraining member 31 is pressed and matched with the electrode assembly 2 along the circumferential side surface 23 around its own axis.

[0077] In order to better extrude the restraining member 31 and the circumferential side surface 23 of the electrode assembly 2 , the side surface of the restraining member 31 facing the electrode assembly 2 may be designed as a cylindrical surface so that the restraining member 31 fits the circumferential side surface 23 .

[0078] With such a design, by introducing the restraining member 31, the cylindrical electrode assembly 2 is effectively constrained in the circumferential direction, thereby improving the exhaust effect during the formation process and thus improving the film formation quality.

[0079] According to some embodiments of the present application, optionally, please refer to Figure 4 The electrode assembly 2 is constructed as a flat structure, and each restraining member 31 is pressed and matched with a side surface of the electrode assembly 2 along its own thickness direction Y.

[0080] The electrode assembly 2 can be formed into a flat structure by lamination or winding. A flat structure refers to a structure whose thickness dimension is much smaller than the length or width dimension of one side along its own thickness direction Y. Usually, both sides of the electrode assembly 2 along its own thickness direction Y are large surfaces 22, that is, the area of ​​the side is larger than the area of ​​the other side surfaces.

[0081] When the electrode assembly 2 is constructed as a flat structure, the large surface 22 of the electrode assembly 2 is subjected to a large expansion force during the formation or cyclic charge and discharge process. Therefore, the restraining member 31 is squeezed and matched with the large surface 22 of the electrode assembly 2, which can effectively restrain the overall expansion of the electrode assembly 2 and effectively discharge the generated gas; or, inhibit the increase of the gap between the pole pieces in the electrode assembly 2 to reduce the probability of lithium plating.

[0082] Such a design effectively constrains the large surface 22 of the electrode assembly 2, thereby effectively restraining the overall expansion of the electrode assembly 2 and effectively discharging the generated gas; or, inhibits the increase of the gap between the pole pieces in the electrode assembly 2 and reduces the probability of lithium deposition.

[0083] According to some embodiments of the present application, optionally, please refer to Figure 5 The restraining structure 3 further includes a fixing member 32, which is disposed on at least one restraining member 31. The housing 1 has an opening 11 at one end along the preset direction X, and the fixing member 32 is at least partially crimped to one end of the electrode assembly 2 facing the opening 11.

[0084] The opening 11 is a structure for the electrode assembly 2 to be installed in the housing 1. When the battery cell 10 is assembled, the end cap 6 can be placed at the opening 11 to maintain a closed environment in the housing 1. The electrode assembly 2 usually has a tab 21 on one end facing the opening 11, so that the tab 21 is easily electrically connected to the electrode terminal 61 of the end cap 6 covering the opening 11.

[0085] The fixing part 32 refers to a structure crimped on one end of the electrode assembly 2. When the restraining part 31 abuts between the electrode assembly 2 and the inner wall of the shell 1, the fixing part 32 is pressed on one end of the electrode assembly 2 along the preset direction X. This not only makes the electrode assembly 2 and the restraining structure 3 tightly combined; but also forms a restraining effect on the electrode assembly 2 in the preset direction X.

[0086] It should also be noted that the fixing member 32 can be provided on one of the binding members 31; or it can be provided on two binding members 31. When both binding members 31 have fixing members 32, the fixing members 32 on the two binding members 31 are crimped onto the same end of the electrode assembly 2. For details, please refer to Figure 6 .

[0087] With such a design, the fixing member 32 is introduced, which not only makes the electrode assembly 2 and the restraining structure 3 tightly combined, but also forms a restraining effect on the electrode assembly 2 in the preset direction X.

[0088] According to some embodiments of the present application, optionally, please refer to Figure 5 and Fig. 9The fixing member 32 includes a connecting portion 321 and a crimping portion 322 connected to the connecting portion 321 . The connecting portion 321 is connected to the restraining member 31 . The crimping portion 322 protrudes on one side of the connecting portion 321 toward the electrode assembly 2 and is used to be crimped on one end of the electrode assembly 2 .

[0089] The connecting portion 321 refers to the portion of the fixing member 32 that is connected to the restraining member 31, and the crimping portion 322 refers to the structure of the fixing member 32 that is crimped to the electrode assembly 2. The crimping portion 322 protrudes on the connecting portion 321 toward one side of the electrode assembly 2, so that a slot 323 can be formed between the crimping portion 322 and the connecting portion 321, and the shape of the slot 323 can be roughly L-shaped. When the restraining member 31 is squeezed between the electrode assembly 2 and the inner wall of the shell 1, the slot 323 is clamped on one end of the electrode assembly 2.

[0090] The connecting portion 321 and the crimping portion 322 may be an integrated structure or a combined structure, for example, they may be combined and connected by bolt connection, clamping, riveting, welding, etc.

[0091] Such a design facilitates the fixing member 32 to be crimped onto one end of the electrode assembly 2 , making the combination of the electrode assembly 2 and the restraining structure 3 more stable, thereby improving the restraining effect on the electrode assembly 2 and thus improving the reliability of the battery 100 .

[0092] According to some embodiments of the present application, optionally, please refer to Figure 6 On the restraining member 31 connected with the fixing member 32, the fixing member 32 includes a plurality of fixing members 32, all of which are distributed in sequence along a direction intersecting with the preset direction X, and are all used for crimping on one end of the electrode assembly 2.

[0093] It is easy to understand that all the fixing members 32 can be crimped onto one end of the electrode assembly 2, which means that the distribution direction S of the fixing members 32 not only intersects with the preset direction X, but also intersects with the spacing direction Z between the restraining members 31. In some examples, the distribution direction S of the fixing members 32, the spacing direction Z between the restraining members 31, and the preset direction X are perpendicular to each other.

[0094] The number of the fixing members 32 on the same binding member 31 may not be limited to Figure 6 The three shown in the figure may be other numbers, such as two, four, five or more. When both of the two binding members 31 have fixing members 32, the number of fixing members 32 on the two binding members 31 may be the same or different. At the same time, the fixing members 32 on the two binding members 31 may be arranged opposite to each other in the spacing direction Z, or may be staggered.

[0095] With such a design, multiple fixing members 32 are introduced to increase the crimping points between the electrode assembly 2 and the restraining structure 3 , thereby further improving the restraining effect on the electrode assembly 2 .

[0096] According to some embodiments of the present application, optionally, please refer to Figure 8 The fixing member 32 is constructed to be rotatable or deformable relative to the restraining member 31 , and an edge 12 of the shell 1 surrounding the opening 11 is configured to drive the fixing member 32 to be pressed against one end of the electrode assembly 2 .

[0097] During the assembly process of the battery cell 10, the restraining structure 3 coated on the surface of the electrode assembly 2 is loaded into the housing 1 from the opening 11 together with the electrode assembly 2. At this time, the fixing member 32 is in an open state and is not crimped on one end of the electrode assembly 2. As the loading continues, an edge 12 of the housing 1 around the opening 11 contacts the fixing member 32 and drives the fixing member 32 to rotate or deform toward one side of the electrode assembly 2, so that the fixing member 32 is automatically crimped on one end of the electrode assembly 2.

[0098] The fixing member 32 can be rotatably connected to the binding member 31, such as by hinge, shaft hole matching, etc.; or, the fixing member 32 and the binding member 31 are an integrated structure, and there is a bendable fold between the fixing member 32 and the binding member 31. For specific embodiments, please refer to Fig. 9 and Fig.10 The fixing member 32 includes a connecting portion 321 and a crimping portion 322 . A notch 311 is provided at one end of the restraining member 31 . The connecting portion 321 is rotatably connected to the inner wall of the notch 311 through a rotating shaft 324 .

[0099] In addition, when the fixing member 32 is erected and crimped onto one end of the electrode assembly 2 under the action of an edge 12 on the shell 1, the side of the fixing member 32 facing away from the electrode assembly 2 can be flush with the side of the restraining member 31 facing away from the electrode assembly 2. In this way, while achieving effective restraint, the space along the thickness direction Y of the electrode assembly 2 will not be increased, thereby improving the space utilization rate within the battery cell 10.

[0100] Of course, in other embodiments, the side surface of the fixing member 32 facing away from the electrode assembly 2 may not exceed or exceed the side surface of the restraining member 31 facing away from the electrode assembly 2 .

[0101] With such a design, during the shell insertion process, the fixing member 32 is automatically pressed onto one end of the electrode assembly 2 by the driving action of an edge 12 of the shell 1, thereby improving the assembly efficiency.

[0102] According to some embodiments of the present application, optionally, the size of the restraining member 31 in the preset direction X is greater than the size of the fixing member 32 in the preset direction X.

[0103] The size of the restraining member 31 in the preset direction X is larger than the size of the fixing member 32 in the preset direction X, which means that the restraining member 31 can contact more parts of the electrode assembly 2 in the preset direction X. Since the fixing member 32 is crimped on the end of the electrode assembly 2 facing the opening 11, it plays the role of restraining one end of the electrode assembly 2 and fixing the restraining member 31. Therefore, the size of the fixing member 32 in the preset direction X should be designed to be smaller, and the size of the restraining member 31 in the preset direction X should be increased.

[0104] When the restraining member 31 abuts against a side surface of the electrode assembly 2 along its own thickness direction Y, the area where the restraining member 31 and the electrode assembly 2 are attached can occupy more than half of the area of ​​the side surface of the electrode assembly 2 along its own thickness direction Y.

[0105] With such a design, the size proportion of the restraining member 31 in the preset direction X is increased, and the restraining area between the restraining member 31 and the electrode assembly 2 can be increased, thereby improving the restraining effect and thus improving the formation exhaust effect.

[0106] According to some embodiments of the present application, optionally, please refer to Fig. 9 and Fig.10 The dimension of the restraining member 31 in the preset direction X is recorded as L1, and the dimension of the fixing member 32 in the preset direction X is recorded as L2, wherein 8≤L1 / L2≤15.

[0107] The value of L1 / L2 can affect the binding effect of the binding structure 3 on the electrode assembly 2, and also affect the connection between the binding structure 3 and the electrode assembly 2. When the value of L1 / L2 is too small, it means that the compression area between the binding member 31 and the electrode assembly 2 is small, and the binding effect is poor; when the value of L1 / L2 is too large, it means that the size of the fixing member 32 is small, and the force of pressing on the electrode assembly 2 is relatively weak.

[0108] To this end, the ratio of L1 / L2 can be between 8 and 15, for example: L1 / L2 can be but not limited to 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0109] With such a design, the ratio of the size of the restraining member 31 in the preset direction X to the size of the fixing member 32 in the preset direction X is controlled between 8 and 15, effectively taking into account both the restraining effect and the fixing effect of the restraining structure 3 on the electrode assembly 2 .

[0110] According to some embodiments of the present application, optionally, the dimension L1 satisfies the condition: 80 mm ≤ L1 ≤ 210 mm.

[0111] The size of the dimension L1 can directly affect the extrusion area between the restraining member 31 and the electrode assembly 2, thereby affecting the restraining effect on the electrode assembly 2. The dimension L1 can be between 80 mm and 210 mm, for example, but not limited to 80 mm, 90 mm, 100 mm, 120 mm, 140 mm, 160 mm, 180 mm, 200 mm, 210 mm, etc. Of course, in some other embodiments, the dimension L1 can also be between 100 mm and 170 mm, for example, but not limited to 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, etc.

[0112] It should also be noted that, in order to better squeeze the electrode assembly 2 , the width of the restraining member 31 may be equal to or greater than the width of the electrode assembly 2 .

[0113] With such a design, the dimension L1 is controlled between 80 mm and 210 mm, so that there is a reasonable extrusion area between the restraining member 31 and the electrode assembly 2, thereby improving the restraining effect on the electrode assembly 2 and enhancing the formation exhaust effect; at the same time, it also reduces the risk of lithium plating.

[0114] According to some embodiments of the present application, optionally, please refer to Figure 6 The restraining structure 3 also includes a base 33 , and two restraining members 31 are spaced apart on the base 33 . The base 33 is used to support the electrode assembly 2 .

[0115] The base 33 refers to a structure that supports the electrode assembly 2 between the two restraining members 31. The restraining members 31 can be fixed on the base 33 or can be movable relative to the base 33. When the restraining members 31 are fixed on the base 33, a space matching the size of the electrode assembly 2 can be formed between the two restraining members 31 and the base 33; when the restraining members 31 are movable relative to the base 33, for example: there is a bendable fold between the restraining members 31 and the base 33; or, the restraining members 31 and the base 33 are rotatably connected.

[0116] When the restraining structure 3 further includes a fixing member 32, the fixing member 32 is disposed at an end of the restraining member 31 away from the base 33. When the electrode assembly 2 is supported on the base 33, the fixing member 32 is pressed against an end of the electrode assembly 2 facing away from the base 33. At this time, the fixing member 32 and the base 33 cooperate with each other, so that the electrode assembly 2 is stably confined between the fixing member 32 and the base 33, thereby stably combining the electrode assembly 2 with the restraining structure 3; at the same time, it is also beneficial to improve the restraining effect on the electrode assembly 2.

[0117] Optionally, the restraining member 31 and the base 33 may be an integrated structure or a combined structure. For example, the two may be connected by, but not limited to, bonding, snap-fitting, dovetail joints, and the like.

[0118] With such a design, the base 33 is introduced, so that the electrode assembly 2 is stabilized between the two restraining members 31, achieving an effective restraining effect and improving the formation exhaust effect.

[0119] According to some embodiments of the present application, optionally, please refer to Figure 6 A plurality of through holes 331 are formed through the base 33 .

[0120] The base 33 is provided with through holes 331, which allow the electrolyte outside the binding structure 3 to flow to the electrode assembly 2 through the through holes 331 and infiltrate the inside of the electrode assembly 2. The through holes 331 can be distributed in various ways on the base 33, such as: matrix arrangement, circular arrangement; or irregular close arrangement.

[0121] With such a design, a through hole 331 is introduced on the base 33 , so that the electrolyte can penetrate the electrode assembly 2 through the through hole 331 , so that the battery cell 10 can work stably.

[0122] According to some embodiments of the present application, optionally, please refer to Figure 4 The battery cell 10 further includes an elastic member 5 , which is disposed in the housing 1 and abuts against a side surface of the base 33 facing away from the electrode assembly 2 .

[0123] The elastic part 5 refers to a structure that can have an elastic buffering function for the electrode assembly 2 and the restraining structure 3. For example, when the restraining structure 3 and the electrode assembly 2 are loaded into the shell 1 together, the base 33 contacts the elastic part 5; with the self-gravity of the electrode assembly 2 and the restraining structure 3 or the external thrust, the base 33 will push the elastic part 5, causing it to undergo compression deformation, thereby allowing the electrode assembly 2 and the restraining structure 3 to be smoothly loaded into the shell 1.

[0124] Optionally, the elastic member 5 may be, but is not limited to, a spring, elastic rubber, etc. The number of the elastic member 5 may be one or more. When the number of the elastic member 5 is more than one, all the elastic members 5 abut against a side of the base 33 facing away from the electrode assembly 2 .

[0125] With such a design, the elastic member 5 is introduced, so that the electrode assembly 2 and the restraining structure 3 can be smoothly installed in the shell 1, reducing the risk of the electrode assembly 2 hitting the inner wall of the shell 1 during assembly, thereby improving the assembly quality; at the same time, the elastic member 5 is also conducive to the close contact between the restraining structure 3 and the electrode assembly 2.

[0126] According to some embodiments of the present application, optionally, please refer to Figure 5 The battery cell 10 further includes a tightening member 4 , which is disposed on the surface of the electrode assembly 2 and abuts against the restraining structure 3 .

[0127] The expansion member 4 is a structure squeezed between the electrode assembly 2 and the restraining structure 3, which facilitates the transmission of the restraining force of the restraining structure 3 to the electrode assembly 2. During the assembly of the battery cell 10, the expansion member 4 may or may not expand in volume.

[0128] When the expansion piece 4 cannot expand in volume, the electrode assembly 2 needs to be squeezed by the restraining structure 3 during the assembly process, so that the expansion piece 4 is squeezed between the restraining structure 3 and the electrode assembly 2, so that it is subjected to a certain pre-pressure. When the expansion piece 4 can expand in volume, the volume of the expansion piece 4 increases between the restraining structure 3 and the electrode assembly 2, so that the expansion piece 4 is tightly abutted between the restraining structure 3 and the electrode assembly 2.

[0129] With such a design, the expansion member 4 is introduced, so that the restraining structure 3 is tightly wrapped around the surface of the electrode assembly 2, so that the restraining force on the restraining structure 3 is effectively transferred to the electrode assembly 2, so as to achieve a better restraining effect.

[0130] According to some embodiments of the present application, optionally, the expansion member 4 is constructed as a structure capable of volume expansion.

[0131] There are many choices for the material of the expansion member 4, such as but not limited to expansion tape, foam, synthetic resin, etc.; materials that expand in volume after being heated or in contact with electrolyte can also be selected. Of course, when selecting a reasonable material, the material of the expansion member 4 should be resistant to high temperature and electrolyte.

[0132] In this design, the expansion piece 4 is designed as a volume expandable structure, so that the expansion piece 4 fills the space between the electrode assembly 2 and the restraining structure 3 during formation of the battery cell 10, so that the squeezing force between the electrode assembly 2 and the restraining structure 3 is stably transmitted, thereby further improving the formation exhaust effect.

[0133] According to some embodiments of the present application, the present application provides a battery 100 , and the battery 100 includes any one of the above battery cells 10 .

[0134] According to some embodiments of the present application, the present application provides an electrical device, which includes the above battery 100.

[0135] According to some embodiments of this application, please refer to Figure 6 The present application provides a restraining structure 3, which includes a base 33, a fixing member 32 and two restraining members 31. The two restraining members 31 are arranged on the base 33 at intervals, and are used to accommodate at least one electrode assembly 2. The fixing member 32 is arranged at one end of at least one restraining member 31 away from the base 33, and at least part of the fixing member 32 is used to be crimped on one end of the electrode assembly 2 having the pole ear 21.

[0136] The restraining structure 3 is wrapped on the surface of the electrode assembly 2 and is installed in the shell 1 together with the electrode assembly 2. In this way, during the formation, the restraining structure 3 is constrained by the inner wall of the shell 1 to squeeze the electrode assembly 2, increase the pressure inside the electrode assembly 2, and accelerate the discharge of the gas generated by the formation.

[0137] At the same time, in normal cycle charge and discharge, the binding structure 3 is built into the shell 1, which can suppress the gap between the pole pieces inside the electrode assembly 2, shorten the lithium ion transmission path, and effectively reduce the probability of lithium deposition from pole piece wrinkles and edges 12, thereby improving the life and reliability of the battery 100. In addition, adding the binding structure 3 to the outside of the bare electrode assembly 2 can protect the electrode assembly 2, eliminate the bottom support sheet at the bottom of the electrode assembly 2 and the outer Mylar film, and increase the reliability of the battery 100.

[0138] In addition, the restraining structure 3 is constrained by the inner wall of the shell 1 to squeeze and fit the electrode assembly 2. The implementation method can be directly extruded on the surface of the electrode assembly 2; it can also be indirectly extruded on the surface of the electrode assembly 2, for example: an intermediate structure is set between the electrode assembly 2 and the restraining structure 3, and the restraining structure 3 applies pressure to the electrode assembly 2 through the intermediate structure.

[0139] The restraint 31 refers to a structure that squeezes and fits the side of the electrode assembly 2 under the constraint of the inner wall of the shell 1, so that the inside of the electrode assembly 2 is pressurized and the gas generated during the formation process is discharged. In order to make the restraint 31 exert a certain pressure on the electrode assembly 2, it can be designed to be a hard and electrolyte-resistant structure. For example, the material of the restraint 31 can be but not limited to PP (polypropylene), PVC (Polyvinyl chloride), PMMA (PolymethylMethacrylate), etc.

[0140] The surface of the electrode assembly 2 may include a side surface, a top surface, and a bottom surface. Taking a cylindrical battery 100 as an example, the side surface of the electrode assembly 2 is the circumferential side surface of the electrode assembly 2 around its own axis, and the top surface and the bottom surface of the electrode assembly 2 are respectively the two end surfaces of the electrode assembly 2 along the direction of its own axis. Taking a flat battery 100 as an example, the side surface of the electrode assembly 2 is a side surface of the electrode assembly 2 along its own thickness direction Y, and the top surface and the bottom surface of the electrode assembly 2 are respectively the two end surfaces of the electrode assembly 2 along the direction of its own winding axis.

[0141] Depending on the shape of the electrode assembly 2, the side of the restraint 31 facing the electrode assembly 2 may also be different. For example, when the electrode assembly 2 is cylindrical, the side of the restraint 31 may be a cylindrical surface; when the electrode assembly 2 is a flat structure, the side of the restraint 31 may be a flat surface.

[0142] In addition, the restraining structure 3 of this embodiment may be the restraining structure 3 provided in the above embodiments. Therefore, the specific structure of the restraining structure 3 of this embodiment may also directly refer to the above embodiments.

[0143] The fixing part 32 refers to a structure crimped on one end of the electrode assembly 2. When the restraining part 31 abuts between the electrode assembly 2 and the inner wall of the shell 1, the fixing part 32 is pressed on the end of the electrode assembly 2 having the pole ear 21. This not only makes the electrode assembly 2 and the restraining structure 3 tightly combined; but also forms a restraining effect on the side of the electrode assembly 2 having the pole ear 21.

[0144] The end of the electrode assembly 2 having the tab 21 is also the end of the electrode assembly 2 facing the opening 11 of the housing 1 of the battery cell 10. In this way, the tab 21 can be electrically connected to the electrode terminal 61 on the end cover 6 through the opening 11.

[0145] It should also be noted that the fixing member 32 can be provided on one binding member 31 or on two binding members 31. When both binding members 31 have the fixing member 32, the fixing members 32 on the two binding members 31 are crimped onto the same end of the electrode assembly 2.

[0146] The base 33 refers to a structure that supports the electrode assembly 2 between the two restraining members 31. The restraining members 31 can be fixed on the base 33 or can be movable relative to the base 33. When the restraining members 31 are fixed on the base 33, a space matching the size of the electrode assembly 2 can be formed between the two restraining members 31 and the base 33; when the restraining members 31 are movable relative to the base 33, for example: there is a bendable fold between the restraining members 31 and the base 33; or, the restraining members 31 and the base 33 are rotatably connected.

[0147] When the restraining structure 3 further includes a fixing member 32, the fixing member 32 is disposed at an end of the restraining member 31 away from the base 33. When the electrode assembly 2 is supported on the base 33, the fixing member 32 is pressed against an end of the electrode assembly 2 facing away from the base 33. At this time, the fixing member 32 and the base 33 cooperate with each other, so that the electrode assembly 2 is stably confined between the fixing member 32 and the base 33, thereby stably combining the electrode assembly 2 with the restraining structure 3; at the same time, it is also beneficial to improve the restraining effect on the electrode assembly 2.

[0148] Optionally, the restraining member 31 and the base 33 may be an integrated structure or a combined structure. For example, the two may be connected by, but not limited to, bonding, snap-fitting, dovetail joints, and the like.

[0149] With such a design, the restraining members 31 can effectively clamp the battery cell 10, so that the formation and exhaust effect is better; at the same time, during the cyclic charge and discharge, the restraining members 31 on both sides can effectively suppress the gap between the pole pieces in the electrode assembly 2, reduce the lithium ion transport distance, and effectively reduce the probability of lithium deposition on the pole piece wrinkles and lithium deposition on the edge 12, thereby improving the life and performance of the battery 100.

[0150] According to some embodiments of the present application, optionally, please refer to Figure 6 A plurality of through holes 331 are formed through the base 33 .

[0151] The base 33 is provided with through holes 331, which allow the electrolyte outside the binding structure 3 to flow to the electrode assembly 2 through the through holes 331 and infiltrate the inside of the electrode assembly 2. The through holes 331 can be distributed in various ways on the base 33, such as: matrix arrangement, circular arrangement; or irregular close arrangement.

[0152] With such a design, a through hole 331 is introduced on the base 33 , so that the electrolyte can penetrate the electrode assembly 2 through the through hole 331 , so that the battery cell 10 can work stably.

[0153] According to some embodiments of the present application, optionally, please refer to Figure 5 and Fig. 9 The fixing member 32 includes a connecting portion 321 and a crimping portion 322 connected to the connecting portion 321 . The connecting portion 321 is connected to the restraining member 31 . The crimping portion 322 protrudes on one side of the connecting portion 321 toward the electrode assembly 2 and is used to be crimped on one end of the electrode assembly 2 .

[0154] The connecting portion 321 refers to the portion of the fixing member 32 that is connected to the restraining member 31, and the crimping portion 322 refers to the structure of the fixing member 32 that is crimped to the electrode assembly 2. The crimping portion 322 protrudes on the connecting portion 321 toward one side of the electrode assembly 2, so that a slot 323 can be formed between the crimping portion 322 and the connecting portion 321, and the shape of the slot 323 can be roughly L-shaped. When the restraining member 31 is squeezed between the electrode assembly 2 and the inner wall of the shell 1, the slot 323 is clamped on one end of the electrode assembly 2.

[0155] The connecting portion 321 and the crimping portion 322 may be an integrated structure or a combined structure, for example, they may be combined and connected by bolt connection, clamping, riveting, welding, etc.

[0156] Such a design facilitates the fixing member 32 to be crimped onto one end of the electrode assembly 2 , making the combination of the electrode assembly 2 and the restraining structure 3 more stable, thereby improving the restraining effect on the electrode assembly 2 and thus improving the reliability of the battery 100 .

[0157] According to some embodiments of this application, please refer to Figures 1 to 10The present application provides a battery cell 10, which includes a shell 1, an electrode assembly 2, a tensioning member and a restraining structure 3. The shell 1 has an opening 11, and the tensioning member 4 is wrapped around the electrode assembly 2. The restraining structure 3 includes a base 33, two restraining members 31 connected to the base 33 at intervals, and a fixing member 32, and the fixing member 32 is arranged at one end of each restraining member 31 away from the base 33. The electrode assembly 2 is placed on the base 33, and the two restraining members 31 are respectively located on both sides of the electrode assembly 2 along its own thickness direction Y. When the electrode assembly 2 is installed in the shell 1 together with the restraining structure 3, the fixing members 32 on each restraining member 31 are in an open state facing away from the electrode assembly 2; as the shell is continuously inserted, the edge 12 of the shell 1 contacts the fixing member 32, and drives the fixing member 32 to be pressed against the end of the electrode assembly 2 facing the opening 11, so that the edge 12 of the electrode piece in the electrode assembly 2 is buckled and restrained.

[0158] With such a design, after the expansion member 4 wrapped around the outside of the electrode assembly 2 expands, it acts with the restraining member 31 to apply a restraining force to the electrode assembly 2, which helps to exhaust gas during the formation process. At the same time, during charging and discharging, the large surface 22 of the electrode assembly 2 is restrained by the restraining member 31, and one end of the electrode assembly 2 is restrained by the fixing member 32, which is beneficial to reducing the lithium ion transportation distance between the pole pieces, reducing the risk of lithium deposition from the pole piece wrinkles and the edge 12, and improving the life and performance of the battery 100.

[0159] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0160] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: Housing (1); An electrode assembly (2) is accommodated in the housing (1); The restraining structure is located in the shell (1) and wrapped around the surface of the electrode assembly (2). The restraining structure is configured to be pressed and matched with the surface of the electrode assembly (2) under the constraint of the inner wall of the shell (1).

2. The battery cell according to claim 1, characterized in that: The binding structure comprises two binding members (31) arranged in parallel and spaced apart, at least one of the electrode assemblies (2) being accommodated between the two binding members (31), and each binding member (31) is pressed and matched with a side surface of the electrode assembly (2).

3. The battery cell according to claim 2, characterized in that: The electrode assembly (2) is constructed as a cylindrical structure, and each of the restraining members (31) is extruded and matched with the electrode assembly (2) along a circumferential side surface around its own axis.

4. The battery cell according to claim 2, characterized in that: The electrode assembly (2) is constructed as a flat structure, and each of the restraining members (31) is extruded and matched with a side surface of the electrode assembly (2) along its own thickness direction (Y).

5. The battery cell according to claim 2, characterized in that: The restraining structure further comprises a fixing member (32), wherein the fixing member (32) is arranged on at least one of the restraining members (31), and one end of the shell (1) along a preset direction (X) has an opening (11), and the fixing member (32) is at least partially crimped to one end of the electrode assembly (2) facing the opening (11).

6. The battery cell according to claim 5, characterized in that: The fixing member (32) comprises a connecting portion (321) and a crimping portion (322) connected to the connecting portion (321); the connecting portion (321) is connected to the restraining member (31); the crimping portion (322) protrudes on the connecting portion (321) along a side facing the electrode assembly (2) and is used for crimping onto one end of the electrode assembly (2).

7. The battery cell according to claim 5, characterized in that: On the restraining member (31) connected to the fixing member (32), the fixing member (32) includes a plurality of fixing members (32), all of which are distributed in sequence along a direction intersecting the preset direction (X) and are used for crimping onto one end of the electrode assembly (2).

8. The battery cell according to claim 5, characterized in that: The fixing member (32) is constructed as a structure that can rotate or deform relative to the restraining member (31), and an edge (12) of the shell (1) surrounding the opening (11) is configured to drive the fixing member (32) to be pressed against one end of the electrode assembly (2).

9. The battery cell according to claim 5, characterized in that: The dimension of the restraining member (31) in the preset direction (X) is greater than the dimension of the fixing member (32) in the preset direction (X).

10. The battery cell according to claim 9, characterized in that: The dimension of the restraining member (31) in the preset direction (X) is recorded as L1, and the dimension of the fixing member (32) in the preset direction (X) is recorded as L2, wherein 8≤L1 / L2≤15.

11. The battery cell according to claim 10, characterized in that: The condition that the size L1 satisfies is: 80mm≤L1≤210mm; Optionally, the dimension L1 also satisfies the condition: 100 mm ≤ L1 ≤ 170 mm.

12. The battery cell according to any one of claims 2 to 11, characterized in that: The restraining structure further comprises a base (33), on which the two restraining members (31) are arranged at intervals, and the base (33) is used to support the electrode assembly (2).

13. The battery cell according to claim 12, characterized in that: The base (33) is penetrated by a plurality of through holes (331).

14. The battery cell according to claim 12, characterized in that: The battery cell further comprises an elastic member (5), wherein the elastic member (5) is arranged in the housing (1) and abuts against a side surface of the base (33) facing away from the electrode assembly (2).

15. The battery cell according to any one of claims 1 to 11, characterized in that: The battery cell also includes a tightening member (4), which is arranged on the surface of the electrode assembly (2) and abuts against the restraining structure.

16. The battery cell according to claim 15, characterized in that: The expansion element (4) is constructed as a structure capable of volume expansion.

17. A battery, characterized in that: The battery comprises the battery cell according to any one of claims 1 to 16.

18. An electrical device, characterized in that: The electrical device comprises the battery according to claim 17.

19. A restraint structure, characterized in that: The restraining structure comprises: Base (33); Two restraining members (31) are arranged on the base (33) at intervals, and are used to accommodate at least one electrode assembly (2) therebetween; A fixing member (32) is provided at one end of at least one of the restraining members (31) away from the base (33), and at least part of the fixing member (32) is used for crimping onto one end of the electrode assembly (2) having a pole ear (21).

20. The restraining structure according to claim 19, characterized in that: The base (33) is penetrated by a plurality of through holes (331).

21. The restraint structure according to claim 19, characterized in that: The fixing member (32) comprises a connecting portion (321) and a crimping portion (322) connected to the connecting portion (321); the connecting portion (321) is connected to the restraining member (31); the crimping portion (322) protrudes on the connecting portion (321) along a side facing the electrode assembly (2) and is used for crimping onto one end of the electrode assembly (2).

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