Battery monomer, battery and electric device

Abstract

The invention relates to a battery monomer, a battery and an electric device, which can reduce the influence on the surface of a shell of the battery monomer in the forming process of a pressure relief nick. The battery monomer comprises a first wall and a second wall perpendicular to the first wall, a pressure relief nick is integrally formed in the first wall, an isolation groove is formed in the area, between the pressure relief nick and the second wall, of the first wall, the pressure relief nick comprises a main body part, and the main body part is provided with a pressure relief groove; the main body part is opposite to the isolation groove in the direction perpendicular to the second wall, and in the direction perpendicular to the second wall, the ratio of the distance between the main body part and the second wall to the size of the main body part is larger than or equal to 10.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development. The battery is composed of battery cells, and the battery cells are provided with pressure relief notches to release the internal pressure. How to reduce the impact of the pressure relief notches on other parts of the battery cells during the formation process has become an urgent problem to be solved. Summary of the invention

[0003] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can reduce the impact of the pressure relief notch on the shell surface of the battery cell during the formation of the pressure relief notch.

[0004] 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, an isolation groove is provided on the first wall in an area between the pressure relief notch and the second wall, 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.

[0005] Wherein, in a 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 a 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.

[0006] The material extruded during the process of punching the pressure relief notch on the first wall of the battery cell will flow around the pressure relief notch. During the process of forming the shell by fine drawing and other processes, the material may accumulate on the second wall perpendicular to the first wall, thereby causing defects on the shell surface and affecting its flatness. In the present application, an isolation groove is provided on the first wall of the battery cell on which the pressure relief notch is provided. The isolation groove is located between the pressure relief notch and the second wall, so that the isolation groove can accommodate the material extruded during the process of making the pressure relief notch on the first wall, and prevent the material from flowing to the second wall in the subsequent process, thereby reducing the impact on the shell surface of the battery cell during the formation of the pressure relief notch.

[0007] In some possible implementations, the opening of the isolation groove and the opening of the pressure relief notch are oriented in the same direction, so that the material extruded during the process of making the pressure relief notch on the first wall can be blocked by the isolation groove in time.

[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 called the "large wall". Since the manufacturing process of the pressure relief indentation has the greatest influence on the large wall of the battery cell, arranging the isolation grooves between the pressure relief indentation and the large wall is beneficial to reducing the influence 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 portions are 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 "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.

[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 extend beyond 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 the 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 influence of the materials on the surface of the housing of the battery cell 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 notch on the first wall is annular. The annular pressure relief notch can release the 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.

[0016] In some possible implementations, the projection of the isolation groove on the first wall is a ring surrounding the pressure relief notch. Since the extruded material overflows in all directions during the process of making the annular pressure relief notch, setting the isolation groove as a ring surrounding the pressure relief notch can effectively block the material overflowing from all directions.

[0017] In some possible implementations, 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. In order 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, that is, the thickness of the region on the first wall where the isolation groove is located is greater than the thickness of the region where the pressure relief notch is located.

[0018] In some possible implementations, the thickness of the region where the isolation groove on the first wall is located is greater than or equal to the thickness of the region where the pressure relief notch on the first wall is located, and less than or equal to five times the thickness of the region where the pressure relief notch on the first wall is located; preferably, the thickness of the region where the isolation groove on the first wall is located is greater than or equal to two times the thickness of the region where the pressure relief notch on the first wall is located, and less than or equal to three times the thickness of the region where the pressure relief notch on the first wall is located. When the thickness of the region where the isolation groove on the first wall is located and the thickness of the region where the pressure relief notch on the first wall satisfy the above relationship, the influence of the isolation groove on the pressure relief function of the pressure relief notch can be reduced, and the isolation ability of the isolation groove on the extruded material will not be affected.

[0019] In some possible implementations, 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; preferably, 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 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 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.

[0021] In some possible implementations, 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; preferably, 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 the size of the isolation groove.

[0022] 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 when manufacturing the isolation groove can be reduced, thereby reducing the influence on the bursting pressure of the pressure relief notch.

[0023] In some possible implementations, the pressure relief notch includes a multi-step structure. In the process of making the pressure relief notch, the corresponding position of the first wall can be punched multiple times, each punching forms a step, and the pressure relief notch is obtained by multiple molding. The multiple molding of the pressure relief notch can reduce the particle size of the extruded material and reduce the impact on the shell surface of the battery cell.

[0024] In some possible implementations, the battery cell includes an electrode assembly, a shell and an end cap, the shell is used to accommodate the electrode assembly, and the end cap is used to cover the electrode assembly in the shell, wherein the first wall is the wall on 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 notched pressure relief notch is formed on the first wall by stamping, a shell with a pressure relief notch can be formed by a fine drawing process. Since an isolation groove is also provided on the first wall, the material extruded by stamping can be accommodated in the isolation groove, and is not easy to accumulate on the shell surface after the fine drawing process, thereby reducing the probability of defects such as bulges on the shell surface.

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

[0026] 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, wherein the battery is used to provide electrical energy to the electrical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. 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 paying creative work.

[0028] Figure 1 It is a schematic diagram of the structure of a vehicle according to an embodiment of the present application.

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

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

[0031] Figure 4 It is a side view schematic diagram of the pressure relief notch and the isolation groove according to an embodiment of the present application.

[0032] Figure 5 1 is a schematic top view of a pressure relief notch and an isolation groove according to an embodiment of the present application.

[0033] Figure 6 It is a schematic diagram of the pressure relief notch and isolation groove of another embodiment of the present application.

[0034] Figure 7 It is a schematic diagram of the pressure relief notch and isolation groove of another embodiment of the present application.

[0035] Figure 8 It is a schematic diagram of the pressure relief notch and isolation groove of another embodiment of the present application.

[0036] Fig. 9 It is a schematic diagram of the pressure relief notch and isolation groove of another embodiment of the present application.

[0037] Fig.10 It is a schematic diagram of the steps of the pressure relief notch according to an embodiment of the present application.

[0038] In the drawings, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work 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 those commonly understood by technicians in the technical field 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", "second", etc. 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 and secondary relationship.

[0041] 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.

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

[0043] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0044] The term "multiple" as used in the present 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.

[0045] In the embodiments of the present application, the battery cell may be a secondary battery, which refers to a battery cell that can be continuously used by activating the active material by charging after the battery cell is discharged. The battery cell may be, for example, a lithium-ion battery, a sodium-ion battery, a sodium-lithium-ion battery, a lithium metal battery, a sodium metal battery, a lithium-sulfur battery, a magnesium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a lead-acid battery, etc., and the embodiments of the present application are not limited thereto.

[0046] A battery cell usually includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions such as lithium ions are inserted and removed back and forth between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode to prevent the positive and negative electrodes from short-circuiting, while allowing active ions to pass through.

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

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

[0049] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. 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 and silver alloy on a polymer material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0050] 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 positive electrode active materials for batteries 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, lithium iron phosphates such as LiFePO4 (also referred to as LFP), composite materials of lithium iron phosphate and carbon, lithium manganese phosphates such as LiMnPO4, composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and at least one of composite materials of lithium iron manganese phosphate and carbon.

[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 facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0053] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. may be used. The composite current collector may include a polymer material base 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 and silver alloy on a polymer material substrate such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.

[0054] 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.

[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 the foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not be provided with a negative electrode active material.

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

[0057] 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.

[0058] The separator in the electrode assembly is disposed between the positive electrode and the negative electrode. In some embodiments, the separator is a separator. The present application does not limit the type of separator, and any porous structure separator with good chemical stability and mechanical stability can be selected. For example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic.

[0059] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0060] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The present application does not limit the type of electrolyte, which can be selected according to needs. The electrolyte can be liquid, gel or solid.

[0061] In the embodiment of the present application, the electrode assembly may be a winding structure, wherein the positive electrode sheet and the negative electrode sheet are wound to form a winding 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 sections, with a positive electrode sheet sandwiched between adjacent folded sections; or, both the positive electrode sheet and the negative electrode sheet may be folded to form a plurality of stacked folded sections.

[0062] There may be a plurality of separators, each of which is disposed between any adjacent positive electrode sheets and negative electrode sheets.

[0063] In some embodiments, the separator may be disposed continuously and disposed between any adjacent positive electrode sheets and negative electrode sheets by folding or winding.

[0064] The shape of the electrode assembly may be, for example, cylindrical, flat, or polygonal, etc. The electrode assembly may be provided with tabs, including a positive tab and a negative tab, for conducting current from the electrode assembly.

[0065] In some embodiments, the battery cell includes a shell. The shell is used to encapsulate components such as electrode assemblies and electrolytes. The shell can be a steel shell, an aluminum shell, a plastic shell such as polypropylene, a composite metal shell such as a copper-aluminum composite shell, or an aluminum-plastic film. The shell includes a box body and a cover plate.

[0066] 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 prismatic batteries, among which the polygonal prismatic batteries may be hexagonal prismatic batteries, etc. This application does not impose any restrictions on this.

[0067] The battery described in the embodiments of the present application may 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 mixed connection through a busbar.

[0068] 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.

[0069] 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 accommodated in the case.

[0070] 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.

[0071] For batteries, the main safety hazards come from the charging and discharging process. In order to improve the safety performance of the battery, a pressure relief mechanism is usually set on the battery cell. The pressure relief mechanism, for example, refers to an element or component that is activated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a predetermined threshold. The predetermined threshold can be adjusted according to different design requirements of the battery. The threshold may depend on one or more materials of the positive electrode plate, negative electrode plate, electrolyte and separator in the battery cell. The pressure relief mechanism can adopt, for example, an element or component that is sensitive to pressure or temperature, that is, when the internal pressure or temperature of the battery cell reaches the threshold, the pressure relief mechanism is activated to form a channel for internal pressure or temperature to be released. After the pressure relief mechanism is activated, the high-temperature and high-pressure substances inside the battery cell are discharged from the pressure relief mechanism to the outside of the battery cell as emissions. In this way, the battery cell can be depressurized under controllable pressure or temperature, thereby avoiding potential more serious accidents. The emissions from the battery cell include, but are not limited to, high-temperature and high-pressure gases, electrolytes, dissolved or split positive and negative pole pieces, fragments of the isolation membrane, flames, etc. produced by the reaction.

[0072] For the notch-type pressure relief mechanism, it is usually integrally formed on the shell surface of the battery cell. In the embodiment of the present 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. The material extruded during the stamping process will flow around the pressure relief notch. In the subsequent process of forming the shell by processes such as fine drawing, the material may accumulate on the shell surface of the battery cell, thereby causing defects on the shell surface and affecting its flatness.

[0073] 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 block the material extruded during the production of the pressure relief notch from flowing toward the shell surface, thereby resolving the impact of the material on the shell surface.

[0074] The technical solutions described in the embodiments of the present application are applicable to various devices that use batteries, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, for example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0075] 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 examples.

[0076] For example, Figure 1As shown, 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 arranged 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 arranged at the bottom, front or rear of the vehicle 1. The battery 100 may be used to supply power to 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.

[0077] In order to meet different power usage requirements, the battery may include multiple different types of battery cells. Multiple battery cells can be connected in series, in parallel or in a mixed manner according to the type of battery cells to form multiple battery cell groups, and the multiple battery cell groups are then connected in series to form a battery, wherein the mixed connection is a mixture of series and parallel connections. Multiple different battery cells can also be directly connected in series, in parallel or in a mixed manner to form a battery. In other words, multiple battery cells can directly form a battery, or they can first form a battery cell group according to the type of battery cells, and then form a battery from the battery cell group.

[0078] Figure 2 The schematic diagram of the structure of a battery 100 according to an embodiment of the present application is shown, and the battery 100 may include a plurality of battery cells 20. The battery 100 may also include a housing 10, the interior of the housing 10 is a hollow structure, and a plurality of battery cells are accommodated in the housing 10. The housing 10 may include two parts, which are respectively referred to as a first housing part 11 and a second housing part 12, and the first housing part 11 and the second housing part 12 are buckled together. The shapes of the first housing part 11 and the second housing part 12 may be determined according to the shapes of the combination of the plurality of battery cells, and at least one of the first housing part 11 and the second housing part 12 has an opening.

[0079] For example, Figure 2 As shown, the first box body 11 and the second box body 12 can both be hollow structures and each has only one open surface, the openings of the first box body 11 and the second box body 12 are arranged opposite to each other, and the first box body 11 and the second box body 12 are buckled together to form a box body 10 with a closed chamber. After multiple battery cells are connected in parallel, in series or in mixed series, they are placed in the box body 10 formed by the buckling of the first box body 11 and the second box body 12.

[0080] For example, unlike Figure 2As shown, only one of the first box body 11 and the second box body 12 is a hollow rectangular parallelepiped with an opening, and the other is in a plate shape to cover the opening. Taking the second box body 12 as a hollow structure with only one face as an opening face, and the first box body 11 as a plate shape as an example, the first box body 11 covers the opening of the second box body 12 to form a box body 10 with a closed chamber, which can be used to accommodate multiple battery cells. After multiple battery cells are connected in parallel, in series or in mixed series, they are placed in the box body 10 formed by buckling the first box body 11 and the second box body 12.

[0081] 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 cell. The signal transmission component may include a wiring harness board, which includes, for example, a temperature sensor and a voltage sampling line, etc., for measuring and transmitting information such as the voltage, current and temperature of the battery, and realizing safety management of the battery 100 by communicating with the BMS.

[0082] In some embodiments, the signal transmission component may also 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 cell. After 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".

[0083] As an example, Figure 3 The structural diagram of a battery cell 20 of an embodiment of the present application is shown as an example. Figure 3 As shown, the battery cell 20 includes an electrode assembly 21, a shell 22 and an end cap 23. The shell 22 is used to accommodate the electrode assembly 21, and the end cap 23 is used to cover the electrode assembly 21 in the shell 22. The end cap 23 and the shell 22 can be connected by welding or the like.

[0084] 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 .

[0085] As an example, Figure 3As shown, the first wall 221 may be a wall on the shell 22 opposite to the end cover 23, that is, the bottom wall of the shell 22. Optionally, the pressure relief notch 24 is a notch formed on the first wall 221 by an integrated molding process. For example, an integrated notch-type pressure relief notch 24 may be formed by punching on the first wall 221 by a punch press. During the punching process, the material punched out of the notch of the pressure relief notch 24 will flow to the periphery of the pressure relief notch 24. During the process of forming the shell 22 by a fine drawing process, the material may accumulate on the surface of the shell 22, for example, on the second wall 222 perpendicular to the first wall 221, causing surface defects of the shell 22, such as bulges, etc., affecting the flatness of the surface of the shell 22.

[0086] The second wall 222 may be, for example, the wall with the largest area of ​​the battery cell 20, also referred to as the "large wall". Since the pressure relief notch 24 has the greatest impact on the large wall of the battery cell 20 during the manufacturing process, the isolation groove 25 is disposed between the pressure relief notch 24 and the large wall, which is beneficial to reducing the impact on the large wall of the battery cell 20.

[0087] In the 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 block the material from flowing toward the second wall 222 in the subsequent process, thereby reducing the impact on the surface of the shell 22 of the battery cell 20.

[0088] 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 making the pressure relief notch 24 on the first wall 221 can be blocked by the isolation groove 25 in time.

[0089] In some embodiments, there are multiple isolation grooves 25, and the multiple isolation grooves 25 are arranged on both sides of the pressure relief notch 24 along a direction perpendicular to the second wall 222. In this way, the material extruded from both sides of the pressure relief notch 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 notch 24.

[0090] Optionally, the pressure relief notch 24 includes a main body portion 241, which is opposite to the isolation groove 25 in a 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.

[0091] It can be understood that the part of the pressure relief notch 24 where more extruded material is present, such as the main body 241, particularly needs to be isolated. In the direction perpendicular to the second wall 222, when 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, thereby causing surface defects of 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 enough space to flow evenly without affecting the surface of the second wall 222, so the isolation groove 25 may not be provided between the main body 241 and the second wall 222; and 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 the subsequent process, thereby affecting the second wall 222. In the direction perpendicular to the second wall 222, the larger the size of the main body 241, 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 during the manufacturing process on the second wall 222.

[0093] 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°.

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

[0095] As shown in Table 1, assuming that the dimension b of the pressure relief notch 24 in the second direction Y is 4 mm, in the cases of p / b=2, p / b=4, p / b=6, p / b=8, p / b=10, p / b=12 and p / b=14, the thickness of the second wall 222 of the test housing 22 exceeds the dimension of its standard wall thickness, i.e., the thickening value of the second wall 222. In order to improve the accuracy of the test results, 4 tests are performed, and the average value of the 4 tests can be used as the test result.

[0096] Table 1

[0097]

[0098]

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

[0100] When p / b=2, the average of the thickening values ​​obtained from 4 tests is (1.21+1.32+2.11+1.55) / 4=1.55;

[0101] 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;

[0102] 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;

[0103] 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;

[0104] 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;

[0105] 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;

[0106] When p / b=14, the average of the thickening values ​​obtained from 4 tests is (0.07+0.05+0.02+0.03) / 4=0.04.

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

[0108] 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 arranged around the pressure relief notch 24. For example, isolation grooves 25 can be arranged around the pressure relief notch 24.

[0109] 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 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 may be rectangular to reduce the process complexity of the pressure relief notch 24 and the isolation groove 25. Figure 4 and Figure 5 As shown, 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.

[0111] In other embodiments, Figures 6 to 8 As shown, 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.

[0112] 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] In the following, the battery cell 20 of the embodiment of the present application is described by 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.

[0114] In this embodiment, the pressure relief notch 24 includes a main body 241 extending along a first direction X, and two extension portions 242 respectively located at two ends of the main body 241 and extending along a 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 further improving the stability of the pressure relief notch 24.

[0115] 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.

[0116] In the case where the extension portion 242 is located on both sides of the main body portion 241 in the second direction Y, the pressure relief notch 24 is in the shape of an I-shaped character, for example, Figure 6 or Figure 7 When the extension portion 242 is located on one side of the main body portion 241 in the second direction Y, the pressure relief notch 24 is in an unclosed "mouth" shape, for example, Figure 8 shown.

[0117] 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.

[0118] Since the area between the two extensions 242 of the pressure relief notch 24 is where materials are easily accumulated during the manufacturing process of the pressure relief notch 24, the isolation groove 25 is arranged 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.

[0119] For example, Figure 6 and Figure 7 As shown, Figure 6 and Figure 7 Taking 2 isolation grooves 25 and 4 isolation grooves 25 as examples, 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.

[0120] For example, 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 notch 24. Among them, the projection of the isolation groove 25 located on the upper side of the main body 241 of the pressure relief notch 24 on the first wall 221 is located between the two extensions 242 in the first direction X, and does not exceed 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 relative to the main body 241.

[0121] Optionally, the size of the main body 241 along the first direction X is equal to the sum of the sizes of the two extension portions 242 along the second direction Y, which makes the lengths of the pressure release paths in the first direction X and the second direction Y the same, the pressure on the pressure relief notch 24 is more uniform, and the stability of the pressure relief notch 24 is improved.

[0122] 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.

[0123] In other embodiments, the projection of the pressure relief notch 24 on the first wall 221 may be annular. Optionally, the projection of the isolation groove 25 on the first wall 221 may be annular and surround the pressure relief notch 24.

[0124] For example, Fig. 9 As shown, the pressure relief notch 24 and the isolation groove 25 are both annular, and the isolation groove 25 is arranged 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 arranged to be annular to surround the pressure relief notch 24, which can effectively block the material overflowing from all directions.

[0125] Of course, in addition to providing the annular isolation groove 25 in the outer region of the pressure relief notch 24 , an annular isolation groove 25 may also be provided in the inner region of the pressure relief notch 24 at the same time.

[0126] It can be understood that the above-mentioned "ring" can be a circular or elliptical ring, and the ring can be a ring that is closed along its circumference or has a gap along its circumference. Fig. 9 Only a circular and closed ring is taken as an example, and this application does not limit this.

[0127] 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.

[0128] 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.

[0129] In the case of thermal runaway of the battery cell 20, the pressure relief notch 24 needs to be opened as soon as possible to quickly discharge the high-temperature and high-pressure waste generated inside the battery cell 20. Therefore, on the first wall 221, the thickness of the area where the pressure relief notch 24 is located should be the smallest so that it can be opened first.

[0130] 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 two times 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.

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

[0132] 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.

[0133] As an example, as shown in Table 2, Figure 6 or Figure 7Taking the “I”-shaped pressure relief notch 24 as an example, assuming that the residual thickness at the location of the pressure relief notch 24 is d=0.42 mm, the flatness of the second wall 222 of the housing 22 and the bursting pressure, i.e., the 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. In order to improve the accuracy of the test results, five tests are performed, and the average value of the five tests can be used as the test result.

[0134] Table 2

[0135]

[0136]

[0137] f is set to be greater than or equal to d, preferably greater than or equal to 2d, which can reduce the influence 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.

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

[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 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=0.86MPa;

[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=0.86MPa;

[0142] 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=1.0MPa;

[0143] 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.

[0144] 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.

[0145] It can be seen from Table 2 that 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, and the bursting pressure of the pressure relief notch 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 notch 24 in most scenarios.

[0146] 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.

[0147] 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 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.

[0148] 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.

[0149] Still Figure 4 and Figure 5 Taking the rectangular pressure relief notch 24 and the isolation groove 25 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.

[0150] 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 the subsequent process can be reduced.

[0151] As an example, as shown in Table 3, Figure 6 or Figure 7 Taking the “I”-shaped pressure relief notch 24 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 is tested under the conditions of g=2, g=4, g=6, g=8, g=10, g=12 and g=14. In order to improve the accuracy of the test results, the average value of 5 tests is taken as the test result.

[0152] Table 3

[0153]

[0154]

[0155] g is set to be greater than or equal to a, preferably, 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.

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

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

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

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

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

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

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

[0163] When 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 for the housing 22 is high, the flatness is usually required to be less than or equal to 0.2.

[0165] It can be seen from Table 3 that 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.

[0166] It can be understood that when the requirement for flatness is 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.

[0167] 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 score 24, but also prevent the material extruded during the stamping process from affecting the morphology of the pressure relief score 24, thereby reducing its influence on the bursting pressure of the pressure relief score 24. Therefore, a suitable distance must be maintained between the isolation groove 25 and the pressure relief score 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 notch 24 and the pressure relief notch 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 notch 24 and the pressure relief notch 24 is greater than or equal to three times the size of the isolation groove 25.

[0169] Still Figure 4 and Figure 5 Taking the rectangular pressure relief notch 24 and the isolation groove 25 as an example, assuming that the distance between the isolation groove 25 and the pressure relief notch 24 is h and the size of the isolation groove 2 is a in the second direction Y, then h≥a can be set, preferably, h≥3a can be set.

[0170] For the isolation groove 25 arranged between the pressure relief score 24 and the second wall 222, in the direction perpendicular to the second wall 222, an appropriate distance is maintained between the isolation groove 25 and the pressure relief score 24, 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.

[0171] As an example, as shown in Table 4, Figure 6 or Figure 7 Taking the “I”-shaped pressure relief notch 24 as an example, assuming that the dimension a of the pressure relief notch 24 in the second direction Y is 2 mm, the bursting pressure of the pressure relief notch 24 is tested under the conditions of h=1, h=2, h=3, h=4, h=5, h=6 and h=7. In order to improve the accuracy of the test results, the average value of 5 tests is taken as the test result.

[0172] Table 4

[0173]

[0174]

[0175]

[0176] h is set to be greater than or equal to a, preferably, to be greater than or equal to 3a, which can reduce the influence of the material extruded during the manufacturing process of the isolation groove 25 on the notch morphology of the pressure relief notch 24, thereby reducing the influence on the bursting pressure of the pressure relief notch 24.

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

[0178] 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;

[0179] 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;

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

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

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

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

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

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

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

[0187] 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 requirements for the bursting pressure of the pressure relief notch 24 in most scenarios.

[0188] 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.

[0189] In some embodiments, the pressure relief notch 24 includes a one-step or 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 generated 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.

[0190] For example, Fig.10 As shown, the pressure relief notch 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, as the number of stamping increases, the depth of each stamping increases. Fig.10 As an example, 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, 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.

[0191] The present application also provides a battery 100 , comprising the battery cell 20 described in any one of the above embodiments.

[0192] The present 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, the electrical device is, for example, Figure 1 The vehicle 1 is shown.

[0193] 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, so as to prevent the material extruded during the process of stamping 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.

[0194] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0195] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present 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, 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: The battery according to claim 22 is used to provide electrical energy to the electrical device.

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