Battery cell, battery, electric device, and method for manufacturing battery cell

Abstract

Embodiments of the present application provide a battery monomer, a battery, an electric device, a method for preparing a battery monomer and an apparatus for preparing a battery monomer. The battery monomer comprises: a pressure relief mechanism arranged on at least one wall of the battery monomer, the pressure relief mechanism being used to actuate to release internal pressure when the internal pressure or temperature of the battery monomer reaches a threshold value; and a protective film covering an outer surface of the at least one wall, the protective film being used to provide insulation protection for the at least one wall; wherein the protective film comprises a first part covering at least the pressure relief mechanism. Through the technical solution of the embodiments of the present application, the insulation performance of the battery monomer can be improved, and at the same time, the deformation of the pressure relief mechanism can be inhibited, the creep of the pressure relief mechanism can be reduced, and the service life thereof can be improved.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. In this context, electric vehicles, due to their energy-saving and environmentally friendly advantages, have become a crucial component of the industry's sustainable development. Battery technology, in turn, is a crucial factor in the development of electric vehicles.

[0003] In the development of battery technology, in addition to improving battery performance, safety is also an issue that cannot be ignored. If battery safety cannot be guaranteed, the battery will be unusable. Therefore, how to enhance battery safety is a technical issue that needs to be addressed urgently in battery technology. Summary of the Invention

[0004] The present application provides a battery cell, a battery, an electrical device, and a method for preparing the battery cell, which can enhance the safety of the battery.

[0005] In a first aspect, a battery cell is provided, comprising: a pressure relief mechanism, the pressure relief mechanism being arranged on at least one wall of the battery cell, the pressure relief mechanism being used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; a protective film covering the outer surface of the at least one wall, the protective film being used to provide insulating protection for the at least one wall; wherein the protective film comprises a first portion, the first portion at least covering the pressure relief mechanism.

[0006] In an embodiment of the present application, by providing a protective film covering the outer surface of at least one wall of the battery cell, the battery cell can be insulated and protected, thereby improving its insulation performance. At the same time, the protective film covers at least the first part of the pressure relief mechanism, which can inhibit the deformation of the pressure relief mechanism within a certain degree, reduce the creep of the pressure relief mechanism, thereby increasing its service life and enhancing the safety performance of the battery.

[0007] In some embodiments, the area of ​​the first portion is larger than the area of ​​the region where the pressure relief mechanism is located, and the region of the first portion exceeding the pressure relief mechanism is bonded to the outer surface of the at least one wall.

[0008] By setting the area of ​​the first part to be larger than the area of ​​the region where the pressure relief mechanism is located, and by bonding the region of the first part not covering the pressure relief mechanism to at least one wall, the adhesion force generated between the first part and at least one wall can suppress the deformation of the pressure relief mechanism, reduce the creep of the pressure relief mechanism, thereby increasing its service life and further enhancing the safety performance of the battery.

[0009] In some embodiments, the shape of the first portion is the same as or similar to the shape of the pressure relief mechanism.

[0010] By setting the first part to have the same or similar shape as the pressure relief mechanism, it can be ensured that the force generated by the deformation of the pressure relief mechanism on the protective film is uniform, which is more conducive to the first part suppressing the deformation of the pressure relief mechanism.

[0011] In some embodiments, the edge of the first portion extends beyond the edge of the pressure relief mechanism by 6 mm to 10 mm in a direction away from the center of the pressure relief mechanism.

[0012] By setting a suitable size for the edge of the first part to extend beyond the edge of the pressure relief mechanism, it can be ensured that the first part can inhibit the deformation of the pressure relief mechanism within a certain degree. At the same time, it can also be ensured that when the pressure and temperature inside the battery cell reach a certain threshold, the first part can be destroyed and fall off, thereby ensuring the normal actuation of the pressure relief mechanism and not affecting the normal use of the pressure relief mechanism, thereby ensuring the safety of the battery.

[0013] In some embodiments, at least one wall of the battery cell includes a shell, the shell forms a receiving cavity with an opening for receiving the electrode assembly of the battery cell, and the protective film covers an outer surface of the shell.

[0014] The battery cell in the embodiment of the present application may include a shell, wherein the shell may be a accommodating cavity with an opening composed of five walls except for the cover plate. The protective film in the embodiment of the present application may completely or largely cover the outer surface of the above-mentioned shell, thereby providing insulation protection for the battery cell.

[0015] In some embodiments, the protective film further includes an isolation region and a second portion, the first portion is separated from the second portion by the isolation region, and the second portion covers the outer surface of the at least one wall except for the region covered by the first portion.

[0016] In addition to the first part, the protective film in the embodiment of the present application also includes a second part, wherein the first part and the second part are separated by an isolation area, and the second part can cover the area on the battery cell other than that covered by the first part. Therefore, in the embodiment of the present application, the protective film can suppress the deformation of the pressure relief mechanism through the first part, and the second part of the protective film can simultaneously achieve insulation protection for the battery cell.

[0017] In some embodiments, the isolation region is disposed around an outer edge of the pressure relief mechanism.

[0018] The isolation area arranged around the edge of the pressure relief mechanism can separate the protective film into a first portion covering the pressure relief mechanism and a second portion not covering the pressure relief mechanism.

[0019] In some embodiments, the isolation region is continuous, and the first portion is not connected to the second portion.

[0020] In an embodiment of the present application, when the isolation area is a continuous area without connection points, relying on the portion where the edge of the first part is bonded to the surface of at least one wall, the first part can have a certain degree of inhibitory effect on the deformation of the pressure relief mechanism, reduce the creep of the pressure relief mechanism, thereby increasing its service life and further enhancing the safety performance of the battery.

[0021] In some embodiments, the isolation region is non-continuous, a connection point is provided between the first portion and the second portion, and the first portion and the second portion are connected through the connection point.

[0022] The isolation area in the embodiment of the present application may also be non-continuous, and the first part may be connected to the second part through a connection point. Due to the existence of the connection point, there is a constraint force between the first part and the second part, and this constraint force can have a certain degree of inhibitory effect on the deformation of the pressure relief mechanism.

[0023] In some embodiments, the number of the connection points is directly proportional to the extent to which the edge of the first portion extends beyond the edge of the pressure relief mechanism in a direction away from the center of the pressure relief mechanism.

[0024] When there are connection points, there will be a constraint force between the first part and the second part, and this constraint force can suppress the deformation of the pressure relief mechanism. Moreover, as the number of connection points increases, the constraint force will also increase. At the same time, since there is a certain constraint force between the position where the first part exceeds the edge of the pressure relief mechanism and the surface of at least one wall of the battery elevator, this constraint force increases as the area of ​​the overlapping region increases. Therefore, the above two methods can be combined to determine the appropriate number of connection points and the size of the first part exceeding the edge of the pressure relief mechanism. For example, when the number of connection points is large, a smaller size exceeding the edge can be set so that the first part can ensure that the deformation of the pressure relief mechanism is suppressed within a certain degree, and can ensure the normal operation of the pressure relief mechanism.

[0025] In some embodiments, the battery cell includes two electrode terminals with opposite polarities, and at least two connection points are provided along a connection direction of the two electrode terminals.

[0026] It should be understood that in a battery cell, when there are electrode terminals, the position where the battery cell has the largest deformation may appear in the direction along the line connecting the two battery terminals. Therefore, the connection point can be set in the direction of the line connecting the two electrode terminals to achieve a better effect of suppressing the deformation of the pressure relief mechanism.

[0027] In some embodiments, the protective film is a patch, and the protective film is adhered to the outer surface of the at least one wall by an adhesive.

[0028] The protective film in the embodiment of the present application can be a patch, such as a plastic patch, or a blue film, etc. The patch can be adhered to the surface of at least one wall by an adhesive. Through the bonding effect between the protective film and at least one wall, the deformation of the pressure relief mechanism can be effectively suppressed, the creep of the pressure relief mechanism can be reduced, and thus its service life can be improved.

[0029] In some embodiments, the first portion is spaced apart from the pressure relief mechanism.

[0030] When the protective film in the embodiment of the present application is a patch, since the patch is directly bonded to the surface of at least one wall, when the pressure relief mechanism in the embodiment of the present application is recessed into the surface of at least one wall of the battery cell, there can be a gap between the first part and the pressure relief mechanism. This gap can suppress the deformation of the pressure relief mechanism to a certain extent by the first part, thereby reducing the creep of the pressure relief mechanism and thus improving its service life.

[0031] In some embodiments, the isolation region is formed by laser ablation of the protective film.

[0032] When the protective film in the embodiment of the present application is a patch, the protective film can be processed by a laser ablation process to form an isolation area that isolates the first part and the second part. The laser ablation process can be used to adjust the movement trajectory and ablation power of the laser head according to the size and shape of the first part on the basis of the existing process, without the need for repeated mold opening, thereby reducing processing costs.

[0033] In some embodiments, the protective film is a coating, and the protective film is applied to the outer surface of the at least one wall and the pressure relief mechanism by spraying.

[0034] The protective film in the embodiment of the present application can be a coating. In this case, the coating can be applied to at least one wall of the battery cell by spraying. Since the coating is sprayed, the coating and the pressure relief mechanism can be in direct contact, that is, the coating is directly covered on the surface of the pressure relief mechanism. In this case, since the coating is directly applied to the surface of the pressure relief mechanism, there will be a restraining force between the coating and the surface of the pressure relief mechanism, and this restraining force can inhibit the deformation of the pressure relief mechanism.

[0035] In some embodiments, the isolation area is formed by reserving some areas for non-coating when coating the protective film on the surfaces of the at least one wall and the pressure relief mechanism.

[0036] When the protective film in the embodiment of the present application is a coating, the isolation area on the protective film can be a certain area reserved for not coating when spraying the coating to form an isolation area. For example, a mold of a certain shape can be pre-placed at the position where the isolation area is formed to prevent the coating from being coated at the position of the isolation area.

[0037] In some embodiments, the thickness of the first portion is greater than the thickness of the second portion.

[0038] When the protective film in the embodiment of the present application is a coating, within a certain range, the greater the thickness of the coating, the greater the constraint force it generates with the pressure relief mechanism. Therefore, the first part can be set to have a larger thickness to better suppress the deformation of the pressure relief mechanism.

[0039] In a second aspect, a battery is provided, comprising: a plurality of battery cells, wherein the plurality of battery cells include the battery cell according to the first aspect; wherein the plurality of battery cells are insulated from each other by the protective film.

[0040] In a third aspect, an electrical device is provided, comprising: the battery described in the second aspect.

[0041] In some embodiments, the electrical device is a vehicle, a ship, or a spacecraft.

[0042] In a fourth aspect, a method for preparing a battery cell is provided, comprising: providing a pressure relief mechanism on at least one wall of the battery cell, the pressure relief mechanism being configured to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; and covering the outer surface of the at least one wall with a protective film, the protective film being configured to provide insulating protection for the at least one wall; wherein the protective film comprises a first portion, the first portion at least covering the pressure relief mechanism.

[0043] In some embodiments, the area of ​​the first portion is larger than the area of ​​the region where the pressure relief mechanism is located, and the region of the first portion exceeding the pressure relief mechanism is bonded to the outer surface of the at least one wall.

[0044] In some embodiments, the shape of the first portion is configured to be the same as or similar to the shape of the pressure relief mechanism.

[0045] In some embodiments, the edge of the first portion is arranged to extend beyond the edge of the pressure relief mechanism by 6 mm to 10 mm in a direction away from the center of the pressure relief mechanism.

[0046] In some embodiments, at least one wall of the battery cell includes a shell, the shell forms a receiving cavity with an opening for receiving the electrode assembly of the battery cell, and the protective film is coated on an outer surface of the shell.

[0047] In some embodiments, the protective film also includes an isolation area and a second part, the first part is separated from the second part by the isolation area, and the protective film covering the outer surface of the at least one wall includes: making the second part cover the outer surface of the at least one wall except the area covered by the first part.

[0048] In some embodiments, the isolation region is disposed around an outer edge of the pressure relief mechanism.

[0049] In some embodiments, the isolation region is continuous, and the first portion is not connected to the second portion.

[0050] In some embodiments, the isolation region is non-contiguous, and a connection point is provided between the first portion and the second portion to form the non-contiguous isolation region, wherein the first portion and the second portion are connected via the connection point.

[0051] In some embodiments, the number of the connection points is directly proportional to the extent to which the edge of the first portion extends beyond the edge of the pressure relief mechanism in a direction away from the center of the pressure relief mechanism.

[0052] In some embodiments, the battery cell includes two electrode terminals with opposite polarities, and at least two connection points are provided along a connection direction of the two electrode terminals.

[0053] In some embodiments, the protective film is a patch, and covering the outer surface of the at least one wall with the protective film includes: bonding the protective film to the outer surface of the at least one wall by an adhesive.

[0054] In some embodiments, the first portion is spaced apart from the pressure relief mechanism.

[0055] In some embodiments, after the protective film is bonded to the outer surface of the at least one wall by an adhesive, the protective film is ablated by laser to form the isolation region.

[0056] In some embodiments, the protective film is a coating, and coating the outer surface of the at least one wall with the protective film includes: applying the protective film to the outer surfaces of the at least one wall and the pressure relief mechanism by spraying.

[0057] In some embodiments, coating the outer surface of the at least one wall with a protective film further comprises: when coating the protective film on the outer surfaces of the at least one wall and the pressure relief mechanism, reserving some areas without coating to form the isolation area.

[0058] In some embodiments, the coating thickness of the first portion is set to be greater than the coating thickness of the second portion.

[0059] In a fifth aspect, a device for preparing a battery cell is provided, comprising: a setting module, wherein the setting module is used to: set a pressure relief mechanism on at least one wall of the battery cell, wherein the pressure relief mechanism is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; and cover the outer surface of the at least one wall with a protective film, wherein the protective film is used to provide insulating protection for the at least one wall; wherein the protective film includes a first part, and the first part at least covers the pressure relief mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0061] Figure 1 This is a schematic structural diagram of a vehicle disclosed in one embodiment of the present application;

[0062] Figure 2 This is a schematic structural diagram of a battery disclosed in one embodiment of the present application;

[0063] Figure 3 This is a schematic structural diagram of a battery cell group disclosed in one embodiment of the present application;

[0064] Figure 4 This is an exploded view of a battery cell disclosed in one embodiment of the present application;

[0065] Figure 5 is an exploded view of a battery cell disclosed in another embodiment of the present application;

[0066] Figure 6 This is a distribution diagram of a pressure relief mechanism disclosed in one embodiment of the present application;

[0067] Figure 7a is a schematic diagram of a battery cell disclosed in one embodiment of the present application;

[0068] Figure 7b corresponds to Figure 7a A schematic plan view of a battery cell;

[0069] Figure 7c It is a local detail image corresponding to the protective film;

[0070] Figure 8 It is a plan view of an isolation area disclosed in one embodiment of the present application;

[0071] Figure 9 is a plan view of another isolation area disclosed in an embodiment of the present application;

[0072] Figure 10 is a plan view of another isolation area disclosed in an embodiment of the present application;

[0073] Figure 11 is a planar schematic diagram of a protective film disclosed in one embodiment of the present application;

[0074] Figure 12 is a planar schematic diagram of a protective film disclosed in one embodiment of the present application;

[0075] Figure 13 is a schematic flow chart of a method for preparing a battery cell disclosed in one embodiment of the present application;

[0076] Figure 14 This is a schematic block diagram of an apparatus for preparing a battery cell disclosed in one embodiment of the present application.

[0077] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0078] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0079] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0080] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0081] The protective film of the embodiment of the present application can be used to wrap a battery cell. The protective film can be an insulating and waterproof material to be used for insulating, isolating and waterproofing the battery cell. The protective film can also wrap a battery assembly, which can be a battery cell, or an assembly formed by battery cells, for example, a battery cell group formed by multiple adjacent battery cells. In this case, the adjacent multiple battery cells are entirely wrapped with the protective film of the embodiment of the present application. For ease of description, the following description uses the protective film wrapped around a battery cell as an example, but the embodiment of the present application is not limited to this.

[0082] The protective film in the embodiment of the present application can be coated on at least one wall of the battery cell during the molding process of the battery cell, after completing steps such as performance testing of the battery cell, so as to provide insulation protection for the battery cell.

[0083] Optionally, the protective film in the embodiment of the present application may be a blue film commonly used in the battery field.

[0084] In this application, battery cells may include primary batteries and secondary batteries, such as lithium-ion batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., which are not limited in this embodiment of the application. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., which are not limited in this embodiment of the application. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, which are not limited in this embodiment of the application.

[0085] 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. A battery pack generally includes a housing that encloses one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0086] A battery cell comprises an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet comprises a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer, and the current collector uncoated with the positive active material layer serves as the positive electrode tab. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet comprises 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 current collector uncoated with the negative active material layer protrudes from the current collector coated with the negative active material layer, and the 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, the positive electrode tabs are multiple and stacked together, and the negative electrode tabs are multiple and stacked together. The protective film can be made of polypropylene (PP) or polyethylene (PE), etc. In addition, the electrode assembly can be a wound structure or a laminated structure, but the embodiments of the present application are not limited to this. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge and discharge rate. In addition, battery safety must also be considered.

[0087] For batteries, the main safety hazards come from the charging and discharging processes. In order to improve the safety performance of the battery, a pressure relief mechanism is generally provided for the battery cell. The pressure relief mechanism refers to an element or component that is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a predetermined threshold. The predetermined threshold can be adjusted according to different design requirements. The predetermined threshold may depend on one or more materials of the positive electrode plate, negative electrode plate, electrolyte and separator in the battery cell. The pressure relief mechanism can adopt, for example, an element or component that is sensitive to pressure or temperature, that is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism is actuated, thereby forming a channel for the internal pressure or temperature to be released.

[0088] The term "activation" as used in this application refers to the action of the pressure relief mechanism, which allows the internal pressure and temperature of the battery cell to be released. The action of the pressure relief mechanism may include, but is not limited to, rupturing, tearing, or melting of at least a portion of the pressure relief mechanism. After the pressure relief mechanism is activated, the high-temperature and high-pressure substances inside the battery cell are discharged from the pressure relief mechanism as emissions. In this way, the pressure of the battery cell can be relieved under controllable pressure or temperature, thereby avoiding potentially more serious accidents.

[0089] The emissions from battery cells mentioned in this application include but are not limited to: electrolyte, dissolved or split positive and negative electrode plates, fragments of separators, high-temperature and high-pressure gases generated by the reaction, flames, etc.

[0090] The pressure relief mechanism on a battery cell has a significant impact on battery safety. For example, a short circuit or overcharge in a battery cell can cause thermal runaway within the cell, leading to a sudden increase in pressure or temperature. In this situation, the pressure relief mechanism activates to release internal pressure and temperature, preventing explosion or fire.

[0091] Current pressure relief mechanisms, when activated, release internal pressure or temperature to the outside, ensuring the safety of the battery cells. However, before activation, the pressure relief mechanism undergoes creep deformation under long-term stress and increasing temperatures. This creep phenomenon manifests itself microscopically as grain boundary slippage and grain diffusion along the grain boundaries, ultimately causing the pressure relief mechanism to become thinner, reducing its pressure-bearing capacity. This deformation results in thinning areas within the pressure relief mechanism. Over time, the deformation of the pressure relief mechanism increases, reducing the actuation pressure. If the deformation of the pressure relief mechanism is not controlled, when it reaches a certain level, creep failure, resulting in tearing, will occur, shortening the service life of the pressure relief mechanism and, consequently, the battery. Furthermore, this creep failure phenomenon is subtle and difficult to detect, making it difficult to detect a failed pressure relief mechanism, significantly impacting battery safety.

[0092] In view of this, an embodiment of the present application provides a technical solution, in which at least one wall of a battery cell including a pressure relief mechanism is covered with a protective film, wherein the first portion included in the protective film at least covers the pressure relief mechanism. On the one hand, by covering the battery cell, the surface of the battery cell can be insulated and protected, thereby improving the insulation isolation performance of the battery cell. On the other hand, by covering the pressure relief mechanism of the battery cell, the protective film can suppress the deformation of the pressure relief mechanism, thereby reducing the creep amount of the pressure relief mechanism, increasing its service life, and thereby improving the safety of the battery.

[0093] The technical solutions described in the embodiments of the present application are applicable to various battery-using devices, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0094] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the devices described above, but can also be applied to all devices using batteries. However, for the sake of simplicity, the following embodiments are explained using electric vehicles as an example.

[0095] For example, Figure 1 As shown, it is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 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 motor 40, a controller 30 and a battery 10 can be provided inside the vehicle 1. The controller 30 is used to control the battery 10 to supply power to the motor 40. For example, a battery 10 can be provided at the bottom, front or rear of the vehicle 1. The battery 10 can be used to power the vehicle 1. For example, the battery 10 can be used as an operating power source for the vehicle 1, for the circuit system of the vehicle 1, for example, for the working power requirements of the vehicle 1 during startup, navigation and operation. In another embodiment of the present application, the battery 10 can not only serve as an operating power source for the vehicle 1, but also as a driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving force for the vehicle 1.

[0096] To meet different power requirements, a battery can include multiple battery cells, which can be connected in series, parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections. A battery can also be referred to as a battery pack. Alternatively, multiple battery cells can be connected in series, parallel, or in a hybrid configuration to form a battery module, which can then be connected in series, parallel, or in a hybrid configuration to form a battery. In other words, multiple battery cells can be directly connected to form a battery, or they can be first connected to form battery modules, which can then be connected to form a battery.

[0097] For example, Figure 2 As shown in FIG. 1 , a schematic diagram of the structure of a battery 10 according to an embodiment of the present application is provided. The battery 10 may include a plurality of battery cells 20. The battery 10 may also include a housing (or cover), the interior of the housing being a hollow structure, and the plurality of battery cells 20 being accommodated in the housing. Figure 2As shown, the box body may include two parts, referred to herein as a first part 111 and a second part 112, which are buckled together. The shapes of the first part 111 and the second part 112 may be determined according to the shape of the combination of multiple battery cells 20, and the first part 111 and the second part 112 may each have an opening. For example, the first part 111 and the second part 112 may both be hollow cuboids and each have only one open face, the opening of the first part 111 and the opening of the second part 112 are arranged relative to each other, and the first part 111 and the second part 112 are buckled together to form a box body with a closed chamber. Multiple battery cells 20 are connected in parallel, in series, or in a mixed combination and are placed in the box body formed by buckling the first part 111 and the second part 112.

[0098] Optionally, the battery 10 may also include other structures, which will not be described in detail here. For example, the battery 10 may also include a busbar component, which is used to achieve electrical connection between multiple battery cells 20, such as parallel, series, or mixed connection. Specifically, the busbar component can achieve electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20. Furthermore, the busbar component can be fixed to the electrode terminals of the battery cells 20 by welding. The electrical energy of the multiple battery cells 20 can be further led out through the box through the conductive mechanism.

[0099] The number of battery cells 20 can be set to any value according to different power requirements. Multiple battery cells 20 can be connected in series, parallel or mixed to achieve a larger capacity or power. Since the number of battery cells 20 included in each battery 10 may be large, in order to facilitate installation, the battery cells 20 can be grouped and each group of battery cells 20 forms a battery module. The number of battery cells 20 included in the battery module is not limited and can be set according to requirements. For example, Figure 3 A battery may include multiple battery modules, which may be connected in series, parallel, or in a hybrid manner.

[0100] like Figure 4, which is a schematic structural diagram of a battery cell 20 according to an embodiment of the present application. The battery cell 20 includes one or more electrode assemblies 22, a shell 211, and a cover plate 212. The shell 211 and the cover plate 212 form an outer shell 21. The walls of the shell 211 and the cover plate 212 are both referred to as walls of the battery cell 20. The shell 211 is determined by the shape of the one or more electrode assemblies 22 after assembly. For example, the shell 211 can be a hollow cuboid, cube, or cylinder, and one of the faces of the shell 211 has an opening so that the one or more electrode assemblies 22 can be placed in the shell 211. For example, when the shell 211 is a hollow cuboid or cube, one of the planes of the shell 211 is an open face, that is, the plane does not have a wall, so that the inside and outside of the shell 211 are in communication. When the shell 211 is a hollow cylinder, the end face of the shell 211 is an open face, that is, the end face does not have a wall, so that the inside and outside of the shell 211 are in communication. The cover plate 212 covers the opening and is connected to the housing 211 to form a closed cavity for placing the electrode assembly 22. The housing 211 is filled with an electrolyte, such as an electrolyte solution.

[0101] The battery cell 20 may further include an electrode terminal 214, which may be provided on the cover plate 212. One end of the electrode terminal 214 is connected to the electrode assembly 22 inside the housing 211, and the other end is connected to an electrical device or an external power source outside the housing 211, for outputting electrical energy from the battery cell 20 or charging the battery cell 20. The cover plate 212 is generally in the shape of a flat plate, and the electrode terminal 214 may include two electrode terminals 214, such as Figure 4 As shown, two electrode terminals 214 are fixed on the flat surface of the cover plate 212. The two electrode terminals 214 are respectively a positive electrode terminal 214a and a negative electrode terminal 214b, or 214a and 214b can also be electrode terminals of opposite polarities. This embodiment of the present application does not limit this.

[0102] In the battery cell 20, the electrode assembly 22 can be provided as a single one or multiple ones according to actual use requirements, such as Figure 4 As shown, four independent electrode assemblies 22 are provided in the battery cell 20 .

[0103] like Figure 5 , which is a structural diagram of a battery cell 20 including a pressure relief mechanism 213 according to another embodiment of the present application.

[0104] Figure 5 The shell 211, cover plate 212 and electrode assembly 22 in Figure 4 The shell 211, cover plate 212 and electrode assembly 22 are consistent, and for the sake of brevity, they are not repeated here.

[0105] A wall of the battery cell 20, such as Figure 5A pressure relief mechanism 213 may also be provided on the first wall 21 a as shown. Figure 5 In the embodiment, the bottom side of the housing 211 has an opening. The first wall 21a covers the bottom opening and is connected to the housing 211. The connection method may be welding or gluing. Alternatively, the first wall 21a and the housing 211 may be an integral structure. The pressure relief mechanism 213 is used to activate and release the internal pressure or temperature of the battery cell 20 when the internal pressure or temperature reaches a threshold value.

[0106] The pressure relief mechanism 213 can be part of the first wall 21a or a separate structure from the first wall 21a, secured to the first wall 21a by, for example, welding. When the pressure relief mechanism 213 is part of the first wall 21a, for example, it can be formed by providing a notch in the first wall 21a, with the thickness of the first wall 21a corresponding to the notch being less than the thickness of the pressure relief mechanism 213 in areas other than the notch. The notch is the weakest point of the pressure relief mechanism 213. When excessive gas generated by the battery cells 20 causes the pressure inside the housing 211 to rise and reach a threshold, or when heat generated by reactions within the battery cells 20 causes the temperature inside the battery cells 20 to rise and reach a threshold, the pressure relief mechanism 213 can rupture at the notch, opening the housing 211 to the outside. The gas pressure and temperature are released outward through the rupture of the pressure relief mechanism 213, thereby preventing the battery cells 20 from exploding.

[0107] Optionally, in one embodiment of the present application, Figure 5 As shown, when the pressure relief mechanism 213 is provided on the first wall 21 a of the battery cell 20 , the electrode terminal 214 is provided on the other wall of the battery cell 20 , and the wall where the electrode terminal 214 is provided is different from the first wall 21 a .

[0108] Optionally, the wall where the electrode terminal 214 is provided is opposite to the first wall 21 a . For example, the first wall 21 a may be the bottom wall of the battery cell 20 , and the wall where the electrode terminal 214 is provided may be the cover plate 212 of the battery cell 20 .

[0109] Alternatively, as Figure 5As shown, the battery cell 20 may further include a backing plate 24, which is located between the electrode assembly 22 and the bottom wall of the housing 211. The backing plate 24 can support the electrode assembly 22 and effectively prevent interference between the electrode assembly 22 and the rounded corners around the bottom wall of the housing 211. In addition, the backing plate 24 may be provided with one or more through holes. For example, multiple through holes may be evenly arranged. Alternatively, when the pressure relief mechanism 213 is provided on the bottom wall of the housing 211, through holes may be provided corresponding to the positions of the pressure relief mechanism 213 to facilitate the conduction of electrolyte or gas. Specifically, this allows the spaces between the upper and lower surfaces of the backing plate 24 to be connected, and the gas and electrolyte generated inside the battery cell 20 can freely pass through the backing plate 24.

[0110] By arranging the pressure relief mechanism 213 and the electrode terminal 214 on different walls of the battery cell 20, when the pressure relief mechanism 213 is actuated, the discharge of the battery cell 20 can be further away from the electrode terminal 214, thereby reducing the impact of the discharge on the electrode terminal 214 and the busbar component, thereby enhancing the safety of the battery.

[0111] The pressure relief mechanism 213 may be any of various possible pressure relief mechanisms, and the embodiments of the present application are not limited thereto. For example, the pressure relief mechanism 213 may be a temperature-sensitive pressure relief mechanism configured to melt when the internal temperature of the battery cell 20 on which the pressure relief mechanism 213 is provided reaches a threshold; and / or the pressure relief mechanism 213 may be a pressure-sensitive pressure relief mechanism configured to rupture when the internal pressure of the battery cell 20 on which the pressure relief mechanism 213 is provided reaches a threshold.

[0112] In the above embodiment, the pressure relief mechanism 213 is located on the first wall 21a of the housing 211. Optionally, the pressure relief mechanism 213 in the embodiment of the present application may also be located on the cover plate 212, or the pressure relief mechanism 213 may also be located on the side wall of the housing 211, or the pressure relief mechanism 213 may also be provided at the corner of the housing 211, for example, at the portion where two intersecting walls of the housing 211 are connected to each other, such as Figure 6 FIG. 1 is a schematic diagram showing a pressure relief mechanism located at a corner of a housing in an embodiment of the present application. Specifically, Figure 6 As shown, a pressure relief mechanism 213 may be provided at the junction of the first wall 21 a and the side wall 21 b . The present application does not limit the position of the pressure relief mechanism 213 .

[0113] In the current pressure relief mechanism 213 scheme, the pressure relief mechanism 213 can release the internal pressure or temperature outward after actuation to ensure the safety performance of the battery cell 20. However, before actuation, the pressure relief mechanism 213 will be affected by the internal temperature and pressure of the battery and undergo creep deformation. Excessive deformation will cause the pressure relief mechanism to creep failure, thereby reducing the service life of the pressure relief mechanism 213.

[0114] Furthermore, within the battery 10, the chemical system produces gas as the chemical reaction proceeds. When the chemical reaction occurs within the battery 10 and produces gas, the amount of gas within the battery 10 increases. Since the entire battery 10 is sealed, the chemical gas will cause the internal air pressure of the battery 10 to gradually increase over the entire life cycle of the battery 10. During use, the battery 10 undergoes charging, discharging, and storage conditions. Under different operating conditions, the temperature of the battery 10 itself will undergo a cyclical increase-decrease-increase pattern, causing the air pressure within the battery casing to cyclically change with temperature. The pressure relief mechanism, as the weakest area of ​​the entire casing structure, will experience breathing deformation as a result of these pressure changes. This breathing deformation of the pressure relief mechanism 213 caused by the operating conditions of the battery cell 20 can cause the pressure relief mechanism 213 to experience breathing fatigue during use. If the deformation is large, the pressure relief mechanism 213 will also fail due to breathing deformation. Moreover, when the pressure relief mechanism 213 is located on the wall of the shell 211 other than the cover plate 212, since the wall of the shell 211 is generally thinner than the cover plate 212, the wall of the shell 211 where the pressure relief mechanism 213 is located will also undergo significant deformation. Therefore, when the pressure relief mechanism 213 is located on the wall of the shell 211, its deformation during use will be greater than the deformation of the pressure relief mechanism 213 when it is located on the cover plate 212.

[0115] In response to the above-mentioned problem, the present application utilizes a protective film to cover at least one wall of the battery cell 20 including the pressure relief mechanism 213, wherein the protective film can cover the pressure relief mechanism 213. On the one hand, by covering the surface of the battery cell 20, the battery cell 20 can be insulated and protected, thereby improving the insulation isolation performance of the battery cell 20. On the other hand, by covering the pressure relief mechanism 213 of the battery cell 20, the protective film can limit the deformation of the pressure relief mechanism 213, thereby reducing the creep deformation of the pressure relief mechanism 213 and improving its service life.

[0116] For ease of understanding, the following description is made using an example in which the pressure relief mechanism 213 in the embodiment of the present application is located on the first wall 21 a , but the present application is not limited thereto.

[0117] The battery cell 20 in the embodiment of the present application may include: a pressure relief mechanism 213, which is arranged on at least one wall of the battery cell 20, and the pressure relief mechanism 213 is used to actuate to release the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold; and a protective film 50, covering the outer surface of at least one wall, and the protective film 50 is used to provide insulating protection for at least one wall; wherein the protective film 50 includes a first part 510, and the first part 510 at least covers the pressure relief mechanism 213.

[0118] Figures 7a to 7cA schematic diagram of a battery cell covered with a protective film according to an embodiment of the present application is shown. Figure 7a This is a schematic diagram of a battery cell according to an embodiment of the present application. Figure 7b To correspond to Figure 7a A schematic plan view of a battery cell. Figure 7c This is a local detail image corresponding to the protective film.

[0119] It should be understood that, in order to facilitate intuitive display of the first wall 21a, in the embodiment of the present application, the battery cell 20 in the drawings is placed upside down, that is, the first wall 21a faces upward and the cover plate 212 is located at the bottom. However, the representation in the drawings of the embodiment of the present application is only for the convenience of intuitive display and does not impose any other restrictions on the structure of the battery cell 20. For example, Figure 7a The first wall 21 a faces upward, and the cover plate 212 faces downward, wherein the cover plate 212 may be provided with an electrode terminal 214 and the like.

[0120] like Figures 7a to 7c As shown, the battery cell 20 includes a pressure relief mechanism 213, and the shape of the pressure relief mechanism 213 can be an oblong, circular, elliptical or polygonal shape. Figure 7a and 7b As shown, the pressure relief mechanism 213 is an oblong, and the farthest distance between the two points on the arc at both ends is the long diameter of the oblong, and the direction of the long diameter is parallel to the direction of the line connecting the two electrode terminals 214; of course, the long diameter direction of the pressure relief mechanism 213 can also be set perpendicular to the direction of the line connecting the two electrode terminals. The pressure relief mechanism 213 can include a layer of pressure relief sheet, or it can include multiple layers of pressure relief sheets stacked and spaced apart. The pressure relief sheet can be made of metal foil, such as aluminum foil or copper foil. The pressure relief sheet of the pressure relief mechanism 213 can be a flat thin sheet, which does not occupy the extra volume of the battery cell and improves the energy density; it can also be an arc-shaped or wavy setting, and a certain pre-deformation or pre-stress can be set according to the gas production of the battery cell to offset part of the deformation caused by gas production.

[0121] The pressure relief mechanism 213 is disposed on at least one wall of the battery cell 20. For example, it may be the first wall 21a described above, the side wall 21b of the housing 211, or located at the junction of the first wall 21a and the side wall 21b. Of course, the pressure relief mechanism 213 may also be located on the cover plate 212 of the battery cell 20. The housing 211 of the battery cell 20 may be integrally formed to form a chamber for accommodating the electrode assembly. The electrode assembly is placed into the chamber through the opening of the housing 211, and the cover plate 212 is installed and sealed to the housing 211. The cover plate 212 may be provided with functional components such as electrode terminals and a liquid injection port (not shown). The thickness of the cover plate 212 may be greater than that of the housing 211 to maintain sufficient rigidity and strength.

[0122] The battery cell 20 further includes a protective film 50, which is coated on the outer surface of the first wall 21a. Figure 7a As shown, the protective film can cover most of the area of ​​the first wall 21a, or can completely cover the first wall 21a; of course, it can further cover the side walls of the housing 211 (for example Figure 7a The dashed line portion of the bottom-facing cover plate 212 shown in FIG. 1 indicates that the protective film 50 substantially covers the entire surface of the housing 211, with its edges extending a certain distance from the four sides of the cover plate 212 to ensure that the protective film 50 completely covers the entire outer surface of the housing 211 under a predetermined tension. The protective film 50 may be made of polyester resin or polypropylene and may have a thickness of 0.03 mm to 0.50 mm. Optionally, the protective film 50 may be 0.1 mm thick. It provides insulation protection for the metal cover plate and housing of the battery cell 20.

[0123] During the molding process of the battery cell 20, after completing performance testing and other steps on the battery cell 20, the housing 211 and / or cover plate 212 are covered with a protective film 50, maintaining a complete fit between the protective film 50 and the housing 211 and / or cover plate 212 to prevent bubbles from forming between them. Final dimensional testing is then performed to complete the molding of the battery cell 20. Because the protective film 50 needs to tightly cover the housing 211 and / or cover plate 212 of the battery cell 20 over a large area to provide insulation protection for the battery cell 20, the pressure relief mechanism provided on the housing 211 and / or cover plate 212 can optionally be provided on the inner side of these plates, or the outermost point of the pressure relief mechanism can be provided without protruding from the outer surface of these plates. When a corresponding fixed structure is required to be machined to install the pressure relief mechanism, the outermost point of these fixed structures can optionally also be provided without protruding from the outer surface of these plates. When multiple battery cells 20 are arranged in parallel, series, or mixed to form a battery module or battery pack, it is particularly important to insulate the housings 211 and / or cover plates 212 of the battery cells 20 from each other through the protective film 50 .

[0124] The first portion 510 of the protective film 50 at least covers the pressure relief mechanism 213. When the protective film 50 covers the shell of the battery cell 20 over a large area, it also covers the pressure relief mechanism 213 from the outside of the pressure relief mechanism 213. The portion of the protective film 50 covering the pressure relief mechanism 213 is the first portion 510 of the embodiment of the present application. Figure 7b and 7c As shown, the first portion 510 completely covers the pressure relief mechanism 213 from the outside of the pressure relief mechanism 213 away from the battery cell 20, thereby limiting the deformation of the pressure relief mechanism 213 in the thickness direction of the shell 211, thereby avoiding creep failure and / or breathing failure of the pressure relief mechanism 213 during use.

[0125] By providing the battery cell 20 with a protective film 50 that at least covers the surface of at least one wall of the pressure relief mechanism 213, on the one hand, the surface of the battery cell can be insulated and protected, thereby improving the insulation isolation performance of the battery cell. On the other hand, the first part 510 of the protective film 50 that covers the pressure relief mechanism 213 can be utilized to limit the deformation of the pressure relief mechanism 213, reduce the creep of the pressure relief mechanism 213, and improve its service life.

[0126] At the same time, compared with the prior art solution of installing an additional protective patch on the outside of the pressure relief mechanism, the solution of the embodiment of the present application can directly use the protective film of the battery cell to protect the pressure relief mechanism, which not only has the function of protecting the patch, but also has the function of suppressing deformation. There is no need to additionally process a fixing structure on the housing or cover to fix the protective patch, and no additional protective patch is required, which saves manufacturing materials, reduces processing procedures, and reduces the manufacturing cost of the battery cell.

[0127] As an implementation method, at least one wall of the battery cell 20 in the embodiment of the present application may include a shell 211, which forms a receiving cavity with an opening for accommodating the electrode assembly of the battery cell 20, and the protective film 50 covers the outer surface of the shell 211.

[0128] Optionally, the shell 211 forms a cavity for accommodating the electrode assembly. Depending on the structural shape of the battery cell 20, when it is a square-shell battery, the shell 211 includes four side walls and a first wall 21a in addition to the cover plate 212, and the protective film 50 covers the five walls in addition to the cover plate 212. When it is a cylindrical battery, the shell 211 may include the cylindrical peripheral wall, or it may include the cylindrical peripheral wall and a bottom wall. The pressure relief mechanism 213 is provided on the shell 211 covered by the protective film 50. The covering may completely cover the outer surface of the shell 211, or it may cover a portion of the outer surface of the shell 211.

[0129] As an implementation, because the thickness of the housing 211 is thinner than that of the cover plate 212, it is more susceptible to deformation due to gas generation within the battery cell 20. When the pressure relief mechanism 213 is disposed on the first wall 21a and / or sidewalls of the housing 211, deformation is also more likely to occur. The protective film 50 can limit deformation of the pressure relief mechanism 213, thereby extending its service life.

[0130] Alternatively, the pressure relief mechanism 213 in the embodiment of the present application may also be located on the cover plate 212. In this case, the same protective film 50 as that covering the shell 211 may be used to cover the entire outer surface of the cover plate 212 including the pressure relief mechanism 213, or may cover at least a portion of the outer surface of the cover plate 212 including the pressure relief mechanism 213.

[0131] As an implementation method, the area of ​​the first part 510 of the protective film 50 in the embodiment of the present application is larger than the area of ​​the area where the pressure relief mechanism 213 is located, and the area of ​​the first part 510 exceeding the pressure relief mechanism 213 is bonded to the outer surface of at least one wall.

[0132] like Figure 7b As shown, Figure 7b The dotted line portion in the middle of the oblong area is the edge of the pressure relief mechanism 213 covered by the protective film 50, and the solid line portion outside the pressure relief mechanism 213 is the edge of the first portion 510 of the protective film 50. The edge of the first portion 510 exceeds the edge of the pressure relief mechanism 213, that is, the area of ​​the first portion 510 is larger than the area of ​​the area where the pressure relief mechanism 213 is located. Among them, the portion of the first portion 510 that exceeds the pressure relief mechanism 213 can be fixedly connected to at least one wall of the battery cell 20, and the portion of the first portion 510 that is fixedly connected to at least one wall maintains the tension of the protective film 50, so that the protective film 50 has a certain rigidity. When the pressure relief mechanism 213 undergoes creep deformation or breathing deformation, the first portion 510 can use this rigidity to suppress the deformation of the pressure relief mechanism 213, reduce the amount of creep deformation of the pressure relief mechanism 213, and thus improve its service life.

[0133] It should be understood that the first part 510 of the protective film 50 in the embodiment of the present application can limit the deformation caused by the pressure relief mechanism 213 to a certain extent. When the pressure inside the battery cell 20 reaches or exceeds the actuation threshold of the pressure relief mechanism 213, the pressure relief mechanism 213 is actuated and the first part 510 is also destroyed, thereby ensuring the normal operation of the pressure relief mechanism 213 and the safety performance of the battery.

[0134] Specifically, for example, when the battery cell 20 is in normal use, the air pressure inside the battery cell 20 generally does not exceed 0.5 MPa. During normal use, the first part 510 can suppress the deformation of the pressure relief mechanism 213, but when the internal air pressure exceeds 0.5 MPa, the deformation of the pressure relief mechanism 213 is too large, and the first part 510 can be flushed away from the surface of at least one wall, thereby being actuated normally and releasing the internal pressure.

[0135] As an implementation manner, the first portion 510 of the protective film 50 in the embodiment of the present application has a shape that is the same as or similar to that of the pressure relief mechanism 213 .

[0136] like Figure 7b As shown, the first part 510 and the pressure relief mechanism 213 have the same shape. Setting the two to have the same shape can make the tension generated by the deformation of the pressure relief mechanism 213 on the first part 510 uniform, which is more conducive to the first part 510 suppressing the deformation of the pressure relief mechanism 213. Alternatively, the two can also use similar shapes, or different shapes, such as rectangles, etc., and the embodiments of the present application do not limit this.

[0137] As an implementation manner, in the embodiment of the present application, the distance T that the edge of the first portion 510 exceeds the edge of the pressure relief mechanism 213 in the direction away from the center of the pressure relief mechanism 213 is 6 mm to 10 mm.

[0138] like Figure 7b As shown, the distance between the edge of the first portion 510 (i.e., the solid line portion in the middle) and the edge of the pressure relief mechanism 213 (i.e., the dashed line portion in the middle) can be set to 6 mm to 10 mm. Because the portion of the first portion 510 that extends beyond the edge of the pressure relief mechanism 213 is bonded to at least one wall of the battery cell 20, there is a certain degree of constraint between the two. By adjusting the distance between the edge of the first portion 510 and the edge of the pressure relief mechanism 213, the constraint between the first portion 510 and at least one wall of the battery cell 20 can be adjusted, thereby ensuring that the first portion 510 can suppress deformation of the pressure relief mechanism 213 during normal use of the battery cell 20. Alternatively, when the area of ​​the pressure relief mechanism 213 is large and subject to significant creep deformation, a larger distance T is required to generate a constraint against the large deformation. However, when the area of ​​the pressure relief mechanism 213 is small, a smaller distance T can be set. When the pressure and temperature inside the battery cell 20 reach a certain threshold and the internal pressure needs to be released, the setting of the distance T can allow the first part 510 to be flushed open by the pressure relief mechanism 213 and fall off from at least one wall of the battery cell 20 without affecting the normal use of the pressure relief mechanism 213, thereby ensuring the safety of the battery.

[0139] For example, the edge of the first part 510 can be set to 6 mm beyond the edge of the pressure relief mechanism 213. When the battery cell 20 is in normal use, its internal pressure is generally not greater than 0.5 MPa. At this time, the restraint force between the first part 510 and at least one wall is large enough to ensure that it is not flushed open by the pressure relief mechanism 213 and falls off. When the pressure inside the battery cell 20 is greater than 0.5 MPa, the deformation of the pressure relief mechanism 213 can cause the first part 510 to fall off from at least one wall.

[0140] It should be understood that the above description is merely an exemplary description of the relationship between the shedding of the first portion 510 and the internal pressure of the battery cell 20 , wherein the pressure magnitude and the set size may also be set to other values, and the embodiment of the present application does not limit this.

[0141] As an implementation method, the protective film 50 in the embodiment of the present application can be made of polyester resin (Polyethyleneterephthalat, PET) or polypropylene PP material. The protective film 50 can also be a blue film commonly used in the battery field, or optionally, the protective film 50 in the embodiment of the present application can also be made of other materials, and the embodiment of the present application is not limited to this.

[0142] As an implementation method, the protective film in the embodiment of the present application may also include an isolation area 530 and a second part 520, the first part 510 is separated from the second part 520 by the isolation area 530, and the second part 520 covers the outer surface of at least one wall except the area covered by the first part 510.

[0143] like Figures 7a to 7c As shown, the protective film 50 may include a first portion 510 and a second portion 520, wherein the first portion 510 and the second portion 520 are separated by an isolation region 530, and the first portion 510 at least covers the outer surface of the pressure relief mechanism 213 provided on at least one wall, and the second portion 520 covers the outer surface of at least one wall except that covered by the first portion 510. Optionally, the second portion 520 may cover all the walls of the battery cell 20 except the area covered by the first portion 510, that is, the second portion 520 may cover all the outer surfaces of the peripheral wall and the top cover except those covered by the first portion 510, or the second portion 520 may only cover a portion thereof, such as only covering the outer surface of one wall including the pressure relief mechanism 213 except that covered by the first portion 510, for example Figures 7a to 7c The first wall 21a in the.

[0144] Alternatively, the isolation region 530 in the embodiment of the present application may be a linear region including the missing portion of the protective film 50, such as Figure 7c As shown, the isolation region 530 includes a portion between the first portion 510 and the second portion 520 of the protective film 50 where a portion of the material of the protective film 50 is missing, that is, the two portions are separated in terms of material. Figures 7a to 7c The linear isolation area 530 shown in the figure may also be an isolation zone with a relatively wide width, and this application does not limit this.

[0145] As an implementation manner, the isolation area 530 in the embodiment of the present application can be set around the outer edge of the pressure relief mechanism 213.

[0146] like Figure 7b As shown, the isolation region 530 is provided around the edge of the pressure relief mechanism 213 to form a first portion 510 covering at least the pressure relief mechanism 213 and a second portion 520 covering the outer surface except for the area covered by the first portion 510 .

[0147] As an implementation manner, the isolation region 530 in the embodiment of the present application may be continuous, and the first portion 510 is not connected to the second portion 520 .

[0148] Specifically, if Figure 7b As shown, the isolation region 530 is a continuous annular shape, and the first portion 510 and the second portion 520 can be completely separated by the isolation region 530, that is, there is no connection point between the first portion 510 and the second portion 520. At this time, because the first portion 510 is partially bonded to the surface of at least one wall, the restraining force between the partially bonded areas can ensure that the first portion 510 inhibits the deformation of the pressure relief mechanism 213, thereby inhibiting its creep and improving the service life of the pressure relief mechanism 213. At the same time, when the internal pressure and temperature of the pressure relief mechanism 213 reach a certain threshold, the first portion 510 can be broken open, causing the first portion 510 to fall off the surface of at least one wall, thereby allowing the pressure relief mechanism 213 to actuate normally, discharge internal emissions, and ensure safe use of the battery.

[0149] It should be understood that when the isolation area 530 in the embodiment of the present application is continuous and has no connection points, the area of ​​the first part 510 of the protective film 50 in the embodiment of the present application can be larger than the area of ​​the area where the pressure relief mechanism 213 is located, so as to ensure that a partial area of ​​the first part 510 can be bonded to the surface of at least one wall, thereby generating a restraining force that can suppress the deformation of the pressure relief mechanism 213.

[0150] As another implementation, the isolation region 530 in the embodiment of the present application may be non-continuous, and a connection point 540 is provided between the first portion 510 and the second portion 520 , and the first portion 510 and the second portion 520 are connected via the connection point 540 .

[0151] Specifically, Figure 8 FIG. 1 shows a schematic plan view of a non-contiguous isolation area in an embodiment of the present application. Figure 8 As shown, the isolation region 530 is further provided with a connection point 540, that is, the first portion 510 and the second portion 520 can be connected via the connection point 540, and the first portion 510 and the second portion 520 are not completely separated. The second portion 520 can constrain and transmit force to the first portion 510 via the connection point 540, and in this case, the edge area of ​​the first portion 510 can be set to be correspondingly smaller.

[0152] As an implementation manner, the number of connection points 540 in the embodiment of the present application may be positively correlated with the size of the edge of the first portion 510 extending beyond the edge of the pressure relief mechanism 213 in a direction away from the center of the pressure relief mechanism 213 .

[0153] As can be seen from the above, the bonded portion between the first portion 510 of the protective film 50 and at least one wall of the battery cell 20 can generate a restraining force to suppress deformation of the pressure relief mechanism 213. Within a certain range, the greater the distance the edge of the first portion 510 extends beyond the edge of the pressure relief mechanism 213 in the direction away from the center of the pressure relief mechanism 213, the greater the adhesive force generated between the two. When a connection point 540 is provided on the isolation region 530, since the connection point 540 connects the first portion 510 and the second portion 520, the second portion 520 can exert a restraining force on the first portion 510. The second portion 520, covering the other portion of the at least one housing, closely adheres to the housing and exerts a strong restraining force. Therefore, the provision of the connection point 540 can enhance the restraining force of the first portion 510 by leveraging the adhesive force, such as the fixing force, between the second portion 520 and the at least one wall, thereby reducing the area of ​​the first portion 510. Within a certain range, the greater the number of connection points 540, the greater the restraining force generated by the presence of the connection points 540. Therefore, the number of connection points 540 can be set to be related to the area of ​​the aforementioned bonding portion. That is, the greater the extent to which the edge of the first portion 510 extends beyond the edge of the pressure relief mechanism 213 in a direction away from the center of the pressure relief mechanism 213, the fewer the number of connection points 540 provided. Conversely, the smaller the aforementioned extent, the greater the number of connection points 540 provided. In this way, the restraining force generated by the portion where the first portion 510 is bonded to the surface of at least one wall and the restraining force generated by the presence of the connection points 540 can jointly suppress deformation of the pressure relief mechanism 213. At the same time, when the internal pressure and temperature of the pressure relief mechanism 213 reach a certain threshold, the first portion 510 can be dislodged and removed, thereby ensuring normal actuation of the pressure relief mechanism 213.

[0154] As an implementation manner, the battery cell 20 in the embodiment of the present application includes two electrode terminals 214 with opposite polarities, and at least two connection points 540 are provided along the connection direction of the two electrode terminals 214 .

[0155] like Figure 8 As shown, the battery cell 20 includes two electrode terminals 214, which may include a positive terminal and a negative terminal. When the pressure relief mechanism 213 is in accordance with Figure 8 The arrangement is shown in the manner shown, that is, corresponding to the situation where the pressure relief mechanism 213 is located on the first wall 21a or the cover plate 212, the long diameter direction of the oblong pressure relief mechanism 213 is parallel to the direction of the connection line of the two electrode terminals 214. When the pressure relief mechanism 213 is deformed, the position of the maximum deformation is in the direction of the connection line of the two electrode terminals 214. Corresponding to the first part 510, in order to better suppress the deformation of the pressure relief mechanism 213, the connection point 540 can be set as follows according to the deformation characteristics of the pressure relief mechanism 213. Figure 8The straight line portion shown is located in the isolation region 530 and is parallel to the line connecting the two electrode terminals.

[0156] Optionally, the pressure relief mechanism 213 in the embodiment of the present application may not be in accordance with Figure 8 Taking the pressure relief mechanism 213 as an example, the pressure relief mechanism 213 can also be arranged in such a way that the major diameter direction is perpendicular to the direction of the line connecting the two electrode terminals 214. In this case, the location of the connection point 540 can also be set according to the above principle, that is, the connection point 540 is set in an area of ​​the isolation region 530 parallel to the direction of the line connecting the two electrode terminals 214. In other words, the location of the connection point 540 in the embodiment of the present application is directly related to the direction of the line connecting the electrode terminals, and has no direct relationship with the shape and arrangement of the pressure relief mechanism 213.

[0157] As an implementation manner, the embodiment of the present application may further set a connection point 540 at other locations of the isolation area 530 .

[0158] Figure 9 FIG. 1 shows another schematic diagram of a non-contiguous isolation region according to an embodiment of the present application. Figure 9 As shown, the connection points 540 can also be provided on the curved portion of the isolation region 530 to enhance the first portion 510's ability to suppress deformation of the pressure relief mechanism 213. In the embodiment of the present application, the isolation region 530 can include multiple connection points 540. The multiple connection points 540 can be distributed at equal intervals, such as at equal angles or with equal arc lengths, or at non-equal intervals. The embodiment of the present application does not limit the number or location of the connection points 540.

[0159] In the above description, the area of ​​the first part 510 is larger than the area of ​​the pressure relief mechanism 213. Optionally, when a connection point 540 is provided on the isolation area 530, the edge of the first part 510 may coincide with the edge of the pressure relief mechanism 213.

[0160] Specifically, Figure 10 FIG. 1 shows another schematic diagram of a non-contiguous isolation region in an embodiment of the present application. Figure 10 As shown, since the edge of the first portion 510 coincides with the edge of the pressure relief mechanism 213, Figure 10 Only the edge of the first portion 510 is marked. Figure 10 FIG shows another embodiment of the distribution structure of the connection points 540, that is, the line connecting the connection points 540 and the center of the oblong circle can also be set to a region that forms a predetermined angle with the line connecting the two electrode terminals. The predetermined angle can be, for example, within the range of 0 degrees to 90 degrees, so as to adjust the number of connection points 540 to adapt to the change in the area of ​​the first part 510. It should be understood that this application Figures 8-12The arrangement of the connection points 540 shown does not strictly correspond to the structure of the first part 510 in the corresponding figure. Figures 8-12 The possible configuration of the connection point 540 is merely shown by way of example and is not intended to be limiting.

[0161] It should be understood that the pressure relief mechanism 213 of the embodiment of the present application can be provided on one of the walls of the housing 211, such as the first wall 21a as described above. Figures 8 to 10 As shown in , alternatively, the pressure relief mechanism in the embodiment of the present application may also be provided on the side wall of the housing 211 , but the present application is not limited thereto.

[0162] Specifically, Figure 11 FIG2 shows a schematic plan view of a protective film according to an embodiment of the present application. The protective film 50 can be used when the pressure relief mechanism 213 is disposed on any wall of the housing 211, such as a side wall or a bottom wall. In this case, the protective film 50 does not need to have openings corresponding to the electrode terminals 214. The remaining details are the same as those for the case where the pressure relief mechanism 213 is located on the first wall 21a, and will not be further described here.

[0163] Optionally, since the cover plate 212 and the housing 211 of the battery cell 20 are usually two separate parts, when the pressure relief mechanism 213 is provided on the cover plate 212, the second portion 520 of the protective film 50 may further include an area for accommodating the electrode terminal 214. Specifically, Figure 12 A schematic plan view of a protective film 50 according to an embodiment of the present application is shown, as shown in FIG. Figure 12 As shown, the protection film 50 may further include an opening 550 for accommodating the electrode terminal 214 .

[0164] As an implementation manner, the protective film 50 in the embodiment of the present application may be a patch, and the protective film 50 is bonded to the outer surface of the at least one wall by an adhesive.

[0165] For example, the protective film 50 can be a plastic patch, or also called a blue film, such as a plastic patch made of polyester resin or polypropylene material, and the patch can be bonded to the outer surface of at least one wall including the pressure relief mechanism by an adhesive.

[0166] Optionally, the protective film 50 in the embodiment of the present application can be bonded to the outer surface of at least one wall by means of an adhesive, or can be fixed to the outer surface of at least one wall by other means, and the present application does not impose any restrictions on this.

[0167] When the protective film 50 in the embodiment of the present application is a plastic patch, since the plastic patch is pasted on the outer surface of at least one wall of the battery cell 20, there may be a certain gap between the protective film 50 and the pressure relief mechanism 213, that is, the first part 510 and the pressure relief mechanism 213 are spaced apart. When there is a gap between the two, the pressure relief mechanism 213 may deform to a certain extent within the space allowed by the gap. Once the deformation of the pressure relief mechanism 213 exceeds the distance of the gap in the thickness direction of the shell 211, the first part 510 suppresses its deformation, reduces the deformation of the pressure relief mechanism caused by the breathing deformation of the shell, and suppresses creep deformation, thereby avoiding the failure of the pressure relief mechanism 213 caused by these two deformations.

[0168] Specifically, the first portion 510 of the protective film 50 can utilize the restraining force generated by the bonding and / or connection point 540 with at least one wall to suppress the deformation of the pressure relief mechanism 213 within a certain degree, reduce the creep of the pressure relief mechanism 213, and thus improve its service life.

[0169] Optionally, when the protective film 50 in the embodiment of the present application adopts the above-mentioned patch method, the isolation area 530 can be formed by laser ablation of the protective film 50.

[0170] Specifically, the patch can be first covered on at least one wall of the battery cell 20. At this time, the patch is a complete whole. Then, an isolation area 530 is formed on the patch through a laser cutting process, thereby dividing the protective film 50 into a first part 510 and a second part 520.

[0171] By using a laser ablation process to obtain the isolation region 530 in the embodiment of the present application, a first portion 510 for suppressing deformation of the pressure relief mechanism 213 can be formed on the basis of the protective film 50. On the one hand, the shape and size of the protective film 50 can be adjusted in real time by controlling the motion trajectory of the laser head and the ablation power, without the need for repeated mold opening, thereby reducing processing costs. On the other hand, the processed protective film 50 can insulate and protect the battery cell 20. For example, during the injection process during the production of the battery cell 20, it can effectively prevent the electrolyte from contacting the pressure relief mechanism 213, thereby protecting the pressure relief mechanism 213 and suppressing deformation of the pressure relief mechanism 213 to a certain extent, thereby increasing its service life.

[0172] As another implementation manner, the protective film 50 in the embodiment of the present application may also be a coating, and the protective film 50 is applied to the outer surface of the at least one wall and the pressure relief mechanism 213 by spraying.

[0173] When the protective film 50 is a coating, the isolation region 530 may be formed by leaving a portion of the protective film 50 uncoated when the protective film 50 is applied to the surface of the at least one wall and the pressure relief mechanism 213. For example, a template may be pre-placed at the location where the isolation region 530 is to prevent the coating from being sprayed onto the location of the isolation region 530.

[0174] Optionally, when the protective film 50 adopts a coating, the coating can be directly covered on the surface of the pressure relief mechanism 213. Since the coating with a thicker thickness can have a greater restraining effect on the deformation of the pressure relief mechanism 213, at this time, the coating thickness of the first part 510 can be set to be greater than the coating thickness of the second part 520 to achieve a better effect of suppressing the deformation of the pressure relief mechanism 213.

[0175] Optionally, when the protective film 50 in the embodiment of the present application adopts a coating, since the first part 510 and the pressure relief mechanism 213 are bonded to each other, there is a certain constraint between the two. The edge of the first part 510 can coincide with the edge of the pressure relief mechanism 213, or, according to the above embodiment, the edge of the first part 510 can be set to extend beyond the edge of the pressure relief mechanism 213. Furthermore, a connection point 540 can be set on the isolation area 530. The embodiment of the present application does not limit the specific implementation method.

[0176] As an implementation, the battery 10 in the embodiment of the present application may include a plurality of battery cells, including at least one battery cell 20 in the aforementioned embodiments, wherein the plurality of battery cells 20 may be insulated from each other by a protective film 50 .

[0177] One embodiment of the present application further provides an electric device, which may include the battery 10 in the aforementioned embodiments. Optionally, the electric device may be a vehicle 1, a ship, or a spacecraft.

[0178] The above describes the battery cells, batteries and electrical devices of the embodiments of the present application. The following describes the method and device for preparing the battery of the embodiments of the present application. For the parts not described in detail, please refer to the aforementioned embodiments.

[0179] Figure 13 FIG. 3 is a schematic flow chart of a method 300 for preparing a battery cell according to an embodiment of the present application. Figure 13 As shown, the method 300 may include:

[0180] S310 , providing a pressure relief mechanism 213 on at least one wall of the battery cell 20 .

[0181] As an implementation manner, the pressure relief mechanism 213 is configured to be activated to release the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value.

[0182] S320 , coating the outer surface of the at least one wall with a protective film 50 , wherein the protective film 50 is used to provide insulation protection for the at least one wall.

[0183] As an implementation, the protective film 50 includes a first portion, and the first portion at least covers the pressure relief mechanism 213 .

[0184] Figure 14 FIG. 4 is a schematic block diagram of an apparatus 400 for preparing a battery cell according to an embodiment of the present application. Figure 14 As shown, the battery manufacturing apparatus 400 may include: a setting module 410 .

[0185] A module 410 is provided for providing a pressure relief mechanism 213 on at least one wall of the battery cell 20, wherein the pressure relief mechanism 213 is configured to be actuated to release the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value; a protective film 50 is covered on the outer surface of the at least one wall, wherein the protective film 50 is configured to provide insulating protection for the at least one wall; wherein the protective film 50 includes a first portion 510, and the first portion at least covers the pressure relief mechanism 213.

[0186] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: a pressure relief mechanism, the pressure relief mechanism being disposed on at least one wall of the battery cell, the pressure relief mechanism being configured to be actuated to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold; a protective film covering an outer surface of the at least one wall, wherein the protective film is used to provide insulation protection for the at least one wall; In which, the protective film includes a first part, the first part covers at least the pressure relief mechanism, the area of ​​the first part is larger than the area of ​​the region where the pressure relief mechanism is located, and the region of the first part exceeding the pressure relief mechanism is adhered to the outer surface of the at least one wall, the protective film also includes an isolation region and a second part, the second part covers the outer surface of the at least one wall except the region covered by the first part, the portion between the first part and the second part where the protective film is missing forms the isolation region, and the isolation region is used to separate the first part and the second part.

2. The battery cell according to claim 1, wherein: The shape of the first portion is the same as or similar to that of the pressure relief mechanism.

3. The battery cell according to claim 1, wherein: The edge of the first portion extends beyond the edge of the pressure relief mechanism by 6 mm to 10 mm in a direction away from the center of the pressure relief mechanism.

4. The battery cell according to claim 1, wherein: At least one wall of the battery cell includes a shell, the shell forming an accommodation cavity with an opening for accommodating the electrode assembly of the battery cell, and the protection film covers an outer surface of the shell.

5. The battery cell according to claim 1, characterized in that The isolation area is disposed around an outer edge of the pressure relief mechanism.

6. The battery cell according to claim 1, characterized in that The isolation region is continuous, and the first portion is not connected to the second portion.

7. The battery cell according to claim 1, characterized in that The isolation area is non-continuous, a connection point is provided between the first part and the second part, and the first part and the second part are connected through the connection point.

8. The battery cell according to claim 7, characterized in that The number of the connection points is directly proportional to the extent to which the edge of the first portion extends beyond the edge of the pressure relief mechanism in a direction away from the center of the pressure relief mechanism.

9. The battery cell according to claim 7, characterized in that: The battery cell includes two electrode terminals with opposite polarities, and at least two connection points are provided along a connection direction of the two electrode terminals.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The protective film is a patch, and the protective film is adhered to the outer surface of the at least one wall by an adhesive.

11. The battery cell according to claim 10, characterized in that The isolation region is formed by laser ablation of the protection film.

12. The battery cell according to any one of claims 1 to 9, characterized in that: The protective film is a coating, and the protective film is applied to the outer surface of the at least one wall and the pressure relief mechanism by spraying.

13. The battery cell according to claim 12, characterized in that: The isolation area is formed by reserving a portion of the area for non-coating when coating the protective film on the surface of the at least one wall and the pressure relief mechanism.

14. The battery cell according to claim 12, characterized in that The thickness of the first portion is greater than the thickness of the second portion.

15. A battery, characterized in that: include: A plurality of battery cells, wherein the plurality of battery cells include at least one battery cell according to any one of claims 1 to 14; wherein the plurality of battery cells are insulated from each other by the protective film.

16. An electrical device, characterized in that: include: The battery according to claim 15.

17. A method for preparing a battery cell, characterized in that: include: A pressure relief mechanism is provided on at least one wall of the battery cell, wherein the pressure relief mechanism is configured to be actuated to release the internal pressure when the internal pressure or temperature of the battery cell reaches a threshold value; A protective film is coated on the outer surface of the at least one wall, wherein the protective film is used to provide insulation protection for the at least one wall; In which, the protective film includes a first part, the first part covers at least the pressure relief mechanism, the area of ​​the first part is larger than the area of ​​the region where the pressure relief mechanism is located, and the region of the first part exceeding the pressure relief mechanism is adhered to the outer surface of the at least one wall, the protective film also includes an isolation region and a second part, the second part covers the outer surface of the at least one wall except the region covered by the first part, the portion between the first part and the second part where the protective film is missing forms the isolation region, and the isolation region is used to separate the first part and the second part.

18. The method according to claim 17, characterized in that The shape of the first portion is set to be the same as or similar to the shape of the pressure relief mechanism.

19. The method according to claim 17, wherein The edge of the first portion is arranged to extend beyond the edge of the pressure relief mechanism by 6 mm to 10 mm in a direction away from the center of the pressure relief mechanism.

20. The method according to claim 17, wherein At least one wall of the battery cell includes a shell, the shell forms an accommodation cavity with an opening for accommodating the electrode assembly of the battery cell, and the protection film is coated on an outer surface of the shell.

21. The method according to claim 17, wherein The isolation area is disposed around an outer edge of the pressure relief mechanism.

22. The method according to claim 17, wherein The isolation region is continuous, and the first portion is not connected to the second portion.

23. The method according to claim 17, wherein A connection point is provided between the first portion and the second portion to form the non-contiguous isolation region, and the first portion and the second portion are connected via the connection point.

24. The method according to claim 23, wherein The number of the connection points is directly proportional to the extent to which the edge of the first portion extends beyond the edge of the pressure relief mechanism in a direction away from the center of the pressure relief mechanism.

25. The method according to claim 23, characterized in that The battery cell includes two electrode terminals with opposite polarities, and at least two connection points are provided along a connection direction of the two electrode terminals.

26. The method according to any one of claims 17 to 25, characterized in that The protective film is a patch, and the protective film coated on the outer surface of the at least one wall includes: The protective film is bonded to the outer surface of the at least one wall by an adhesive.

27. The method according to claim 26, characterized in that After the protective film is bonded to the outer surface of the at least one wall by an adhesive, the protective film is ablated by laser to form the isolation area.

28. The method according to any one of claims 17 to 25, characterized in that The protective film is a coating, and the protective film coated on the outer surface of the at least one wall comprises: The protective film is applied to the outer surface of the at least one wall and the pressure relief mechanism by spraying.

29. The method according to claim 28, characterized in that The protective film applied to the outer surface of the at least one wall further comprises: When the protective film is coated on the outer surface of the at least one wall and the pressure relief mechanism, some areas are reserved for not being coated to form the isolation area.

30. The method according to claim 28, wherein The coating thickness of the first portion is set to be greater than the coating thickness of the second portion.

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