Battery cell, battery, and electrical apparatus

Abstract

A battery cell, a battery, and an electrical apparatus, capable of reducing the effect on the surface of the casing of the battery cell during the process of forming a pressure relief notch. The battery cell comprises a first wall and a second wall perpendicular to the first wall; a pressure relief notch is integrally formed on the first wall; an isolation groove is disposed in an area on the first wall between the pressure relief notch and the second wall; the pressure relief notch comprises a main body portion; the main body portion is opposite to the isolation groove in the direction perpendicular to the second wall, wherein in the direction perpendicular to the second wall, the ratio of the distance between the main body portion and the second wall to the size of the main body portion is greater than or equal to 10.

Description

Battery cells, batteries and electrical devices

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application No. 202311249667.0, filed on September 26, 2023, entitled “Battery Cell, Battery and Electrical Device,” the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become a crucial component of this sector's sustainable development. Battery technology is a crucial factor in the development of electric vehicles. Batteries are composed of single cells, each equipped with pressure relief notches to release internal pressure. Minimizing the impact of these pressure relief notches on other parts of the cell has become a pressing issue.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can reduce the impact on the shell surface of the battery cell during the formation of the pressure relief notch.

[0007] In a first aspect, a battery cell is provided, comprising a first wall and a second wall perpendicular to the first wall, wherein a pressure relief notch is integrally formed on the first wall, and an isolation groove is provided in an area of ​​the first wall between the pressure relief notch and the second wall, wherein the pressure relief notch comprises a main body portion, and the main body portion is opposite to the isolation groove in a direction perpendicular to the second wall.

[0008] In which, in the direction perpendicular to the second wall, the ratio of the distance between the main body and the second wall to the size of the main body is greater than or equal to 10; preferably, in the direction perpendicular to the second wall, the ratio of the distance between the main body and the second wall to the size of the main body is greater than or equal to 12.

[0009] During the process of stamping a pressure relief indentation on the first wall of the battery cell, the extruded material will flow to the periphery of the pressure relief indentation. During the process of forming the housing through processes such as precision drawing, this material may accumulate on the second wall perpendicular to the first wall, resulting in defects on the surface of the housing and affecting its flatness. In the present application, an isolation groove is provided on the first wall of the battery cell where the pressure relief indentation is provided. The isolation groove is located between the pressure relief indentation and the second wall, so that the isolation groove can accommodate the extruded material during the process of making the pressure relief indentation on the first wall, and block the material from flowing towards the second wall in subsequent processes, reducing the impact on the surface of the housing of the battery cell during the formation of the pressure relief indentation.

[0010] In some possible implementation manners, the opening of the isolation groove faces the same direction as the opening of the pressure relief indentation. In this way, the extruded material during the process of making the pressure relief indentation on the first wall can be blocked by the isolation groove in a timely manner.

[0011] 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 extruded material from both sides of the pressure relief indentation can be blocked by the isolation grooves on both sides.

[0012] In some possible implementation manners, the second wall is the wall with the largest area of the battery cell, also referred to as the "large wall". Since the impact on the large wall of the battery cell is the greatest during the manufacturing process of the pressure relief indentation, 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.

[0013] 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.

[0014] Among them, 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.

[0015] In this implementation manner, the pressure relief indentation can be in a shape similar to a "worker" 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 along the first direction and the second direction simultaneously, improving the detonation uniformity of the pressure relief indentation, and further improving the stability of the pressure relief indentation.

[0016] In some possible implementations, the projection of the isolation groove on the side of the extension portion on the first wall is located between the two extension portions in the first direction and does not extend beyond the ends of the two extension portions in the second direction. Since the area between the two extension portions of the pressure relief notch is prone to material accumulation during the production process, placing the isolation groove between the two extension portions allows the groove to accommodate more extruded material, which helps reduce the impact of this material on the surface of the battery cell casing during subsequent processing.

[0017] In some possible implementations, the size of the main body along the first direction is equal to the sum of the sizes of the two extensions along the second direction. This ensures that the lengths of the pressure relief paths in the first and second directions are the same, making the pressure on the pressure relief notch more uniform and improving the stability of the pressure relief notch.

[0018] In some possible implementations, the projection of the pressure relief notch on the first wall is annular. Using an annular pressure relief notch can release pressure inside the battery cell in all directions, improve the detonation uniformity of the pressure relief notch, and further improve the stability of the pressure relief notch.

[0019] In some possible implementations, the projection of the isolation groove on the first wall is an annular shape surrounding the pressure relief notch. Since extruded material overflows in all directions during the process of forming the annular pressure relief notch, configuring the isolation groove as an annular shape surrounding the pressure relief notch can effectively prevent material from overflowing in all directions.

[0020] In some possible implementations, the thickness of the region of the first wall where the isolation groove is located is greater than the thickness of the region of the first wall where the pressure relief notch is located. To ensure that the pressure relief function of the pressure relief notch is not affected, the depth of the isolation groove should be less than the depth of the pressure relief notch. In other words, the thickness of the region of the first wall where the isolation groove is located is greater than the thickness of the region where the pressure relief notch is located.

[0021] In some possible implementations, the thickness of the region on the first wall where the isolation groove is located is greater than or equal to the thickness of the region on the first wall where the pressure relief notch is located, and less than or equal to five times the thickness of the region on the first wall where the pressure relief notch is located. Preferably, the thickness of the region on the first wall where the isolation groove is located is greater than or equal to two times the thickness of the region on the first wall where the pressure relief notch is located, and less than or equal to three times the thickness of the region on the first wall where the pressure relief notch is located. When the thickness of the region on the first wall where the isolation groove is located and the thickness of the region where the pressure relief notch are located satisfy the above relationship, the effect of the isolation groove on the pressure relief function of the pressure relief notch can be reduced, while also not affecting the isolation groove's ability to isolate extruded material.

[0022] 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 notch 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 notch and the second wall is greater than or equal to three times the size of the isolation groove.

[0023] When the distance between the isolation groove and the second wall satisfies the above relationship, the material extruded during the production of the isolation groove on the first wall is not easy to flow to the second wall, thereby reducing the impact of the material extruded during the production of the isolation groove on the second wall in subsequent processes.

[0024] 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 notch and the pressure relief notch 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 notch and the pressure relief notch is greater than or equal to three times the size of the isolation groove.

[0025] When the distance between the isolation groove and the pressure relief notch satisfies the above relationship, the influence of the isolation groove on the notch morphology of the pressure relief notch during fabrication can be reduced, thereby reducing the influence on the bursting pressure of the pressure relief notch.

[0026] In some possible implementations, the pressure relief notch comprises a multi-step structure. During the production of the pressure relief notch, the corresponding position of the first wall may be stamped multiple times, with each stamping forming a step. The pressure relief notch is formed through multiple molding processes. The multi-step molding of the pressure relief notch can reduce the particle size of the extruded material and minimize the impact on the surface of the battery cell housing.

[0027] In some possible implementations, the battery cell includes an electrode assembly, a shell, and an end cap, wherein the shell is used to accommodate the electrode assembly, and the end cap is used to cover the electrode assembly within the shell, wherein the first wall is the wall of the shell opposite to the end cap, such as the bottom wall, that is, the pressure relief notch can be provided on the bottom wall of the shell. In this way, after the integrally scored pressure relief notch is stamped on the first wall, a shell with the pressure relief notch can be formed through a fine drawing process. Since the first wall is also provided with an isolation groove, the material extruded by stamping can be contained in the isolation groove and is not easily accumulated on the shell surface after the fine drawing process, thereby reducing the probability of defects such as protrusions on the shell surface.

[0028] In a second aspect, a battery is provided, comprising the battery cell described in the first aspect or any possible implementation of the first aspect.

[0029] In a third aspect, an electrical device is provided, comprising the battery described in the second aspect or any possible implementation of the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] FIG1 is a schematic structural diagram of a vehicle according to an embodiment of the present application.

[0032] FIG2 is a schematic structural diagram of a battery according to an embodiment of the present application.

[0033] FIG3 is a schematic structural diagram of a battery cell according to an embodiment of the present application.

[0034] FIG4 is a schematic side view of a pressure relief notch and an isolation groove according to an embodiment of the present application.

[0035] FIG5 is a schematic top view of the pressure relief notch and the isolation groove according to an embodiment of the present application.

[0036] FIG6 is a schematic diagram of a pressure relief notch and an isolation groove according to another embodiment of the present application.

[0037] FIG7 is a schematic diagram of a pressure relief notch and an isolation groove according to another embodiment of the present application.

[0038] FIG8 is a schematic diagram of a pressure relief notch and an isolation groove according to another embodiment of the present application.

[0039] FIG9 is a schematic diagram of a pressure relief notch and an isolation groove according to another embodiment of the present application.

[0040] FIG10 is a schematic diagram of the steps of the pressure relief notch according to an embodiment of the present application.

[0041] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0042] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0044] 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.

[0045] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0046] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0047] The term "multiple" as used in this application refers to two or more than two. Similarly, the term "multiple groups" refers to two or more than two groups, and the term "multiple sheets" refers to two or more than two sheets.

[0048] In the embodiments of the present application, the battery cells may be secondary batteries. A secondary battery refers to a battery cell that can be recharged to activate the active material after discharge and continue to be used. The battery cells may be, for example, 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., although the embodiments of the present application are not limited thereto.

[0049] A battery cell typically includes an electrode assembly. This assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of a battery cell, active ions, such as lithium ions, are inserted and removed between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits while allowing the active ions to pass through.

[0050] In some embodiments, the positive electrode may be a positive electrode sheet, which includes a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0051] The positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0052] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be silver-surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector may be formed by forming a metal material such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy on a polymer material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like.

[0053] Among them, the positive electrode active material includes, for example, at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. The present application is not limited to these materials, and other traditional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphates such as LiFePO4 (also referred to as LFP), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate such as LiMnPO4, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0054] 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.

[0055] The negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either one or both of the two facing surfaces of the negative electrode current collector.

[0056] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may include silver-surface-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium. The composite current collector may include a polymer base layer and a metal layer. The composite current collector may be formed by forming a metal material such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy on a polymer substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene.

[0057] The negative electrode active material includes, for example, at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.

[0058] In some embodiments, the negative electrode may also use a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. It should be noted that when the metal foam is used as the negative electrode, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0059] Optionally, the negative electrode current collector may be filled with or / and deposited with a lithium source material, potassium metal, or sodium metal, where the lithium source material includes lithium metal and / or lithium-rich material.

[0060] The material of the positive electrode current collector may be, for example, aluminum, and the material of the negative electrode current collector may be, for example, copper.

[0061] The separator in the electrode assembly is disposed between the positive electrode and the negative electrode. 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 used. For example, the primary material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic.

[0062] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0063] In some embodiments, the battery cell also 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, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0064] In an embodiment of the present application, the electrode assembly may be a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound to form a wound structure. The electrode assembly may also be a laminated structure, for example, the positive electrode sheet and the negative electrode sheet may be provided in a plurality, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are alternately stacked. Alternatively, the positive electrode sheet may be provided in a plurality, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet sandwiched between adjacent folded segments; or, both the positive electrode sheet and the negative electrode sheet may be folded to form a plurality of stacked folded segments.

[0065] There may be multiple separators, each of which is disposed between any adjacent positive electrode sheets and negative electrode sheets.

[0066] In some embodiments, the separator may be provided continuously and disposed between any adjacent positive electrode sheets and negative electrode sheets by folding or winding.

[0067] The shape of the electrode assembly can be, for example, cylindrical, flat, or polygonal. The electrode assembly can be provided with tabs, including a positive tab and a negative tab, for conducting current from the electrode assembly.

[0068] In some embodiments, a battery cell includes a housing. The housing is used to encapsulate components such as the electrode assembly and electrolyte. The housing can be steel, aluminum, plastic such as polypropylene, composite metal such as a copper-aluminum composite, or aluminum-plastic film. The housing includes a housing and a cover.

[0069] The battery cells may be, for example, cylindrical battery cells, prismatic battery cells, soft-pack battery cells or battery cells of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells or polygonal batteries, among which polygonal batteries may be hexagonal batteries, etc. This application does not impose any restrictions on this.

[0070] The battery described in the embodiments of the present application can be a single physical module including 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, in parallel or in hybrid through a busbar.

[0071] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0072] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are housed in the case.

[0073] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the vehicle floor, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0074] For batteries, the primary safety hazard arises from the charging and discharging processes. To improve battery safety, pressure relief mechanisms are typically installed on battery cells. A pressure relief mechanism, for example, is a component or element that activates to release the internal pressure or temperature of a battery cell when the internal pressure or temperature reaches a predetermined threshold. This threshold can be adjusted based on the battery design requirements. This threshold may depend on the materials of one or more of the positive and negative electrode plates, electrolyte, and separator within the battery cell. The pressure relief mechanism can be implemented as a pressure- or temperature-sensitive element or component. Specifically, when the internal pressure or temperature of the battery cell reaches this threshold, the pressure relief mechanism activates, creating a channel for the internal pressure or temperature to be released. Upon activation, the high-temperature, high-pressure substances within the battery cell are discharged from the pressure relief mechanism to the exterior of the battery cell. In this way, pressure relief can be achieved within the battery cell under controlled pressure or temperature conditions, thereby avoiding potentially more serious accidents. Among them, the emissions of the battery cell include but are not limited to high-temperature and high-pressure gas generated by the reaction, electrolyte, dissolved or split positive and negative electrode plates, fragments of the isolation membrane, flames, etc.

[0075] For notch-type pressure relief mechanisms, they are usually integrally formed on the surface of the battery cell shell. In the embodiments of this application, this type of pressure relief mechanism is also referred to as a pressure relief notch. For example, the pressure relief notch can be formed by stamping. During the stamping process, the material extruded will flow around the pressure relief notch. During the subsequent process of forming the shell through processes such as fine drawing, the material may accumulate on the surface of the battery cell shell, thereby causing defects on the shell surface and affecting its flatness.

[0076] In view of this, an embodiment of the present application aims to provide an isolation groove on the first wall of the battery cell for providing the pressure relief notch to prevent the material extruded during the production of the pressure relief notch from flowing toward the shell surface, thereby solving the impact of the material on the shell surface.

[0077] 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.

[0078] 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 described using electric vehicles as an example.

[0079] For example, as shown in FIG1 , it is a structural schematic diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A motor 300, a controller 200 and a battery 100 may be provided inside the vehicle 1. The controller 200 is used to control the battery 100 to supply power to the motor 300. For example, a battery 100 may be provided at the bottom, front or rear of the vehicle 1. The battery 100 may be used to power the vehicle 1. For example, the battery 100 may 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 during the start-up, navigation and operation of the vehicle 1. In another embodiment of the present application, the battery 100 may not only be used 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 power for the vehicle 1.

[0080] To meet different power requirements, a battery can include multiple different types of battery cells. Multiple battery cells can be connected in series, in parallel, or in a hybrid manner according to the type of battery cell to form multiple battery cell groups, and the multiple battery cell groups are then connected in series to form a battery, where hybrid is a mixture of series and parallel connections. Multiple different battery cells can also be directly connected in series, in parallel, or in a hybrid manner to form a battery. In other words, multiple battery cells can be directly combined into a battery, or they can be first combined into battery cell groups according to the type of battery cells, and then the battery cell groups are formed into a battery.

[0081] FIG2 shows a schematic structural diagram of a battery 100 according to an embodiment of the present application. The battery 100 may include a plurality of battery cells 20. The battery 100 may further include a housing 10, the interior of which is a hollow structure, and the plurality of battery cells are accommodated in 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 snapped 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 may have an opening.

[0082] For example, as shown in FIG2 , the first housing portion 11 and the second housing portion 12 can both be hollow structures with only one open surface. The openings of the first housing portion 11 and the second housing portion 12 are arranged opposite each other, and the first housing portion 11 and the second housing portion 12 are interlocked to form a housing 10 having a closed chamber. Multiple battery cells are connected in parallel, series, or in a mixed combination and placed in the housing 10 formed by the interlocking of the first housing portion 11 and the second housing portion 12.

[0083] For another example, unlike Figure 2 , only one of the first and second housing portions 11, 12 is a hollow rectangular parallelepiped with an opening, while the other is plate-shaped to cover the opening. For example, if the second housing portion 12 is a hollow structure with only one open surface, and the first housing portion 11 is plate-shaped, then the first housing portion 11 covers the opening of the second housing portion 12 to form a housing 10 with a closed chamber that can accommodate multiple battery cells. Multiple battery cells are connected in parallel, series, or in a mixed combination and then placed within the housing 10 formed by the first and second housing portions 11, 12 being fastened together.

[0084] In addition, the battery 100 may also include other structures, such as a signal transmission group 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 may include, for example, a temperature sensor and voltage sampling lines, for measuring and transmitting information such as the battery voltage, current, and temperature, and for communicating with the BMS to achieve safe management of the battery 100.

[0085] In some embodiments, the signal transmission assembly may further include a busbar component, which is used to achieve electrical connection between multiple battery cells, such as parallel, series, or mixed connection. The busbar component can achieve electrical connection between battery cells by connecting the electrode terminals of the battery cells. In some embodiments, the busbar component can be fixed to the electrode terminals of the battery cells by welding. The busbar component transmits the voltage of the battery cells. When multiple battery cells are connected in series, a higher voltage will be obtained. Accordingly, the electrical connection formed by the busbar component can also be called a "high voltage connection."

[0086] As an example, FIG3 shows a schematic structural diagram of a battery cell 20 according to an embodiment of the present application. As an example, as shown in FIG3 , the battery cell 20 includes an electrode assembly 21, a housing 22, and an end cap 23. The housing 22 is used to accommodate the electrode assembly 21, and the end cap 23 is used to cover the electrode assembly 21 within the housing 22. The end cap 23 and the housing 22 can be connected by welding or other means.

[0087] In the embodiment of the present 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 , a pressure relief notch 24 is provided on the first wall 221 , and an isolation groove 25 is provided in the area between the pressure relief notch 24 and the second wall 222 on the first wall 221 .

[0088] As an example, as shown in FIG3 , the first wall 221 may be the wall of the shell 22 opposite to the end cover 23, i.e., the bottom wall of the shell 22. Optionally, the pressure relief notch 24 is a notch formed on the first wall 221 through an integral molding process. For example, the integrally-indented pressure relief notch 24 may be formed by punching the first wall 221 using a punch press. During the punching process, the material punched out of the notch of the pressure relief notch 24 may flow to the periphery of the pressure relief notch 24. During the process of forming the shell 22 through a fine drawing process, the material may accumulate on the surface of the shell 22, such as on the second wall 222 perpendicular to the first wall 221, causing surface defects of the shell 22, such as protrusions, and affecting the flatness of the surface of the shell 22.

[0089] The second wall 222 can be, for example, the largest wall of the battery cell 20, also known as the "large wall." Because the pressure relief notch 24 has the greatest impact on the large wall of the battery cell 20 during manufacturing, disposing the isolation groove 25 between the pressure relief notch 24 and the large wall helps reduce the impact on the large wall of the battery cell 20.

[0090] In an embodiment of the present application, an isolation groove 25 is provided on the first wall 221 of the battery cell 20 for setting the pressure relief notch 24. The isolation groove 25 is located between the pressure relief notch 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 notch 24 on the first wall 221, and prevent the material from flowing toward the second wall 222 in subsequent processes, thereby reducing the impact on the surface of the shell 22 of the battery cell 20.

[0091] In some embodiments, the opening of the isolation groove 25 is oriented in the same direction as the opening of the pressure relief notch 24 . In this way, the material extruded during the process of forming the pressure relief notch 24 on the first wall 221 can be promptly blocked by the isolation groove 25 .

[0092] In some embodiments, there are multiple isolation grooves 25, and the isolation grooves 25 are arranged on both sides of the pressure relief score 24 in a direction perpendicular to the second wall 222. In this way, the material extruded from both sides of the pressure relief score 24 can be blocked by the isolation grooves 25 on both sides. For example, the isolation grooves 25 can be symmetrically arranged on both sides of the pressure relief score 24.

[0093] Optionally, the pressure relief notch 24 includes a main body portion 241, which is opposite to the isolation groove 25 in the direction 222 perpendicular to the second wall, wherein in the direction 222 perpendicular to the second wall, the ratio of the distance between the main body portion 241 and the second wall 222 to the size of the main body portion 241 is greater than or equal to 10; preferably, in the direction 222 perpendicular to the second wall, the ratio of the distance between the main body portion 241 and the second wall 222 to the size of the main body portion 241 is greater than or equal to 12.

[0094] It is understood that the portion of the pressure relief notch 24 where a large amount of extruded material is present, such as the main body 241, particularly requires isolation. If the distance between the main body 241 and the second wall 222 is too small in a direction perpendicular to the second wall 222, the extruded material corresponding to the main body 241 is more likely to flow to the second wall 222, thereby 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 during subsequent processing.

[0095] The distance between the main body 241 and the second wall 222 in a direction perpendicular to 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 enough space to flow evenly without affecting the surface of the second wall 222. Therefore, the isolation groove 25 can be omitted between the main body 241 and the second wall 222. 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 during subsequent processes, thereby affecting the second wall 222. The larger the size of the main body 241 in a direction perpendicular to the second wall 222, the more extruded material corresponding to the main body 241, and the larger the distance between the pressure relief notch 24 and the second wall 222 should be. Setting the ratio of the distance between the main body 241 and the second wall 222 to 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 notch 24 on the second wall 222 during the manufacturing process.

[0096] In the embodiment of the present application, the direction perpendicular to the second wall 222 may be a direction having an angle of 90° with the second wall 222, or, due to deviations caused by the manufacturing process, deformation during battery use, etc., the angle between the direction and the second wall 222 may not be strictly equal to 90°, but may be slightly less than or slightly greater than 90°.

[0097] As an example, as shown in Figures 4 and 5 , two isolation grooves 25 are located on either side of the pressure relief notch 24 along a second direction Y perpendicular to the second wall 222. In the second direction Y, the ratio of the distance p between the pressure relief notch 24 and the second wall 222 to the dimension b of the pressure relief notch 24 is p / b ≥ 10; preferably, p / b ≥ 12. It should be noted that for the rectangular pressure relief notch 24 shown in Figures 4 and 5 , the main body 241 is the entire pressure relief notch 24.

[0098] As shown in Table 1, assuming that the dimension b of the pressure relief notch 24 in the second direction Y is 4 mm, the thickness of the second wall 222 of the test housing 22 exceeds the standard wall thickness when p / b = 2, p / b = 4, p / b = 6, p / b = 8, p / b = 10, p / b = 12, and p / b = 14, respectively. This represents the increased thickness of the second wall 222. To improve the accuracy of the test results, four tests were performed, and the average of the four tests was used as the test result.

[0099] Table 1

[0100] By processing the test data in Table 1, we can get:

[0101] When p / b = 2, the mean of the thickening values ​​obtained from 4 tests is (1.21 + 1.32 + 2.11 + 1.55) / 4 = 1.55;

[0102] When p / b = 4, the mean of the thickening values ​​obtained from 4 tests is (0.53 + 0.82 + 0.66 + 0.71) / 4 = 0.68;

[0103] When p / b=6, the mean of the thickening values ​​obtained from 4 tests is (0.32+0.41+0.49+0.39) / 4=0.40;

[0104] When p / b = 8, the mean of the thickening values ​​obtained from 4 tests is (0.26 + 0.31 + 0.29 + 0.26) / 4 = 0.28;

[0105] When p / b = 10, the mean of the thickening values ​​obtained from 4 tests is (0.19 + 0.17 + 0.18 + 0.19) / 4 = 0.18;

[0106] When p / b = 12, the mean of the thickening values ​​obtained from 4 tests is (0.05 + 0.09 + 0.12 + 0.10) / 4 = 0.09;

[0107] When p / b=14, the average of the thickening values ​​obtained from four tests is (0.07+0.05+0.02+0.03) / 4=0.04.

[0108] In situations where the requirements for the second wall 222 are high, the increase in thickness of the second wall 222 caused by material extrusion should be less than 0.2 mm. A thickness exceeding 0.2 mm is considered to have a significant impact on the second wall 222. The test results above show that when p / b ≥ 10, the increase in thickness of the second wall 222 can be less than or equal to 0.2, meeting the requirements for the second wall 222 in most scenarios. In particular, when p / b ≥ 12, the increase in thickness of the second wall 222 can be less than or equal to 0.1, indicating that material extrusion will have little impact on the second wall 222, making this suitable for scenarios with higher requirements for the second wall 222.

[0109] In order to accommodate as much material as possible that overflows from the pressure relief notch 24 in all directions, optionally, a plurality of isolation grooves 25 can also be provided around the pressure relief notch 24. For example, isolation grooves 25 can be provided around the pressure relief notch 24.

[0110] The shape of the pressure relief notch 24 in the embodiment of the present application can be rectangular, annular, I-shaped, X-shaped, an unclosed O-shaped, and other possible shapes. Accordingly, the isolation groove 25 can be set to the same shape as the pressure relief notch 24, or can be set to a shape different from the pressure relief notch 24.

[0111] 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 shown in Figures 4 and 5, the pressure relief notch 24 is a rectangular notch, and the isolation groove 25 is also a rectangular notch. The long sides of the isolation groove 25 and the pressure relief notch 24 are parallel to the long sides 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 sides of the first wall 221, that is, parallel to the second direction Y.

[0112] In other embodiments, as shown in FIG6 to FIG8 , the projection of the pressure relief notch 24 on the first wall 221 includes a main body 241 extending along the first direction X, and two extensions 242 located at two ends of the main body 241 and extending along the second direction Y.

[0113] The first direction X intersects 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 .

[0114] Hereinafter, the battery cell 20 of the embodiment of the present application will be described by taking the example that the first direction X is parallel to the second wall 222 and the second direction Y is perpendicular to the second wall 222 .

[0115] In this embodiment, the pressure relief notch 24 includes a main body 241 extending along the first direction X, and two extension portions 242 located at two ends of the main body 241 and extending along the second direction Y, so that the pressure inside the battery cell 20 can be released to the outside thereof simultaneously along the first direction X and the second direction Y, thereby improving the detonation uniformity of the pressure relief notch 24 and thereby improving the stability of the pressure relief notch 24.

[0116] In some embodiments, the extension portion 242 is located on both sides of the main body portion 241 in the second direction Y; or, the extension portion 242 is located on one side of the main body portion 241 in the second direction Y.

[0117] Among them, when the extension portion 242 is located on both sides of the main body 241 in the second direction Y, the pressure relief notch 24 is in the shape of an "I", for example, as shown in Figure 6 or Figure 7; when the extension portion 242 is located on one side of the main body 241 in the second direction Y, the pressure relief notch 24 is in the shape of an unclosed "mouth", for example, as shown in Figure 8.

[0118] In some embodiments, the projection of the isolation groove 25 on the side where the extension portion 242 is located on the first wall 221 is located between the two extension portions 242 in the first direction X and does not exceed the ends of the two extension portions 242 in the second direction Y.

[0119] Since the area between the two extensions 242 of the pressure relief notch 24 is where materials are easily accumulated during the production process of the pressure relief notch 24, the isolation groove 25 is set between the two extensions 242 so that the isolation groove 25 can accommodate more extruded materials, which is beneficial to reducing the impact of the material on the surface of the shell 22 in subsequent processes.

[0120] For example, as shown in Figures 6 and 7, Figures 6 and 7 take two isolation grooves 25 and four isolation grooves 25 as examples respectively. The isolation grooves 25 are symmetrically distributed on both sides of the main body 241 of the pressure relief notch 24. The projection of the isolation grooves 25 on the first wall 221 is located between the two extension portions 242 in the first direction X, and does not exceed the ends of the two extension portions 242 in the second direction Y.

[0121] For another example, as shown in FIG8 , two isolation grooves 25 are provided on either side of the main portion 241 of the pressure relief notch 24. The projection of the isolation groove 25 located on the upper side of the main portion 241 of the pressure relief notch 24 onto 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 portion 241 has the same dimensions as the isolation groove 25 located on the upper side of the main portion 241 and is symmetrically disposed relative to the main portion 241.

[0122] Optionally, the size of the main body 241 along the first direction X is equal to the sum of the sizes 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 on the pressure relief notch 24 is more uniform, thereby improving the stability of the pressure relief notch 24.

[0123] Furthermore, when the widths of the main body 241 and the extension portion 242 are equal, that is, the size of the main body 241 in the second direction Y is equal to the size of the extension portion 242 in the first direction X, the area of ​​the main body 241 is equal to the sum of the areas of the two extension portions 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 notch 24 is more uniform, and the stability of the pressure relief notch 24 is improved.

[0124] In other embodiments, the projection of the pressure relief notch 24 on the first wall 221 may be annular. Alternatively, the projection of the isolation groove 25 on the first wall 221 may be annular and surround the pressure relief notch 24.

[0125] For example, as shown in FIG9 , the pressure relief notch 24 and the isolation groove 25 are both annular, and the isolation groove 25 is provided to surround the pressure relief notch 24. Since the extruded material overflows in all directions during the process of making the annular pressure relief notch 24, the isolation groove 25 is provided in an annular shape surrounding the pressure relief notch 24, which can effectively block the material from overflowing in all directions.

[0126] Of course, in addition to providing the annular isolation groove 25 in the outer area of ​​the pressure relief notch 24 , an annular isolation groove 25 may also be provided in the inner area of ​​the pressure relief notch 24 .

[0127] It is understood that the above-mentioned "ring" can be a circular or elliptical ring, and the ring can be closed along its circumference or have a gap along its circumference. FIG9 only takes a circular and closed ring as an example, and this application does not limit this.

[0128] In some embodiments, the volume of the main body 241 of the pressure relief notch 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 role of the isolation groove 25 and accommodate as much material as possible squeezed out during the process of making the pressure relief notch 24, thereby preventing the material from flowing to the surface of the shell 22 of the battery cell 20.

[0129] In order to reduce the impact of the isolation groove 25 on the pressure relief function of the pressure relief notch 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 notch 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 notch 24, or in other words, the depth of the isolation groove 25 is less than the depth of the pressure relief notch 24.

[0130] In the event of thermal runaway of the battery cell 20, the pressure relief notch 24 needs to be opened as quickly as possible to quickly discharge the high-temperature and high-pressure waste generated inside the battery cell 20. Therefore, the thickness of the area where the pressure relief notch 24 is located on the first wall 221 should be the smallest to enable it to be opened first.

[0131] In some embodiments, the thickness of the area where the isolation groove on the first wall 221 is located is greater than or equal to the thickness of the area where the pressure relief notch 24 on the first wall 221 is located, and is less than or equal to five times the thickness of the area where the pressure relief notch 24 on the first wall 221 is located; preferably, the thickness of the area where the isolation groove 25 on the first wall 221 is located is greater than or equal to twice the thickness of the area where the pressure relief notch 24 on the first wall 221 is located, and is less than or equal to three times the thickness of the area where the pressure relief notch 24 on the first wall 221 is located.

[0132] The rectangular pressure relief notch 24 and isolation groove 25 shown in Figures 4 and 5 are used as examples for illustration. The depth relationship between pressure relief notches 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 region on the first wall 221 where the isolation groove 25 is located, and d is the thickness of the region on the first wall 221 where the pressure relief notch 24 is located.

[0133] When the above relationship is satisfied between the thickness f of the area where the isolation groove 25 is located on the first wall 221 and the thickness d of the area where the pressure relief notch 24 is located, the influence of the isolation groove 25 on the pressure relief function of the pressure relief notch 24 can be reduced, and the isolation ability of the isolation groove 25 on the extruded material will not be affected.

[0134] As an example, as shown in Table 2, using the "I"-shaped pressure relief notch 24 shown in Figures 6 or 7 as an example, assuming a residual thickness d = 0.42 mm at the location of the pressure relief notch 24, the flatness of the second wall 222 of the housing 22 and the burst pressure, or valve opening pressure, of the pressure relief notch 24 were tested under the conditions f = d, f = 2d, f = 3d, f = 4d, and f = 5d. To improve the accuracy of the test results, five tests were performed, and the average of the five tests was used as the test result.

[0135] Table 2

[0136] f is set to be greater than or equal to d, preferably, greater than or equal to 2d, which can reduce the impact of the isolation groove 25 on the bursting pressure of the pressure relief notch 24; f is set to be less than or equal to 5d, preferably, less than or equal to 3d, which can increase the volume of the isolation groove 25, which is beneficial to the isolation groove 25 blocking the material.

[0137] By processing the test data in Table 2, we can get:

[0138] 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;

[0139] When f = 2d, 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;

[0140] 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;

[0141] When 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;

[0142] When f=5d, the average flatness obtained from 5 tests is (0.34+0.32+0.35+0.38+0.29) / 5=0.34, and the average bursting pressure obtained from 5 tests is (1.12+0.95+0.89+0.85+1.07) / 5=0.98 MPa.

[0143] When the flatness requirement of the shell 22 is high, the flatness usually needs to be less than or equal to 0.2. When the bursting pressure requirement of the pressure relief notch 24 is high, the bursting pressure of the pressure relief notch 24 usually needs to be within the range of 1.0±0.2 MPa.

[0144] 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 less than or equal to 0.2, which can meet the flatness requirements of the shell 22 in most scenarios. The bursting pressure of the pressure relief score 24 can be controlled within the range of 1.0 ± 0.2 MPa, which can also meet the bursting pressure requirements of the pressure relief score 24 in most scenarios.

[0145] It can be understood that when the requirements for flatness and bursting 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, for example, 0.84 mm≤f≤1.68 mm; or further expanded to d≤f≤5d, for example, 0.84 mm≤f≤1.26 mm.

[0146] During the process of making the isolation groove 25 on the first wall 221, a certain amount of material will also be squeezed out. In order to reduce the impact of this part of the material on the surface of the shell 22 in the subsequent process, 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.

[0147] In some embodiments, in a direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief notch 24 and the second wall 222 is greater than or equal to the size of the isolation groove 25 in the second direction Y; preferably, in a direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief notch 24 and the second wall 222 is greater than or equal to three times the size of the isolation groove 25 in the second direction Y.

[0148] Still taking the rectangular pressure relief notch 24 and isolation groove 25 shown in FIG4 and FIG5 as an example, assuming that 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.

[0149] When the distance g between the isolation groove 25 and the second portion 222 satisfies the above relationship, the influence of the material extruded during the manufacturing process of the isolation groove 25 on the second wall 222 in subsequent processes can be reduced.

[0150] As an example, as shown in Table 3, using the "I"-shaped pressure relief notch 24 shown in Figures 6 or 7 as an example, assuming that the dimension a of the isolation groove 25 in the second direction Y is 2 mm, the flatness of the second wall 222 of the housing 22 was 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 of five tests was used as the test result.

[0151] Table 3

[0152] g is set to be greater than or equal to a, preferably, to be greater than or equal to 3a, which can reduce the impact of materials generated during the manufacturing process of the isolation groove 25 itself on the second wall 222.

[0153] By processing the test data in Table 3, we can get:

[0154] When g = 2, the average flatness obtained from 5 tests is (0.45 + 0.44 + 0.52 + 0.58 + 0.41) / 5 = 0.5;

[0155] When g = 4, the average flatness obtained from 5 tests is (0.33 + 0.38 + 0.43 + 0.45 + 0.43) / 5 = 0.40;

[0156] When g = 6, the average flatness obtained from 5 tests is (0.18 + 0.17 + 0.16 + 0.20 + 0.19) / 5 = 0.18;

[0157] When g = 8, the average flatness obtained from 5 tests is (0.08 + 0.16 + 0.08 + 0.12 + 0.18) / 5 = 0.12;

[0158] When g = 10, the average flatness obtained from 5 tests is (0.12 + 0.16 + 0.12 + 0.13 + 0.07) / 5 = 0.12;

[0159] When g = 12, the average flatness obtained from 5 tests is (0.13 + 0.11 + 0.08 + 0.09 + 0.15) / 5 = 0.11;

[0160] When g=14, the average flatness obtained from 5 tests is (0.08+0.10+0.12+0.07+0.09) / 5=0.09.

[0161] When the flatness requirement for the housing 22 is high, the flatness generally needs to be less than or equal to 0.2.

[0162] As can be seen from Table 3, when g ≥ 3a, for example, g ≥ 6 mm, the flatness can reach a level less than or equal to 0.2, which can meet the flatness requirements of the shell 22 in most scenarios.

[0163] It can be understood that when the requirements for flatness are not high, the range of g can be appropriately expanded, for example, the range of g can be expanded to g≥2a, for example, g≥4 mm; or further expanded to g≥a, for example, g≥2 mm.

[0164] Since the isolation groove 25 is integrally formed on the first wall 221, for example, the isolation groove 25 is formed by stamping on the first wall 221, the isolation groove 25 must not only isolate the material extruded from the pressure relief notch 24, but also prevent the material extruded during the stamping process from affecting the morphology of the pressure relief notch 24, thereby reducing its impact on the bursting pressure of the pressure relief notch 24. Therefore, a suitable distance needs to be maintained between the isolation groove 25 and the pressure relief notch 24.

[0165] In some embodiments, in a direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief notch 24 and the pressure relief notch 24 is greater than or equal to the size of the isolation groove 25; optionally, in a direction perpendicular to the second wall 222, the distance between the portion of the isolation groove 25 opposite to the pressure relief notch 24 and the pressure relief notch 24 is greater than or equal to three times the size of the isolation groove 25.

[0166] Still taking the rectangular pressure relief notch 24 and isolation groove 25 shown in FIG4 and FIG5 as an example, assuming that the distance between isolation groove 25 and pressure relief notch 24 in the second direction Y is h, and the size of isolation groove 2 is a, then h ≥ a can be set, preferably h ≥ 3a.

[0167] For the isolation groove 25 arranged between the pressure relief score 24 and the second wall 222, an appropriate distance is maintained between the isolation groove 25 and the pressure relief score 24 in the direction perpendicular to the second wall 222, and the distance maintained between the isolation groove 25 and the second wall 222 can not only reduce the impact of the material extruded during the manufacturing process of the isolation groove 25 on the second wall 222 in the subsequent process, but also reduce the impact of the material extruded during the manufacturing process of the isolation groove 25 on the score morphology of the pressure relief score 24, thereby reducing the impact on the bursting pressure of the pressure relief score 24.

[0168] As an example, as shown in Table 4, using the "I"-shaped pressure relief notch 24 shown in Figures 6 or 7 as an example, assuming that the dimension a of the pressure relief notch 24 in the second direction Y is 2 mm, the burst pressure of the pressure relief notch 24 was tested under the conditions 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 of five tests was used as the test result.

[0169] Table 4

[0170] h is set to be greater than or equal to a, preferably, set to be greater than or equal to 3a, which can reduce the impact of the material extruded during the production of the isolation groove 25 on the notch morphology of the pressure relief notch 24, thereby reducing the impact on the bursting pressure of the pressure relief notch 24.

[0171] By processing the test data in Table 4, we can obtain:

[0172] When h = 1, the average burst pressure obtained from 5 tests is (0.52 + 0.32 + 0.44 + 0.35 + 0.72) / 5 = 0.47 MPa;

[0173] When h = 2, the average burst pressure obtained from 5 tests is (0.65 + 0.46 + 0.66 + 0.63 + 0.77) / 5 = 0.63 MPa;

[0174] When h = 3, the average burst pressure obtained from 5 tests is (0.81 + 0.82 + 0.78 + 0.72 + 0.70) / 5 = 0.77 MPa;

[0175] When h = 4, the average burst pressure obtained from 5 tests is (0.83 + 0.82 + 0.87 + 0.90 + 0.82) / 5 = 0.85 MPa;

[0176] When h = 5, the average burst pressure obtained from 5 tests is (0.91 + 0.97 + 0.93 + 1.23 + 1.12) / 5 = 1.03 MPa;

[0177] When h = 6, the average burst pressure obtained from 5 tests is (1.03 + 1.01 + 0.95 + 0.98 + 0.99) / 5 = 0.99 MPa;

[0178] When h = 7, the average burst pressure obtained from 5 tests is (1.02 + 1.03 + 0.99 + 0.98 + 0.96) / 5 = 0.10 MPa;

[0179] When h=8, the average burst pressure obtained from 5 tests is (1.03+1.01+0.97+0.99+0.97) / 5=0.99 MPa.

[0180] When the bursting pressure requirement of the pressure relief score 24 is high, the bursting pressure of the pressure relief score 24 generally needs to be within the range of 1.0±0.2 MPa.

[0181] It can be seen from Table 4 that when h≥3a, for example, h≥6 mm, the bursting pressure of the pressure relief notch 24 can be controlled within the range of 1.0±0.2 MPa, which can meet the bursting pressure requirements of the pressure relief notch 24 in most scenarios.

[0182] It can be understood that when the requirements for flatness and bursting pressure are not high, the range of h can be appropriately expanded, for example, the range of h can be expanded to h≥2a, such as h≥4 mm; or further expanded to h≥a, such as h≥2 mm.

[0183] In some embodiments, the pressure relief notch 24 includes a single step or a multi-step structure. Each step in the step structure can be, for example, a rectangle, a trapezoid, a triangle, or other regular or irregular shapes. For the pressure relief notch 24 with a multi-step structure, the multi-step structure can be produced in the process of forming the pressure relief notch 24 by multiple stampings. Specifically, in 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 step, so that the final pressure relief notch 24 is obtained through multiple molding. The multiple molding 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.

[0184] For example, as shown in FIG10 , the pressure relief notch 24 includes multiple steps 243 , and the depth of each step 243 may be the same or different. Optionally, the depth of the multiple steps 243 may gradually decrease and increase from the inside to the outside of the battery cell 20 , that is, as the number of stamping increases, the depth of each stamping increases. FIG10 is an example, and the step structure shown includes, from top to bottom, a first step 243 , a second step 243 , and a third step 243 . 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 shapes of the first step 243 and the second step 243 are rectangular, and the shape of the third step 243 is an inverted triangle.

[0185] The present application also provides a battery 100 , comprising the battery cell 20 described in any one of the above embodiments.

[0186] The present application provides an electrical device, including the battery 100 described in any of the above embodiments, and the battery 100 is used to provide electrical energy to the electrical device, such as the vehicle 1 shown in Figure 1.

[0187] From the above description, it can be seen that a pressure relief notch 24 is formed on the first wall 221 of the battery cell 20 of the embodiment of the present application, and at least one isolation groove 25 is also provided in the area between the pressure relief notch 24 and the second wall 222 on the first wall 221 to prevent the material extruded during the process of punching the pressure relief notch 24 on the first wall 221 from flowing toward the second wall 222, thereby reducing the surface defects of the second wall 222 caused by the extruded material in subsequent processes.

[0188] It should be noted that, under the premise of no conflict, the various embodiments and / or technical features in each embodiment described in this application can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the scope of protection of this application.

[0189] 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: The battery cell includes a first wall and a second wall perpendicular to the first wall, the first wall is integrally formed with a pressure relief notch, an isolation groove is provided in an area between the pressure relief notch and the second wall on the first wall, the pressure relief notch includes a main body, and the main body is opposite to the isolation groove in a direction perpendicular to the second wall, Wherein, in a direction perpendicular to the second wall, a ratio of a distance between the main body and the second wall to a size of the main body is greater than or equal to 10.

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

3. The battery cell according to claim 1 or 2, characterized in that: There are multiple isolation grooves, and the multiple isolation grooves are arranged on both sides of the pressure relief notch along a direction perpendicular to the second wall.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The opening of the isolation groove and the opening of the pressure relief notch are oriented in the same direction.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The second wall is a wall with the largest area on the battery cell.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The projection of the pressure relief notch on the first wall includes the main body extending along a first direction, and two extending parts respectively located at two ends of the main body and extending along a second direction, and the first direction intersects with 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 or 7, characterized in that: The extending portion is located at one side of the main body portion in the second direction, or the extending portion is located at both sides of the main body portion in the second direction.

9. The battery cell according to claim 8, characterized in that: 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.

10. The battery cell according to any one of claims 6 to 9, characterized in that: A dimension of the main body along the first direction is equal to a sum of dimensions of the two extensions along the second direction.

11. The battery cell according to any one of claims 1 to 5, characterized in that: The projection of the pressure relief notch on the first wall is annular.

12. The battery cell according to claim 11, characterized in that: The projection of the isolation groove on the first wall is a ring shape surrounding the pressure relief notch.

13. The battery cell according to any one of claims 1 to 12, characterized in that: The thickness of the region on the first wall where the isolation groove is located is greater than the thickness of the region on the first wall where the pressure relief notch is located.

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

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

16. The battery cell according to any one of claims 1 to 15, characterized in that: In a direction perpendicular to the second wall, a distance between a portion of the isolation groove opposite to the pressure relief notch and the second wall is greater than or equal to a size of the isolation groove.

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

18. The battery cell according to any one of claims 1 to 17, characterized in that: In a direction perpendicular to the second wall, a distance between a portion of the isolation groove opposite to the pressure relief notch and the pressure relief notch is greater than or equal to a size of the isolation groove.

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

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

21. The battery cell according to any one of claims 1 to 20, characterized in that: The battery cell comprises: Electrode assembly; a housing for accommodating the electrode assembly; and The end cover is used to cover the electrode assembly in the shell, wherein the first wall is a wall on the shell opposite to the end cover.

22. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 21.

23. An electrical device, characterized in that: Comprising a battery according to claim 22.

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