Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device. The battery cell includes: a case including a first through hole; the electrode assembly is arranged in the shell; the pressure actuating mechanism is arranged on the shell, and the pressure actuating mechanism is configured to be capable of communicating the internal environment and the external environment of the shell when the internal pressure of the shell reaches a first threshold value P1; the temperature actuating mechanism comprises a first cover plate and a first connecting part, the first cover plate covers the first through hole, the first connecting part is connected with the first cover plate and the shell, and the first connecting part is configured to be capable of enabling P2 to be larger than or equal to P1 when the internal pressure of the shell reaches a second threshold P2, and / or the first connecting part is configured to disconnect the first cover plate and the shell when the internal temperature of the shell reaches a third threshold T1.

Description

Technical Field

[0001] 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

[0002] Batteries are widely used in electronic devices, such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0003] In battery technology, a pressure relief mechanism can be set in the battery cell to release pressure when the battery cell is in thermal runaway. For general battery cells, there is still a problem of insufficient pressure relief rate, poor battery reliability, and urgent need for improvement. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can increase the pressure relief rate of the pressure relief mechanism and improve the reliability of the battery.

[0005] In a first aspect, the present application provides a battery cell, comprising: a shell, comprising a first through hole; an electrode assembly, arranged inside the shell; a pressure actuation mechanism, arranged in the shell, the pressure actuation mechanism being configured to connect the internal environment of the shell with the external environment when the internal pressure of the shell reaches a first threshold value P1; a temperature actuation mechanism, comprising a first cover sheet and a first connecting portion, the first cover sheet covering the first through hole, the first connecting portion connecting the first cover sheet and the shell, the first connecting portion being configured to disconnect the first cover sheet and the shell when the internal pressure of the shell reaches a second threshold value P2, P2 ≥ P1, and / or the first connecting portion being configured to disconnect the first cover sheet and the shell when the internal temperature of the shell reaches a third threshold value T1.

[0006] In the scheme of the embodiment of the present application, the battery cell includes a shell, an electrode assembly, a pressure actuation mechanism and a temperature actuation mechanism, the electrode assembly is accommodated in the shell, and the shell includes a first through hole; the pressure actuation mechanism is arranged in the shell, and the pressure actuation mechanism is configured to connect the internal environment of the shell with the external environment when the internal pressure of the shell reaches a first threshold value P1, so that when the battery cell thermal runaway occurs and the internal pressure of the shell reaches P1, the pressure actuation mechanism is activated, and the internal pressure and temperature of the battery cell can be released to the outside; the temperature actuation mechanism includes a first cover sheet and a first connecting portion, the first cover sheet covers the second through hole, the first connecting portion connects the first cover sheet and the shell, and the first connecting portion is configured to connect the internal environment of the shell with the external environment when the internal pressure of the shell reaches a second threshold value P2 When P2≥P1, and / or the first connecting portion is configured to disconnect the first cover plate and the shell when the internal temperature of the shell reaches a third threshold value T1, thereby, when the battery cell thermal runaway occurs, the start time of the temperature actuation mechanism will not be earlier than that of the pressure actuation mechanism, and after the pressure actuation mechanism starts to release pressure, the internal temperature of the shell rises to the third threshold value, and the first connecting portion can disconnect the connection between the cover plate and the shell, so that the internal pressure and temperature of the battery can be released to the outside through the first through hole, thereby, when the battery cell thermal runaway occurs, the pressure actuation mechanism and the temperature actuation mechanism can release pressure at the same time to increase the pressure release speed of the battery cell, so as to reduce the risk of thermal runaway aggravated by the accumulation of pressure and temperature inside the shell, and improve the reliability of the battery cell.

[0007] In some embodiments, the first cover sheet is configured to be detachable from the housing when the internal pressure of the housing reaches a second threshold value P2, wherein P2>P1.

[0008] In the technical solution of the embodiment of the present application, the first cover plate is configured to be able to detach from the shell when the internal pressure of the shell reaches a second threshold value P2, wherein P2>P1, so that when the battery cell thermal runaways, the temperature actuation mechanism is activated later than the pressure actuation mechanism. This can not only reduce the preparation accuracy requirements of the pressure actuation mechanism, but also improve the problem that the temperature actuation mechanism is activated first, resulting in a decrease in the internal pressure of the shell and the inability to activate the pressure actuation mechanism, resulting in insufficient pressure relief rate of the battery cell.

[0009] In some embodiments, the third threshold T1 satisfies, T1 ≥ 200°C.

[0010] In the technical solution of the embodiment of the present application, the third threshold value T1 satisfies T1 ≥ 200° C., so that the first connecting portion maintains the connection between the first cover plate and the shell when the battery is at a normal temperature, thereby improving the reliability of the battery cell.

[0011] In some embodiments, the shell includes a second through hole, the first through hole and the second through hole are spaced apart, the pressure actuation mechanism includes a second cover plate and a second connecting part, the second cover plate covers the second through hole, and the second connecting part connects the second cover plate and the shell, wherein the cross-sectional area of ​​the first connecting part in its thickness direction is greater than the cross-sectional area of ​​the second connecting part in its thickness direction.

[0012] In the technical solution of the embodiment of the present application, the cross-sectional area of ​​the first connecting part in its thickness direction is larger than the cross-sectional area of ​​the second connecting part in its thickness direction, that is, the connection strength of the first connecting part is greater than the connection strength of the second connecting part, so that when the battery cell thermal runaway, the pressure resistance of the first cover piece is greater than the pressure resistance of the second cover piece, so that the pressure actuator can be separated from the shell first under the action of the internal pressure of the shell, so as to improve the problem of insufficient pressure release rate of the battery cell due to the first cover piece being separated from the shell first and the internal pressure of the shell being insufficient to start the pressure actuator mechanism.

[0013] In some embodiments, the first cover sheet is bonded to the shell via a first connection portion, and the second cover sheet is bonded to the shell via a second connection portion, or the first cover sheet and the shell are welded to form a first connection portion, and the second cover sheet and the shell are welded to form a second connection portion.

[0014] In the technical solution of the embodiment of the present application, the first cover piece and the second cover piece are both adhesively connected to the shell or the first cover piece and the second cover piece are both welded to the shell. By adjusting the bonding or welding area of ​​the first cover piece and the second cover piece, the starting sequence of the first cover piece and the second cover piece can be adjusted. The preparation difficulty is low and the reliability is high.

[0015] In some embodiments, an opening area of ​​the first through hole at one end of the outer surface of the shell is smaller than an opening area of ​​the second through hole at one end of the outer surface of the shell.

[0016] In the technical solution of the embodiment of the present application, the opening area of ​​the first through hole at one end of the outer surface of the shell is smaller than the opening area of ​​the second through hole at one end of the outer surface of the shell, so that when the battery cell thermal runaway occurs, the pressure on the first cover sheet is smaller than the pressure on the second cover sheet, so that the pressure actuator is activated before the temperature actuator, so as to improve the problem that the temperature actuator is activated first and the internal pressure of the shell is insufficient to activate the pressure actuator mechanism, resulting in insufficient pressure release rate of the battery cell.

[0017] In some embodiments, the shell includes an outer shell and a cover structure, the outer shell includes a wall panel and a chamber enclosed by the wall panel and having an opening at one end in a first direction, the cover structure covers the opening, and the first through hole is arranged at at least one end of the shell in the first direction.

[0018] In the technical solution of the embodiment of the present application, the first through hole is arranged at least at one end of the shell in the first direction to improve the problem that when the temperature actuator mechanism is activated, the high-temperature material sprayed out of the first through hole damages the normal battery cells around the thermal runaway battery cells.

[0019] In some embodiments, the second threshold value P2 satisfies, P2 ≥ 1.2 MPa.

[0020] In the technical solution of the embodiment of the present application, the second threshold value P2 satisfies P2 ≥ 1.2 MPa, so that the temperature actuation mechanism will not be activated when the battery is in normal use, thereby improving the reliability of the battery cell.

[0021] In some embodiments, the first through hole is used to inject electrolyte.

[0022] In the technical solution of the embodiment of the present application, the liquid injection hole of the battery cell can be reused as a first through hole for pressure relief, thereby improving the practicality of the battery cell.

[0023] In a second aspect, the present application provides a battery, comprising a battery cell according to any one of the embodiments of the first aspect.

[0024] In a third aspect, the present application provides an electrical device, comprising the battery of the above-mentioned second aspect embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0026] Figure 1 is a structural schematic diagram of a vehicle provided by an embodiment of the present application;

[0027] Figure 2 is a schematic diagram of the structure of a battery provided in one embodiment of the present application;

[0028] Figure 3 is a schematic structural diagram of a battery module provided in one embodiment of the application;

[0029] Figure 4 is an exploded diagram of a battery cell provided in one embodiment of the present application;

[0030] Figure 5 is a schematic structural diagram of a battery cell provided in one embodiment of the present application;

[0031] Figure 6 yes Figure 5 Bottom view of the battery cell;

[0032] Figure 7 is a schematic structural diagram of a battery cell provided in one embodiment of the present application;

[0033] Figure 8 yes Figure 5 Partial cross-sectional view at AA in the middle;

[0034] Fig. 9 is a schematic structural diagram of a battery cell provided in one embodiment of the present application;

[0035] Fig.10 An embodiment is Fig. 9 Partial cross-sectional view at the middle BB;

[0036] Fig.11 Another embodiment is Fig. 9 Partial cross-sectional view at the middle BB;

[0037] Fig.12 is a schematic structural diagram of a battery cell provided in one embodiment of the present application;

[0038] Fig.13 yes Fig.12 Bottom view of a battery cell.

[0039] Description of reference numerals:

[0040] 1. Vehicle; 101. Motor; 102. Controller; 201. Battery module;

[0041] 2. Battery; 202. Box; 2021. First box portion; 2022. Second box portion;

[0042] 3. Battery cells;

[0043] 4. Shell; 41. Shell; 42. Top cover structure; 43. First through hole; 44. Second through hole;

[0044] 5. Electrode assembly;

[0045] 6. pressure actuating mechanism; 61. second cover sheet; 62. second connecting portion;

[0046] 7. Temperature actuation mechanism; 71. First cover plate; 72. First connecting portion. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; 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" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0049] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0050] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary and should not constitute a limitation of the present application.

[0052] Any limitations.

[0053] The term "plurality" used in the present application refers to two or more (including two).

[0054] 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.

[0055] Battery cells include, 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.

[0056] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to reduce the risk of short circuit between the positive and negative electrodes, while allowing active ions to pass through.

[0057] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet 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.

[0058] 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 disposed on either or both of the two facing surfaces of the positive electrode current collector.

[0059] 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 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.).

[0060] 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 traditional materials that can be used as positive electrode active materials for batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0061] In some embodiments, the positive electrode may be a foamed metal. The foamed metal may be a nickel foam, a copper foam, an aluminum foam, an alloy foam, or a carbon foam. When the foamed metal is used as the positive electrode, the positive electrode active material may not be provided on the surface of the foamed metal, but of course, the positive electrode active material may also be provided. As an example, a lithium source material, potassium metal or sodium metal may also be filled or / and deposited in the foamed metal, and the lithium source material is lithium metal and / or a lithium-rich material.

[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 can be a metal foil, a foamed metal or a composite current collector. For example, as a metal foil, aluminum or stainless steel treated with silver, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The foamed metal can be a foamed nickel, a foamed copper, a foamed aluminum, a foamed alloy, or a foamed carbon, etc. The composite current collector can include a polymer material base and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper 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.).

[0064] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0065] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is disposed on either or both of the two facing surfaces of the negative electrode current collector.

[0066] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells 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.

[0067] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0068] In some embodiments, the separator is a separator membrane, which can be any known porous separator membrane with good chemical stability and mechanical stability.

[0069] As an example, the material of the separator may include at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or may be attached to the surface of the positive and negative electrodes.

[0070] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transmit ions and isolate the positive and negative electrodes.

[0071] In some embodiments, the battery cell further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The electrolyte can be liquid, gel or solid. Among them, the liquid electrolyte includes an electrolyte salt and a solvent.

[0072] 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 dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0073] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl 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.

[0074] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0075] 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, and the like.

[0076] 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.

[0077] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0078] 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.

[0079] In some embodiments, the electrode assembly is a laminate structure.

[0080] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets may be provided respectively, and the plurality of positive electrode sheets and the plurality of negative electrode sheets may be alternately stacked.

[0081] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0082] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded sections that are stacked.

[0083] As an example, a plurality of separators may be provided, each of which is provided between any adjacent positive electrode sheets or negative electrode sheets.

[0084] As an example, the separator may be disposed continuously, and may be disposed between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0085] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0086] In some embodiments, the electrode assembly is provided with tabs, which can lead current out of the electrode assembly. The tabs include a positive tab and a negative tab.

[0087] In some embodiments, the 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 (such as polypropylene), a composite metal housing (such as a copper-aluminum composite housing), or an aluminum-plastic film.

[0088] As an example, the battery cell may 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, a polygonal battery, such as a hexagonal battery.

[0089] 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.

[0090] 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.

[0091] In some embodiments, the battery may be a battery pack, which includes a case and battery cells, wherein the battery cells or battery modules are accommodated in the case.

[0092] 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.

[0093] In some embodiments, the battery can be an energy storage device, which includes an energy storage container, an energy storage cabinet, etc.

[0094] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, the reliability of battery cells must also be considered.

[0095] In battery technology, a pressure relief mechanism can be set in the battery cell to improve the reliability of the battery cell. The pressure relief mechanism on the battery cell has an important impact on the reliability of the battery. For example, when short circuits, overcharging, etc. occur, thermal runaway may occur inside the battery cell, resulting in a sudden increase in pressure or temperature. In this case, the internal pressure and temperature can be released outward through the pressure relief mechanism to reduce the probability of explosion and fire in the battery cell. Relevant technicians set two or more pressure relief mechanisms on the battery cell, hoping that when the battery cell thermally runs away, multiple pressure relief mechanisms can work together to increase the pressure relief rate of the battery cell. However, in the actual use of the battery cell, during thermal runaway, each pressure relief mechanism cannot operate completely, resulting in the pressure relief rate of the battery cell not meeting expectations.

[0096] This is because the pressure relief mechanism relies on thermal runaway to activate the internal pressure of the battery cell, and due to the limitation of manufacturing precision, there are some differences in the starting pressure thresholds of various pressure relief mechanisms; and due to the imbalance of internal pressure of the battery cell and other reasons, there are differences in the starting time of various pressure relief mechanisms, so that after some pressure relief mechanisms are activated, the internal pressure of the battery cell drops or the pressure rising trend slows down, resulting in the inability to start other pressure relief mechanisms, or the starting time is slow, resulting in the overall pressure relief rate of the battery cell failing to reach expectations.

[0097] Based on the above problems, an embodiment of the present application provides a battery cell, which includes a shell, an electrode assembly, a pressure actuation mechanism and a temperature actuation mechanism. The electrode assembly is accommodated in the shell, and the shell includes a first through hole; the pressure actuation mechanism is arranged in the shell, and the pressure actuation mechanism is configured to connect the internal environment of the shell and the external environment when the internal pressure of the shell reaches a first threshold value P1, so that when the battery cell thermally runs away and the internal pressure of the shell reaches P1, the pressure actuation mechanism is activated, and the internal pressure and temperature of the battery cell can be released to the outside world; the temperature actuation mechanism includes a first cover sheet and a first connecting portion, the first cover sheet covers the second through hole, the first connecting portion connects the first cover sheet and the shell, and the first connecting portion is configured to connect the internal environment of the shell and the external environment when the internal pressure of the shell reaches When the second threshold value P2, P2≥P1, and / or the first connecting portion is configured to be able to disconnect the first cover plate and the shell when the internal temperature of the shell reaches the third threshold value T1, thereby, when the battery cell thermal runaway, the start time of the temperature actuation mechanism will not be earlier than the pressure actuation mechanism, and after the pressure actuation mechanism starts to release pressure, the internal temperature of the shell rises to the third threshold value, and the first connecting portion can disconnect the connection between the cover plate and the shell, so that the internal pressure and temperature of the battery can be released to the outside through the first through hole, thereby, when the battery cell thermal runaway, the pressure actuation mechanism and the temperature actuation mechanism can release pressure at the same time to increase the pressure release speed of the battery cell, so as to reduce the risk of thermal runaway aggravated by the accumulation of pressure and temperature inside the shell, and improve the reliability of the battery cell.

[0098] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0099] The electrical device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, and the like; 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, and the like; the electric tool may include a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0100] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical equipment described above, but can also be applied to all batteries including a box and electrical equipment using the battery. However, for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0101] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1 provided for some embodiments of the present application. Vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 2 is provided inside the vehicle 1, and the battery may be provided at the bottom, head or tail of the vehicle 1. Battery 2 may be used to power the vehicle 1, for example, battery 2 may be used as an operating power source for the vehicle 1. Vehicle 1 may also include a controller 102 and a motor 101, and the controller 102 is used to control the battery to power the motor 101, for example, for starting, navigating and operating power requirements of the vehicle 1 during driving.

[0102] In some embodiments of the present application, the battery can be used not only as an operating power source for the vehicle 1 , but also as a driving power source for the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .

[0103] In order to meet different power requirements, the battery 2 may include a plurality of battery cells, and a battery cell refers to the smallest unit that constitutes a battery module or a battery pack. A plurality of battery cells can be connected in series and / or in parallel via electrode terminals for use in various applications. The battery 2 mentioned in the present application includes a battery module or a battery pack. Among them, a plurality of battery cells can be connected in series, in parallel, or in mixed connection, and mixed connection refers to a mixture of series and parallel connection. In the embodiments of the present application, a plurality of battery cells can directly constitute a battery pack, or they can first constitute a battery module, and then the battery module constitutes a battery pack.

[0104] Figure 2 A schematic structural diagram of a battery 2 according to an embodiment of the present application is shown.

[0105] like Figure 2 As shown, the battery includes a housing 202 and a battery cell (not shown), and the battery cell is accommodated in the housing 202 .

[0106] The box 202 may be a simple three-dimensional structure such as a single cuboid, cylinder or sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as cuboids, cylinders or spheres. The box 202 may be made of alloy materials such as aluminum alloy, iron alloy, polymer materials such as polycarbonate, polyisocyanurate foam plastic, or composite materials such as glass fiber and epoxy resin.

[0107] The box 202 is used to accommodate the battery cells, and the box 202 can be of various structures. In some embodiments, the box 202 can include a first box portion 2021 and a second box portion 2022, the first box portion 2021 and the second box portion 2022 cover each other, and the first box portion 2021 and the second box portion 2022 jointly define a storage space for accommodating the battery cells 3. The second box portion 2022 can be a hollow structure with one end open, the first box portion 2021 is a plate-like structure, and the first box portion 2021 covers the open side of the second box portion 2022 to form a box 202 with a storage space; the first box portion 2021 and the second box portion 2022 can also be hollow structures with one side open, and the open side of the first box portion 2021 covers the open side of the second box portion 2022 to form a box 202 with a storage space. Of course, the first box body 2021 and the second box body 2022 can be in various shapes, such as a cylinder, a cuboid, etc.

[0108] In order to improve the sealing performance after the first box body 2021 and the second box body 2022 are connected, a sealing member, such as a sealant, a sealing ring, etc., may also be provided between the first box body 2021 and the second box body 2022 .

[0109] Assuming that the first box body portion 2021 covers the top of the second box body portion 2022 , the first box body portion 2021 can also be referred to as an upper box cover, and the second box body portion 2022 can also be referred to as a lower box cover.

[0110] In the battery 2, there can be one or more battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells are connected in series and in parallel. Multiple battery cells can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells can be accommodated in the box 202; of course, multiple battery cells can also be connected in series, in parallel, or in mixed connection to form a battery module 201, and then multiple battery modules 201 can be connected in series, in parallel, or in mixed connection to form a whole, and then accommodated in the box 202.

[0111] Figure 3 A schematic structural diagram of a battery module 201 according to an embodiment of the present application is shown.

[0112] In some embodiments, Figure 2 and Figure 3 As shown, there are multiple battery cells 3, and the multiple battery cells 3 are first connected in series, parallel or mixed to form a battery module 201. The multiple battery modules 201 are then connected in series, parallel or mixed to form a whole, and are accommodated in the box 202.

[0113] The multiple battery cells 3 in the battery module 201 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 3 in the battery module 201 .

[0114] In the present application, the battery cell 3 may include a lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., which is not limited in the embodiments of the present application.

[0115] Figure 4 The schematic diagram of the structure of the battery cell 3 provided in some embodiments of the present application. The battery cell 3 refers to the smallest unit that constitutes the battery. Figure 4 The battery cell 3 includes a shell 4 and an electrode assembly 5 .

[0116] The electrode assembly 5 is a component in the battery cell 3 where electrochemical reactions occur. One or more electrode assemblies 5 may be included in the housing 4. The electrode assembly 5 is mainly formed by winding or stacking pole sheets, which are divided into positive pole sheets and negative pole sheets, and a separator is usually provided between the positive pole sheet and the negative pole sheet. The parts of the positive pole sheet and the negative pole sheet with active materials constitute the electrode body, and the parts of the positive pole sheet and the negative pole sheet without active materials each constitute a pole ear. The positive pole ear and the negative pole ear 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 active material and the negative active material react with the electrolyte, and the pole ears connect the electrode terminals to form a current loop.

[0117] The shell 4 includes an outer shell 41 and a top cover structure 42. The outer shell 41 is a component used to cooperate with the top cover structure 42 to form the internal environment of the battery cell 3, wherein the formed internal environment can be used to accommodate the electrode assembly 5, the electrolyte (not shown in the figure) and other components. The outer shell 41 and the top cover structure 42 can be independent components. An opening can be set on the outer shell 41, and the internal environment of the battery cell 3 is formed by covering the opening with the top cover structure 42 at the opening. Optionally, the top cover structure 42 and the outer shell 41 can also be integrated. Optionally, the outer shell 41 and the top cover structure 42 can form a common connection surface before other components are put into the shell, and when it is necessary to encapsulate the interior of the outer shell 41, the top cover structure 42 covers the outer shell 41. The material of the outer shell 41 can be various, and the material of the outer shell 41 can be copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0118] See also Figures 5 to 8 , Figure 5 is a schematic structural diagram of a battery cell provided in one embodiment of the present application; Figure 6 yes Figure 5 Bottom view of the battery cell; Figure 7 is a schematic structural diagram of a battery cell provided in one embodiment of the present application; Figure 8 yes Figure 5 Partial cross-sectional view at AA in the middle.

[0119] First, as Figures 5 to 8 As shown, the present application provides a battery cell 3, which includes a shell 4, an electrode assembly 5, a pressure actuation mechanism 6 and a temperature actuation mechanism 7, wherein the shell 4 includes a first through hole 43; the electrode assembly 5 is arranged inside the shell 4; the pressure actuation mechanism 6 is arranged in the shell 4, and the pressure actuation mechanism 6 is configured to connect the internal environment of the shell 4 and the external environment when the internal pressure of the shell 4 reaches a first threshold value P1; the temperature actuation mechanism 7 includes a first cover sheet 71 and a first connecting portion 72, the first cover sheet 71 covers the first through hole 43, the first connecting portion 72 connects the first cover sheet 71 and the shell 4, and the first connecting portion 72 is configured to disconnect the first cover sheet 71 and the shell 4 when the internal pressure of the shell 4 reaches a second threshold value P2, P2 ≥ P1, and / or the first connecting portion 72 is configured to disconnect the first cover sheet 71 and the shell 4 when the internal temperature of the shell 4 reaches a third threshold value T1.

[0120] In the solution of the embodiment of the present application, the battery cell 3 includes a shell 4, an electrode assembly 5, a pressure actuation mechanism 6 and a temperature actuation mechanism 7. The electrode assembly 5 is accommodated in the shell 4, and the shell 4 includes a first through hole 43; the pressure actuation mechanism 6 is arranged in the shell 4, and the pressure actuation mechanism 6 is configured to be able to connect the internal environment of the shell 4 and the external environment when the internal pressure of the shell 4 reaches a first threshold value P1, so that when the battery cell 3 thermally runs away and the internal pressure of the shell 4 reaches P1, the pressure actuation mechanism 6 is started, and the internal pressure and temperature of the battery cell 3 can be released to the outside; the temperature actuation mechanism 7 includes a first cover sheet 71 and a first connecting portion 72, the first cover sheet 71 covers the second through hole 44, the first connecting portion 72 connects the first cover sheet 71 and the shell 4, and the first connecting portion 72 is configured to be able to connect the internal environment of the shell 4 and the external environment when the internal pressure of the shell 4 reaches P1. When the temperature of the shell 4 reaches the second threshold value P2, P2 ≥ P1, and / or the first connecting portion 72 is configured to disconnect the first cover plate 71 and the shell 4 when the internal temperature of the shell 4 reaches the third threshold value T1, thereby, when the battery cell 3 thermally runs away, the start time of the temperature actuation mechanism 7 will not be earlier than the pressure actuation mechanism 6, and after the pressure actuation mechanism 6 starts to release pressure, the internal temperature of the shell 4 rises to the third threshold value, and the first connecting portion 72 can disconnect the connection between the cover plate and the shell 4, so that the internal pressure and temperature of the battery can be released to the outside through the first through hole 43, thereby, when the battery cell 3 thermally runs away, the pressure actuation mechanism 6 and the temperature actuation mechanism 7 can release pressure at the same time to increase the pressure release speed of the battery cell 3, so as to reduce the risk of thermal runaway aggravated by the accumulation of pressure and temperature inside the shell 4, and improve the reliability of the battery cell 3.

[0121] During use, the battery cell 3 may experience thermal runaway due to overcharging, piercing of the diaphragm or pole piece by a metal conductor, or piercing of the diaphragm by a dendrite. As a result, the electrolyte inside the battery cell 3 expands and volatilizes due to heat, the internal pressure of the battery cell 3 increases, and the diaphragm melts due to heat, the short-circuit area of ​​the positive and negative pole pieces increases, and the internal temperature of the battery cell 3 rises. As a result, pressure and heat will accumulate rapidly inside the battery cell 3, which may cause the battery 2 to swell and explode in severe cases.

[0122] The housing 4 includes a first through hole 43. When the battery cell 3 is in thermal runaway, the pressure and heat inside the housing 4 can be released to the outside through the first through hole 43. The size and shape of the first through hole 43 can be flexibly designed.

[0123] like Figure 5 and Figure 7 As shown, the housing 4 may be in a cubic or cylindrical shape, and the battery cell 3 may be a square-shell battery cell or a cylindrical battery cell.

[0124] The pressure actuation mechanism 6 is disposed in the housing 4. The pressure actuation mechanism 6 is configured to connect the internal environment of the housing 4 with the external environment when the internal pressure of the housing 4 reaches a first threshold value P1, which means that when the battery cell 3 is in thermal runaway and its internal pressure value P, P≥P1, the pressure actuation member is activated, and the pressure and temperature inside the housing 4 are released to the outside. When the battery cell 3 is in thermal runaway, the pressure rise rate is relatively greater than the temperature rise rate. Therefore, a pressure actuation member is disposed in the battery cell 3 to improve the response speed of the pressure relief mechanism when the battery 2 is in thermal runaway, improve the sensitivity of the pressure relief mechanism of the battery cell 3, and improve the reliability of the battery cell 3.

[0125] Exemplarily, the pressure-actuating member and the shell 4 may be matched in such a manner that the pressure-actuating member is a cover plate, the shell 4 is provided with a second through hole 44, the cover plate covers the second through hole 44 and the cover plate is welded or bonded to the shell 4; or the pressure-actuating member is a thinned area, when the internal pressure of the shell 4 reaches a first threshold value, the shell 4 is torn at the thinned area to connect the internal and external environments of the shell 4.

[0126] The temperature actuation mechanism 7 includes a first cover sheet 71 and a first connection portion 72. The first cover sheet 71 covers the first through hole 43, and the first connection portion 72 connects the first cover sheet 71 and the housing 4. Specifically, the first connection portion 72 is a colloid, and the first cover sheet 71 is connected to the housing 4 by bonding with the colloid. When the temperature inside the housing 4 reaches a third threshold, the colloid melts or inactivates, and the first cover sheet 71 is separated from the housing 4. The colloid material may be PP (Polypropylene) or PVC (Polyvinyl chloride) or PET (polyethylene terephthalate) or the like. Alternatively, the first cover sheet 71 is welded to the housing 4 to form the first connection portion 72. The first connection portion 72 may be a weld, and the first connection portion 72 may be tin, tin alloy, aluminum-tin alloy, aluminum-silicon alloy, etc. When the temperature inside the housing 4 reaches the third threshold, the first connection portion 72 melts, and the first cover sheet 71 is separated from the housing 4.

[0127] The volume of the first connection portion 72 between the first cover plate 71 and the shell 4 is adjusted to adjust the connection strength of the first connection portion 72 to the first cover plate 71 and the shell 4 so as to control the pressure start threshold of the temperature actuation mechanism 7, that is, the second threshold P2.

[0128] When the battery cell 3 thermally runs away, the internal pressure of the shell 4 first rises to the first threshold value P1, P2>P1, and the pressure actuation mechanism 6 is started. Then, when the internal temperature of the shell 4 rises to T1, the temperature actuation mechanism 7 is started, or when the internal pressure of the shell 4 rises to P2, the temperature actuation mechanism 7 is started; or the internal pressure of the shell 4 first rises to the first threshold value P1, P2=P1, and the pressure actuation mechanism 6 and the temperature actuation mechanism 7 are started at the same time.

[0129] In some embodiments, Figure 5 , Figure 6 and Figure 8 As shown, the first cover sheet 71 is configured to be able to be separated from the housing 4 when the internal pressure of the housing 4 reaches a second threshold value P2, wherein P2>P1.

[0130] In these embodiments, the first cover sheet 71 is configured to be able to detach from the shell 4 when the internal pressure of the shell 4 reaches a second threshold value P2, wherein P2>P1, so that when the battery cell 3 thermally runs away, the temperature actuation mechanism 7 is activated later than the pressure actuation mechanism 6. This can not only reduce the preparation accuracy requirements of the pressure actuation mechanism 6, but also improve the problem that the temperature actuation mechanism 7 is activated first, resulting in a decrease in the internal pressure of the shell 4 and the inability to activate the pressure actuation mechanism 6, resulting in insufficient pressure relief rate of the battery cell 3.

[0131] Considering that when P2=P1, the preparation accuracy requirements of the temperature actuation mechanism 7 and the pressure actuation mechanism 6 are high and the preparation difficulty is great; and when P2=P1, due to the uneven pressure inside the shell 4, the temperature actuation mechanism 7 may start first, and then the pressure inside the shell 4 drops, and the pressure actuation mechanism 6 may fail to start.

[0132] Therefore, in the embodiment of the present application, the first cover sheet 71 is configured to be able to detach from the shell 4 when the internal pressure of the shell 4 reaches the second threshold value P2, wherein P2>P1, so as to reduce the difficulty of preparing the battery cell 3 and improve the pressure relief reliability of the battery cell 3.

[0133] In some embodiments, Figure 5 , Figure 6 and Figure 8 As shown, the third threshold value T1 satisfies, T1 ≥ 200°C.

[0134] In these embodiments, the third threshold value T1 satisfies T1 ≥ 200° C., so that the first connection portion 72 maintains the connection between the first cover sheet 71 and the housing 4 when the battery 2 is at a normal temperature, thereby improving the reliability of the battery cell 3 .

[0135] Optionally, 200℃≤T1≤600℃, so that when the battery cell 3 is in normal use, the first connecting portion 72 will not disconnect the first cover plate 71 and the shell 4, and the first cover plate 71 can quickly disconnect the first cover plate 71 and the shell 4 when the battery cell 3 thermally runs away and its internal temperature rises, thereby improving the pressure release rate of the battery cell 3.

[0136] See also Fig. 9 and Fig.10 , Fig. 9 is a schematic structural diagram of a battery cell provided in one embodiment of the present application; Fig.10 An embodiment is Fig. 9 Partial cross-sectional view at BB in the middle.

[0137] In some embodiments, Fig. 9 and Fig.10 As shown, the shell 4 includes a second through hole 44, the first through hole 43 and the second through hole 44 are arranged at intervals, the pressure actuation mechanism 6 includes a second cover plate 61 and a second connecting portion 62, the second cover plate 61 covers the second through hole 44, and the second connecting portion 62 connects the second cover plate 61 and the shell 4, wherein the cross-sectional area of ​​the first connecting portion 72 in its thickness direction is greater than the cross-sectional area of ​​the second connecting portion 62 in its thickness direction.

[0138] In these embodiments, the cross-sectional area of ​​the first connection portion 72 in its thickness direction is greater than the cross-sectional area of ​​the second connection portion 62 in its thickness direction, that is, the connection strength of the first connection portion 72 is greater than the connection strength of the second connection portion 62, so that when the battery cell 3 thermally runs away, the pressure resistance of the first cover sheet 71 is greater than the pressure resistance of the second cover sheet 61, so that the pressure actuator can be separated from the shell 4 first under the action of the internal pressure of the shell 4, so as to improve the problem of insufficient pressure release rate of the battery cell 3 due to the first cover sheet 71 being separated from the shell 4 first and the internal pressure of the shell 4 being insufficient to start the pressure actuator mechanism 6.

[0139] The surface of the shell 4 of the battery cell 3 is provided with a first through hole 43 and a second through hole 44 at intervals. When the battery cell 3 thermally runs away, the pressure and heat inside the shell 4 can be discharged to the outside through the first through hole 43 and the second through hole 44 .

[0140] It should be clear that the size and shape of the first through hole 43 and the second through hole 44 here can be flexibly designed; the first through hole 43 and the second through hole 44 here respectively refer to two through holes covered by the pressure actuator and the temperature actuator, the number of the first through holes 43 can be one or more, and the number of the second through holes 44 can be one or more.

[0141] Exemplarily, a circular first through hole 43 and a circular second through hole 44 are arranged on the surface of the housing 4 at intervals.

[0142] In this embodiment, the first cover sheet 71 is bonded to the shell 4 through the first connecting portion 72, and the second cover sheet 61 is bonded to the shell 4 through the second connecting portion 62. The first connecting portion 72 and the second connecting portion 62 are made of the same material. The volumes of the first connecting portion 72 and the second connecting portion 62 are controlled to adjust the connection strength between the first cover sheet 71 and the second cover sheet 61 and the shell 4 so as to control the pressure threshold at which the first cover sheet 71 and the second cover sheet 61 are separated from the shell 4.

[0143] The cross-sectional area of ​​the first connection part 72 in its thickness direction is larger than the cross-sectional area of ​​the second connection part 62 in its thickness direction, that is, the contact area between the first cover piece 71 and the shell 4 and the first connection part 72 is larger than the contact area between the second cover piece 61 and the shell 4 and the second connection part 62. The connection strength of the first connection part 72 to the first cover piece 71 and the shell 4 is greater than the connection strength of the second connection part 62 to the second cover piece 61 and the shell 4.

[0144] Optionally, the first cover plate 71 and the second cover plate 61 are made of the same material to reduce the difficulty of preparing the temperature actuation mechanism 7 and the pressure actuation mechanism 6 .

[0145] In some embodiments, Fig. 9 and Fig.10 As shown, the first cover piece 71 is bonded to the shell 4 via the first connection portion 72, and the second cover piece 61 is bonded to the shell 4 via the second connection portion 62, or the first cover piece 71 and the shell 4 are welded to form the first connection portion 72, and the second cover piece 61 and the shell 4 are welded to form the second connection portion 62.

[0146] In this embodiment, the first cover piece 71 and the second cover piece 61 are both bonded to the shell 4 or the first cover piece 71 and the second cover piece 61 are both welded to the shell 4. By adjusting the bonding or welding area of ​​the first cover piece 71 and the second cover piece 61, the starting sequence of the first cover piece 71 and the second cover piece 61 can be adjusted. The preparation difficulty is low and the reliability is high.

[0147] The first connection part 72 is an adhesive layer, the first cover sheet 71 is bonded to the shell 4 through the first adhesive layer, and the second cover sheet 61 is bonded to the shell 4 through the second adhesive layer. The pressure starting threshold of the first cover sheet 71 and the second cover sheet 61 is controlled by adjusting the volume of the first adhesive layer and the second adhesive layer.

[0148] Alternatively, the first cover piece 71 and the second cover piece 61 are welded to the shell 4, the first connection portion 72 and the second connection portion 62 are welds, and the pressure start threshold of the first cover piece 71 and the second cover piece 61 is controlled by adjusting the welding connection area between the first cover piece 71 and the second cover piece 61 and the shell 4.

[0149] See also Fig.11 , Fig.11 Another embodiment is Fig. 9 Partial cross-sectional view at BB in the middle.

[0150] In some embodiments, Fig. 9 and Fig.11 As shown, the opening area of ​​the first through hole 43 at one end of the outer surface of the shell 4 is smaller than the opening area of ​​the second through hole 44 at one end of the outer surface of the shell 4 .

[0151] In this embodiment, the opening area of ​​the first through hole 43 at one end of the outer surface of the shell 4 is smaller than the opening area of ​​the second through hole 44 at one end of the outer surface of the shell 4, so that when the battery cell 3 thermally runs away, the pressure on the first cover 71 is smaller than the pressure on the second cover 61, so that the pressure actuator is activated before the temperature actuator, so as to improve the problem that the internal pressure of the shell 4 is insufficient to activate the pressure actuator mechanism 6 due to the temperature actuator being activated first, resulting in insufficient pressure release rate of the battery cell 3.

[0152] The first connection portion 72 and the second connection portion 62 are made of the same material and have the same size, so that the connection strength between the first cover sheet 71 and the housing 4 and between the second cover sheet 61 and the housing 4 is the same. Since the area of ​​the first through hole 43 is smaller than the area of ​​the second through hole 44, when the battery cell 3 is in thermal runaway, the force-bearing area of ​​the first cover sheet 71 is smaller than the force-bearing area of ​​the second cover sheet 61, and the pressure on the first cover sheet 71 is smaller than the pressure on the second cover sheet 61, so the pressure-actuated mechanism 6 can be activated before the temperature-actuated mechanism 7.

[0153] The shell 4 includes an inner surface and an outer surface which are arranged opposite to each other along the thickness direction thereof. The inner surface of the shell 4 is closer to the electrode assembly 5 than the outer surface of the shell 4 .

[0154] The shapes of the first through hole 43 and the second through hole 44 can be flexibly designed.

[0155] See also Fig.12 and Fig.13 , Fig.12 is a schematic structural diagram of a battery cell provided in one embodiment of the present application; Fig.13 yes Fig.12 Bottom view of a battery cell.

[0156] In some embodiments, Figures 5 to 7 , Fig. 9 , Fig.12 and Fig.13 As shown, the shell 4 includes an outer shell 41 and a cover structure. The outer shell 41 includes a wall plate and a chamber enclosed by the wall plate and having an opening at one end in the first direction X. The cover structure covers the opening. The first through hole 43 is set at at least one end of the shell 4 in the first direction X.

[0157] In this embodiment, the first through hole 43 is provided at least at one end of the housing 4 in the first direction X to improve the problem that when the temperature actuation mechanism 7 is activated, the high-temperature material sprayed out of the first through hole 43 damages the normal battery cells 3 around the thermal runaway battery cells 3 .

[0158] Optionally, the first through hole 43 is arranged on a cover plate structure, and the thickness of the cover plate structure is greater than the thickness of the wall plate, so as to reduce the damage of the first through hole 43 to the structural strength of the shell 4.

[0159] The housing 41 includes an opening at one or both ends in the extension direction thereof, and the cover structure covers the opening of the housing 41. When the housing 4 is provided with a cover structure, the pressure actuation mechanism 6 and the temperature actuation mechanism 7 are both provided at the cover structure. Fig. 9 As shown, one of the pressure actuation mechanism 6 and the temperature actuation mechanism 7 is arranged on the cover plate structure, and the other of the pressure actuation mechanism 6 and the temperature actuation mechanism 7 is arranged on the wall plate arranged opposite to the cover plate structure, such as Figure 5 and Figure 6 As shown, the pressure actuation mechanism 6 and the temperature actuation mechanism 7 are both arranged on the wall plate arranged opposite to the cover plate structure, such as Fig.12 and Fig.13 When the housing 4 is provided with two cover structures, the pressure actuation mechanism 6 and the temperature actuation mechanism 7 are provided in the same cover structure or in two cover structures, such as Figure 7 shown.

[0160] In some embodiments, Figure 5 , Figure 6 and Figure 8 As shown, the second threshold value P2 satisfies, P2 ≥ 1.2 MPa.

[0161] In this embodiment, the second threshold value P2 satisfies P2 ≥ 1.2 MPa, so that the temperature actuation mechanism 7 will not be activated when the battery 2 is in normal use, thereby improving the reliability of the battery cell 3 .

[0162] Optionally, if the battery cell 3 is a lithium iron phosphate battery, the second threshold value P2 satisfies, P2 ≥ 0.9 MPa; if the battery cell 3 is a ternary battery, the second threshold value P2 satisfies, P2 ≥ 1.2 MPa.

[0163] In some embodiments, Figure 5 and Figure 8 As shown, the first through hole 43 is used to inject electrolyte.

[0164] In this embodiment, the liquid injection hole of the battery cell 3 can be reused as the first through hole 43 for pressure relief, thereby improving the practicality of the battery cell 3 .

[0165] During the preparation of the battery cell 3, after the electrolyte is injected into the shell 4 through the injection hole, the first cover sheet 71 is covered on the injection hole through the first connecting portion 72 so that the injection hole is reused as the first through hole 43. There is no need to additionally open the first through hole 43 in the shell 4, which helps to improve the integrity of the shell 4 and the structural strength of the battery cell 3.

[0166] In a second aspect, the present application provides a battery, comprising a battery cell according to any one of the embodiments of the first aspect.

[0167] In a third aspect, the present application provides an electrical device, comprising the battery of the above-mentioned second aspect embodiment.

[0168] like Figures 1 to 13 As shown, the present application provides a battery cell 3, which includes a shell 4, an electrode assembly 5, a pressure actuation mechanism 6 and a temperature actuation mechanism 7. The shell 4 includes an outer shell 41 and a cover plate structure. The outer shell 41 includes a wall plate and a chamber with an opening enclosed by the wall plate. The cover plate structure covers the opening. A first through hole 43 is arranged on the cover plate structure. The first through hole 43 and the second through hole 44 are arranged at intervals. The electrode assembly 5 is arranged inside the shell 4. The pressure actuation mechanism 6 includes a second cover sheet 61 and a second connecting portion 62. The second cover sheet 61 covers the second through hole 44. The second connecting portion 62 connects the second cover sheet 61 and the shell 4. The pressure actuation mechanism 6 is configured to connect the internal environment of the shell 4 with the external environment when the internal pressure of the shell 4 reaches a first threshold value P1. The temperature actuation mechanism 7 includes a first cover sheet 71 and a first connecting portion 72. The first cover sheet 71 covers the first through hole 44. The second connecting portion 62 connects the second cover sheet 61 and the shell 4. The pressure actuation mechanism 6 is configured to connect the internal environment of the shell 4 with the external environment when the internal pressure of the shell 4 reaches a first threshold value P1. Through hole 43, the first connection part 72 connects the first cover piece 71 and the shell 4, the cross-sectional area of ​​the first connection part 72 in the thickness direction is larger than the cross-sectional area of ​​the second connection part 62 in the thickness direction, the first cover piece 71 is bonded to the shell 4 through the first connection part 72, and the second cover piece 61 is bonded to the shell 4 through the second connection part 62, or, the first cover piece 71 and the shell 4 are welded and connected to form the first connection part 72, and the second cover piece 61 and the shell 4 are welded and connected to form the second connection part 62, the first connection part 72 is configured to be able to disconnect the first cover piece 71 and the shell 4 when the internal pressure of the shell 4 reaches the second threshold value P2, P2>P1, and / or the first connection part 72 is configured to be able to disconnect the first cover piece 71 and the shell 4 when the internal temperature of the shell 4 reaches the third threshold value T1, the third threshold value T1 satisfies, T1≥200℃, and the second threshold value P2 satisfies, P2≥0.9Mpa.

[0169] In the solution of the embodiment of the present application, the battery cell 3 includes a shell 4, an electrode assembly 5, a pressure actuation mechanism 6 and a temperature actuation mechanism 7. The electrode assembly 5 is accommodated in the shell 4, and the shell 4 includes a first through hole 43; the pressure actuation mechanism 6 is arranged in the shell 4, and the pressure actuation mechanism 6 is configured to be able to connect the internal environment of the shell 4 and the external environment when the internal pressure of the shell 4 reaches a first threshold value P1, so that when the battery cell 3 thermally runs away and the internal pressure of the shell 4 reaches P1, the pressure actuation mechanism 6 is started, and the internal pressure and temperature of the battery cell 3 can be released to the outside; the temperature actuation mechanism 7 includes a first cover sheet 71 and a first connecting portion 72, the first cover sheet 71 covers the second through hole 44, the first connecting portion 72 connects the first cover sheet 71 and the shell 4, and the first connecting portion 72 is configured to be able to connect the internal environment of the shell 4 and the external environment when the internal pressure of the shell 4 reaches P1. When the second threshold value P2 is reached, P2 ≥ P1, and / or the first connecting portion 72 is configured to be able to disconnect the first cover plate 71 and the shell 4 when the internal temperature of the shell 4 reaches the third threshold value T1, thereby, when the battery cell 3 thermally runs away, the start time of the temperature actuation mechanism 7 will not be earlier than the pressure actuation mechanism 6, and after the pressure actuation mechanism 6 starts to release pressure, the internal temperature of the shell 4 rises to the third threshold value, and the first connecting portion 72 can disconnect the connection between the cover plate and the shell 4, so that the internal pressure and temperature of the battery 2 can be released to the outside through the first through hole 43, thereby, when the battery cell 3 thermally runs away, the pressure actuation mechanism 6 and the temperature actuation mechanism 7 can release pressure at the same time to increase the pressure release speed of the battery cell 3, so as to reduce the risk of thermal runaway aggravated by the accumulation of pressure and temperature inside the shell 4, and improve the reliability of the battery cell 3.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: A housing including a first through hole; An electrode assembly, disposed inside the shell; a pressure actuation mechanism, disposed in the housing, the pressure actuation mechanism being configured to be able to detach from the housing when the internal pressure of the housing reaches a first threshold value P1; The temperature actuation mechanism comprises a first cover and a first connection portion, wherein the first cover covers the first through hole, the first connection portion connects the first cover and the shell, and the first connection portion is configured to disconnect the first cover and the shell when the internal pressure of the shell reaches a second threshold value P2, P2 ≥ P1, and / or the first connection portion is configured to disconnect the first cover and the shell when the internal temperature of the shell reaches a third threshold value T1.

2. The battery cell according to claim 1, characterized in that: The first cover sheet is configured to be detachable from the housing when the internal pressure of the housing reaches a second threshold value P2, wherein P2>P1.

3. The battery cell according to claim 1, characterized in that: The third threshold value T1 satisfies T1 ≥ 200°C.

4. The battery cell according to claim 1, characterized in that: The housing includes a second through hole, the first through hole and the second through hole are spaced apart, the pressure actuation mechanism includes a second cover sheet and a second connecting portion, the second cover sheet covers the second through hole, and the second connecting portion connects the second cover sheet and the housing, Wherein, the cross-sectional area of ​​the first connecting portion in the thickness direction is greater than the cross-sectional area of ​​the second connecting portion in the thickness direction.

5. The battery cell according to claim 4, characterized in that: The first cover piece is bonded to the shell via the first connection portion, and the second cover piece is bonded to the shell via the second connection portion, or the first cover piece and the shell are welded to form the first connection portion, and the second cover piece and the shell are welded to form the second connection portion.

6. The battery cell according to claim 4, characterized in that: An opening area of ​​the first through hole at one end of the outer surface of the shell is smaller than an opening area of ​​the second through hole at one end of the outer surface of the shell.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The shell includes an outer shell and a cover plate structure, the outer shell includes a wall plate and a chamber enclosed by the wall plate and having an opening at one end in a first direction, the cover plate structure covers the opening, and the first through hole is arranged at least at one end of the shell in the first direction.

8. The battery cell according to claim 1, characterized in that: The second threshold value P2 satisfies, P2 ≥ 1.2 MPa.

9. The battery cell according to claim 1, characterized in that: The first through hole is used for injecting electrolyte.

10. A battery, characterized in that: A battery cell comprising any one of claims 1 to 9.

11. An electrical device, characterized in that: The battery comprising the battery as claimed in claim 10 above.

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