Battery cell, battery, and electric device

Abstract

The present application relates to the technical field of batteries. Disclosed in the present application are a battery cell, a battery, and an electric device. The battery cell comprises a shell and a pressure relief notch, wherein the shell is flat and comprises two first walls opposite each other in the direction of the thickness of the shell; and the pressure relief notch is arranged in at least one of the first walls. In the battery cell according to the embodiments of the present application, an area enclosed by the pressure relief notch is not limited; moreover, the pressure relief notch is also easier to process, and the manufacturing cost is reduced.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 2023116411629, filed on November 30, 2023, entitled “Battery Cell, Battery and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of battery technology, 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 an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] Batteries are widely used in portable electronic devices, electric vehicles, power tools, drones, energy storage devices, and other fields. During the battery manufacturing process, the manufacturing cost is a significant issue. Therefore, reducing battery manufacturing costs is a pressing technical challenge in battery technology.

[0006] Summary of the Invention

[0007] The present application provides a battery cell, a battery and an electrical device, wherein the pressure relief notch is provided on a large surface, so that the processing of the pressure relief notch is easier and the manufacturing cost of the battery can be reduced.

[0008] This application is achieved through the following technical solutions:

[0009] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell and a pressure relief notch. The shell is flat and comprises two first walls opposite to each other along the thickness direction of the shell. The pressure relief notch is provided on at least one of the first walls.

[0010] According to the battery cell of the embodiment of the present application, the outer shell is flat. By setting the pressure relief notch on at least one of the two first walls opposite to each other in the thickness direction of the shell, the area enclosed by the pressure relief notch is not restricted, and the area enclosed by the pressure relief notch and the setting position of the pressure relief notch can be freely selected. At the same time, since the area of ​​the outer surface of the first wall is larger, the processing of the pressure relief notch is easier and the manufacturing cost is reduced.

[0011] According to some embodiments of the present application, the pressure relief notch is a closed annular structure. In the above solution, the structural strength of the portion of the housing provided with the pressure relief notch is more uniform, and its ability to withstand high temperatures and high pressures is also improved when thermal runaway occurs in the battery cell.

[0012] According to some embodiments of the present application, the pressure relief notch is an unclosed annular structure. In the above scheme, after thermal runaway occurs in the battery cell, the crack can tear along the extension direction of the pressure relief notch. At the same time, due to the presence of the opening, the crack can tear the shell along the direction of the opening, so that the tearing direction and tearing range of the crack are controllable, achieving local valve opening, reducing the chance of large-scale shell tearing. The tearing direction and tearing range of the crack are both controllable, reducing the damage to the battery cell caused by uncontrollable cracks, and also reducing the disorderly discharge of high-pressure gas due to uncontrollable cracks and the impact on other battery cells.

[0013] According to some embodiments of the present application, the pressure relief notch is located in the center of the first wall. In the above embodiment, the area enclosed by the pressure relief notch can be selected as needed. In addition, placing the pressure relief notch in the center of the first wall can make processing easier and reduce the processing cost of the pressure relief notch.

[0014] According to some embodiments of the present application, the pressure relief notch is provided in the corner area of ​​the first wall. In the above solution, the area enclosed by the pressure relief notch is not limited. At the same time, when a battery cell experiences thermal runaway, the crack will tear the first wall along the pressure relief notch. Since the pressure relief notch is provided in the corner area of ​​the first wall, the crack can only damage the corner area of ​​the first wall, reducing the chance of the crack damaging the first wall on a large scale.

[0015] According to some embodiments of the present application, the pressure relief notch includes an arc segment, a first extension segment, and a second extension segment. The arc segment has a first end and a second end. The first extension segment extends from the first end toward the center axis of the arc segment, and the second extension segment extends from the second end toward the center axis of the arc segment. In the above scheme, after a battery cell experiences thermal runaway and the pressure relief notch is torn, a partial valve opening can be achieved, reducing the chance of large-scale tearing of the shell. The tearing direction and tearing range of the crack are both controllable, reducing damage to the battery cell caused by uncontrollable cracks, and also reducing the disorderly discharge of high-pressure gas due to uncontrollable cracks and the impact on other battery cells.

[0016] According to some embodiments of the present application, the central angle of the arc segment is α, which satisfies: 180°≤α<360°. In the above scheme, when α≥180°, the area enclosed by the arc segment is sufficient, so that when thermal runaway occurs in the battery cell, the crack tears the shell along the arc segment, and the crack on the arc segment can quickly discharge the high-pressure gas in the shell; when α<360°, the pressure relief notch is an unclosed annular structure with an opening on the pressure relief notch, so that the crack can tear the shell along the direction of the opening, making the tearing direction and tearing range of the crack controllable, thereby achieving local valve opening of the crack on the shell. When 180°≤α<360°, the crack range torn along the arc segment is sufficient, the high-pressure gas in the shell can be quickly discharged, and at the same time, the pressure relief notch has an opening, which can guide the tearing direction and tearing range of the crack, thereby achieving local valve opening of the crack on the shell.

[0017] According to some embodiments of the present application, the first extension segment is tangent to the arc segment; and / or the second extension segment is tangent to the arc segment. In the above solution, the crack on the arc segment can extend and tear very smoothly along the tangent line at the first end or the tangent line at the second end of the arc segment, reducing obstacles in the crack tearing process, making the crack tearing smoother and more controllable, and reducing stress concentration during the tearing process.

[0018] According to some embodiments of the present application, the first extension segment is a straight segment; and / or the second extension segment is a straight segment. In this solution, on the one hand, the processing of the first extension segment and / or the second extension segment is easier, and on the other hand, the tearing process of the crack on the straight segment is smoother. In other words, the straight segment can better guide the crack to tear in a predetermined direction, thereby making the tearing direction and tearing range of the crack more controllable.

[0019] According to some embodiments of the present application, the end of the first extension segment away from the arc segment and the end of the second extension segment away from the arc segment are spaced apart to form a first opening. In the above solution, the orientation of the first opening directly affects the tearing direction of the crack. For example, if the first opening is toward the corner of the first wall, then after thermal runaway of the battery cell, high-pressure gas will tear the pressure relief notch, and the crack can be torn along the direction of the first opening toward the corner, so that the tearing direction of the crack can be adjusted by adjusting the orientation of the first opening.

[0020] According to some embodiments of the present application, the pressure relief notch is provided in the corner area of ​​the first wall, and the first opening faces the corner area of ​​the first wall. In the above solution, when thermal runaway occurs in the battery cell, the crack can tear the outer shell under the guidance of the pressure relief notch. Since the pressure relief notch is provided in the corner area of ​​the first wall, the tearing area of ​​the crack is also mainly concentrated in the corner area of ​​the first wall, thereby reducing the probability of the crack damaging other areas of the first wall, making it possible to recycle the outer shell of the battery cell after thermal runaway occurs.

[0021] According to some embodiments of the present application, the pressure relief notch includes: a first arc segment and a second arc segment, the first arc segment and the second arc segment are spaced apart in the first direction, and the first arc segment and the second arc segment protrude away from each other; a first straight line segment and a second straight line segment, the first straight line segment is connected to one end of the first arc segment and the second arc segment in the same direction in the second direction, and the second straight line segment is connected to the other end of the first arc segment and the second arc segment in the same direction in the second direction, and the first direction and the second direction are perpendicular to each other.

[0022] In the above solution, the first arc segment, the first straight segment, the second arc segment and the second straight segment form a runway-shaped structure, and the first arc segment, the first straight segment, the second arc segment and the second straight segment can be sequentially etched by laser.

[0023] According to some embodiments of the present application, the length of the first straight line segment or the second straight line segment is L1, which satisfies: 1mm≤L1≤40mm. In the above scheme, when L1≥1mm, after the battery cell undergoes thermal runaway, the cracks tear the shell along the pressure relief notch, and the high-temperature and high-pressure gas in the shell can be quickly discharged. When L1≤40mm, the overall size of the pressure relief notch will not be too large, so that the overall structural strength of the shell meets the requirements. When 1mm≤L1≤40mm, the gas in the shell can be quickly discharged after the battery cell undergoes thermal runaway, and the overall structural strength of the shell also meets the requirements.

[0024] According to some embodiments of the present application, the following conditions are met: 5mm≤L1≤30mm. In the above scheme, when L1≥5mm, after thermal runaway of the battery cell occurs, the cracks tear the shell along the pressure relief notch, and the high-temperature and high-pressure gas inside the shell can be discharged more quickly. When L1≤30mm, the overall size of the pressure relief notch will not be too large, so that the overall structural strength of the shell can further meet the requirements. When 5mm≤L1≤30mm, the gas inside the shell can be discharged more quickly after thermal runaway of the battery cell occurs, and the overall structural strength of the shell can also further meet the requirements.

[0025] According to some embodiments of the present application, in the second direction, the distance between the first straight line segment and the second straight line segment is W1, which satisfies: 1mm≤W1≤40mm. In the above scheme, when W1≥1mm, after thermal runaway occurs in the battery cell, the high-temperature and high-pressure gas in the shell can be quickly discharged after the crack tears the shell along the pressure relief notch. When W1≤40mm, the overall size of the pressure relief notch will not be too large, so that the overall structural strength of the shell meets the requirements. When 1mm≤W1≤40mm, the gas in the shell can be quickly discharged after thermal runaway occurs in the battery cell, and the overall structural strength of the shell also meets the requirements.

[0026] According to some embodiments of the present application, the following conditions are met: 1mm≤W1≤10mm. In the above scheme, when W1≥1mm, after thermal runaway of the battery cell occurs, the cracks tear the shell along the pressure relief notch, and the high-temperature and high-pressure gas inside the shell can be quickly discharged. When W1≤10mm, the overall size of the pressure relief notch will not be too large, thereby further meeting the requirements for the overall structural strength of the shell. When 1mm≤W1≤10mm, the gas inside the shell can be quickly discharged after thermal runaway of the battery cell occurs, and the overall structural strength of the shell also further meets the requirements.

[0027] According to some embodiments of the present application, the first straight segment includes a first subsegment and a second subsegment, one end of the first subsegment is connected to the first arc segment, one end of the second subsegment is connected to the second arc segment, and the other end of the first subsegment and the other end of the second subsegment are spaced apart to form a second opening. In the above scheme, it is possible to partially open the valve on the side wall. When thermal runaway occurs inside the battery cell, the gas can tear the outer shell along the pressure relief notch. At the same time, the area where the second opening is located will not be disconnected from the outer shell, but will guide the gas to continue tearing the outer shell until the desired tearing effect is achieved. In other words, the second opening can guide the tearing direction of the crack, so that the tearing direction and tearing range of the crack are controllable.

[0028] According to some embodiments of the present application, the length of the pressure relief notch is L, and the distance between the first sub-segment and the second sub-segment in the first direction is L2, which satisfies: 0.05≤L2 / L≤0.8. In the above scheme, when L2 / L≥0.05, the second opening guides the crack to tear the outer shell, so that after the battery cell has a thermal runaway, the gas inside the outer shell can be quickly discharged; when L2 / L≤0.8, when the crack tears the outer shell along the direction of the second opening, the tearing range will not be too large, reducing the probability of the outer shell being damaged on a large scale. When 0.05≤L2 / L≤0.8, the gas inside the outer shell can be quickly discharged to the outside after the battery cell has a thermal runaway, while also reducing the probability of the outer shell being damaged on a large scale.

[0029] According to some embodiments of the present application, the following conditions are satisfied: 0.05≤L2 / L≤0.4. In the above solution, when L2 / L≥0.05, the second opening guides the crack to tear the outer shell, so that after the battery cell experiences thermal runaway, the gas inside the outer shell can be quickly discharged; when L2 / L≤0.4, when the crack tears the outer shell along the direction of the second opening, the tearing range will not be too large, further reducing the probability of large-scale damage to the outer shell. When 0.05≤L2 / L≤0.4, the gas inside the outer shell can be quickly discharged to the outside after the battery cell experiences thermal runaway, while also further reducing the probability of large-scale damage to the outer shell.

[0030] According to some embodiments of the present application, the housing includes a shell and a cover plate. The shell includes a bottom wall and a peripheral side wall. One end of the peripheral side wall is connected to the outer periphery of the bottom wall, and the other end of the peripheral side wall forms an opening, which is closed by the cover plate. The first wall is the cover plate or the bottom wall. In the above solution, the housing is formed by two separate components: the shell and the cover plate. The shell and the cover plate can be metal parts and can be fixed together by welding.

[0031] In a second aspect, an embodiment of the present application provides a battery comprising the above-mentioned battery cell. Since the battery according to the embodiment of the present application is provided with the above-mentioned battery cell, the battery can be processed more easily and the manufacturing cost is reduced.

[0032] In a third aspect, an embodiment of the present application provides an electrical device comprising the aforementioned battery cell or battery, wherein the battery cell or battery is used to provide electrical energy, thereby reducing the manufacturing difficulty and processing cost of the electrical device.

[0033] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] 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. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0035] FIG1 is a schematic diagram of a vehicle provided in an embodiment of the present application;

[0036] FIG2 is an exploded view of a battery provided in an embodiment of the present application;

[0037] FIG3 is an exploded view of a battery cell provided in an embodiment of the present application;

[0038] FIG4 is a schematic diagram of a first wall provided in an embodiment of the present application;

[0039] FIG5 is a partial enlarged schematic diagram of circle A in FIG4 ;

[0040] FIG6 is a schematic diagram of another first wall provided in an embodiment of the present application;

[0041] FIG7 is a schematic diagram of another first wall provided in an embodiment of the present application;

[0042] FIG8 is a partial enlarged schematic diagram of circle B in FIG7 ;

[0043] FIG9 is a schematic diagram of another first wall provided in an embodiment of the present application.

[0044] Icon: vehicle 1000, battery 100, controller 200, motor 300, case 10, battery cell 20, first sub-case 11, second sub-case 12, outer shell 21, electrode assembly 22, electrode terminal 25, shell 211, bottom wall 211a, peripheral side wall 211b, cover plate 212, first wall 212a, first edge 212a1, second edge 212a2, pressure relief notch 213, arc segment 201, first extension segment 202, second extension segment 203, central axis 201a, first opening 201c, first arc segment 204, second arc segment 205, first straight segment 206, second straight segment 207, first sub-segment 206a, second sub-segment 206b, second opening 208. DETAILED DESCRIPTION

[0045] 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 and completely 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.

[0046] 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.

[0047] 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.

[0048] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0049] 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.

[0050] The term "multiple" in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0051] 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.

[0052] 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.

[0053] 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 floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0054] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0055] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0056] The battery cells may be, but are not limited to, lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, and the like.

[0057] 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 between the positive and negative electrodes while allowing the active ions to pass through.

[0058] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0059] As an example, 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.

[0060] 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 with a silver-plated surface, stainless steel with a silver-plated surface, 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 (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0061] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used.

[0062] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0063] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, the metal foil may be silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel, or titanium.

[0064] In some embodiments, the negative electrode current collector has two opposite surfaces in its thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0065] As an example, the negative electrode active material may be a negative electrode active material for a battery that is well known in the art. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0066] In some embodiments, the separator is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical and mechanical stability can be selected.

[0067] As an example, the primary material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0068] 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.

[0069] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0070] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0071] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0072] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0073] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0074] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, or the like.

[0075] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0076] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0077] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0078] In some embodiments, the electrode assembly is a laminate structure.

[0079] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0080] In some embodiments, the housing includes an end cap and a shell. The shell has an opening, and the end cap closes the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other substances. The shell may have one or more openings. One or more end caps may also be provided.

[0081] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to a tab of the electrode assembly. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via an adapter. The electrode terminal may be provided on an end cap or on the housing.

[0082] In some embodiments, the housing is provided with an explosion-proof valve for releasing the internal pressure of the battery cell.

[0083] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. The prismatic battery cell includes a square-shell battery cell, a blade-shaped battery cell, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in the embodiments of the present application.

[0084] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0085] 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.

[0086] 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.

[0087] 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 floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0088] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0089] Batteries have outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability and low self-discharge coefficient. They are an important part of the development of new energy today.

[0090] The development of battery technology must take into account multiple design factors at the same time, such as energy density, discharge capacity, charge and discharge rate and other performance parameters. In addition, the assembly efficiency of the battery also needs to be considered.

[0091] The battery cells disclosed in the embodiments of the present application can be used, but are not limited to, in electrical equipment such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in the present application can be used to form the electrical equipment.

[0092] The embodiments of the present application provide an electrical device that uses a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, an electric bicycle, an electric motorcycle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0093] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0094] Please refer to Figure 1, which is a schematic diagram of a vehicle provided in the first embodiment of the present application. Vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can be used as an operating power source for the vehicle 1000, for the circuit system of the vehicle 1000, such as for the working power requirements during the startup, navigation and operation of the vehicle 1000.

[0095] The vehicle 1000 may further include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0096] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0097] Please refer to Figure 2, which is an exploded view of the battery provided in the first embodiment of the present application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 being housed within the housing 10. The housing 10 is used to provide a storage space for the battery cell 20, and the housing 10 can adopt a variety of structures. In some embodiments, the housing 10 can include a first sub-housing 11 and a second sub-housing 12, which cover each other and together define a storage space for accommodating the battery cell 20. The second sub-housing 12 can be a hollow structure with one end open, and the first sub-housing 11 can be a plate-like structure, with the first sub-housing 11 covering the open side of the second sub-housing 12, so that the first sub-housing 11 and the second sub-housing 12 jointly define a storage space. The first sub-housing 11 and the second sub-housing 12 can also be hollow structures with one end open, with the open side of the first sub-housing 11 covering the open side of the second sub-housing 12.

[0098] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0099] The battery cell 20 may be a secondary battery or a primary battery; the battery cell 20 may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0100] Please refer to Figure 3, which is an exploded view of a battery cell provided in some embodiments of the present application. As shown in Figure 3, a battery cell 20 includes a housing 21, an electrode assembly 22, and electrode terminals 25. Housing 21 includes a shell 211 and a cover 212. Shell 211 has an opening, and cover 212 closes the opening, isolating the internal environment of battery cell 20 from the external environment.

[0101] The housing 211 is a component used to cooperate with the cover plate 212 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 22, electrolyte, and other components. The housing 211 and the cover plate 212 can be independent components. The housing 211 can be of various shapes and sizes. Specifically, the shape of the housing 211 can be determined according to the specific shape and size of the electrode assembly 22. The housing 211 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0102] The cover plate 212 is a component that covers the opening of the housing 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover plate 212 can be adapted to the shape of the housing 211 to match the housing 211. Optionally, the cover plate 212 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the cover plate 212 from deforming when subjected to compression or collision, thereby providing the battery cell 20 with greater structural strength and improved reliability. Functional components such as electrode terminals can be provided on the cover plate 212. The electrode terminals can be used to electrically connect to the electrode assembly 22 to output or input electrical energy to the battery cell 20. The cover plate 212 can also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this is not particularly limited in the present embodiment. In some embodiments, an insulating structure can be provided on the inner side of the cover plate 212 to isolate the electrical connection components within the housing 211 from the cover plate 212 to reduce the risk of short circuits. For example, the insulating structure may be plastic, rubber, or the like.

[0103] The electrode assembly 22 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 22 may be contained in the housing 211. The electrode assembly 22 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The separator is used to separate the positive electrode sheet and the negative electrode sheet to avoid internal short circuits between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0104] In the related art, in square flat batteries, the pressure relief mechanism is generally arranged on the side wall with a narrow width. On the one hand, the electrode terminal is also provided on the side wall, and the pressure relief mechanism may have a problem of limited area in order to avoid interference with the electrode terminal. On the other hand, even if the electrode terminal is not provided on the side wall where the pressure relief mechanism is provided, the area of ​​the pressure relief mechanism will still be limited due to the overall narrowness of the side wall, resulting in poor exhaust when the battery thermal runaway occurs.

[0105] In addition, since the pressure relief mechanism is arranged on the side wall with a narrow width, it is difficult to process the pressure relief mechanism on the side wall (for example, the pressure relief notch is processed by laser etching), which leads to an increase in manufacturing costs.

[0106] To this end, the present application provides a battery cell, in which the area enclosed by the pressure relief notch is not restricted and the processing difficulty is reduced.

[0107] The battery cell according to the embodiment of the present application may include a housing 21 and a pressure relief notch 213 .

[0108] As shown in FIG3 , FIG4 and FIG7 , the housing 21 can isolate the external environment and the internal environment of the battery cell. The housing 21 can be a metal part, or an insulating part.

[0109] The housing 21 may define a receiving space, in which the electrode assembly and the electrolyte for soaking the electrode assembly may be accommodated.

[0110] The housing 21 in the embodiment of the present application is flat, and thus has a large sidewall and a small sidewall. The large sidewalls are generally two and face each other in the thickness direction of the housing 21, and the two large sidewalls are connected by the small sidewall. The flat shape of the housing 21 allows multiple battery cells to be stacked along the thickness direction, facilitating the storage and installation of multiple battery elevators.

[0111] In some embodiments of the present application, along the thickness direction of the housing 21 , the housing 21 includes two first walls 212 a opposite to each other.

[0112] It can be understood that, since the shell 21 is flat, the size of the shell 21 in the thickness direction is smaller than the size of the shell 21 in the width direction, and the size of the shell 21 in the thickness direction is smaller than the size of the shell 21 in the length direction.

[0113] The two first walls 212a face each other in the thickness direction of the housing 21. Therefore, the outer surface area of ​​the first wall 212a is larger than that of the remaining side walls. Therefore, the area enclosed by the pressure relief notch 213 provided on the first wall 212a having the largest outer surface area is not restricted, and a pressure relief notch 213 of an appropriate area can be fabricated as needed. Furthermore, providing the pressure relief notch 213 on the first wall 212a having the largest outer surface area facilitates fabrication of the pressure relief notch 213, thereby reducing the manufacturing cost of the pressure relief notch 213.

[0114] In some embodiments of the present application, the pressure relief notch 213 is provided on at least one first wall 212a. That is, only one of the two first walls 212a may be provided with the pressure relief notch 213, or both of the two first walls 212a may be provided with the pressure relief notch 213.

[0115] The structural strength of the portion of the first wall 212 a where the pressure relief notch 213 is provided is weaker than that of other portions. Therefore, after thermal runaway of the battery cell occurs, the pressure relief notch 213 will tear first, thereby quickly discharging the high-pressure gas in the housing 21 .

[0116] The pressure relief notch 213 is generally a groove structure, and the cross-sectional shape of the pressure relief notch 213 can be semicircular, trapezoidal or other shapes. This application does not limit the specific shape of the cross-sectional shape of the pressure relief notch 213.

[0117] According to the battery cell of the embodiment of the present application, the shell 21 is flat. By arranging the pressure relief notch 213 on at least one of the two first walls 212a opposite to each other in the thickness direction of the shell, the area enclosed by the pressure relief notch 213 is not restricted, and the area enclosed by the pressure relief notch 213 and the setting position of the pressure relief notch 213 can be freely selected. At the same time, since the area of ​​the outer surface of the first wall 212a is large, the processing of the pressure relief notch 213 is easier and the manufacturing cost is reduced.

[0118] In some embodiments of the present application, as shown in Figure 9 , the pressure relief notch 213 is a closed annular structure. In other words, the pressure relief notch 213 is a continuous, end-to-end structure with no openings. This provides more uniform structural strength in the portion of the housing 21 where the pressure relief notch 213 is located, improving the battery's ability to withstand high temperatures and high pressures in the event of thermal runaway.

[0119] The shape of the pressure relief notch 213 can be circular, racetrack-shaped, polygonal or other special-shaped structures. As long as it is an annular structure connected end to end, it is within the scope of protection of this application.

[0120] In some embodiments of the present application, as shown in Figures 4, 6, and 7, the pressure relief notch 213 is an unclosed annular structure. That is, the pressure relief notch 213 is not connected end to end, and the pressure relief notch 213 is spaced apart at both ends in the length direction, so that an opening is provided on the pressure relief notch 213. As a result, after thermal runaway of the battery cell occurs, the crack can be torn along the extension direction of the pressure relief notch 213. At the same time, due to the presence of the opening, the crack can tear the outer shell 21 along the direction of the opening, so that the tearing direction and tearing range of the crack are controllable, and the local valve is opened, which reduces the probability of large-scale tearing of the outer shell 21. The tearing direction and tearing range of the crack are both controllable, reducing the damage to the battery cell caused by the uncontrollable crack, and also reducing the disorderly discharge of high-pressure gas due to the uncontrollable crack and the impact on other battery cells.

[0121] In some embodiments of the present application, as shown in Figures 4 and 7 , the pressure relief notch 213 is disposed in the center of the first wall 212a. Thus, the area enclosed by the pressure relief notch 213 can be selected as needed. Furthermore, disposing the pressure relief notch 213 in the center of the first wall 212a can facilitate manufacturing and reduce the cost of manufacturing the pressure relief notch 213.

[0122] According to some embodiments of the present application, as shown in FIG6 , the pressure relief notches 213 are disposed in the corners of the first wall 212a. Thus, the area enclosed by the pressure relief notches 213 is not limited. Furthermore, when thermal runaway occurs in a battery cell, cracks tear through the first wall 212a along the pressure relief notches 213. Since the pressure relief notches 213 are disposed in the corners of the first wall 212a, the cracks can only damage the corners of the first wall 212a, reducing the chance of the cracks damaging a large area of ​​the first wall 212a.

[0123] In some embodiments of the present application, as shown in FIG5 , the pressure relief notch 213 includes an arc segment 201 . As the name implies, the arc segment 201 is not a complete circle, but an arc segment corresponding to the central angle of a circle. The central angle and radius of the arc segment 201 can be adjusted as needed.

[0124] The arc segment 201 has a first end and a second end, which are two ends of the arc segment 201 in the length direction.

[0125] The pressure relief notch 213 further includes a first extension segment 202 . The first extension segment 202 may be a straight line segment, an arc segment, or other special-shaped line segments (eg, a serpentine shape). The specific type of the first extension segment 202 is not limited herein.

[0126] The first extension segment 202 may be connected to the first end, and the first extension segment 202 may extend from the first end toward a direction close to the central axis 201 a of the arc segment 201 .

[0127] It should be noted that the central axis 201 a of the arc segment 201 can divide the arc segment 201 into two sub-arc segments, and the two sub-arc segments are symmetrical about the central axis 201 a of the arc segment 201 .

[0128] Therefore, the extension line of the first extension segment 202 extending in the direction away from the arc segment 201 will eventually intersect with the central axis 201 a of the arc segment 201 .

[0129] The pressure relief notch 213 further includes a second extension segment 203 . The second extension segment 203 may be a straight line segment, an arc segment, or other special-shaped line segments (eg, a serpentine shape). The specific type of the second extension segment 203 is not limited herein.

[0130] The second extension segment 203 may be connected to the second end, and the second extension segment 203 may extend from the second end toward a direction close to the central axis 201 a of the arc segment 201 .

[0131] Therefore, the extension line of the second extension segment 203 extending in the direction away from the arc segment 201 will eventually intersect with the central axis 201 a of the arc segment 201 .

[0132] The first extension segment 202 and the second extension segment 203 may also be symmetrical about the central axis 201a of the arc segment 201. Of course, the first extension segment 202 and the second extension segment 203 may also be asymmetrical about the central axis 201a of the arc segment 201, as long as the first extension segment 202 extends from the first end toward the direction close to the central axis 201a of the arc segment 201 and the second extension segment 203 extends from the second end toward the direction close to the central axis 201a of the arc segment 201.

[0133] According to the battery cell 20 of the embodiment of the present application, the pressure relief notch 213 includes an arc segment 201, a first extension segment 202, and a second extension segment 203. By extending the first extension segment 202 from the first end toward the direction close to the central axis 201a of the arc segment 201 and the second extension segment 203 from the second end toward the direction close to the central axis 201a of the arc segment 201, the arc segment 201 can reduce the stress concentration of the pressure relief notch 213 during processing. When thermal runaway occurs in the battery cell 20 and the internal high-pressure gas tears the pressure relief notch 213, the first extension segment 202 and the second extension segment 203 can guide the crack toward the central axis 201 close to the arc segment 201. The first extension section 202 and the second extension section 203 are close to each other in the direction of a, so that the first extension section 202 and the second extension section 203 can guide the cracks on the shell 21 to gradually converge, so that the size of the torn part of the shell 21 can be controlled. Of course, the first extension section 202 and the second extension section 203 can also make the tearing direction of the cracks controllable. Therefore, after the battery cell 20 has thermal runaway and the pressure relief notch 213 is torn, local valve opening can be achieved, reducing the probability of large-scale tearing of the shell 21. The tearing direction and tearing range of the cracks are controllable, reducing the damage to the battery cell 20 caused by the uncontrollable cracks, and also reducing the disorderly discharge of high-pressure gas due to the uncontrollable cracks and the impact on other battery cells 20.

[0134] In some embodiments of the present application, as shown in FIG5 , the central angle of the arc segment 201 is α, which satisfies the following: 180°≤α<360°. For example, the central angle can be 180°, 200°, 220°, 240°, 260°, 280°, 300°, 320°, 340°, or 350°.

[0135] The present application does not limit the specific value of the central angle of the arc segment 201, as long as the central angle of the arc segment 201 is within the above range.

[0136] When α ≥ 180°, the area enclosed by the arc segment 201 is sufficient, so that when thermal runaway occurs in the battery cell 20, the crack tears the outer shell 21 along the arc segment 201. The crack on the arc segment 201 allows the high-pressure gas in the outer shell 21 to be quickly discharged. When α < 360°, the pressure relief notch 213 is an unclosed annular structure with an opening. The crack can tear the outer shell in the direction of the opening, making the tearing direction and tearing range of the crack controllable, thereby achieving a local valve opening on the outer shell 21. When 180° ≤ α < 360°, the crack range along the arc segment 201 is sufficient, and the high-pressure gas in the outer shell 21 can be quickly discharged. At the same time, the opening on the pressure relief notch 213 can guide the tearing direction and tearing range of the crack, achieving a local valve opening on the outer shell 21.

[0137] In some embodiments of the present application, 210°≤α≤330°. For example, the central angle α of the arc segment 201 can be 210°, 240°, 245°, 250°, 255°, 260°, 265°, 270°, 275°, 280°, 285°, 290°, 295°, 300°, or 330°.

[0138] When α ≥ 210°, the area enclosed by the arc segment 201 is further increased. Thus, when thermal runaway occurs in the battery cell 20, the crack tears the outer shell 21 along the arc segment 201. The tearing range of the crack allows the high-pressure gas within the outer shell 21 to be discharged more quickly. When α ≤ 330°, the pressure relief notch 213 is an unclosed annular structure with an opening and a larger opening range. Thus, the crack can tear the outer shell along the direction of the opening. Not only is the tearing direction and tearing range of the crack controllable, but the tearing range is also larger, allowing the high-pressure gas within the outer shell 21 to be discharged more quickly. When 210° ≤ α ≤ 330°, the discharge rate of the high-pressure gas within the outer shell 21 can be further increased. At the same time, the opening size of the arc segment 201 is larger, thereby guiding the crack to tear a wider range within the outer shell 21. The opening not only guides the tearing direction and tearing range of the crack, but also further increases the discharge rate of the high-pressure gas within the outer shell 21.

[0139] In some embodiments of the present application, as shown in FIG5 , the first extension segment 202 can be tangent to the arc segment 201. In other words, the first extension segment 202 coincides with the tangent line at the first end. As a result, the crack on the arc segment 201 can smoothly extend and tear along the tangent line at the first end of the arc segment 201, reducing obstacles to the crack tearing process, making the crack tearing smoother and more controllable, and reducing stress concentration during the tearing process.

[0140] It is understandable that the first extension segment 202 can be an arc segment or a straight line segment. This application does not limit the segment type of the first extension segment 202, as long as the first extension segment 202 is tangent to the arc segment 201.

[0141] In some embodiments of the present application, as shown in FIG5 , the second extension segment 203 can be tangent to the arc segment 201. In other words, the second extension segment 203 coincides with the tangent line at the second end. As a result, the crack in the arc segment 201 can smoothly extend and tear along the tangent line at the second end of the arc segment 201, reducing obstacles to the crack tearing process, making the crack tearing smoother and more controllable, and reducing stress concentration during the tearing process.

[0142] It is understandable that the second extension segment 203 can be an arc segment or a straight line segment. This application does not limit the line segment type of the second extension segment 203, as long as the second extension segment 203 is tangent to the arc segment 201.

[0143] According to some embodiments of the present application, as shown in FIG5 , the first extension segment 202 is a straight segment. Constructing the first extension segment 202 as a straight segment can, on the one hand, make the processing of the first extension segment 202 easier, and on the other hand, make the tearing process of the crack on the straight segment smoother. In other words, the straight segment can better guide the crack to tear in a predetermined direction, thereby making the tearing direction and tearing range of the crack more controllable.

[0144] According to some embodiments of the present application, the second extension section 203 is a straight section. Constructing the second extension section 203 as a straight section can, on the one hand, make the processing of the second extension section 203 easier, and on the other hand, make the tearing process of the crack on the straight section smoother. In other words, the straight section can better guide the crack to tear in a predetermined direction, thereby making the tearing direction and tearing range of the crack more controllable.

[0145] In some embodiments of the present application, as shown in Figures 4 and 5 , the end of the first extension section 202 away from the arc section 201 and the end of the second extension section 203 away from the arc section 201 are spaced apart to form a first opening 201c. In other words, the end of the first extension section 202 away from the arc section 201 and the end of the second extension section 203 away from the arc section 201 are not connected to each other, thereby ensuring that the pressure relief notch 213 is in an unsealed state.

[0146] Generally speaking, the orientation of the first opening 201c directly affects the tearing direction of the crack. For example, if the first opening 201c is toward the corner of the first wall 212a, then after the battery cell 20 thermally runs away, the high-pressure gas will tear the pressure relief notch 213, and the crack can be torn along the direction of the first opening 201c toward the corner, so that the tearing direction of the crack can be adjusted by adjusting the orientation of the first opening 201c.

[0147] In some embodiments of the present application, as shown in FIG6 , the pressure relief notches 213 are provided in the corner regions of the first wall 212 a. By providing the pressure relief notches 213 in the corner regions of the first wall 212 a, when thermal runaway occurs in the battery cell 20, cracks can tear the outer shell 21 under the guidance of the pressure relief notches 213. Since the pressure relief notches 213 are provided in the corner regions of the first wall 212 a, the tearing areas of the cracks are also primarily concentrated in the corner regions of the first wall 212 a, thereby reducing the probability of the cracks damaging other areas of the first wall 212 a, making it possible to recycle the outer shell 21 after thermal runaway occurs in the battery cell 20.

[0148] In some embodiments of the present application, the first opening 201c on the pressure relief score 213 faces the corner of the first wall 212a. Therefore, when the crack tears the outer shell 21 along the pressure relief score 213, it can tear along the direction of the first opening 201c, and the tearing direction of the crack is toward the corner of the first wall 212a, thereby reducing the probability of the crack moving toward the middle area of ​​the first wall 212a and reducing the probability of the first wall 212a being completely torn, so that the outer shell 21 can be recycled.

[0149] In some embodiments of the present application, as shown in FIG5 , the radius of the arc segment 201 a is R, satisfying: 1 mm ≤ R ≤ 20 mm.

[0150] For example, the radius of the arc segment 201a can be 1 mm, 3 mm, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm, 15 mm, 17 mm, 19 mm, or 20 mm.

[0151] The present application does not limit the specific value of the radius of the arc segment 201a. As long as the radius of the arc segment 201a is within the above range, it is within the protection scope of the present application.

[0152] When R ≥ 1mm, the crack along the arc segment 201a can meet the pressure relief requirements of the battery cell 20 in the event of thermal runaway. When R ≤ 20mm, the arc segment 201a is not too large, thereby ensuring that the overall structural strength of the housing 21 meets the requirements. When 1mm ≤ R ≤ 20mm, the pressure relief requirements of the battery cell 20 in the event of thermal runaway are met, and the range of the pressure relief notch 213 is not too large, ensuring that the overall structural strength of the housing 21 meets the requirements.

[0153] In some embodiments of the present application, as shown in FIG4 , the length of the straight line segment is S1, which satisfies: 0<S1≤20mm. For example, the length of the straight line segment can be 1mm, 3mm, 5mm, 7mm, 9mm, 11mm, 13mm, 15mm, 17mm, 19mm, or 20mm.

[0154] It should be noted that the length of the straight segment is the length when the first extension segment 202 is configured as a straight line, or the length when the second extension segment 203 is configured as a straight line.

[0155] This application does not limit the length of the straight line segment. As long as the radius of the straight line segment is within the above range, it is within the protection scope of this application.

[0156] When S1>0, the crack tearing along the straight line segment can meet the pressure relief requirements of the battery cell 20 in the event of thermal runaway. When S1≤20mm, the straight line segment is not too large, thereby ensuring that the overall structural strength of the housing 21 meets the requirements. When 0<S1≤20mm, the pressure relief requirements of the battery cell 20 in the event of thermal runaway are met, and the range of the pressure relief notch 213 is not too large, which can affect the overall structural strength of the housing 21.

[0157] In some embodiments of the present application, 0<S1 / R≤2. For example, S1 / R can be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0.

[0158] This application does not limit the specific value of S1 / R. As long as S1 / R is within the above range, it is within the protection scope of this application.

[0159] S1 / R represents the degree to which the straight line segment extends relative to the radius of the arc segment. The larger the S1 / R, the more the straight line segment extends compared to the radius of the arc segment. The smaller the S1 / R, the less the straight line segment extends compared to the radius of the arc segment.

[0160] When S1 / R>0, a straight line segment can extend from one end of the arc segment, guiding the crack to tear the outer shell 21. Once the crack tears along the straight line segment, it can meet the pressure relief requirements of the battery cell 20 during thermal runaway. When S1 / R≤2, the length of the straight line segment is not too long, thereby controlling the range of the pressure relief notch 213 and ensuring that the overall structural strength of the outer shell 21 meets the requirements. When 0<S1 / R≤2, the straight line segment is ensured to have sufficient length to guide the tearing direction and range of the crack, while also mitigating the negative impact on the structural strength of the outer shell 21 caused by an excessively long straight line segment, resulting in an excessively large pressure relief notch 213.

[0161] According to some embodiments of the present application, as shown in FIG. 6 , the first wall 212 a includes a first edge 212 a 1 and a second edge 212 a 2 , and the first edge 212 a 1 and the second edge 212 a 2 intersect to form a corner of the first wall 212 a .

[0162] The shortest distance between the center of the pressure relief notch 213 and the first edge 212a1 is S2, and the length of the second edge 212a2 is S, satisfying: 0<S2<S / 2;

[0163] The shortest distance between the center of the pressure relief notch 213 and the second edge 212a2 is T1, and the length of the first edge 212a1 is T, satisfying: 0<T1<T / 2.

[0164] As a result, the center of the pressure relief notch 213 is close to a corner defined by the first edge 212a1 and the second edge 212a2. Consequently, the tearing area of ​​the crack is primarily concentrated in the corner area of ​​the first wall 212a, thereby reducing the probability of the crack damaging other areas of the first wall 212a and making it possible to recycle the outer shell 21 after the battery cell 20 experiences thermal runaway.

[0165] In some embodiments of the present application, as shown in Figure 6, the shortest distance between the end of the first extension segment 202 away from the arc segment 201a and the first edge 212a1 is S3, and the length of the second edge 212a2 is S, satisfying: 0<S3<S / 2; the shortest distance between the end of the second extension segment 203 away from the arc segment 201a and the second edge 212a2 is T2, and the length of the first edge 212a1 is T, satisfying: 0<T2<T / 2.

[0166] The end of the first extension section 202 away from the arc section 201a is spaced apart from the end of the second extension section 203 away from the arc section 201a to form a first opening 201c. Since the shortest distance between the end of the first extension section 202 away from the arc section 201a and the first edge 212a1 and the length of the second edge 212a2 meet the above conditions, and the shortest distance between the end of the second extension section 203 away from the arc section 201a and the second edge 212a2 and the length of the first edge 212a1 meet the above conditions, the first opening 201c faces the corner defined by the first edge 212a1 and the second edge 212a2.

[0167] Thus, when the crack tears the outer shell 21 along the pressure relief notch 213, it can tear along the direction of the first opening 201c, that is, the tearing direction of the crack is toward the corner of the first wall 212a, thereby reducing the probability of the crack moving toward the middle area of ​​the first wall 212a, reducing the probability of the first wall 212a being completely torn, and allowing the outer shell 21 to be recycled.

[0168] In some embodiments of the present application, as shown in Figures 7 to 9, the pressure relief notch 213 can be configured as a runway-shaped structure, and the pressure relief notch 213 can include a first arc segment 204, a second arc segment 205, a first straight segment 206, and a second straight segment 207. The central angles of the first arc segment 204 and the second arc segment 205 can both be 180°. The first arc segment 204 and the second arc segment 205 are spaced apart in the first direction X, and the first arc segment 204 and the second arc segment 205 protrude in a direction away from each other. In other words, the opening formed by the first arc segment 204 and the opening formed by the second arc segment 205 face each other.

[0169] The first straight line segment 206 and the second straight line segment 207 are spaced apart in the second direction Y. The first straight line segment 206 is connected to one end of the first arc segment 204 and the second arc segment 205 in the same direction in the second direction Y. The second straight line segment 207 is connected to the other end of the first arc segment 204 and the second arc segment 205 in the same direction in the second direction Y. The first direction X and the second direction Y are perpendicular to each other.

[0170] Thus, the first arc segment 204 , the first straight segment 206 , the second arc segment 205 and the second straight segment 207 form a runway-shaped structure, and the first arc segment 204 , the first straight segment 206 , the second arc segment 205 and the second straight segment 207 can be sequentially etched by laser.

[0171] In some embodiments of the present application, the length of the first straight segment 206 or the second straight segment 207 is L1, which satisfies the following: 1 mm ≤ L1 ≤ 40 mm. For example, the length of the first straight segment 206 or the second straight segment 207 can be 1 mm, 4 mm, 8 mm, 12 mm, 16 mm, 20 mm, 24 mm, 28 mm, 32 mm, 36 mm, or 40 mm. This application does not limit the specific length of the first straight segment 206 or the second straight segment 207. As long as the length of the first straight segment 206 or the second straight segment 207 meets the above range, it is within the scope of protection of this application.

[0172] When L1 ≥ 1mm, after thermal runaway of the battery cell 20 occurs, the crack along the pressure relief notch 213 tears the outer shell 21, allowing the high-temperature, high-pressure gas inside the outer shell 21 to be quickly discharged. When L1 ≤ 40mm, the overall size of the pressure relief notch 213 is not excessive, thus ensuring that the overall structural strength of the outer shell 21 meets the requirements. When 1mm ≤ L1 ≤ 40mm, the gas inside the outer shell 21 can be quickly discharged after thermal runaway of the battery cell 20 occurs, while also ensuring that the overall structural strength of the outer shell 21 meets the requirements.

[0173] In some embodiments of the present application, the length of the first straight segment 206 or the second straight segment 207 is L1, which satisfies the following: 5 mm ≤ L1 ≤ 30 mm. For example, the length of the first straight segment 206 or the second straight segment 207 can be 5 mm, 7 mm, 10 mm, 13 mm, 15 mm, 17 mm, 20 mm, 23 mm, 25 mm, 27 mm, or 30 mm. This application does not limit the specific length of the first straight segment 206 or the second straight segment 207. As long as the length of the first straight segment 206 or the second straight segment 207 meets the above range, it is within the scope of protection of this application.

[0174] When L1 ≥ 5mm, after thermal runaway of the battery cell 20 occurs, the crack along the pressure relief notch 213 tears the outer shell 21, allowing the high-temperature, high-pressure gas inside the outer shell 21 to be discharged more quickly. When L1 ≤ 30mm, the overall size of the pressure relief notch 213 is not excessively large, thereby further meeting the overall structural strength requirements of the outer shell 21. When 5mm ≤ L1 ≤ 30mm, the gas inside the outer shell 21 can be discharged more quickly after thermal runaway of the battery cell 20 occurs, while also further meeting the overall structural strength requirements of the outer shell 21.

[0175] In some embodiments of the present application, in the second direction Y, the distance between the first straight segment 206 and the second straight segment 207 is W1, which satisfies the following: 1mm≤W1≤40mm. The first straight segment 206 and the second straight segment 207 can both extend along the first direction X, so that the first straight segment 206 and the second straight segment 207 are parallel to each other. For example, the distance between the first straight segment 206 and the second straight segment 207 can be 1mm, 5mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, or 40mm. The present application does not limit the specific value of the distance between the first straight segment 206 and the second straight segment 207. As long as the distance between the first straight segment 206 and the second straight segment 207 meets the above range, it is within the scope of protection of the present application.

[0176] When W1 ≥ 1mm, after thermal runaway of the battery cell 20 occurs, the crack along the pressure relief notch 213 tears the outer shell 21, allowing the high-temperature, high-pressure gas inside the outer shell 21 to be quickly discharged. When W1 ≤ 40mm, the overall size of the pressure relief notch 213 is not excessively large, thereby ensuring that the overall structural strength of the outer shell 21 meets the requirements. When 1mm ≤ W1 ≤ 40mm, the gas inside the outer shell 21 can be quickly discharged after thermal runaway of the battery cell 20 occurs, while also ensuring that the overall structural strength of the outer shell 21 meets the requirements.

[0177] In some embodiments of the present application, in the second direction Y, the distance between the first straight segment 206 and the second straight segment 207 is W1, which satisfies the following: 1mm≤W1≤10mm. The first straight segment 206 and the second straight segment 207 can both extend along the first direction X, so that the first straight segment 206 and the second straight segment 207 are parallel to each other. For example, the distance between the first straight segment 206 and the second straight segment 207 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm. The present application does not limit the specific value of the distance between the first straight segment 206 and the second straight segment 207. As long as the distance between the first straight segment 206 and the second straight segment 207 meets the above range, it is within the scope of protection of the present application.

[0178] When W1 ≥ 1mm, after thermal runaway of the battery cell 20 occurs, the crack along the pressure relief notch 213 tears the outer shell 21, allowing the high-temperature, high-pressure gas inside the outer shell 21 to be quickly discharged. When W1 ≤ 10mm, the overall size of the pressure relief notch 213 is not excessive, thereby further meeting the overall structural strength requirements of the outer shell 21. When 1mm ≤ W1 ≤ 10mm, the gas inside the outer shell 21 can be quickly discharged after thermal runaway of the battery cell 20 occurs, while also further meeting the overall structural strength requirements of the outer shell 21.

[0179] In some embodiments of the present application, as shown in FIG8 , the first straight segment 206 includes a first subsegment 206a and a second subsegment 206b . One end of the first subsegment 206a is connected to the first arc segment 204 , and one end of the second subsegment 206b is connected to the second arc segment 205 . The other end of the first subsegment 206a is spaced apart from the other end of the second subsegment 206b to form a second opening 208 . In other words, while the pressure relief notch 213 also has a runway-shaped structure, it is not a closed runway-shaped structure. An unenclosed area is provided on the first straight segment 206 . This allows for partial valve opening on the outer shell 21 . When thermal runaway occurs within the battery cell 20 , gas can tear the outer shell 21 along the pressure relief notch 213 . Meanwhile, the area where the second opening 208 is located does not break away from the outer shell 21, but instead guides the gas to continue tearing the outer shell 21 until the desired tearing effect is achieved. In other words, the second opening 208 can guide the tearing direction of the crack, making the tearing direction and tearing range controllable.

[0180] In some embodiments of the present application, the length of the pressure relief notch 213 is L, and the distance between the first subsegment 206a and the second subsegment 206b in the first direction X is L2, satisfying the following: 0.05≤L2 / L≤0.8. For example, the ratio of the distance between the first subsegment 206a and the second subsegment 206b in the first direction X to the length of the pressure relief notch 213 may be 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, or 0.8. The present application does not limit the specific numerical value of the ratio of the distance between the first sub-segment 206a and the second sub-segment 206b in the first direction X to the length of the pressure relief notch 213. As long as the ratio of the distance between the first sub-segment 206a and the second sub-segment 206b in the first direction X to the length of the pressure relief notch 213 meets the above range, it is within the protection scope of the present application.

[0181] When L2 / L ≥ 0.05, the second opening 208 guides the crack to tear the outer shell 21, allowing the gas inside the outer shell 21 to be quickly discharged after the battery cell 20 experiences thermal runaway. When L2 / L ≤ 0.8, the crack can be kept within the outer shell 21 when it tears along the direction of the second opening 208, reducing the chance of extensive damage to the outer shell 21. When 0.05 ≤ L2 / L ≤ 0.8, the gas inside the outer shell 21 can be quickly discharged after the battery cell 20 experiences thermal runaway, while also reducing the chance of extensive damage to the outer shell 21.

[0182] In some embodiments of the present application, the length of pressure relief score 213 is L, and the distance between first subsegment 206a and second subsegment 206b in the first direction X is L2, satisfying the following: 0.05 ≤ L2 / L ≤ 0.4. For example, the ratio of the distance between first subsegment 206a and second subsegment 206b in the first direction X to the length of pressure relief score 213 can be 0.05, 0.08, 0.12, 0.16, 0.2, 0.24, 0.28, 0.32, or 0.4. This application does not limit the specific value of the ratio of the distance between first subsegment 206a and second subsegment 206b in the first direction X to the length of pressure relief score 213. As long as the ratio of the distance between first subsegment 206a and second subsegment 206b in the first direction X to the length of pressure relief score 213 meets the above range, it is within the scope of protection of this application.

[0183] When L2 / L ≥ 0.05, the second opening 208 guides the crack to tear the outer shell 21, allowing the gas inside the outer shell 21 to be quickly discharged after the battery cell 20 experiences thermal runaway. When L2 / L ≤ 0.4, the crack can be kept from tearing the outer shell 21 along the direction of the second opening 208, further reducing the probability of extensive damage to the outer shell 21. When 0.05 ≤ L2 / L ≤ 0.4, the gas inside the outer shell 21 can be quickly discharged after the battery cell 20 experiences thermal runaway, while also further reducing the probability of extensive damage to the outer shell 21.

[0184] In some embodiments of the present application, as shown in Figure 3, the housing 21 includes a shell 211 and a cover 212, the shell 211 includes a bottom wall 211a and a peripheral side wall 211b, one end of the peripheral side wall 211b is connected to the outer periphery of the bottom wall 211a, and the other end of the peripheral side wall 211b forms an opening, and the cover 212 closes the opening, wherein the first wall 212a is the cover 212 or the bottom wall 211a.

[0185] In other words, the outer shell 21 is formed from two separate components: a shell 211 and a cover plate 212. The shell 211 and cover plate 212 can be metal components and can be fixed together by welding. The first wall 212a is the cover plate 212 or the bottom wall 211a, so the pressure relief notch 201 is provided on the cover plate 212 or the bottom wall 211a. For example, if the battery cell 20 is flat and the cover plate 212 and the bottom wall 211a are opposite in the thickness direction, the pressure relief notch 201 is provided on the large surface of the outer shell 21.

[0186] In some embodiments of the present application, the housing 21 is made of stainless steel, and the pressure relief notch 201 can be formed by laser etching. Of course, the pressure relief notch 201 can also be formed by stamping, and the present application does not limit the forming method of the pressure relief notch 201.

[0187] In some embodiments of the present application, the cross-sectional shape of the pressure relief notch 201 may be a trapezoid, with the longer of the two parallel sides of the trapezoid being located at the opening 203 of the groove of the pressure relief notch 201, the shorter of the two parallel sides having a length of 0.05 mm to 1.0 mm, and the bottom angle of the trapezoid (the angle between the bottom wall and the surrounding wall of the trapezoidal groove) being 30° to 60°.

[0188] The cross section of the pressure relief notch 201 is a trapezoid, which has better consistency and less stress concentration. Of course, the cross section of the pressure relief notch 201 can also be a triangle, an arc or a rectangle.

[0189] The following briefly describes the battery of the embodiment of the present application.

[0190] The battery according to the embodiment of the present application includes the battery cell 20 of the above embodiment. Since the battery according to the embodiment of the present application is provided with the above battery cell 20, the processing of the battery is easier and the manufacturing cost is reduced.

[0191] The following briefly describes the electrical equipment in the embodiment of the present application.

[0192] The electric device according to the embodiment of the present application includes the above-mentioned battery. Since the electric device according to the embodiment of the present application is provided with the above-mentioned battery, the manufacturing difficulty and processing cost of the electric device are reduced.

[0193] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: The shell is flat and includes two first walls opposite to each other along the thickness direction of the shell; A pressure relief notch is provided on at least one of the first walls.

2. The battery cell according to claim 1, characterized in that: The pressure relief notch is a closed annular structure.

3. The battery cell according to claim 1 or 2, characterized in that: The pressure relief notch is an unclosed annular structure.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The pressure relief notch is located in a central area of ​​the first wall.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The pressure relief notch is arranged at a corner area of ​​the first wall.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The pressure relief notch includes an arc segment, a first extension segment and a second extension segment. The arc segment has a first end and a second end. The first extension segment extends from the first end toward a direction close to the central axis of the arc segment, and the second extension segment extends from the second end toward a direction close to the central axis of the arc segment.

7. The battery cell according to claim 6, characterized in that: The center angle of the arc segment is α, which satisfies: 180°≤α<360°.

8. The battery cell according to claim 6 or 7, characterized in that: The first extension segment is tangent to the circular arc segment; and / or the second extension segment is tangent to the circular arc segment.

9. The battery cell according to any one of claims 6 to 8, characterized in that: The first extension segment is a straight line segment; and / or the second extension segment is a straight line segment.

10. The battery cell according to any one of claims 6 to 9, characterized in that: One end of the first extension segment away from the arc segment and one end of the second extension segment away from the arc segment are spaced apart to form a first opening.

11. The battery cell according to claim 10, characterized in that: The pressure relief notch is disposed at a corner area of ​​the first wall, and the first opening faces the corner of the first wall.

12. The battery cell according to any one of claims 1 to 11, characterized in that: The pressure relief notch includes: a first arc segment and a second arc segment, wherein the first arc segment and the second arc segment are spaced apart in a first direction, and the first arc segment and the second arc segment protrude in a direction away from each other; A first straight line segment and a second straight line segment, wherein the first straight line segment is connected at one end of the first arc segment and the second arc segment in the same direction in the second direction, and the second straight line segment is connected at the other end of the first arc segment and the second arc segment in the same direction in the second direction, and the first direction and the second direction are perpendicular to each other.

13. The battery cell according to claim 12, characterized in that: The length of the first straight line segment or the second straight line segment is L1, which satisfies: 1mm≤L1≤40mm.

14. The battery cell according to claim 13, characterized in that: Meets: 5mm≤L1≤30mm.

15. The battery cell according to any one of claims 12 to 14, characterized in that: In the second direction, the distance between the first straight line segment and the second straight line segment is W1, which satisfies: 1 mm ≤ W1 ≤ 40 mm.

16. The battery cell according to claim 15, characterized in that: Satisfies: 1mm≤W1≤10mm.

17. The battery cell according to any one of claims 12 to 16, characterized in that: The first straight line segment includes a first subsegment and a second subsegment, one end of the first subsegment is connected to the first arc segment, one end of the second subsegment is connected to the second arc segment, and the other end of the first subsegment and the other end of the second subsegment are spaced apart to form a second opening.

18. The battery cell according to claim 17, characterized in that: The length of the pressure relief notch is L, and the distance between the first sub-segment and the second sub-segment in the first direction is L2, which satisfies: 0.05≤L2 / L≤0.

8.

19. The battery cell according to claim 18, characterized in that: Satisfies: 0.05≤L2 / L≤0.

4.

20. The battery cell according to any one of claims 1 to 19, characterized in that: The housing comprises a shell and a cover plate, the shell comprises a bottom wall and a peripheral side wall, one end of the peripheral side wall is connected to the outer peripheral edge of the bottom wall, the other end of the peripheral side wall forms an opening, and the cover plate closes the opening; The first wall is the cover plate or the bottom wall.

21. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 20.

22. An electrical equipment, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 20 or a battery according to claim 21, wherein the battery cell or the battery is used to provide electrical energy.

Images