Battery cell, battery, and electric device

Abstract

A battery monomer, a battery and a power consuming device, capable of reducing the influence on the surface of the shell of the battery monomer in the forming process of the pressure relief notch. The battery monomer comprises a first wall and a second wall perpendicular to the first wall, the first wall is integrally formed with a pressure relief notch, the area between the pressure relief notch and the second wall on the first wall is provided with an isolation groove, and the pressure relief notch comprises a main body part, the main body part is opposite to the isolation groove in the direction perpendicular to the second wall, wherein the ratio between the distance between the main body part and the second wall in the direction perpendicular to the second wall and the size of the main body part is greater than or equal to 10.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. Batteries consist of individual cells, each with pressure relief grooves to release internal pressure. How to minimize the impact of these pressure relief grooves on other parts of the battery cell is a pressing issue that needs to be addressed. Summary of the Invention

[0003] This application provides a battery cell, a battery, and an electrical device that can reduce the impact on the surface of the battery cell casing during the formation of pressure relief marks.

[0004] In a first aspect, a battery cell is provided, the battery cell including a first wall and a second wall perpendicular to the first wall, the first wall having an integrally formed pressure relief groove, and an isolation groove being provided in the area between the pressure relief groove and the second wall on the first wall, the pressure relief groove including a main body portion, the main body portion being opposite to the isolation groove in a direction perpendicular to the second wall.

[0005] Wherein, in the direction perpendicular to the second wall, the ratio between the distance between the main body and the second wall and the size of the main body is greater than or equal to 10; preferably, in the direction perpendicular to the second wall, the ratio between the distance between the main body and the second wall and the size of the main body is greater than or equal to 12.

[0006] During the process of stamping pressure relief marks on the first wall of a battery cell, the extruded material flows to the vicinity of the marks. During the formation of the casing through processes such as fine drawing, this material may accumulate on the second wall, which is perpendicular to the first wall, causing defects on the casing surface and affecting its flatness. In this application, an isolation groove is provided on the first wall of the battery cell where the pressure relief marks are formed. This groove is located between the pressure relief marks and the second wall, allowing it to accommodate the material extruded during the process of forming the pressure relief marks on the first wall. In subsequent processes, this prevents the material from flowing to the second wall, reducing the impact on the casing surface of the battery cell during the formation of the pressure relief marks.

[0007] In some possible implementations, the opening of the isolation groove faces the same direction as the opening of the pressure relief groove. This allows the material extruded during the process of creating the pressure relief groove on the first wall to be promptly blocked by the isolation groove.

[0008] In some possible implementation manners, the number of the isolation grooves is multiple, and the multiple isolation grooves are arranged on both sides of the pressure relief indentation along a direction perpendicular to the second wall. By arranging the isolation grooves on both sides of the pressure relief indentation respectively, the materials extruded from both sides of the pressure relief indentation can be blocked by the isolation grooves on both sides.

[0009] In some possible implementation manners, the second wall is the wall with the largest area of the battery cell, and is also referred to as the "large wall". Since the manufacturing process of the pressure relief indentation has the greatest impact on the large wall of the battery cell, arranging the isolation groove between the pressure relief indentation and the large wall is beneficial to reducing the impact on the large wall of the battery cell.

[0010] In some possible implementation manners, the projection of the pressure relief indentation on the first wall includes a main body portion extending along a first direction, and two extension portions respectively located at two ends of the main body portion and extending along a second direction. For example, the extension portion is located on one side of the main body portion in the second direction; or, the extension portions are located on both sides of the main body portion in the second direction.

[0011] Wherein, the first direction intersects with the second direction. For example, the first direction is parallel to the second wall, and the second direction is perpendicular to the second wall.

[0012] In this implementation manner, the pressure relief indentation can be in a shape similar to a "work" character or an unclosed "square" character, including a main body portion extending along the first direction and two extension portions respectively located at two ends of the main body portion and extending along the second direction, so that the pressure inside the battery cell can be released to the outside simultaneously along the first direction and the second direction, improving the detonation uniformity of the pressure relief indentation, and further improving the stability of the pressure relief indentation.

[0013] In some possible implementation manners, the projection of the isolation groove on the side where the extension portion is located on the first wall is located between the two extension portions in the first direction and does not exceed the ends of the two extension portions in the second direction. Since the position between the two extension portions of the pressure relief indentation is where materials are likely to accumulate during the manufacturing process of the pressure relief indentation, arranging the isolation groove between the two extension portions enables the isolation groove to accommodate more extruded materials, which is beneficial to reducing the impact of the materials on the surface of the battery cell housing in subsequent processes.

[0014] In some possible implementation manners, the dimension of the main body portion along the first direction is equal to the sum of the dimensions of the two extension portions along the second direction. This makes the lengths of the pressure release paths in the first direction and the second direction the same, and the pressure borne by the pressure relief indentation is more uniform, improving the stability of the pressure relief indentation.

[0015] In some possible implementations, the projection of the pressure relief groove onto the first wall is annular. Using annular pressure relief grooves allows the pressure inside the battery cell to be released in all directions, improving the uniformity of the pressure relief groove's initiation and thus enhancing its stability.

[0016] In some possible implementations, the projection of the isolation groove onto the first wall is an annular ring surrounding the pressure relief groove. Since the material extruded during the creation of the annular pressure relief groove overflows in all directions, setting the isolation groove to an annular shape surrounding the pressure relief groove effectively blocks the material overflowing from all directions.

[0017] In some possible implementations, the thickness of the region containing the isolation groove on the first wall is greater than the thickness of the region containing the pressure relief groove on the first wall. To ensure the pressure relief function of the pressure relief groove is not affected, the depth of the isolation groove should be less than the depth of the pressure relief groove; that is, the thickness of the region containing the isolation groove on the first wall is greater than the thickness of the region containing the pressure relief groove.

[0018] In some possible implementations, the thickness of the region containing the isolation groove on the first wall is greater than or equal to the thickness of the region containing the pressure relief mark on the first wall, and less than or equal to five times the thickness of the region containing the pressure relief mark on the first wall; preferably, the thickness of the region containing the isolation groove on the first wall is greater than or equal to twice the thickness of the region containing the pressure relief mark on the first wall, and less than or equal to three times the thickness of the region containing the pressure relief mark on the first wall. When the thickness of the region containing the isolation groove on the first wall and the thickness of the region containing the pressure relief mark satisfy the above relationship, the impact of the isolation groove on the pressure relief function of the pressure relief mark can be reduced, without affecting the isolation capability of the isolation groove for extruded material.

[0019] In some possible implementations, in a direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the second wall is greater than or equal to the size of the isolation groove; preferably, in a direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the second wall is greater than or equal to three times the size of the isolation groove.

[0020] When the distance between the isolation groove and the second wall satisfies the above relationship, the material extruded during the process of making the isolation groove itself on the first wall is less likely to flow to the second wall, thereby reducing the impact of the material extruded during the manufacturing process of the isolation groove on the second wall in subsequent processes.

[0021] In some possible implementations, in the direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the pressure relief mark is greater than or equal to the size of the isolation groove; preferably, in the direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the pressure relief mark is greater than or equal to three times the size of the isolation groove.

[0022] When the distance between the isolation groove and the pressure relief groove satisfies the above relationship, the influence on the groove morphology of the pressure relief groove during the fabrication of the isolation groove can be reduced, thereby reducing the impact on the burst pressure of the pressure relief groove.

[0023] In some possible implementations, the pressure relief groove includes a multi-step structure. During the fabrication of the pressure relief groove, the corresponding position on the first wall can be punched multiple times, with each punch forming a step. The pressure relief groove is obtained through multiple forming processes. The staged forming of the pressure relief groove can reduce the particle size of the extruded material and reduce the impact on the surface of the battery cell casing.

[0024] In some possible implementations, the battery cell includes an electrode assembly, a housing, and an end cap. The housing houses the electrode assembly, and the end cap covers the electrode assembly within the housing. The first wall is a wall on the housing opposite the end cap, such as the bottom wall; that is, pressure relief markings can be provided on the bottom wall of the housing. Thus, after stamping an integral pressure relief marking on the first wall, a housing with the pressure relief marking can be formed through a fine drawing process. Since an isolation groove is also provided on the first wall, the extruded material can be contained within this groove, preventing it from accumulating on the housing surface after the fine drawing process and reducing the probability of defects such as protrusions on the housing surface.

[0025] In a second aspect, a battery is provided, comprising the battery cell described in the first aspect or any possible implementation thereof.

[0026] Thirdly, an electrical device is provided, comprising the battery described in the second aspect or any possible implementation thereof, the battery being used to provide electrical energy to the electrical device. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0028] Figure 1 This is a structural schematic diagram of the vehicle according to an embodiment of this application.

[0029] Figure 2 This is a schematic diagram of the battery structure according to an embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the structure of a battery cell according to an embodiment of this application.

[0031] Figure 4 This is a side view of a pressure relief groove and isolation groove according to an embodiment of this application.

[0032] Figure 5 This is a top view schematic diagram of the pressure relief groove and isolation groove according to an embodiment of this application.

[0033] Figure 6 This is a schematic diagram of a pressure relief groove and isolation groove according to another embodiment of this application.

[0034] Figure 7 This is a schematic diagram of a pressure relief groove and isolation groove according to another embodiment of this application.

[0035] Figure 8 This is a schematic diagram of a pressure relief groove and isolation groove according to another embodiment of this application.

[0036] Figure 9 This is a schematic diagram of a pressure relief groove and isolation groove according to another embodiment of this application.

[0037] Figure 10 This is a schematic diagram of the steps of the pressure relief groove in an embodiment of this application.

[0038] The accompanying drawings are not drawn to scale. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0041] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0043] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0044] In this application, "multiple" refers to two or more; similarly, "multiple groups" refers to two or more groups, and "multiple pieces" refers to two or more pieces.

[0045] In this embodiment, the battery cell can be a rechargeable battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. Examples of battery cells include lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., but this embodiment is not limited to these types.

[0046] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions, such as lithium ions, repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0047] In some embodiments, the positive electrode can be a positive electrode sheet, which includes a positive current collector and a positive active material disposed on at least one surface of the positive current collector.

[0048] The positive electrode current collector has two surfaces opposite each other in its own thickness direction, and the positive electrode active material is disposed on either or both of the two opposite surfaces of the positive electrode current collector.

[0049] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming metal materials such as aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys on a polymer material base material such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0050] The positive electrode active material includes, for example, at least one of the following: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. This application is not limited to these materials; other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate such as LiFePO4 (also abbreviated as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate such as LiMnPO4, lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites.

[0051] In some embodiments, the negative electrode may be a negative electrode sheet, which includes a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0052] The negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0053] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium, etc. Composite current collectors can include a polymer material substrate and a metal layer. Composite current collectors can be formed by forming metal materials such as copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys on a polymer material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0054] Among them, the negative electrode active material includes at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc.

[0055] In some embodiments, the negative electrode may also be a foamed metal. The foamed metal may be foamed nickel, foamed copper, foamed aluminum, foamed alloy, or foamed carbon, etc. It should be noted that when foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not have a negative electrode active material.

[0056] Optionally, the negative electrode current collector may also be filled with or / and deposited with lithium source material, potassium metal or sodium metal, the lithium source material including lithium metal and / or lithium-rich material.

[0057] The positive electrode current collector can be made of materials such as aluminum, and the negative electrode current collector can be made of materials such as copper.

[0058] A separator in the electrode assembly is disposed between the positive and negative electrodes. In some embodiments, the separator is a separator membrane. This application does not limit the type of separator membrane; any porous separator membrane with good chemical and mechanical stability can be selected. For example, the main material of the separator membrane can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0059] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0060] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not limit the type of electrolyte; it can be selected according to requirements. The electrolyte can be liquid, gel, or solid.

[0061] In this embodiment, the electrode assembly can be a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound to form the wound structure. The electrode assembly can also be a stacked structure; for example, multiple positive and negative electrode sheets can be configured, with multiple positive and multiple negative electrode sheets alternately stacked. Alternatively, multiple positive electrode sheets can be configured, and negative electrode sheets can be folded to form multiple stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments; or, both positive and negative electrode sheets can be folded to form multiple stacked folded segments.

[0062] Multiple separators can be configured and disposed between any adjacent positive and negative electrode plates.

[0063] In some embodiments, the separator can be continuously arranged and disposed between any adjacent positive and negative electrode sheets by means of folding or rolling.

[0064] The electrode assembly can be cylindrical, flat, or polygonal in shape, for example. The electrode assembly may have tabs, including positive and negative tabs, for conducting current from the electrode assembly.

[0065] In some embodiments, the battery cell includes a casing. The casing encapsulates components such as electrode assemblies and electrolytes. The casing can be made of steel, aluminum, plastic (e.g., polypropylene), composite metal (e.g., copper-aluminum composite), or aluminum-plastic film. The casing includes a housing and a cover.

[0066] The battery cell can be, for example, a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, or multi-prismatic batteries, among which multi-prismatic batteries can be hexagonal prismatic batteries, etc. This application does not limit this.

[0067] The battery described in the embodiments of this application may be a single physical module comprising one or more battery cells to provide higher voltage and capacity. In the case of multiple battery cells, the multiple battery cells are connected in series, parallel, or mixed via a busbar.

[0068] In some embodiments, the battery can be a battery module, where multiple battery cells are arranged and fixed to form a battery module.

[0069] In some embodiments, the battery can be a battery pack, which includes a housing and individual battery cells, with the individual battery cells or battery modules housed within the housing.

[0070] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0071] For batteries, the main safety hazards arise during the charging and discharging processes. To improve battery safety, pressure relief mechanisms are typically incorporated into individual battery cells. These mechanisms are, for example, elements or components that activate when the internal pressure or temperature of a battery cell reaches a predetermined threshold to release that pressure or temperature. This predetermined threshold can be adjusted according to the battery's design requirements. It may depend on one or more materials used in the positive electrode, negative electrode, electrolyte, and separator within the battery cell. Pressure relief mechanisms can employ pressure-sensitive or temperature-sensitive elements or components; that is, when the internal pressure or temperature of the battery cell reaches the threshold, the mechanism activates to create a channel for releasing internal pressure or temperature. After activation, the high-temperature, high-pressure substances inside the battery cell are discharged as waste from the mechanism to the outside of the cell. In this way, pressure relief can be achieved within the battery cell under controlled pressure or temperature conditions, thereby preventing potentially more serious accidents. The emissions from this battery cell include, but are not limited to, high-temperature and high-pressure gases generated during the reaction, electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, flames, etc.

[0072] For serrated pressure relief mechanisms, they are typically integrally formed onto the surface of the battery cell casing. In this embodiment, such pressure relief mechanisms are also referred to as pressure relief serrations. For example, the pressure relief serrations can be formed by stamping. During the stamping process, the extruded material flows to the vicinity of the pressure relief serrations. In the subsequent process of forming the casing through processes such as fine drawing, this material may accumulate on the surface of the battery cell casing, thereby causing defects on the casing surface and affecting its flatness.

[0073] In view of this, the present application aims to solve the problem of the material's impact on the housing surface by providing an isolation groove on the first wall of the battery cell used for setting pressure relief marks, so as to prevent the material extruded during the pressure relief mark making process from flowing to the housing surface.

[0074] The technical solutions described in the embodiments of this application are applicable to various battery-powered devices, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, electric vehicles, ships, and spacecraft. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft.

[0075] It should be understood that the technical solutions described in the embodiments of this application are not limited to the devices described above, but can also be applied to all devices that use batteries. However, for the sake of brevity, the following embodiments are all illustrated using electric vehicles as examples.

[0076] For example, such as Figure 1The diagram shown is a structural schematic of a vehicle 1 according to one embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A motor 300, a controller 200, and a battery 100 can be installed inside vehicle 1. The controller 200 controls the battery 100 to supply power to the motor 300. For example, the battery 100 can be installed at the bottom, front, or rear of vehicle 1. The battery 100 can be used to power vehicle 1. For example, the battery 100 can serve as the operating power source for vehicle 1, for example, for the electrical system of vehicle 1, such as for the power requirements of vehicle 1's starting, navigation, and operation. In another embodiment of this application, the battery 100 can not only serve as the operating power source for vehicle 1, but also as the driving power source for vehicle 1, replacing or partially replacing gasoline or natural gas to provide driving power for vehicle 1.

[0077] To meet diverse power demands, batteries can comprise multiple individual battery cells of varying types. These cells can be connected in series, parallel, or a combination thereof to form battery cell groups. These groups can then be connected in series to form a battery. A combination of series and parallel connections is a hybrid of both. Alternatively, multiple different battery cells can be directly connected in series, parallel, or a combination thereof to form a battery. In other words, multiple battery cells can be directly assembled into a battery, or they can first be grouped into battery cell groups according to their types, and then these groups can be combined to form a battery.

[0078] Figure 2 A schematic diagram of a battery 100 according to an embodiment of this application is shown. The battery 100 may include a plurality of battery cells 20. The battery 100 may also include a housing 10, which has a hollow interior structure, and the plurality of battery cells are housed within the housing 10. The housing 10 may include two parts, referred to herein as a first housing portion 11 and a second housing portion 12, which are fastened together. The shapes of the first housing portion 11 and the second housing portion 12 may be determined according to the shape of the combination of the plurality of battery cells, and at least one of the first housing portion 11 and the second housing portion 12 has an opening.

[0079] For example, such as Figure 2 As shown, both the first housing portion 11 and the second housing portion 12 are hollow structures with only one open side. The openings of the first housing portion 11 and the second housing portion 12 are arranged opposite to each other, and the first housing portion 11 and the second housing portion 12 are interlocked to form a housing 10 with a closed cavity. Multiple battery cells are connected in parallel, series, or mixed configurations and placed inside the housing 10 formed by the interlocking of the first housing portion 11 and the second housing portion 12.

[0080] For example, unlike Figure 2As shown, only one of the first housing portion 11 and the second housing portion 12 is a hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 12 as a hollow structure with only one open side and the first housing portion 11 as a plate-shaped example, the first housing portion 11 covers the opening of the second housing portion 12 to form a housing 10 with a closed chamber, which can be used to accommodate multiple battery cells. Multiple battery cells are connected in parallel, series, or mixed configurations and placed inside the housing 10 formed by the first housing portion 11 and the second housing portion 12.

[0081] In addition, the battery 100 may include other structures, such as a signal transmission assembly for transmitting signals such as the voltage and / or temperature of the battery cells. The signal transmission assembly may include a wiring harness board, which includes, for example, a temperature sensor and a voltage sampling line, for measuring and transmitting information such as the battery's voltage, current, and temperature, and for enabling the safe management of the battery 100 through communication with the BMS.

[0082] In some embodiments, the signal transmission component may further include a busbar for electrically connecting multiple battery cells, such as in parallel, series, or mixed connections. The busbar connects the battery cells by connecting their electrode terminals. In some embodiments, the busbar is fixed to the electrode terminals of the battery cells by welding. The busbar transmits the voltage of the battery cells; when multiple battery cells are connected in series, a higher voltage is obtained. Accordingly, the electrical connection formed by the busbar can also be referred to as a "high-voltage connection."

[0083] As an example, such as Figure 3 The schematic diagram shown below illustrates the structure of a single battery cell 20 according to an embodiment of this application. This is provided as an example. Figure 3 As shown, the battery cell 20 includes an electrode assembly 21, a housing 22, and an end cap 23. The housing 22 is used to house the electrode assembly 21, and the end cap 23 is used to cover the electrode assembly 21 inside the housing 22. The end cap 23 and the housing 22 can be connected, for example, by welding.

[0084] In this embodiment of the application, the battery cell 20 includes a first wall 221 and a second wall 222. The second wall 222 is perpendicular to the first wall 221. The first wall 221 is provided with a pressure relief groove 24. An isolation groove 25 is provided in the area between the pressure relief groove 24 and the second wall 222 on the first wall 221.

[0085] As an example, such as Figure 3As shown, the first wall 221 can be the wall on the housing 22 opposite to the end cap 23, i.e., the bottom wall of the housing 22. Optionally, the pressure relief mark 24 is formed on the first wall 221 by an integral molding process. For example, the pressure relief mark 24 can be formed by stamping on the first wall 221 using a punch press. During the stamping process, the material stamped out of the pressure relief mark 24 will flow to the surrounding area of ​​the pressure relief mark 24. During the process of forming the housing 22 by a precision drawing process, this material may accumulate on the surface of the housing 22, such as on the second wall 222 perpendicular to the first wall 221, causing surface defects of the housing 22, such as protrusions, and affecting the flatness of the surface of the housing 22.

[0086] The second wall 222 can be, for example, the wall with the largest area of ​​the battery cell 20, also known as the "large wall". Since the pressure relief mark 24 has the greatest impact on the large wall of the battery cell 20 during the manufacturing process, placing the isolation groove 25 between the pressure relief mark 24 and the large wall helps to reduce the impact on the large wall of the battery cell 20.

[0087] In this embodiment, an isolation groove 25 is provided on the first wall 221 of the battery cell 20 for setting the pressure relief groove 24. The isolation groove 25 is located between the pressure relief groove 24 and the second wall 222, so that the isolation groove 25 can accommodate the material extruded during the process of making the pressure relief groove 24 on the first wall 221, and prevent the material from flowing to the second wall 222 in subsequent processes, thereby reducing the impact on the surface of the casing 22 of the battery cell 20.

[0088] In some embodiments, the opening of the isolation groove 25 faces the same direction as the opening of the pressure relief groove 24. In this way, the material extruded during the process of making the pressure relief groove 24 on the first wall 221 can be blocked by the isolation groove 25 in a timely manner.

[0089] In some embodiments, there are multiple isolation grooves 25, which are arranged on both sides of the pressure relief groove 24 in a direction perpendicular to the second wall 222. In this way, the material extruded from both sides of the pressure relief groove 24 can be blocked by the isolation grooves 25 on both sides. For example, the multiple isolation grooves 25 can be symmetrically arranged on both sides of the pressure relief groove 24.

[0090] Optionally, the pressure relief groove 24 includes a main body 241, which is opposite to the isolation groove 25 in a direction perpendicular to the second wall 222. In this direction, the ratio between the distance between the main body 241 and the second wall 222 and the size of the main body 241 is greater than or equal to 10. Preferably, in the direction perpendicular to the second wall 222, the ratio between the distance between the main body 241 and the second wall 222 and the size of the main body 241 is greater than or equal to 12.

[0091] It is understandable that areas with a large amount of extruded material on the pressure relief notch 24, such as the main body 241, require special isolation. In the direction perpendicular to the second wall 222, if the distance between the main body 241 and the second wall 222 is too small, the extruded material corresponding to the main body 241 is more likely to flow to the second wall 222, causing surface defects on the second wall 222. In this case, a corresponding isolation groove 25 can be provided between the main body 241 and the second wall 222 to prevent the extruded material corresponding to the main body 241 from flowing to the second wall 222 in subsequent processes.

[0092] In the direction perpendicular to the second wall 222, the distance between the main body 241 and the second wall 222 is related to the size of the main body 241. When the distance between the main body 241 and the second wall 222 is large, the extruded material corresponding to the main body 241 has sufficient space to flow evenly without affecting the surface of the second wall 222, so the isolation groove 25 does not need to be provided between the main body 241 and the second wall 222. However, when the distance between the main body 241 and the second wall 222 is small, the extruded material corresponding to the main body 241 may flow to the surface of the second wall 222 in subsequent processes, thus affecting the second wall 222. The larger the size of the main body 241 in the direction perpendicular to the second wall 222, the more extruded material corresponds to the main body 241, and the larger the distance between the pressure relief mark 24 and the second wall 222 should be. Setting the ratio between the distance between the main body 241 and the second wall 222 and the size of the main body 241 to be greater than or equal to 10, preferably greater than or equal to 12, can effectively reduce the impact of the material extruded from the pressure relief groove 24 during the manufacturing process on the second wall 222.

[0093] In this embodiment of the application, the direction perpendicular to the second wall 222 may be a direction with an angle of 90° between it and the second wall 222. Alternatively, due to deviations caused by manufacturing processes, deformation during battery use, etc., the angle between this direction and the second wall 222 may not be strictly equal to 90°, but may be slightly less than or slightly greater than 90°.

[0094] As an example, such as Figure 4 and Figure 5 As shown, taking two isolation grooves 25 as an example, the two isolation grooves 25 are located on both sides of the pressure relief groove 24 along the second direction Y, which is perpendicular to the second wall 222. In the second direction Y, the ratio p between the distance p between the pressure relief groove 24 and the second wall 222 and the size b of the pressure relief groove 24 is p / b ≥ 10; preferably, p / b ≥ 12. It should be noted that for... Figure 4 and Figure 5 The rectangular pressure relief mark 24 shown has its main body 241 as the entire pressure relief mark 24.

[0095] As shown in Table 1, assuming the dimension b = 4 mm of the pressure relief notch 24 in the second direction Y, the thickness of the second wall 222 of the test housing 22 exceeds its standard wall thickness under the conditions of p / b = 2, p / b = 4, p / b = 6, p / b = 8, p / b = 10, p / b = 12, and p / b = 14, respectively; that is, the increase in thickness of the second wall 222. To improve the accuracy of the test results, four tests were performed, and the average value of the four tests can be used as the test result.

[0096] Table 1

[0097]

[0098]

[0099] By processing the test data in Table 1, we can obtain:

[0100] With p / b = 2, the average thickness value obtained from the four tests is (1.21 + 1.32 + 2.11 + 1.55) / 4 = 1.55;

[0101] With p / b = 4, the average thickness value obtained from the four tests is (0.53 + 0.82 + 0.66 + 0.71) / 4 = 0.68;

[0102] With p / b = 6, the average thickness value obtained from the four tests is (0.32 + 0.41 + 0.49 + 0.39) / 4 = 0.40;

[0103] With p / b = 8, the average thickness value obtained from the four tests is (0.26 + 0.31 + 0.29 + 0.26) / 4 = 0.28;

[0104] With p / b = 10, the average thickness value obtained from the four tests is (0.19 + 0.17 + 0.18 + 0.19) / 4 = 0.18;

[0105] With p / b = 12, the average thickness value obtained from the four tests is (0.05 + 0.09 + 0.12 + 0.10) / 4 = 0.09;

[0106] With p / b = 14, the average thickness value obtained from the four tests is (0.07 + 0.05 + 0.02 + 0.03) / 4 = 0.04.

[0107] In the case where higher requirements are imposed on the second wall 222, the thickness increase of the second wall 222 caused by material extrusion should be less than 0.2 mm. If it exceeds 0.2 mm, it is considered that a relatively serious impact is caused to the second wall 222. From the above test results, it can be seen that when p / b ≥ 10, the thickness increase value of the second wall 222 can reach a level less than or equal to 0.2, which can meet the requirements for the second wall 222 in most scenarios. In particular, when p / b ≥ 12, the thickness increase value of the second wall 222 can reach a level less than or equal to 0.1, and it can be considered that the material extrusion basically does not affect the second wall 222, which is applicable to scenarios with higher requirements for the second wall 222.

[0108] In order to accommodate as much material overflowing from the pressure relief notch 24 in various directions as possible, optionally, a plurality of isolation grooves 25 can also be arranged around the pressure relief notch 24. For example, isolation grooves 25 can be arranged on all four sides of the pressure relief notch 24.

[0109] The shape of the pressure relief notch 24 in the embodiments of the present application can be rectangular, annular, "I"-shaped, "cross"-shaped, unclosed "square"-shaped, and other possible shapes. Correspondingly, the isolation groove 25 can be set to have the same shape as the pressure relief notch 24, or can be set to have a different shape from the pressure relief notch 24.

[0110] In some embodiments, the projections of the pressure relief notch 24 and the isolation groove 25 on the first wall 221 can be rectangular to reduce the process complexity of the pressure relief notch 24 and the isolation groove 25. For example, as Figure 4 and Figure 5 shown, the pressure relief notch 24 is a rectangular notch, and the isolation groove 25 is also a rectangular notch. Among them, the long sides of the isolation groove 25 and the pressure relief notch 24 are parallel to the long side of the first wall 221, that is, parallel to the first direction X; the short sides of the isolation groove 25 and the pressure relief notch 24 are parallel to the short side of the first wall 221, that is, parallel to the second direction Y.

[0111] In some other embodiments, as Figures 6 to 8 shown, the projection of the pressure relief notch 24 on the first wall 221 includes a main body portion 241 extending along the first direction X, and two extension portions 242 respectively located at both ends of the main body portion 241 and extending along the second direction Y.

[0112] Among them, the first direction X intersects with the second direction Y. For example, the first direction X is parallel to the second wall 222, and the second direction Y is perpendicular to the second wall 222.

[0113] Hereinafter, taking the first direction X being parallel to the second wall 222 and the second direction Y being perpendicular to the second wall 222 as an example, the battery cell 20 of the embodiments of the present application will be described.

[0114] In this embodiment, the pressure relief notch 24 includes a main body portion 241 extending along the first direction X and two extension portions 242 respectively located at two ends of the main body portion 241 and extending along the second direction Y, so that the pressure inside the battery cell 20 can be released to the outside simultaneously along the first direction X and the second direction Y, improving the detonation uniformity of the pressure relief notch 24 and further improving the stability of the pressure relief notch 24.

[0115] In some embodiments, the extension portions 242 are located on both sides of the main body portion 241 in the second direction Y; or, the extension portions 242 are located on one side of the main body portion 241 in the second direction Y.

[0116] Among them, when the extension portions 242 are located on both sides of the main body portion 241 in the second direction Y, the pressure relief notch 24 is in a "worker" shape. For example, as Figure 6 or Figure 7 shown; when the extension portions 242 are located on one side of the main body portion 241 in the second direction Y, the pressure relief notch 24 is in an unclosed "square" shape. For example, as Figure 8 shown.

[0117] In some embodiments, the isolation groove 25 on the side where the extension portion 242 is located, the projection on the first wall 221 is located between the two extension portions 242 in the first direction X and does not extend beyond the ends of the two extension portions 242 in the second direction Y.

[0118] Since the position between the two extension portions 242 of the pressure relief notch 24 is where materials are likely to accumulate during the manufacturing process of the pressure relief notch 24, setting the isolation groove 25 between the two extension portions 242 enables the isolation groove 25 to accommodate more extruded materials, which is beneficial to reducing the impact of the materials on the surface of the housing 22 in subsequent processes.

[0119] For example, as Figure 6 and Figure 7 shown, Figure 6 and Figure 7 Taking 2 isolation grooves 25 and 4 isolation grooves 25 as examples respectively, the isolation grooves 25 are symmetrically distributed on both sides of the main body portion 241 of the pressure relief notch 24. The projection of the isolation groove 25 on the first wall 221 is located between the two extension portions 242 in the first direction X and does not extend beyond the ends of the two extension portions 242 in the second direction Y.

[0120] Again, for example, as Figure 8As shown, taking two isolation grooves 25 as an example, the two isolation grooves 25 are respectively arranged on both sides of the main body 241 of the pressure relief groove 24. Among them, the projection of the isolation groove 25 located on the upper side of the main body 241 of the pressure relief groove 24 on the first wall 221 is located between the two extensions 242 in the first direction X, and does not extend beyond the ends of the two extensions 242 in the second direction Y; the isolation groove 25 located on the lower side of the main body 241 has the same size as the isolation groove 25 located on the upper side of the main body 241, and is symmetrically arranged with respect to the main body 241.

[0121] Optionally, the dimension of the main body 241 along the first direction X is equal to the sum of the dimensions of the two extensions 242 along the second direction Y. This makes the lengths of the pressure release paths in the first direction X and the second direction Y the same, and the pressure relief groove 24 bears more uniform pressure, thereby improving the stability of the pressure relief groove 24.

[0122] Furthermore, when the widths of the main body 241 and the extension 242 are equal, that is, the dimension of the main body 241 in the second direction Y is equal to the dimension of the extension 242 in the first direction X, the area of ​​the main body 241 is equal to the sum of the areas of the two extensions 242, so that the areas of the pressure release paths in the first direction X and the second direction Y are the same, the pressure on the pressure relief mark 24 is more uniform, and the stability of the pressure relief mark 24 is improved.

[0123] In other embodiments, the projection of the pressure relief groove 24 onto the first wall 221 can be annular. Alternatively, the projection of the isolation groove 25 onto the first wall 221 can be annular, surrounding the pressure relief groove 24.

[0124] For example, such as Figure 9 As shown, both the pressure relief groove 24 and the isolation groove 25 are annular, with the isolation groove 25 surrounding the pressure relief groove 24. Since the material extruded during the creation of the annular pressure relief groove 24 overflows in all directions, setting the isolation groove 25 to be annular surrounding the pressure relief groove 24 can effectively block the material overflowing from all directions.

[0125] Of course, in addition to setting an annular isolation groove 25 in the outer area of ​​the pressure relief groove 24, an annular isolation groove 25 can also be set in the inner area of ​​the pressure relief groove 24.

[0126] It is understood that the aforementioned "ring" can be a circular or elliptical ring, and the ring can be closed along its circumference or have a gap along its circumference. Figure 9 Taking only a circular and closed annular shape as an example, this application does not limit the scope of the application.

[0127] In some embodiments, the volume of the main body 241 of the pressure relief groove 24 is less than or equal to the total volume of the isolation groove 25 located between the main body 241 and the second wall 222 on the first wall 221, so as to maximize the function of the isolation groove 25, so as to accommodate as much material as possible during the production of the pressure relief groove 24 and prevent the material from flowing to the surface of the housing 22 of the battery cell 20.

[0128] In order to reduce the impact of the isolation groove 25 on the pressure relief function of the pressure relief mark 24, in some embodiments, the thickness of the area where the isolation groove 25 is located on the first wall 221 is greater than or equal to the thickness of the area where the pressure relief mark 24 is located on the first wall 221. That is, the residual thickness of the isolation groove 25 on the first wall 221 is greater than or equal to the residual thickness of the pressure relief mark 24, or in other words, the depth of the isolation groove 25 is less than the depth of the pressure relief mark 24.

[0129] In the event of thermal runaway in the battery cell 20, the pressure relief groove 24 needs to open as quickly as possible to rapidly discharge the high-temperature, high-pressure waste generated inside the battery cell 20. Therefore, the thickness of the area containing the pressure relief groove 24 on the first wall 221 should be minimal to allow it to open preferentially.

[0130] In some embodiments, the thickness of the region where the isolation groove is located on the first wall 221 is greater than or equal to the thickness of the region where the pressure relief groove 24 is located on the first wall 221, and less than or equal to five times the thickness of the region where the pressure relief groove 24 is located on the first wall 221; preferably, the thickness of the region where the isolation groove 25 is located on the first wall 221 is greater than or equal to twice the thickness of the region where the pressure relief groove 24 is located on the first wall 221, and less than or equal to three times the thickness of the region where the pressure relief groove 24 is located on the first wall 221.

[0131] by Figure 4 and Figure 5 The rectangular pressure relief groove 24 and isolation groove 25 shown are used as examples for illustration. The depth relationship between pressure relief grooves 24 and isolation grooves 25 of other shapes is similar. d ≤ f ​​≤ 5d can be set, preferably 2d ≤ f ​​≤ 3d, where f is the thickness of the area containing the isolation groove 25 on the first wall 221, and d is the thickness of the area containing the pressure relief groove 24 on the first wall 221.

[0132] When the thickness f of the region where the isolation groove 25 is located on the first wall 221 satisfies the above relationship with the thickness d of the region where the pressure relief mark 24 is located, the influence of the isolation groove 25 on the pressure relief function of the pressure relief mark 24 can be reduced, and the isolation ability of the isolation groove 25 on the extruded material will not be affected.

[0133] As an example, as shown in Table 2, with Figure 6 or Figure 7Taking the "I"-shaped pressure relief notch 24 as an example, assuming the residual thickness d = 0.42 mm at the location of the pressure relief notch 24, the flatness of the second wall 222 of the shell 22 and the burst pressure (i.e., valve opening pressure) of the pressure relief notch 24 are tested under the conditions of f = d, f = 2d, f = 3d, f = 4d, and f = 5d, respectively. To improve the accuracy of the test results, 5 tests are performed, and the average value of the 5 tests can be used as the test result.

[0134] Table 2

[0135]

[0136]

[0137] Setting f to be greater than or equal to d, preferably greater than or equal to 2d, can reduce the impact of the isolation groove 25 on the burst pressure of the pressure relief groove 24; setting f to be less than or equal to 5d, preferably less than or equal to 3d, can increase the volume of the isolation groove 25, which is beneficial for the isolation groove 25 to block materials.

[0138] By processing the test data in Table 2, we can obtain:

[0139] When f = d, the average flatness obtained from 5 tests is (0.21 + 0.22 + 0.33 + 0.35 + 0.29) / 5 = 0.28, and the average burst pressure obtained from 5 tests is (0.42 + 0.44 + 0.43 + 0.46 + 0.44) / 5 = 0.44 MPa;

[0140] When f = 2d, the average flatness obtained from the 5 tests is (0.13 + 0.12 + 0.16 + 0.17 + 0.16) / 5 = 0.15, and the average burst pressure obtained from the 5 tests is (0.82 + 0.87 + 0.85 + 0.86 + 0.9) / 5 = 0.86 MPa;

[0141] When f = 3d, the average flatness obtained from 5 tests is (0.13 + 0.12 + 0.16 + 0.17 + 0.16) / 5 = 0.15, and the average burst pressure obtained from 5 tests is (0.82 + 0.87 + 0.85 + 0.86 + 0.9) / 5 = 0.86 MPa;

[0142] With f = 4d, the average flatness obtained from 5 tests is (0.23 + 0.32 + 0.25 + 0.23 + 0.28) / 5 = 0.26, and the average burst pressure obtained from 5 tests is (0.93 + 1.13 + 1.06 + 0.95 + 0.93) / 5 = 1.0 MPa;

[0143] With f = 5d, the average flatness obtained from the 5 tests is (0.34 + 0.32 + 0.35 + 0.38 + 0.29) / 5 = 0.34, and the average burst pressure obtained from the 5 tests is (1.12 + 0.95 + 0.89 + 0.85 + 1.07) / 5 = 0.98 MPa.

[0144] When the flatness requirement of the housing 22 is high, the flatness usually needs to be less than or equal to 0.2. When the requirement of the burst pressure of the pressure relief mark 24 is high, the burst pressure of the pressure relief mark 24 usually needs to be within the range of 1.0±0.2MPa.

[0145] As can be seen from Table 2, when 2d≤f≤3d, for example, 0.42 mm≤f≤2.1 mm, the flatness of the second wall 222 can reach a level of less than or equal to 0.2, which can meet the flatness requirements of the shell 22 in most scenarios. The burst pressure of the pressure relief mark 24 can be controlled within the range of 1.0±0.2 MPa, which can also meet the burst pressure requirements of the pressure relief mark 24 in most scenarios.

[0146] It is understandable that when the requirements for flatness and burst pressure are not high, the range of g can be appropriately expanded. For example, the range of f can be expanded to d≤f≤4d, such as 0.84 mm≤f≤1.68 mm; or, further expanded to d≤f≤5d, such as 0.84 mm≤f≤1.26 mm.

[0147] During the process of making the isolation groove 25 on the first wall 221, a certain amount of material will be extruded. In order to reduce the impact of this material on the surface of the shell 22 in subsequent processes, the distance between the isolation groove 25 and the second wall 222 in the direction perpendicular to the second wall 222 should not be too small.

[0148] In some embodiments, in the direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief mark 24 and the second wall 222 is greater than or equal to the dimension of the isolation groove 25 in the second direction Y; preferably, in the direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief mark 24 and the second wall 222 is greater than or equal to three times the dimension of the isolation groove 25 in the second direction Y.

[0149] Still with Figure 4 and Figure 5 Taking the rectangular pressure relief notch 24 and isolation groove 25 as an example, assuming the distance between the isolation groove 25 and the second wall 222 in the second direction Y is g, and the size of the isolation groove 25 is a. Then, g ≥ a can be set; preferably, g ≥ 3a can be set.

[0150] When the distance g between the isolation groove 25 and the second part 222 satisfies the above relationship, the impact of the material extruded during the manufacturing process of the isolation groove 25 on the second wall 222 in subsequent processes can be reduced.

[0151] As an example, as shown in Table 3, with Figure 6 or Figure 7 Taking the "I"-shaped pressure relief notch 24 as an example, assuming the dimension a = 2 mm of the isolation groove 25 in the second direction Y, the flatness of the second wall 222 of the housing 22 is tested under the conditions of g = 2, g = 4, g = 6, g = 8, g = 10, g = 12, and g = 14. To improve the accuracy of the test results, the average value of 5 tests is used as the test result.

[0152] Table 3

[0153]

[0154]

[0155] Setting g to be greater than or equal to a, preferably greater than or equal to 3a, can reduce the impact of materials generated during the manufacturing process of the isolation tank 25 on the second wall 222.

[0156] By processing the test data in Table 3, we can obtain:

[0157] With g=2, the average flatness obtained from 5 tests is (0.45+0.44+0.52+0.58+0.41) / 5=0.5;

[0158] With g=4, the average flatness obtained from 5 tests is (0.33+0.38+0.43+0.45+0.43) / 5=0.40;

[0159] With g=6, the average flatness obtained from 5 tests is (0.18+0.17+0.16+0.20+0.19) / 5=0.18;

[0160] With g=8, the average flatness obtained from 5 tests is (0.08+0.16+0.08+0.12+0.18) / 5=0.12;

[0161] With g=10, the average flatness obtained from 5 tests is (0.12+0.16+0.12+0.13+0.07) / 5=0.12;

[0162] With g=12, the average flatness obtained from 5 tests is (0.13+0.11+0.08+0.09+0.15) / 5=0.11;

[0163] With g=14, the average flatness obtained from 5 tests is (0.08+0.10+0.12+0.07+0.09) / 5=0.09.

[0164] When the flatness requirement of the housing 22 is high, the flatness usually needs to be less than or equal to 0.2.

[0165] As can be seen from Table 3, when g≥3a, for example, g≥6 mm, the flatness can reach a level of less than or equal to 0.2, which can meet the flatness requirements of the shell 22 in most scenarios.

[0166] It is understandable that when the flatness requirement is not high, the range of g can be appropriately expanded, for example, by expanding the range of g to g≥2a, such as g≥4 mm; or, further expanding it to g≥a, such as g≥2 mm.

[0167] Since the isolation groove 25 is integrally formed on the first wall 221, for example, by stamping the isolation groove 25 on the first wall 221, the isolation groove 25 must not only isolate the material extruded from the pressure relief mark 24, but also prevent the material extruded during the stamping process from affecting the shape of the pressure relief mark 24 and reducing its impact on the burst pressure of the pressure relief mark 24. Therefore, a suitable distance must be maintained between the isolation groove 25 and the pressure relief mark 24.

[0168] In some embodiments, in the direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief mark 24 and the pressure relief mark 24 is greater than or equal to the size of the isolation groove 25; optionally, in the direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief mark 24 and the pressure relief mark 24 is greater than or equal to three times the size of the isolation groove 25.

[0169] Still with Figure 4 and Figure 5 Taking the rectangular pressure relief notch 24 and isolation groove 25 as an example, assuming that the distance between the isolation groove 25 and the pressure relief notch 24 in the second direction Y is h, and the size of the isolation groove 25 is a. Then, h ≥ a can be set, and preferably, h ≥ 3a can be set.

[0170] For the isolation groove 25 set between the pressure relief groove 24 and the second wall 222, in the direction perpendicular to the second wall 222, the isolation groove 25 and the pressure relief groove 24 maintain a suitable distance. The distance maintained between the isolation groove 25 and the second wall 222 can reduce the impact of the material extruded during the fabrication of the isolation groove 25 on the second wall 222 in subsequent processes, and can also reduce the impact of the material extruded during the fabrication of the isolation groove 25 on the groove morphology of the pressure relief groove 24, thereby reducing the impact on the burst pressure of the pressure relief groove 24.

[0171] As an example, as shown in Table 4, with Figure 6 or Figure 7 Taking the "I"-shaped pressure relief notch 24 as an example, assuming the dimension a = 2 mm in the second direction Y, the burst pressure of the pressure relief notch 24 was tested under the conditions of h = 1, h = 2, h = 3, h = 4, h = 5, h = 6, and h = 7. To improve the accuracy of the test results, the average value of 5 tests was used as the test result.

[0172] Table 4

[0173]

[0174]

[0175]

[0176] Setting h to be greater than or equal to a, preferably greater than or equal to 3a, can reduce the influence of the material extruded during the fabrication of the isolation groove 25 on the groove morphology of the pressure relief groove 24, thereby reducing the impact on the burst pressure of the pressure relief groove 24.

[0177] By processing the test data in Table 4, we can obtain:

[0178] With h=1, the average burst pressure obtained from the 5 tests is (0.52+0.32+0.44+0.35+0.72) / 5=0.47MPa;

[0179] With h=2, the average burst pressure obtained from the 5 tests is (0.65+0.46+0.66+0.63+0.77) / 5=0.63MPa;

[0180] With h=3, the average burst pressure obtained from the 5 tests is (0.81+0.82+0.78+0.72+0.70) / 5=0.77MPa;

[0181] With h=4, the average burst pressure obtained from the 5 tests is (0.83+0.82+0.87+0.90+0.82) / 5=0.85MPa;

[0182] With h=5, the average burst pressure obtained from the 5 tests is (0.91+0.97+0.93+1.23+1.12) / 5=1.03MPa;

[0183] With h=6, the average burst pressure obtained from the 5 tests is (1.03+1.01+0.95+0.98+0.99) / 5=0.99MPa;

[0184] With h=7, the average burst pressure obtained from the 5 tests is (1.02+1.03+0.99+0.98+0.96) / 5=0.10MPa;

[0185] With h=8, the average burst pressure obtained from the 5 tests is (1.03+1.01+0.97+0.99+0.97) / 5=0.99MPa.

[0186] When the burst pressure requirement of the pressure relief notch 24 is high, the burst pressure of the pressure relief notch 24 usually needs to be within the range of 1.0±0.2MPa.

[0187] As can be seen from Table 4, when h≥3a, for example, h≥6 mm, the burst pressure of the pressure relief notch 24 can be controlled within the range of 1.0±0.2MPa, which can meet the requirements of the burst pressure of the pressure relief notch 24 in most scenarios.

[0188] It is understandable that when the requirements for flatness and burst pressure are not high, the range of h can be appropriately expanded, for example, by expanding the range of h to h≥2a, such as h≥4 mm; or, further expanding it to h≥a, such as h≥2 mm.

[0189] In some embodiments, the pressure relief notch 24 includes a single-step or multi-step structure. Each step in the step structure can be, for example, rectangular, trapezoidal, triangular, or other regular or irregular shapes. For the multi-step pressure relief notch 24, the multi-step structure can be generated during the process of forming the pressure relief notch 24 through multiple stamping processes. Specifically, during the process of making the pressure relief notch 24, the corresponding position of the first wall 221 can be stamped multiple times, and each stamping will form a single step, thereby obtaining the final pressure relief notch 24 through multiple forming processes. The staged forming of the pressure relief notch 24 can reduce the particle size of the extruded material and reduce the impact on the surface of the shell 22.

[0190] For example, such as Figure 10 As shown, the pressure relief groove 24 includes multiple steps 243, and the depth of each step 243 can be the same or different. Optionally, the depth of the multiple steps 243 can gradually increase from the inside to the outside of the battery cell 20, that is, the depth of each stamping increases with the number of stampings. Figure 10 As an example, the step structure shown includes a first step 243, a second step 243 and a third step 243 from top to bottom. The depth of the first step 243 is greater than the depth of the second step 243, and the depth of the second step 243 is greater than the depth of the third step 243. The first step 243 and the second step 243 are rectangular in shape, and the third step 243 is an inverted triangle in shape.

[0191] This application also provides a battery 100, including the battery cell 20 described in any of the above embodiments.

[0192] This application provides an electrical device, including the battery 100 described in any of the above embodiments. The battery 100 is used to provide electrical energy to the electrical device, which is, for example, a... Figure 1 Vehicle 1 is shown.

[0193] As can be seen from the above description, a pressure relief groove 24 is formed on the first wall 221 of the battery cell 20 in this embodiment of the application. At least one isolation groove 25 is also provided in the area between the pressure relief groove 24 and the second wall 222 on the first wall 221 to block the material extruded during the process of forming the pressure relief groove 24 on the first wall 221 from flowing to the second wall 222, thereby reducing the surface defects caused by the material extruded in subsequent processes to the second wall 222.

[0194] It should be noted that, without conflict, the various embodiments and / or technical features described in this application can be arbitrarily combined with each other, and the resulting technical solutions should also fall within the protection scope of this application.

[0195] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, The battery cell includes a first wall and a second wall perpendicular to the first wall. A pressure relief groove is integrally formed on the first wall. An isolation groove is provided on the first wall in the area between the pressure relief groove and the second wall. The pressure relief groove includes a main body portion, which is opposite to the isolation groove in a direction perpendicular to the second wall. Wherein, in the direction perpendicular to the second wall, the ratio between the distance between the main body and the second wall and the size of the main body is greater than or equal to 10.

2. The battery cell according to claim 1, characterized in that, In the direction perpendicular to the second wall, the ratio between the distance between the main body and the second wall and the size of the main body is greater than or equal to 12.

3. The battery cell according to claim 1, characterized in that, The number of isolation grooves is multiple, and the multiple isolation grooves are arranged on both sides of the pressure relief groove along a direction perpendicular to the second wall.

4. The battery cell according to claim 1, characterized in that, The opening of the isolation groove faces the same direction as the opening of the pressure relief groove.

5. The battery cell according to claim 1, characterized in that, The second wall is the wall with the largest area on the battery cell.

6. The battery cell according to claim 1, characterized in that, The projection of the pressure relief groove on the first wall includes the main body extending along a first direction and two extensions located at the two ends of the main body and extending along a second direction, wherein the first direction intersects the second direction.

7. The battery cell according to claim 6, characterized in that, The first direction is parallel to the second wall, and the second direction is perpendicular to the second wall.

8. The battery cell according to claim 6, characterized in that, The extension is located on one side of the main body in the second direction, or the extension is located on both sides of the main body in the second direction.

9. The battery cell according to claim 8, characterized in that, The isolation groove on the side where the extension is located is projected onto the first wall between the two extensions in the first direction, and does not extend beyond the ends of the two extensions in the second direction.

10. The battery cell according to claim 6, characterized in that, The dimension of the main body along the first direction is equal to the sum of the dimensions of the two extensions along the second direction.

11. The battery cell according to claim 1, characterized in that, The projection of the pressure relief markings on the first wall is a ring shape.

12. The battery cell according to claim 11, characterized in that, The projection of the isolation groove onto the first wall is an annular ring surrounding the pressure relief groove.

13. The battery cell according to claim 1, characterized in that, The thickness of the area where the isolation groove is located on the first wall is greater than the thickness of the area where the pressure relief groove is located on the first wall.

14. The battery cell according to claim 13, characterized in that, The thickness of the area where the isolation groove is located on the first wall is greater than or equal to the thickness of the area where the pressure relief groove is located on the first wall, and less than or equal to five times the thickness of the area where the pressure relief groove is located on the first wall.

15. The battery cell according to claim 14, characterized in that, The thickness of the area where the isolation groove is located on the first wall is greater than or equal to twice the thickness of the area where the pressure relief groove is located on the first wall, and less than or equal to three times the thickness of the area where the pressure relief groove is located on the first wall.

16. The battery cell according to claim 1, characterized in that, In a direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite the pressure relief groove and the second wall is greater than or equal to the size of the isolation groove.

17. The battery cell according to claim 16, characterized in that, In a direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite the pressure relief groove and the second wall is greater than or equal to three times the size of the isolation groove.

18. The battery cell according to claim 1, characterized in that, In the direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the pressure relief mark is greater than or equal to the size of the isolation groove.

19. The battery cell according to claim 18, characterized in that, In the direction perpendicular to the second wall, the distance between the portion of the isolation groove opposite to the pressure relief mark and the pressure relief mark is greater than or equal to three times the size of the isolation groove.

20. The battery cell according to any one of claims 1 to 19, characterized in that, The pressure relief grooves include a multi-step structure.

21. The battery cell according to any one of claims 1 to 19, characterized in that, The battery cell includes: Electrode assembly; Housing for accommodating the electrode assembly; and, An end cap is used to cover the electrode assembly within the housing, wherein the first wall is a wall on the housing opposite to the end cap.

22. A battery, characterized in that, Includes the battery cell according to any one of claims 1 to 21.

23. An electrical appliance, characterized in that, Includes the battery according to claim 22, the battery being used to provide electrical energy to the electrical device.

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