Case assemblies, battery cells, batteries and power consuming devices

Abstract

The case assembly 400, the battery cell 10, the battery 100, and the power consumption device 1000 are provided. The case assembly 100 is used for the battery cell 10 and includes a case 1 and a separator 420. A pressure relief portion 430 is formed on the outer surface of the case 1. The separator 420 includes a bonding surface 421. The bonding surface 421 has a groove 422 formed therein. The bonding surface 421 is bonded to the outer surface of the case 1. At least a portion of the pressure relief portion 430 is accommodated in the groove 422.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to and benefits from a patent application with patent application number 202222808079.3, filed with the State Intellectual Property Office of China on October 25, 2022, the entire text of which is incorporated herein by reference.

[0002] The present application relates to the field of battery technology, and in particular to case assemblies, battery cells, batteries and power consuming devices. [Background technology]

[0003] Batteries are widely used in various power-consuming devices, such as music players, video cameras, pocket computers, and electric vehicles. During battery use, thermal runaway often occurs in battery cases due to the influence of the operating environment and the space limitations of the battery case. Thermal runaway often leads to an explosion, but the shock wave from the explosion is concentrated at the case opening because the structural strength of the case opening is relatively weaker than that of other parts of the case. However, other components are typically connected to the case opening, and the shock wave from the explosion can damage these components. Therefore, conventional techniques have been developed to provide a pressure relief function for the case by cutting notches in the case, thereby solving the problem of thermal runaway. However, due to the need for insulation performance, a separator must be coated on the case after cutting the case. However, this affects the flatness of the cut locations, often resulting in wrinkles in the separator. Summary of the Invention

[0004] The present application provides a case assembly, a battery cell, a battery, and a power consuming device that can solve the problem of wrinkling of the separator when cutting the battery case and covering the separator.

[0005] The case assembly used in the battery cell of the embodiment of the present application includes: A case in which a pressure relief part is installed, at least a part of which protrudes outward; The separator includes a bonding surface, a groove formed on the bonding surface, the bonding surface being bonded to the outer surface of the case, and at least a portion of the pressure release portion being accommodated in the groove.

[0006] In the case assembly of the embodiment of the present application, the cuts on the case can give the case a pressure relief function, and by providing a groove on the bonding surface of the separator, when the separator is bonded to the outer surface of the case, the pressure relief section formed after the cuts on the case can be partially accommodated in the groove, thereby reducing local height differences when the separator is bonded to the outer surface of the case, and further, providing a pressure relief section on the outer surface of the case can avoid the problem of wrinkles occurring when the separator and case are bonded together.

[0007] In some embodiments, the pressure relief portion is provided with a notch around its periphery.

[0008] In this way, the structural strength is low at the locations where the notches are provided around the pressure relief section, and in the event of thermal runaway of the case, some of the shock waves can escape through the notches, thereby reducing the size of the shock waves at the opening of the case and further dissipating pressure evenly across the outer surface of the case, preventing damage to other elements outside the case due to the shock waves.

[0009] In some embodiments, the pressure relief portion protrudes from the outer surface to a height a, and the groove has a depth t, where t≧a / 6.

[0010] By rationally setting the depth of the groove in this way, it is possible to avoid the problem of wrinkles occurring due to the presence of the pressure relief portion when the separator and the case are bonded together.

[0011] In some embodiments, the size of the groove is greater than the size of the pressure relief portion along the height direction of the case.

[0012] In this way, the separator can completely cover the pressure relief portion in the height direction of the case, and as a result, no wrinkles are generated due to the presence of the pressure relief portion when the separator and the case are bonded together.

[0013] In some embodiments, the case includes a side wall and a bottom wall connected to one end of the side wall, the pressure relief portion is formed on the outer peripheral surface of the side wall, and the separator is attached to the outer peripheral surface of the side wall.

[0014] In this way, by forming a pressure relief portion on the outer peripheral surface of the side wall relative to the bottom wall, the impact on other elements outside the case in the event of thermal runaway of the case can be reduced, and the separator can provide an insulating function to the outer peripheral surface of the case.

[0015] In some embodiments, the sidewall is a cylinder.

[0016] In this way, compared to other shapes, setting the side wall to a cylindrical shape is advantageous for bonding the separator to the side wall, and wrinkles are less likely to occur in the separator.

[0017] In some embodiments, the number of the pressure relief sections is multiple, and the multiple pressure relief sections are formed into at least one set of pressure relief section groups, each set of the pressure relief section groups includes multiple of the pressure relief sections, and the multiple pressure relief sections in each set of the pressure relief section groups are arranged at intervals along the circumferential direction of the side wall.

[0018] In this way, multiple pressure relief portions can protect other elements outside the case during thermal runaway of the case by providing better pressure relief capability than a single pressure relief portion.

[0019] In some embodiments, the separator includes a plurality of membrane layers disposed in a stack, and the groove is formed in at least one of the membrane layers.

[0020] In this way, by stacking and installing multiple membrane layers, the groove can be made deeper than with a single membrane layer, allowing more of the contour of the pressure relief portion to be accommodated in the groove.

[0021] In some embodiments, the plurality of film layers include adhesive layers and base layers, the adhesive layers and the base layers being arranged alternately, and one of the adhesive layers includes the bonding surface.

[0022] In this way, the separator can be attached to the case by the adhesive layer, and the base material layer is used to realize the insulating function. By alternately arranging the adhesive layer and the base material layer, the thickness of the separator can be increased and the groove can be set deeper, so that more of the contour of the pressure relief part can be accommodated in the groove.

[0023] In some embodiments, the membrane layer includes multiple membrane materials, which are cut and placed so that the membrane material of one of the adjacent membrane layers covers the cut location of the membrane material of the other membrane layer.

[0024] By arranging the membrane material in this manner, wrinkles are less likely to occur when the separator is attached to the outer surface of the case, and by arranging the membrane material in this manner, the amount of membrane material used can be reduced, thereby reducing usage costs.

[0025] A battery cell according to an embodiment of the present application includes the case assembly and the electrode assembly described in any one of the above embodiments, and the electrode assembly is housed in the case.

[0026] A battery according to an embodiment of the present application includes a housing and the battery cell according to the above embodiment, and the battery cell is housed within the housing.

[0027] The power consumption device according to the embodiment of the present application includes the battery according to the above embodiment.

[0028] The above description is merely a summary of the technical solution of the present application. In order to make the technical solution of the present application more clearly understandable, and to implement it in accordance with the content of the specification, and to make the above and other objectives, features and advantages of the present application more apparent, the following particularly cites specific embodiments of the present application for description. [Brief explanation of the drawings]

[0029] Various other benefits and advantages will become apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments. The drawings are intended only to illustrate the preferred embodiments and are not to be construed as limitations on the present application. The same reference numerals represent the same elements in all the drawings. In the drawings, [Figure 1] 1 is a structural schematic diagram of a power consumption device according to an embodiment of the present application; [Figure 2] 1 is an exploded schematic view of a battery according to an embodiment of the present application; [Figure 3] 1 is an exploded schematic view of a battery cell according to an embodiment of the present application; [Figure 4] FIG. 1 is an exploded schematic view of a case assembly according to an embodiment of the present application. [Figure 5] 1 is a structural schematic diagram of a case according to an embodiment of the present application; [Figure 6] 1 is a structural schematic diagram of a separator according to an embodiment of the present application; [Figure 7] 6 is a schematic enlarged view of a local area along the BB direction of the case of FIG. 5. FIG. [Figure 8] 6 is a schematic cross-sectional view of the case of FIG. 5 taken along the direction AA. [Figure 9] 1 is a structural schematic diagram of a separator according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0030] The following describes in detail the embodiments of the technical solution of the present application in conjunction with the drawings. The following embodiments are only used to more clearly explain the technical solution of the present application, and are merely examples, which do not limit the protection scope of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art of this application, and the terms used herein are only for describing specific embodiments and are not intended to limit this application. The terms "comprises" and "having" and any variations thereof in the specification and claims of this application and the description of the drawings above are intended to cover a non-exclusive "comprise."

[0032] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only for distinguishing different objects, and should not be understood as indicating or implying relative importance or as implicitly indicating the number, specific order, or hierarchical relationship of the indicated technical features. In the description of the embodiments of the present application, unless otherwise clearly and specifically limited, the meaning of "plurality" is two or more.

[0033] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. Appearances of this phrase in various locations throughout the specification do not necessarily all refer to the same embodiment, nor are they mutually exclusive, independent, or alternative embodiments. Those skilled in the art can explicitly or implicitly understand that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments of this application, the term "and / or" is merely a relation that describes related objects and indicates that three relations may exist. For example, A and / or B may represent three cases: A alone, a combination of A and B, and B alone. In addition, the character " / " in this specification generally indicates that the related objects before and after are in an "or" relationship.

[0035] In describing the embodiments of the present application, the term "plurality" refers to two or more (including two); similarly, "sets" refers to two or more (including two sets); and "plurality" refers to two or more (including two).

[0036] In describing the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center," "longitudinal direction," "lateral direction," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial direction," "radial direction," and "circumferential direction" are orientations or positional relationships shown in the drawings, and are intended only to facilitate and simplify the description of the embodiments of the present application. They do not indicate or imply that the referred devices or elements must have a specific orientation or be configured and operated in a specific orientation, and therefore cannot be understood as limitations of the embodiments of the present application.

[0037] In the description of the embodiments of the present application, unless otherwise clearly defined or limited, the technical terms "attached," "connected," "connected," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific circumstances.

[0038] Currently, from the viewpoint of market development, the application of batteries is becoming more and more widespread, and with the diversification of usage scenarios and the refinement of battery internal components, more and more attention is being paid to the safety performance of batteries. However, batteries will generate a certain amount of heat during use, and especially in a relatively high temperature environment, the battery may go into thermal runaway, causing safety risks.

[0039] Furthermore, the inventors have discovered that by providing a pressure relief structure for the battery cell and using the pressure relief structure to release the pressure inside the battery cell, it is possible to reduce the risk of the battery cell exploding or catching fire, or to reduce the adverse effects of a battery cell explosion or catching fire. Specifically, by making cuts on the outer surface of the case, the structural strength of the outer surface of the case can be reduced, and the pressure experienced by various parts of the case in the event of a battery cell explosion can be uniformed, thereby improving the safety of the battery cell.

[0040] Furthermore, the inventors have noted that due to the need for insulating performance, it is necessary to cover the case with a separator after making cuts in the case, and that after making cuts in the case, the cut material is pressed, thereby forming protrusions near the cuts, which often results in wrinkles when the separator and case are attached together.

[0041] In view of this, an embodiment of the present application provides a case assembly design, which may include a case and a separator, the separator may include an adhesive layer and a substrate layer, the adhesive layer may be used to adhere the case, and the substrate layer provides an insulating function for the case.

[0042] In such a case assembly, by creating grooves in the adhesive layer and the base material layer, protrusions on the case can be accommodated in the grooves, and further, wrinkles can be prevented from occurring when the separator and case are bonded together.

[0043] The case assembly of the embodiments of the present application may be widely used in battery cells, batteries, and power-consuming devices that use batteries.

[0044] The power consuming devices may be vehicles, mobile phones, portable devices, laptops, steamships, spacecraft, electric toys, power tools, etc. The vehicles may be fuel oil vehicles, gas vehicles, or new energy vehicles, and the new energy vehicles may be pure electric vehicles, hybrid vehicles, or range extender vehicles, etc. The spacecraft include airplanes, rockets, space shuttles, and spaceships, etc. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric steamship toys, and electric airplane toys, etc. The power tools include metal cutting power tools, polishing power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, hammer drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not particularly limit the above power consuming devices.

[0045] Referring to FIG. 1, FIG. 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application. For convenience of explanation, the following embodiment will be described using an example in which the power consumption device 1000 is a vehicle. A battery 100 is installed inside the vehicle, and the battery 100 may be installed at the bottom, head, or rear of the vehicle. The battery 100 may be used to power the vehicle, for example, as an operating power source for the vehicle.

[0046] The vehicle may further include a controller 200 and a motor 300, where the controller 200 is used to control the battery 100 to power the motor 300, for example for starting the vehicle, navigation and operating power consumption needs during driving.

[0047] In an embodiment of the present application, the battery 100 can be used not only as an operating power source for a vehicle, but also as a drive power source for the vehicle, replacing or partially replacing fuel oil or natural gas to provide drive power to the vehicle.

[0048] 2, which is an exploded schematic view of a battery 100 according to an embodiment of the present application. The battery 100 includes a battery cell 10 and a housing 20, and the housing 20 is used to house the battery cell 10.

[0049] In the embodiment of the present application, the battery cell 10 may include a lithium ion secondary battery, a lithium ion primary battery, a lithium-sulfur battery, a sodium-lithium ion battery, a sodium ion battery, or a magnesium ion battery, etc., but the embodiments of the present application are not limited thereto. The battery cell 10 may have a cylindrical, flat, rectangular, or other shape, etc., but the embodiments of the present application are not limited thereto. The battery cell 10 is generally divided into three types based on the packaging method: cylindrical battery cells, rectangular battery cells, and pouch battery cells, but the embodiments of the present application are not limited thereto.

[0050] The battery 100 referred to in the embodiments of this application is a single physical module that includes one or more battery cells 10 to provide higher voltage and capacity. For example, the battery 100 referred to in this application may include a battery module or a battery pack. The battery 100 generally includes a housing 20 for packaging one or more battery cells 10. The housing 20 can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells 10.

[0051] Here, the housing 20 is a member that houses the battery cells 10, and the housing 20 provides a housing 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, which are fitted together to define a housing space for 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 shape. The first portion 201 may have a hollow structure that is open on one side, and the second portion 202 may have a hollow structure that is open on one side, with the open side of the second portion 202 fitted over the open side of the first portion 201 to form the housing 20 having a housing space. The first part 201 may have a hollow structure open on one side, and the second part 202 may have a plate-like structure, and the second part 202 is 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 via a sealing element, which may be a sealing ring, a sealant, or the like.

[0052] When the battery 100 includes a plurality of battery cells 10, the plurality of battery cells 10 may be connected in series, parallel, or series-parallel, and a series-parallel connection means that the plurality of battery cells 10 may be connected in series or parallel. A battery module may be formed by first connecting the plurality of battery cells 10 in series, parallel, or series-parallel, and then the plurality of battery modules may be connected in series, parallel, or series-parallel to form a whole, 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 the whole made up of all of the battery cells 10 may then be housed in the housing 20.

[0053] In some embodiments, the battery 100 may further include busbar members, and electrical connection may be established between the multiple battery cells 10 via the busbar members to establish a series connection, a parallel connection, or a series-parallel connection of the multiple battery cells 10. The busbar members may be made of a metal conductor, such as copper, iron, aluminum, stainless steel, or an aluminum alloy.

[0054] 3, which is an exploded schematic view of a battery cell 10 according to an embodiment of the present application. The battery cell 10 includes a case 1, an electrode assembly 2, and an end cap 3.

[0055] The case 1 is a member for housing the electrode assembly 2. The case 1 may have a hollow structure with an opening at one end, or may have a hollow structure with openings at both opposing ends. The case 1 may have various shapes, such as a cylinder or a rectangular parallelepiped. The case 1 may be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0056] The electrode assembly 2 is a component in which 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 a positive electrode plate, a separator, and a negative electrode plate.

[0057] The end cap 3 is a member that seals the opening of the case 1 to separate the internal environment of the battery cell 10 from the external environment. The end cap 3 and the case 1 collectively define a sealed space for accommodating the electrode assembly 2, electrolyte, and other components. The end cap 3 may be welded to the case 1 to seal the opening of the case 1. The shape of the end cap 3 may be adapted to the shape of the case 1. For example, if the case 1 has a rectangular parallelepiped structure, the end cap 3 may have a rectangular plate-like structure that fits the case 1. Alternatively, for example, if the case 1 has a cylindrical shape, the end cap 3 may have a circular plate-like structure that fits the case 1. The end cap 3 may also be made of various materials, such as copper, iron, aluminum, steel, or an aluminum alloy.

[0058] In an embodiment in which the case 1 is a hollow structure with an opening formed at one end, one end cap 3 may be installed correspondingly, and in an embodiment in which the case 1 is a hollow structure with openings formed at both ends, two end caps 3 may be installed correspondingly.

[0059] 2 and 4, Fig. 4 is an exploded schematic view of a case assembly 400 according to an embodiment of the present application. The case assembly 400 used for the battery cell 10 according to the embodiment of the present application includes a case 1 and a separator 420. The case 1 is provided with a pressure relief portion 430, at least a portion of which protrudes outward. The separator 420 includes a bonding surface 421, which has a groove 422 formed in it. The bonding surface 421 is bonded to the outer surface of the case 1, and at least a portion of the pressure relief portion 430 is accommodated in the groove 422.

[0060] Specifically, separator 420 may be a film that provides insulation to case 1, and may be made of polypropylene (PP) or polyethylene (PE). When attaching separator 420 to the outer surface of case 1, the entire integrally molded separator 420 may be directly attached to the outer surface of case 1, or separators 420 of different lengths may be attached to the outer surface of case 1 in sequence until the outer surface of case 1 is completely covered.

[0061] When separators 420 of different lengths are used, separator 420 may be first attached to a portion of the outer surface of case 1 that does not include pressure relief portion 430, and then attached to a portion of the outer surface of case 1 that does include pressure relief portion 430. Similarly, separator 420 may be first attached to a portion of the outer surface of case 1 that includes pressure relief portion 430, and then attached to a portion of the outer surface of case 1 that does not include pressure relief portion 430.

[0062] The outer surface of the case 1 is the main body portion extending along the height direction of the case 1. For example, if the case 1 is a cylinder, the height direction of the case 1 coincides with the axial direction. The outer surface of the case 1 may be the surface that comes into contact with the outside, and may be smooth or may have a certain degree of roughness. The outer surface of the case 1 may be used to attach the separator 420.

[0063] The pressure relief portion 430 may be formed on the outer surface of the case 1 and may be a portion having a height difference from the outer surface of the case 1. The pressure relief portion 430 may be formed by cutting a notch in the outer surface of the case 1. As can be understood, when cutting the outer surface of the case 1, the material near the notch may be pressed. Specifically, the pressure relief portion 430 is formed to protrude outward from the case, and the protruding height depends on the depth of the notch and the material properties of the case. This affects the flatness around the pressure relief portion 430, which affects the flatness when the separator 420 is attached to the outer surface of the case 1, i.e., causes wrinkles in the separator 420. Furthermore, the number of pressure relief portions 430 may be multiple, and the cross section of the pressure relief portion 430 may be fan-shaped, circular, rectangular, or the like.

[0064] The bonding surface 421 may be the surface where the separator 420 is bonded to the outer surface of the case 1, and the bonding surface 421 of the separator 420 may have a certain adhesive performance so that the separator 420 can be bonded to the outer surface of the case 1 without coming off.

[0065] In case assembly 400 according to an embodiment of the present application, the cuts on case 1 can give case 1 a pressure relief function, and by providing grooves 422 on bonding surface 421 of separator 420, when separator 420 is bonded to the outer surface of case 1, pressure relief portions 430 formed after the cuts are made in case 1 can be partially accommodated in grooves 422, thereby reducing local height differences when separator 420 is bonded to the outer surface of case 1. Furthermore, providing pressure relief portions 430 on the outer surface of case 1 can avoid the problem of wrinkles occurring when separator 420 and case 1 are bonded together.

[0066] Referring to FIG. 4, in some embodiments, the pressure relief portion 430 has a periphery cut out.

[0067] Specifically, the depth of the cuts may be reasonably set according to the thickness of the case 1, the number of cuts may be multiple, and the depth of the cuts may be greater than 0 mm and less than the thickness of the case 1. For example, the thickness of the case 1 may be 2 mm, and the depth of the cuts may be 0.5 mm, 1 mm, 1.5 mm, etc. The embodiments of the present application do not specifically limit the depth of the cuts. It should also be noted that the numerical values ​​herein are merely illustrative and do not limit the embodiments of the present application. The formation of the cuts removes a portion of the material of the case 1, thereby reducing the local structural strength of the case 1, and also forms a pressure relief portion 430 on the outer surface of the case 1.

[0068] In this way, the structural strength is low at the locations where the notches are provided around the pressure relief portion 430, and in the event of thermal runaway of the case 1, some of the shock waves can escape through the notches, thereby reducing the size of the shock waves at the opening of the case 1 and further dissipating pressure evenly across the outer surface of the case 1, preventing damage to other elements outside the case 1 due to the shock waves.

[0069] 5, 6 and 7, Fig. 5 is a structural schematic diagram of case 1 according to an embodiment of the present application, Fig. 6 is a structural schematic diagram of separator 420 according to an embodiment of the present application, and Fig. 7 is a local enlarged schematic diagram of case 1 along direction BB in Fig. 5. In some embodiments, the protruding height of pressure relief portion 430 from the outer surface is a, and the depth of groove 422 is t, where t≧a / 6.

[0070] Specifically, the depth t of groove 422 may be a / 6, a / 2, a, etc. As can be understood, when the depth t of groove 422 is a / 6, pressure relief portion 430 may be partially accommodated within groove 422 in the depth direction of groove 422, and after separator 420 is attached to the outer surface of case 1, a height difference is formed between the portion of separator 420 that contacts pressure relief portion 430 and the portion that does not contact pressure relief portion 430. However, by reducing this height difference to a certain extent compared to when groove 422 is not provided, separator 420 can be positioned closer to the case. When the depth t of groove 422 is a, pressure relief portion 430 may be completely contained within groove 422 in the depth direction of groove 422. In this case, after separator 420 is attached to case 1, there is no difference in height between the points where separator 420 contacts pressure relief portion 430 and the points where separator 420 does not contact pressure relief portion 430, and separator 420 is less likely to wrinkle than when the depth t of groove 422 is a / 6.

[0071] Groove 422 may be recessed into bonding surface 421, away from the portion where the outer surface of case 1 contacts bonding surface 421, and length L2 and depth t of groove 422 may be set to match length L1 and height a of pressure relief portion 430 so that at least a portion of pressure relief portion 430 can be accommodated in groove 422. For example, length L1 and height a of pressure relief portion 430 may be set to 5 mm and 2 mm, respectively, and length L2 and depth t of groove 422 may be set to 4.5 mm and 1.5 mm, respectively, so that at least a portion of pressure relief portion 430 is accommodated in groove 422. It should be noted that the numerical values ​​herein are merely illustrative and are not intended to limit the embodiments of the present application.

[0072] In this way, by rationally setting the depth t of the groove 422, it is possible to avoid the problem of wrinkles occurring due to the presence of the pressure relief portion 430 when the separator 420 and the case 1 are bonded together.

[0073] 5 and 6, in some embodiments, the size of the groove 422 is larger than the size of the pressure relief portion 430 along the height direction of the case 1.

[0074] Specifically, assuming that case 1 is a cylinder, the height direction of case 1 is the axial direction of the cylinder. If the length L1 of pressure relief portion 430 is 5 mm, the length L2 of groove 422 may be 5.5 mm, 6 mm, 7 mm, etc. The embodiments of the present application do not specifically limit the length L2 of groove 422, and it should be noted that the numerical values ​​herein are merely illustrative and easy to understand, and do not limit the embodiments of the present application.

[0075] In this way, separator 420 can completely cover pressure relief portion 430 in the height direction of case 1, so that when separator 420 and case 1 are bonded together, wrinkles are not generated due to the presence of pressure relief portion 430.

[0076] 4, 5, and 8, Fig. 8 is a cross-sectional schematic view of the case 1 of Fig. 5 taken along the direction AA. In some embodiments, the case 1 includes a side wall 11 and a bottom wall 12 connected to one end of the side wall 11. A pressure relief portion 430 is formed on the outer peripheral surface 110 of the side wall 11, and a separator 420 is attached to the outer peripheral surface 110 of the side wall 11.

[0077] Specifically, the side wall 11 of the case 1 may be a main body portion extending along the height direction of the case 1. For example, if the case 1 is a cylinder, the height direction of the case 1 coincides with the axial direction, and the side wall 11 of the case 1 may be a main body portion extending along the axial direction of the case 1. Furthermore, the side wall 11 may be a cylindrical structure that goes around the axis of the case 1, and the cross section of the side wall 11 may be annular, and this cross section may be perpendicular to the axis of the case 1. The outer peripheral surface 110 of the side wall 11 may be a curved surface where the generatrix of this cylindrical structure is located.

[0078] The bottom wall 12 may be a main body extending along the width direction of the case 1. For example, if the case 1 is a cylinder, the width direction of the case 1 coincides with the radial direction, and the bottom wall 12 of the case 1 may be a main body extending along the radial direction of the case 1, or may be two end surfaces of the cylinder. End caps 3 may be attached to the bottom wall 12. The end caps 3 are used to seal the space of the case 1, but because the bottom wall 12 and the end caps 3 are not an integrated structure, in the event of thermal runaway of the case 1, pressure will concentrate at the connection between the end caps 3 and the bottom wall 12 and be released, thereby invalidating the connection between the end caps 3 and the bottom wall 12 and potentially damaging elements outside the case 1.

[0079] By making cuts in the side wall 11, pressure relief portions 430 can be formed on the outer circumferential surface 110 of the side wall 11. There may be multiple pressure relief portions 430, and the multiple pressure relief portions 430 may be distributed on the outer circumferential surface 110 of the side wall 11. At the same time, after making cuts in the outer circumferential surface 110 of the side wall 11, the structural strength of the cuts in the side wall 11 is reduced, so that when the case 1 experiences thermal runaway, some of the pressure is dispersed to the cuts in the side wall 11, thereby achieving the purpose of pressure relief.

[0080] The separator 420 may be completely attached to the outer peripheral surface 110 of the side wall 11 , and the separator 420 can provide an insulating function to the outer peripheral surface 110 of the side wall 11 .

[0081] In this way, by forming a pressure relief portion 430 on the outer peripheral surface 110 of the side wall 11 relative to the bottom wall 12, the impact on other elements outside the case 1 in the event of thermal runaway of the case 1 can be reduced, and the separator 420 can provide an insulating function to the outer peripheral surface 110 of the case 1.

[0082] 4 and 8, in some embodiments, the sidewall 11 is a cylinder.

[0083] Specifically, the cross section of the cylinder, ie, the side wall 11, is annular.

[0084] In this way, compared to other shapes, setting the side wall 11 to a cylindrical shape is advantageous for bonding the separator 420 and the side wall 11 together, and also makes the separator 420 less likely to wrinkle.

[0085] 4 and 5, in some embodiments, the number of pressure relief sections 430 is multiple, and the multiple pressure relief sections 430 form at least one set of pressure relief section 430 groups, each set of pressure relief section 430 groups includes multiple pressure relief sections 430, and the multiple pressure relief sections 430 in each set of pressure relief section 430 groups are arranged at intervals along the circumferential direction of the side wall 11.

[0086] Specifically, the number of pressure relief sections 430 may be two, three, four or more, for example, the number of pressure relief sections 430 may be ten, two sets of pressure relief sections 430 may be formed around the side wall 11, a first group of pressure relief sections 440 may be formed at a position close to the bottom wall 12 at one end of the case 1 on the side wall 11, the first group of pressure relief sections 440 may include five pressure relief sections 430, and these five pressure relief sections 430 may be uniformly arranged around the side wall 11 at regular intervals, or may be arranged around the side wall 11 at random intervals. Similarly, the second group of pressure relief portions 450 may be formed on the side wall 11 at a position close to the bottom wall 12 at the other end of the case 1, and the second group of pressure relief portions 450 may include five pressure relief portions 430, and these five pressure relief portions 430 may be uniformly arranged at regular intervals in the circumferential direction of the side wall 11, or may be arranged at random intervals in the circumferential direction of the side wall 11. It should be noted that the numbers used here are merely exemplary and easy to understand descriptions and do not limit the embodiments of the present application.

[0087] In this way, the multiple pressure relief parts 430 can provide better pressure relief capability than a single pressure relief part 430 when the case 1 experiences thermal runaway, thereby protecting other elements outside the case 1.

[0088] 4 and 6, in some embodiments, separator 420 includes multiple membrane layers disposed in a stack, with grooves 422 formed in at least one of the membrane layers.

[0089] Specifically, separator 420 may include two, three, four, or more membrane layers, for example, separator 420 may include four membrane layers, where the four membrane layers are stacked, and each membrane layer can provide a different function to separator 420. Groove 422 may be formed in first membrane layer 423, may be formed in first membrane layer 423 and second membrane layer 424, or may be formed in third membrane layer 425, where "formed" means that groove 422 penetrates through the membrane layers. As can be seen, when separator 420 has four layers, groove 422 can penetrate at least three film layers. Compared to when groove 422 penetrates one film layer, when groove 422 penetrates three film layers, groove 422 is deeper and pressure relief portion 430 can be completely accommodated within groove 422, thereby reducing or approaching zero the height difference when separator 420 is attached to side wall 11. However, groove 422 cannot penetrate the fourth film layer 426 so as not to affect the insulating performance of separator 420.

[0090] In this way, by stacking multiple membrane layers, the groove 422 can be made deeper than a single membrane layer, allowing more of the contour of the pressure relief portion 430 to be accommodated in the groove 422.

[0091] Referring to FIG. 6, in some embodiments, the multiple film layers include adhesive layers and substrate layers, which are arranged alternately, and one of the adhesive layers includes a bonding surface 421.

[0092] Specifically, the adhesive layer may be a membrane layer for bonding the separator 420 to the outer surface of the case 1, or the adhesive layer may be used to further bond the two substrate layers together, or the substrate layer may be a membrane layer for providing insulating properties to the separator 420. The alternating arrangement means that the number of substrate layers corresponds to the number of adhesive layers, and different substrate layers are connected by adhesive layers. For example, in a separator 420 having four membrane layers, the first membrane layer 423 may be an adhesive layer for bonding the outer surface of the case 1 to bond the separator 420 to the case 1, the second membrane layer 424 may be a substrate layer for providing insulating properties to the separator 420, and the third membrane layer 425 may be an adhesive layer for bonding the second membrane layer 424 to the fourth membrane layer 426, which is used to provide insulating properties to the separator 420. Additionally, multiple film layers allow the grooves 422 to be deeper without affecting the insulating performance of the separator 420 itself.

[0093] In this way, the separator 420 can be attached to the case 1 by the adhesive layer, and the base material layer is used to realize the insulating function. By alternately arranging the adhesive layer and the base material layer, the thickness of the separator 420 can be increased and the groove 422 can be installed deeper, so that more of the contour of the pressure relief part 430 is accommodated in the groove 422.

[0094] 9, which is a structural schematic diagram of a separator 420 according to an embodiment of the present application. In some embodiments, the membrane layer includes multiple membrane materials, which are cut and installed, and between two adjacent membrane layers, the membrane material of one membrane layer covers the cut position of the membrane material of another membrane layer.

[0095] Specifically, one membrane layer may include two, three, four, or even more membranes, and "cutting" refers to having a certain gap between these membranes, and "covering" refers to the gap between the membranes of one membrane layer being covered by the membrane of another membrane layer. For example, one membrane layer may include three membranes, with a certain gap between the first membrane 427 and the second membrane 428 and a certain gap between the second membrane 428 and the third membrane 429, with the first membrane 427 and the third membrane 429 located on different sides of the second membrane 428. Similarly, another membrane layer may include two membranes, with a certain gap between the fourth membrane 4201 and the fifth membrane 4202, with the fourth membrane 4201 covering the gap between the first membrane 427 and the second membrane 428 and the fifth membrane 4202 covering the gap between the second membrane 428 and the third membrane 429. Such placement corresponds to having grooves 422 in the membrane material itself, without removing material from separator 420 after separator 420 is molded.

[0096] By arranging the membrane material in this manner, wrinkles are less likely to occur when the separator 420 is attached to the outer surface of the case 1, and by arranging the membrane material in this manner, the amount of membrane material used can be reduced, thereby reducing usage costs.

[0097] The battery cell 10 according to the embodiment of the present application includes the case assembly 400 according to any one of the above embodiments and the electrode assembly 2 , and the electrode assembly 2 is housed in the case 1 .

[0098] The battery 100 according to the embodiment of the present application includes a housing 20 and the battery cells 10 according to the above embodiment, and the battery cells 10 are housed in the housing 20 .

[0099] The power consumption device of the embodiment of the present application includes the battery 100 of the above embodiment.

[0100] Specifically, the power consuming device may be a device that uses any one of the batteries 100 described above.

[0101] In one specific embodiment, a case assembly 400 is provided. The case assembly 400 includes a case 1 and a separator 420 attached to the outer surface of the case 1. The case 1 can be notched to reduce the structural strength of the notched portion, thereby achieving the purpose of pressure relief and resolving the problem of thermal runaway of the battery cells 10. After the notches are made, a pressure relief portion 430 is formed on the outer surface of the case 1, and a groove 422 is opened in the separator 420, thereby resolving the problem of wrinkles occurring when the separator 420 is attached to the outer surface of the case 1.

[0102] Finally, it should be noted that the above examples are merely for illustrating the technical solutions of the present application and are not intended to limit the same. Although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that the technical solutions described in the above examples may still be modified, or some or all of the technical features therein may be replaced with equivalents. Such modifications or replacements do not cause the essence of the relevant technical solutions to deviate from the scope of the technical solutions of the examples of the present application, and all of these should be included in the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in the examples may be combined in any manner. The present application is not limited to the specific examples disclosed herein, but includes all technical solutions encompassed within the scope of the claims. [Explanation of symbols]

[0103] The symbols in the description of the invention are as follows: Power consumption device 1000, battery 100, controller 200, motor 300, battery cell 10, housing 20, first part 201, second part 202, case 1, electrode assembly 2, end cap 3, case assembly 400, separator 420, pressure relief part 430, bonding surface 421, groove 422, side wall 11, bottom wall 12, outer peripheral surface 110, first pressure relief part group 440, second pressure relief part group 450, first membrane layer 423, second membrane layer 424, third membrane layer 425, fourth membrane layer 426, first membrane material 427, second membrane material 428, third membrane material 429, fourth membrane material 4201, fifth membrane material 4202.

Claims

1. 1. A case assembly for use with a battery cell, comprising: A case in which a pressure relief part is installed, at least a part of which protrudes outward; a separator including a bonding surface, the bonding surface having a groove formed therein, the bonding surface being bonded to an outer surface of the case, and at least a portion of the pressure relief portion being accommodated in the groove.

2. The case assembly according to claim 1 , wherein a notch is provided around the pressure relief portion.

3. 2. The case assembly according to claim 1, wherein the maximum height of the pressure relief portion protruding from the outer surface is a, and the depth of the groove is t, where t≧a / 6.

4. The case assembly according to claim 1 , wherein the groove has a size greater than the pressure relief portion along the height direction of the case.

5. 2. The case assembly according to claim 1, wherein the case includes a side wall and a bottom wall connected to one end of the side wall, the pressure relief portion is formed on an outer peripheral surface of the side wall, and the separator is attached to the outer peripheral surface of the side wall.

6. 6. The case assembly of claim 5, wherein the side wall is a cylinder.

7. The case assembly according to claim 5, characterized in that the number of the pressure relief sections is multiple, and at least one set of pressure relief section groups is formed among the multiple pressure relief sections, each set of the pressure relief section groups includes multiple pressure relief sections, and the multiple pressure relief sections in each set of the pressure relief section groups are arranged at intervals along the circumferential direction of the side wall.

8. 2. The case assembly according to claim 1, wherein the separator includes a plurality of film layers, the plurality of film layers being stacked and disposed, and the groove being formed in at least one of the film layers.

9. 9. The case assembly according to claim 8, wherein the plurality of film layers include adhesive layers and base layers, the adhesive layers and the base layers being arranged alternately, and one of the adhesive layers includes the bonding surface.

10. 9. The case assembly according to claim 8, wherein the membrane layer includes a plurality of membrane materials, the plurality of membrane materials being cut and installed, and in two adjacent membrane layers, the membrane material of one of the membrane layers covers the cut position of the membrane material of another of the membrane layers.

11. A battery cell, A case assembly according to any one of claims 1 to 10; and an electrode assembly housed within the case.

12. A battery, The housing and A battery comprising: the battery cell of claim 11 housed within the housing.

13. A power consuming device comprising the battery of claim 12.

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