Pressure relief devices, battery cells, batteries and power consumption devices

Abstract

The present invention provides a pressure relief device, a battery cell, a battery, and a power consumption device, all of which belong to the battery technology field. The pressure relief device includes a pressure relief portion and a multi-stage cut groove. The pressure relief portion has a first surface and a second surface that are arranged opposite each other in the thickness direction. The multi-stage cut grooves are arranged on the pressure relief portion in order from the first surface to the second surface, and of two adjacent cut grooves, the cut groove farthest from the first surface is arranged on the bottom surface of the cut groove closest to the first surface. The pressure relief portion has an opening region, and the cut grooves are arranged along the edge of the opening region, and the opening region is opened with the cut groove farthest from the first surface as its boundary. The pressure relief device employs a multi-stage cut groove structure, which reduces the molding force exerted on the pressure relief portion when molding each cut groove, reducing the risk of cracks occurring in the pressure relief portion. This reduces the risk of pressure relief device failure due to cracks occurring at the cut grooves, thereby improving the long-term reliability of the pressure relief device.

Description

[Technical Field]

[0001] The present application relates to the field of battery technology, and in particular to a pressure relief device, a battery cell, a battery, and a power consuming device.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to International Patent Application PCT / CN2021 / 115766, entitled "Pressure Discharge Device, Battery Cell, Battery, and Power Consumption Device," filed on August 31, 2021, the entire contents of which are incorporated herein by reference. [Background technology]

[0003] Batteries are widely used in electronic devices, such as mobile phones, notebook computers, battery-powered vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools.

[0004] In battery technology, to ensure the safety of battery cells, a pressure relief device is generally installed in the battery cell, and when the internal pressure or temperature of the battery cell reaches a threshold, the pressure relief device will burst at the position where the notch is installed to release the internal pressure of the battery cell. However, with a typical pressure relief device, there is a possibility that the pressure will be relieved even when the internal pressure of the battery cell is within the normal range, resulting in low long-term reliability. Summary of the Invention

[0005] The embodiments of the present application provide a pressure relief device, a battery cell, a battery, and a power consuming device that can effectively improve the long-term reliability of the pressure relief device.

[0006] According to a first aspect, an embodiment of the present application provides a pressure relief device, the pressure relief device including a pressure relief portion and a multi-stage cut groove, the pressure relief portion having a first surface and a second surface arranged opposite each other in its thickness direction, the multi-stage cut grooves arranged in order in the pressure relief portion along the direction from the first surface to the second surface, and of two adjacent cut groove stages, the cut groove stage farthest from the first surface is arranged on the bottom surface of the cut groove stage close to the first surface, wherein the pressure relief portion has an opening region, the cut grooves are arranged along the edge of the opening region, and the opening region is arranged so as to be open with the cut groove stage farthest from the first surface as the boundary.

[0007] In the above technical solution, the multi-stage cut grooves are installed in the pressure relief section in sequence along the direction from the first surface to the second surface, and the pressure relief device adopts a multi-stage cut groove structure, which can reduce the forming depth of each stage of the cut groove, thereby reducing the forming force received by the pressure relief section when forming each stage of the cut groove, reducing the risk of cracks occurring in the pressure relief section, making it less likely that the pressure relief device will fail due to cracks occurring at the positions where the cut grooves are installed, and improving the long-term reliability of the pressure relief device.

[0008] In some embodiments, the cut groove includes a first groove segment, a second groove segment, and a third groove segment, the first groove segment and the second groove segment are disposed opposite each other, the first groove segment and the second groove segment both intersect with the third groove segment, and the first groove segment, the second groove segment, and the third groove segment are disposed along the edge of the opening region. In this way, the opening region can be opened with the first groove segment, the second groove segment, and the third groove segment as boundaries, thereby increasing the pressure relief area of ​​the pressure relief portion and improving the pressure relief speed of the pressure relief portion.

[0009] In some embodiments, the pressure relief portion includes a fourth groove segment located between the first groove segment and the second groove segment and intersecting with the third groove segment, where stress is more concentrated and more likely to rupture, so that during pressure relief, the pressure relief portion ruptures along the third groove segment from the intersecting position of the third groove segment and the fourth groove segment, and then ruptures along the first and second groove segments after the third groove segment ruptures, thereby achieving rapid pressure relief.

[0010] In some embodiments, the fourth groove segment and the third groove segment intersect at an intersection position, and the distance from the intersection position to the first groove segment in the extension direction of the third groove segment is equal to the distance from the intersection position to the second groove segment. In this way, the pressure relief portion can rupture along the third groove segment from the intersection position of the fourth groove segment and the third groove segment, and then rupture along the first groove segment and the second groove segment synchronously, thereby allowing the opening region to open more quickly.

[0011] In some embodiments, the first groove segment, the second groove segment, and the third groove segment jointly define at least one open area, which can be opened in a reverse manner, and after opening the open area, it always connects to other areas of the pressure relief part, making it less likely to fall off and reducing the risk of splashing after opening the open area.

[0012] In some embodiments, the first groove segment, the second groove segment, and the third groove segment define two opening areas, and the two opening areas are located on both sides of the third groove segment, respectively. During the pressure relief process of the pressure relief part, the two opening areas of the pressure relief part can be opened in a double-door manner to release pressure, thereby expanding the pressure relief area and effectively improving the pressure relief speed of the pressure relief part.

[0013] In some embodiments, the cut groove further includes a fifth groove segment located opposite the third groove segment, the first groove segment and the second groove segment both intersect with the fifth groove segment, and the first groove segment, the second groove segment, the third groove segment, and the fifth groove segment jointly define an open area. In this way, the open area is a closed area defined by the first groove segment, the second groove segment, the third groove segment, and the fifth groove segment, and during the pressure relief process of the pressure relief portion, the pressure relief portion can rupture along the first groove segment, the second groove segment, the third groove segment, and the fifth groove segment, thereby opening the open area in a detached manner, increasing the pressure relief area of ​​the pressure relief portion and improving the pressure relief speed of the pressure relief portion.

[0014] In some embodiments, the cut groove is a non-closing groove that extends along a non-closing path with no end connection, so that the opening area can be opened in a reverse manner, and after opening the opening area, it always connects to other areas of the pressure relief part, making it less likely to fall off and reducing the risk of splashing after opening the opening area.

[0015] In some embodiments, the cut groove is arc-shaped. The arc-shaped cut groove has a simple structure and is easy to form. When pressure is released, the pressure release portion can quickly burst along the arc-shaped cut groove, thereby quickly opening the opening area.

[0016] In some embodiments, the cut groove is a closing groove extending along a closing path with both ends connected. During the pressure relief process of the pressure relief part, the pressure relief part can be ruptured along the cut groove, so that the opening area can be opened in a detached manner, the pressure relief area of ​​the pressure relief part can be enlarged, and the pressure relief speed of the pressure relief part can be improved.

[0017] In some embodiments, the notch is annular. The annular notch has a simple structure and is easy to form. When pressure is released, the pressure release portion can quickly burst along the annular notch, thereby quickly opening the opening area.

[0018] In some embodiments, the pressure relief section has two or three cut grooves.

[0019] In some embodiments, the outermost single-stage groove is formed on the first surface along the thickness direction, which simplifies the structure of the pressure relief device and reduces production costs by directly forming the outermost single-stage groove on the first surface.

[0020] In some embodiments, the pressure relief device further includes at least one sunken groove, and the at least one sunken groove and the plurality of cut grooves are arranged in the pressure relief portion in sequence from the first surface to the second surface, with the open region formed in the groove bottom wall of the first sunken groove farthest from the first surface. By first forming the sunken groove in the pressure relief portion, the region of the pressure relief portion where the sunken groove is located is generally thinned, increasing the hardness of the remainder of the region. By then forming the cut groove in the pressure relief portion, the hardness of the remainder of the pressure relief portion in the cut groove region is further increased, improving long-term reliability, providing higher impact resistance, and reducing the likelihood of breakage due to external impact. Furthermore, because the open region is formed in the groove bottom wall of the first sunken groove farthest from the first surface, the sunken groove can provide a retreat space during the opening region opening, so that even if the first surface is blocked by an obstacle, the open region can still open to relieve pressure.

[0021] In some embodiments, the pressure relief device includes a single-stage recess, the recess is located on the first surface, and the single-stage notch closest to the first surface is located on the bottom surface of the recess. The single-stage recess is located on the pressure relief device, which simplifies molding, improves production efficiency, and reduces production costs.

[0022] In some embodiments, the pressure relief device includes a multi-stage sunken groove, and the multi-stage sunken grooves are arranged in order in the pressure relief portion along a direction from the first surface to the second surface, and of two adjacent stages of sunken grooves, the stage of sunken groove farthest from the first surface is arranged on a bottom surface of the stage of sunken groove closest to the first surface, and in this case, along the thickness direction, the outermost stage of sunken groove is arranged on the first surface, and the stage of cut groove closest to the first surface is arranged on a bottom surface of the stage of sunken groove farthest from the first surface. By providing the multi-stage sunken grooves in the pressure relief portion, the forming depth of each stage of sunken groove can be made relatively shallow, which reduces the forming force received by the pressure relief portion when forming each stage of sunken groove, and reduces the risk of cracks occurring in the pressure relief portion. When multiple stages of sunken grooves are machined one stage at a time along the direction from the first surface to the second surface, the hardness of the remaining part in the area where the sunken groove of the pressure relief part is installed increases with each stage of the sunken groove being machined, thereby further increasing the hardness of the remaining part in the cut groove area of ​​the pressure relief part.

[0023] In some embodiments, the recessed groove is a rectangular groove or a circular groove, which has a simple structure, is easy to form, and can provide more escape space for opening the opening area.

[0024] In some embodiments, a flange is provided on the first surface, and the flange surrounds a single-stage recess provided on the first surface. The flange can reinforce the pressure relief portion and improve the deformation resistance of the pressure relief area of ​​the pressure relief portion. The flange also serves to attach a protective member, thereby protecting the opening area.

[0025] In some embodiments, a portion of the pressure relief portion protrudes from the second surface in a direction away from the first surface to form a convex portion, the convex portion including a groove bottom wall and a reinforcing portion, the reinforcing portion being connected to the second surface and surrounding the periphery of the groove bottom wall. By connecting the reinforcing portion to the second surface, the groove bottom wall can be reinforced, improving the deformation resistance of the groove bottom wall and reducing the risk of damage to the groove bottom wall at the location where the notch is installed.

[0026] In some embodiments, a groove is provided on the second surface, surrounding the protrusion, so that the pressure relief part can absorb the energy transmitted to the protrusion when subjected to force, and even if the pressure relief part is deformed, the energy is less likely to be transmitted to the area where the groove is provided.

[0027] In some embodiments, the height of the protrusion from the second surface along the thickness direction is H1, and the distance between the first surface and the second surface is H2, where H1 ≥ H2 is satisfied. In this way, the height of the protrusion from the second surface is increased, thereby enhancing the reinforcing effect of the reinforcing portion on the groove bottom wall.

[0028] In some embodiments, the maximum width of the groove in one step farther from the first surface of two adjacent groove stages is smaller than the minimum width of the groove in one step closer to the first surface. When molding, the grooves in each step can be molded sequentially along the direction from the first surface to the second surface, thereby facilitating the molding of the grooves in each step.

[0029] In some embodiments, the pressure relief part is an end cap, which is used to close the opening of the case, and the end cap is provided with a pressure relief function, and a pressure relief structure is formed by installing a notch on the end cap, which has higher stability and good long-term reliability.

[0030] In some embodiments, the first surface is a surface of the end cap facing away from the case.

[0031] In some embodiments, the pressure relief device is a case, the interior of the case forms an accommodating space, the case includes a plurality of walls, the plurality of walls jointly define the accommodating space, the accommodating space is for accommodating the electrode assembly, and at least one of the walls is a pressure relief device. The pressure relief device having such a structure has a accommodating function for accommodating the electrode assembly and a pressure relief function.

[0032] In some embodiments, the case includes a peripheral wall and a bottom wall, the peripheral wall is disposed around an edge of the bottom wall, the peripheral wall and the bottom wall jointly define the storage space, the end of the peripheral wall facing the bottom wall forms an opening, and the bottom wall is a pressure relief part, whereby the bottom wall of the pressure relief device has a pressure relief function and can easily release pressure inside the storage space.

[0033] In some embodiments, the first surface is the exterior surface of the wall. In this manner, the grooves can be machined into the exterior of the wall, which facilitates machining the grooves on the bottom wall.

[0034] According to a second aspect, an embodiment of the present application provides a battery cell including a pressure relief device according to any one of the embodiments of the first aspect.

[0035] According to a third aspect, an embodiment of the present application provides a battery including a battery cell according to any one of the embodiments of the second aspect.

[0036] According to a fourth aspect, an embodiment of the present application provides a power consuming device including a battery according to any one of the embodiments of the third aspect above. [Brief explanation of the drawings]

[0037] In order to more clearly explain the technical solutions of the embodiments of the present application, the following provides a brief description of the drawings that need to be used in the embodiments. It should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limitations on the scope of the claims. Those skilled in the art can further obtain other related drawings based on these drawings without exerting any creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Figure 2] 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Figure 3] FIG. 1 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] 1 is a perspective view of a pressure relief device according to some embodiments of the present application; [Figure 5] FIG. 5 is a plan view of the pressure relief device shown in FIG. [Figure 6] 6 is a cross-sectional view of the pressure relief device shown in FIG. 5 along the line AA. [Figure 7] 6 is a partial enlarged view of a portion B of the pressure relief device shown in FIG. 5. [Figure 8] 1 is a partial enlarged view of a pressure relief device according to some embodiments of the present application. [Figure 9] 10 is a partial enlarged view of a pressure relief device according to some further embodiments of the present application. [Figure 10] 10 is a partial enlarged view of a pressure relief device according to still other embodiments of the present application. [Figure 11] 10A and 10B are enlarged partial views of a pressure relief device according to some other embodiments of the present application. [Figure 12] 7 is a partial enlarged view of a portion C of the pressure relief device shown in FIG. 6. [Figure 13] 10A and 10B are partial cross-sectional views of pressure relief devices according to some alternative embodiments of the present application. [Figure 14] 1 is a perspective view of a pressure relief device according to some embodiments of the present application; [Figure 15] FIG. 15 is a plan view of the pressure relief device shown in FIG. [Figure 16] 15 is a partial enlarged view of a portion D of the pressure relief device shown in FIG. 14. [Figure 17] 16 is a cross-sectional view of the pressure relief device shown in FIG. 15 . [Figure 18] 10 is a perspective view of a pressure relief device according to still other embodiments of the present application. [Figure 19] FIG. 19 is a plan view of the pressure relief device shown in FIG. [Figure 20] FIG. 19 is a partial enlarged view of a portion F of the pressure relief device shown in FIG. [Figure 21] FIG. 20 is a cross-sectional view of the pressure relief device shown in FIG. [Figure 22] 10 is a perspective view of a pressure relief device according to some other embodiments of the present application. [Figure 23] 23 is a partial enlarged view of a portion H of the pressure relief device shown in FIG. 22. DETAILED DESCRIPTION OF THE INVENTION

[0038] In order to clarify the objectives, technical solutions, and advantages of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly explained below in conjunction with the embodiments and drawings. It is clear that the described embodiments are only a part of the embodiments of the present application, and do not include all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without any creative effort fall within the scope of protection of the present application.

[0039] Unless otherwise defined, all scientific and technical terms used in this application have the same meaning as commonly understood by those skilled in the art. In this application, the terms used in the specification of the application are used only to describe specific embodiments and are not intended to limit the application. The terms "comprises," "has," and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover a non-exclusive "comprises." The terms "first," "second," etc. in the specification and claims of this application or the above-mentioned drawings are intended to distinguish different objects and are not intended to describe a specific order or a primary-subordinate relationship.

[0040] An "embodiment" referred to in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification do not necessarily all refer to the same embodiment, nor are they mutually exclusive, separate, or alternative embodiments of other embodiments.

[0041] In the description of this application, it should be explained that unless otherwise specified and limited, the terms "attached," "connected," "coupled," and "attached" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a direct connection, an indirect connection via an intermediate medium, or communication between the interiors of two elements. Those skilled in the art can understand the specific meanings of the above terms in the present application according to specific circumstances.

[0042] The term "and / or" in this application merely describes the relationship between related objects and indicates that three relationships may exist, for example, A and / or B may represent three cases: A alone, a combination of A and B, and B alone. Also, the character " / " in this application generally indicates that the related objects before and after are in an "or" relationship.

[0043] In the embodiments of the present application, the same reference numerals represent the same elements, and for the sake of brevity, detailed descriptions of the same elements in different embodiments will be omitted. Note that the dimensions such as thickness, length, and width of each member in the embodiments of the present application and the overall dimensions such as thickness, length, and width of the integrated device shown in the drawings are merely illustrative and do not limit the present application.

[0044] In this application, "plurality" refers to two or more (including two).

[0045] In this application, the battery cells may include lithium ion secondary batteries, lithium ion primary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries, magnesium ion batteries, etc., but are not limited to these in the embodiments of this application. The battery cells may be cylindrical, flat, rectangular, or have other shapes, but are not limited to these in the embodiments of this application. Battery cells are generally divided into three types based on their packaging: prismatic battery cells, rectangular battery cells, and flexible pouch battery cells, but are not limited to these in the embodiments of this application.

[0046] The battery referred to in the examples of this application refers to a single physical module containing one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. The battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells.

[0047] A battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode plate, a negative electrode plate, and a separator. The battery cell operates mainly by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector without the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector without the positive electrode active material layer is called a positive electrode tab. Taking a lithium-ion battery as an example, the positive electrode current collector may be made of aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganese oxide, etc. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector not coated with the negative electrode active material layer protrudes from the negative electrode current collector coated with the negative electrode active material layer. The negative electrode current collector not coated with the negative electrode active material layer is referred to as a negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon. To prevent melting even when a large current is passed through the positive electrode tab, multiple positive electrode tabs are stacked, and multiple negative electrode tabs are stacked. The separator may be made of polypropylene (PP) or polyethylene (PE). The electrode assembly may have a wound structure or a stacked structure, but the embodiments of the present application are not limited thereto.

[0048] The development of battery technology requires simultaneous consideration of a wide range of design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate, as well as battery safety.

[0049] The pressure relief device in a battery cell has an important impact on battery safety. For example, when a short circuit or overcharging occurs, thermal runaway can occur inside the battery cell, causing a sudden rise in pressure or temperature. In such cases, the pressure relief mechanism can be activated to release the internal pressure or temperature to the outside, preventing the battery cell from exploding or catching fire.

[0050] The inventors discovered that in common battery cells, the pressure relief device may release pressure even when the internal pressure of the battery cell is within a normal range, resulting in battery cell failure. Further research and discovery by the inventors revealed that, while pressure relief devices generally have a notch in the pressure relief section, in order to ensure that the pressure relief device can normally release pressure when the internal pressure or temperature of the battery cell reaches a threshold, the notch needs to be machined deep enough, which makes it easy for cracks to occur after the notch on the pressure relief section is formed, resulting in a situation where the pressure relief device releases pressure even when the internal pressure of the battery cell is within a normal range (below the threshold).

[0051] In view of this, an embodiment of the present application provides a pressure relief device, in which a plurality of cut grooves are arranged in sequence in the pressure relief portion of the pressure relief device in a direction from a first surface to a second surface, and among two adjacent cut grooves, the cut groove of one stage farthest from the first surface is located on the bottom surface of the cut groove of one stage closer to the first surface, wherein the pressure relief portion has an opening region, and the cut grooves are arranged along the edge of the opening region, and the opening region is arranged so that it can be opened with the cut groove of the one stage farthest from the first surface as a boundary.

[0052] In such a pressure relief device, the multi-stage cut grooves are installed in the pressure relief section in sequence along the direction from the first surface to the second surface, and the pressure relief device adopts a multi-stage cut groove structure, which can reduce the molding depth of the cut grooves of each stage, thereby reducing the molding force that the pressure relief section receives when molding the cut grooves of each stage, reducing the risk of cracks occurring in the pressure relief section, making it less likely that the pressure relief device will fail due to cracks occurring at the positions where the cut grooves are installed, and improving the long-term reliability of the pressure relief device.

[0053] The pressure relief device described in the embodiments of the present application is applicable to batteries and power consuming devices that use batteries.

[0054] The power consuming devices may be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools. The vehicles may be fuel oil vehicles, gas vehicles, or new energy vehicles. The new energy vehicles may be pure electric vehicles, hybrid vehicles, or range extender vehicles. The spacecraft may include airplanes, rockets, space shuttles, and spaceships. The electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric plane toys. The power tools may include metal cutting power tools, polishing power tools, assembly power tools, and railroad power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, hammer drills, concrete vibrators, and electric planes. The embodiments of the present application are not particularly limited to the above power consuming devices.

[0055] In the following embodiment, for ease of explanation, the power consuming device is a vehicle.

[0056] Referring to Fig. 1, Fig. 1 is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application. A battery 100 is installed inside the vehicle 1000, and the battery 100 can be installed at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be an operating power source for the vehicle 1000.

[0057] The vehicle 1000 may further include a controller 200 and a motor 300, where the controller 200 controls the battery 100 to power the motor 300 for use in, for example, starting, navigating, and running the vehicle 1000 for its operating power needs.

[0058] In some embodiments of the present application, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, fuel oil or natural gas.

[0059] 2, which is a structural schematic diagram of a battery 100 according to some embodiments of the present application. The battery 100 includes a battery cell 10 and a housing 20, and the housing 20 is for housing the battery cell 10.

[0060] Here, the housing 20 is a member that houses the battery cells 10, and the housing 20 provides an accommodation space for the battery cells 10. The housing 20 may have various structures. In some embodiments, the housing 20 may include a first portion 201 and a second portion 202, and the first portion 201 and the second portion 202 are fitted together to define an accommodation space for accommodating the battery cells 10. The first portion 201 and the second portion 202 may have various shapes, such as a rectangular parallelepiped or a cylindrical body. The first portion 201 may have a hollow structure with one side open, and the second portion 202 may have a hollow structure with one side open, and the open side of the second portion 202 is fitted over the open side of the first portion 201 to form the housing 20 having an accommodation space. The first part 201 may have a hollow structure with one side open, and the second part 202 may have a plate-like structure, and the second part 202 may be placed over the open side of the first part 201 to form a housing 20 having an accommodation space. The first part 201 and the second part 202 may be sealed by a sealing element, which may be a sealing ring, a sealant, etc.

[0061] The battery 100 may have one or more battery cells 10. If there are multiple battery cells 10, the multiple battery cells 10 may be connected in series, parallel, or series-parallel, and a series-parallel connection means that the multiple battery cells 10 are connected in both series and parallel. A battery module may first be formed by connecting the multiple battery cells 10 in series, parallel, or series-parallel, and then the multiple battery modules may be connected in series, parallel, or series-parallel to form an integrated battery module, which may then be housed in the housing 20. All of the battery cells 10 may be directly connected in series, parallel, or series-parallel, and then the entire battery module made up of all of the battery cells 10 may be housed in the housing 20.

[0062] In some embodiments, the battery 100 may further include bus bar members, and the bus bar members may be used to realize electrical connections between the multiple battery cells 10, thereby enabling series connection, parallel connection, or series-parallel connection of the multiple battery cells 10. The bus bar members may be made of a metal conductor, such as copper, iron, aluminum, stainless steel, or an aluminum alloy.

[0063] 3, which is an exploded view of a battery cell 10 according to some embodiments of the present application. The battery cell 10 includes a case 1, an electrode assembly 2, an end cap 3, an insulating member 5, and a pressure relief device 6 (not shown in FIG. 3).

[0064] The case 1 is a member for housing the electrode assembly 2, and may be a hollow structure with an opening at one end. The case 1 may have various shapes, such as a cylinder or a rectangle. The case 1 may be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0065] There may be one or more electrode assemblies 2 in the case 1. For example, as shown in Fig. 3, there are multiple electrode assemblies 2, and the multiple electrode assemblies 2 are stacked and arranged in the case 1.

[0066] The electrode assembly 2 is a component where an electrochemical reaction occurs in the battery cell 10. The electrode assembly 2 may include a positive electrode plate, a negative electrode plate, and a separator. The electrode assembly 2 may have a wound structure formed by winding a positive electrode plate, a separator, and a negative electrode plate, or may have a stacked structure formed by stacking and arranging a positive electrode plate, a separator, and a negative electrode plate.

[0067] The positive electrode plate may include a positive electrode current collector and a positive electrode active material layer coated on both opposing sides of the positive electrode current collector. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on both opposing sides of the negative electrode current collector. The electrode assembly 2 includes a positive electrode tab 21 and a negative electrode tab 22. The positive electrode tab 21 may be a portion of the positive electrode plate that is not coated with the positive electrode active material layer, and the negative electrode tab 22 may be a portion of the negative electrode plate that is not coated with the negative electrode active material layer.

[0068] The end cap 3 is a component that covers the opening of the case 1 and isolates the internal environment of the battery cell 10 from the external environment. The end cap 3 covers the opening of the case 1, and the end cap 3 and the case 1 together define an enclosed space for accommodating the electrode assembly 2, electrolyte, and other components. The shape of the end cap 3 may be adapted to the shape of the case 1. For example, the case 1 may have a rectangular parallelepiped structure and the end cap 3 may have a rectangular plate-like structure that fits the case 1. Alternatively, the case 1 may have a cylindrical structure and the end cap 3 may have a circular plate-like structure that fits the case 1. The material of the end cap 3 may be various, such as copper, iron, aluminum, steel, aluminum alloy, etc., and the material of the end cap 3 and the material of the case 1 may be the same or different.

[0069] Electrode terminals may be installed on the end cap 3, and are electrically connected to the electrode assembly 2 to output electrical energy from the battery cell 10. The electrode terminals may include a positive electrode terminal 31 and a negative electrode terminal 32. The positive electrode terminal 31 is used to electrically connect to the positive electrode tab 21, and the negative electrode terminal 32 is used to electrically connect to the negative electrode tab 22. The positive electrode terminal 31 and the positive electrode tab 21 may be directly or indirectly connected, and the negative electrode terminal 32 and the negative electrode tab 22 may be directly or indirectly connected. Exemplarily, the positive electrode terminal 31 is electrically connected to the positive electrode tab 21 via one current collecting component 4, and the negative electrode terminal 32 is electrically connected to the negative electrode tab 22 via another current collecting component 4.

[0070] The insulating member 5 is a member that separates the case 1 and the electrode assembly 2, and the insulating member 5 realizes insulation and isolation between the case 1 and the electrode assembly 2. The insulating member 5 is made of an insulating material, and may be made of an insulating material such as plastic, rubber, etc. Exemplarily, the insulating member 5 circumferentially covers the outer periphery of the electrode assembly 2, and as can be understood, when there are multiple electrode assemblies 2, the insulating member 5 circumferentially covers the outer periphery of all of the multiple electrode assemblies 2.

[0071] The pressure relief device 6 is a component that releases the internal pressure of the battery cell 10, and when the internal pressure or temperature of the battery cell 10 reaches a threshold value, the internal pressure of the battery cell 10 is released by the pressure relief device 6. The pressure relief device 6 may be a component installed on the end cap 3, or the case 1 may be the pressure relief device 6, or the end cap 3 may be the pressure relief device 6. The specific structure of the pressure relief device 6 will be described in detail below with reference to the drawings.

[0072] 4 to 6, FIG. 4 is a perspective view of a pressure relief device 6 according to some embodiments of the present application, FIG. 5 is a plan view of the pressure relief device 6 shown in FIG. 4, and FIG. 6 is a cross-sectional view taken along line AA of the pressure relief device 6 shown in FIG. 5. The embodiments of the present application provide a pressure relief device 6 including a pressure relief portion 61 and a multi-stage cut groove 62. The pressure relief portion 61 has a first surface 611 and a second surface 612 that are arranged opposite each other in the thickness direction Z of the pressure relief portion 61. The multi-stage cut grooves 62 are arranged in order in the pressure relief portion 61 along the direction from the first surface 611 to the second surface 612, and of two adjacent cut grooves 62, the cut groove 62 farthest from the first surface 611 is arranged on the bottom surface of the cut groove 62 closer to the first surface 611. Here, the pressure relief portion 61 has an opening region 613, the cut grooves 62 are installed along the edge of the opening region 613, and the opening region 613 is arranged so that it can be opened with the one stage of the cut groove 62 that is farthest from the first surface 611 as its boundary.

[0073] The pressure relief portion 61 may be a component attached to the end cap 3, for example, the pressure relief portion 61 may be an explosion-proof sheet attached to the end cap 3, and the entire pressure relief portion 61 may be the end cap 3, or the pressure relief portion 61 may be a part of the case 1, for example, the pressure relief portion 61 may be one wall portion or one part of one wall portion of the case 1.

[0074] The first surface 611 and the second surface 612 of the pressure relief part 61 are two surfaces of the pressure relief part 61 facing each other in the thickness direction Z, and the distance between the first surface 611 and the second surface 612 is the thickness of the pressure relief part 61. For example, if the pressure relief part 61 is an end cap 3, the first surface 611 may be the outer surface of the end cap 3 facing the outside of the battery cell 10, and the second surface 612 may be the inner surface of the end cap 3 facing the inside of the battery cell 10.

[0075] The pressure relief portion 61 may have two, three, four, or five stages of cut grooves 62. Taking the pressure relief portion 61 having two stages of cut grooves 62 as an example, the two stages of cut grooves 62 are respectively a first stage cut groove 62 and a second stage cut groove 62, and the second stage cut groove 62 is located on the bottom surface of the first stage cut groove 62, the first stage cut groove 62 is closer to the first surface 611 than the second stage cut groove 62, and the second stage cut groove 62 is the first stage cut groove 62 farthest from the first surface 611. The cut grooves 62 may have various shapes, such as an arc shape, an H-shape, a U-shape, an annular shape, etc. The cut grooves 62 on the pressure relief portion 61 may be formed by various methods, such as press forming, milling, etc. For example, by using a press molding method to form multiple stages of cut grooves 62, multiple stages of cut grooves 62 may be press molded in sequence in the pressure relief portion 61 along the direction from the first surface 611 to the second surface 612.

[0076] The opening region 613 is the region where the pressure relief part 61 relieves pressure. When the internal pressure or temperature of the battery cell 10 reaches a threshold, the opening region 613 is opened at the cutout 62 at the farthest stage from the first surface 611, thereby realizing pressure relief. The opening region 613 may be opened by a separation method or an inversion method. The cutout 62 is arranged along the edge of the opening region 613, so that the shapes of the cutouts 62 at each stage are basically the same and are all arranged along the edge of the opening region 613.

[0077] In the embodiment of the present application, the multi-stage cut grooves 62 are installed in the pressure relief section 61 in sequence along the direction from the first surface 611 to the second surface 612, and the pressure relief device 6 adopts a structure of multi-stage cut grooves 62, which can reduce the molding depth of the cut grooves 62 of each stage, thereby reducing the molding force received by the pressure relief section 61 when molding the cut grooves 62 stage by stage, reducing the risk of cracks occurring in the pressure relief section 61, making the pressure relief device 6 less likely to fail due to cracks occurring at the positions where the cut grooves 62 are installed, and improving the long-term reliability of the pressure relief device 6.

[0078] When forming the multiple cut grooves 62 in the pressure relief portion 61, the cut grooves 62 may be formed in stages in the pressure relief portion 61 in the direction from the first surface 611 to the second surface 612, with the forming depth of each stage of the cut grooves 62 being relatively shallow, so that the forming force received by the pressure relief portion 61 is small, reducing the risk of cracks occurring in the pressure relief portion 61 and improving the flatness of the first surface 611. In the process of forming the multiple cut grooves 62 in stages in the direction from the first surface 611 to the second surface 612, the hardness of the remaining portion of the pressure relief portion 61 in the area where the cut grooves 62 are formed increases with each stage of the cut grooves 62 formed, thereby increasing the hardness of the remaining portion after the multiple cut grooves 62 are formed in the pressure relief portion 61, thereby improving long-term reliability, providing higher impact resistance, and reducing the probability of breakage due to impact from external forces.

[0079] Furthermore, since the cut grooves 62 are installed along the edges of the opening region 613, and the opening region 613 is opened with the one cut groove 62 farthest from the first surface 611 as the boundary, the pressure relief area of ​​the pressure relief section 61 is enlarged and the pressure relief speed of the pressure relief section 61 is improved.

[0080] In some embodiments, referring to Figure 7, Figure 7 is a partial enlarged view of section B of the pressure relief device 6 shown in Figure 5. The cut groove 62 includes a first groove segment 621, a second groove segment 622, and a third groove segment 623, where the first groove segment 621 and the second groove segment 622 are arranged opposite each other, the first groove segment 621 and the second groove segment 622 both intersect with the third groove segment 623, and the first groove segment 621, the second groove segment 622, and the third groove segment 623 are arranged along the edge of the opening region 613.

[0081] The first groove segment 621, the second groove segment 622, and the third groove segment 623 may all be linear grooves, the first groove segment 621 and the second groove segment 622 may be parallel, and the first groove segment 621 and the second groove segment 622 may be perpendicular to the third groove segment 623. The position where the first groove segment 621 and the third groove segment 623 intersect may be at one end of the third groove segment 623 or at a position away from the one end of the third groove segment 623, such that the one end of the third groove segment 623 extends beyond the first groove segment 621 along the extension direction of the third groove segment 623. The intersection of the second groove segment 622 and the third groove segment 623 may be at the other end of the third groove segment 623 or at a position away from the other end of the third groove segment 623, such that the other end of the third groove segment 623 extends beyond the second groove segment 622 along the extension direction of the third groove segment 623. The third groove segment 623 may be located at the end of the first groove segment 621 and the second groove segment 622, for example, the first groove segment 621, the third groove segment 623, and the second groove segment 622 are connected in order to form a U-shape. The third groove segment 623 may also be located at the center of the first groove segment 621 and the second groove segment 622, for example, as shown in FIG. 7, the first groove segment 621, the second groove segment 622, and the third groove segment 623 form an H-shape.

[0082] Of two adjacent stages of cut grooves 62, the first groove segment 621 in the stage of cut groove 62 farthest from the first surface 611 is located on the bottom surface of the first groove segment 621 in the stage of cut groove 62 close to the first surface 611, and the extending directions of the first groove segments 621 of the two adjacent stages are the same; the second groove segment 622 in the stage of cut groove 62 farthest from the first surface 611 is located on the bottom surface of the second groove segment 622 in the stage of cut groove 62 close to the first surface 611, and the extending directions of the second groove segments 622 of the two adjacent stages are the same; and the third groove segment 623 in the stage of cut groove 62 farthest from the first surface 611 is located on the bottom surface of the third groove segment 623 in the stage of cut groove 62 close to the first surface 611, and the extending directions of the third groove segments 623 of the two adjacent stages are the same.

[0083] In this embodiment, the opening area 613 can be opened with the boundaries of the first groove segment 621, the second groove segment 622 and the third groove segment 623, thereby expanding the pressure relief area of ​​the pressure relief section 61 and improving the pressure relief speed of the pressure relief section 61.

[0084] In some embodiments, refer to Figure 8, which is a partially enlarged view of a pressure relief device 6 according to some embodiments of the present application. A fourth groove segment 63 is installed in the pressure relief portion 61, and the fourth groove segment 63 is located between the first groove segment 621 and the second groove segment 622, and the fourth groove segment 63 intersects with the third groove segment 623.

[0085] The fourth groove segment 63 may be a straight groove. The fourth groove segment 63 and the cut grooves 62 are arranged correspondingly, and one-stage fourth groove segment 63 is arranged corresponding to one-stage cut groove 62. Among two adjacent fourth groove segments 63 along the direction from the first surface 611 to the second surface 612, the one-stage fourth groove segment 63 farther from the first surface 611 is arranged on the bottom surface of the one-stage fourth groove segment 63 closer to the first surface 611, so that the widths of the multi-stage fourth groove segments 63 gradually decrease.

[0086] The fourth groove segment 63 may be parallel to the first groove segment 621 and the second groove segment 622 and perpendicular to the third groove segment 623 .

[0087] Illustratively, the fourth groove segment 63 and the third groove segment 623 intersect at a midpoint of the fourth groove segment 63 and a midpoint of the third groove segment 623. The length of the fourth groove segment 63 is smaller than the lengths of the first groove segment 621 and the second groove segment 622.

[0088] The position where the fourth groove segment 63 and the third groove segment 623 intersect has a higher stress concentration and is more likely to rupture. Therefore, during the pressure release process, the pressure release part 61 ruptures along the third groove segment 623 from the intersection position between the third groove segment 623 and the fourth groove segment 63, and after the third groove segment 623 ruptures, it ruptures along the first groove segment 621 and the second groove segment 622, thereby realizing rapid pressure release.

[0089] In some embodiments, the fourth groove segment 63 and the third groove segment 623 intersect at an intersection position, and in the extension direction of the third groove segment 623, the distance from the intersection position to the first groove segment 621 is equal to the distance from the intersection position to the second groove segment 622.

[0090] The distance from the intersection point to the first groove segment 621 in the extension direction of the third groove segment 623 is the length of the portion of the third groove segment 623 between the fourth groove segment 63 and the first groove segment 621. The distance from the intersection point to the second groove segment 622 in the extension direction of the third groove segment 623 is the length of the portion of the third groove segment 623 between the fourth groove segment 63 and the second groove segment 622. For example, if both ends of the third groove segment 623 are connected to the first groove segment 621 and the second groove segment 622, respectively, and the fourth groove segment 63 is located at the center of the third groove segment 623, the distance from the intersection point to the first groove segment 621 will be equal to the distance from the intersection point to the second groove segment 622.

[0091] In this embodiment, the distance from the intersection of the fourth groove segment 63 and the third groove segment 623 to the first groove segment 621 is equal to the distance from the intersection of the fourth groove segment 63 and the third groove segment 623 to the second groove segment 622, so that the pressure relief portion 61 can rupture along the third groove segment 623 from the intersection of the fourth groove segment 63 and the third groove segment 623, and then synchronously rupture along the first groove segment 621 and the second groove segment 622, thereby enabling the opening region 613 to open more quickly.

[0092] In some embodiments, with continued reference to FIGS. 7 and 8, first groove segment 621 , second groove segment 622 and third groove segment 623 collectively define at least one open area 613 .

[0093] The open region 613 is jointly defined by the first groove segment 621, the second groove segment 622, and the third groove segment 623, and the cut groove 62 is not a closed structure. The open region 613 defined by the first groove segment 621, the second groove segment 622, and the third groove segment 623 may be one or two. For example, the first groove segment 621, the second groove segment 622, and the third groove segment 623 may form a U-shaped structure and the open region 613 is one. Alternatively, for example, the first groove segment 621, the second groove segment 622, and the third groove segment 623 may form an H-shaped structure and the open region 613 is two.

[0094] In this embodiment, the opening area 613 is jointly defined by the first groove segment 621, the second groove segment 622 and the third groove segment 623. The opening area 613 can be opened in an inverted manner. After the opening area 613 is opened, it always connects to other areas of the pressure relief part 61, making it less likely to fall off and reducing the risk of splashing after the opening area 613 is opened.

[0095] In some embodiments, with continued reference to Figures 7 and 8, the first groove segment 621, the second groove segment 622, and the third groove segment 623 define two opening regions 613, each located on either side of the third groove segment 623.

[0096] The first groove segment 621, the second groove segment 622, and the third groove segment 623 may jointly define two open regions 613, and the first groove segment 621, the second groove segment 622, and the third groove segment 623 may form an H-shaped structure. The third groove segment 623 and the first groove segment 621 may intersect at the midpoint of the first groove segment 621, and the third groove segment 623 and the second groove segment 622 may intersect at the midpoint of the second groove segment 622.

[0097] The two opening areas 613 are located on both sides of the third groove segment 623, so that the two opening areas 613 are bounded by the third groove segment 623. After the pressure relief section 61 ruptures at the position of the third groove segment 623, the two opening areas 613 are opened in a double door manner along the first groove segment 621 and the second groove segment 622 to realize pressure relief, thereby expanding the pressure relief area and effectively increasing the pressure relief speed of the pressure relief section 61.

[0098] 6 to 8, a notched groove 64 is provided in the opening region 613, and there is a distance between the notched groove 64 and the third groove segment 623 in the extending direction of the first groove segment 621.

[0099] The notched groove 64 may be located completely in the open region 613 or may be located partially in the open region 613 .

[0100] Illustratively, the notched groove 64 may be disposed on the second surface 612. The notched groove 64 may extend along the extension direction of the third groove segment 623, such that the notched groove 64 is parallel to the third groove segment 623.

[0101] In an embodiment in which the first groove segment 621, the second groove segment 622, and the third groove segment 623 jointly define one opening region 613, one notch groove 64 may be provided correspondingly. As shown in Figures 6 to 8, in an embodiment in which the first groove segment 621, the second groove segment 622, and the third groove segment 623 jointly define two opening regions 613, two notch grooves 64 may be provided correspondingly, with one notch groove 64 provided correspondingly for each opening region 613.

[0102] In this embodiment, the notch groove 64 is spaced apart from the third groove segment 623 in the extension direction of the first groove segment 621, and the notch groove 64 is located in the opening region 613, so that during the pressure relief process of the pressure relief section 61, a portion of the pressure relief section 61 located in the opening region 613 can be inverted around the position of the notch groove 64 of the pressure relief section 61 as an axis, making it easier to open the pressure relief section 61.

[0103] In some embodiments, refer to Figure 9, which is a partially enlarged view of a pressure relief device 6 according to some embodiments of the present application. The cut groove 62 further includes a fifth groove segment 624 disposed opposite the third groove segment 623, the first groove segment 621 and the second groove segment 622 both intersect with the fifth groove segment 624, and the first groove segment 621, the second groove segment 622, the third groove segment 623 and the fifth groove segment 624 collectively define an open area 613.

[0104] The fifth groove segment 624 may be disposed parallel to the third groove segment 623. The first groove segment 621, the third groove segment 623, the second groove segment 622, and the fifth groove segment 624 may be connected in sequence to form a closed structure. Of course, both ends of the first groove segment 621 may extend beyond the third groove segment 623 and the fifth groove segment 624, respectively; both ends of the second groove segment 622 may extend beyond the third groove segment 623 and the fifth groove segment 624, respectively; both ends of the third groove segment 623 may extend beyond the first groove segment 621 and the second groove segment 622, respectively; and both ends of the fifth groove segment 624 may extend beyond the first groove segment 621 and the second groove segment 622, respectively. Illustratively, in FIG. 9, the first groove segment 621, the third groove segment 623, the second groove segment 622 and the fifth groove segment 624 are connected head to tail to form a rectangular structure.

[0105] It should be noted that in this embodiment, the pressure relief portion 61 may have a fourth groove segment 63 or may not have a fourth groove segment 63 .

[0106] The opening region 613 is a closed region defined by the first groove segment 621, the second groove segment 622, the third groove segment 623 and the fifth groove segment 624. During the pressure relief process of the pressure relief part 61, the pressure relief part 61 can burst along the first groove segment 621, the second groove segment 622, the third groove segment 623 and the fifth groove segment 624, so that the opening region 613 can be opened in a detaching manner, and the pressure relief area of ​​the pressure relief part 61 is enlarged, and the pressure relief speed of the pressure relief part 61 is improved.

[0107] In some embodiments, referring to Figure 10, Figure 10 is a partial enlarged view of a pressure relief device 6 according to some further embodiments of the present application. The cut groove 62 is a non-closed groove that extends along a non-closed path with no connecting ends.

[0108] In this embodiment, the shape of the cut groove 62 may be various shapes, for example, an arc shape, a U-shape, or the like.

[0109] In this embodiment, the cut groove 62 is a non-closed groove that extends along a non-closed path with no connection at the beginning or end, and the opening area 613 can be opened in an inverted manner. After the opening area 613 is opened, it always connects to other areas of the pressure relief section 61, making it less likely to fall off and reducing the risk of splashing after the opening area 613 is opened.

[0110] 10 , in some embodiments, the cut groove 62 is arc-shaped. The arc-shaped cut groove 62 has a simple structure and is easy to form. When pressure is released, the pressure release portion 61 can quickly burst along the arc-shaped cut groove 62, thereby quickly opening the opening area 613.

[0111] In some embodiments, referring to Fig. 11, Fig. 11 is a partially enlarged view of a pressure relief device 6 according to some other embodiments of the present application. The cut groove 62 is a closed groove extending along a closed locus whose beginning and end are connected. In this embodiment, the shape of the cut groove 62 may be various shapes, such as a circular ring, a rectangular ring, etc.

[0112] During the pressure release process of the pressure release part 61, the pressure release part 61 can burst along the cut groove 62, so that the opening area 613 can be opened in a detached manner, the pressure release area of ​​the pressure release part 61 is enlarged, and the pressure release speed of the pressure release part 61 is improved.

[0113] 11 , in some embodiments, the cut groove 62 is annular. The annular cut groove 62 has a simple structure and is easy to form. When pressure is released, the pressure release portion 61 can quickly burst along the annular cut groove 62, thereby quickly opening the opening region 613.

[0114] 12 and 13, Fig. 12 is a partial enlarged view of part C of the pressure relief device 6 shown in Fig. 6, and Fig. 13 is a partial cross-sectional view of the pressure relief device 6 according to some other embodiments of the present application. Two or three stages of cut grooves 62 are provided in the pressure relief portion 61.

[0115] As shown in Figure 12, in an embodiment in which two stages of cut grooves 62 are installed in the pressure relief section 61, the two stages of cut grooves 62 are respectively a first stage of cut grooves 62 and a second stage of cut grooves 62, the second stage of cut grooves 62 are installed on the bottom surface of the first stage of cut grooves 62, the first stage of cut grooves 62 are closer to the first surface 611 than the second stage of cut grooves 62, and the second stage of cut grooves 62 are the one-stage of cut grooves 62 farthest from the first surface 611.

[0116] As shown in FIG. 13 , in an embodiment in which three stages of cut grooves 62 are installed in the pressure relief section 61, the three stages of cut grooves 62 are respectively a first stage of cut groove 62, a second stage of cut groove 62, and a third stage of cut groove 62, the second stage of cut groove 62 is installed on the bottom surface of the first stage of cut groove 62, and the first stage of cut groove 62 is closer to the first surface 611 than the second stage of cut groove 62, the third stage of cut groove 62 is installed on the bottom surface of the second stage of cut groove 62, and the second stage of cut groove 62 is closer to the first surface 611 than the third stage of cut groove 62, and the third stage of cut groove 62 is the one stage of cut groove 62 that is farthest from the first surface 611.

[0117] In some embodiments, referring to FIGS. 12 and 13, along the thickness direction Z, the outermost single-stage cut groove 62 is located on the first surface 611.

[0118] As can be seen, the outermost single-stage cut groove 62 is recessed along a direction from the first surface 611 toward the second surface 612 .

[0119] In this embodiment, the outermost single-stage cut groove 62 can be directly formed on the first surface 611, which simplifies the structure of the pressure relief device 6 and reduces the production cost.

[0120] 14 to 17, in some embodiments, Fig. 14 is a perspective view of a pressure relief device 6 according to some embodiments of the present application, Fig. 15 is a plan view of the pressure relief device 6 shown in Fig. 14, Fig. 16 is a partial enlarged view of portion D of the pressure relief device 6 shown in Fig. 14, and Fig. 17 is an E-E cross-sectional view of the pressure relief device 6 shown in Fig. 15. The pressure relief device 6 further includes at least one stage of sunken grooves 65, and the at least one stage of sunken grooves 65 and the multiple stages of cut grooves 62 are sequentially installed in the pressure relief portion 61 along the direction from the first surface 611 to the second surface 612. Here, the open region 613 is formed in the groove bottom wall 651 of the one stage of sunken groove 65 that is farthest from the first surface 611.

[0121] The pressure relief portion 61 may have one or more stages of sunken grooves 65. When the pressure relief portion 61 has multiple stages of sunken grooves 65, the multiple stages of sunken grooves 65 are arranged on the pressure relief portion 61 in order from the first surface 611 to the second surface 612, and the contour of the bottom surface of each stage of the sunken groove 65 becomes gradually smaller. The sunken grooves 65 may have various shapes, such as rectangular, circular, etc. The sunken grooves 65 on the pressure relief portion 61 may be formed by various methods, such as press forming, milling, etc.

[0122] At least one level of sunken grooves 65 and multiple levels of cut grooves 62 are sequentially formed in the pressure relief portion 61 along the direction from the first surface 611 to the second surface 612. When forming, all of the sunken grooves 65 may be formed in the pressure relief portion 61 first along the direction from the first surface 611 to the second surface 612, and then all of the cut grooves 62 may be formed. As can be understood, the level of cut grooves 62 closest to the first surface 611 is located at the bottom surface of the level of sunken grooves 65 farthest from the first surface 611. When only one level of sunken grooves 65 is formed in the pressure relief portion 61, the level of sunken grooves 65 is both the level of sunken grooves 65 closest to the first surface 611 and the level of sunken grooves 65 farthest from the first surface 611.

[0123] The groove bottom wall 651 of the one-stage sunken groove 65 farthest from the first surface 611 is the portion of the pressure relief portion 61 below the bottom surface of the one-stage sunken groove 65 farthest from the first surface 611, and after the one-stage sunken groove 65 farthest from the first surface 611 is formed in the pressure relief portion 61, the remaining portion of the pressure relief portion 61 in the area where the one-stage sunken groove 65 is installed is the groove bottom wall 651 of the one-stage sunken groove 65 farthest from the first surface 611. As shown in FIG. 17 , taking the installation of the one-stage sunken groove 65 in the pressure relief portion 61 as an example, the portion of the pressure relief portion 61 below the bottom surface of the sunken groove 65 is the groove bottom wall 651 of the one-stage sunken groove 65 farthest from the first surface 611.

[0124] The opening region 613 is formed in the groove bottom wall 651 of the first stage of the sunken groove 65 that is farthest from the first surface 611, and the opening region 613 is a portion of the groove bottom wall 651 of the first stage of the sunken groove 65 that is opened with the first stage of the cut groove 62 that is farthest from the first surface 611 as a boundary when pressure is released.

[0125] During molding, by first molding the sunken grooves 65 in the pressure relief portion 61, the region of the pressure relief portion 61 where the sunken grooves 65 are installed is made thinner overall, and the hardness of the remainder of this region is increased. Then, by molding the cut grooves 62 in the pressure relief portion 61, the hardness of the remainder of the pressure relief portion 61 in the region of the cut grooves 62 is further increased, improving long-term reliability, providing higher impact resistance, and reducing the probability of breakage due to impact from external force. Furthermore, because the opening region 613 is formed in the groove bottom wall 651 of the first stage of the sunken grooves 65 that is farthest from the first surface 611, the sunken grooves 65 can provide a retreat space when the opening region 613 is opening, and so even if the first surface 611 is blocked by an obstacle, the opening region 613 can still open to relieve pressure.

[0126] In some embodiments, still referring to Figures 14 to 17, the pressure relief device 6 includes a single-stage sunken groove 65, the sunken groove 65 is located on the first surface 611, and the single-stage cut groove 62 closest to the first surface 611 is located on the bottom surface of the sunken groove 65.

[0127] The pressure relief portion 61 is provided with a single-stage sunken groove 65, which is the single-stage sunken groove 65 farthest from the first surface 611, and the open area 613 is formed on the groove bottom wall 651 of the single-stage sunken groove 65. The sunken groove 65 is provided on the first surface 611, and as can be seen, the sunken groove 65 is recessed along the direction from the first surface 611 to the second surface 612.

[0128] In this embodiment, the pressure relief part 61 is provided with a single-stage sunken groove 65, which simplifies the molding, improves production efficiency, and reduces production costs.

[0129] 18 to 21, in some embodiments, Fig. 18 is a perspective view of a pressure relief device 6 according to further some embodiments of the present application, Fig. 19 is a plan view of the pressure relief device 6 shown in Fig. 18, Fig. 20 is a partial enlarged view of portion F of the pressure relief device 6 shown in Fig. 18, and Fig. 21 is a cross-sectional view taken along line G-G of the pressure relief device 6 shown in Fig. 19. The pressure relief device 6 includes a plurality of stages of sunken grooves 65, and the plurality of stages of sunken grooves 65 are sequentially installed in the pressure relief section 61 along the direction from the first surface 611 to the second surface 612, and of two adjacent stages of sunken grooves 65, the stage of sunken groove 65 farther from the first surface 611 is installed on the bottom surface of the stage of sunken groove 65 closer to the first surface 611. Here, along the thickness direction Z, the outermost single-stage sunken groove 65 is located on the first surface 611, and the single-stage cut groove 62 closest to the first surface 611 is located on the bottom surface of the single-stage sunken groove 65 farthest from the first surface 611.

[0130] The pressure relief portion 61 may have two, three, four, or five stages of sunken grooves 65. The outermost stage of the sunken grooves 65 is recessed in a direction from the first surface 611 toward the second surface 612. As shown in FIG. 21 , taking the pressure relief portion 61 having two stages of sunken grooves 65 as an example, the first stage of the sunken grooves 65 (the outermost stage of the sunken grooves 65) is located on the first surface 611, and the second stage of the sunken grooves 65 (the stage of the sunken grooves 65 furthest from the first surface 611) is located on the bottom surface of the first stage of the sunken grooves 65. An open region 613 is formed on the groove bottom wall 651 of the second stage of the sunken grooves 65. The stage of the sunken grooves 65 furthest from the first surface 611 is the innermost stage of the sunken grooves 65.

[0131] When the pressure relief portion 61 is provided with a plurality of stages of sunken grooves 65, the pressure relief portion 61 may be provided with a single stage of cut grooves 62 or may be provided with a plurality of stages of cut grooves 62.

[0132] By providing the multi-stage sunken grooves 65 in the pressure relief portion 61, the forming depth of each stage of the sunken grooves 65 can be made relatively shallow, reducing the forming force that the pressure relief portion 61 receives when forming each stage of the sunken grooves 65 and reducing the risk of cracks occurring in the pressure relief portion 61. When the multi-stage sunken grooves 65 are machined stage by stage along the direction from the first surface 611 to the second surface 612, the hardness of the remaining portion of the pressure relief portion 61 in the region where the sunken groove 65 is provided increases with each stage of the sunken groove 65 being machined, thereby further increasing the hardness of the remaining portion of the pressure relief portion 61 in the region of the cut groove 62. Note that, among the multi-stage sunken grooves 65, the outermost sunken grooves 65 have a larger outline size of the cross section (perpendicular to the thickness direction Z of the pressure relief portion 61), and the multi-stage sunken grooves 65 can provide more retraction space for opening the opening region 613.

[0133] In some embodiments, the recessed groove 65 is a rectangular groove or a circular groove.

[0134] If the sunken groove 65 is a rectangular groove, the cross section of the groove side surface of the sunken groove 65 will be rectangular. If the sunken groove 65 is a circular groove, the cross section of the groove side surface of the sunken groove 65 will be circular. Here, the cross section is perpendicular to the thickness direction Z of the pressure relief portion 61.

[0135] Illustratively, in FIGS. 14 to 21, the sunken grooves 65 are rectangular grooves.

[0136] In this embodiment, the sunken groove 65 is a rectangular groove or a circular groove, and the structure of the sunken groove 65 is simple, easy to form, and can provide more escape space for the opening of the opening region 613.

[0137] In some embodiments, with continued reference to FIGS. 17 and 21, a flange 6111 is disposed on the first surface 611, and the flange 6111 surrounds a single-stage sunken groove 65 disposed on the first surface 611.

[0138] The flange 6111 is a closed structure extending along a closed locus, and may be a circular ring or rectangular ring structure. If the sunken groove 65 is a rectangular groove, the flange 6111 may be set as a corresponding rectangular ring structure, and if the sunken groove 65 is a circular groove, the flange 6111 may be set as a corresponding circular ring structure.

[0139] Illustratively, the groove side of a one-stage sunken groove 65 installed on the first surface 611 intersects with the first surface 611 at an edge line, the edge line is located within the flange 6111, and there is a distance between the edge line and the inner surface of the flange 6111.

[0140] The flange 6111 reinforces the pressure relief portion 61 and can improve the deformation resistance of the pressure relief area of ​​the pressure relief portion 61. Note that the provision of the flange 6111 is useful for attaching a protective member, thereby protecting the opening area 613.

[0141] 17 and 21, in some embodiments, a portion of the pressure relief portion 61 protrudes from the second surface 612 in a direction away from the first surface 611 to form a protrusion 6121. The protrusion 6121 includes a groove bottom wall 651 and a reinforcing portion 6121a, which is connected to the second surface 612 and surrounds the periphery of the groove bottom wall 651.

[0142] The outer contour shape of the convex portion 6121 may be various shapes, for example, circular, rectangular, etc. When the sunken grooves 65 are formed in the pressure relief portion 61 by press molding, a portion of the pressure relief portion 61 may be protruded in a direction from the first surface 611 to the second surface 612 to form the convex portion 6121 protruding from the second surface 612. The one-stage sunken groove 65 farthest from the first surface 611 is located within the convex portion 6121, i.e., the bottom surface of the one-stage sunken groove 65 farthest from the first surface 611 is farther from the first surface 611 than the second surface 612, so that the reinforcing portion 6121a is disposed surrounding the one-stage sunken groove 65 farthest from the first surface 611.

[0143] In an embodiment in which the pressure relief portion 61 has the notched groove 64 , the notched groove 64 may be provided on the surface of the protrusion 6121 that is away from the second surface 612 .

[0144] In an embodiment in which a flange 6111 is installed on the pressure relief portion 61, the inner surface of the flange 6111 may be projected along the thickness direction Z of the pressure relief portion 61 to form a convex portion 6121, which further improves the deformation resistance of the pressure relief area of ​​the pressure relief portion 61.

[0145] In this embodiment, by connecting the reinforcing portion 6121a to the second surface 612, a reinforcing effect can be achieved on the groove bottom wall 651, improving the deformation resistance of the groove bottom wall 651 and reducing the risk of damage to the position where the notch groove 62 on the groove bottom wall 651 is installed due to force.

[0146] In some embodiments, and still referring to FIGS. 17 and 21, second surface 612 may include a recess 6122 formed therein, the recess 6122 surrounding protrusion 6121 .

[0147] The groove 6122 is a closed structure extending along a closed locus, and the shape of the groove 6122 may be various shapes, for example, a circular ring, a rectangular ring, etc. If the outer contour of the protrusion 6121 has a circular structure, the groove 6122 may be set in a corresponding circular ring shape, and if the outer contour of the protrusion 6121 has a rectangular structure, the groove 6122 may be set in a corresponding rectangular ring shape.

[0148] By providing the recessed grooves 6122, the pressure relief portion 61 can absorb the energy that is transmitted to the protruding portions 6121 when the pressure relief portion 61 receives force, and even if the pressure relief portion 61 is deformed, the deformation is unlikely to be transmitted to the area where the cut grooves 62 are provided.

[0149] In some embodiments, still referring to Figures 17 and 21, the height that the convex portion 6121 protrudes from the second surface 612 along the thickness direction Z is H1, and the distance between the first surface 611 and the second surface 612 is H2, where H1 ≥ H2.

[0150] The height that the convex portion 6121 protrudes from the second surface 612 along the thickness direction Z is the distance between the surface of the convex portion 6121 that faces away from the second surface 612 and the second surface 612, and the distance between the first surface 611 and the second surface 612 is the thickness of the pressure relief portion 61.

[0151] In this embodiment, H1≧H2 is satisfied, and therefore the height that the convex portion 6121 projects from the second surface 612 is large, and the reinforcing effect of the reinforcing portion 6121a on the groove bottom wall 651 is enhanced.

[0152] In some embodiments, of two adjacent cut grooves 62, the maximum width of the cut groove 62 that is farther from the first surface 611 is smaller than the minimum width of the cut groove 62 that is closer to the first surface 611.

[0153] Of two adjacent stages of cut grooves 62 in the thickness direction Z of the pressure relief portion 61, the maximum width of the stage of cut grooves 62 farther from the first surface 611 is smaller than the minimum width of the stage of cut grooves 62 closer to the first surface 611; that is, the widths of the multiple stages of cut grooves 62 gradually decrease in the direction from the first surface 611 to the second surface 612. The maximum width of the stage of cut grooves 62 farther from the first surface 611 does not restrict the width of the stage of cut grooves 62 farther from the first surface 611 from changing gradually; if the width of the stage of cut grooves 62 farther from the first surface 611 does not change along the thickness direction Z of the pressure relief portion 61, the width of the stage of cut grooves 62 farther from the first surface 611 may be referred to as the maximum width. The minimum width of the one-stage cut groove 62 close to the first surface 611 does not restrict the width of the one-stage cut groove 62 close to the first surface 611 of two adjacent cut grooves 62 from gradually changing, and if the width of the one-stage cut groove 62 close to the first surface 611 does not change along the thickness direction Z of the pressure relief portion 61, the width of the one-stage cut groove 62 close to the first surface 611 may be referred to as the minimum width.

[0154] It should be noted that in an embodiment in which the groove 62 includes a first groove segment 621, a second groove segment 622, and a third groove segment 623, for adjacent two groove stages, it is understandable that the maximum width of the first groove segment 621 of the groove 62 in the one stage far from the first surface 611 is smaller than the minimum width of the first groove segment 621 of the groove 62 in the one stage close to the first surface 611, the maximum width of the second groove segment 622 of the groove 62 in the one stage far from the first surface 611 is smaller than the minimum width of the second groove segment 622 of the groove 62 in the one stage close to the first surface 611, and the maximum width of the third groove segment 623 of the groove 62 in the one stage far from the first surface 611 is smaller than the minimum width of the third groove segment 623 of the groove 62 in the one stage close to the first surface 611.

[0155] In this embodiment, the width of the cut grooves 62 of each stage gradually decreases along the direction from the first surface 611 to the second surface 612, and when molding, the cut grooves 62 of each stage can be molded sequentially along the direction from the first surface 611 to the second surface 612, thereby facilitating the molding of the cut grooves 62 of each stage.

[0156] In some embodiments, referring to FIGS. 4 to 21, the pressure relief portion 61 is an end cap 3, and the end cap 3 is for closing the opening of the case 1.

[0157] The first surface 611 may be the outer surface of the end cap 3 and the second surface 612 may be the inner surface of the end cap 3, or the first surface 611 may be the inner surface of the end cap 3 and the second surface 612 may be the outer surface of the end cap 3. The outer surface of the end cap 3 is the surface of the end cap 3 that faces away from the case 1, and the inner surface of the end cap 3 is the surface of the end cap 3 that faces the case 1.

[0158] In this embodiment, the end cap 3 has a pressure relief function, and the pressure relief structure is formed by installing a notch 62 on the end cap 3, so that the pressure relief structure has higher stability and good long-term reliability.

[0159] In some embodiments, the first surface 611 is the surface of the end cap 3 that faces away from the case 1 .

[0160] 22 and 23, Fig. 22 is a perspective view of a pressure relief device 6 according to some other embodiments of the present application, and Fig. 23 is a partially enlarged view of a portion H of the pressure relief device 6 shown in Fig. 22. The pressure relief device 6 is a case 1, the interior of which forms an accommodation space, and the case 1 includes a plurality of walls which collectively define the accommodation space, and the accommodation space is for accommodating the electrode assembly 2, and at least one of the walls is a pressure relief portion 61.

[0161] In the case 1, one wall portion may be the pressure relief portion 61, or multiple wall portions may be the pressure relief portion 61. When multiple wall portions are the pressure relief portion 61, the case 1 has a corresponding multiple pressure relief portion 61. The first surface 611 of the pressure relief portion 61 may be the outer surface of the wall portion or the inner surface of the wall portion. The outer surface of the wall portion is the surface of the wall portion that faces away from the electrode assembly 2, and the inner surface of the wall portion is the surface of the wall portion that faces the electrode assembly 2.

[0162] In this embodiment, the pressure relief device 6 has a housing function for housing the electrode assembly 2 and also has a pressure relief function.

[0163] In some embodiments, still referring to FIG. 22, the case 1 includes a peripheral wall 66 and a bottom wall 67, the peripheral wall 66 is arranged to surround the edge of the bottom wall 67, the peripheral wall 66 and the bottom wall 67 jointly define the storage space, the end of the peripheral wall 66 facing the bottom wall 67 forms an opening, and the bottom wall 67 is the pressure relief portion 61.

[0164] The peripheral wall 66 is provided to surround the edge of the bottom wall 67, thereby enabling the case 1 to form an opening at the end opposite the bottom wall 67, and the end cap 3 is for covering the opening. The peripheral wall 66 and the bottom wall 67 are integrally molded.

[0165] In an embodiment in which the case 1 is a cylinder, the case 1 may have two walls, one wall being a bottom wall 67 and the other wall being a cylindrical peripheral wall 66. As shown in Figure 22, in an embodiment in which the case 1 is a rectangular parallelepiped, the case 1 may have five walls, one bottom wall 67 and four side walls, which are connected head to tail to form the peripheral wall 66.

[0166] In this embodiment, the bottom wall 67 is the pressure relief portion 61, so that the bottom wall 67 of the pressure relief device 6 has a pressure relief function and can easily release the pressure inside the accommodation space.

[0167] In some embodiments, the first surface 611 is an exterior surface of the wall.

[0168] As can be seen, in embodiments where the bottom wall 67 is the pressure relief portion 61 , the first surface 611 is the exterior surface of the bottom wall 67 .

[0169] When forming the recessed grooves 65 and the cut grooves 62 on the wall portion, the cut grooves 62 may be formed on the outside of the wall portion, which makes the forming easier.

[0170] An embodiment of the present application provides a battery cell 10 including a pressure relief device 6 according to any one of the above embodiments.

[0171] An embodiment of the present application provides a battery 100 including a battery cell 10 according to any one of the above embodiments.

[0172] An embodiment of the present application provides a power consuming device including the battery 100 according to any one of the above embodiments.

[0173] 14 to 17, an embodiment of the present application provides an end cap 3, which has a first surface 611 and a second surface 612 facing each other in a thickness direction Z thereof, and is provided with a one-stage sunken groove 65 and a two-stage cut groove 62, which are arranged in order from the first surface 611 to the second surface 612. An opening region 613 is provided on a groove bottom wall 651 of the sunken groove 65, and the cut grooves 62 are arranged along the edge of the opening region 613, and the opening region 613 is arranged so as to be open with the one-stage cut groove 62 farthest from the first surface 611 as a boundary. The cut groove 62 includes a first groove segment 621, a second groove segment 622, and a third groove segment 623, the first groove segment 621 and the second groove segment 622 being arranged opposite each other, and the first groove segment 621 and the second groove segment 622 both intersecting with the third groove segment 623, the first groove segment 621, the second groove segment 622, and the third groove segment 623 being arranged along the edge of the opening region 613, the first groove segment 621, the second groove segment 622, and the third groove segment 623 forming an H-shape, and the first groove segment 621, the second groove segment 622, and the third groove segment 623 jointly defining two opening regions 613, the two opening regions 613 being located on both sides of the third groove segment 623, respectively.

[0174] 22 and 23 , an embodiment of the present application further provides a case 1, which has a rectangular parallelepiped structure and has a bottom wall 67 on which a first-stage sunken groove 65 and a second-stage cut groove 62 are provided, the first-stage sunken groove 65 and the second-stage cut groove 62 being provided in order along a direction from a first surface 611 to a second surface 612. The sunken groove 65 is a rectangular groove, and is provided on the first surface 611. An opening region 613 is provided on a groove bottom wall 651 of the sunken groove 65, and the cut grooves 62 are provided along the edge of the opening region 613, and the opening region 613 is arranged so as to be open with the first-stage cut groove 62 farthest from the first surface 611 as a boundary. The cut groove 62 includes a first groove segment 621, a second groove segment 622, and a third groove segment 623, the first groove segment 621 and the second groove segment 622 being arranged opposite each other, and the first groove segment 621 and the second groove segment 622 both intersecting with the third groove segment 623, the first groove segment 621, the second groove segment 622, and the third groove segment 623 being arranged along the edges of the opening region 613, the first groove segment 621, the second groove segment 622, and the third groove segment 623 jointly defining two opening regions 613, the two opening regions 613 being respectively located on both sides of the third groove segment 623. A fourth groove segment 63 is provided in the pressure relief portion 61 , and the fourth groove segment 63 is located between the first groove segment 621 and the second groove segment 622 , and the fourth groove segment 63 intersects with the third groove segment 623 .

[0175] It should be noted that, where not inconsistent, the embodiments and features of the embodiments in the present application may be combined with each other.

[0176] The above examples are only intended to illustrate the technical solution of the present application and are not intended to limit the present application, and those skilled in the art may make various modifications and variations to the present application, and all modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall fall within the protection scope of the present application. [Explanation of symbols]

[0177] 1-Case 2-electrode assembly 21-Positive electrode tab 22-Negative electrode tab 3-End Cap 31-Positive electrode terminal 32-Negative electrode terminal 4-Current collecting parts 5-Insulating material 6-Pressure relief device 61-Pressure relief section 611-First Surface 6111-Flange 612-Second Surface 6121-Convex 6121a-Reinforcement part 6122-Groove 613-Opening Area 62-cut groove 621 - First groove segment 622 - Second groove segment 623 - Third groove segment 624 - 5th groove segment 63-Fourth groove segment 64-Notched groove 65-Sinkhole 651-Groove bottom wall 66-Peripheral wall 67-Bottom wall 10-Battery Cell 20-Enclosure 201-First part 202-Second part 100-battery 200-Controller 300-Motor 1000-Vehicle Z-thickness direction

Claims

1. A pressure relief device installed in a battery cell, a pressure relief portion having a first surface and a second surface disposed opposite to each other in a thickness direction; a plurality of stages of cut grooves that are sequentially installed in the pressure relief portion along a direction from the first surface to the second surface, wherein, of two adjacent stages of the cut grooves, one stage of the cut groove that is farther from the first surface includes a plurality of stages of cut grooves that are installed on a bottom surface of the one stage of the cut groove that is closer to the first surface, Here, the pressure relief portion has an open region, the cut grooves are installed along an edge of the open region, and the open region is arranged so as to be opened with the cut groove of one stage farthest from the first surface as a boundary, the cut groove includes a first groove segment, a second groove segment, and a third groove segment, the first groove segment and the second groove segment being disposed opposite each other, the first groove segment and the second groove segment both intersecting with the third groove segment, and the first groove segment, the second groove segment, and the third groove segment being disposed along an edge of the opening region; The cut groove further includes a fifth groove segment disposed opposite the third groove segment, the first groove segment and the second groove segment both intersect with the fifth groove segment, and the first groove segment, the second groove segment, the third groove segment and the fifth groove segment collectively define the opening area.

2. 2. The pressure relief device of claim 1, wherein a fourth groove segment is provided in the pressure relief section, the fourth groove segment is located between the first groove segment and the second groove segment, and the fourth groove segment intersects with the third groove segment.

3. 3. The pressure relief device of claim 2, wherein the fourth groove segment and the third groove segment intersect at an intersection position, and a distance from the intersection position to the first groove segment in an extension direction of the third groove segment is equal to a distance from the intersection position to the second groove segment.

4. The pressure relief device of claim 1 , wherein the first groove segment, the second groove segment, and the third groove segment collectively define at least one of the open areas.

5. The pressure relief device according to claim 1 , wherein the first groove segment, the second groove segment and the third groove segment define two of the opening regions located on either side of the third groove segment, respectively.

6. The pressure relief device according to claim 1 , wherein the cut groove is a non-closed groove extending along a non-closed path with no end connected to the beginning or end.

7. The pressure relief device according to claim 1 , wherein the notched groove is arc-shaped.

8. A pressure relief device installed in a battery cell, a pressure relief portion having a first surface and a second surface disposed opposite to each other in a thickness direction; a plurality of stages of cut grooves that are sequentially installed in the pressure relief portion along a direction from the first surface to the second surface, wherein, of two adjacent stages of the cut grooves, one stage of the cut groove that is farther from the first surface includes a plurality of stages of cut grooves that are installed on a bottom surface of the one stage of the cut groove that is closer to the first surface, Here, the pressure relief portion has an open region, the cut grooves are installed along an edge of the open region, and the open region is arranged so as to be opened with the cut groove of one stage farthest from the first surface as a boundary, The pressure relief device, wherein the cut groove is a closing groove extending along a closing locus whose ends are connected.

9. A pressure relief device installed in a battery cell, a pressure relief portion having a first surface and a second surface disposed opposite to each other in a thickness direction; a plurality of stages of cut grooves that are sequentially installed in the pressure relief portion along a direction from the first surface to the second surface, wherein, of two adjacent stages of the cut grooves, one stage of the cut groove that is farther from the first surface includes a plurality of stages of cut grooves that are installed on a bottom surface of the one stage of the cut groove that is closer to the first surface, Here, the pressure relief portion has an open region, the cut grooves are installed along an edge of the open region, and the open region is arranged so as to be opened with the cut groove of one stage farthest from the first surface as a boundary, The pressure relief device, wherein the cut groove is annular.

10. The pressure relief device according to claim 1 , wherein the cut grooves are provided in two or three stages in the pressure relief section.

11. The pressure relief device according to claim 1 , wherein the outermost cut grooves along the thickness direction are located on the first surface.

12. The pressure relief device is The pressure relief portion further includes at least one recessed groove, and the at least one recessed groove and the plurality of recessed grooves are sequentially arranged in the pressure relief portion along a direction from the first surface to the second surface; wherein the opening region is formed on a bottom wall of the sunken groove at one stage farthest from the first surface; The pressure relief device according to claim 1 , wherein a flange is provided on the first surface, the flange surrounding a periphery of the recessed groove of one stage provided on the first surface.

13. The pressure relief device according to claim 12, wherein the recessed groove is a rectangular groove or a circular groove.

14. The pressure relief device is The pressure relief portion further includes at least one recessed groove, and the at least one recessed groove and the plurality of recessed grooves are sequentially arranged in the pressure relief portion along a direction from the first surface to the second surface; wherein the opening region is formed on a bottom wall of the sunken groove at one stage farthest from the first surface; a part of the pressure relief portion protrudes from the second surface in a direction away from the first surface to form a convex portion; The pressure relief device according to claim 1 , wherein the protrusion includes the groove bottom wall and a reinforcing portion, the reinforcing portion being connected to the second surface and surrounding the periphery of the groove bottom wall.

15. The pressure relief device according to claim 14 , wherein the second surface is provided with a groove, the groove surrounding the protrusion.

16. 15. The pressure relief device of claim 14, wherein a height of the protrusion from the second surface along the thickness direction is H1, a distance between the first surface and the second surface is H2, and H1≧H2 is satisfied.

17. The pressure relief device according to claim 1, wherein the maximum width of the cut groove of one of the two adjacent stages farther from the first surface is smaller than the minimum width of the cut groove of one stage closer to the first surface.

18. The pressure relief device according to claim 1 , wherein the pressure relief portion is an end cap for closing an opening of a case.

19. 20. The pressure relief device of claim 18, wherein the first surface is a surface of an end cap facing away from the case.

20. 2. The pressure relief device of claim 1, wherein the pressure relief device is a case, the interior of the case forms an accommodation space, the case includes a plurality of wall portions, the plurality of wall portions collectively define the accommodation space, the accommodation space is for accommodating an electrode assembly, and at least one of the wall portions is the pressure relief portion.

21. The pressure relief device of claim 20, wherein the case includes a peripheral wall and a bottom wall, the peripheral wall is arranged to surround the edge of the bottom wall, the peripheral wall and the bottom wall jointly define the storage space, the end of the peripheral wall facing the bottom wall forms an opening, and the bottom wall is the pressure relief portion.

22. 21. The pressure relief device of claim 20, wherein the first surface is an exterior surface of a wall portion.

23. A battery cell comprising the pressure relief device according to any one of claims 1 to 22.

24. A battery comprising the battery cell of claim 23.

25. 25. A power consuming device comprising the battery of claim 24.

Images