Battery cell, battery device, and electric device

Abstract

A battery cell (20), a battery device (10), and an electric device. The battery cell (20) comprises: a casing (211) having a first wall (201), wherein the first wall (201) is provided with a pressure relief hole (202); an electrode assembly (22) accommodated in the casing (211); a pressure relief mechanism (213) covering the pressure relief hole (202); and a support structure (215) fixed to the side of the first wall (201) facing the electrode assembly (22). The pressure relief mechanism (213) is located on the side of the support structure (215) away from the electrode assembly (22), and the pressure relief mechanism (213) is welded to at least one of the support structure (215) and the first wall (201). The obtained battery cell (20), the battery device (10), and the electric device can improve the processing efficiency and stability of the battery cell (20).

Description

Battery cell, battery device and electric equipment TECHNICAL FIELD

[0001] The present application relates to the field of battery, more particularly, to a battery cell, a battery device and an electric equipment. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. In this case, electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development. In the development of battery technology, in addition to improving the performance of the battery device, how to improve the processing efficiency and service life of the battery device while ensuring the use safety of the battery device is also an issue that cannot be ignored.

[0003] SUMMARY

[0004] The embodiments of the present application provide a battery cell, a battery device and an electric equipment, which can improve the processing efficiency and stability of the battery cell.

[0005] In a first aspect, a battery cell is provided, comprising: a shell having a first wall, the first wall being provided with a pressure relief hole; an electrode assembly accommodated in the shell; a pressure relief mechanism covering the pressure relief hole; a support structure fixed to a side of the first wall facing the electrode assembly, the pressure relief mechanism being located on a side of the support structure facing away from the electrode assembly, and the pressure relief mechanism being welded to at least one of the support structure and the first wall.

[0006] Therefore, the battery cell of the embodiments of the present application can play a positioning role in the fixed connection process of the pressure relief mechanism and the first wall, and the support structure can also be used to realize the connection and fixation between the pressure relief mechanism and the first wall, which can effectively improve the processing efficiency of the battery cell. In addition, the support structure can also be used to support the pressure relief mechanism and the first wall, increase the structural strength and stability between the first wall and the pressure relief mechanism, and especially in the use process of the battery cell, the battery cell will swell, the support structure can be used to resist deformation, reduce the cracking between the pressure relief mechanism and the first wall caused by the swelling of the battery cell, and improve the stability of the battery cell.

[0007] In some embodiments, the support structure and the first wall are fixed by welding or by adhesion, which is simple to operate, stable in structure and easy to implement.

[0008] In some embodiments, the materials of the pressure relief mechanism, the support structure and the first wall all include iron, copper or titanium. In one aspect, the pressure relief mechanism, the support structure and the first wall have the same material, facilitating the mutual fixation among the three by welding; in another aspect, the materials of iron, copper or titanium can improve the structural strength of the pressure relief mechanism, the support structure and the first wall, while reducing the thickness of the pressure relief mechanism, the support structure and the first wall, thereby improving the energy density of the battery cell. Moreover, since the strength of these materials is large, the first wall is difficult to process into a stepped structure by stamping or the like, and therefore the pressure relief mechanism is difficult to install on the stepped structure of the first wall. In the process of fixing the pressure relief mechanism and the first wall by seam welding or penetration welding, the support structure is needed to support the welding area of the pressure relief mechanism and the first wall, and can also reduce the phenomenon of laser leakage between the pressure relief mechanism and the first wall due to the existence of a gap in the welding process, thereby improving the welding strength.

[0009] In some embodiments, the thickness of the shell is in the range of [0.075mm, 0.4mm]; and / or the thickness of the pressure relief mechanism is in the range of [0.075mm, 0.4mm].

[0010] In some embodiments, the thickness of the shell is in the range of [0.075mm, 0.25mm]; and / or the thickness of the pressure relief mechanism is in the range of [0.075mm, 0.25mm].

[0011] The thickness of the shell is greater than or equal to 0.075mm, which is convenient for processing and can improve the structural strength of the shell, thereby improving the structural stability of the battery cell. The thickness of the shell is less than or equal to 0.4mm, or further, the thickness of the shell is less than or equal to 0.25mm, which can reduce the volume of the battery cell, and can effectively reduce the weight of the battery cell and improve the energy density of the battery cell. For example, the material of the shell can include iron, copper or titanium, so as to meet the design requirements of the thickness of the shell. The thickness of the pressure relief mechanism is greater than or equal to 0.075mm, which is convenient for processing and can improve the structural strength of the pressure relief mechanism as a whole, thereby improving the structural stability of the battery cell. The thickness of the pressure relief mechanism is less than or equal to 0.4mm, or further, the thickness of the pressure relief mechanism is less than or equal to 0.25mm, which can reduce the volume occupied by the pressure relief mechanism, and can effectively reduce the weight of the battery cell and improve the energy density of the battery cell.

[0012] In some embodiments, the battery cell further comprises a protection member fixed to a side of the first wall facing the electrode assembly, surfaces of the support structure and the pressure relief mechanism facing the electrode assembly are protruded from a surface of the first wall facing the electrode assembly, and a surface of the protection member facing the electrode assembly is protruded from the surfaces of the support structure and the pressure relief mechanism facing the electrode assembly. This can reduce the influence of the components inside the battery cell on the support structure and the pressure relief mechanism, and improve the reliability of the pressure relief mechanism and the battery cell.

[0013] In some embodiments, the protection member comprises a first part and a second part arranged in a spaced manner, and the pressure relief mechanism and the support structure are located between the first part and the second part. Arranging the first part and the second part in a spaced manner can reduce the processing difficulty of the protection member. In particular, when the area of the first wall is limited, there may be a part of the area around the pressure relief mechanism that is too small in size. In this part of the area, the protection member is not arranged, which can reduce the processing difficulty of the protection member. In addition, the pressure relief mechanism is located between the first part and the second part, which can still effectively protect the pressure relief mechanism.

[0014] In some embodiments, the protection member is provided with a relief opening for avoiding the pressure relief mechanism and the support structure. This can reduce the blocking of the pressure relief mechanism, so that the pressure relief mechanism can be actuated in time when the battery cell is in thermal runaway.

[0015] In some embodiments, the protection member is provided with a groove with an opening facing the pressure relief mechanism, the groove is used to accommodate the pressure relief mechanism and the support structure, a thinned area corresponding to the pressure relief mechanism is arranged at the bottom of the groove, and the thickness of the thinned area is smaller than the thickness of other areas of the bottom of the groove. On the one hand, the internal space of the groove can be used to avoid the pressure relief mechanism and the support structure. The thinned area arranged at the bottom wall of the groove can be damaged in time when the battery cell is in thermal runaway, which can reduce the influence of the bottom wall of the groove on the pressure relief mechanism, so that the pressure relief mechanism can be damaged in time and the pressure inside the battery cell can be released in time. In addition, the surface of the protection member facing the inside of the battery cell is a continuous plane without discontinuous areas, so that the electrode assembly can enter the housing more smoothly and continuously, and the installation efficiency can be improved.

[0016] In some embodiments, the pressure relief mechanism, the inner wall of the pressure relief hole and the support structure are connected by the same weld seam, which is located on the side of the support structure away from the electrode assembly. In this way, the support structure, the first wall and the pressure relief mechanism can be fixed by welding at the same time, which is efficient and can improve the processing efficiency of the battery cell. Moreover, the connecting part is directly welded to the inner wall of the pressure relief hole, which can minimize the gap between the connecting part of the pressure relief mechanism and the inner wall of the pressure relief hole, thereby improving the sealing and reliability of the battery cell.

[0017] In some embodiments, the pressure relief mechanism and the support structure are connected by the same weld seam, and the first wall and the support structure are connected by the same weld seam. The weld seam between the pressure relief mechanism and the support structure is different from the weld seam between the first wall and the support structure. In this way, the relative fixation between the pressure relief mechanism and the first wall is achieved through the support structure, and the fixation method is more flexible.

[0018] In some embodiments, the pressure relief mechanism, the support structure and the first wall are stacked along the thickness direction of the first wall, and the pressure relief mechanism, the support structure and the first wall are connected by the same weld seam. This not only facilitates processing, but also improves the structural strength and reliability of the battery cell.

[0019] In some embodiments, the pressure relief mechanism, the support structure and the first wall have at least one weld seam, and along the thickness direction of the first wall, the orthographic projection of the at least one weld seam towards the outer surface of the support structure is located in the middle region of the outer surface of the support structure. The outer surface of the support structure is the surface of the support structure away from the electrode assembly. In this way, the outer surface of the support structure can cover the at least one weld seam between the pressure relief mechanism, the support structure and the first wall, and the at least one weld seam will not exceed the outer surface of the support structure, thereby increasing the stability of the support structure and improving the stability of the battery cell.

[0020] In some embodiments, along the thickness direction of the first wall, the orthographic projection of the at least one weld seam towards the outer surface of the support structure is symmetrically distributed relative to the center line of the outer surface of the support structure. In this way, the at least one weld seam is evenly distributed on the surface of the support structure, reducing the risk of the weld seam deviating from the outer surface of the support structure and improving the structural stability and reliability.

[0021] In some embodiments, the side of the weld seam towards the electrode assembly does not exceed the surface of the support structure towards the electrode assembly, i.e. the support structure will not be welded through during the welding process, thereby preventing damage to other components inside the battery cell, improving welding efficiency and welding effect, and thereby improving the processing yield and structural stability of the battery cell.

[0022] In some embodiments, the base material of the pressure relief mechanism is iron; the pressure relief mechanism comprises a weak portion configured to be destroyed to release the pressure when the pressure inside the shell reaches a threshold value, a body portion located in the area surrounded by the weak portion, and a connecting portion located outside the weak portion and used to connect the first wall; the body portion is a protruding structure protruding towards the direction close to the electrode assembly or the direction away from the electrode assembly.

[0023] During the use of the battery cell, the electrode assembly repeatedly expands and shrinks, and the weak portion of the pressure relief mechanism is repeatedly stretched and shrunk, which is prone to fatigue; the body portion protrudes relative to the weak portion, whether the body portion protrudes towards the inside or outside of the battery cell, it can play a buffering role and can bear part of the stress, reduce the deformation of the weak portion, and reduce the fatigue of the weak portion. In addition, along the thickness direction of the pressure relief mechanism, the pressure inside the battery cell repeatedly increases and decreases, and the middle region of the flat pressure relief mechanism will repeatedly protrude and recess towards the inside and outside of the battery cell, which will also cause the weak portion of the pressure relief mechanism to be repeatedly bent and prone to fatigue; when the body portion protrudes relative to the weak portion, whether the body portion protrudes towards the inside or outside of the battery cell, it can maintain the shape of the body portion, reduce the bending angle of the weak portion, and further reduce the fatigue of the weak portion, thereby improving the service life of the pressure relief mechanism and further improving the service life of the battery cell.

[0024] In some embodiments, the connecting portion comprises a fixed region used to connect with the first wall and a transition region used to connect the fixed region with the weak portion; the fixed region is arranged parallel to the first wall, the transition region is flush with the fixed region, or the transition region protrudes towards the direction close to the electrode assembly relative to the fixed region; the body portion protrudes towards the direction close to the electrode assembly relative to the fixed region, along the thickness direction of the pressure relief mechanism, and from the pressure relief mechanism to the electrode assembly, the surface of the body portion towards the electrode assembly does not exceed the surface of the support structure towards the electrode assembly, so as to protect the body portion of the pressure relief mechanism, reduce the mutual influence between the pressure relief mechanism and the electrode assembly, and also make the support structure and the body portion of the pressure relief mechanism protruding towards the inside of the battery cell share the space in the thickness direction of the pressure relief mechanism, save the occupied space, and improve the energy density of the battery cell.

[0025] In some embodiments, the connecting portion includes a fixed region for connecting with the first wall and a transition region for connecting the fixed region with the weak portion, the fixed region is arranged parallel to the first wall, the transition region and the body portion are both protruded relative to the weak portion in a direction away from the electrode assembly, in the thickness direction of the pressure relief mechanism, and from the pressure relief mechanism to the electrode assembly, the surface of the weak portion facing the electrode assembly does not exceed the surface of the support structure facing the electrode assembly, so as to protect the weak portion of the pressure relief mechanism, reduce the mutual influence between the pressure relief mechanism and the electrode assembly, and also make the support structure and the weak portion of the pressure relief mechanism protruding into the interior of the battery monomer share the space in the thickness direction of the pressure relief mechanism, save the occupied space, and improve the energy density of the battery monomer.

[0026] In some embodiments, the thickness of the support structure is in the range of [0.4mm, 1.5mm]; or the thickness of the support structure is in the range of [0.4mm, 0.8mm]. Setting the thickness of the support structure to be greater than or equal to 0.4mm can increase the structural strength and stability of the support structure; and setting the thickness of the support structure to be less than or equal to 1.5mm, and further, setting the thickness of the support structure to be less than or equal to 0.8mm, can reduce the overall volume of the support structure, thereby reducing the internal space of the battery monomer occupied by the support structure and improving the energy density of the battery monomer.

[0027] In a second aspect, a battery device is provided, including: a plurality of battery monomers, the battery monomers being the battery monomers of the first aspect or any one of the embodiments of the first aspect.

[0028] In a third aspect, a power consuming device is provided, including: a battery device, the battery device including the battery monomers of the first aspect or any one of the embodiments of the first aspect, the battery device being configured to supply power to the power consuming device.

[0029] In some embodiments, the power consuming device is a vehicle, a ship or a spacecraft. BRIEF DESCRIPTION OF DRAWINGS

[0030] FIG. 1 is a schematic diagram of a vehicle according to an embodiment of the present application;

[0031] FIG. 2 is an exploded structural schematic diagram of a battery device according to an embodiment of the present application;

[0032] FIG. 3 is a structural schematic diagram of a battery monomer according to an embodiment of the present application;

[0033] FIG. 4 is a partially exploded structural schematic diagram of a battery monomer according to an embodiment of the present application;

[0034] FIG. 5 is a partially exploded structural schematic diagram of a shell according to an embodiment of the present application;

[0035] FIG. 6 is a side view schematic of a battery cell according to one embodiment of the application;

[0036] FIG. 7 is a partial cross-sectional view schematic of a battery cell according to one embodiment of the application;

[0037] FIG. 8 is a cross-sectional view schematic of a pressure relief mechanism during machining according to one embodiment of the application;

[0038] FIG. 9 is a top view schematic of a pressure relief mechanism during machining according to one embodiment of the application;

[0039] FIG. 10 is a cross-sectional view schematic of a pressure relief mechanism during machining according to another embodiment of the application;

[0040] FIG. 11 is a top view schematic of a pressure relief mechanism during machining according to another embodiment of the application;

[0041] FIG. 12 is another partial cross-sectional view schematic of a battery cell according to one embodiment of the application;

[0042] FIG. 13 is yet another partial cross-sectional view schematic of a battery cell according to one embodiment of the application;

[0043] FIG. 14 is a partial cross-sectional view schematic of a battery cell according to another embodiment of the application;

[0044] FIG. 15 is another partial cross-sectional view schematic of a battery cell according to another embodiment of the application;

[0045] FIG. 16 is a partial cross-sectional view schematic of a housing according to another embodiment of the application;

[0046] FIG. 17 is a partial cross-sectional view schematic of a battery cell according to yet another embodiment of the application;

[0047] FIG. 18 is a partial cross-sectional view schematic of a battery cell according to yet another embodiment of the application;

[0048] FIG. 19 is a partial cross-sectional view schematic of a battery cell according to yet another embodiment of the application;

[0049] FIG. 20 is yet another partial cross-sectional view schematic of a battery cell according to one embodiment of the application;

[0050] FIG. 21 is a partial cross-sectional view schematic of a protector according to another embodiment of the application;

[0051] FIG. 22 is a partial cross-sectional view schematic of a protector according to yet another embodiment of the application;

[0052] FIG. 23 is a structural view schematic of a protector according to one embodiment of the application;

[0053] FIG. 24 is a structural view schematic of a protector according to another embodiment of the application;

[0054] Fig. 25 is a partial cross-sectional view of a guard according to another embodiment of the present application;

[0055] Fig. 26 is another partial cross-sectional view of a guard according to another embodiment of the present application.

[0056] In the drawings, the figures are not necessarily to scale, as some components have been exaggerated for clarity. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described below with reference to the drawings.

[0058] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application.

[0059] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as those commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application and the above description of drawings are used to distinguish different objects, and are not intended to describe a specific order or primary and secondary relationship.

[0060] In the present application, the phrase "embodiment" means that the specific features, structures or characteristics described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present application can be combined with other embodiments.

[0061] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mount", "connect", "connection", "attach" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0062] The term "and / or" in the present application is only used to describe the relationship between the associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist together, and B exists alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0063] In the embodiments of the present application, the same reference signs represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device, are only exemplary and should not constitute any limitation on the present application.

[0064] In the present application, "a plurality of" refers to more than two (including two), and similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0065] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can be activated by charging after discharging.

[0066] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc. The embodiments of the present application are not limited in this regard.

[0067] In some implementations, the battery cell in the embodiments of the present application can be a metal battery, specifically, the metal battery can include a lithium metal secondary battery, a sodium metal battery, or a magnesium metal battery, etc. The embodiments of the present application are not limited in this regard.

[0068] The battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can prevent the positive and negative electrodes from short-circuiting, and at the same time, the active ions can pass through.

[0069] In some embodiments, the positive electrode can be a positive electrode sheet, which can include a positive electrode current collector and a positive electrode active material arranged on at least one surface of the positive electrode current collector.

[0070] As an example, the positive electrode current collector has two opposite surfaces in its own thickness direction, and the positive electrode active material is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0071] As an example, the positive electrode current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0072] As an example, the positive electrode active material can include at least one of a lithium-containing phosphate, a lithium transition metal oxide, and a modified compound of each thereof. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery positive electrode active material can also be used. These positive electrode active materials can be used alone only one or two or more can be used in combination. Among them, examples of the lithium-containing phosphate can include, but are not limited to, at least one of lithium iron phosphate (such as LiFeP04 (which can also be referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnP04), a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.

[0073] In some embodiments, the negative electrode can be a negative electrode sheet, which can include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0074] As an example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode active material is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0075] As an example, the negative electrode current collector can employ a metal foil, a foam metal, or a composite current collector. For example, as a metal foil, silver surface-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, a carbon electrode, carbon, nickel, or titanium, or the like can be employed. The foam metal can be a foam nickel, a foam copper, a foam aluminum, a foam alloy, or a foam carbon, or the like. The composite current collector can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, a copper alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy, or the like) on a polymer material base material (a base material of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, or the like).

[0076] As an example, the negative active material can employ a negative active material for a battery cell known in the art. As an example, the negative active material can include at least one of artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, etc.

[0077] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0078] In some embodiments, the separator is a separator film. The type of the separator film is not particularly limited in the present application, and any known porous structure separator film having good chemical stability and mechanical stability can be used.

[0079] As an example, the main material of the separator film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride, and ceramic.

[0080] In some embodiments, the separator is a solid-state electrolyte. The solid-state electrolyte is disposed between the positive electrode and the negative electrode, and functions to transport ions and separate the positive electrode and the negative electrode.

[0081] In some embodiments, the battery cell further includes an electrolyte, which functions to conduct ions between the positive electrode and the negative electrode. The type of the electrolyte is not particularly limited in the present application, and can be selected as needed. The electrolyte can be in a liquid state, a gel state, or a solid state.

[0082] In some embodiments, the electrode assembly is in a jelly-roll structure. The positive electrode sheet and the negative electrode sheet are wound to form the jelly-roll structure.

[0083] In some embodiments, the electrode assembly is in a stack structure.

[0084] As an example, a plurality of positive electrode sheets and a plurality of negative electrode sheets can be alternately stacked.

[0085] As an example, a plurality of positive electrode sheets can be provided, and the negative electrode sheet can be folded to form a plurality of folded segments stacked one on another, with one positive electrode sheet interposed between adjacent folded segments.

[0086] As an example, both the positive electrode sheet and the negative electrode sheet can be folded to form a plurality of folded segments stacked one on another.

[0087] As an example, a plurality of separators can be provided, each interposed between any adjacent positive electrode sheet or negative electrode sheet.

[0088] As an example, the separators can be continuously provided, and can be interposed between any adjacent positive electrode sheet or negative electrode sheet by being folded or wound.

[0089] In some embodiments, the electrode assembly can have a cylindrical shape, a flat shape, or a polygonal shape, etc.

[0090] In some embodiments, the electrode assembly is provided with tabs, which can conduct current out of the electrode assembly. The tabs include positive and negative tabs.

[0091] In some embodiments, the battery cell can include a housing. The housing is used to encapsulate components such as the electrode assembly and electrolyte. The housing can be a steel case, an aluminum case, a plastic case (such as polypropylene), a composite metal case (such as a copper-aluminum composite case), or an aluminum-plastic film, etc. The housing includes a case and a cover plate.

[0092] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or other shapes of battery cells, including a square battery cell, a blade battery cell, a multi-prismatic battery cell, such as a hexagonal battery cell, etc., without particular limitation.

[0093] The battery device mentioned in the embodiments of the present application can 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 a mixed connection through a busbar component.

[0094] In some embodiments, the battery device can be a battery module, and when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0095] In some embodiments, the battery device can be a battery pack, which includes a box and battery cells, and the battery cells or battery modules are contained in the box.

[0096] In some embodiments, the box can be part of the chassis structure of a vehicle. For example, part of the box can be at least part of the floor of the vehicle, or part of the box can be at least part of the cross beams and longitudinal beams of the vehicle.

[0097] The development of battery technology needs to consider various design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge-discharge rate, in addition to processing efficiency and safety. For a battery device, the main safety hazard comes from the charging and discharging process. In order to improve the safety performance of the battery device, a pressure relief mechanism is generally provided for the battery cell contained therein. The pressure relief mechanism refers to an element or component that is actuated to release the internal pressure or temperature when the internal pressure or temperature of the battery cell reaches a predetermined threshold. Therefore, the installation and use of the pressure relief mechanism will affect the battery cell.

[0098] The battery monomer provided by the embodiment of the application comprises a shell, an electrode assembly and a pressure relief mechanism. The shell has a first wall provided with a pressure relief hole; the electrode assembly is accommodated in the shell, and the pressure relief mechanism covers the pressure relief hole. The battery monomer further comprises a support structure fixed to a side of the first wall facing the electrode assembly, the pressure relief mechanism is located on a side of the support structure facing away from the electrode assembly, and the pressure relief mechanism is welded to at least one of the support structure and the first wall. In one aspect, the support structure can play a role in positioning during the fixed connection of the pressure relief mechanism and the first wall, and the support structure can also be used to realize the fixed connection between the pressure relief mechanism and the first wall, which can effectively improve the processing efficiency of the battery monomer. In another aspect, the support structure can also be used to support the pressure relief mechanism and the first wall, increase the structural strength and stability between the first wall and the pressure relief mechanism, and especially during the use of the battery monomer, the battery monomer will swell, the support structure can be used to resist deformation, reduce the cracking between the pressure relief mechanism and the first wall caused by the swelling of the battery monomer, and improve the stability of the battery monomer.

[0099] The technical solutions described in the embodiments of the application are applicable to various electric equipment using battery devices.

[0100] The electric equipment can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The vehicle can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile or a range extended automobile, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The electric toy includes a fixed or mobile electric toy, for example, a game machine, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator and an electric planer, etc. The embodiments of the application do not specially limit the above electric equipment.

[0101] The following embodiments take the vehicle as an example for convenient description.

[0102] For example, as shown in FIG. 1, a schematic diagram of a structure of a vehicle 1 according to an embodiment of the present application, the vehicle 1 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or a range extended vehicle, etc. The vehicle 1 can be provided with a motor 40, a controller 30 and a battery device 10 inside, the controller 30 is used to control the power supply of the battery device 10 to the motor 40. For example, the battery device 10 can be arranged at the bottom, the front or the rear of the vehicle 1. The battery device 10 can be used for power supply of the vehicle 1, for example, the battery device 10 can be used as the operating power source of the vehicle 1, which is used for the circuit system of the vehicle 1, for example, for the power demand of the vehicle 1 during starting, navigation and operation. In another embodiment of the present application, the battery device 10 can not only be used as the operating power source of the vehicle 1, but also be used as the driving power source of the vehicle 1, which can replace or partially replace the fuel or natural gas to provide driving power for the vehicle 1.

[0103] For example, FIG. 2 shows a schematic diagram of part of the structure of the battery device 10 according to an embodiment of the present application. As shown in FIG. 2, the battery device 10 according to an embodiment of the present application can include a plurality of battery monomers 20 to meet different power requirements. The shape of the battery monomer 20 according to an embodiment of the present application can be set according to actual application. For example, the battery monomer 20 can be cylindrical as shown in FIG. 2, or can be a cuboid or other shape different from that shown in FIG. 2, which is not limited in the present application.

[0104] It should be understood that, as shown in FIG. 2, the battery device 10 according to an embodiment of the present application can also include a box 11, which can be used to accommodate a plurality of battery monomers 20. The box 11 according to an embodiment of the present application is hollow inside, and a plurality of battery monomers 20 are accommodated in the box 11. The box 11 can include two parts, which are referred to as first box part 111 and second box part 112 respectively, and the first box part 111 and the second box part 112 are buckled together. The shape of the first box part 111 and the second box part 112 can be determined according to the shape of the components accommodated inside, for example, according to the shape of the combination of a plurality of battery monomers 20 accommodated inside, at least one of the first box part 111 and the second box part 112 has an opening. For example, as shown in FIG. 2, the first box part 111 and the second box part 112 can both be hollow cuboids and each have an opening face, the opening of the first box part 111 and the opening of the second box part 112 are oppositely arranged, and the first box part 111 and the second box part 112 are buckled to form a box 11 with a closed cavity, which can be used to accommodate a plurality of battery monomers 20. A plurality of battery monomers 20 are placed in the box 11 formed by buckling the first box part 111 and the second box part 112 after being combined in parallel or in series or in a hybrid combination.

[0105] For another example, unlike the case shown in FIG. 2, only one of the first case portion 111 and the second case portion 112 can be a hollow cuboid with an opening, and the other can be a plate-shaped portion to cover the opening. For example, the second case portion 112 is a hollow cuboid with an opening, and the first case portion 111 is a plate-shaped portion. In this case, the first case portion 111 covers the opening of the second case portion 112 to form a case 11 with a closed cavity, which can be used to accommodate a plurality of battery cells 20.

[0106] In some embodiments, the battery device 10 can further include other components. For example, the battery device 10 can further include a busbar component, which can be used to achieve electrical connection between a plurality of battery cells 20, such as parallel connection or series connection or hybrid connection. Specifically, the busbar component can achieve electrical connection between the battery cells 20 by connecting the electrode terminals 214 of the battery cells 20; or the busbar component can also achieve electrical connection between the battery cells 20 by connecting other components of the battery cells 20. The busbar component can be fixed to the corresponding components of the battery cells 20 by welding, such as the electrode terminals 214, the sealing structure or the shell, etc. The embodiments of the present application are not limited thereto.

[0107] FIG. 3 shows a structural schematic diagram of a battery cell 20 according to an embodiment of the present application; FIG. 4 shows an exploded structural schematic diagram of a battery cell according to an embodiment of the present application, which can be an exploded structural schematic diagram of the battery cell 20 shown in FIG. 3; FIG. 5 shows a partial exploded structural schematic diagram of a battery cell 20 according to an embodiment of the present application, which can be a possible exploded structural schematic diagram of the shell 211 of the battery cell 20 shown in FIGS. 3 and 4; FIG. 6 shows a side view schematic diagram of a battery cell 20 according to an embodiment of the present application, which can be a side view schematic diagram of the battery cell 20 shown in FIGS. 3 to 5; and FIG. 7 shows a partial sectional view schematic diagram of a battery cell 20 according to an embodiment of the present application, which can be a partial area of a sectional view along the direction of A-A’ shown in FIG. 6.

[0108] As shown in FIGS. 3 to 7, the battery cell 20 according to an embodiment of the present application can include a shell 211, an electrode assembly 22, a pressure relief mechanism 213 and a support structure 215. The shell 211 has a first wall 201 provided with a pressure relief hole 202; the electrode assembly 22 is accommodated in the shell 211; the pressure relief mechanism 213 covers the pressure relief hole 202; and the support structure 215 is fixed to the side of the first wall 201 facing the electrode assembly 22, the pressure relief mechanism 213 is located on the side of the support structure 215 facing away from the electrode assembly 22, and the pressure relief mechanism 213 is welded to at least one of the support structure 215 and the first wall 201.

[0109] It should be understood that the shape of the battery cell 20 in the embodiments of the present application can be flexibly set according to actual application, that is, the shell 21 of the battery cell 20 can be any polyhedral structure, for example, can be set as a cuboid or a cylinder, etc. For example, as shown in FIGS. 3 to 7, the shape of the outside of the battery cell 20 can be the same as or different from the shape of the electrode assembly 22 inside. For example, if the electrode assembly 22 is a cylindrical structure, the shell 21 of the battery cell 20 can also be a cylindrical structure, or can also be a cuboid structure; if the electrode assembly 22 is a cuboid structure, the shell 21 can also be a cuboid structure in general, but the embodiments of the present application are not limited thereto.

[0110] In the embodiments of the present application, the battery cell 20 includes a shell 211, for example, the shell 21 can include the shell 211. Specifically, the shell 211 is a hollow structure with an opening 2111, and the electrode assembly 22 is accommodated in the shell 211; the battery cell 20 can also include a cover plate 212, which is used to cover the opening 2111 of the shell 211 to isolate the external environment.

[0111] In some embodiments, the number of the cover plates 212 is related to the openings 2111 of the shell 211. If the shell 211 is a hollow structure with an opening 2111 formed at one end, the cover plate 212 can be provided as one; or, differently, for example, as shown in FIGS. 3 to 7, the shell 211 can be a hollow structure with openings 2111 formed at opposite ends, so as to facilitate the internal electrode assembly 22 to enter the inside of the shell from any side, to provide installation efficiency, and correspondingly, the cover plates 212 can be provided as two, and the two cover plates 212 cover the openings 2111 at the two ends of the shell 211 respectively, but the embodiments of the present application are not limited thereto.

[0112] The material of the shell 211 in the embodiments of the present application can include one or more, for example, can include copper, iron, aluminum, steel, aluminum alloy, etc. The material of the cover plate 212 can also be one or more, for example, can include copper, iron, aluminum, steel, aluminum alloy, etc. Among them, the material of the cover plate 212 can be the same as or different from the material of the shell 211; the materials of different walls of the shell 211 can also be the same or different.

[0113] The shell 211 and the cover plate 212 of the embodiment of the present application are matched in shape. For example, as shown in FIGS. 3-7, the shell 211 can be a cuboid structure, and the cover plate 212 can be a rectangular plate structure matched with the shell 211. The cover plate 212 can be any wall of the shell 21, for example, the cover plate 212 can be the wall with the largest area among the walls included in the shell 21, or the wall with the smallest area, or can be another wall, and the embodiment of the present application is not limited thereto. Alternatively, the cover plate 212 can also be another structure, for example, the cover plate 212 can also be a groove structure with an opening to cover the opening 2111 of the shell 211, and the embodiment of the present application is not limited thereto.

[0114] In some embodiments, the first wall 201 can be any wall of the shell 211 or the cover plate 212. For example, the first wall 201 can be a side wall of the shell 211, that is, the first wall 201 can be a wall adjacent to the opening 2111, and the pressure relief mechanism 213 is arranged on the first wall 201. Especially in the case that the area of the cover plate 212 is limited, arranging the pressure relief mechanism 213 on the shell 211 can save the space of the cover plate 212 and facilitate processing.

[0115] For ease of illustration, the shell 21 is taken as a cuboid structure as shown in FIGS. 3-7; the shell 211 is a hollow structure with openings at opposite ends, and the first wall 201 is a side wall of the shell 211; correspondingly, the two cover plates 212 are arranged to cover the two side openings 2111 of the shell 211, for example, the sealing connection between the shell 211 and the cover plate 212 can be achieved by welding to form a closed cavity for placing the electrode assembly 22 and improve the sealing reliability.

[0116] In addition, for the rectangular battery monomer 20, three reference directions are defined in the embodiments of the present application for ease of description. The thickness direction of the battery monomer 20 is the direction Y, the height direction of the battery monomer 20 is the direction Z, and the length direction of the battery monomer 20 is the direction X, wherein the thickness direction Y, the height direction Z and the length direction X of the battery monomer 20 are perpendicular to each other, and the thickness direction Y of the battery monomer 20 is smaller than the length direction X.

[0117] In the embodiments of the present application, the first wall 201 is provided with the pressure relief hole 202, and the pressure relief mechanism 213 covers the pressure relief hole 202. The first wall 201 is provided with the pressure relief hole 202, that is, a through hole is arranged on the first wall 201 as the pressure relief hole 202, which is convenient for processing; and the pressure relief mechanism 213 arranged separately from the first wall 201 is more flexible and convenient for processing and assembly, which can improve the design flexibility of the pressure relief mechanism 213.

[0118] It should be understood that the pressure relief mechanism 213 of the embodiments of the present application refers to an element or component that is actuated when the internal pressure or temperature of the battery cell 20 reaches a predetermined threshold value to release the internal pressure or temperature. The threshold value is designed differently according to different design requirements. The threshold value can depend on the material of one or more of the positive electrode plate, the negative electrode plate, the electrolyte, and the separator in the battery cell 20.

[0119] The "actuation" mentioned in the present application refers to the pressure relief mechanism 213 generating an action or being activated to a certain state, so that the internal pressure and temperature of the battery cell 20 can be released. The action generated by the pressure relief mechanism 213 can include but is not limited to at least one of the following: the pressure relief mechanism 213 is broken, cracked, torn, or opened, etc. When the pressure relief mechanism 213 is actuated, the high-temperature and high-pressure substances inside the battery cell 20 will be discharged outward from the actuated part as the discharge. In this way, the battery cell 20 can be relieved of pressure and temperature in a controllable manner, thereby avoiding potential more serious accidents.

[0120] The discharge from the battery cell 20 mentioned in the present application includes but is not limited to the following: electrolyte, dissolved or split positive and negative electrode plates, fragments of the separator, high-temperature and high-pressure gas generated by the reaction, flame, etc.

[0121] It should be understood that the support structure 215 is fixed to the side of the first wall 201 facing the electrode assembly 22, and the pressure relief mechanism 213 is located on the side of the support structure 215 away from the electrode assembly 22, that is, the support structure 215 is located on the side of the first wall 201 and the pressure relief mechanism 213 facing the electrode assembly 22, so that the support structure 215 can save the external space of the battery cell 20, and facilitate the fixed connection between the pressure relief mechanism 213 and the first wall 201.

[0122] The pressure relief mechanism 213 of the embodiments of the present application is welded to at least one of the support structure 215 and the first wall 201. For example, the pressure relief mechanism 213 can be welded to the support structure 215, and the support structure 215 can be fixed with the first wall 201, thereby realizing the relative fixation between the pressure relief mechanism 213 and the first wall 201. For another example, the pressure relief mechanism 213 can also be welded and fixed with the first wall 201, and the first wall 201 and the support structure 215 are fixed with each other, thereby realizing the relative fixation among the pressure relief mechanism 213, the first wall 201, and the support structure 215. For another example, the pressure relief mechanism 213 can also be welded and fixed with the support structure 215 and the first wall 201 at the same time, and the embodiments of the present application are not limited thereto.

[0123] On one hand, the support structure 215 can play a role in positioning during the fixed connection of the pressure relief mechanism 213 and the first wall 201, and can also be used to achieve the fixed connection between the pressure relief mechanism 213 and the first wall 201, which can effectively improve the processing efficiency of the battery monomer 20; on the other hand, the support structure 215 can also be used to support the pressure relief mechanism 213 and the first wall 201, increase the structural strength and stability between the first wall 201 and the pressure relief mechanism 213, especially during the use of the battery monomer 20, the battery monomer 20 will swell, the support structure 215 can also be used to resist deformation, reduce the cracking between the pressure relief mechanism 213 and the first wall 201 caused by the swelling of the battery monomer 20, and improve the stability of the battery monomer 20.

[0124] It should be understood that the shell 21 of the embodiment of the present application is internally used to accommodate the electrode assembly, and the electrode assembly 22 is a component that undergoes an electrochemical reaction in the battery monomer 20. According to actual use requirements, the electrode assembly 22 in the battery monomer 20 can be provided as one or more. For any one electrode assembly 22, the electrode assembly 22 can include a tab 222 and a tab main body 221. Specifically, as shown in FIGS. 3 to 7, the electrode assembly 22 can include at least two tabs 222, which can include at least one positive tab and at least one negative tab. The positive tab can be formed by laminating the portion of the positive tab that is not coated with a positive active material layer, and the portion of the positive tab coated with the positive active material layer can form the tab main body 221 by winding or lamination. The negative tab can be formed by laminating the portion of the negative tab that is not coated with a negative active material layer, and the portion of the negative tab coated with the negative active material layer can form the tab main body 221 by winding or lamination.

[0125] The plurality of tabs 222 of the electrode assembly 22 of the embodiment of the present application can be located at the same or different end faces of the electrode assembly 22. For example, the electrode assembly 22 can include two tabs 222 of opposite polarity, which can be located at the same end face, or the two tabs 222 can be provided at different end faces, for example, the two tabs 222 can be located at opposite end faces, and the embodiment of the present application is not limited thereto. For ease of illustration, as shown in FIGS. 3 to 7, the embodiment of the present application mainly takes the example that the electrode assembly 22 includes the tabs 222 of opposite polarity located at opposite end faces of the electrode assembly 22.

[0126] In some embodiments, the battery cell 20 of the embodiments of the present application can further be provided with electrode terminals 214 on the shell 21 of the battery cell 20, the electrode terminals 214 being used to be electrically connected with the electrode assembly 22 to output the electric energy of the battery cell 20. As shown in FIGS. 3 to 7, the battery cell 20 can include at least two electrode terminals 214, including at least one positive electrode terminal and at least one negative electrode terminal. Each electrode terminal 214 is used to be electrically connected with a corresponding tab 222. For example, each electrode terminal 214 can be electrically connected with a corresponding tab 222 through a connecting member. For example, the positive electrode tab of the electrode assembly 22 can be connected with the positive electrode terminal through one connecting member, and the negative electrode tab of the electrode assembly 22 can be connected with the negative electrode terminal through another connecting member.

[0127] The at least two electrode terminals 214 of the battery cell 20 can be arranged on the same wall or different walls of the battery cell 20. For example, the positions of the electrode terminals 214 can be arranged according to the positions of the tabs 222 of the electrode assembly 22. For example, as shown in FIGS. 3 to 7, the embodiments of the present application mainly take the battery cell 20 including two electrode terminals 214 as an example, and the two electrode terminals 214 are arranged on the opposite two walls of the shell 21 of the battery cell 20.

[0128] The support structure 215 of the embodiments of the present application will be described below in combination with the accompanying drawings.

[0129] It should be understood that the support structure 215 and the first wall 201 are fixed through welding or through adhesion, which is simple to operate, stable in structure, and easy to implement.

[0130] It should be understood that the materials of the pressure relief mechanism 213, the support structure 215 and the first wall 201 of the embodiments of the present application can be set according to actual application. In some embodiments, the materials of the pressure relief mechanism 213, the support structure 215 and the first wall 201 all include iron, copper or titanium. For example, the materials of the pressure relief mechanism 213, the support structure 215 and the first wall 201 are steel, copper alloy or titanium alloy, etc. In one aspect, the pressure relief mechanism 213, the support structure 215 and the first wall 201 have the same material, which facilitates the mutual fixation of the three by welding; on the other hand, the materials can improve the structural strength of the pressure relief mechanism 213, the support structure 215 and the first wall 201, while reducing the thickness of the pressure relief mechanism 213, the support structure 215 and the first wall 201, thereby improving the energy density of the battery monomer 20. Moreover, since iron, copper or titanium has high strength, and the thickness of the pressure relief mechanism 213, the support structure 215 and the first wall 201 is relatively thin, it is difficult to obtain a stepped structure of the first wall 201 by stamping or other methods, so it is difficult to install the pressure relief mechanism 213 on the stepped structure of the first wall 201, and in the process of fixing the pressure relief mechanism 213 and the first wall 201 by seam welding or penetration welding, the welding area of the pressure relief mechanism 213 and the first wall 201 is supported by the support structure 215, which can reduce the phenomenon of laser leakage caused by the gap between the pressure relief mechanism 213 and the first wall 201 during welding, and improve the welding strength.

[0131] It should be understood that the size of the pressure relief mechanism 213, the support structure 215 and the first wall 201 of the embodiments of the present application can be flexibly set according to actual application.

[0132] For example, the thickness T1 of the shell 211 is in the range of [0.075mm, 0.4mm], or the thickness T1 of the shell 211 is in the range of [0.075mm, 0.25mm]. In one aspect, the thickness T1 of the shell 211 is greater than or equal to 0.075mm, which facilitates processing and can improve the structural strength of the shell 211, thereby improving the structural stability of the battery monomer 20. On the other hand, the thickness T1 of the shell 211 is less than or equal to 0.4mm, or further, the thickness T1 of the shell 211 is less than or equal to 0.25mm, which can reduce the volume of the battery monomer 20, and also effectively reduce the weight of the battery monomer 20 and improve the energy density of the battery monomer 20. For example, the material of the shell 211 can include steel to meet the design requirements of the thickness T1 of the shell 211.

[0133] In some embodiments, the thickness T1 of the shell 211 can be any value or between any two values of 0.075 mm, 0.1 mm, 0.125 mm, 0.15 mm, 0.175 mm, 0.2 mm, 0.225 mm, 0.25 mm, 0.275 mm, 0.3 mm, 0.325 mm, 0.35 mm, 0.375 mm, and 0.4 mm.

[0134] It should be understood that the thickness T1 of the shell 211 of the embodiments of the present application can refer to the average thickness of at least a partial region of the shell 211. For example, the thickness T1 of the shell 211 can refer to the average thickness of the entire region of the shell 211, especially in the case that the shell 211 is relatively flat and the thickness is relatively uniform, that is, the thickness of most regions of the shell 211 is substantially equal or has a small difference, or the thickness of the entire region of the shell 211 is substantially equal or has a small difference, then the average thickness of the entire region of the shell 211 can be determined as T1. Alternatively, the thickness T1 of the shell 211 can also refer to the average thickness of a local region of the shell 211, for example, the thickness of the first wall 201 of the shell 211, or the average thickness of a local region of the first wall 201 close to the pressure relief mechanism 213, without being limited thereto.

[0135] It should be understood that the thickness of the pressure relief mechanism 213 of the embodiments of the present application can be set according to actual application. For example, the thickness T2 of the pressure relief mechanism 213 is in the range of [0.075 mm, 0.4 mm], or the thickness T2 of the pressure relief mechanism 213 is in the range of [0.075 mm, 0.25 mm]. On the one hand, the thickness T2 of the pressure relief mechanism 213 is greater than or equal to 0.075 mm, which is convenient for processing and can improve the overall structural strength of the pressure relief mechanism 213, thereby improving the structural stability of the battery monomer 20. On the other hand, the thickness T2 of the pressure relief mechanism 213 is less than or equal to 0.4 mm, or more further, the thickness T2 of the pressure relief mechanism 213 is less than or equal to 0.25 mm, which can reduce the volume occupied by the pressure relief mechanism 213, and can effectively reduce the weight of the battery monomer 20 and improve the energy density of the battery monomer 20.

[0136] In some embodiments, the thickness T2 of the pressure relief mechanism 213 can be any value or between any two values of 0.075 mm, 0.1 mm, 0.125 mm, 0.15 mm, 0.175 mm, 0.2 mm, 0.225 mm, 0.25 mm, 0.275 mm, 0.3 mm, 0.325 mm, 0.35 mm, 0.375 mm, and 0.4 mm.

[0137] The thickness T2 of the pressure relief mechanism 213 can be the average thickness of the pressure relief mechanism 213, or can also refer to the average thickness of a partial region of the pressure relief mechanism 213. It should be understood that the thickness of different regions of the pressure relief mechanism 213 can be the same or different. The pressure relief mechanism 213 of the embodiments of the present application will be described below with reference to the accompanying drawings.

[0138] In some embodiments, the base material of the pressure relief mechanism 213 is iron, where the "base material" refers to the material with the highest weight percentage in the material of the pressure relief mechanism 213. For example, the material of the pressure relief mechanism 213 can include at least one of the following: iron-carbon alloy, stainless steel, cast iron, and alloy steel, etc., to improve the structural strength of the pressure relief mechanism 213.

[0139] In some embodiments, the specific material of the pressure relief mechanism 213 can be set according to actual application. For example, the material of the pressure relief mechanism 213 includes stainless steel and / or carbon steel. The stainless steel pressure relief mechanism 213 has high structural strength, and can also prevent corrosion and rust, effectively improving the service life of the pressure relief mechanism 213. The carbon steel pressure relief mechanism 213 has greater structural strength, which is beneficial to improve the structural stability and reliability of the pressure relief mechanism 213. For another example, the material of the pressure relief mechanism 213 is selected to be steel, and the model of the steel can include at least one of the following: SPCC, Q195, Q215, Q235, SUS 304, SUS 316, and other modified stainless steels. These steels are easy to obtain, have strength that is easy to meet the design requirements of the battery monomer 20, and have low cost.

[0140] In some embodiments, the pressure relief mechanism 213 includes a weak portion 2132 configured to be destroyed to release pressure when the pressure inside the shell 211 reaches a threshold value, a body portion 2131 located in the region surrounded by the weak portion 2132, and a connecting portion 2133 located outside the weak portion 2132 and used to connect the first wall 201; the body portion 2131 is a protruding structure protruding towards the direction close to the electrode assembly 22 or the direction away from the electrode assembly 22.

[0141] It should be understood that the pressure relief mechanism 213 of the embodiment of the present application includes a weak portion 2132 configured to be broken to release the pressure inside the shell 211 when the pressure reaches a threshold value. The weak portion 2132 can be implemented in various ways. For example, the weak portion 2132 can be a notch or a groove, so that the thickness of the weak portion 2132 is less than that of other areas of the pressure relief mechanism 213, thereby reducing the structural strength of the weak portion 2132, so that the weak portion 2132 is more easily broken. For another example, the weak portion 2132 can also be provided with a temperature-sensitive material, so that when the temperature inside the battery monomer 20 exceeds a threshold value, the weak portion 2132 is easily broken. For ease of illustration, the embodiment is mainly described by taking the weak portion 2132 as a notch.

[0142] It should be understood that the position of the weak portion 2132 of the pressure relief mechanism 213 of the embodiment of the present application can be set according to actual application. For example, the weak portion 2132 can be annular, and the weak portion 2132 can be continuously and circumferentially arranged at the edge of the pressure relief mechanism 213, so that the weak portion 2132 is uniformly distributed, and when the battery monomer 20 occurs thermal runaway, any area of the annular weak portion 2132 can be broken, so that the pressure relief mechanism 213 timely discharges the discharge inside the battery monomer 20, reduces the risk of thermal diffusion between the plurality of battery monomers 20, and improves the reliability of the battery device 10.

[0143] The pressure relief mechanism 213 of the embodiment of the present application also includes a body portion 2131 located in the area surrounded by the weak portion 2132, and a connecting portion 2133 located outside the weak portion 2132 and used to connect the first wall 201; the body portion 2131 is a protruding structure protruding towards the direction close to the electrode assembly 22 or the direction away from the electrode assembly 22.

[0144] It should be understood that the connecting portion 2133 of the embodiment of the present application is used to connect the first wall 201, for example, the first wall 201 can include a first fixed area 203 used to fixedly connect with the connecting portion 2133, so as to realize the relative fixation between the pressure relief mechanism 213 and the first wall 201.

[0145] The body part 2131 of the embodiment of the present application is a convex structure protruding towards the direction close to the electrode assembly 22 or the direction away from the electrode assembly 22, i.e. the body part 2131 is uneven. For example, the whole area of the body part 2131 is a convex structure protruding towards the direction close to the electrode assembly 22; or the whole area of the body part 2131 is a convex structure protruding towards the direction away from the electrode assembly 22; or part of the area of the body part 2131 is a convex structure protruding towards the direction close to the electrode assembly 22 and part of the area of the body part 2131 is a convex structure protruding towards the direction away from the electrode assembly 22, for example, the body part 2131 can be a wave-shaped structure, and the embodiment of the present application is not limited thereto.

[0146] The body part 2131 is provided as a convex structure, which can effectively improve the service life of the pressure relief mechanism 213. FIG. 8 shows a cross-sectional view of the pressure relief mechanism 213 of the embodiment of the present application, and FIG. 9 shows a top view of the pressure relief mechanism 213 of the embodiment of the present application, for example, FIG. 8 and FIG. 9 can be the pressure relief mechanism 213 included in the battery monomer 20 shown in FIG. 3 to FIG. 7 of the present application; FIG. 10 shows a cross-sectional view of another pressure relief mechanism 213', and FIG. 11 shows a top view of another pressure relief mechanism 213'.

[0147] As shown in FIG. 10 and FIG. 11, for the relatively flat pressure relief mechanism 213', when the base material thereof is iron, the structural strength of the pressure relief mechanism 213' is large, and in the process of forming the notch by stamping, the notch around the formed area is subjected to the extrusion force F towards the center of the pressure relief mechanism 213'. Due to the difficulty of metal flow, the direction distribution of the deformation amount S of different areas in the notch around the formed area is uneven, some areas protrude towards the direction close to the electrode assembly 22 under the action of the extrusion force F, and some areas protrude towards the direction away from the electrode assembly 22 under the action of the extrusion force F, so that the originally flat pressure relief mechanism 213' becomes uneven, resulting in poor consistency of the explosion of the pressure relief mechanism 213' and affecting the safety and reliability of the battery device 10.

[0148] As shown in FIG. 8 and FIG. 9, the body part 2131 of the pressure relief mechanism 213 of the embodiment of the present application is a convex structure, whether the body part 2131 protrudes towards the inside or outside of the battery monomer 20, the strength of the pressure relief mechanism 213 can be enhanced. In the process of stamping the notch, the body part 2131 is subjected to the extrusion force F towards the center of the pressure relief mechanism 213, and the different areas of the body part 2131 are deformed along the direction of the convexity thereof, the direction of the deformation amount S is consistent, and then the overall shape of the pressure relief mechanism 213 is stable, which guarantees the consistency of the explosion of the pressure relief mechanism 213.

[0149] In addition, during use of the battery monomer 20, the electrode assembly 22 repeatedly expands and shrinks, the weak part 2132 of the pressure relief mechanism 213 is repeatedly stretched and shrunk, and fatigue is prone to occur; the body part 2131 protrudes relative to the weak part 2132, and no matter whether the body part 2131 protrudes towards the inside or outside of the battery monomer 20, the body part 2131 can play a buffering role and can bear part of the stress, thereby reducing the deformation of the weak part 2132 and reducing the fatigue of the weak part 2132. In addition, along the thickness direction X of the pressure relief mechanism 213, the pressure inside the battery monomer 20 repeatedly increases and decreases, and the middle region of the flat pressure relief mechanism 213' repeatedly protrudes and recesses towards the inside and outside of the battery monomer 20, which also causes the weak part of the pressure relief mechanism 213' to be repeatedly bent and prone to fatigue; in the case where the body part 2131 of the embodiment of the present application protrudes relative to the weak part 2132, no matter whether the body part 2131 protrudes towards the inside or outside of the battery monomer 20, the shape of the body part 2131 can be kept relatively stable, the bending angle of the weak part 2132 is reduced, and thus the fatigue of the weak part 2132 is reduced, the service life of the pressure relief mechanism 213 is improved, and thus the service life of the battery monomer 20 is improved.

[0150] It should be understood that the thickness T2 of the pressure relief mechanism 213 of the embodiment of the present application can refer to the thickness of the body part 2131. The body part 2131 is the middle region of the pressure relief mechanism 213, and the thickness thereof is generally uniform, so the thickness of different regions of the body part 2131 can be set to be the same or substantially the same, and the average thickness of the body part 2131 is the thickness of the body part 2131. The thickness T2 of the body part 2131 can be [0.075mm, 0.4mm].

[0151] In some embodiments, the thickness T3 of the support structure 215 can be [0.4mm, 1.5mm]. Setting the thickness T3 of the support structure 215 to be greater than or equal to 0.4mm can increase the structural strength and stability of the support structure 215; and setting the thickness T3 of the support structure 215 to be less than or equal to 1.5mm can reduce the overall volume of the support structure 215, thereby reducing the internal space of the battery monomer 20 occupied by the support structure 215 and improving the energy density of the battery monomer 20.

[0152] In some embodiments, the thickness T3 of the support structure 215 can also be set to [0.4mm, 1mm] or [0.4mm, 0.8mm]; or the thickness T3 of the support structure 215 can be any of the following values or between any two of the following values: 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm, 0.9mm, 0.95mm, 1mm and 1.5mm.

[0153] In the embodiments of the present application, the thickness T3 of the support structure 215 is generally greater than or equal to the thickness of the connecting portion 2133. In order to enable the pressure relief mechanism 213 to actuate in time when the battery cell 20 is in thermal runaway, the thickness T2 of the pressure relief mechanism 213 is generally set to be small, and the thickness of the connecting portion 2133 is also small. Therefore, the thickness T3 of the support structure 215 is set to be greater than or equal to the thickness of the connecting portion 2133, so as to improve the structural strength of the support structure 215, and reduce the deformation of the pressure relief mechanism 213 at the connecting portion 2133, and improve the structural stability of the pressure relief mechanism 213.

[0154] The measurement direction of the thickness T3 of the support structure 215 of the embodiments of the present application is consistent with the measurement direction of the thickness of the connecting portion 2133 of the pressure relief mechanism 213. For example, as shown in FIGS. 3 to 7, the thickness T3 of the support structure 215 and the thickness of the connecting portion 2133 can be measured along the thickness direction X of the first wall 201.

[0155] The thickness T3 of the support structure 215 of the embodiments of the present application can be the average thickness of the support structure 215 as a whole. For example, if the support structure 215 is a relatively flat structure as a whole, the thicknesses of different regions of the support structure 215 are relatively small, and therefore, the average thickness of the support structure 215 as a whole can be measured and determined as the thickness T3 of the support structure 215. For another example, the thickness T3 of the support structure 215 can also be the average thickness of a local region of the support structure 215 close to the connecting portion 2133. In particular, in the case where the thickness of the support structure 215 is not uniform, the thicknesses of different regions of the support structure 215 are relatively large, and therefore, the average thickness of the portion of the support structure 215 close to the connecting portion 2133 can be measured and determined as the thickness T3 of the support structure 215.

[0156] It should be understood that the relative positions among the support structure 215, the pressure relief mechanism 213, and the first wall 201 of the embodiments of the present application can be set according to actual applications. In some embodiments, the surface of the first fixed region 203 of the first wall 201 facing the support structure 215 is flush with the surface of the connecting portion 2133 facing the support structure 215, so that the first fixed region 203 and the connecting portion 2133 are both fixed on the same surface of the support structure 215, which can reduce the total thickness of the support structure 215, the first fixed region 203, and the connecting portion 2133 in the thickness direction X of the support structure 215, so as to improve the energy density of the battery monomer 20. In addition, by setting the surface of the first fixed region 203 facing the support structure 215 flush with the surface of the connecting portion 2133 facing the support structure 215, when the first fixed region 203 is attached to the surface of the support structure 215, the connecting portion 2133 can also be attached to the surface of the support structure 215, which reduces the gap between the first fixed region 203 and the support structure 215 or the gap between the connecting portion 2133 and the support structure 215, and improves the structural stability and sealing performance of the battery monomer 20.

[0157] It should be understood that, as shown in FIGS. 3 to 7, when the surface of the first fixed region 203 facing the support structure 215 is flush with the surface of the connecting portion 2133 facing the support structure 215, the first fixed region 203, the connecting portion 2133, and the support structure 215 can be fixed by various ways. For example, FIG. 12 shows another partial cross-sectional view of the battery monomer 20 of the embodiments of the present application, which can be used to show one way of fixing the first fixed region 203, the connecting portion 2133, and the support structure 215, i.e., FIG. 12 can be one possible way of fixing the first fixed region 203, the connecting portion 2133, and the support structure 215 shown in FIG. 7.

[0158] In some embodiments, the pressure relief mechanism 213, the inner wall of the pressure relief hole 202 and the support structure 215 are connected by the same weld seam, which is located on the side of the support structure 215 away from the electrode assembly 22. Specifically, as shown in FIG. 12, the connecting portion 2133 and the inner wall of the pressure relief hole 202 can be fixed by means of a butt weld, and a weld seam B is formed at the same time, and the support structure 215 is also welded and fixed on the side of the weld seam B facing the inside of the battery monomer 20. The first fixed area 203 includes the inner wall of the pressure relief hole 202, and the side surface of the connecting portion 2133 facing the inner wall of the pressure relief hole 202 is attached to the inner wall of the pressure relief hole 202, and the support structure 215 is located on the side of the connecting portion 2133 and the first fixed area 203 facing the inside of the battery monomer 20. During welding, the first fixed area 203 and the connecting portion 2133 are connected by means of a butt weld, and the support structure 215, the first fixed area 203 and the connecting portion 2133 are welded and fixed at the same time, and the weld seam B formed by welding includes the area between the connecting portion 2133 and the inner wall of the pressure relief hole 202, and the area of the support structure 215 close to the weld seam. In this way, the support structure 215, the first fixed area 203 and the connecting portion 2133 can be welded and fixed at the same time, which is efficient, and can improve the processing efficiency of the battery monomer 20; and the connecting portion 2133 is directly welded to the inner wall of the pressure relief hole 202, which can minimize the gap between the connecting portion 2133 of the pressure relief mechanism 213 and the inner wall of the pressure relief hole 202, and improve the sealing performance and reliability of the battery monomer 20.

[0159] In some embodiments, the first fixed area 203, the connecting portion 2133 and the support structure 215 are made of the same material, so as to be connected and fixed by means of the butt weld described above. For example, the first fixed area 203, the connecting portion 2133 and the support structure 215 are all made of steel; or the first fixed area 203, the connecting portion 2133 and the support structure 215 are all made of copper. On the one hand, the first fixed area 203, the connecting portion 2133 and the support structure 215 have the same material, which is convenient for welding; on the other hand, the first fixed area 203, the connecting portion 2133 and the support structure 215 can be made of steel or copper to improve the structural strength and reduce the thickness of the first fixed area 203, the connecting portion 2133 and the support structure 215, thereby improving the energy density of the battery monomer 20.

[0160] FIG. 13 shows another partial cross-sectional view of the battery monomer 20 according to an embodiment of the present application. For example, FIG. 13 can be used to show another way of fixing the pressure relief mechanism 213, the first wall 201 and the support structure 215, i.e. FIG. 13 can be another possible way of fixing the pressure relief mechanism 213, the first wall 201 and the support structure 215 shown in FIG. 7.

[0161] As shown in FIG. 13, the pressure relief mechanism 213 and the support structure 215 are connected by the same weld, and the first wall 201 and the support structure 215 are connected by the same weld. The weld between the pressure relief mechanism 213 and the support structure 215 is different from the weld between the first wall 201 and the support structure 215. Specifically, as shown in FIG. 13, the first fixed area 203 is located on the surface of the support structure 215 away from the inside of the battery monomer 20, and the two are fixed by penetrating welding to form the same weld C1. At the same time, the connecting part 2133 is also located on the surface of the support structure 215 away from the inside of the battery monomer 20, and the two are fixed by penetrating welding to form the same weld C2, and the weld C1 and the weld C2 are different welds. In this way, the relative fixation between the first fixed area 203 and the connecting part 2133 can be realized through the support structure 215, that is, the relative fixation between the pressure relief mechanism 213 and the first wall 201 is realized, and the fixation mode is more flexible.

[0162] In some embodiments, considering that the first fixed area 203 and the support structure 215 are connected by the same weld, in order to facilitate welding, the area of the first fixed area 203 and the support structure 215 used for welding with the first fixed area 203 generally includes the same material. Similarly, the connecting part 2133 and the support structure 215 are connected by the same weld, so the area of the connecting part 2133 and the support structure 215 used for welding with the connecting part 2133 generally includes the same material.

[0163] In some embodiments, the material of the first fixed area 203 includes steel, the material of the connecting part 2133 includes aluminum, the material of the support structure 215 close to the first fixed area 203 includes steel, and the material of the support structure 215 close to the connecting part 2133 includes aluminum. On the one hand, the material of the support structure 215 close to the first fixed area 203 is the same as the material of the first fixed area 203, and the material of the support structure 215 close to the connecting part 2133 is the same as the material of the connecting part 2133, which facilitates welding. On the other hand, the material of the first fixed area 203 of the first wall 201 includes steel, which can improve the structural strength and stability of the first wall 201, and the material of the connecting part 2133 of the pressure relief mechanism 213 includes aluminum, which facilitates the molding of the pressure relief mechanism 213 and improves the processing efficiency of the battery monomer 20.

[0164] In some embodiments, as shown in FIG. 13, the connecting part 2133 abuts the inner wall of the pressure relief hole 202 to minimize the gap between the connecting part 2133 of the pressure relief mechanism 213 and the inner wall of the pressure relief hole 202, thereby improving the sealing and reliability of the battery monomer 20.

[0165] In some embodiments, the surface of the first fixed region 203 away from the interior of the battery cell is flush with the surface of the connecting portion 2133 away from the interior of the battery cell, so as to reduce the height difference between the two, thereby reducing the influence of other components outside the battery cell 20 on the first fixed region 203 and the connecting portion 2133. For example, as shown in FIGS. 12 and 13, by setting the thickness of the first fixed region 203 equal to the thickness of the connecting portion 2133, the surface of the first fixed region 203 towards the interior of the battery cell 20 can be flush with the surface of the connecting portion 2133 towards the interior of the battery cell 20, and the surface of the first fixed region 203 away from the interior of the battery cell 20 can be flush with the surface of the connecting portion 2133 away from the interior of the battery cell 20.

[0166] It should be understood that the first fixed region 203, the connecting portion 2133, and the support structure 215 of the embodiments of the present application can also have other relative positional relationships. FIG. 14 shows a partial cross-sectional view of a battery cell 20 of another embodiment of the present application, for example, which can be a partial region of another possible cross-sectional view along the A-A' direction as shown in FIG. 6.

[0167] In some embodiments, the pressure relief mechanism 213, the support structure 215, and the first wall 201 are arranged in a stacking manner along the thickness direction X of the first wall 201, and are connected by the same weld joint, so as to facilitate processing. Specifically, as shown in FIG. 14, the first fixed region 203, the connecting portion 2133, and the support structure 215 can be fixed by means of a through-weld, that is, along the thickness direction X of the first wall 201, part of the first fixed region 203, part of the connecting portion 2133, and part of the support structure 215 pass through the through-weld to form the same weld joint D, which not only facilitates processing, but also can improve the structural strength and reliability of the battery cell 20.

[0168] It should be understood that the arrangement order between the first fixed region 203, the connecting portion 2133, and the support structure 215 can be set according to actual application. For example, the support structure 215 is usually located on the side of the first fixed region 203 and the connecting portion 2133 towards the interior of the battery cell 20; for another example, the first fixed region 203 can be located between the connecting portion 2133 and the support structure 215; for another example, the connecting portion 2133 can be located between the first fixed region 203 and the support structure 215, and the embodiments of the present application are not limited thereto.

[0169] In some embodiments, the first fixed region 203, the connecting portion 2133, and the support structure 215 are made of the same material, so as to be connected and fixed by the above-mentioned penetrating welding. For example, the first fixed region 203, the connecting portion 2133, and the support structure 215 are all made of steel; or, the first fixed region 203, the connecting portion 2133, and the support structure 215 are all made of copper. On the one hand, the first fixed region 203, the connecting portion 2133, and the support structure 215 have the same material, which is convenient for welding; on the other hand, the first fixed region 203, the connecting portion 2133, and the support structure 215 can be made of steel or copper to improve the structural strength of the first fixed region 203, the connecting portion 2133, and the support structure 215, and reduce the thickness of the first fixed region 203, the connecting portion 2133, and the support structure 215, thereby improving the energy density of the battery monomer 20.

[0170] It should be understood that in the above-mentioned embodiments in the present application, as shown in FIGS. 3 to 14, there is at least one welding seam between the pressure relief mechanism 213, the support structure 215, and the first wall 201, and the orthogonal projection of the at least one welding seam towards the outer surface of the support structure 215 is located in the middle region of the outer surface of the support structure 215 along the thickness direction X of the first wall 201, the outer surface of the support structure 215 being the surface of the support structure 215 away from the electrode assembly 22, so that the outer surface of the support structure 215 can cover the at least one welding seam between the pressure relief mechanism 213, the support structure 215, and the first wall 201, and the at least one welding seam does not exceed the outer surface of the support structure 215, thereby increasing the stability of the support structure 215 and improving the stability of the battery monomer 20.

[0171] In some embodiments, the orthogonal projection of the at least one welding seam towards the outer surface of the support structure 215 is symmetrically distributed with respect to the center line of the outer surface of the support structure 215 along the thickness direction X of the first wall 201, so that the at least one welding seam is more evenly distributed on the surface of the support structure 215, reducing the risk of the welding seam deviating from the outer surface of the support structure 215, and improving the structural stability and reliability. For example, as shown in FIGS. 12 and 14, in the case of one welding seam between the pressure relief mechanism 213, the support structure 215, and the first wall 201, the welding seam can be distributed close to the center line of the outer surface of the support structure 215, for example, the welding seam can be distributed along the center line of the outer surface of the support structure 215, or close to the center line of the outer surface of the support structure 215; as shown in FIG. 13, in the case of multiple welding seams, for example, two welding seams, between the pressure relief mechanism 213, the support structure 215, and the first wall 201, the multiple welding seams are symmetrically distributed with respect to the center line of the outer surface of the support structure 215, or approximately symmetrically distributed, that is, the multiple welding seams are allowed to have a small range of deviation.

[0172] In some embodiments, the side of the welding seam facing the electrode assembly 22 does not exceed the surface of the support structure 215 facing the electrode assembly 22, that is, the support structure 215 will not be welded through during the welding process, so as to prevent the welding from damaging other components inside the battery monomer 20, improve the welding efficiency and welding effect, and further improve the processing qualification rate and structural stability of the battery monomer 20.

[0173] It should be understood that the shape of the support structure 215 of the embodiments of the present application can be set according to actual application. For example, the support structure 215 is annular, and the inner ring of the support structure 215 corresponds to the pressure relief hole 202. The pressure relief mechanism 213 is used to cover the pressure relief hole 202, and therefore, the connecting portion 2133 of the pressure relief mechanism 213 and the first fixed region 203 of the first wall 201 are generally close to the pressure relief hole 202. The support structure 215 is annular, and the inner ring corresponds to the pressure relief hole 202, which not only facilitates the relative fixation of the support structure 215, the first fixed region 203 and the connecting portion 2133, but also can reduce the influence of the support structure 215 on the pressure relief hole 202. When the battery monomer 20 occurs thermal runaway, the pressure relief mechanism 213 can be damaged in time through the pressure relief hole 202, so as to actuate the pressure relief mechanism 213 in time, and improve the reliability of the battery monomer 20.

[0174] In some embodiments, the support structure 215 can be a circular ring structure or a square ring structure, or the support structure 215 can also be other annular structures. For example, as shown in FIGS. 3 to 14, taking the pressure relief hole 202 as a waist circle as an example, the support structure 215 corresponding thereto can also be a waist circle annular structure, and the embodiments of the present application are not limited thereto.

[0175] In some embodiments, the surface of the support structure 215 facing the first fixed region 203 and the connecting portion 2133 is a plane before welding. Considering that the surface of the first fixed region 203 facing the support structure 215 and the surface of the connecting portion 2133 facing the support structure 215 are generally planes, and the surface of the support structure 215 facing the first fixed region 203 and the connecting portion 2133 is used to be attached to the surface of the first fixed region 203 and / or the surface of the connecting portion 2133, therefore, the surface of the support structure 215 is set as a plane, so as to facilitate the close attachment of the support structure 215 to the surface of the first fixed region 203 and / or the surface of the connecting portion 2133, reduce the gap, and further improve the welding effect and the structural strength after welding of the support structure 215, the first fixed region 203 and the connecting portion 2133, and reduce the welding burst points caused by the excessive gap between the support structure 215 and the first fixed region 203, or also can reduce the welding burst points caused by the excessive gap between the support structure 215 and the connecting portion 2133.

[0176] The pressure relief mechanism 213 of the embodiments of the present application will be described below in conjunction with the drawings.

[0177] FIG. 15 shows another partial cross-sectional schematic view of the battery cell 20 according to embodiments of the present application, for example, FIG. 15 can be a zoomed-in view of region E shown in FIG. 14. Hereinafter, the pressure relief mechanism 213 as shown in FIGS. 14 and 15 is mainly taken as an example for description, but the relevant description is also applicable to the pressure relief mechanism 213 of other embodiments of the present application, for example, can be applicable to the pressure relief mechanism 213 as shown in FIGS. 3-9 and FIGS. 12-13, and for the sake of brevity, will not be described here.

[0178] In some embodiments, the thickness of the weak portion 2132 according to embodiments of the present application can be set according to actual application. For example, taking the notch as the weak portion 2132, the minimum thickness T0 of the notch is in the range of [8 μm, 100 μm]. The minimum thickness T0 of the notch is greater than or equal to 8 μm, so as to improve the structural strength of the pressure relief mechanism 213 in the case of normal use of the battery cell 20, and reduce the risk of premature cracking of the pressure relief mechanism 213; the minimum thickness T0 of the notch is less than or equal to 100 μm, so that the notch can be damaged in time when the battery cell 20 is in thermal runaway, so as to quickly release the pressure and temperature inside the battery cell 20, reduce the risk of thermal diffusion, and improve the reliability of the battery device 10.

[0179] In some embodiments, the minimum thickness T0 of the notch can be equal to any of the following values or between any two of the following values: 8 μm, 10 μm, 13 μm, 15 μm, 18 μm, 20 μm, 23 μm, 25 μm, 28 μm, 30 μm, 33 μm, 35 μm, 38 μm, 40 μm, 43 μm, 45 μm, 48 μm, 50 μm, 53 μm, 55 μm, 58 μm, 60 μm, 63 μm, 65 μm, 68 μm, 70 μm, 73 μm, 75 μm, 78 μm, 80 μm, 83 μm, 85 μm, 88 μm, 90 μm, 93 μm, 95 μm, 98 μm, and 100 μm.

[0180] It should be understood that the specific shape of the pressure relief mechanism 213 according to embodiments of the present application can be set according to actual application. In some embodiments, the body portion 2131 can be an arch-shaped structure, so as to facilitate processing, and during use of the battery cell 20, the battery cell 20 will swell during charging and discharging, for example, the battery cell 20 will repeatedly swell and deform in the direction parallel to the first wall 201 and the direction perpendicular to the first wall 201, the arch-shaped body portion 2131 can effectively absorb the deformation amount, improve the structural strength and fatigue resistance of the pressure relief mechanism 213, and further improve the service life of the pressure relief mechanism 213.

[0181] In some embodiments, the position of the arched body part 2131 can be related to the electrode assembly 22 in the shell. Specifically, the electrode assembly 22 includes at least two layers of electrode sheets; the at least two layers of electrode sheets are stacked, the stacking direction of the at least two layers of electrode sheets is the first direction Y; or, the at least two layers of electrode sheets are wound, the at least two layers of electrode sheets each include a planar section at the middle of the electrode assembly 22 and curved sections at both ends of the electrode assembly 22, and the stacking direction of the at least two layers of electrode sheets at the planar section is the first direction Y. The cross section of the body part 2131 in at least one plane perpendicular to the first direction Y is arched, for example, in the embodiments of the present application, the first direction Y is taken as the thickness direction Y of the battery monomer 20. By setting the cross section of the body part 2131 in at least one plane perpendicular to the first direction Y to be arched, the deformation of the electrode assembly 22 can be effectively absorbed, the deformation capacity of the pressure relief mechanism 213 is improved, and the service life of the pressure relief mechanism 213 is further improved.

[0182] Further, considering that the deformation amount of the electrode assembly 22 along the first direction Y is usually large during the use of the battery monomer 20, whether it is a wound electrode assembly 22 or a stacked electrode assembly 22, the cross section of the body part 2131 in at least one plane parallel to the first direction Y can also be arched, for example, the at least one plane can be perpendicular to the height direction Z of the battery monomer 20, and the cross section of the body part 2131 is arched as shown in FIGS. 14 and 15, which can effectively absorb the deformation of the electrode assembly 22, further improve the deformation capacity of the pressure relief mechanism 213, and further improve the service life of the pressure relief mechanism 213 and the battery monomer 20.

[0183] It should be understood that the protrusion height of the body part 2131 of the embodiments of the present application can be set according to actual application. For example, the protrusion height H of the body part 2131 relative to the weak part 2132 is in the range of [0.5mm, 4mm]. By setting the protrusion height H of the body part 2131 relative to the weak part 2132 to be greater than or equal to 0.5mm, the body part 2131 effectively absorbs the deformation amount, and the structural stability of the body part 2131 is improved; by setting the protrusion height H of the body part 2131 relative to the weak part 2132 to be less than or equal to 4mm, the space occupied by the body part 2131 can be limited, and the space occupied by the pressure relief mechanism 213 is further limited, the space utilization rate of the battery monomer 20 is improved, and the energy density of the battery monomer 20 is further improved.

[0184] In some embodiments, the protrusion height H of the body part 2131 relative to the weak part 2132 can be equal to any of the following values or between any two of the following values: 0.5mm, 0.8mm, 1mm, 1.3mm, 1.5mm, 1.8mm, 2mm, 2.3mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.8mm and 4mm.

[0185] It should be understood that the protruding direction of the body portion 2131 of the embodiment of the application can be set according to actual application. For example, as shown in FIG. 14 and FIG. 15, the connecting portion 2133 includes a fixed area 2135 and a transition area 2136, the fixed area 2135 is used to connect with the first wall 201, the transition area 2136 is used to connect the fixed area 2135 and the weak portion 2132, the fixed area 2135 is arranged parallel to the first wall 201, and the transition area 2136 and the body portion 2131 are both protruded towards the direction away from the electrode assembly 22 relative to the weak portion 2132.

[0186] When the battery cell 20 is working normally, the internal pressure or temperature of the battery cell 20 is low. The following is described by taking the internal pressure as an example. The internal pressure of the battery cell 20 continuously acts on the pressure relief mechanism 213, so that the body portion 2131, the weak portion 2132 and the transition area 2136 move upward or have a tendency to move upward, and the body portion 2131 has a tendency to shrink to the center with the contour circumference reduced.

[0187] Due to the inclination of the transition area 2136 towards the inside of the battery cell 20, the position of the weak portion 2132 is closer to the inside of the battery cell 20 than the fixed area 2135, that is, the position of the weak portion 2132 is closer to the inside of the battery cell 20 than the fixed position of the pressure relief mechanism 213 and the cover plate 212. And due to the constraint of one end of the transition area 2136 by the fixed area 2135, under the action of the internal pressure, the end of the transition area 2136 extending to the inside of the battery cell 20 will extrude the weak portion 2132 towards the direction of the weak portion 2132, thereby inhibiting the cracking of the weak portion 2132 and reducing the risk of creep failure of the pressure relief mechanism 213 when the battery cell 20 is working normally, effectively prolonging the service life of the pressure relief mechanism 213. On the other hand, the outwardly protruding body portion 2131 can support the transition area 2136 and the weak portion 2132, and can effectively extrude the weak portion 2132.

[0188] When the internal pressure or temperature of the battery cell 20 continues to increase until it is greater than or equal to a predetermined value, the battery cell 20 can be about to have thermal runaway, and the transition zone 2136 can be flipped from the state of extending toward the inside of the battery cell 20 to the state of extending away from the inside of the battery cell 20. Specifically, when the internal pressure or temperature of the battery cell 20 increases to reach or exceed the predetermined value, the transition zone 2136, the weakened portion 2132, and the body portion 2131 as a whole continue to move upward, wherein the transition zone 2136 deforms greatly and is flipped from the state of extending toward the inside of the battery cell 20 to the state of extending away from the inside of the battery cell 20. More specifically, the part of the transition zone 2136 adjacent to the weakened portion 2132 changes to the state of extending away from the inside of the battery cell 20, while the part adjacent to the fixed zone 2135 is constrained by the fixed zone 2135 and moves relatively less. After the transition zone 2136 is flipped, the transition zone 2136 substantially as a whole changes to the state of extending away from the inside of the battery cell 20, and the transition zone 2136 changes from the state of pressing the weakened portion 2132 to the state of stretching the weakened portion 2132, promoting the weakened portion 2132 to crack and helping to achieve rapid pressure relief. On the other hand, the body portion 2131 moves upward under the action of the pressure and also stretches the weakened portion 2132, promoting the weakened portion 2132 to crack and helping to achieve rapid pressure relief.

[0189] It should be understood that the fixed zone 2135 of the embodiment of the present application is used to be connected with the first wall 201, for example, the first wall 201 can include a first fixed area 203 used to be fixedly connected with the fixed zone 2135 to achieve the fixed connection between the pressure relief mechanism 213 and the first wall 201. The fixed zone 2135 of the embodiment of the present application is arranged in parallel with respect to the first wall 201, for example, the fixed zone 2135 can be a plate-shaped structure, that is, the fixed zone 2135 is relatively flat, rather than a concave-convex or inclined area, so as to be fixedly connected with the first fixed area 203 of the first wall 201 which is also relatively flat.

[0190] In the embodiment of the present application, for the case that the body portion 2131 and the transition zone 2136 both protrude away from the electrode assembly 22, the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 does not exceed the surface of the first wall 201 away from the inside of the battery cell 20, so as to reduce the case that the pressure relief mechanism 213 is worn by contacting external components and improve the service life of the pressure relief mechanism 213. As shown in FIGS. 14 and 15, the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 does not exceed the surface of the first wall 201 away from the inside of the battery cell 20 includes that on the side away from the inside of the battery cell 20, the outermost surface of the first wall 201 and the outermost surface of the pressure relief mechanism 213 are flush, or the outermost surface of the first wall 201 exceeds the outermost surface of the pressure relief mechanism 213.

[0191] It should be understood that the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 can be no more than the surface of the first wall 201 away from the inside of the battery cell 20 in various ways. For example, the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 can be no more than the surface of the first wall 201 away from the inside of the battery cell 20 by providing a groove on the pressure relief mechanism 213 and / or the first wall 201.

[0192] In some embodiments, the pressure relief mechanism 213 includes a first groove 2134 recessed toward the inside of the battery cell 20, a bottom wall of the first groove 2134 includes a weak portion 2132, a part of a side wall of the first groove 2134 is a transition zone 2136, and another part of the side wall of the first groove 2134 is at least a part of the body portion 2131. The first groove 2134 is configured to allow the body portion 2131 and the transition zone 2136 to protrude toward the direction away from the electrode assembly 22, and the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 is no more than the surface of the first wall 201 away from the inside of the battery cell 20. In addition, the pressure relief mechanism 213 is provided with the first groove 2134 recessed toward the inside of the battery cell 20, which can be used to absorb the expansion in the direction parallel to the surface of the first wall 201, and improve the structural strength of the pressure relief mechanism 213.

[0193] In some embodiments, the first wall 201 is provided with a second groove 204 recessed toward the inside of the battery cell 20, and the pressure relief mechanism 213 is located on the bottom wall of the second groove 204. FIG. 16 shows a partial cross-sectional view of the first wall 201 of an embodiment of the present application. For example, FIG. 16 can be a partial cross-sectional view of the first wall 201 in FIG. 14. In the embodiments of the present application, as shown in FIGS. 14-16, the first wall 201 is provided with the second groove 204. By setting the depth of the second groove 204, at least a part of the pressure relief mechanism 213 can be located in the second groove 204, for example, the protruding body portion 2131 of the pressure relief mechanism 213 can be located in the second groove 204, so that the surface of the pressure relief mechanism 213 away from the inside of the battery cell 20 is no more than the surface of the first wall 201 away from the inside of the battery cell 20, thereby protecting the pressure relief mechanism 213 and improving the service life of the pressure relief mechanism 213.

[0194] In some embodiments, the body portion 2131 and the transition portion 2136 are both convex towards the direction away from the electrode assembly 22, and the weak portion 2132 of the pressure relief mechanism 213 is closer to the electrode assembly 22 than other regions of the pressure relief mechanism 213. In the thickness direction X of the pressure relief mechanism 213 and from the pressure relief mechanism 213 to the electrode assembly 22, the surface of the weak portion 2132 towards the electrode assembly 22 does not exceed the surface of the support structure 215 towards the electrode assembly 22, i.e. the surface of the support structure 215 towards the electrode assembly 22 is closer to the electrode assembly 22 than the surface of the weak portion 2132 towards the electrode assembly 22. In this way, the weak portion 2132 of the pressure relief mechanism 213 can be protected by the support structure 215, the mutual influence between the pressure relief mechanism 213 and the electrode assembly 22 can be reduced, and the support structure 215 and the weak portion 2132 of the pressure relief mechanism 213 that is convex towards the inside of the battery monomer 20 can share the space in the thickness direction X of the pressure relief mechanism 213, saving the occupied space and improving the energy density of the battery monomer 20.

[0195] In some embodiments, the body portion 2131 can also be convex towards the direction of the electrode assembly 22. FIG. 17 shows a partial cross-sectional view of a battery monomer 20 according to another embodiment of the present application. The direction of the cross-sectional view shown in FIG. 17 is consistent with that shown in FIG. 14, i.e. FIG. 17 shows a partial cross-sectional view of a battery monomer 20 different from that shown in FIG. 14.

[0196] As shown in FIG. 17, the connecting portion 2133 includes a fixed portion 2135 and a transition portion 2136, the fixed portion 2135 is used to connect with the first wall 201, the transition portion 2136 is used to connect the fixed portion 2135 and the weak portion 2132, the fixed portion 2135 is arranged parallel to the first wall 201, and the transition portion 2136 is convex towards the direction close to the electrode assembly 22 relative to the fixed portion 2135; the body portion 2131 is convex towards the direction close to the electrode assembly 22 relative to the fixed portion 2135, i.e. the transition portion 2136, the weak portion 2132 and the body portion 2131 are all convex towards the direction close to the electrode assembly 22.

[0197] When the battery monomer 20 is working normally, the internal pressure or temperature of the battery monomer 20 is low. The following is illustrated by taking the internal pressure as an example. The internal pressure of the battery monomer 20 continuously acts on the pressure relief mechanism 213, causing the transition portion 2136, the weak portion 2132 and the body portion 2131 to move upwards or have a tendency to move upwards, and the overall profile circumference of the transition portion 2136, the weak portion 2132 and the body portion 2131 is reduced and shrinks towards the center.

[0198] As shown in FIG. 17, due to the inclination of the transition region 2136 towards the inside of the battery cell 20, the position of the weak portion 2132 is closer to the inside of the battery cell 20 than the position of the fixed region 2135, that is, the position of the weak portion 2132 is closer to the inside of the battery cell 20 than the position of the fixing of the pressure relief mechanism 213 and the cover plate 212. Moreover, due to the constraint of the fixed region 2135 on one end of the transition region 2136, the end of the transition region 2136 extending towards the inside of the battery cell 20 presses the weak portion 2132 in the direction of the weak portion 2132, thereby inhibiting the cracking of the weak portion 2132 and reducing the risk of creep failure of the pressure relief mechanism 213 during normal operation of the battery cell 20, effectively prolonging the service life of the pressure relief mechanism. Similarly, the body portion 2131 moves upward under the action of gas pressure, and the end of the body portion 2131 close to the weak portion 2132 presses the weak portion 2132 in the direction of the weak portion 2132, which can also inhibit the cracking of the weak portion 2132 and reduce the risk of creep failure of the pressure relief mechanism 213 during normal operation of the battery cell 20, effectively prolonging the service life of the pressure relief mechanism 213.

[0199] When the internal gas pressure or temperature of the battery cell 20 continues to rise and reaches or exceeds a predetermined value, the battery cell 20 may be about to experience thermal runaway, and the transition region 2136, the weak portion 2132 and the body portion 2131 as a whole continue to move upward, wherein the body portion 2131 deforms greatly and may be flipped from a downward protruding shape to an upward protruding shape. At this time, the middle region of the body portion 2131 moves above the weak portion 2132, and the transition region 2136 is constrained by the fixed region 2135 and moves little. After the body portion 2131 is flipped, the body portion 2131 as a whole moves above the weak portion 2132, and the body portion 2131 changes from the state of pressing the weak portion 2132 to the state of stretching the weak portion 2132, thereby promoting the cracking of the weak portion 2132 and facilitating rapid pressure relief.

[0200] In some embodiments, unlike shown in FIG. 17, the transition region 2136 of the embodiments of the present application can also not be protruding. For example, the fixed region 2135 is arranged parallel to the first wall 201, the transition region 2136 is flush with the fixed region 2135, and the body portion 2131 protrudes towards the direction close to the electrode assembly 22 relative to the fixed region 2135, that is, the body portion 2131 protrudes towards the direction close to the electrode assembly 22 relative to the fixed region 2135, and the weak portion 2132 is not protruding with the transition region 2136.

[0201] When the battery cell 20 is working normally, the internal pressure or temperature of the battery cell 20 is low. The following is described by taking the internal pressure as an example. The internal pressure of the battery cell 20 continuously acts on the pressure relief mechanism 213, causing the body part 2131 to move upward or have a tendency to move upward, and the body part 2131 to shrink toward the center and reduce the profile circumference. The body part 2131 moves upward under the action of the internal pressure, and the end of the body part 2131 close to the weak part 2132 presses the weak part 2132 toward the weak part 2132, which can inhibit the cracking of the weak part 2132 and reduce the risk of creep failure of the pressure relief mechanism 213 when the battery cell 20 is working normally, effectively prolonging the service life of the pressure relief mechanism 213.

[0202] When the internal pressure or temperature of the battery cell 20 continuously rises and reaches or exceeds a predetermined value, the battery cell 20 may be about to have thermal runaway, and the body part 2131 as a whole continues to move upward and may be deformed greatly, and then flips from the downward convex shape to the upward convex shape. At this time, the middle region of the body part 2131 moves above the weak part 2132, and the transition region 2136 moves little due to the constraint of the fixed region 2135. After the body part 2131 is flipped, the body part 2131 as a whole moves above the weak part 2132, and the body part 2131 changes from the state of pressing the weak part 2132 to the state of stretching the weak part 2132, thereby promoting the cracking of the weak part 2132 and helping to achieve rapid pressure relief.

[0203] In some embodiments, for the case that the body part 2131 protrudes toward the direction close to the electrode assembly 22, the body part 2131 is closer to the electrode assembly 22 than other parts of the pressure relief mechanism 213. In the thickness direction X of the pressure relief mechanism 213 and from the pressure relief mechanism 213 to the electrode assembly 22, the surface of the body part 2131 toward the electrode assembly 22 does not exceed the surface of the support structure 215 toward the electrode assembly 22, i.e., the surface of the support structure 215 toward the electrode assembly 22 is closer to the electrode assembly 22 than the surface of the body part 2131 toward the electrode assembly 22. This can protect the body part 2131 of the pressure relief mechanism 213, reduce the mutual influence between the pressure relief mechanism 213 and the electrode assembly 22, and also allow the support structure 215 and the body part 2131 protruding into the battery cell 20 to share the space in the thickness direction X of the pressure relief mechanism 213, saving the occupied space and improving the energy density of the battery cell 20.

[0204] It should be understood that in the above embodiments, if the transition region 2136 is convex relative to the fixed region 2135 towards the direction close to the electrode assembly 22, the inclination angle thereof can be set according to actual application. For example, as shown in FIGS. 14-17, the transition region 2136 is convex relative to the fixed region 2135 towards the direction close to the electrode assembly 22, and the inclination angle θ of the transition region 2136 relative to the fixed region 2135 is in the range of [40°, 75°]. Setting the inclination angle θ of the transition region 2136 relative to the fixed region 2135 to be greater than or equal to 40° can control the bending degree between the transition region 2136 and the fixed region 2135 not to be too large, reduce the stress concentration in the region between the transition region 2136 and the fixed region 2135, and improve the structural strength; setting the inclination angle θ of the transition region 2136 relative to the fixed region 2135 to be less than or equal to 75° can control the bending degree between the transition region 2136 and the fixed region 2135 not to be too small, and in the case where the body portion 2131 is convex towards the direction away from the electrode assembly 22 as shown in FIGS. 14-16, and in the case where the body portion 2131 is convex towards the direction close to the electrode assembly 22 as shown in FIG. 17, the risk of creep failure of the pressure relief mechanism 213 during normal operation of the battery monomer 20 can be reduced, the service life of the pressure relief mechanism 213 can be effectively prolonged, and the cracking of the weak portion 2132 can be promoted to help achieve rapid pressure relief when the battery monomer 20 is in thermal runaway.

[0205] In some embodiments, the inclination angle θ of the transition region 2136 relative to the fixed region 2135 can be equal to any of the following values or between any two of the following values: 40°, 45°, 50°, 55°, 60°, 65°, 70°, and 75°.

[0206] In the embodiments of the present application, the battery monomer 20 further comprises a protective sheet 217 located on the side of the pressure relief mechanism 213 away from the electrode assembly 22 to protect the pressure relief mechanism 213, reduce damage to the pressure relief mechanism 213 from external components of the battery monomer 20, and improve the service life of the pressure relief mechanism 213.

[0207] FIGS. 18 and 19 respectively show another two possible partial cross-sectional views of the battery monomer 20 according to the embodiments of the present application, for example, both of the FIGS. 18 and 19 take the welding mode as shown in FIG. 12 as an example, and respectively show possible structures of the protective sheet 217 according to the embodiments of the present application, but the relevant description is also applicable to other embodiments of the present application, and for the sake of brevity, will not be repeated here.

[0208] In some embodiments, as shown in FIG. 18, the side of the connecting portion 2133 away from the electrode assembly 22 is provided with a stepped structure 2137, the protection sheet 217 is fixed to the bottom wall of the stepped structure 2137, and the side of the body portion 2131 away from the electrode assembly 22 does not exceed the bottom wall of the stepped structure 2137. By arranging the stepped structure 2137 to accommodate at least part of the area of the protection sheet 217, the height of the surface of the protection sheet 217 facing the outside of the battery monomer 20 beyond the surface of the first wall 201 can be reduced. For example, the depth of the stepped structure 2137 can be arranged such that the surface of the protection sheet 217 facing the outside of the battery monomer 20 does not exceed the surface of the first wall 201 facing the outside of the battery monomer 20, so that the outer surface of the battery monomer 20 is relatively smooth, the local protrusion is reduced, the arrangement of multiple battery monomers 20 in the battery device 10 is facilitated, the mutual influence of the multiple battery monomers 20 is reduced, the space utilization rate inside the battery device 10 is improved, and the energy density of the battery device 10 is further improved.

[0209] In some embodiments, as shown in FIG. 19, the protection sheet 217 is fixed to the side of the first wall 201 away from the electrode assembly 22, and the protection sheet 217 covers the weld between the pressure relief mechanism 213 and the first wall 201. By covering the pressure relief mechanism 213 with the protection sheet 217, the pressure relief mechanism 213 can be protected. Further, the protection sheet 217 can also be used to cover the weld between the pressure relief mechanism 213 and the first wall 201 to protect the weld and improve the stability and reliability of the weld between the pressure relief mechanism 213 and the first wall 201. For example, there can be at least one weld between the pressure relief mechanism 213 and the first wall 201, and the protection sheet 217 can be used to cover all of the at least one weld to protect the at least one weld, but the embodiments of the present application are not limited thereto.

[0210] FIG. 20 shows another partial cross-sectional view of the battery monomer 20 according to an embodiment of the present application. For example, FIG. 20 can be a partial area of the cross-sectional view along the direction of F-F’ shown in FIG. 6, which can be the area G shown in FIG. 6.

[0211] As shown in FIG. 20, the battery monomer 20 according to an embodiment of the present application further comprises a protection member 216 fixed to the side of the first wall 201 facing the electrode assembly 22, the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the electrode assembly 22 protrude from the surface of the first wall 201 facing the electrode assembly 22, and the surface 2161 of the protection member 216 facing the electrode assembly 22 protrudes from the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the electrode assembly 22.

[0212] In the embodiments of the present application, the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the inside of the battery cell 20 are all protruding from the surface of the first wall 201 facing the inside of the battery cell 20, so as to reduce the part of the side of the pressure relief mechanism 213 facing the outside of the battery cell 20 protruding from the first wall 201, reduce the external space occupied by the pressure relief mechanism 213, and further reduce the mutual influence between the pressure relief mechanism 213 and other components outside. It should be understood that the support structure 215 and the pressure relief mechanism 213 of the embodiments of the present application can only exist in some areas to meet the surface facing the battery cell 20 protruding from the first wall 201, so as to flexibly set the structure and position of the pressure relief mechanism 213 and the support structure 215.

[0213] Further, the side of the first wall 201 facing the inside of the battery cell 20 is provided with a protection piece 216, and the surface 2161 of the protection piece 216 facing the inside of the battery cell 20 protrudes from the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the inside of the battery cell 20, i.e. along the thickness direction X of the first wall 201, and at least part of the surface 2161 of the protection piece 216 facing the inside of the battery cell 20 can protrude from the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the inside of the battery cell 20. In this way, the influence of the components inside the battery cell 20 on the support structure 215 and the pressure relief mechanism 213 can be reduced, and the reliability of the pressure relief mechanism 213 and the battery cell 20 can be improved.

[0214] In some embodiments, as shown in FIGS. 3-7 and 12-20, the first wall 201 is a side wall of the shell 211 adjacent to the opening 2111, i.e. the pressure relief mechanism 213 is arranged on the first wall 201. On the one hand, since the area of the cover plate 212 is limited, arranging the pressure relief mechanism 213 on the shell 211 can save the space of the cover plate 212 and facilitate processing. On the other hand, when the electrode assembly 22 enters the shell 211 from the opening 2111 of the shell 211, since the surface 2161 of the protection piece 216 facing the inside of the battery cell 20 protrudes from the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the inside of the battery cell 20, the electrode assembly 22 can enter the shell 211 along the surface of the protection piece 216 facing the inside of the battery cell 20, reducing the interference of the electrode assembly 22 with the pressure relief mechanism 213 and the support structure 215 during assembly, protecting the pressure relief mechanism 213 and the support structure 215, and further improving the processing yield of the battery cell 20, and also improving the reliability and service life of the pressure relief mechanism 213 and the battery cell 20.

[0215] In some embodiments, an end of the protective member 216 facing the opening 2111 is provided with a chamfer 2165 at an intersection of a surface 2161 of the protective member 216 facing the inside of the battery cell 20, so as to facilitate the entry of the internal electrode assembly 22, reduce the obstruction of the electrode assembly 22 by the protective member 216, and improve the installation efficiency.

[0216] It should be understood that the shape of the chamfer 2165 of the embodiments of the present application can be set according to actual application. FIGS. 21 and 22 respectively show a partial cross-sectional view of the protective member 216 of the embodiments of the present application, for example, FIGS. 21 and 22 can be other possible implementations of the area of the protective member 216 close to the chamfer 2165 in the cross-sectional view shown in FIG. 20, and the cross-section shown in FIGS. 21 and 22 can be a partial cross-sectional view in the F-F' direction shown in FIG. 6.

[0217] In some embodiments, as shown in FIG. 20, the chamfer 2165 can be an inclined plane, i.e., an inclined plane is provided at the intersection of the surface 2161 of the protective member 216 facing the inside of the battery cell 20 and an end of the protective member 216 facing the opening 2111 as the chamfer 2165.

[0218] In some embodiments, as shown in FIG. 21, the chamfer 2165 can also be a rounded corner, i.e., the surface 2161 of the protective member 216 facing the inside of the battery cell 20 and an end of the protective member 216 facing the opening 2111 are connected by a rounded corner to form the chamfer 2165.

[0219] In some embodiments, considering that the thickness of the protective member 216 is generally thin, the chamfer 2165 can occupy at least part of the area of an end of the protective member 216 facing the opening 2111. For example, as shown in FIGS. 20 and 21, a partial area of an end of the protective member 216 facing the opening 2111 is used to form the chamfer 2165; or, as shown in FIG. 22, the entire area of an end of the protective member 216 facing the opening 2111 can be used to form the chamfer 2165, so that the area where the chamfer 2165 is located is larger, facilitating the entry of the electrode assembly 22 into the inside of the shell 211, and improving the installation efficiency, but the embodiments of the present application are not limited thereto.

[0220] In some embodiments, the surfaces 2161 of the protective member 216 facing the inside of the battery cell 20 are flush with each other, i.e., the surfaces 2161 of the protective member 216 facing the inside of the battery cell 20 are relatively flat, so that the electrode assembly 22 can quickly enter the inside of the shell 211 along the surfaces 2161, which can not only reduce the damage to the electrode assembly 22, but also speed up the processing and assembly efficiency of the battery cell 20.

[0221] In some embodiments, the protector 216 is arranged around the support structure 215 and the pressure relief mechanism 213, instead of being arranged only in the middle region of the support structure 215 and the pressure relief mechanism 213, which can reduce the processing and installation difficulty of the protector 216 on the one hand, and on the other hand, considering the process of assembling the internal components of the battery monomer 20, such as the process of assembling the electrode assembly 22, the process of entering the inside of the battery monomer 20 from the opening 2111 of the shell 211, the protector 216 arranged around the pressure relief mechanism 213 can better protect the pressure relief mechanism 213 and / or the support structure 215.

[0222] It should be understood that the arrangement of the protector 216 around the pressure relief mechanism 213 can include that the protector 216 is arranged around the periphery of the pressure relief mechanism 213, or the protector 216 can be arranged around the periphery of a local region of the pressure relief mechanism 213.

[0223] It should be understood that the protector 216 of the embodiments of the present application can be implemented in various ways. For example, the protector 216 of the embodiments of the present application can be an integral structure, or the protector 216 can include a plurality of separately arranged parts to be flexibly applicable to various application scenarios. FIG. 23 shows a possible side view structural schematic diagram of the protector 216 of the embodiments of the present application, for example, which can be a side view of the protector 216 included in the battery monomer 20 shown in FIGS. 3 to 7.

[0224] In some embodiments, as shown in FIG. 23, the protector 216 includes a first part 2163 and a second part 2164 arranged at intervals, and the pressure relief mechanism 213 and the support structure 215 are located between the first part 2163 and the second part 2164.

[0225] The protector 216 includes a first part 2163 and a second part 2164 arranged at intervals, and the pressure relief mechanism 213 is located between the first part 2163 and the second part 2164. The arrangement of the protector 216 including the first part 2163 and the second part 2164 arranged separately can reduce the processing difficulty of the protector 216, especially in the case that the area of the first wall 201 is limited, there can be a region with a size that is too small around the pressure relief mechanism 213, for example, the size along the width direction Y of the first wall 201 can be small, and then the processing difficulty of the protector 216 can be reduced by not arranging the protector 216 in this region, and the pressure relief mechanism 213 located between the first part 2163 and the second part 2164 can still effectively protect the pressure relief mechanism 213.

[0226] Further, the first part 2163 and the second part 2164 are distributed along the direction Z perpendicular to the end face of the opening 2111, that is, along the direction in which the electrode assembly 22 enters the shell 211, so that the electrode assembly 22 contacts the protective member 216 during the assembly process, for example, can first contact the first part 2163, to protect the pressure relief mechanism 213 as much as possible.

[0227] In some embodiments, the protective member 216 can also include more than two sub-structures, which are arranged around the pressure relief mechanism 213 to protect the pressure relief mechanism 213, so that the protective member 216 is arranged more flexibly.

[0228] In some embodiments, the protective member 216 can also be a one-piece structure. FIG. 24 shows another possible side view structure of the protective member 216 of the present application, for example, which can be another structure of the protective member 216 included in the battery monomer 20 shown in FIGS. 3 to 7. As shown in FIG. 24, the protective member 216 is provided with a relief opening 2162 for avoiding the pressure relief mechanism 213 and the support structure 215, which is simple to process, and by arranging the relief opening 2162, the pressure relief mechanism 213 can be avoided, reducing the obstruction to the pressure relief mechanism 213, so that the pressure relief mechanism 213 can be actuated in time when the battery monomer 20 is in thermal runaway.

[0229] In some embodiments, as shown in FIG. 24, the one-piece protective member 216 can also be arranged in other structures, for example, the protective member 216 is provided with a groove 2166 with an opening facing the pressure relief mechanism 213, the groove 2166 is used to accommodate the pressure relief mechanism 213 and the support structure 215, and the bottom of the groove 2166 is provided with a thinning area 2167 corresponding to the pressure relief mechanism 213. The thickness of the thinning area 2167 is less than the thickness of other areas of the bottom of the groove 2166. On the one hand, the internal space of the groove 2166 can be used to avoid the pressure relief mechanism 213 and the support structure 215, and the thinning area 2167 provided on the bottom wall of the groove 2166 can be used to be damaged in time when the battery monomer 20 is in thermal runaway, to reduce the influence of the bottom wall of the groove 2166 on the pressure relief mechanism 213, so that the pressure relief mechanism 213 can be damaged in time and the pressure inside the battery monomer 20 can be released in time. In addition, the surface of the protective member 216 facing the inside of the battery monomer 20 is a continuous plane without discontinuous areas, so that the electrode assembly 22 can enter the shell 211 more smoothly and continuously, improving the installation efficiency.

[0230] FIG. 25 and FIG. 26 respectively show a cross-sectional view of the protection member 216 of the embodiments of the present application, for example, the cross-sections shown in FIG. 25 and FIG. 26 are perpendicular to the thickness direction Y of the battery cell 20, and FIG. 25 and FIG. 26 can both be cross-sectional views of the possible structure of the protection member 216 along the F-F’ direction shown in FIG. 6. As shown in FIG. 25, the thinned area 2167 of the bottom wall of the groove 2166 can be a groove structure, and the area of the thinned area 2167 covers at least the annular weak portion 2132 of the pressure relief mechanism 213 to reduce the impact on the actuation of the pressure relief mechanism 213.

[0231] In some embodiments, as shown in FIG. 26, the thinned area 2167 of the bottom wall of the groove 2166 can also be an annular structure, so that the thinned area 2167 corresponds to the annular weak portion 2132 of the pressure relief mechanism 213 to reduce the impact on the actuation of the pressure relief mechanism 213.

[0232] It should be understood that the size of the protection member 216 of the embodiments of the present application can be set according to actual application. For example, in the case that the protection member 216 is provided with the avoiding opening 2162 or the groove 2166, the size of the avoiding opening 2162 or the groove 2166 in each direction is generally greater than or equal to the size of the pressure relief mechanism 213 to reduce the blockage of the avoiding opening 2162 or the groove 2166 to the pressure relief mechanism 213, so that the pressure relief mechanism 213 can be actuated in time when the battery cell 20 is in thermal runaway. For another example, in each direction parallel to the first wall 201, the size of the protection member 216 is generally less than or equal to the size of the first wall 201 to reduce the impact of the protection member 216 on the bending area of the shell 211, and also to reduce the impact on the connection between the shell 211 and the cover plate 212, thereby improving the reliability of the shell 211. For another example, in the direction Z perpendicular to the end surface of the opening 2111 of the shell 211, the size of the protection member 216 is generally close to the size of the first wall 201 to maximize the protection of the electrode assembly 22 from entering the shell 211.

[0233] It should be understood that the material of the protection member 216 of the embodiments of the present application can be set according to actual application. For example, the protection member 216 is generally an insulating material. For another example, the material of the protection member 216 includes plastic to reduce cost and facilitate processing.

[0234] It should be understood that the fixing mode of the protection member 216 of the embodiments of the present application can be set according to actual application. For example, the protection member 216 is fixed to the first wall 201 by an adhesive, which is simple to operate and easy to implement, and has stable structure to reduce the risk of mutual misalignment between the protection member 216 and the first wall 201, or even the falling of the protection member 216.

[0235] According to some embodiments of the present application, the present application also provides a battery device 10 comprising the battery cell 20 of any one of the above-mentioned solutions.

[0236] According to some embodiments of the present application, the present application further provides a battery device 10, which is used to provide electric energy for an electric device.

[0237] The electric device can be any of the devices or systems mentioned above.

[0238] According to some embodiments of the present application, the present application provides a battery cell 20, which comprises: a shell 211 having a first wall 201 provided with a pressure relief hole 202; an electrode assembly 22 accommodated in the shell 211; a pressure relief mechanism 213 covering the pressure relief hole 202; a support structure 215 fixed to a side of the first wall 201 facing the electrode assembly 22, the pressure relief mechanism 213 being located on a side of the support structure 215 facing away from the electrode assembly 22, and the pressure relief mechanism 213 being welded to at least one of the support structure 215 and the first wall 201.

[0239] The support structure 215 and the first wall 201 are fixed by welding or by adhesion. The materials of the pressure relief mechanism 213, the support structure 215 and the first wall 201 all comprise steel.

[0240] The base material of the pressure relief mechanism 213 is iron; the pressure relief mechanism 213 comprises a weak portion 2132 configured to be broken to release pressure when the pressure inside the shell 211 reaches a threshold value, a body portion 2131 located in an area surrounded by the weak portion 2132, and a connecting portion 2133 located outside the weak portion 2132 and used to connect the first wall 201; the body portion 2131 is a protruding structure protruding towards the electrode assembly 22 or away from the electrode assembly 22. The surface of the pressure relief mechanism 213 facing the electrode assembly 22 does not exceed the surface of the support structure 215 facing the electrode assembly 22.

[0241] The battery cell further comprises a protection member 216 fixed to a side of the first wall 201 facing the electrode assembly 22, the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the electrode assembly 22 both protrude from the surface of the first wall 201 facing the electrode assembly 22, and the surface 2161 of the protection member 216 facing the electrode assembly 22 protrudes from the surfaces of the support structure 215 and the pressure relief mechanism 213 facing the electrode assembly 22.

[0242] The protection piece 216 comprises a first part 2163 and a second part 2164 which are arranged at intervals, and the pressure relief mechanism 213 and the support structure 215 are located between the first part 2163 and the second part 2164. Alternatively, the protection piece 216 is provided with an avoiding opening 2162 which is used for avoiding the pressure relief mechanism 213 and the support structure 215. Alternatively, the protection piece 216 is provided with a groove 2166 which is open to the pressure relief mechanism 213, the groove 2166 is used for accommodating the pressure relief mechanism 213 and the support structure 215, and the bottom of the groove 2166 is provided with a thinned area 2167 corresponding to the pressure relief mechanism 213, and the thickness of the thinned area 2167 is less than the thickness of other areas of the bottom of the groove 2166.

[0243] The pressure relief mechanism 213, the inner wall of the pressure relief hole 202 and the support structure 215 are connected by the same welding seam which is located on the side of the support structure 215 away from the electrode assembly 22. Alternatively, the pressure relief mechanism 213 and the support structure 215 are connected by the same welding seam, the first wall 201 and the support structure 215 are connected by the same welding seam, and the welding seam between the pressure relief mechanism 213 and the support structure 215 is different from the welding seam between the first wall 201 and the support structure 215. Alternatively, the pressure relief mechanism 213, the support structure 215 and the first wall 201 are arranged in a stacked manner along the thickness direction of the first wall 201, and the pressure relief mechanism 213, the support structure 215 and the first wall 201 are connected by the same welding seam.

[0244] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized by, The shell (211) has a first wall (201) provided with a pressure relief hole (202); an electrode assembly (22) is accommodated in the shell (211); a pressure relief mechanism (213) covers the pressure relief hole (202); a support structure (215) is fixed to a side of the first wall (201) facing the electrode assembly (22), the pressure relief mechanism (213) is located on a side of the support structure (215) away from the electrode assembly (22), and the pressure relief mechanism (213) is welded to at least one of the support structure (215) and the first wall (201). The support structure (215) and the first wall (201) are fixed by welding or by adhesion. The materials of the pressure relief mechanism (213), the support structure (215) and the first wall (201) include iron, copper or titanium. The thickness of the shell (211) ranges from 0.075mm to 0.4mm; and / or, The thickness of the pressure relief mechanism (213) ranges from 0.075mm to 0.4mm.

2. The battery cell of claim 1, wherein, The thickness of the shell (211) ranges from 0.075mm to 0.25mm; and / or, 3. The battery cell according to claim 1 or 2, characterized in that, The thickness of the pressure relief mechanism (213) ranges from 0.075mm to 0.25mm.

4. The battery cell of claim 3, wherein, The pressure relief mechanism (213), the inner wall of the pressure relief hole (202) and the support structure (215) are connected by the same weld, which is located on a side of the support structure (215) away from the electrode assembly (22). The pressure relief mechanism (213) and the support structure (215) are connected by the same weld, and the first wall (201) and the support structure (215) are connected by the same weld, and the weld between the pressure relief mechanism (213) and the support structure (215) is different from the weld between the first wall (201) and the support structure (215).

5. The battery cell according to claim 3 or 4, characterized in that, The pressure relief mechanism (213), the support structure (215) and the first wall (201) are stacked along the thickness direction of the first wall (201), and the pressure relief mechanism (213), the support structure (215) and the first wall (201) are connected by the same weld. The pressure relief mechanism (213), the support structure (215) and the first wall (201) have at least one weld, 6. The battery cell according to any one of claims 1 to 5, characterized in that, Along the thickness direction of the first wall (201), the orthographic projection of the at least one weld towards the outer surface of the support structure (215) is located in the middle region of the outer surface of the support structure (215), and the outer surface of the support structure (215) is the surface of the support structure (215) away from the electrode assembly (22).

7. The battery cell according to any one of claims 1 to 5, characterized in that, Along the thickness direction of the first wall (201), the orthographic projection of the at least one weld towards the outer surface of the support structure (215) is symmetrically distributed relative to the center line of the outer surface of the support structure (215).

8. The battery cell of any one of claims 1 to 5, wherein, ​ 9. The battery cell of any one of claims 1 to 8, wherein, ​ ​ 10. The battery cell of claim 9, wherein, ​ 11. The battery cell according to claim 9 or 10, characterized in that A side of the weld facing the electrode assembly (22) does not exceed a surface of the support structure (215) facing the electrode assembly (22).

12. The battery cell of any one of claims 1 to 11, wherein, The base material of the pressure relief mechanism (213) is iron; the pressure relief mechanism (213) comprises a weak portion (2132), a body portion (2131) and a connecting portion (2133), the weak portion (2132) is configured to be destroyed to release pressure when the pressure inside the shell (211) reaches a threshold value, the body portion (2131) is located in the area surrounded by the weak portion (2132), and the connecting portion (2133) is located outside the weak portion (2132) and is used to connect the first wall (201); the body portion (2131) is a protruding structure facing the direction close to the electrode assembly (22) or the direction away from the electrode assembly (22).

13. The battery cell of claim 12, wherein, The connecting portion (2133) comprises a fixed area (2135) and a transition area (2136), the fixed area (2135) is used to connect with the first wall (201), and the transition area (2136) is used to connect the fixed area (2135) and the weak portion (2132), the fixed area (2135) is arranged in parallel with respect to the first wall (201), The transition area (2136) is flush with the fixed area (2135), or the transition area (2136) protrudes towards the direction close to the electrode assembly (22) with respect to the fixed area (2135), and the body portion (2131) protrudes towards the direction close to the electrode assembly (22) with respect to the fixed area (2135), The surface of the body portion (2131) facing the electrode assembly (22) does not exceed the surface of the support structure (215) facing the electrode assembly (22) along the thickness direction of the pressure relief mechanism (213) and from the pressure relief mechanism (213) to the electrode assembly (22).

14. The battery cell of claim 12, wherein, The connecting portion (2133) comprises a fixed area (2135) and a transition area (2136), the fixed area (2135) is used to connect with the first wall (201), and the transition area (2136) is used to connect the fixed area (2135) and the weak portion (2132), the fixed area (2135) is arranged in parallel with respect to the first wall (201), The transition area (2136) and the body portion (2131) both protrude away from the electrode assembly (22) with respect to the weak portion (2132), The surface of the weak portion (2132) facing the electrode assembly (22) does not exceed the surface of the support structure (215) facing the electrode assembly (22) along the thickness direction of the pressure relief mechanism (213) and from the pressure relief mechanism (213) to the electrode assembly (22).

15. The battery cell of any one of claims 1 to 14, wherein, The thickness of the support structure (215) ranges from [0.4mm, 1.5mm].

16. The battery cell of any one of claims 1 to 15, wherein, The thickness of the support structure (215) ranges from [0.4mm, 0.8mm].

17. The battery cell of any one of claims 1 to 16, wherein, The battery monomer further comprises: A protection member (216) is fixed to a side of the first wall (201) facing the electrode assembly (22), surfaces of the support structure (215) and the pressure relief mechanism (213) facing the electrode assembly (22) are protruded from a surface of the first wall (201) facing the electrode assembly (22), and a surface (2161) of the protection member (216) facing the electrode assembly (22) is protruded from the surfaces of the support structure (215) and the pressure relief mechanism (213) facing the electrode assembly (22).

18. The battery cell of claim 17, wherein, The protection member (216) comprises a first part (2163) and a second part (2164) arranged at intervals, and the pressure relief mechanism (213) and the support structure (215) are located between the first part (2163) and the second part (2164).

19. The battery cell of claim 17, wherein, The protection member (216) is provided with a relief opening (2162) for avoiding the pressure relief mechanism (213) and the support structure (215).

20. The battery cell of claim 17, wherein, The protection member (216) is provided with a groove (2166) facing the pressure relief mechanism (213), the groove (2166) is used for accommodating the pressure relief mechanism (213) and the support structure (215), a bottom of the groove (2166) is provided with a thinning area (2167) corresponding to the pressure relief mechanism (213), and a thickness of the thinning area (2167) is less than a thickness of other areas of the bottom of the groove (2166).

21. A battery device, characterized by Comprise: A plurality of battery monomers, the battery monomers are the battery monomers as claimed in any one of claims 1 to 20.

22. An electrical device, comprising: Comprise: A battery device, the battery device comprises the battery monomers as claimed in any one of claims 1 to 20, and the battery device is used for supplying power for the electric equipment.

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