Battery monomer, battery and electric equipment

Abstract

The invention provides a battery monomer, a battery and electric equipment. The battery cell includes an electrode assembly, a housing, and an insulator. The shell is used for containing the electrode assembly and provided with a wall part, the wall part is provided with a first pressure relief area, and the first pressure relief area is used for being opened when the battery monomers are in thermal runaway. The insulator is at least partially disposed between the electrode assembly and the wall portion to insulate and isolate the electrode assembly from the wall portion. Wherein a second pressure relief area is arranged at the position, corresponding to the first pressure relief area, of the insulating part, and the second pressure relief area is used for allowing gas to pass through the insulating part to reach the first pressure relief area when the single battery is in thermal runaway. According to the battery monomer, the insulating part is arranged between the wall part and the electrode assembly, so that the wall part and the electrode assembly can be insulated and isolated, and the safety of the battery monomer is improved. And when the single battery is in thermal runaway, the second pressure relief area allows gas to pass through the insulating part to release pressure from the first pressure relief area, so that the safety is relatively high.

Description

Battery cells, batteries and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the international patent application entitled “Battery Cell, Battery and Electrical Equipment” filed on August 25, 2022 (application number: PCT / CN2022 / 114890), the entire contents of which are incorporated herein by reference. Technical Field

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

[0004] Batteries are widely used in new energy applications, such as electric vehicles and new energy vehicles. These have become a new trend in the automotive industry. The development of battery technology requires consideration of multiple design factors, including performance parameters such as battery life, energy density, discharge capacity, and charge / discharge rate. Furthermore, battery safety must be considered. However, current battery safety is relatively poor.

[0005] Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a battery cell, a battery, and an electrical device, which are intended to improve the problem of poor battery safety in the related art.

[0007] In a first aspect, an embodiment of the present application provides a battery cell, comprising an electrode assembly, a shell and an insulating member, wherein the shell is used to accommodate the electrode assembly, and the shell has a wall portion; the wall portion is provided with a first pressure relief area, and the first pressure relief area is used to open when the battery cell thermally runs away; the insulating member is at least partially provided between the electrode assembly and the wall portion to insulate and isolate the electrode assembly and the wall portion; wherein a second pressure relief area is provided at a position of the insulating member corresponding to the first pressure relief area, and the second pressure relief area is used to allow gas to pass through the insulating member to reach the first pressure relief area when the battery cell thermally runs away.

[0008] In the above technical solution, an insulating member is installed between the electrode assembly of the battery cell and the wall portion where the first pressure relief area is located. This insulates the wall portion from the electrode assembly, enhancing the safety of the battery cell. The insulating member includes a second pressure relief area corresponding to the first pressure relief area. In the event of thermal runaway of the battery cell due to pressure relief, the second pressure relief area allows gas to pass through the insulating member and release pressure from the first pressure relief area, providing a higher level of safety.

[0009] As an optional technical solution of an embodiment of the present application, the second pressure relief area is configured to open when the battery cell experiences thermal runaway.

[0010] In the above technical solution, when the battery cell is in normal use, the second pressure relief area separates the electrode assembly from the first pressure relief area. Even if the battery cell is vibrated, the electrolyte in the shell is not likely to flush the first pressure relief area and affect the detonation pressure of the first pressure relief area.

[0011] As an optional technical solution of an embodiment of the present application, the wall portion is provided with a pressure relief groove, and the first pressure relief area is used to open along the pressure relief groove when the battery cell thermally runs away; along the first direction, the insulating member is arranged opposite to the wall portion, and the projection of the insulating member covers the pressure relief groove.

[0012] In the above technical solution, the pressure relief groove is a relatively weak point on the wall. In the event of thermal runaway of the battery cell, the first pressure relief area will open along the pressure relief groove. By having the projection of the insulating member along the first direction cover the pressure relief groove, the electrolyte is less likely to flush the pressure relief groove and affect the detonation pressure of the first pressure relief area.

[0013] As an optional technical solution of an embodiment of the present application, along the first direction, the projection of the second pressure relief area covers the projection of the first pressure relief area.

[0014] In the above technical solution, by making the projection of the second pressure relief area along the first direction cover the projection of the first pressure relief area, the electrolyte is not easy to flush the first pressure relief area and is not easy to affect the detonation pressure of the first pressure relief area.

[0015] As an optional technical solution of an embodiment of the present application, along the first direction, the projection of the second pressure relief area covers the pressure relief groove.

[0016] In the above technical solution, the projection of the second pressure relief area along the first direction covers the pressure relief groove. When the battery cell is in normal use, the second pressure relief area can block the electrolyte, reducing the risk of electrolyte flushing the pressure relief groove. In the event of thermal runaway of the battery cell, the second pressure relief area opens, allowing gas to reach the pressure relief groove more quickly, causing the bottom wall of the pressure relief groove to rupture in time, thereby achieving rapid pressure relief and improving the safety of the battery cell.

[0017] As an optional technical solution of the embodiment of the present application, the insulating member is provided with a weak area, and the weak area is provided along the edge of the second pressure relief area.

[0018] In the above technical solution, by providing a weak area on the insulating member, the second pressure relief area can be opened from the weak area in the event of thermal runaway of the battery cell. Because the weak area is provided along the edge of the second pressure relief area, the second pressure relief area will open along the edge in the event of thermal runaway of the battery cell, providing a larger opening for gas to pass through.

[0019] As an optional technical solution of the embodiment of the present application, the weak area is arranged around the outside of the projection of the first pressure relief area on the insulating member along the first direction.

[0020] In the above technical solution, because the weak zone is located along the edge of the second pressure relief area and surrounds the outer side of the projection of the first pressure relief area on the insulating member along the first direction, the second pressure relief area is larger than the first pressure relief area. In other words, along the first direction, the projection of the second pressure relief area on the wall overlaps the first pressure relief area. This allows for smoother pressure relief when a battery cell experiences thermal runaway.

[0021] As an optional technical solution of an embodiment of the present application, the pressure relief groove is opened on the wall portion, the pressure relief groove is arranged along the edge of the first pressure relief area, and the weak area is arranged around the outside of the projection of the pressure relief groove on the insulating part along the first direction.

[0022] In the above technical solution, by providing a pressure relief groove on the wall, a weak point is formed, which facilitates the opening of the first pressure relief area from the weak point when the battery cell experiences thermal runaway. Because the pressure relief groove is provided along the edge of the first pressure relief area, when the battery cell experiences thermal runaway, the first pressure relief area will open along the edge, providing a larger opening for gas to pass through.

[0023] As an optional technical solution of an embodiment of the present application, the battery cell includes a pressure relief piece, a pressure relief hole is opened on the wall portion, the pressure relief piece covers the pressure relief hole, the pressure relief groove is opened on the pressure relief piece, and the notch is arranged around the outside of the projection of the pressure relief groove on the insulating piece along the first direction.

[0024] In the above technical solution, a pressure relief groove is provided on the pressure relief member to form a weak position, so that the first pressure relief area can be opened from the weak position when the battery cell experiences thermal runaway.

[0025] As an optional technical solution of the embodiment of the present application, the weak area is arranged around the outside of the projection of the pressure relief hole on the insulating member along the first direction.

[0026] In the above technical solution, by surrounding the weakened area outside the projection of the pressure relief hole on the insulating member along the first direction, if the weakened area penetrates the insulating member, during normal use of the battery cell, the electrolyte will not flow directly to the pressure relief member after passing through the weakened area. Instead, it will first collide with the wall and change its flow direction, reducing the impact force before flowing to the pressure relief member. This makes the pressure relief member less susceptible to electrolyte erosion. In addition, in the event of thermal runaway of the battery cell, the area of ​​the second pressure relief area opened is larger than that of the pressure relief hole, facilitating smooth pressure relief.

[0027] As an optional technical solution of an embodiment of the present application, the weak area includes a plurality of weak segments, and the plurality of weak segments are arranged at intervals along the circumference of the second pressure relief area.

[0028] In the above technical solution, by providing multiple weak sections, the second pressure relief area can be opened at the locations of the multiple weak sections in the event of thermal runaway of a battery cell, allowing gas to release pressure from the first pressure relief area through the insulating member. Because the multiple weak sections are spaced circumferentially along the second pressure relief area, the area between adjacent weak sections acts as a reinforcing rib, providing increased strength. Even if the battery cell is subjected to significant vibration, the second pressure relief area will not accidentally open.

[0029] As an optional technical solution of the embodiment of the present application, the weak section is in a strip shape, and the width of the weak section is D1, satisfying: D1≤2mm.

[0030] In the above technical solution, the width of the weak section is less than 2mm, which actually limits the width of the remaining portion between two adjacent weak sections. The smaller the width of this portion, the easier it is for the second pressure relief area to open in the event of thermal runaway of the battery cell. If D1 > 2mm, the width of the remaining portion between two adjacent weak sections is also greater than 2mm. This width is too large, and the second pressure relief area cannot open in time in the event of thermal runaway of the battery cell, preventing the battery cell from relieving pressure in time.

[0031] As an optional technical solution of an embodiment of the present application, along the circumference of the second pressure relief area, the distance between two adjacent weak sections is D2, satisfying: D2≤10mm.

[0032] In the above technical solution, the distance between two adjacent weak sections is the length of the remaining portion between the two adjacent weak sections. The smaller the length of this portion, the easier it is for the second pressure relief area to open in the event of thermal runaway of the battery cell. If D2 is greater than 10mm, the length of the remaining portion between the two adjacent weak sections is also greater than 10mm. This length is too large, and the second pressure relief area may not open in time in the event of thermal runaway of the battery cell, preventing the battery cell from releasing pressure in time.

[0033] As an optional technical solution of an embodiment of the present application, in a direction perpendicular to the first direction, a distance between the weak area and the first pressure relief area is D3, satisfying: D3≤3mm.

[0034] In the above technical solution, by limiting the distance between the weak zone and the first pressure relief area in a direction perpendicular to the first direction, the area relationship between the second pressure relief area and the first pressure relief area is effectively limited. The area of ​​the second pressure relief area is larger than that of the first pressure relief area, but the area of ​​the second pressure relief area cannot be too large. Otherwise, when the second pressure relief area is opened, the second pressure relief area separates from the insulating member, and the separated part may fall into the first pressure relief area, thereby blocking the first pressure relief area and affecting the pressure relief of the first pressure relief area.

[0035] As an optional technical solution of an embodiment of the present application, the weak area is a closed structure extending along a closed trajectory.

[0036] In the above technical solution, the weak area is arranged along the entire circumference of the edge of the second pressure relief area, so that the second pressure relief area is easily opened when the battery cell experiences thermal runaway.

[0037] As an optional technical solution of the embodiment of the present application, notches, grooves or through holes are provided on the insulating member to form the weak area.

[0038] In the above technical solution, notches and grooves are provided in the insulating member to reduce the thickness of the insulating member, forming a weak point, which facilitates cracking during thermal runaway of the battery cell. Multiple through holes can be provided in the insulating member, making it easier to break between two adjacent through holes, thus facilitating cracking during thermal runaway of the battery cell.

[0039] As an optional technical solution of the embodiment of the present application, the melting point of the weak area is lower than the melting point of the insulating member.

[0040] In the above technical solution, when the battery cell thermally runs away, the temperature of the gas is high, and the high-temperature gas will melt the weak area, thereby opening the second pressure relief area and allowing the gas to pass through the insulating member to reach the first pressure relief area.

[0041] As an optional technical solution of an embodiment of the present application, a notch, a groove or a through hole is provided on the insulating member, and the notch, the groove or the through hole is filled with a filler, and the melting point of the filler is lower than the melting point of the insulating member.

[0042] In the above technical solution, by providing notches or grooves on the insulating member, the insulating member is thinned to form a weak point, which facilitates cracking during thermal runaway of the battery cell. By providing through holes on the insulating member, multiple through holes can be provided, so that the gaps between two adjacent through holes are easily broken, which facilitates cracking during thermal runaway of the battery cell. Filling the insulating member into the notches, grooves or through holes makes it difficult for the electrolyte to enter the notches or grooves, or for the electrolyte to flow through the through holes to the wall. In this way, the electrolyte in the battery cell can all penetrate the electrode assembly, which reduces the waste of electrolyte.

[0043] As an optional technical solution of an embodiment of the present application, a notch or groove is provided on the insulating member to form the weak area, and the insulating member has a first surface facing the wall portion, and the notch or groove is provided on the first surface.

[0044] In the above technical solution, by setting the notches or grooves on the first surface, the electrolyte is not easy to enter the notches or grooves, and the electrolyte in the battery cell can all infiltrate the electrode assembly, which is not easy to cause electrolyte waste.

[0045] As an optional technical solution of an embodiment of the present application, the weak area includes a plurality of slot segments and a plurality of hole segments, and the slot segments and the hole segments are alternately arranged along the circumference of the second pressure relief area; along the first direction, the insulating member has a first surface and a second surface relative to each other, the slot segments are recessed from the first surface toward the second surface, and the hole segments pass through the first surface and the second surface.

[0046] In the above technical solution, the groove segments and hole segments have different incision depths. The hole segments penetrate the first and second surfaces and have a larger incision depth. The groove segments are recessed from the first surface toward the second surface and have a shallower incision depth. By arranging multiple groove segments and hole segments at intervals along the circumference of the second pressure relief area, the second pressure relief area is easily opened in the event of thermal runaway of the battery cell.

[0047] As an optional technical solution of the embodiment of the present application, the insulating member is provided with a groove, and the bottom wall of the groove forms the second pressure relief area.

[0048] In the above technical solution, a groove is provided on the insulating member to form a weak point. When the battery cell experiences thermal runaway, the bottom wall of the groove opens, allowing gas to pass through the insulating member and be discharged from the first pressure relief area.

[0049] As an optional technical solution of an embodiment of the present application, the melting point of the second pressure relief area is lower than the melting point of the insulating member.

[0050] In this technical solution, during normal battery cell operation, the second pressure relief region separates the electrode assembly from the first pressure relief region. Even if the battery cell is subjected to vibration, the electrolyte in the housing is unlikely to flush the first pressure relief region and affect its detonation pressure. In the event of thermal runaway, the high temperature of the gas melts the second pressure relief region, allowing the gas to pass through the insulating member and release pressure from the first pressure relief region, thus providing a high level of safety.

[0051] As an optional technical solution of the embodiment of the present application, the melting point of the second pressure relief area is M, which satisfies: 80°C≤M≤180°C.

[0052] In the above technical solution, a material with a melting point of 80-180°C is selected as the second pressure relief area. This can not only ensure that the second pressure relief area can be melted by the high-temperature gas in the event of thermal runaway of the battery cell, but also reduce the risk of the second pressure relief area being melted when the battery cell is operating normally. When M is less than 80°C, the second pressure relief area may be melted by the normal operating temperature of the battery cell, causing the electrolyte to flush the first pressure relief area, affecting the detonation pressure of the first pressure relief area. When M is greater than 180°C, the melting point of the second pressure relief area is higher and it is not easy to melt under the action of the high-temperature gas, resulting in the battery cell being unable to release pressure or the pressure release being delayed.

[0053] As an optional technical solution of an embodiment of the present application, the insulating member is provided with a plurality of second pressure relief areas, at least part of which is used to open when the battery cell thermally runs away. Along a first direction, the insulating member is arranged opposite to the wall portion, and the projection of the first pressure relief area on the insulating member along the first direction covers at least part of the second pressure relief area.

[0054] In this technical solution, the insulating member is provided with multiple second pressure relief areas. In the event of thermal runaway of a battery cell, at least some of these second pressure relief areas open, allowing gas to pass through the insulating member and release pressure from the first pressure relief areas, thus providing a higher level of safety. The provision of multiple second pressure relief areas reinforces the space between adjacent second pressure relief areas, thereby ensuring the strength of the insulating member and providing a certain degree of support for the electrode assembly.

[0055] As an optional technical solution of an embodiment of the present application, the first part of the second pressure relief area is located within the projection range of the first pressure relief area along the first direction on the insulating part, and the second part of the second pressure relief area is located outside the projection range of the first pressure relief area along the first direction on the insulating part.

[0056] In the above technical solution, the first portion of the second pressure relief area is positioned directly opposite the first pressure relief area. In the event of thermal runaway of a battery cell, gas can more quickly pass through the insulation and release pressure from the first pressure relief area. The second portion of the second pressure relief area is offset from the first pressure relief area. The second portion of the second pressure relief area opens in the event of thermal runaway of a battery cell, increasing the area for gas to pass through the insulation.

[0057] As an optional technical solution of an embodiment of the present application, along the first direction, the insulating member has a first surface facing the wall portion, and an exhaust groove is provided on the first surface. The exhaust groove is used to guide the gas from the second pressure relief area of ​​the second part to the first pressure relief area when the battery cell thermally runs away.

[0058] In the above technical solution, the gap between the insulating member and the wall is small, making it difficult for gas exhausted from the second pressure relief area of ​​the second portion to flow to the first pressure relief area. By providing the exhaust groove on the first surface, a larger gap is formed between the bottom wall of the exhaust groove and the wall. This allows gas exhausted from the second pressure relief area of ​​the second portion to flow quickly to the first pressure relief area through the exhaust groove, thereby increasing the pressure relief speed.

[0059] As an optional technical solution of the embodiment of the present application, the exhaust groove extends to the second part of the second pressure relief area, and the projection of the first pressure relief area on the insulating member along the first direction covers a part of the exhaust groove.

[0060] In the above technical solution, when the battery cell thermally runs away, the second pressure relief area of ​​the second part opens, and the gas enters the exhaust groove from the second pressure relief area of ​​the second part. Under the guidance of the exhaust groove, the gas flows to the first pressure relief area, which facilitates to increase the pressure relief speed and achieve smooth pressure relief.

[0061] As an optional technical solution of the embodiment of the present application, the insulating member is provided with a plurality of weak areas, each of the weak areas corresponds to the second pressure relief area one by one, and the weak areas are provided along the edge of the second pressure relief area.

[0062] In the above technical solution, multiple weak areas are provided on the insulating member, facilitating the opening of the second pressure relief area from the weak areas in the event of thermal runaway of the battery cell. Because the weak areas are provided along the edges of the second pressure relief area, the second pressure relief area will open along the edges in the event of thermal runaway of the battery cell, providing a larger opening for gas to pass through.

[0063] As an optional technical solution of the embodiment of the present application, a through hole is opened on the insulating member, and the area defined by the peripheral wall of the through hole is the second pressure relief area.

[0064] In the above technical solution, the second pressure relief area is an area surrounded by the through holes opened on the insulating member. When the battery cell is in normal use or in thermal runaway, the gas can pass through the insulating member to reach the first pressure relief area.

[0065] As an optional technical solution of the embodiment of the present application, the insulating member is a flat plate structure.

[0066] In the above technical solution, the insulating member is configured as a flat plate structure, which, on the one hand, occupies a smaller volume within the battery cell, and on the other hand, can provide a better support effect for the electrode assembly and is not prone to damage to the electrode assembly.

[0067] As an optional technical solution of the embodiment of the present application, the thickness of the insulating member is N, satisfying 0.5mm≤N≤10mm.

[0068] In the above technical solution, limiting the thickness of the insulating member to 0.5-10mm can ensure the insulating effect and supporting capacity of the insulating member while also reducing the space occupied by the insulating member inside the battery cell. When N < 0.5mm, the thickness of the insulating member is small, the supporting capacity is poor, and the insulating effect is poor (relatively easy to be broken down). When N > 10mm, the insulating member is large, which is not conducive to improving the energy density of the battery cell.

[0069] As an optional technical solution of an embodiment of the present application, the battery cell includes an electrode terminal, the shell has a first wall, the electrode terminal is arranged on the first wall, the electrode terminal is electrically connected to the electrode assembly, and the first wall and the wall portion are different walls.

[0070] In the above technical solution, the electrode terminals can output power from the battery cells or input power to the battery cells. The electrode terminals and the first pressure relief area are arranged on different walls. In this way, there is no need to provide a through hole in the insulating member to allow the electrode terminals to be electrically connected to the electrode assembly.

[0071] In a second aspect, an embodiment of the present application provides a battery, comprising a housing and the above-mentioned battery cell.

[0072] In a third aspect, an embodiment of the present application provides an electric device, which includes the above-mentioned battery, and the battery is used to provide electrical energy to the electric device. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] 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.

[0074] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0075] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0076] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0077] FIG4 is a front view schematic diagram of an insulating member provided in some embodiments of the present application;

[0078] FIG5 is a cross-sectional view taken along line BB in FIG4 ;

[0079] FIG6 is a front view schematic diagram of an insulating member provided in some other embodiments of the present application;

[0080] FIG7 is a cross-sectional view taken along the CC line in FIG6 ;

[0081] FIG8 is a front view schematic diagram of an insulating member provided in some other embodiments of the present application;

[0082] FIG9 is a cross-sectional view of the DD position in FIG8;

[0083] FIG10 is a front view schematic diagram of an insulating member provided in some further embodiments of the present application;

[0084] FIG11 is a cross-sectional view of the EE position in FIG10;

[0085] FIG12 is a front view schematic diagram of an insulating member provided in some other embodiments of the present application;

[0086] FIG13 is a cross-sectional view of the FF position in FIG12;

[0087] FIG14 is a front view schematic diagram of an insulating member provided in some other embodiments of the present application;

[0088] FIG15 is a front view schematic diagram of an insulating member provided in yet other embodiments of the present application;

[0089] FIG16 is a cross-sectional view of the GG position in FIG15;

[0090] FIG17 is a front view schematic diagram of an insulating member provided in yet other embodiments of the present application;

[0091] FIG18 is a cross-sectional view taken along line HH in FIG17 ;

[0092] FIG19 is a front view schematic diagram of an insulating member provided in some other embodiments of the present application;

[0093] FIG20 is a cross-sectional view of position II in FIG19.

[0094] Icons: 10-housing; 11-first part; 12-second part; 20-battery cell; 21-electrode assembly; 22-housing; 221-end cover; 222-housing body; 2221-wall; 2222-first pressure relief area; 23-insulating member; 231-second pressure relief area; 232-weak area; 2321-weak section; 2322-groove section; 2323-hole section; 233-first surface; 234-second surface; 235-groove; 236-filler; 237-exhaust groove; 238-through hole; 100-battery; 200-controller; 300-motor; 1000-vehicle. DETAILED DESCRIPTION

[0095] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0096] 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 for the purpose of describing specific embodiments only 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0101] The term "plurality" used in this application refers to two or more (including two).

[0102] 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.

[0103] The battery cells can be 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, etc., which are not limited in the embodiments of the present application.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] As an example, the positive electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, 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.).

[0108] 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 may also be used. These positive electrode active materials may be used alone or in combination of two or more. 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.

[0109] In some embodiments, a positive electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam, among others. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not be provided with a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled and / or deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0110] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0111] As an example, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, 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 (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.).

[0112] 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.

[0113] 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 provided on either or both of the two facing surfaces of the negative electrode current collector.

[0114] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. 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, and lithium titanate.

[0115] In some embodiments, the negative electrode may be a metal foam. The metal foam may be nickel foam, copper foam, aluminum foam, alloy foam, or carbon foam. When the metal foam is used as the negative electrode sheet, the surface of the metal foam may or may not be provided with a negative electrode active material.

[0116] 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.

[0117] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0118] 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.

[0119] As an example, the main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics.

[0120] 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.

[0121] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and the electrolyte can be selected based on needs. The electrolyte can be liquid, gel, or solid.

[0122] 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.

[0123] In some embodiments, the electrode assembly is a laminate structure.

[0124] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0125] 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.

[0126] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of stacked folded segments.

[0127] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0128] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0129] In some embodiments, the shape of the electrode assembly can be cylindrical, flat, or polygonal.

[0130] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0131] 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), or a composite metal housing (e.g., a copper-aluminum composite housing).

[0132] 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 this application.

[0133] In some embodiments, the housing includes end caps and a housing body. The housing body has an opening, and the end caps seal the opening to form a sealed space for accommodating the electrode assembly, electrolyte, and other materials. The housing body may have one or more openings. One or more end caps may also be provided.

[0134] In some embodiments, the housing is provided with at least one electrode terminal, which is electrically connected to the tab. The electrode terminal may be directly connected to the tab or indirectly connected to the tab via an adapter component. The electrode terminal may be provided on the end cap or on the housing body.

[0135] In some embodiments, the housing is provided with a pressure relief mechanism for releasing the internal pressure of the battery cell.

[0136] As an example, the pressure relief mechanism may be integrally formed with the housing.

[0137] As an example, the pressure relief mechanism may also be provided separately from and connected to the housing.

[0138] The battery mentioned in the embodiments of the present application may include one or more battery cells to provide a single physical module with higher voltage and capacity. When there are multiple battery cells, the multiple battery cells are connected in series, in parallel or in hybrid through a busbar.

[0139] 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.

[0140] 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.

[0141] The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as battery life, energy density, discharge capacity, and charge / discharge rate. Furthermore, battery safety must be considered. However, current battery safety is relatively poor.

[0142] To ensure the safety of battery cells, a pressure relief mechanism can be installed on the battery cells. When the battery cells experience thermal runaway, the pressure relief mechanism opens to release the pressure inside the battery cells, thereby reducing the risk of explosion or fire.

[0143] The inventors have noticed that a short circuit is likely to occur between the wall portion where the pressure relief mechanism is provided and the electrode assembly.

[0144] The inventors further discovered that if an insulating member is directly provided between the wall and the electrode assembly, although the short circuit problem between the wall and the electrode assembly can be solved, the insulating member will block the gas from flowing to the wall, making it impossible to release pressure when the battery cell experiences thermal runaway.

[0145] In view of this, an embodiment of the present application provides a battery cell, which includes an electrode assembly, a shell and an insulating member. The shell is used to accommodate the electrode assembly, and the shell has a wall portion. The wall portion is provided with a first pressure relief area, and the first pressure relief area is used to open when the battery cell thermally runs away. The insulating member is at least partially provided between the electrode assembly and the wall portion to insulate and isolate the electrode assembly and the wall portion. Among them, a second pressure relief area is provided at a position of the insulating member corresponding to the first pressure relief area, and the second pressure relief area is used to allow gas to pass through the insulating member to reach the first pressure relief area when the battery cell thermally runs away.

[0146] An insulating member is installed between the battery cell's electrode assembly and the wall portion where the first pressure relief area is located, insulating the wall and the electrode assembly, enhancing the safety of the battery cell. The insulating member also features a second pressure relief area corresponding to the first pressure relief area. In the event of thermal runaway of the battery cell, the second pressure relief area allows gas to pass through the insulating member and release pressure from the first pressure relief area, providing a higher level of safety.

[0147] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0148] Electrically powered devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Electric tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0149] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle 1000 as an example.

[0150] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The 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 serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0151] 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.

[0152] Please refer to Figure 2, which is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a storage space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cell 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. Alternatively, the first portion 11 and the second portion 12 can each be a hollow structure with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a rectangular parallelepiped, etc.

[0153] 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.

[0154] Each battery cell 20 may be a secondary battery cell or a primary battery cell; it may also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0155] Please refer to Figure 3, which is an exploded view of a battery cell 20 provided in some embodiments of the present application. A battery cell 20 is the smallest unit that makes up a battery 100. As shown in Figure 3, a battery cell 20 includes an electrode assembly 21, a housing 22, and other functional components. The housing 22 includes an end cap 221 and a housing body 222, with the end cap 221 connected to the housing body 222.

[0156] The end cap 221 refers to a component that covers the opening of the shell body 222 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 221 can be adapted to the shape of the shell body 222 to match the shell body 222. Optionally, the end cap 221 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 221 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals can be provided on the end cap 221. The electrode terminal can be used to electrically connect to the electrode assembly 21 for outputting or inputting electrical energy of the battery cell 20. The material of the end cap 221 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0157] The shell body 222 is a component that cooperates with the end cap 221 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 21, electrolyte, and other components. The shell body 222 and the end cap 221 can be independent components. An opening can be provided in the shell body 222, and the end cap 221 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 221 and the shell body 222 can be integrated. Specifically, the end cap 221 and the shell body 222 can form a common connection surface before other components are inserted into the shell. When the interior of the shell body 222 needs to be encapsulated, the end cap 221 is placed over the shell body 222. The shell body 222 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell body 222 can be determined based on the specific shape and size of the electrode assembly 21. The shell body 222 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0158] Please refer to Figures 3, 4, and 5. Figure 4 is a schematic front view of an insulating member 23 provided in some embodiments of the present application. Figure 5 is a cross-sectional view taken at position BB in Figure 4. Embodiments of the present application provide a battery cell 20 comprising an electrode assembly 21, a housing 22, and an insulating member 23. The housing 22 is configured to house the electrode assembly 21. The housing 22 has a wall 2221, which is provided with a first pressure relief area 2222. The first pressure relief area 2222 is configured to open in the event of thermal runaway of the battery cell 20. The insulating member 23 is at least partially disposed between the electrode assembly 21 and the wall 2221 to insulate and isolate the electrode assembly 21 from the wall 2221. A second pressure relief area 231 is provided on the insulating member 23 at a position corresponding to the first pressure relief area 2222. The second pressure relief area 231 is configured to allow gas to pass through the insulating member 23 to the first pressure relief area 2222 in the event of thermal runaway of the battery cell 20.

[0159] It should be noted that the dotted line in FIG. 4 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0160] The first pressure relief area 2222 can be opened to release the pressure inside the battery cell 20 when the battery cell 20 thermally runs away, thereby reducing the risk of explosion or fire of the battery cell 20. Thermal runaway of the battery cell 20 means that the internal pressure or temperature of the battery cell 20 reaches the detonation pressure.

[0161] The phrase “the wall portion 2221 is provided with the first pressure relief area 2222” includes both the first pressure relief area 2222 being directly provided on the wall portion 2221 and the first pressure relief area 2222 being indirectly provided on the wall portion 2221. For example, if an intermediate component is provided on the wall portion 2221 and the first pressure relief area 2222 is located on the intermediate component, then the first pressure relief area 2222 is indirectly provided on the wall portion 2221.

[0162] The housing 22 has multiple walls, such as a bottom wall, side walls, and a top wall. The wall portion 2221 refers to the wall on which the first pressure relief area 2222 is provided. For example, if the first pressure relief area 2222 is provided on the bottom wall, the wall portion 2221 refers to the bottom wall of the housing 22. For another example, if the first pressure relief area 2222 is provided on the top wall, the wall portion 2221 refers to the top wall of the housing 22. For another example, if the first pressure relief area 2222 is provided on the side wall, the wall portion 2221 refers to the side wall of the housing 22. For another example, if the first pressure relief area 2222 is provided on the end cover 221, the wall portion 2221 may also refer to the end cover 221.

[0163] The insulating member 23 is a component made of an insulating material with insulating properties. Insulating materials include, but are not limited to, plastic or rubber. The insulating member 23 is used to insulate the electrode assembly 21 from the wall portion 2221, preventing electrical connection between the electrode assembly 21 and the wall portion 2221, which could cause a short circuit in the battery cells 20. The insulating member 23 may be located entirely or partially between the electrode assembly 21 and the wall portion 2221.

[0164] The second pressure relief region 231 can allow the gas in the battery cell 20 to be discharged from the first pressure relief region 2222 through the insulating member 23 when the battery cell 20 thermally runs away, thereby releasing the pressure.

[0165] An insulating member 23 is installed between the electrode assembly 21 of the battery cell 20 and the wall portion 2221 where the first pressure relief area 2222 is located. This insulates the wall portion 2221 from the electrode assembly 21, enhancing the safety of the battery cell 20. The insulating member 23 includes a second pressure relief area 231 corresponding to the first pressure relief area 2222. In the event of thermal runaway of the battery cell 20, the second pressure relief area 231 allows gas to pass through the insulating member 23 and release pressure from the first pressure relief area 2222, providing a higher level of safety.

[0166] In some embodiments, the second pressure relief region 231 is configured to open when the battery cell 20 experiences thermal runaway.

[0167] During normal use of the battery cell 20, the second pressure relief region 231 separates the electrode assembly 21 from the first pressure relief region 2222. Even if the battery cell 20 is subjected to vibration, the electrolyte within the housing 22 is unlikely to flush the first pressure relief region 2222 and affect the detonation pressure of the first pressure relief region 2222. In some embodiments, the wall portion 2221 is provided with a pressure relief groove, and the first pressure relief region 2222 is designed to open along the pressure relief groove in the event of thermal runaway of the battery cell 20. Along the first direction, the insulating member 23 is disposed opposite the wall portion 2221, with the projection of the insulating member 23 covering the pressure relief groove.

[0168] The first direction is the direction in which the wall portion 2221 of the housing 22, where the first pressure relief area 2222 is provided, points along an axis perpendicular to the wall portion 2221 itself toward the electrode assembly 21. Referring to FIG4 , the first direction may be direction A as shown in the figure.

[0169] The pressure relief groove can be provided on the surface of the wall portion 2221 facing the insulating member 23, or on the surface of the wall portion 2221 facing away from the insulating member 23. For example, taking the wall portion 2221 as a rectangular flat plate structure, the wall portion 2221 has a third surface and a fourth surface facing each other in the first direction, with the third surface facing the insulating member 23 and the fourth surface facing away from the insulating member 23. The pressure relief groove can be provided on the third surface of the wall portion 2221, or on the fourth surface of the wall portion 2221.

[0170] The pressure relief groove is a relatively weak point on the wall portion 2221. In the event of thermal runaway of the battery cell 20, the first pressure relief area 2222 will open along the pressure relief groove. By having the projection of the insulating member 23 along the first direction cover the pressure relief groove, the electrolyte is less likely to flush into the pressure relief groove, thereby less likely to affect the detonation pressure of the first pressure relief area 2222.

[0171] In some embodiments, along the first direction, the projection of the second pressure relief area 231 covers the projection of the first pressure relief area 2222 .

[0172] “The projection of the second pressure relief area 231 covers the projection of the first pressure relief area 2222” can also be understood as the position of the second pressure relief area 231 corresponds to the position of the first pressure relief area 2222, and the area of ​​the second pressure relief area 231 is greater than or equal to the area of ​​the first pressure relief area 2222.

[0173] When the electrolyte flushes the first pressure relief area 2222, the external force exerted on the first pressure relief area 2222 may cause the first pressure relief area 2222 to rupture from the pressure relief groove and separate from the wall portion 2221. By making the projection of the second pressure relief area 231 along the first direction cover the projection of the first pressure relief area 2222, the electrolyte is less likely to flush the first pressure relief area 2222, thereby less likely to affect the detonation pressure of the first pressure relief area 2222.

[0174] In some embodiments, along the first direction, the projection of the second pressure relief area 231 covers the pressure relief groove.

[0175] Along the first direction, the projection of the second pressure relief area 231 may cover only the pressure relief groove, or may cover both the pressure relief groove and the first pressure relief area 2222. In the embodiment where the second pressure relief area 231 covers both the pressure relief groove and the first pressure relief area 2222, the area of ​​the second pressure relief area 231 is larger than that of the first pressure relief area 2222.

[0176] The projection of the second pressure relief area 231 along the first direction covers the pressure relief groove. During normal use of the battery cell 20, the second pressure relief area 231 can block the electrolyte, reducing the risk of electrolyte scouring the pressure relief groove. In the event of thermal runaway of the battery cell 20, the second pressure relief area 231 opens, allowing gas to reach the pressure relief groove more quickly, causing the bottom wall of the pressure relief groove to rupture in time, thereby achieving rapid pressure relief and improving the safety of the battery cell 20.

[0177] 4 and 5 , in some embodiments, the insulating member 23 is provided with a weak area 232 , and the weak area 232 is provided along the edge of the second pressure relief area 231 .

[0178] The weak area 232 may be formed by thinning the insulating member 23 by notching or grooves. The strength of the weak area 232 is relatively low, so that the weak area 232 can be cracked under the action of gas when the battery cell 20 experiences thermal runaway.

[0179] By providing the weak area 232 on the insulating member 23, the second pressure relief area 231 can be opened from the weak area 232 when the battery cell 20 experiences thermal runaway. Because the weak area 232 is provided along the edge of the second pressure relief area 231, when the battery cell 20 experiences thermal runaway, the second pressure relief area 231 will open along the edge, providing a larger opening for gas to pass through.

[0180] In some embodiments, the weak area 232 is disposed around the outer side of the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0181] The phrase "the weak area 232 is disposed around the outside of the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction" can also be understood as the weak area 232 being disposed outside the first pressure relief area 2222. In other words, along the first direction, the first pressure relief area 2222 is located within the range defined by the projection of the weak area 232 on the wall portion 2221.

[0182] Because the weak area 232 is located along the edge of the second pressure relief area 231 and surrounds the outer side of the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction, the second pressure relief area 231 is larger than the first pressure relief area 2222. In other words, along the first direction, the projection of the second pressure relief area 231 on the wall portion 2221 overlaps the first pressure relief area 2222. This allows for smoother pressure relief when the battery cell 20 experiences thermal runaway.

[0183] In other embodiments, along the first direction, the projection of the weak area 232 on the wall portion 2221 is located within the first pressure relief area 2222. In this case, the area of ​​the opening formed by the second pressure relief area 231 is smaller than or equal to the area of ​​the first pressure relief area 2222.

[0184] In some embodiments, the pressure relief groove is formed in the wall portion 2221 and is disposed along the edge of the first pressure relief region 2222. The weak area 232 is disposed around the outer side of the projection of the pressure relief groove on the insulating member 23 along the first direction.

[0185] The pressure relief groove can be a groove body that is recessed from the surface of the wall portion 2221 along a first direction, and the first pressure relief area 2222 is the portion defined by the inner side surface of the groove body. Taking the inner side surface of the pressure relief groove as an example, the first pressure relief area 2222 is the rectangular portion of the wall portion 2221 defined by the inner side surface of the pressure relief groove. The pressure relief groove can also be a linear groove extending along a curved trajectory. For example, if the curved trajectory is a U-shaped trajectory, the first pressure relief area 2222 is the U-shaped portion of the wall portion 2221 defined by the curved trajectory. For another example, if the curved trajectory is a rectangular trajectory, the first pressure relief area 2222 is the rectangular portion of the wall portion 2221 defined by the curved trajectory. If the pressure relief groove is a linear groove extending along the curved trajectory, when the internal pressure of the battery cell 20 reaches the detonation pressure, the first pressure relief area 2222 can open with the pressure relief groove as the boundary to release the pressure inside the battery cell 20.

[0186] The phrase "the weak area 232 is disposed around the outside of the projection of the pressure relief groove on the insulating member 23 along the first direction" can also be understood as the weak area 232 being disposed around the outside of the pressure relief groove. In other words, along the first direction, the pressure relief groove is located within the range defined by the projection of the weak area 232 on the wall portion 2221.

[0187] By providing a pressure relief groove on the wall portion 2221, a weak point is formed, which facilitates the opening of the first pressure relief area 2222 from the weak point when the battery cell 20 experiences thermal runaway. Because the pressure relief groove is provided along the edge of the first pressure relief area 2222, when the battery cell 20 experiences thermal runaway, the first pressure relief area 2222 will open along the edge, providing a larger opening for gas to pass through.

[0188] In other embodiments, the battery cell 20 includes a pressure relief member, a pressure relief hole is defined in the wall portion 2221, and the pressure relief member covers the pressure relief hole. A pressure relief groove is defined in the pressure relief member. The weak area 232 is disposed around the outer side of a projection of the pressure relief groove along the first direction onto the insulating member 23.

[0189] The pressure relief member can be a sheet-like structure, and the pressure relief member can be welded to the wall portion 2221 to cover the pressure relief hole. The pressure relief groove is provided on the pressure relief member.

[0190] The phrase "the weak area 232 is disposed around the outside of the projection of the pressure relief groove on the insulating member 23 along the first direction" can also be understood as the weak area 232 being disposed around the outside of the pressure relief groove. In other words, along the first direction, the pressure relief groove is located within the range defined by the projection of the weak area 232 on the wall portion 2221.

[0191] By providing a pressure relief groove on the pressure relief member, a weak position is formed, so that the first pressure relief area 2222 can be opened from the weak position when the battery cell 20 experiences thermal runaway.

[0192] Optionally, the pressure relief groove is provided along the edge of the first pressure relief area 2222, so that the first pressure relief area 2222 is open along the edge to provide a larger opening for gas to pass through.

[0193] In some embodiments, the weak area 232 is disposed around the outer side of the projection of the pressure relief hole on the insulating member 23 along the first direction.

[0194] The phrase "weakened area 232 surrounds and is disposed outside the projection of the pressure relief hole on the insulating member 23 along the first direction" can also be understood as meaning that the weakened area 232 surrounds and is disposed outside the pressure relief hole. In other words, along the first direction, the pressure relief hole is located within the range defined by the projection of the weakened area 232 on the wall portion 2221.

[0195] By surrounding the weak area 232 and circumferentially surrounding the projection of the pressure relief hole onto the insulating member 23 along the first direction, if the weak area 232 penetrates the insulating member 23, during normal use of the battery cell 20, the electrolyte will not flow directly to the pressure relief member after passing through the weak area 232. Instead, it will first collide with the wall portion 2221 and change its flow direction, reducing the impact force before flowing to the pressure relief member. This makes the pressure relief member less susceptible to electrolyte erosion. In addition, in the event of thermal runaway of the battery cell 20, the open area of ​​the second pressure relief region 231 is larger than the area of ​​the pressure relief hole, facilitating smooth pressure relief.

[0196] 4 and 5 , in some embodiments, the weak area 232 includes a plurality of weak segments 2321 , and the plurality of weak segments 2321 are arranged at intervals along the circumference of the second pressure relief area 231 .

[0197] The weak section 2321 is part of the weak area 232. Multiple weak sections 2321 together form the weak area 232. "Multiple weak sections 2321 are arranged at intervals along the circumference of the second pressure relief area 231" can also be said to be multiple weak sections 2321 are arranged at intervals along the circumference of the first pressure relief area 2222.

[0198] By providing multiple weak sections 2321, in the event of thermal runaway of the battery cell 20, the second pressure relief area 231 can be opened at the locations of the multiple weak sections 2321, allowing gas to pass through the insulating member 23 and release pressure from the first pressure relief area 2222. Because the multiple weak sections 2321 are spaced apart circumferentially along the second pressure relief area 231, the area between adjacent weak sections 2321 acts as a reinforcing rib, providing increased strength for the second pressure relief area 231. Even if the battery cell 20 is subjected to significant vibration, the second pressure relief area 231 will not accidentally open.

[0199] 4 and 5 , in some embodiments, the weak section 2321 is strip-shaped and has a width D1 that satisfies: D1 ≤ 2 mm.

[0200] The weak section 2321 extends along the circumference of the second pressure relief area 231. The extension direction of the weak section 2321 is also its length direction. D1 represents the width of the weak section 2321. The widths of the multiple weak sections 2321 can be the same or different, but are all less than or equal to 2 mm. In this embodiment, the widths of the multiple weak sections 2321 are the same. The width of the weak section 2321 can be: D1 = 2 mm, 1.8 mm, 1.5 mm, 1.2 mm, 1 mm, 0.8 mm, 0.5 mm, etc.

[0201] The width of the weak section 2321 is less than 2 mm, which effectively limits the width of the remaining portion between two adjacent weak sections 2321. The smaller the width of this portion, the easier it is for the second pressure relief area 231 to open in the event of thermal runaway of the battery cell 20. If D1 is greater than 2 mm, the width of the remaining portion between two adjacent weak sections 2321 is also greater than 2 mm. This larger width prevents the second pressure relief area 231 from opening in time in the event of thermal runaway of the battery cell 20, preventing timely pressure relief in the battery cell 20.

[0202] 4 and 5 , in some embodiments, along the circumference of the second pressure relief area 231 , the distance between two adjacent weak sections 2321 is D2 , satisfying: D2 ≤ 10 mm.

[0203] Along the circumference of the second pressure relief area 231, the multiple weak sections 2321 can be arranged at equal or unequal intervals, but the distance between two adjacent weak sections 2321 is less than or equal to 10 mm. In this embodiment, the multiple weak sections 2321 are arranged at equal intervals along the circumference of the second pressure relief area 231. The distance between two adjacent weak sections 2321 along the circumference of the second pressure relief area 231 can take the following values: D2 = 10 mm, 9.5 mm, 9 mm, 8.5 mm, 8 mm, 7.5 mm, 6 mm, 5 mm, 4 mm, 3 mm, etc.

[0204] When one of the two adjacent weak sections 2321 is an arc-shaped weak section 2321, the distance between the two adjacent weak sections 2321 along the circumference of the second pressure relief area 231 refers to the shortest straight-line distance between the end surface of the first weak section 2321 close to the second weak section 2321 and the end surface of the second weak section 2321 close to the first weak section 2321.

[0205] The distance between two adjacent weak sections 2321 is the length of the remaining portion between the two adjacent weak sections 2321. The smaller the length of this portion, the easier it is for the second pressure relief area 231 to open in the event of thermal runaway of the battery cell 20. If D2 is greater than 10 mm, the length of the remaining portion between the two adjacent weak sections 2321 is also greater than 10 mm. This length may prevent the second pressure relief area 231 from opening in a timely manner in the event of thermal runaway of the battery cell 20, preventing timely pressure relief in the battery cell 20.

[0206] 4 and 5 , in some embodiments, in a direction perpendicular to the first direction, a distance D3 between the weak area 232 and the first pressure relief area 2222 satisfies: D3 ≤ 3 mm.

[0207] The distance between the weak area 232 and the first pressure relief area 2222 can be different at different locations, or the distance between the weak area 232 and the first pressure relief area 2222 can be the same at different locations. However, in a direction perpendicular to the first direction, the distance between the weak area 232 and the first pressure relief area 2222 is less than or equal to 3 mm. In a direction perpendicular to the first direction, the distance between the weak area 232 and the first pressure relief area 2222 can take the following values: D3 = 3 mm, 2.8 mm, 2.5 mm, 2.2 mm, 2 mm, 1.8 mm, 1.5 mm, 1 mm, etc.

[0208] By limiting the distance between the weak area 232 and the first pressure relief area 2222 in a direction perpendicular to the first direction, the area relationship between the second pressure relief area 231 and the first pressure relief area 2222 is effectively limited. The area of ​​the second pressure relief area 231 is larger than that of the first pressure relief area 2222, but the area of ​​the second pressure relief area 231 cannot be too large. Otherwise, when the second pressure relief area 231 is opened, the second pressure relief area 231 separates from the insulating member 23, and the separated portion may fall into the first pressure relief area 2222, thereby blocking the first pressure relief area 2222 and affecting the pressure relief of the first pressure relief area 2222.

[0209] Please refer to Figures 8 and 9. Figure 8 is a front view of an insulating member 23 provided in some other embodiments of the present application. Figure 9 is a cross-sectional view taken at position DD in Figure 8. In some other embodiments, the weak area 232 is a closed structure extending along a closed track.

[0210] It should be noted that the dotted line in FIG8 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0211] A closed track is a track connected at both ends, such as a rectangular track, an elliptical track, etc. The shape of the weak area 232 is the same as that of the closed track.

[0212] The weak area 232 is provided along the entire circumference of the edge of the second pressure relief area 231 , so that the second pressure relief area 231 can be easily opened when the battery cell 20 experiences thermal runaway.

[0213] In some embodiments, notches, grooves, or through holes are provided on the insulating member 23 to form a weak area 232 .

[0214] The notches or grooves can be provided on the surface of the insulating member 23 facing the wall portion 2221, or on the surface of the insulating member 23 facing away from the wall portion 2221. For example, taking the insulating member 23 as a rectangular flat plate structure, the insulating member 23 has a first surface 233 and a second surface 234 that are opposite to each other in a first direction, with the first surface 233 facing the wall portion 2221 and the second surface 234 facing away from the wall portion 2221. The notches or grooves can be provided on the first surface 233 or the second surface 234 of the insulating member 23.

[0215] The notch can be a groove recessed from the surface of the insulating member 23 along a first direction, and the second pressure relief area 231 is the portion defined by the inner side of the groove. Optionally, a portion of the notch can penetrate the first surface 233 and the second surface 234 of the insulating member 23 to form a through hole. Taking the inner side of the notch as an example, the second pressure relief area 231 is the rectangular portion of the insulating member 23 defined by the inner side of the notch. The notch can also be a linear groove extending along a curved trajectory. For example, if the curved trajectory is a U-shaped trajectory, the second pressure relief area 231 is the U-shaped portion of the insulating member 23 defined by the curved trajectory. For another example, if the curved trajectory is a rectangular trajectory, the second pressure relief area 231 is the rectangular portion of the insulating member 23 defined by the curved trajectory. If the notch is a linear groove extending along the curved trajectory, when the internal pressure of the battery cell 20 reaches the detonation pressure, the second pressure relief area 231 can open with the notch as the boundary to release the pressure within the battery cell 20.

[0216] The shape of the notch, groove or through hole is not limited. For example, the shape of the notch, groove or through hole can be circular, arc-shaped or fan-shaped.

[0217] By providing notches and grooves in the insulating member 23, the insulating member 23 is thinned to form a weak point, which facilitates rupture when the battery cell 20 experiences thermal runaway. By providing through holes in the insulating member 23, multiple through holes can be provided, so that the gaps between two adjacent through holes are easily broken, facilitating rupture when the battery cell 20 experiences thermal runaway.

[0218] In some embodiments, the melting point of the weak region 232 is lower than the melting point of the insulating member 23 .

[0219] When the battery cell 20 is in thermal runaway, the temperature of the gas is high, and the high-temperature gas will melt the weak area 232 , thereby opening the second pressure relief area 231 and allowing the gas to pass through the insulating member 23 to reach the first pressure relief area 2222 .

[0220] In some other embodiments, the insulating member 23 is provided with notches, grooves or through holes, and the notches, grooves or through holes are filled with a filler 236 , wherein the melting point of the filler 236 is lower than the melting point of the insulating member 23 .

[0221] The filler 236 may fill a portion of the notch, groove 235 or through-hole, or may fill the entire notch, groove 235 or through-hole.

[0222] By providing notches and grooves on the insulating member 23, the insulating member 23 is thinned to form a weak point, which facilitates cracking when the battery cell 20 experiences thermal runaway. By providing through holes on the insulating member 23, multiple through holes can be provided, so that the gaps between two adjacent through holes are easily broken, which facilitates cracking when the battery cell 20 experiences thermal runaway. Filling the insulating member 23 with the notches, grooves, or through holes makes it difficult for the electrolyte to enter the notches or grooves, or for the electrolyte to flow through the through holes to the wall. In this way, the electrolyte in the battery cell 20 can all penetrate the electrode assembly, which reduces the waste of electrolyte.

[0223] In some embodiments, the insulating member 23 is provided with notches or grooves to form a weak area 232 . The insulating member 23 has a first surface 233 facing the wall portion 2221 , and the notches or grooves are provided on the first surface 233 .

[0224] The first surface 233 is the surface of the insulating member 23 facing the wall portion 2221 along the first direction, that is, the surface of the insulating member 23 facing away from the electrode assembly 21 along the first direction. The notch or groove is provided on the first surface 233 and is recessed toward the second surface 234.

[0225] By providing the notches or grooves on the first surface 233 , the electrolyte is not easily penetrated into the notches or grooves, and the electrolyte in the battery cell 20 can all infiltrate the electrode assembly 21 , thus preventing the electrolyte from being wasted.

[0226] Please refer to Figures 10 and 11. Figure 10 is a front view schematic diagram of the insulating member 23 provided in some further embodiments of the present application. Figure 11 is a cross-sectional view of the EE position in Figure 10. In some further embodiments, the weak area 232 includes a plurality of groove segments 2322 and a plurality of hole segments 2323. Along the circumference of the second pressure relief area 231, the groove segments 2322 and the hole segments 2323 are alternately arranged. Along the first direction, the insulating member 23 has a first surface 233 and a second surface 234 opposite to each other. The groove segment 2322 is recessed from the first surface 233 toward the second surface 234, and the hole segment 2323 passes through the first surface 233 and the second surface 234.

[0227] It should be noted that the dotted line in Figure 10 represents the projection range of the first pressure relief area 2222 along the first direction on the insulating member 23. The dotted line in Figure 11 is only for the convenience of illustrating the position of the slot section 2322 and does not represent the physical structure.

[0228] Along the circumference of the second pressure relief area 231, a hole section 2323 is located between every two adjacent slot sections 2322, and a slot section 2322 is located between every two adjacent hole sections 2323. The slot sections 2322 are slot-shaped structures that penetrate the first surface 233 of the insulating member 23 but do not penetrate the second surface 234 of the insulating member 23. The hole sections 2323 are hole-shaped structures that penetrate both the first surface 233 and the second surface 234 of the insulating member 23.

[0229] The groove sections 2322 and the hole sections 2323 have different depths. The hole section 2323 extends through the first surface 233 and the second surface 234 and has a greater depth. The groove section 2322 is recessed from the first surface 233 toward the second surface 234 and has a shallower depth. By arranging multiple groove sections 2322 and multiple hole sections 2323 at intervals along the circumference of the second pressure relief area 231, the second pressure relief area 231 is easily opened in the event of thermal runaway of the battery cell 20.

[0230] Please refer to Figures 6 and 7. Figure 6 is a front view of an insulating member 23 provided in some other embodiments of the present application. Figure 7 is a cross-sectional view taken along the CC axis of Figure 6. In some other embodiments, the insulating member 23 is provided with a groove 235, the bottom wall of which forms a second pressure relief area 231.

[0231] It should be noted that the dotted line in FIG. 6 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0232] During normal use of the battery cell 20, the bottom wall of the groove 235 separates the electrode assembly 21 from the first pressure relief area 2222. Even if the battery cell 20 is subjected to vibration, the electrolyte within the housing 22 is unlikely to flush into the first pressure relief area 2222 and affect the detonation pressure of the first pressure relief area 2222. In the event of thermal runaway of the battery cell 20, the bottom wall of the groove 235 opens, allowing gas to pass through the insulating member 23 and release pressure from the first pressure relief area 2222, thus providing a higher level of safety.

[0233] In some embodiments, the melting point of the second pressure relief area 231 is lower than the melting point of the insulating member 23 .

[0234] The insulating member 23 is provided with a through hole 238 , which passes through the first surface 233 and the second surface 234 of the insulating member 23 . The second pressure relief area 231 is provided in the through hole 238 and connected to the insulating member 23 .

[0235] During manufacturing, the insulating member 23 with the through hole 238 may be firstly injection molded by a mold, and then the second pressure relief area 231 may be injection molded in the through hole 238 .

[0236] During normal use of the battery cell 20, the second pressure relief area 231 separates the electrode assembly 21 from the first pressure relief area 2222. Even if the battery cell 20 is subjected to vibration, the electrolyte within the housing 22 is unlikely to flush out the first pressure relief area 2222 and affect the detonation pressure of the first pressure relief area 2222. In the event of thermal runaway of the battery cell 20, the high temperature of the gas will melt the second pressure relief area 231, allowing the gas to pass through the insulating member 23 and release pressure from the first pressure relief area 2222, thus providing a high level of safety.

[0237] In some embodiments, the melting point of the second pressure relief area 231 is M, which satisfies: 80°C≤M≤180°C.

[0238] The melting point of the second pressure relief area 231 can be: M = 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, 180°C, etc.

[0239] Selecting a material with a melting point of 80-180°C for the second pressure relief region 231 can ensure that the second pressure relief region 231 can be melted by the high-temperature gas in the event of thermal runaway of the battery cell 20, while also reducing the risk of the second pressure relief region 231 melting during normal operation of the battery cell 20. When M < 80°C, the second pressure relief region 231 may be melted by the normal operating temperature of the battery cell 20, causing the electrolyte to flush the first pressure relief region 2222, affecting the detonation pressure of the first pressure relief region 2222. When M > 180°C, the second pressure relief region 231 has a higher melting point and is not easily melted by the high-temperature gas, resulting in the battery cell 20 failing to release pressure or releasing pressure in a timely manner.

[0240] Please refer to Figures 12 and 13. Figure 12 is a front view schematic diagram of the insulating member 23 provided in some other embodiments of the present application. Figure 13 is a cross-sectional view of the FF position in Figure 12. In some other embodiments, the insulating member 23 is provided with a plurality of second pressure relief areas 231, and at least part of the second pressure relief areas 231 is used to open when the battery cell thermal runaway occurs. Along the first direction, the insulating member 23 is arranged opposite to the wall portion 2221. The projection of the first pressure relief area 2222 on the insulating member 23 along the first direction covers at least a portion of the second pressure relief area 231.

[0241] It should be noted that the dotted line in FIG. 12 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0242] The phrase "the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction covers at least a portion of the second pressure relief area 231" includes both the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction completely covering the plurality of second pressure relief areas 231 and the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction covering a portion of the second pressure relief areas 231. In short, all of the plurality of second pressure relief areas 231 may be disposed directly opposite the first pressure relief area 2222, or some of the second pressure relief areas 231 may be disposed offset from the first pressure relief area 2222 (not directly opposite the first pressure relief area 2222).

[0243] In the event of thermal runaway of a battery cell 20, at least a portion of the second pressure relief areas 231 opens, allowing gas to pass through the insulating member 23 and release pressure from the first pressure relief areas 2222, providing a higher level of safety. By providing multiple second pressure relief areas 231, the area between two adjacent second pressure relief areas 231 can be reinforced, thereby easily ensuring the strength of the insulating member 23 and providing a certain degree of support for the electrode assembly 21.

[0244] In some embodiments, the first portion of the second pressure relief area 231 is located within the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction, and the second portion of the second pressure relief area 231 is located outside the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0245] The first portion of the second pressure relief area 231 specifically refers to the second pressure relief area 231 located within the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction among the plurality of second pressure relief areas 231 .

[0246] The second portion of the second pressure relief area 231 specifically refers to the second pressure relief area 231 among the plurality of second pressure relief areas 231 that is located outside the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0247] In this embodiment, a portion of the second pressure relief area 231 may be located within the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction, and another portion may be located outside the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0248] The first portion of the second pressure relief area 231 is positioned directly opposite the first pressure relief area 2222. When a battery cell 20 experiences thermal runaway, gas can more quickly pass through the insulating member 23 and release pressure from the first pressure relief area 2222. The second portion of the second pressure relief area 231 is offset from the first pressure relief area 2222. The second portion of the second pressure relief area 231 opens when a battery cell 20 experiences thermal runaway, increasing the area through which gas can pass through the insulating member 23.

[0249] 12 and 13 , in some embodiments, along the first direction, the insulating member 23 has a first surface 233 facing the wall portion 2221 , and a venting groove 237 is provided on the first surface 233 . The venting groove 237 is used to guide gas from the second portion of the second pressure relief area 231 to the first pressure relief area 2222 when the battery cell 20 experiences thermal runaway.

[0250] The vent groove 237 is a groove structure provided in the insulating member 23. It is located on the side of the insulating member 23 that faces the wall portion 2221. Along a first direction, the vent groove 237 is recessed from the first surface 233 toward the second surface 234. In the event of thermal runaway of the battery cell 20, gas would flow from the second pressure relief area 231 through the insulating member 23. The vent groove 237 can direct the gas released from the second pressure relief area 231 to the first pressure relief area 2222.

[0251] The gap between the insulating member 23 and the wall portion 2221 is small, so the gas exhausted from the second portion of the second pressure relief area 231 is not easy to flow to the first pressure relief area 2222. By providing the exhaust groove 237 on the first surface 233, a larger gap is formed between the bottom wall of the exhaust groove 237 and the wall portion 2221. The gas exhausted from the second portion of the second pressure relief area 231 can flow quickly to the first pressure relief area 2222 through the exhaust groove 237, thereby increasing the pressure relief speed.

[0252] 12 and 13 , in some embodiments, the exhaust groove 237 extends to the second portion of the second pressure relief area 231 , and a projection of the first pressure relief area 2222 on the insulating member 23 along the first direction covers a portion of the exhaust groove 237 .

[0253] One end of the exhaust groove 237 is disposed in the second portion of the second pressure relief area 231 , and the other end of the exhaust groove 237 falls within the range of the projection of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0254] It should be noted that when the edge of the other end of the exhaust groove 237 overlaps with the edge of the projection of the first pressure relief area 2222 on the insulating part 23 along the first direction, it is also regarded as the projection of the first pressure relief area 2222 on the insulating part 23 along the first direction covering a part of the exhaust groove 237.

[0255] When the battery cell 20 thermally runs away, the second part of the second pressure relief area 231 opens, and the gas enters the exhaust groove 237 from the second part of the second pressure relief area 231. Under the guidance of the exhaust groove 237, the gas flows to the first pressure relief area 2222, thereby increasing the pressure relief speed and achieving smooth pressure relief.

[0256] 12 and 13 , in some embodiments, the insulating member 23 is provided with a plurality of weak areas 232 , each of the weak areas 232 corresponding to the second pressure relief areas 231 . The weak areas 232 are provided along the edge of the second pressure relief areas 231 .

[0257] By providing multiple weak areas 232 on the insulating member 23, the second pressure relief area 231 can be opened from the weak areas 232 when the battery cell 20 experiences thermal runaway. Because the weak areas 232 are provided along the edges of the second pressure relief area 231, when the battery cell 20 experiences thermal runaway, the second pressure relief area 231 will open along the edges, providing a larger opening for gas to pass through.

[0258] 12 and 13 , in some embodiments, the plurality of weak areas 232 are all closed structures extending along a closed trajectory.

[0259] Please refer to Figure 14, which is a front view of an insulating member 23 provided in some other embodiments of the present application. In some other embodiments, the weak area 232 includes a plurality of weak sections 2321, which are arranged at intervals along the circumference of the second pressure relief area 231.

[0260] In some embodiments, a through hole 238 is defined in the insulating member 23 , and an area defined by a peripheral wall of the through hole 238 serves as the second pressure relief area 231 .

[0261] The second pressure relief area 231 is an area surrounded by the through holes 238 opened on the insulating member 23 . When the battery cell 20 is in normal use or in thermal runaway, gas can pass through the insulating member 23 to reach the first pressure relief area 2222 .

[0262] Please refer to Figures 15 and 16. Figure 15 is a front view of an insulating member 23 provided in yet other embodiments of the present application. Figure 16 is a cross-sectional view taken at position GG in Figure 15. In yet other embodiments, the insulating member 23 is provided with a plurality of grooves 235, the bottom walls of the grooves 235 forming a second pressure relief area 231.

[0263] It should be noted that the dotted line in FIG. 15 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0264] Please refer to Figures 17 and 18. Figure 17 is a front view of an insulating member 23 provided in yet other embodiments of the present application. Figure 18 is a cross-sectional view taken along line HH in Figure 17. In yet other embodiments, a filler 236 is disposed within the groove 235, and the melting point of the filler 236 is lower than that of the insulating member 23.

[0265] It should be noted that the dotted line in FIG. 17 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0266] The filler 236 is filled in the groove 235 . The filler 236 may fill a portion of the groove 235 or the entire groove 235 .

[0267] When a battery cell 20 experiences thermal runaway, the high temperature of the gas can melt the filler 236. The bottom wall of the groove 235 opens under the action of the gas pressure within the battery cell 20, allowing the gas to escape through the insulating member 23 and out of the first pressure relief area 2222. The placement of the filler 236 within the groove 235 not only prevents electrolyte from accumulating within the groove 235, but also helps ensure a sufficient amount of electrolyte within the battery cell 20. It also provides effective support and positioning for the electrode assembly 21.

[0268] Please refer to Figures 19 and 20. Figure 19 is a schematic front view of an insulating member 23 provided in some other embodiments of the present application. Figure 20 is a cross-sectional view taken at position II in Figure 19. In some other embodiments, the insulating member 23 is provided with a plurality of through-holes 238, and the second pressure relief area 231 is disposed within the through-holes 238 and connected to the insulating member 23. The melting point of the second pressure relief area 231 is lower than that of the insulating member 23.

[0269] It should be noted that the dotted line in FIG. 19 represents the projection range of the first pressure relief area 2222 on the insulating member 23 along the first direction.

[0270] In some embodiments, the insulating member 23 is a flat plate structure.

[0271] The insulating member 23 is configured as a flat plate structure. On the one hand, it occupies a smaller volume in the battery cell 20. On the other hand, the flat plate structure can provide a better support effect for the electrode assembly 21 and is not prone to damage to the electrode assembly 21.

[0272] In some embodiments, the thickness of the insulating member 23 is N, satisfying 0.5 mm ≤ N ≤ 10 mm.

[0273] N represents the thickness of the insulating member 23 , which can also be understood as the distance between the first surface 233 and the second surface 234 along the first direction.

[0274] The thickness of the insulating member 23 can be: N = 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc. Limiting the thickness of the insulating member 23 to 0.5-10mm can not only ensure the insulation effect and support capacity of the insulating member 23, but also make the insulating member 23 occupy less space inside the battery cell 20. When N < 0.5mm, the thickness of the insulating member 23 is small, the support capacity is poor, and the insulation effect is poor (relatively easy to be broken down). When N > 10mm, the insulating member 23 is large, which is not conducive to improving the energy density of the battery cell 20.

[0275] In some embodiments, the battery cell 20 includes an electrode terminal, and the housing 22 has a first wall on which the electrode terminal is disposed. The electrode terminal is electrically connected to the electrode assembly 21 , and the first wall and the wall portion 2221 are different walls.

[0276] The housing 22 has multiple walls, such as a bottom wall, side walls, and a top wall. The first wall refers to the wall where the electrode terminals are located. For example, if the electrode terminals are located on the bottom wall, the first wall refers to the bottom wall of the housing 22. For another example, if the electrode terminals are located on the top wall, the first wall refers to the top wall of the housing 22. For another example, if the electrode terminals are located on the side walls, the first wall refers to the side walls of the housing 22. For another example, if the electrode terminals are located on the end cap 221, the first wall may also refer to the end cap 221.

[0277] It should be noted that the first wall and the wall portion 2221 are different walls of the outer shell 22 .

[0278] The electrode terminals can output power from the battery cells 20 or input power to the battery cells 20. The electrode terminals and the first pressure relief area 2222 are arranged on different walls, so that the insulating member 23 does not need to have a through hole allowing the electrode terminals to be electrically connected to the electrode assembly 21.

[0279] An embodiment of the present application provides a battery 100 , which includes a housing 10 and the aforementioned battery cells 20 , wherein the battery cells 20 are housed in the housing 10 .

[0280] An embodiment of the present application provides an electric device, which includes the above-mentioned battery 100, and the battery 100 is used to provide electric energy to the electric device.

[0281] According to some embodiments of the present application, please refer to FIG. 4 and FIG. 5 .

[0282] An embodiment of the present application provides a battery cell 20, which includes an electrode assembly 21, a shell 22 and an insulating member 23. The shell 22 is used to accommodate the electrode assembly 21. The shell 22 has a wall portion 2221 arranged opposite to the electrode assembly 21 along a first direction, and the wall portion 2221 is provided with a first pressure relief area 2222. Along the first direction, the insulating member 23 is at least partially arranged between the electrode assembly 21 and the wall portion 2221 to insulate and isolate the electrode assembly 21 and the wall portion 2221. Among them, the insulating member 23 is provided with a second pressure relief area 231 at a position corresponding to the first pressure relief area 2222, and the first pressure relief area 2222 and the second pressure relief area 231 are used to open when the battery cell 20 thermally runs away.

[0283] The insulating member 23 is provided with a weakened area 232, which is disposed around the outside of the first pressure relief area 2222. The weakened area 232 includes a plurality of weakened segments 2321, which are arranged at intervals along the circumference of the second pressure relief area 231. The weakened segments 2321 extend through two opposing surfaces of the insulating member 23 along the first direction.

[0284] An insulating member 23 is disposed between the electrode assembly 21 of the battery cell 20 and the wall portion 2221 where the first pressure relief area 2222 is located. The insulating member 23 has a second pressure relief area 231 corresponding to the position of the first pressure relief area 2222. During normal use of the battery cell 20, the second pressure relief area 231 separates the electrode assembly 21 from the first pressure relief area 2222. Even if the battery cell 20 is subjected to vibration, the electrolyte within the outer casing 22 is unlikely to flush the first pressure relief area 2222 and affect the detonation pressure of the first pressure relief area 2222. In the event of thermal runaway of the battery cell 20, the second pressure relief area 231 allows gas to pass through the insulating member 23 and release pressure from the first pressure relief area 2222, providing a higher level of safety.

[0285] By providing a weak area 232 on the insulating member 23, the second pressure relief area 231 can be opened from the weak area 232 in the event of thermal runaway of the battery cell 20. Because the weak area 232 is arranged along the edge of the second pressure relief area 231 and surrounds the outside of the first pressure relief area 2222, the second pressure relief area 231 is larger than the first pressure relief area 2222. In other words, along the first direction, the projection of the second pressure relief area 231 on the wall 2221 overlaps the first pressure relief area 2222. Thus, in the event of thermal runaway of the battery cell 20, the area of ​​the opening formed by the opening of the second pressure relief area 231 is larger than that of the first pressure relief area 2222, facilitating smooth pressure relief. By providing multiple weak sections 2321, in the event of thermal runaway of the battery cell 20, the second pressure relief area 231 can be opened from the locations of the multiple weak sections 2321, allowing gas to release pressure from the first pressure relief area 2222 through the insulating member 23. Because multiple weak sections 2321 are arranged at intervals along the circumference of the second pressure relief area 231, the second pressure relief area 231 has high strength. Even if the battery cell 20 is subjected to large vibrations, the second pressure relief area 231 will not accidentally open. By having the weak sections 2321 penetrate both surfaces of the insulating member 23 along the first direction, the second pressure relief area 231 is more easily opened when the battery cell 20 experiences thermal runaway. In addition, although the weak sections 2321 penetrate both surfaces of the insulating member 23 along the first direction, because the weak areas 232 are arranged around the outside of the first pressure relief area 2222, the electrolyte passing through the insulating member 23 will not directly flush into the first pressure relief area 2222. Instead, it may flow to the first pressure relief area 2222 after passing through the insulating member 23 and changing direction. In this way, the impact force of the electrolyte is not strong, and it is not easy to affect the detonation pressure of the first pressure relief area 2222.

[0286] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, wherein: include: electrode assembly; a housing for accommodating the electrode assembly, the housing having a wall portion, the wall portion being provided with a first pressure relief area, the first pressure relief area being configured to open when the battery cell experiences thermal runaway; an insulating member, at least partially disposed between the electrode assembly and the wall portion to insulate and isolate the electrode assembly from the wall portion; A second pressure relief area is provided on the insulating member at a position corresponding to the first pressure relief area. The second pressure relief area is used to allow gas to pass through the insulating member and reach the first pressure relief area when the battery cell experiences thermal runaway.

2. The battery cell according to claim 1, wherein: The second pressure relief area is configured to open when the battery cell experiences thermal runaway.

3. The battery cell according to claim 2, wherein: The wall portion is provided with a pressure relief groove, and the first pressure relief area is used to open along the pressure relief groove when the battery cell thermally runs away; Along the first direction, the insulating member is arranged opposite to the wall portion, and a projection of the insulating member covers the pressure relief groove.

4. The battery cell according to claim 3, wherein: Along the first direction, the projection of the second pressure relief area covers the projection of the first pressure relief area.

5. The battery cell according to claim 3 or 4, wherein: Along the first direction, a projection of the second pressure relief area covers the pressure relief groove.

6. The battery cell according to any one of claims 3 to 5, wherein: The insulating member is provided with a weak area, and the weak area is provided along an edge of the second pressure relief area.

7. The battery cell according to claim 6, wherein: The weak area is arranged around an outer side of a projection of the first pressure relief area on the insulating member along the first direction.

8. The battery cell according to claim 7, wherein: The pressure relief groove is opened in the wall portion and is arranged along the edge of the first pressure relief area. The weak area is arranged around the outside of the projection of the pressure relief groove on the insulating member along the first direction.

9. The battery cell according to claim 7, wherein: The battery cell includes a pressure relief member, a pressure relief hole is opened on the wall portion, the pressure relief member covers the pressure relief hole, the pressure relief groove is opened in the pressure relief member, and the weak area is arranged around the outside of the projection of the pressure relief groove on the insulating member along the first direction.

10. The battery cell according to claim 9, wherein: The weak area is arranged around an outer side of a projection of the pressure relief hole on the insulating member along the first direction.

11. The battery cell according to any one of claims 6 to 10, wherein: The weakened area includes a plurality of weakened segments, and the plurality of weakened segments are arranged at intervals along the circumference of the second pressure relief region.

12. The battery cell according to claim 11, wherein: The weak section is in a strip shape, and the width of the weak section is D1, satisfying: D1≤2mm.

13. The battery cell according to claim 11, wherein: Along the circumference of the second pressure relief area, the distance between two adjacent weak sections is D2, satisfying: D2≤10 mm.

14. The battery cell according to any one of claims 6 to 13, wherein: In a direction perpendicular to the first direction, a distance D3 between the weak area and the first pressure relief area satisfies: D3≤3 mm.

15. The battery cell according to any one of claims 6 to 10, wherein: The weak area is a closed structure extending along a closed track.

16. The battery cell according to any one of claims 6 to 15, wherein: The insulating member is provided with notches, grooves or through holes to form the weak areas.

17. The battery cell according to any one of claims 6 to 15, wherein: The melting point of the weak area is lower than the melting point of the insulating member.

18. The battery cell according to any one of claims 6 to 15, wherein: The insulating member is provided with notches, grooves or through holes, and the notches, grooves or through holes are filled with fillers, and the melting point of the fillers is lower than the melting point of the insulating member.

19. The battery cell according to claim 16 or 18, wherein: The insulating member is provided with notches or grooves to form the weak area. The insulating member has a first surface facing the wall portion, and the notches or grooves are provided on the first surface.

20. The battery cell according to claim 19, wherein The weak area includes a plurality of slot segments and a plurality of hole segments, and the slot segments and the hole segments are alternately arranged along the circumference of the second pressure relief area; Along the first direction, the insulating member has a first surface and a second surface opposite to each other, the slot section is recessed from the first surface toward the second surface, and the hole section passes through the first surface and the second surface.

21. The battery cell according to any one of claims 1 to 20, wherein: The insulating member is provided with a groove, and the bottom wall of the groove forms the second pressure relief area.

22. The battery cell according to any one of claims 1 to 20, wherein: The melting point of the second pressure relief area is lower than the melting point of the insulating member.

23. The battery cell according to claim 22, wherein: The melting point of the second pressure relief area is M, which satisfies the following conditions: 80°C≤M≤180°C.

24. The battery cell according to any one of claims 1 to 23, wherein: The insulating member is provided with a plurality of second pressure relief areas, at least some of which are configured to open when the battery cell experiences thermal runaway; Along a first direction, the insulating member is arranged opposite to the wall portion, and a projection of the first pressure relief area on the insulating member along the first direction covers at least a portion of the second pressure relief area.

25. The battery cell according to claim 24, wherein The first portion of the second pressure relief area is located within the projection range of the first pressure relief area on the insulating member along the first direction, and the second portion of the second pressure relief area is located outside the projection range of the first pressure relief area on the insulating member along the first direction.

26. The battery cell according to claim 25, wherein: Along the first direction, the insulating member has a first surface facing the wall portion, and a vent groove is provided on the first surface. The vent groove is used to guide gas from the second pressure relief area of ​​the second portion to the first pressure relief area when the battery cell thermally runs away.

27. The battery cell according to claim 26, wherein: The exhaust groove extends to the second portion of the second pressure relief area, and a projection of the first pressure relief area on the insulating member along the first direction covers a portion of the exhaust groove.

28. The battery cell according to any one of claims 24 to 27, wherein: The insulating member is provided with a plurality of weak areas, each of the weak areas corresponds to the second pressure relief area one by one, and the weak areas are provided along an edge of the second pressure relief area.

29. The battery cell according to claim 1, wherein A through hole is formed on the insulating member, and an area defined by a peripheral wall of the through hole serves as the second pressure relief area.

30. The battery cell according to any one of claims 1 to 29, wherein: The insulating member is a flat plate structure.

31. The battery cell according to claim 30, wherein: The thickness of the insulating member is N, which satisfies 0.5 mm ≤ N ≤ 10 mm.

32. The battery cell according to any one of claims 1 to 31, wherein: The battery cell includes an electrode terminal. The housing has a first wall. The electrode terminal is disposed on the first wall. The electrode terminal is electrically connected to the electrode assembly. The first wall and the wall portion are different walls.

33. A battery, wherein: include: A battery cell according to any one of claims 1 to 32.

34. An electrical device, wherein: The battery as claimed in claim 33 is used to provide electrical energy to the electrical device.

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