Battery monomer, battery and electric equipment

Abstract

The utility model discloses a single battery, a battery and electric equipment, the single battery comprises a shell, a breathable membrane assembly and a one-way valve, the shell is provided with a wall part, the wall part is provided with a first exhaust hole and a second exhaust hole which are arranged at an interval, and the first exhaust hole and the second exhaust hole are respectively communicated with the interior and the exterior of the shell; the breathable film assembly is arranged on the wall part and covers the second exhaust hole; the one-way valve is arranged on the wall part and covers the first exhaust hole. Through the arrangement, gas in the shell can be exhausted out of the shell in time, so that the air pressure in the shell is not too high, the risk of opening a valve in advance of the pressure relief mechanism is reduced, and the service life of the single battery can be greatly prolonged.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] As global energy and environmental problems continue to intensify, new energy is developing rapidly as one of the areas of sustainable development. Batteries are increasingly widely used as a new energy source, and they have high requirements for reliability and service life. During the use of battery cells during charging and discharging, the internal pressure of the battery cells will increase due to the generation of gas inside the battery cells. In order to ensure the safety of the battery cells, a pressure relief mechanism for releasing the internal pressure of the battery cells is generally provided on the outer shell of the battery cells, so that when the internal pressure or temperature of the battery cells reaches a threshold, the pressure relief mechanism can be actuated and release the pressure inside the battery cells. However, the pressure relief mechanism of the existing battery cells may actuate the pressure relief in advance during use, resulting in poor stability in the use of the battery cells, which is not conducive to improving the service life and reliability of the battery cells. The above statements are only used to provide background technical information related to the present application and do not necessarily constitute prior art. Utility Model Content

[0003] The main technical problem solved by the present application is to provide a battery cell, a battery and an electrical device, which can discharge the gas inside the battery cell shell to the outside of the shell in time, so that the gas pressure inside the battery cell shell will not be too high, reduce the risk of premature valve opening of the pressure relief mechanism, and greatly improve the life of the battery cell.

[0004] In order to solve the above technical problems, a technical solution adopted by the present application is: to provide a battery cell, the battery cell includes a shell, a breathable membrane assembly and a one-way valve, the shell has a wall portion, the wall portion has a first exhaust hole and a second exhaust hole arranged at intervals, the first exhaust hole and the second exhaust hole are connected to the inside of the shell and the outside of the shell respectively; the breathable membrane assembly is arranged on the wall portion, and the breathable membrane assembly covers the second exhaust hole; the one-way valve is arranged on the wall portion, and the one-way valve covers the first exhaust hole. Among them, the breathable membrane assembly includes a breathable membrane; the one-way valve includes a valve body and a valve core, the valve body has a valve cavity inside, and the valve body is provided with an air inlet and an air outlet, the air inlet is used to connect the valve cavity with the inside of the shell, and the air outlet is used to connect the valve cavity with the outside of the shell; the valve core is arranged in the valve cavity, the valve core is used to block the air inlet, and the valve core is configured to open the air inlet under the action of the gas inside the shell and release the gas inside the battery cell. Through this arrangement, the breathable membrane assembly and the one-way valve are arranged in parallel, and the two can exhaust at the same time to achieve a relatively large exhaust rate.

[0005] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the housing, and the inner surface is disposed toward the inside of the housing; the valve body is disposed on the outer surface, and at least a portion of the valve body protrudes from the outer surface; at least a portion of the breathable membrane assembly is disposed on the outer surface. In this way, the assembly of the breathable membrane assembly and the one-way valve can be facilitated.

[0006] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the housing, and the inner surface is disposed toward the inside of the housing; the valve body is disposed on the outer surface, and at least a portion of the valve body protrudes from the outer surface; and the breathable membrane assembly is disposed on the inner surface. In this way, the assembly of the breathable membrane assembly and the one-way valve can be facilitated.

[0007] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the housing, and the inner surface is disposed toward the inside of the housing; the valve body is disposed on the outer surface, and at least a portion of the valve body protrudes from the inner surface; and the breathable membrane assembly is disposed on the inner surface. In this way, the effect of the installation of the one-way valve on the height of the battery cell can be reduced.

[0008] In one embodiment, the wall portion has an outer surface and an inner surface disposed opposite to each other, the outer surface is disposed toward the outside of the housing, and the inner surface is disposed toward the inside of the housing; the valve body is disposed on the outer surface, and at least a portion of the valve body protrudes from the inner surface; at least a portion of the breathable membrane assembly is disposed on the outer surface. In this way, the effect of the installation of the one-way valve on the height of the battery cell can be reduced.

[0009] In one embodiment, the valve body includes a valve seat and a valve cover, the valve cover includes a cover top wall and a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the valve seat enclose a valve cavity, the valve seat is provided with an air inlet, and the valve cover is provided with an air outlet. In this way, the gas is discharged easily.

[0010] In one embodiment, the valve seat has a first through hole penetrating the valve seat, and the gas inlet is the first through hole. In this way, the gas is easily discharged.

[0011] In one embodiment, the cover side wall has a second through hole penetrating the cover side wall, and the gas outlet is the second through hole. In this way, the gas is easily discharged.

[0012] In one embodiment, the second through hole extends to the end of the cover side wall in a direction away from the cover top wall; in this way, the discharge of gas is facilitated.

[0013] In one embodiment, there are a plurality of second through holes, and the plurality of second through holes are spaced apart and distributed in the circumferential direction of the side wall. In this way, the discharge of gas is facilitated.

[0014] In one embodiment, a first guide column is protruded on one side of the cover top wall facing the valve seat, a third through hole penetrating the cover top wall and the first guide column is provided on the cover top wall, or a third through hole penetrating the cover top wall is provided on the cover top wall, and the gas outlet is the third through hole. In this way, the gas discharge is facilitated.

[0015] In one embodiment, the valve cover further comprises a flange wall, the cover side wall connects the cover top wall and the flange wall, the flange wall extends toward a side away from the valve cavity relative to the cover side wall, and the flange wall is connected to the valve seat. In this way, the assembly of the one-way valve is facilitated.

[0016] In one embodiment, a first recessed groove is provided on the side of the valve seat facing the valve cover, which is recessed relative to the surface of the valve seat, and at least a portion of the flange wall is accommodated in the first recessed groove and connected to the valve seat. In this way, the connection strength can be improved and the installation height of the one-way valve can be reduced.

[0017] In one embodiment, the surface of the flange wall facing the cover top wall is flush with the surface of the valve seat facing the valve cover; or the surface of the flange wall facing the cover top wall is lower than the surface of the valve seat facing the valve cover. In this way, the installation height of the one-way valve can be reduced.

[0018] In one embodiment, the flange wall is welded to the valve seat, wherein, in the circumferential direction of the cover side wall, at least a portion of the first weld mark between the flange wall and the valve seat is staggered with the second through hole on the cover side wall. In this way, the damage to the valve core component caused by the high temperature of the welding process can be reduced.

[0019] In one embodiment, the outer circumferential surface of the valve seat is provided with a connecting protrusion, and the inner circumferential surface of the flange wall is provided with a receiving groove, and the connecting protrusion is received in the receiving groove and connected to the flange wall. In this way, the connection strength can be improved and the installation height of the one-way valve can be reduced.

[0020] In one embodiment, the connecting protrusion is welded to the flange wall, wherein the flange wall has an upper surface and a lower surface disposed opposite to each other, the upper surface is disposed toward the top wall of the cover, and the second weld mark of the connecting protrusion and the flange wall is located on the lower surface of the flange wall. In this way, the damage to the valve core component caused by the high temperature of the welding process can be reduced.

[0021] In one embodiment, the valve body includes a valve cover, the valve cover includes a cover top wall, a cover side wall connected to the cover top wall, the cover top wall, the cover side wall and the wall portion enclose a valve cavity, the through hole section of the first exhaust hole is an air inlet, and an air outlet is provided on the cover side wall. In this way, the exhaust of gas is facilitated.

[0022] In one embodiment, a second recessed groove is provided on one side of the wall portion facing the outside of the housing, and the valve cover further comprises a flange wall, a cover side wall connects the cover top wall and the flange wall, the flange wall extends toward a side away from the valve cavity relative to the cover side wall, and at least a portion of the flange wall is accommodated in the second recessed groove and connected to the wall portion. In this way, the installation height of the one-way valve can be reduced.

[0023] In one embodiment, the valve body includes a valve seat and a valve cover, the valve seat includes a seat bottom wall and a seat side wall connected to the seat bottom wall; the valve cover is arranged at one end of the valve seat away from the seat bottom wall, the valve cover, the seat side wall and the seat bottom wall are enclosed to form a valve cavity, the valve seat is provided with a fourth through hole, and the air inlet is the fourth through hole. In this way, the gas is discharged easily.

[0024] In one embodiment, the valve cover has a fifth through hole penetrating the valve cover, and the gas outlet includes the fifth through hole. In this way, the gas discharge is facilitated.

[0025] In one embodiment, the valve cover is connected to the valve seat, and the gas outlet includes a first exhaust gap formed between the valve cover and the valve seat. In this way, the exhaust of gas is facilitated.

[0026] In one embodiment, the valve cover is connected to the wall portion, and the gas outlet includes a second exhaust gap formed between the valve cover and the wall portion. In this way, the gas is easily discharged.

[0027] In one embodiment, the valve body includes a valve seat, the valve seat includes a seat bottom wall and a seat side wall connected to the seat bottom wall, the seat bottom wall, the seat side wall and the wall portion enclose a valve cavity, a fourth through hole is provided on the valve seat, the air inlet is the fourth through hole, and the air outlet is the first exhaust hole. In this way, the installation height of the one-way valve can be reduced.

[0028] In one embodiment, the valve core includes an elastic member and a blocking member, wherein the elastic member is disposed in the valve cavity; the blocking member is movably disposed in the valve cavity, and the blocking member is used to block the air inlet under the action of the elastic member, and is used to open the air inlet under the action of the gas inside the housing. In this way, the discharge of gas can be facilitated.

[0029] In one embodiment, the valve body includes a valve cover, a first guide column is protruding from the side of the valve cover facing the valve cavity, and part of the elastic member is sleeved on the outside of the first guide column; in this way, the elastic member can be positioned and guided.

[0030] In one embodiment, the diameter of the first guide column is D1, and the inner diameter of the elastic member is D2, which satisfies 0 mm < D2 - D1 ≤ 5 mm. In this way, the assembly of the elastic member and the first guide column can be facilitated.

[0031] In one embodiment, a second guide column is protruding from one side of the blocking member facing the valve cover, and a portion of the elastic member is sleeved on the outer side of the second guide column. In this way, the elastic member can be positioned and guided.

[0032] In one embodiment, the diameter of the second guide column is D3, and the inner diameter of the elastic member is D2, which satisfies 0mm<D3-D1≤5mm. In this way, the assembly of the elastic member and the second guide column can be facilitated.

[0033] In one embodiment, in the axial direction of the elastic member, there is a gap between the end surface of the first guide column away from the valve cover and the end surface of the second guide column close to the valve cover; optionally, the height H1 of the gap satisfies 0mm

[0034] In one embodiment, in the axial direction of the valve cavity, the two ends of the elastic member respectively abut against the valve cover and the blocking member, the distance between the first abutting surface of the valve cover and the second abutting surface of the blocking member is L1, and the physical length of the elastic member is L2, satisfying that L1>L2, wherein the physical length of the elastic member is the physical length of the elastic member after the elastic member is completely compacted; optionally, L1-L2>0.5 mm. In this way, compression space of the elastic member can be reserved to drive the blocking member to block / open the air inlet.

[0035] In one embodiment, the elastic member is a spring, and the physical length of the elastic member L2=d1*n1+d2+d3, wherein d1 is the spring wire diameter, n1 is the maximum number of turns of the spring in the axial direction, d2 is the thickness of the outermost spring at one end of the spring, and d3 is the thickness of the outermost spring at the other end of the spring, and d2≤d1, d3≤d1.

[0036] In one embodiment, the outer circumferential surface of the blocking member is provided with a plurality of limiting protrusions, and the plurality of limiting protrusions are arranged at intervals along the circumference of the blocking member. In this way, the blocking member can be guided and limited to improve the stability of the movement of the blocking member.

[0037] In one embodiment, the plugging member includes a pressing portion and a sealing portion, and along the thickness direction of the wall portion, two ends of the elastic member abut against the valve cover and the pressing portion respectively, and the sealing portion is connected to a side of the pressing portion away from the valve cover, and the sealing portion is used to block the air inlet. In this way, it is beneficial to maintain the sealing performance of the housing.

[0038] In one embodiment, the sealing portion is made of EPDM, fluororubber or Teflon.

[0039] In one embodiment, the elastic member is made of steel, iron or aluminum.

[0040] ​In one embodiment, the valve cover includes a cover side wall, the cover side wall has a second through hole penetrating the cover side wall, the gas outlet is the second through hole, and along the axial direction of the valve cavity, the sealing interface between the valve core and the valve seat is higher than or flush with the bottom wall of the second through hole. In this way, the gas can be discharged easily.

[0041] In one embodiment, the first exhaust hole includes a through hole segment and a first hole segment, the through hole segment and the first hole segment are arranged along the thickness direction of the wall portion, the first hole segment is located on the side of the through hole segment away from the inside of the shell, the aperture of the first hole segment is larger than the aperture of the through hole segment, and the one-way valve is at least partially accommodated in the first hole segment. In this way, the assembly of the one-way valve can be facilitated.

[0042] In one embodiment, the first hole section includes a hole side surface arranged circumferentially, and the outer peripheral surface of the valve cover / valve seat of the one-way valve is welded to the hole side surface, which can improve the connection strength.

[0043] In one embodiment, a first step surface and a second step surface are provided on one side of the valve seat facing the valve cover, the first step surface is closer to the valve cover than the second step surface, and the outer peripheral surface of the second step is welded to the side surface of the hole. In this way, the assembly stability of the one-way valve can be improved.

[0044] In one embodiment, the hole side surface matches the outer peripheral surface of the valve cover / valve seat of the one-way valve, and the hole side wall surface and the outer peripheral surface of the valve cover / valve seat of the one-way valve are both arranged at an acute angle to the central axis of the first exhaust hole, which can improve the connection strength.

[0045] In one embodiment, a stress relief groove is provided around the third weld mark between the valve cover / valve seat and the wall; optionally, a first stress relief groove is provided on a surface of the valve seat / valve cover facing the outside of the housing; and / or a second stress relief groove is provided on a surface of the wall facing the outside of the housing. In this way, the stability of the connection can be improved.

[0046] In one embodiment, the breathable membrane assembly includes a breathable membrane and a connector, the connector is provided with a first breathable hole, the breathable membrane is provided on the connector and covers the first breathable hole, and the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged. This arrangement can improve the connection strength and reduce the risk of deformation of the breathable membrane.

[0047] In one embodiment, the connector has a first annular table surface that is recessed relative to the surface of the connector, the first annular table surface is arranged around the first vent hole, and the vent membrane is arranged on the first annular table surface. In this way, the installation height of the vent membrane assembly is reduced.

[0048] In one embodiment, the breathable membrane assembly further includes a backing member, which is disposed between the breathable membrane and the connecting member; the air permeability rate of the backing member is greater than the air permeability rate of the breathable membrane. By providing the backing member, support can be provided to the breathable membrane, reducing the risk of deformation of the breathable membrane.

[0049] In one embodiment, the connector further has a second annular table surface that is recessed relative to the surface of the connector, the second annular table surface is arranged around the first air hole, and the backing member is arranged on the second annular table surface. In this way, the installation height of the breathable membrane assembly can be reduced.

[0050] In one embodiment, the connecting piece is a metal piece, which can improve the connection strength between the connecting piece and other components.

[0051] In one embodiment, the breathable membrane is arranged on the side of the connector facing the inside of the housing, and the breathable membrane covers the first breathable hole. This arrangement can reduce the damage to the breathable membrane from the external environment.

[0052] In one embodiment, the connecting member is welded to the wall; optionally, a stress release groove is provided around the fourth weld mark between the connecting member and the wall; optionally, a third stress release groove is provided on the connecting member around the fourth weld mark between the connecting member and the wall; and / or a fourth stress release groove is provided on the wall around the fourth weld mark between the connecting member and the wall. In this way, the stability of the connection can be improved.

[0053] In one embodiment, the wall has a first sunken platform that is recessed relative to the surface of the wall, the first sunken platform is arranged around the second exhaust hole, and the breathable membrane assembly is at least partially located on the first sunken platform. In this way, the installation height of the breathable membrane assembly can be reduced.

[0054] In one embodiment, the battery cell further includes an insulating member, which is disposed on the side of the wall portion facing the inside of the housing; the insulating member is provided with a third exhaust hole and a fourth exhaust hole passing through the insulating member at intervals, the third exhaust hole is connected to the first exhaust hole on the wall portion, and the fourth exhaust hole is connected to the second exhaust hole on the wall portion. In this way, the exhaust of gas can be facilitated.

[0055] In one embodiment, the first exhaust hole is the injection hole of the battery cell. Or the first exhaust hole and the injection hole are arranged at intervals. In this way, the one-way valve is used to replace the sealing structure of the original injection hole, which can help simplify the structure of the battery cell.

[0056] In one embodiment, the housing includes a shell and an end cap, wherein a receiving cavity with an opening is formed inside the shell, and the receiving cavity is used to receive the electrode assembly; the end cap closes the opening; wherein the end cap is a wall; or the shell includes a wall; or the wall is a wall located at the top of the housing when the battery cell is in a placed state. In this way, the gas can be discharged easily.

[0057] In one embodiment, the first exhaust hole and the second exhaust hole are located on the same wall portion. In this way, the structure of the battery cell can be simplified.

[0058] In one embodiment, the battery cell further includes a pressure relief mechanism, which is disposed on the housing and is configured to actuate and release the internal pressure of the battery cell when the battery cell is in thermal runaway, and the actuation pressure of the pressure relief mechanism is greater than the opening pressure of the one-way valve. In this way, the safety of the battery can be improved.

[0059] In one embodiment, the wall has a pressure relief hole, which connects the inside of the shell with the outside of the shell, and is connected to the pressure relief mechanism; the diameter of the pressure relief hole is larger than the diameter of the first exhaust hole. In this way, the pressure relief capacity of the battery cell is improved.

[0060] In one embodiment, the exhaust rate of the one-way valve is lower than the exhaust rate of the pressure relief mechanism. In this way, the pressure relief capability of the battery cell is improved.

[0061] In one embodiment, the permeability rate of the breathable membrane is 3-10 ml / day. In this way, the internal pressure of the battery cell can be maintained.

[0062] In one embodiment, the opening pressure of the one-way valve is greater than or equal to 0.2 MPa; optionally, greater than or equal to 0.4 MPa. In this way, the internal pressure of the battery cell can be maintained.

[0063] In order to solve the above technical problems, another technical solution adopted by the present application is to provide a battery, the battery comprising the above battery monomer. The battery has at least the same advantages as the battery monomer.

[0064] In order to solve the above technical problems, another technical solution adopted by the present application is to provide an electric device, which includes the above battery. The electric device has at least the same advantages as the battery.

[0065] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0067] Figure 1 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments;

[0068] Figure 2 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments;

[0069] Figure 3 is a schematic diagram of a partial exploded structure of a battery cell according to one or more embodiments;

[0070] Figure 4 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments;

[0071] Figure 5 is a front view of a one-way valve according to one or more embodiments;

[0072] Figure 6 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

[0073] Figure 7 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments;

[0074] Figure 8 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0075] Fig. 9 is a front view of a one-way valve according to one or more embodiments;

[0076] Fig.10 is a bottom view of a one-way valve according to one or more embodiments;

[0077] Fig.11 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

[0078] Fig.12 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments;

[0079] Fig.13 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0080] Fig.14 is a front view of a one-way valve according to one or more embodiments;

[0081] Fig.15 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments;

[0082] Fig.16 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0083] Fig.17 is a front view of a one-way valve according to one or more embodiments;

[0084] Fig.18 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments;

[0085] Fig.19 is a schematic diagram of a state of an elastic member according to one or more embodiments;

[0086] Fig. 20 is a schematic structural diagram of a blocking member of a one-way valve according to one or more embodiments;

[0087] Fig.21 is a schematic diagram of a cross-sectional structure of a wall portion according to one or more embodiments;

[0088] Fig. 22 is a schematic cross-sectional structure diagram of a breathable membrane assembly according to one or more embodiments;

[0089] Fig.23 is a schematic cross-sectional structure diagram of a breathable membrane assembly according to one or more embodiments;

[0090] Fig.24 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0091] Fig.25 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments;

[0092] Fig.26 It is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments.

[0093] Fig. 27 It is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments.

[0094] Fig.28 It is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments.

[0095] Fig.29 is a schematic diagram of an exploded structure of a battery according to one or more embodiments;

[0096] Fig.30 is a schematic diagram of the structure of a vehicle according to one or more embodiments.

[0097] In the attached figure:

[0098] 1000, vehicle; 300, motor; 200, controller; 100, battery; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, end cap; 21a, outer surface; 21b, inner surface; 211, second stress release groove; 291, first exhaust hole; 292, second exhaust hole; 22, housing; 23, electrode assembly; 24, insulating member; 293, third exhaust hole; 294, fourth exhaust hole; 25, electrode terminal; 280, through hole 281, first hole section; 30 one-way valve; 31, valve body; 311, valve seat; 3111, first through hole; 3112, first sink groove; 3113, connecting protrusion; 3114, fourth through hole; 3115, seat bottom wall; 3116, seat side wall; 311a, first stress release groove; 311b, first step surface; 311c, second step surface; 312, valve cover; 312a, protrusion; 3121, cover top wall; 31211, first guide column; 31212, third through hole ; 3122, cover side wall; 31221, second through hole; 31222, flange wall; 31222a, connection surface; 31222b, receiving groove; 31222c, upper surface; 31222d, lower surface; 3123, fifth through hole; 313, valve cavity; 313a, air inlet; 313b, air outlet; 313c, first exhaust gap; 32, valve core; 321, blocking member; 3211, sealing portion; 3212, pressing portion; 3212a, limiting protrusion; 3212 b, second guide column; 322, elastic member; 40, breathable membrane assembly; 41, breathable membrane; 42, metal member; 421, third stress release groove; 491, first breathable hole; 43, backing member; 50, shielding member; 501, third exhaust gap; 70, pressure relief mechanism; 701, pressure relief hole; T1, first annular table; T2, second annular table; T3, transition surface; S1, first sink; W1, first weld mark; W2, second weld mark; W3, third weld mark; W4, fourth weld mark. DETAILED DESCRIPTION

[0099] In order to make the purpose, technical solution and effect of the present application clearer and more specific, the following will describe the embodiments of the technical solution of the present application in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0100] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0101] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), similarly, "multiple groups" refers to more than two (including two groups), and "multiple pieces" refers to more than two (including two pieces), unless otherwise clearly and specifically defined.

[0102] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0103] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0104] Amounts, ratios and other numerical values ​​are presented herein in a range format. It should be understood that such a range format is for convenience and brevity and should be flexibly understood to include not only the values ​​explicitly specified as range limits, but also all individual values ​​or sub-ranges encompassed within the range, as if each value and sub-range were explicitly specified.

[0105] In the description of the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0106] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0107] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0108] Batteries are widely used in the field of new energy, mainly including electric vehicles, energy storage systems and renewable energy. In the field of electric vehicles, higher performance such as longer driving range and fast charging are gradually achieved. In terms of energy storage systems, batteries are widely used in large-scale and distributed energy storage. They can balance the load of the grid, store renewable energy such as solar and wind power, and release the stored energy during peak hours. In addition, small rechargeable batteries are also widely used in applications such as wearable devices, drones and smart homes.

[0109] As the battery cells are charged and discharged, some side reactions will produce gas. If the gas produced by the battery cells is not discharged in time, the internal pressure of the battery cells will increase. Excessive internal pressure will have a negative impact on the performance and appearance of the battery cells. For example, in severe cases, it will have a destructive effect on the performance and appearance of the battery cells, such as leakage, bulging, increased internal resistance of the battery cells, and shortened discharge time and cycle life. In addition, there are some abnormal operations of the battery cells during use, including overcharging, over-discharging, internal failures, etc. In this case, the chemical reaction inside the battery cells may be uncontrolled, accompanied by violent release of gas, and even cause thermal runaway of the battery cells. Thermal runaway of battery cells refers to a chain reaction phenomenon caused by various inducements. The large amount of heat and harmful gases emitted by thermal runaway can cause the battery cells to catch fire and explode.

[0110] In order to improve the safety of battery cells, a pressure relief mechanism is usually provided on the outer shell of the battery cell to release the internal pressure of the battery cell through the pressure relief mechanism, thereby effectively improving the safety of the battery cell. However, the instability of the internal pressure during the use of the battery cell may cause the pressure relief mechanism of the battery cell to be activated and release pressure in advance, resulting in poor stability in the use of the battery cell, which is not conducive to improving the service life and reliability of the battery cell.

[0111] Based on the above considerations, an embodiment of the present application provides a battery cell, on which an exhaust assembly is provided. The exhaust assembly can be used to exhaust the gas inside the battery cell in a timely manner to maintain a stable internal pressure of the battery cell.

[0112] Please refer to Figure 1 , Figure 1 FIG. 2 is a schematic diagram of the exploded structure of a battery cell according to one or more embodiments. A battery cell 20 is the smallest unit that constitutes a battery. Figure 1 The battery cell 20 includes an end cover 21, a shell 22, an electrode assembly 23 and other functional components.

[0113] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easy to deform when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals 25 can be provided on the end cap 21. The electrode terminal 25 can be used to electrically connect with the electrode assembly 23 for outputting or inputting the electric energy of the battery cell 20. Exemplarily, the battery cell 20 is provided with two electrode terminals 25, and the two electrode terminals 25 are both installed on the end cap 21, and the two electrode terminals 25 are respectively used to electrically connect with the two pole ears of the electrode assembly 23 with opposite polarities to realize the output or input of the positive and negative electrodes of the battery cell 20 respectively. In some embodiments, the end cap 21 may also be provided with a pressure relief mechanism 70 for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value. The material of the end cap 21 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this. In some embodiments, an insulating member 24 may also be provided on the inner side of the end cap 21, and the insulating member 24 may be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. Exemplarily, the insulating member may be plastic, rubber, etc.

[0114] The shell 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, the electrolyte and other components. The shell 22 and the end cap 21 can be independent components, and an opening can be set on the shell 22, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 21 at the opening. Without limitation, the end cap 21 and the shell 22 can also be integrated. Specifically, the end cap 21 and the shell 22 can form a common connection surface before other components are put into the shell, and when the interior of the shell 22 needs to be encapsulated, the end cap 21 covers the shell 22. The shell 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0115] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. One or more electrode assemblies 23 may be included in the housing 22. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute a lug. The positive electrode lug and the negative electrode lug may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery cell, the positive electrode active material and the negative electrode active material react with the electrolyte, and the lugs connect the electrode terminals to form a current loop.

[0116] Please refer to Figure 2 , Figure 2Schematic diagram of partial decomposition structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the present application discloses a battery cell 20, which includes a shell, a breathable membrane assembly 40 and a one-way valve 30, wherein the shell has a wall portion, and the wall portion has a first exhaust hole 291 and a second exhaust hole 292 arranged at intervals, wherein the first exhaust hole 291 and the second exhaust hole 292 respectively connect the inside of the shell with the outside of the shell; the breathable membrane assembly 40 is arranged on the wall portion, and the breathable membrane assembly 40 covers the second exhaust hole 292; the one-way valve 30 is arranged on the wall portion, and the one-way valve 30 covers the first exhaust hole 291. Among them, the breathable membrane assembly 40 includes a breathable membrane 41; the one-way valve 30 includes a valve body 31 and a valve core 32, the valve body 31 has a valve cavity 313 inside, the valve body 31 is provided with an air inlet 313a and an air outlet 313b, the air inlet 313a is used to connect the valve cavity 313 with the inside of the shell, and the air outlet 313b is used to connect the valve cavity 313 with the outside of the shell; the valve core 32 is arranged in the valve cavity 313, the valve core 32 is used to block the air inlet 313a, and the valve core 32 is configured to open the air inlet 313a under the action of the gas inside the shell, and release the gas inside the battery cell 20.

[0117] The first exhaust hole 291 connects the inside of the shell with the outside of the shell, and the second exhaust hole 292 also connects the inside of the shell with the outside of the shell, that is, the two are two independent holes that can exhaust gas at the same time to adjust the pressure inside the shell of the battery cell 20. The end cover 21 may be provided with one first exhaust hole 291 and one second exhaust hole 292, or the end cover 21 may be provided with multiple first exhaust holes 291 and multiple second exhaust holes 292. The battery cell 20 is configured so that the gas exhausted through the first exhaust hole 291 flows through the one-way valve 30, and the gas exhausted through the second exhaust hole 292 flows through the breathable membrane assembly 40. In other words, the gas can be discharged from the battery cell 20 through the first exhaust hole 291 and the second exhaust hole 292 at the same time. When the gas is discharged through the first exhaust hole 291, it flows through the one-way valve 30, and when the gas is discharged through the second exhaust hole 292, it flows through the breathable membrane assembly 40; or the one-way valve 30 and the breathable membrane assembly 40 are connected in parallel, that is, part of the gas is discharged only through the one-way valve 30, and the other part of the gas is discharged only through the breathable membrane assembly 40. When there are multiple first exhaust holes 291, each first exhaust hole 291 is equipped with a one-way valve 30; when there are multiple second exhaust holes 292, each second exhaust hole 292 is equipped with a breathable membrane assembly 40.

[0118] In this embodiment, the breathable membrane assembly 40 and the one-way valve 30 are arranged in parallel, and the two can exhaust at the same time to achieve a relatively large exhaust rate. When the gas flows through the exhaust assembly 90, it can flow through the one-way valve 30 and the breathable membrane assembly 40 in the exhaust assembly 90 respectively, that is, part of the gas only flows through the one-way valve 30 to be discharged, and the other part of the gas only flows through the breathable membrane assembly 40 to be discharged. Because the one-way valve 30 will only open for exhaust when the internal air pressure of the battery cell 20 reaches the valve opening pressure, it is also possible to select only one of the devices for exhaust. Specifically, when the internal air pressure of the battery cell 20 is low, the air is mainly exhausted through the breathable membrane assembly 40. At this time, the one-way valve 30 is in a closed state and does not exhaust. When the internal air pressure of the battery cell 20 is high, the one-way valve 30 opens the valve to exhaust. At this time, the breathable membrane assembly 40 can also exhaust at the same time. The provision of the breathable membrane assembly 40 enables the battery cell 20 to be in a vented state at all times, thereby reducing the problem of frequent opening of the one-way valve 30 caused by unstable air pressure inside the battery cell 20, reducing the risk of external water vapor intrusion, and improving the sealing of the battery cell 20 system; at the same time, when the air pressure is low, the gas can be discharged in time through the breathable membrane assembly 40, which is conducive to adapting to different air pressure environments.

[0119] In this embodiment, a one-way valve 30 and a breathable membrane assembly 40 are used simultaneously to discharge the gas inside the outer shell of the battery cell 20 to the outside of the outer shell. Therefore, when gas is generated inside the outer shell during normal use of the battery cell 20, it can be discharged to the outside of the outer shell through the one-way valve 30 and the breathable membrane assembly 40, so as to alleviate the phenomenon that the internal pressure of the battery cell 20 reaches the threshold value in advance due to the increase of the internal air pressure of the battery cell 20, reduce the risk of premature actuation of the pressure relief of the battery cell 20, and thus effectively improve the use stability of the battery cell 20, so as to improve the service life and use reliability of the battery cell 20.

[0120] According to some embodiments of the present application, the outer shell includes an end cover 21 and a shell 22, and the wall portion may be a wall of the end cover 21 or a wall of the shell 22. That is, the breathable membrane assembly 40 and the one-way valve 30 may be arranged on the end cover 21 or on the shell 22. In other words, the wall portion for mounting the breathable membrane assembly 40 and the one-way valve 30 may be the end cover 21 of the outer shell or a wall of the shell 22 of the outer shell. Exemplarily, the wall portion is the end cover 21. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the wall portion may also be a bottom wall of the shell 22 and the end cover 21 arranged opposite to each other, and the wall portion may also be a side wall of the shell 22 and the end cover 21 adjacent to and connected to each other. The following will take the wall portion as the wall of the end cover 21 as an example to illustrate the present application scheme, but this should not limit the present application.

[0121] According to some embodiments of the present application, the wall portion has an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a is disposed toward the outside of the shell, and the inner surface 21b is disposed toward the inside of the shell; the valve body 31 of the one-way valve 30 is disposed on the outer surface 21a, and at least part of the valve body 31 protrudes from the outer surface 21a; the breathable membrane assembly 40 is disposed on the inner surface 21b. The wall portion may be an end cap 21, such as Figure 2 As shown, the end cap 21 has an outer surface 21a and an inner surface 21b, the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a, and at least part of the valve body 31 protrudes from the outer surface 21a, that is, the one-way valve 30 can be arranged on the side of the end cap 21 facing the outside of the housing; the breathable membrane assembly 40 is arranged on the inner surface 21b, and the breathable membrane assembly 40 can be arranged between the end cap 21 and the insulating member 24. Through this arrangement, on the one hand, the assembly of the one-way valve 30 is facilitated, and on the other hand, the risk of the breathable membrane assembly 40 being damaged by the external environment is reduced.

[0122] According to some embodiments of the present application, the wall portion has an outer surface 21a and an inner surface 21b that are arranged opposite to each other, the outer surface 21a is arranged toward the outside of the shell, and the inner surface 21b is arranged toward the inside of the shell; the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a, and at least part of the valve body 31 protrudes from the outer surface 21a; at least part of the breathable membrane assembly 40 is arranged on the outer surface 21a. Among them, the wall portion can be an end cap 21. In this embodiment, the one-way valve 30 and the breathable membrane assembly 40 can be arranged on the side of the end cap 21 facing the outside of the shell to facilitate the assembly of the one-way valve 30 and the breathable membrane assembly 40.

[0123] According to some embodiments of the present application, the wall portion has an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a is disposed toward the outside of the shell, and the inner surface 21b is disposed toward the inside of the shell; the valve body 31 of the one-way valve 30 is disposed on the outer surface 21a, and at least a portion of the valve body 31 protrudes from the inner surface 21b; at least a portion of the breathable membrane assembly 40 is disposed on the outer surface 21a. The wall portion may be an end cap 21, such as Figure 3 As shown, Figure 3 Schematic diagram of partial decomposition structure of a battery cell according to one or more embodiments. The end cap 21 has an outer surface 21a and an inner surface 21b. The valve body 31 of the one-way valve 30 is arranged on the outer surface 21a, and at least part of the valve body 31 protrudes from the inner surface 21b, that is, the one-way valve 30 can be arranged on the side of the end cap 21 facing the inside of the shell; through this arrangement, the space occupied by the one-way valve 30 in the height direction of the battery cell 20 can be reduced. The breathable membrane assembly 40 is arranged on the side of the end cap 21 facing the outside of the shell, which is convenient for the assembly of the breathable membrane assembly 40.

[0124] According to some embodiments of the present application, the wall portion has an outer surface 21a and an inner surface 21b that are arranged opposite to each other, the outer surface 21a is arranged toward the outside of the shell, and the inner surface 21b is arranged toward the inside of the shell; the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a, and at least part of the valve body 31 protrudes from the inner surface 21b; the breathable membrane assembly 40 is arranged on the inner surface 21b. Among them, the wall portion can be an end cap 21. In this embodiment, the one-way valve 30 and the breathable membrane assembly 40 can be arranged on the side of the end cap 21 facing the inside of the shell, so as to reduce the height impact of the installation of the one-way valve 30 and the breathable membrane assembly 40 on the space occupied by the battery cell 20.

[0125] Please refer to Figure 4 , Figure 4 Schematic diagram of the cross-sectional structure of a one-way valve according to one or more embodiments. According to some embodiments of the present application, the one-way valve 30 includes a valve body 31 and a valve core 32, the valve body 31 has a valve cavity 313 inside, the valve body 31 is provided with an air inlet 313a and an air outlet 313b, the air inlet 313a is used to connect the valve cavity 313 with the inside of the shell, and the air outlet 313b is used to connect the valve cavity 313 with the outside of the shell; the valve core 32 is arranged in the valve cavity 313, the valve core 32 is used to block the air inlet 313a, and the valve core 32 is configured to open the air inlet 313a under the action of the gas inside the shell, and release the gas inside the battery cell 20.

[0126] Among them, the air inlet 313a is used to connect the valve cavity 313 and the interior of the shell, that is, the gas inside the shell can enter the valve cavity 313 through the air inlet 313a; the air outlet 313b is used to connect the valve cavity 313 and the outside of the shell, that is, the gas in the valve cavity 313 can be discharged to the outside of the shell through the air outlet 313b; through this arrangement, the gas inside the shell of the battery cell 20 can be discharged to the outside of the shell through the valve cavity 313.

[0127] Specifically, when the gas inside the battery cell 20 shell is discharged through the one-way valve 30, its discharge path is the inside of the battery cell 20 - the air inlet 313a - the valve cavity 313 - the air outlet 313b - the outside of the battery cell 20, and the entire exhaust path constitutes an exhaust channel; Figure 4 In the path from A to B shown in (b), A is the inner side of the shell, and B is the outer side of the shell. That is, the gas inside the shell of the battery cell 20 enters the valve cavity 313 from the air inlet 313a, flows through the valve cavity 313, and is discharged from the air outlet 313b to the outside of the shell of the battery cell 20.

[0128] The valve core 32 is used to block the air inlet 313a of the valve cavity 313, and is used to open the air inlet 313a under the action of the gas inside the shell. The valve core 32 blocks the air inlet 313a, which means that the gas is not allowed to enter the valve cavity 313. The valve core 32 can directly block the air inlet 313a, and the gas is not allowed to enter the valve cavity 313. In other embodiments, the flow path of the gas can also be blocked, that is, the gas can enter the valve cavity 313 through the air inlet 313a, but its flow path is blocked and cannot continue to flow to the air outlet 313b. When the valve core 32 blocks the air inlet 313a, the gas outside the shell cannot enter the inside of the shell, and the gas inside the shell cannot be discharged from the outside of the shell. When the pressure of the gas inside the shell reaches a certain threshold, the gas inside the shell can push the valve core 32 to open the air inlet 313a, so that the gas inside the shell can enter the valve cavity 313 and then be discharged from the outside of the shell through the air outlet 313b. At the same time, the valve core 32 is only allowed to be opened in one direction by applying pressure from one side inside the shell, allowing the gas to flow out, but cannot be reversely opened from the side outside the shell.

[0129] Optionally, the structure of the valve core 32 can be various, for example, Figure 4 In the figure, the valve core 32 may include an elastic member 322 and a sealing member 321, the elastic member 322 is arranged in the valve cavity 313, the sealing member 321 is movably arranged in the valve cavity 313, and the sealing member 321 is used to block the air inlet 313a under the action of the elastic member 322, and is used to open the air inlet 313a under the action of the gas inside the shell.

[0130] like Figure 4 As shown in Figure 4 (a) is a schematic diagram of the one-way valve in the closed state; Figure 4 (b) is a schematic diagram of the one-way valve in the open state. The elastic member 322 provides an elastic force F1 to the blocking member 321, and the blocking member 321 is pressed to block the air inlet 313a. When the force F2 of the gas inside the shell acting on the blocking member 321 is greater than the elastic force F1 of the elastic member 322, the gas inside the shell can overcome the elastic force of the elastic member 322 and push the blocking member 321 to open the air inlet 313a, so as to allow the gas inside the shell to enter the valve cavity 313 and then be discharged to the outside of the shell through the air outlet 313b. On the contrary, after the gas inside the shell is discharged and the force F2 of the gas inside the shell acting on the blocking member 321 is less than the elastic force F1 of the elastic member 322, the elastic member 322 can drive the blocking member 321 to reset to block the air inlet 313a.

[0131] In other words, when the air pressure inside the shell increases to a certain value P1, the force F2 applied by the air pressure to the lower surface of the sealing member 321 is greater than the spring compression force F1, and the sealing interface of the valve core 32 to the valve cavity 313 fails, and the gas inside the shell enters the valve cavity 313, passes through the channel in the valve cavity 313, and is discharged to the outside of the shell through the outlet 313b. As the gas inside the shell is discharged, the internal air pressure drops, and when the air pressure reaches a certain value P2, the valve core 32 is closed to achieve sealing. The valve core 32 can open and close the valve repeatedly to exhaust and close the valve, so that the air pressure inside the shell is maintained between P1-P2, thereby reducing the risk of the pressure relief mechanism opening the valve prematurely due to excessive air pressure inside the shell.

[0132] According to some embodiments of the present application, when the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a of the wall, and at least part of the valve body 31 protrudes from the outer surface 21a, that is, the one-way valve 30 is arranged on the side of the wall facing the outside of the shell, a variety of one-way valves 30 with different structures can be set.

[0133] Please refer to Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 5 is a front view of a one-way valve according to one or more embodiments; Figure 6 is a schematic diagram of an exploded structure of a one-way valve according to one or more embodiments; Figure 7 is a schematic cross-sectional structure diagram of a one-way valve according to one or more embodiments; Figure 8 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. In one embodiment, the valve body 31 includes a valve seat 311 and a valve cover 312. The valve cover 312 includes a cover top wall 3121 and a cover side wall 3122 connected to the cover top wall 3121. The cover top wall 3121, the cover side wall 3122 and the valve seat 311 enclose a valve cavity 313. The valve seat 311 is provided with an air inlet 313a, and the valve cover 312 is provided with an air outlet 313b. In this way, the gas is discharged easily.

[0134] In this embodiment, the valve body 31 of the one-way valve 30 is provided with a valve seat 311 and a valve cover 312. The one-way valve 30 with this structure is provided with the valve body 31 as two parts, so that it is convenient to assemble the valve core 32 into the valve cavity 313, which is helpful to reduce the difficulty of assembling the one-way valve 30.

[0135] According to some embodiments of the present application, the valve seat 311 has a first through hole 3111 penetrating the valve seat 311, and the air inlet 313a is the first through hole 3111, that is, the first through hole 3111 serves as the air inlet 313a of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0136] According to some embodiments of the present application, the cover sidewall 3122 has a second through hole 31221 penetrating the cover sidewall 3122, and the gas outlet 313b is the second through hole 31221, that is, the second through hole 31221 is used as the gas outlet 313b of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0137] According to some embodiments of the present application, along a direction away from the cover top wall 3121 , the second through hole 31221 extends to an end of the cover side wall 3122 .

[0138] like Figure 6 As shown, the direction away from the cover top wall 3121 is the direction from the cover top wall 3121 to the valve seat 311 (the X direction in the figure), and the second through hole 31221 is formed by removing part of the structure of the cover side wall 3122. Along the X direction, the cover side wall 3122 is directly hollowed out to the bottom end of the cover side wall 3122.

[0139] In one embodiment, along the axial direction of the valve cavity 313 (the Y direction in the figure), the sealing interface between the valve core 32 and the valve seat 311 is higher than or flush with the bottom wall of the second through hole 31221. In the X direction, the lower opening surface of the second through hole 31221 can be flush with the sealing surface between the blocking member 321 and the valve seat 311, that is, the sealing interface is higher than or flush with the bottom wall of the second through hole 31221. The so-called bottom wall of the second through hole 31221 refers to the lowest point of the second through hole 31221, such as Figure 6 At the position indicated by the middle arrow P, along the X direction, the lower opening surface of the second through hole 31221 is the bottom wall of the second through hole 31221. Through this arrangement, when the one-way valve 30 is opened for exhaust, that is, when the blocking member 321 opens the sealing interface, the electrolyte liquid brought out with the gas can be discharged outward in time, so that the electrolyte is not easy to accumulate on the outer edge of the blocking member 321, thereby effectively ensuring the sealing and repeated opening function of the one-way valve 30.

[0140] According to some embodiments of the present application, there are multiple second through holes 31221, and the multiple second through holes 31221 are spaced apart in the circumferential direction of the cover side wall 3122. Through this arrangement, when the one-way valve 30 is opened for exhaust, the gas can be exhausted more quickly, and the exhaust time can be shortened, that is, the time when the battery cell 20 shell is in an open state can be shortened, so as to reduce the invasion of external water vapor into the battery cell 20 system during the valve opening period.

[0141] Please refer to Figure 7According to some embodiments of the present application, a first guide column 31211 is protruded from the side of the cover top wall 3121 facing the valve cavity 313, and a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121 and the first guide column 31211, or a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121, and the air outlet 313b is the third through hole 31212.

[0142] Specifically, a first guide column 31211 is convexly provided on one side of the cover top wall 3121 facing the valve cavity 313, and a third through hole 31212 is provided on the cover top wall 3121 that penetrates the cover top wall 3121 and the first guide column 31211, and the gas outlet 313b is the third through hole 31212. That is, the third through hole 31212 is used as the gas outlet 313b of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell 20 to the outside.

[0143] Please continue to refer to Figure 5 , Figure 6 , Figure 7 and Figure 8 According to some embodiments of the present application, the valve cover 312 also includes a flange wall 31222, the cover side wall 3122 connects the cover top wall 3121 and the flange wall 31222, the flange wall 31222 extends toward a side away from the valve cavity 313 relative to the cover side wall 3122, and the flange wall 31222 is connected to the valve seat 311.

[0144] According to some embodiments of the present application, the valve cover 312 is connected to the valve seat 311. Specifically, a first recessed groove 3112 is provided on the side of the valve seat 311 facing the valve cover 312, and at least a portion of the flange wall 31222 is accommodated in the first recessed groove 3112 and connected to the valve seat 311.

[0145] In this embodiment, a first recess 3112 is provided on the side of the valve seat 311 facing the valve cover 312, and at least a portion of the flange wall 31222 is accommodated in the first recess 3112. The one-way valve 30 adopting such a structure can save the space occupied by the valve body 31 in the thickness direction of the end cover 21 on the one hand, and can improve the structural stability of the valve cover 312 assembled on the valve seat 311 on the other hand.

[0146] According to some embodiments of the present application, the flange wall 31222 is accommodated in the first sink 3112 and connected to the valve seat 311. The thickness of the flange wall 31222 is less than or equal to the depth of the first sink 3112, so that after the flange wall 31222 is connected to the valve seat 311, the surface of the flange wall 31222 facing the cover top wall 3121 is flush with the surface of the valve seat 311 facing the valve cover 312; or the surface of the flange wall 31222 facing the cover top wall 3121 is lower than the surface of the valve seat 311 facing the valve cover 312. Figure 7 and Figure 8 As shown, after the valve cover 312 is connected to the valve seat 311, the flange wall 31222 is flush with the surface of the valve seat 311. This arrangement can reduce the overall installation height of the one-way valve 30.

[0147] According to some embodiments of the present application, the material of the valve seat 311 may be a metal material, such as copper, iron, aluminum, steel or aluminum alloy. Similarly, the material of the valve cover 312 may also be a metal material, such as copper, iron, aluminum, steel or aluminum alloy. The valve seat 311 and the valve cover 312 may be made of the same material or different materials. The valve cover 312 and the valve seat 311 may be assembled by welding (such as laser welding); they may also be assembled by mechanical interference, but the static friction generated by the interference must be greater than the rebound force of the elastic member 322.

[0148] According to some embodiments of the present application, the flange wall 31222 is welded to the valve seat 311 ; wherein, in the circumferential direction of the cover side wall 3122 , at least a portion of the first weld mark W1 between the flange wall 31222 and the valve seat 311 is staggered with the second through hole 31221 on the cover side wall 3122 .

[0149] The flange wall 31222 is an annular component with a certain thickness, and the outer peripheral surface of the flange wall 31222 is used as a connecting surface 31222a to be welded to the groove wall surface of the first sink groove 3112. Further, the connecting surface 31222a of the flange wall 31222 can be set as an inclined surface, and the groove wall surface of the first sink groove 3112 can also be set as an inclined surface accordingly, so that the connecting surface 31222a of the flange wall 31222 fits with the groove wall surface of the first sink groove 3112, as shown in FIG. Figure 7 and Figure 8 As shown, the flange wall 31222 and the first sink 3112 may form an interlocking structure. In this way, the welding quality can be improved, and the strength and stability of the connection can be enhanced. Furthermore, the valve cover 312 and the valve seat 311 are preferably made of the same material to achieve better welding quality.

[0150] According to some embodiments of the present application, in the circumferential direction of the cover side wall 3122, at least a portion of the first weld mark W1 where the flange wall 31222 is welded to the valve seat 311 is staggered with the second through hole 31221. Figure 5As shown, welding can be performed at a position on the cover side wall 3122 where no second through hole 31221 is opened. There can be multiple first weld marks W1, and the multiple first weld marks W1 are distributed in the circumferential direction of the cover side wall 3122. The distribution of the first weld marks W1 can be staggered with the distribution of the second through holes 31221. In other words, multiple second through holes 31221 are spaced apart in the circumferential direction of the cover side wall 3122, and the position without openings between adjacent second through holes 31221 has a solid wall, and welding is performed at a place with a solid wall. The first weld mark W1 in this article expresses the welding site or welding position between the flange wall 31222 and the valve seat 311, and does not mean that there must be a welding mark in the actual product. Whether there is a mark is different from the welding process, and it should not be limited to the presence of a mark. In this way, the solid wall has a certain heat-blocking effect, which can protect the sealing part 321 of the valve core 32 and reduce the impact of high temperature during welding on the sealing part 321, so as to prevent the sealing part 321 from being deformed by heat, thereby causing failure of the sealing interface when the valve is not opened.

[0151] Please refer to Fig. 9 , Fig.10 , Fig.11 and Fig.12 , Fig. 9 is a front view of a one-way valve according to one or more embodiments, Fig.10 is a bottom view of a one-way valve according to one or more embodiments, Fig.11 is a schematic diagram of the exploded structure of a one-way valve according to one or more embodiments. Fig.12 Schematic diagram of the cross-sectional structure of a one-way valve according to one or more embodiments. According to some embodiments of the present application, the valve seat 311 is connected to the valve cover 312. Specifically, the valve cover 312 includes a flange wall 31222, and the valve seat 311 is connected to the flange wall 31222. In other words, the valve seat 311 is connected to the flange wall 31222 of the valve cover 312.

[0152] According to some embodiments of the present application, a connecting protrusion 3113 is convexly provided on the outer circumference of the valve seat 311 , and a receiving groove 31222b is provided on the inner circumference of the flange wall 31222 . The connecting protrusion 3113 is received in the receiving groove 31222b and connected to the flange wall 31222 .

[0153] There are multiple connecting protrusions 3113, and the multiple connecting protrusions 3113 are arranged at intervals along the circumference of the valve seat 311. There are multiple corresponding receiving grooves 31222b, and the number of connecting protrusions 3113 is the same as the number of receiving grooves 31222b; the shape of the connecting protrusion 3113 matches the shape of the receiving groove 31222b, so that the connecting protrusion 3113 can be accommodated in the receiving groove 31222b. With this arrangement, after the valve cover 312 is connected to the valve seat 311, the surface of the flange wall 31222 is flush with the surface of the valve seat 311. In this way, the valve seat 311 will be embedded in the valve cover 312, which can reduce the overall installation height of the one-way valve 30. Compare Figure 8 and Fig.12 , Figure 8 In the scheme, the valve cover 312 is connected to the valve seat 311, and its installation height is the thickness of the valve cover 312 superimposed on the thickness of the valve seat 311; Fig.12 In the scheme, the valve seat 311 is connected to the valve cover 312, the valve seat 311 is completely contained, and its installation height is the thickness of the valve cover 312; compared with the former, the installation height of this embodiment is lower, reducing the space occupancy rate.

[0154] According to some embodiments of the present application, the connecting protrusion 3113 is welded to the flange wall 31222. The flange wall 31222 has an upper surface 31222c and a lower surface 31222d that are arranged opposite to each other, and the upper surface 31222c is arranged toward the cover top wall 3121. The second weld mark W2 of the flange wall 31222 of the connecting protrusion 3113 and the cover side wall 3122 is located on the lower surface 31222d of the flange wall 31222. That is, the welding is performed from the lower side of the valve cover 312 and the valve seat 311, as shown in FIG. Fig.12 The second weld mark W2 shown in the figure is located on the side away from the valve cavity 313. In this way, the valve seat 311 and the flange wall 31222 have a certain heat blocking effect, which can protect the sealing member 321 of the valve core 32 and reduce the influence of the high temperature during welding on the sealing member 321, so as to prevent the sealing member 321 from being deformed by heat, thereby causing the sealing interface to fail when the valve is not opened.

[0155] Please refer to Fig.13 , Fig.13 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. In this embodiment, the one-way valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve cavity 313 inside, and the valve core 32 is arranged in the valve cavity 313. The valve body 31 includes a valve cover 312, and the valve cover 312 includes a cover top wall 3121 and a cover side wall 3122 connected to the cover top wall 3121. The cover top wall 3121, the cover side wall 3122 and the end cover 21 enclose the valve cavity 313. The end cover 21 is provided with an air inlet of the valve cavity 313 to connect the valve cavity 313 with the inside of the shell; the valve cover 312 is provided with an air outlet of the valve cavity 313 to connect the valve cavity 313 with the outside of the shell.

[0156] In this embodiment, the valve body 31 of the one-way valve 30 may only have a valve cover 312 without a valve seat 311, and the valve cover 312 may be directly connected to the end cover 21; or in other words, the end cover 21 may be used as the valve seat 311 of the valve body 31. In this way, the installation height of the one-way valve 30 can be reduced. Figure 8 , Fig.12 and Fig.13 , Figure 8 In the scheme, the valve cover 312 is connected to the valve seat 311, and its installation height is the thickness of the valve cover 312 superimposed on the thickness of the valve seat 311, and then superimposed on the thickness of the end cover 21; Fig.12 In the scheme, the valve seat 311 is connected to the valve cover 312, the valve seat 311 is completely contained, and its installation height is the thickness of the valve cover 312 plus the thickness of part of the end cover 21; Fig.13 In the scheme, the valve cover 312 can be embedded in the end cover 21, and its installation height can be the thickness of the end cover 21. Compared with the three, the installation height of this embodiment is lower, which reduces the space occupancy.

[0157] According to some embodiments of the present application, a first exhaust hole 291 is provided on the end cover 21, and the first exhaust hole 291 connects the interior of the shell with the valve cavity 313, and the air inlet of the valve cavity 313 is the first exhaust hole 291, that is, the first exhaust hole 291 is used as the air inlet of the valve cavity 313. The cover side wall 3122 has a second through hole 31221 penetrating the cover side wall 3122, and the air outlet of the valve cavity 313 is the second through hole 31221, that is, the second through hole 31221 is used as the air outlet of the valve cavity 313. This arrangement can facilitate the outward transmission of gas inside the battery cell. In other embodiments, the air outlet may also be located on the top wall of the cover, and may be a third through hole penetrating the top wall of the cover, see for details. Figure 7 As described above, I will not repeat them here.

[0158] According to some embodiments of the present application, a second groove (not shown in the figure) is provided on the side of the end cover 21 facing the outside of the shell, which is recessed relative to the outer surface 21a of the end cover 21. The valve cover 312 also includes a flange wall 31222. The cover side wall 3122 connects the cover top wall 3121 and the flange wall 31222. The flange wall 31222 extends relative to the cover side wall 3122 toward a side away from the valve cavity 313. At least a portion of the flange wall 31222 is accommodated in the second groove and is connected to the end cover 21.

[0159] In this embodiment, a second groove is provided on the side of the end cover 21 facing the outside of the shell, and at least a portion of the flange wall 31222 is accommodated in the second groove. The one-way valve 30 with this structure can save the space occupied by the valve body 31 in the thickness direction of the end cover 21.

[0160] According to some embodiments of the present application, the flanged wall 31222 is accommodated in the second sink and connected to the end cover 21. The thickness of the flanged wall 31222 is less than or equal to the depth of the second sink, so that after the flanged wall 31222 is connected to the end cover 21, the surface of the flanged wall 31222 facing the cover top wall 3121 is flush with the surface of the end cover 21 facing the outside of the shell; or the surface of the flanged wall 31222 facing the cover top wall 3121 is lower than the surface of the end cover 21 facing the outside of the shell. Fig.13 As shown, after the valve cover 312 is connected to the end cover 21, the flange wall 31222 is flush with the outer surface 21a of the end cover 21. This arrangement can reduce the installation height of the one-way valve 30.

[0161] According to some embodiments of the present application, the flange wall 31222 is welded to the end cover 21. Specifically, the flange wall 31222 is an annular component with a certain thickness, and the outer peripheral surface of the flange wall 31222 is used as a connecting surface 31222a to be welded to the groove wall surface of the second sink groove. Further, the connecting surface 31222a of the flange wall 31222 can be set as an inclined surface, and the groove wall surface of the second sink groove is also set as an inclined surface, so that the connecting surface 31222a of the flange wall 31222 fits with the groove wall surface of the second sink groove, such as Fig.13 As shown, the flange wall 31222 and the second sink groove may form an interlocking structure. In this way, the welding quality can be improved, and the strength and stability of the connection can be enhanced. Furthermore, it is preferred that the valve cover 312 and the end cover 21 are made of the same material to achieve better welding quality. For example, both are made of aluminum.

[0162] According to some embodiments of the present application, when the valve body 31 of the one-way valve 30 is disposed on the outer surface 21a of the wall, at least part of the valve body 31 protrudes from the inner surface 21b of the wall, that is, the one-way valve 30 is disposed on the side of the wall facing the inside of the shell, or the valve body 31 extends to the inside of the shell along the thickness direction of the end cover 21. A variety of one-way valves 30 with different structures can be provided.

[0163] Please refer to Fig.14 , Fig.15 and Fig.16 , Fig.14 is a front view of a one-way valve according to one or more embodiments, Fig.15 is a schematic diagram of the exploded structure of a one-way valve according to one or more embodiments. Fig.16Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the one-way valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve cavity 313 inside, and the valve core 32 is arranged in the valve cavity 313. The valve body 31 includes a valve seat 311 and a valve cover 312. The valve seat 311 includes a seat bottom wall 3115 and a seat side wall 3116 connected to the seat bottom wall 3115. The valve cover 312 is arranged at one end of the valve seat 311 away from the seat bottom wall 3115. The valve cover 312, the seat side wall 3116 and the seat bottom wall 3115 enclose a valve cavity 313. The valve seat 311 is provided with an air inlet of the valve cavity 313 to connect the valve cavity 313 with the interior of the shell.

[0164] In this embodiment, the valve body 31 of the one-way valve 30 is provided with a valve seat 311 and a valve cover 312. The one-way valve 30 with this structure is provided with the valve body 31 as two parts, so that it is convenient to assemble the valve core 32 into the valve cavity 313, which is helpful to reduce the difficulty of assembling the one-way valve 30.

[0165] Please continue to refer to Fig.14 , Fig.15 and Fig.16 According to some embodiments of the present application, the valve seat 311 has a fourth through hole 3114 penetrating the bottom wall 3115 of the seat, and the air inlet is the fourth through hole 3114, that is, the fourth through hole 3114 serves as the air inlet of the valve cavity 313. Of course, in other embodiments, the air inlet may also be provided on the outer circumferential surface of the portion of the valve body 31 extending into the shell. When the air inlet is provided on the outer circumferential surface of the portion of the valve body 31 extending into the shell, the setting direction of the valve core 32 will be changed accordingly, and the blocking member 321 is movably provided in the valve cavity 313 along the radial direction of the valve seat 311, so that the valve core blocks the air inlet.

[0166] Please continue to refer to Fig.14 , Fig.15 and Fig.16 According to some embodiments of the present application, the gas outlet may be directly opened on the valve cover 312, that is, the gas outlet is a channel provided on the valve cover 312. Specifically, the valve cover 312 has a fifth through hole 3123 penetrating the valve cover 312, and the gas outlet includes the fifth through hole 3123, that is, the fifth through hole 3123 is used as the gas outlet of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell to the outside.

[0167] The fifth through hole 3123 provided on the valve cover 312 may be one or more. Fig.14 , 15In the embodiment, three fifth through holes 3123 are provided on the valve cover 312. Of course, in other embodiments, the number of the fifth through holes 3123 provided on the valve cover 312 may be two, four, five or six. As an example, there are multiple fifth through holes 3123 provided on the valve cover 312, and the multiple fifth through holes 3123 are arranged at equal intervals. As an example, the multiple fifth through holes 3123 are arranged at equal intervals around the center of the valve cover 312, so that the gas can flow out more smoothly.

[0168] A fifth through hole 3123 is provided on the valve cover 312 of the valve body 31 to form an air outlet of the valve body 31, so that the valve cavity 313 of the valve body 31 can be connected with the outside of the shell through the fifth through hole 3123 provided on the valve cover 312. The valve body 31 with such a structure can reduce the interference effect of the air outlet on the connection between the valve cover 312 and the valve seat 311, which is conducive to reducing the difficulty of assembling the valve cover 312 and the valve seat 311.

[0169] Please continue to refer to Fig.16 According to some embodiments of the present application, a first guide column 31211 is convexly provided on one side of the valve cover 312 facing the valve cavity, and a third through hole ( Fig.16 Not shown, please refer to Figure 7 ), the gas outlet is the third through hole. That is, the third through hole is used as the gas outlet of the valve cavity 313. This arrangement can facilitate the transmission of gas inside the battery cell to the outside.

[0170] Please refer to Fig.17 , Fig.17 31 is a front view of a one-way valve according to one or more embodiments. According to some embodiments of the present application, the gas outlet may also be arranged between the valve cover 312 and the valve seat 311, that is, the gas outlet is a gap formed between the valve cover 312 and the valve seat 311. Specifically, the valve cover 312 is connected to the valve seat 311, and the gas outlet includes a first exhaust gap 313c formed between the valve cover 312 and the valve seat 311.

[0171] The outer circumferential surface of the valve cover 312 is provided with a plurality of convex portions 312a, which are arranged at intervals along the circumference of the valve cover 312, and the convex portions 312a are interference fit with the valve seat 311. A first exhaust gap 313c is formed between the area of ​​the outer circumferential surface of the valve cover 312 where the convex portions 312a are not provided and the valve seat 311, that is, in the circumferential direction of the valve cover 312, the air outlet is formed between two adjacent convex portions 312a. By providing the first exhaust gap 313c between the valve cover 312 and the valve seat 311 to form the air outlet of the valve cavity 313, the valve cavity 313 of the valve body 31 can be communicated with the outside of the housing through the first exhaust gap 313c formed between the valve cover 312 and the valve seat 311, and the structure is simple and easy to process.

[0172] According to some embodiments of the present application, the valve cover 312 may be connected to the valve seat 311, and then connected to the end cover 21 by using the valve seat 311. Specifically, the end of the valve seat 311 away from the seat bottom wall 3115 is provided with a first sink 3112, and at least part of the valve cover 312 is accommodated in the first sink 3112. That is, the valve cover 312 may be located in the first sink 3112 as a whole, or partially in the first sink 3112, that is, the valve cover 312 may extend out of the first sink 3112, or may not extend out of the first sink 3112. By providing a first recessed groove 3112 on the valve seat 311, and at least partially accommodating the valve cover 312 in the first recessed groove 3112, the one-way valve 30 adopting such a structure can save the space occupied by the valve body 31 on the one hand, and can improve the structural stability of the valve cover 312 assembled on the valve seat 311 on the other hand, and can play a certain protective role on the valve cover 312, so as to reduce the wear or damage of the valve cover 312.

[0173] According to some embodiments of the present application, the valve cover 312 and the valve seat 311 may be connected to the end cover 21 respectively. Specifically, the valve cover 312 is connected to the end cover 21, and the gas outlet includes a second exhaust gap (not shown) formed between the valve cover 312 and the end cover 21. The valve cover 312 is connected to the end cover 21, so that the valve cover 312 and the valve seat 311 jointly define a valve cavity 313 for accommodating the valve core 32. When the valve is opened, the blocking member 321 opens the fourth through hole 3114, and the gas enters the valve cavity 313. At this time, any opening or gap on the upper part of the valve cavity 313 can be used as an outlet; in other words, the blocking member 321 controls the sealing of the battery cell, and other areas of the valve cavity do not bear the sealing function, and an opening or gap can be set to discharge the gas in the valve cavity; the second exhaust gap between the valve cover 312 and the end cover 21 can be a gap left by local welding, or a convex portion can be set on the connecting surface of the two, and the convex portion is used for connection, and the area without the convex portion forms the second exhaust gap.

[0174] According to some embodiments of the present application, the one-way valve 30 is disposed on the end cover 21, the valve body 31 of the one-way valve 30 faces the interior of the housing and at least a portion of the valve body 31 protrudes from the inner surface 21b of the end cover 21. The one-way valve 30 includes a valve body 31 and a valve core 32, the valve body 31 has a valve cavity 313 inside, and the valve core 32 is disposed in the valve cavity 313. The valve body 31 includes a valve seat 311, and the valve seat 311 includes a seat bottom wall 3115 and a seat side wall 3116 connected to the seat bottom wall 3115. The seat bottom wall 3115, the seat side wall 3116 and the end cover 21 enclose a valve cavity 313. The end cover 21 is provided with an outlet of the valve cavity 313, for example, the first exhaust hole 291 can be used as the outlet to connect the valve cavity 313 with the outside of the shell; the valve seat 311 is provided with an inlet of the valve cavity 313 to connect the valve cavity 313 with the inside of the shell, for example, the fourth through hole 3114 penetrating the seat bottom wall 3115 can be used as the inlet. In this embodiment, the valve body 31 of the one-way valve 30 can only have the valve seat 311 without the valve cover 312, and the valve seat 311 is directly connected to the end cover 21; or the end cover 21 can be used as the valve cover 312 of the valve body 31. In this way, the installation height of the one-way valve 30 can be reduced.

[0175] According to some embodiments of the present application, a third recessed groove (not shown) is provided on one side of the end cover 21 facing the inside of the housing and is recessed relative to the inner surface 21b of the end cover 21. At least a portion of the seat side wall 3116 is accommodated in the third recessed groove and connected to the end cover 21. Fig.13 In the illustrated embodiment, the flange wall 31222 is connected to the end cover 21 in the same manner, which is not illustrated in this article. In this embodiment, by providing a third sink groove on the side of the end cover 21 facing the inside of the housing, and at least a portion of the seat side wall 3116 is accommodated in the third sink groove, the one-way valve 30 with such a structure can save the space occupied by the valve body 31 in the thickness direction of the end cover 21.

[0176] According to some embodiments of the present application, the one-way valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve cavity 313 inside. The valve core 32 is disposed in the valve cavity 313. The valve core 32 is used to block the air inlet 313a. The valve core 32 is configured to open the air inlet 313a under the action of the gas inside the shell and release the gas inside the battery cell 20. The structure of the valve core 32 can be various, for example, Figure 4 In the figure, the valve core 32 may include an elastic member 322 and a sealing member 321, the elastic member 322 is arranged in the valve cavity 313, the sealing member 321 is movably arranged in the valve cavity 313, and the sealing member 321 is used to block the air inlet 313a under the action of the elastic member 322, and is used to open the air inlet 313a under the action of the gas inside the shell.

[0177] Please refer to Figure 4 and Fig.18, Fig.18 Schematic diagram of the cross-sectional structure of a one-way valve according to one or more embodiments. According to some embodiments of the present application, the elastic member 322 is arranged along the axial direction Y of the valve cavity 313, and the two ends of the elastic member 322 abut against the blocking member 321 and the cavity top surface of the valve cavity 313 respectively, and the elastic member 322 is in a compressed state and is located between the cavity top surface of the valve cavity 313 and the blocking member 321, so that the elastic member 322 can apply elastic force to the blocking member 321, so that the blocking member 321 can abut against the cavity bottom surface of the valve cavity 313 to block the air inlet 313a.

[0178] According to some embodiments of the present application, the valve body 31 includes a valve seat 311 and a valve cover 312. The valve cover 312 and the valve seat 311 enclose a valve cavity 313. The two ends of the elastic member 322 respectively abut against the blocking member 321 and the cover top wall 3121 of the valve cover 312. The valve body 31 includes the valve cover 312. A first guide column 31211 is convexly provided on one side of the valve cover 312 facing the valve cavity 313. Part of the elastic member 322 is sleeved on the outer side of the first guide column 31211 to achieve positioning of the elastic member 322.

[0179] In one embodiment, a second guide column 3212 b is protrudingly provided on one side of the blocking member 321 facing the valve cover 312 , and a portion of the elastic member 322 is sleeved on the outer side of the second guide column 3212 b .

[0180] The one-way valve 30 adopting this structure can play a certain positioning role on the elastic member 322 through the first guide column 31211 and the second guide column 3212b, so as to facilitate the assembly of the elastic member 322, which is conducive to reducing the difficulty of assembling the elastic member 322. On the other hand, the first guide column 31211 and the second guide column 3212b can play a certain guiding role when the elastic member 322 is compressed, so as to reduce the radial deformation of the elastic member 322 during the compression process, so that the elastic member 322 can be stably compressed, which is conducive to improving the reliability of the use of the elastic member 322, and further can reduce the risk of the blocking member 321 accidentally opening the air inlet 313a. The elastic member 322 can be a spring. Of course, in other embodiments, the elastic member 322 can also be a spring or elastic rubber. The material of the elastic member 322 includes steel, iron or aluminum.

[0181] According to some embodiments of the present application, the diameter of the first guide column 31211 is D1, and the inner diameter of the elastic member 322 is D2, satisfying 0mm<D2-D1≤5mm.

[0182] The elastic member 322 is a spring, and the inner diameter D2 of the elastic member 322 is the diameter of the cavity formed inside the spring. 0mm<D2-D1≤5mm, that is, when the first guide column 31211 and the elastic member 322 are coaxially arranged, the size of the gap between the first guide column 31211 and the elastic member 322 is greater than 0mm and less than or equal to 5mm.

[0183] Exemplarily, the difference between the inner diameter of the elastic member 322 and the diameter of the first guide column 31211 can be 0mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0184] By setting the difference between the inner diameter of the elastic member 322 and the diameter of the first guide column 31211 to be greater than 0 mm and less than or equal to 5 mm, on the one hand, the phenomenon that the elastic member 322 is not convenient to be assembled on the first guide column 31211 due to the difference between the inner diameter of the elastic member 322 and the diameter of the first guide column 31211 being less than or equal to 0 can be alleviated, so as to reduce the scratching phenomenon when the elastic member 322 is sleeved on the first guide column 31211; on the other hand, the phenomenon that the gap between the elastic member 322 and the first guide column 31211 is too large due to the difference between the inner diameter of the elastic member 322 and the diameter of the first guide column 31211 is too large can be alleviated, so as to reduce the radial movement or radial deformation of the elastic member 322, thereby improving the balance of the elastic force of the elastic member 322 acting on the blocking member 321, so as to reduce the risk of the blocking member 321 accidentally opening the air inlet 313a.

[0185] According to some embodiments of the present application, the diameter of the second guide column 3212b is D3, wherein the diameter of the second guide column 3212b refers to the diameter of the second guide column 3212b body, and does not include the area of ​​the limiting protrusion 3212a provided on the second guide column 3212b. The inner diameter of the elastic member 322 is D2, satisfying 0mm<D3-D1≤5mm.

[0186] The elastic member 322 is a spring, and the inner diameter D2 of the elastic member 322 is the diameter of the cavity formed inside the spring.

[0187] 0mm<D3-D1≤5mm, that is, when the second guide post 3212b and the elastic member 322 are coaxially arranged, the size of the gap between the second guide post 3212b and the elastic member 322 is greater than 0mm and less than or equal to 5mm.

[0188] Exemplarily, the difference between the inner diameter of the elastic member 322 and the diameter of the second guide column 3212b can be 0mm, 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm, etc.

[0189] By setting the difference between the inner diameter of the elastic member 322 and the diameter of the second guide column 3212b to be greater than 0 mm and less than or equal to 5 mm, on the one hand, the phenomenon that the elastic member 322 is not convenient to be assembled on the second guide column 3212b due to the difference between the inner diameter of the elastic member 322 and the diameter of the second guide column 3212b being less than or equal to 0 can be alleviated, so as to reduce the scratching phenomenon when the elastic member 322 is sleeved on the second guide column 3212b. On the other hand, the phenomenon that the gap between the elastic member 322 and the second guide column 3212b is too large due to the difference between the inner diameter of the elastic member 322 and the diameter of the second guide column 3212b is too large can be alleviated, so as to reduce the radial movement or radial deformation of the elastic member 322, thereby improving the balance of the elastic force of the elastic member 322 acting on the blocking member 321, so as to reduce the risk of the blocking member 321 accidentally opening the air inlet 313a.

[0190] According to some embodiments of the present application, in the axial direction (Y direction) of the valve cavity 313, the two ends of the elastic member 322 respectively abut against the valve cover 312 and the blocking member 321, and the distance between the first abutting surface of the valve cover 312 and the second abutting surface of the blocking member 321 is L1, and L1 is the assembly space of the elastic member 322. Among them, the two ends of the elastic member 322 respectively abut against the side surface of the valve cover 312 facing the valve cavity 313 and the side surface of the blocking member 321 facing the valve cover 312, and the distance between the two is the assembly space L1 of the elastic member 322. Specifically, the cover top wall 3121 has a first abutting surface 3121a facing the valve cavity 313, and the blocking member 321 has a second abutting surface 3212c facing the cover top wall 3121, and L1 is the distance between the first abutting surface 3121a and the second abutting surface 3212c. The first abutting surface 3121 a and the second abutting surface 3212 c are surfaces of the valve cover 312 and the blocking member 321 that abut against the elastic member 322 , respectively.

[0191] According to some embodiments of the present application, in the axial direction of the elastic member 322, there is a gap between the end surface of the first guide column 31211 away from the valve cover 312 and the end surface of the second guide column 3212b close to the valve cover 312. The gap can provide space for the blocking member 321 to move.

[0192] According to some embodiments of the present application, along the axial direction Y of the valve cavity 313, the size of the gap between the valve cover 312 and the blocking member 321 is H1, which satisfies 0mm

[0193] The valve cover 312 has a first guide post 31211 protruding from the side facing the valve cavity 313, and the plugging member 321 has a second guide post 3212b protruding from the side facing the valve cover 312. The gap between the valve cover 312 and the plugging member 321 is the gap between the end face of the first guide post 31211 away from the valve cover 312 and the end face of the second guide post 3212b close to the valve cover 312. Fig.18 In other words, in the axial direction Y of the valve cavity 313, the sum of the height H2 of the first guide column 31211 and the height H3 of the second guide column 3212b is less than the assembly space L1 of the elastic member 322, that is, in the axial direction, the height H2 of the first guide column 31211 + the height H3 of the second guide column 3212b < the spring compression space L1.

[0194] Exemplarily, the size H1 of the gap between the valve cover 312 and the blocking member 321 may be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.

[0195] By setting the size of the gap between the valve cover 312 and the sealing member 321 in the axial direction Y to be greater than 0 mm and less than or equal to 5 mm, on the one hand, the obstruction of the valve cover 312 to the sealing member 321 can be reduced, so that there is space between the valve cover 312 and the sealing member 321 for the sealing member 321 to move along the axial direction Y, so that when the gas inside the shell pushes the sealing member 321, the sealing member 321 can open the air inlet 313a for exhaust. On the other hand, the phenomenon that the one-way valve 30 occupies too much space in the axial direction Y due to the excessive gap between the valve cover 312 and the sealing member 321 can be alleviated, which is beneficial to improving the space utilization rate of the battery cell 20.

[0196] Please refer to Fig.19 , Fig.19 Schematic diagram of the state of the elastic member according to one or more embodiments. Taking the elastic member 322 as a spring as an example, the initial length L0 of the spring is the natural length of the spring before being compressed; by configuring L0>L1, the spring can have a certain initial elastic force after being assembled into the valve cavity 313 to push the blocking member 321 to press against the bottom surface of the valve cavity, thereby improving the sealing performance.

[0197] Furthermore, the physical length L2 of the spring is configured so that L1>L2. The physical length of the spring is the length of the main body of the spring after the spring is fully compressed.​ Fig.19 As shown, Fig.19 State 1 in the figure is the state where the spring is not compressed. In this state, there is a gap between the entity structures of the spring and it can be further compressed. Fig.19 State 2 in the figure is the state after the spring is fully compressed. In this state, there is no gap between the physical structures of the spring and it cannot be further compressed. The physical length of the spring L2 = d1*n1+d2+d3, where d1 is the spring wire diameter, n1 is the maximum number of turns of the spring in the axial direction, d2 is the thickness of the outermost spring at one end of the spring, and d3 is the thickness of the outermost spring on the other side of the spring. Fig.18 and 19 As shown in the figure, the spring is a spiral cylindrical coil, and the spring wire diameter d1 is the diameter of each coil of the spring body. As the number of spiral coils increases, the length of the spring body is the sum of the length of each coil of the spring body, that is, d1*n1. Fig.18 As shown, the number of turns of the spring is 4, and the length of the entity of this part after being fully compressed is d1*4. The end of the spring can be ground flat for easy assembly. The so-called grinding process refers to grinding a part of the originally cylindrical spring entity to make its top surface smoother. After the grinding process, the spring entity becomes thinner, that is, it is no longer a complete cylinder. Then the thickness d2 and d3 of the spring entity in this area will be less than the spring wire diameter d1; of course, in some embodiments, the end of the spring may not be processed. In this case, the thickness of the spring entity is equal to the spring wire diameter d1, that is, d2≤d1, d3≤d1. Therefore, the overall length of the spring entity is L2=d1*n1+d2+d3. By setting L1>L2, the spring will not be completely compacted after assembly, and there is still room for compression activity.

[0198] According to some embodiments of the present application, the compression margin of the elastic member 322 in a compressed state between the valve cover 312 and the blocking member 321 is greater than or equal to 0.5 mm, that is, L1-L2>0.5 mm. The elastic member 322 has enough compression margin for the blocking member 321 to move along the axial direction Y of the valve cavity, so that the blocking member 321 can open the air inlet 313a. If the elastic member 322 is a spring, the sum of the gaps between the coils of the spring on the axial direction Y of the valve cavity is greater than or equal to 0.5 mm. Exemplarily, L1-L2 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc.

[0199] According to some embodiments of the present application, the blocking member 321 includes a clamping portion 3212 and a sealing portion 3211. Along the axial direction of the valve chamber 313, the two ends of the elastic member 322 respectively abut against the valve cover 312 and the clamping portion 3212. The sealing portion 3211 is connected to the side of the clamping portion 3212 away from the valve cover 312. The sealing portion 3211 is used to seal the air inlet 313a.

[0200] The sealing part 3211 is connected to the side of the pressing part 3212 away from the cover top wall 3121, and the sealing part 3211 is used to block the air inlet 313a. The elastic member 322 is arranged between the cover top wall 3121 and the pressing part 3212. The pressing part 3212 can be pressed against the sealing part 3211 under the elastic force of the elastic member 322, so that the upper surface of the sealing part 3211 and the pressing part 3212 are effectively in contact, so that the sealing part 3211 is against the bottom surface of the valve cavity 313, thereby blocking the air inlet 313a through the sealing part 3211. A second guide column 3212b can be protruded on the side of the pressing part 3212 facing the cover top wall 3121, and part of the elastic member 322 is sleeved on the outer side of the second guide column 3212b.

[0201] In other embodiments, the blocking member 321 may also be a sealing member as a whole, such as a rubber pad or a silicone pad, that is, the blocking member 321 only includes a sealing portion 3211, and the two ends of the elastic member 322 respectively abut against the valve cover 312 and the sealing portion 3211. Of course, in other embodiments, the valve core 32 may also be a whole elastic member, such as elastic rubber.

[0202] According to some embodiments of the present application, the rigidity of the pressing portion 3212 is greater than the rigidity of the sealing portion 3211, and the setting of the pressing portion 3212 can effectively transmit the force applied by the elastic member 322 to the sealing portion 3211. In other words, the rigidity of the pressing portion 3212 is greater than the rigidity of the sealing portion 3211, that is, the deformation resistance of the pressing portion 3212 is greater than the deformation resistance of the sealing portion 3211, so that the pressing portion 3212 can better press the sealing portion 3211 on the bottom surface of the installation cavity to block the air inlet 313a. Exemplarily, the material of the pressing portion 3212 can be various, such as steel, iron or aluminum. Similarly, the material of the sealing portion 3211 can also be various, such as rubber, silicone or plastic.

[0203] Optionally, the connection structure between the pressing portion 3212 and the sealing portion 3211 may be various, such as clamping, bolting, or bonding.

[0204] By configuring the blocking member 321 to include a clamping portion 3212 and a sealing portion 3211, the clamping portion 3212 is disposed on the side of the sealing portion 3211 facing the valve cover 312, the sealing portion 3211 is used to block the air inlet 313a, and the two ends of the elastic member 322 respectively abut against the valve cover 312 and the clamping portion 3212, so that the elastic member 322 can exert an elastic force on the sealing portion 3211 through the clamping portion 3212, which is beneficial to improving the balance of the elastic force of the elastic member 322 acting on the sealing portion 3211, and further can effectively improve the sealing effect of the sealing portion 3211 on the air inlet 313a.

[0205] According to some embodiments of the present application, the material of the sealing portion 3211 is selected to be resistant to electrolyte, such as fluororubber, PFA, EPDM, etc. Different sealing materials have different physical properties, and the forces required to achieve sealing are also different accordingly.

[0206] Please refer to Fig. 20 , Fig. 20 Schematic diagram of the structure of the blocking member 321 of the one-way valve according to one or more embodiments. According to some embodiments of the present application, the outer circumferential surface of the blocking member 321 is provided with a plurality of limiting protrusions 3212a, and the plurality of limiting protrusions 3212a are arranged at intervals along the circumference of the blocking member 321.

[0207] The limiting protrusion 3212a cooperates with the side surface of the valve cavity 313 for guiding, that is, the limiting protrusion 3212a cooperates with the cavity wall surface of the valve cavity 313 when the blocking member 321 moves along the axial direction of the valve cavity 313, so as to play a guiding and limiting role. The limiting protrusion 3212a and the cavity side surface of the valve cavity 313 can be clearance-matched. In other embodiments, the one-way valve 30 can also be other structures, for example, the cavity side surface of the valve cavity 313 is provided with a guide groove (not shown) extending along the axial direction of the valve cavity 313, and the limiting protrusion 3212a extends into the guide groove. The limiting protrusion 3212a can move in the guide groove along the axial direction of the valve cavity 313 when the blocking member 321 opens the air inlet 313a, so as to play a guiding and limiting role. A plurality of guide grooves can be provided, and the plurality of guide grooves respectively cooperate with the plurality of limiting protrusions 3212a. Optionally, the limiting protrusion 3212a may have a variety of shapes, such as a semicircular, triangular, trapezoidal or rectangular structure. For example, Fig. 20 In the embodiment, the limiting protrusion 3212a is in a semicircular shape.

[0208] A plurality of spaced limiting protrusions 3212a are provided on the outer circumferential surface of the blocking member 321, and the limiting protrusions 3212a are guided and matched with the side surface of the valve cavity 313, so that when the blocking member 321 moves along the axial direction of the valve cavity 313, the limiting protrusions 3212a and the side surface of the valve cavity 313 can guide and limit the blocking member 321, so as to improve the stability of the movement of the blocking member 321. Exemplarily, the limiting protrusions 3212a are provided on the outer circumferential surface of the pressing portion 3212.

[0209] Please refer to Fig.21 , Fig.21Schematic diagram of the cross-sectional structure of the wall according to one or more embodiments. According to some embodiments of the present application, the one-way valve 30 is arranged on the wall, and the one-way valve 30 may be arranged on the end cover 21, and the end cover 21 is provided with a first exhaust hole 291, and the first exhaust hole 291 includes a through hole section 280 and a first hole section 281, and the through hole section 280 and the first hole section 281 are arranged along the thickness direction of the end cover 21, and the through hole section 280 connects the inside of the shell with the outside of the shell, and the first hole section 281 is located on the side of the through hole section 280 away from the inside of the shell, and the aperture of the first hole section 281 is larger than the aperture of the through hole section 280, and the one-way valve 30 is at least partially accommodated in the first hole section 281.

[0210] The first exhaust hole 291 is a countersunk hole recessed relative to the outer surface 21a of the end cover 21. When the one-way valve 30 is connected to the end cover 21, part of the structure of the one-way valve 30 can be embedded in the first exhaust hole 291 to reduce the installation height.

[0211] Please refer to Figure 8 and Fig.16 The one-way valve 30 is disposed on the outer surface 21a of the end cover 21. The valve body 31 of the one-way valve 30 may face the outside of the housing and at least a portion of the valve body 31 may protrude from the outer surface 21a of the end cover 21. Alternatively, the valve body 31 of the one-way valve 30 may face the inside of the housing and at least a portion of the valve body 31 may protrude from the inner surface 21b of the end cover 21.

[0212] See also Figure 8 According to some embodiments of the present application, a first step surface 311b and a second step surface 311c are provided on the side of the valve seat 311 facing the valve cover 312, the first step surface 311b is closer to the valve cover 312 than the second step surface 311c, and the first sink groove 3112 is provided on the first step surface 311b.

[0213] The first hole section 281 includes a hole side surface arranged circumferentially, and the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30 is welded to the hole side surface. The outer peripheral surface of the second step surface 311c is welded to the hole side surface.

[0214] According to some embodiments of the present application, the hole side surface matches the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30, and the hole side surface and the outer peripheral surface of the valve cover 312 / valve seat 311 of the one-way valve 30 are arranged at an acute angle to the central axis of the first exhaust hole 291. Through this arrangement, the connection strength can be enhanced.

[0215] According to some embodiments of the present application, the one-way valve 30 is welded to the end cover 21. Figure 8As shown, the valve seat 311 of the one-way valve 30 can be welded to the end cover 21; specifically, the valve cover 312 of the one-way valve 30 is connected to the valve seat 311, and the valve seat 311 is welded to the end cover 21. In other embodiments, when the one-way valve 30 is selected Fig.12 In the illustrated embodiment, the valve seat 311 of the one-way valve 30 may be connected to the valve cover 312 , and the valve cover 312 may be welded to the end cover 21 .

[0216] According to some embodiments of the present application, a stress relief groove is provided around the third weld mark of the valve cover 312 / valve seat 311 and the end cover 21. The stress relief groove may be provided only on the end cover 21, or only on the valve cover 312 / valve seat 311, or on both the end cover 21 and the valve cover 312 / valve seat 311. Optionally, a first stress relief groove is provided on the surface of the valve seat 311 / valve cover 312 facing the outside of the shell; and / or a second stress relief groove is provided on the surface of the wall facing the outside of the shell. Fig.16 As shown, a first stress release groove 311 a is provided on the valve seat 311 around the third weld mark W3 between the valve seat 311 and the end cover 21 .

[0217] According to some embodiments of the present application, the exhaust assembly includes a gas permeable membrane assembly 40 , wherein the gas permeable membrane assembly 40 includes a gas permeable membrane 41 , and the gas permeable membrane 41 is configured to allow gas inside the battery cell to pass through the gas permeable membrane and be discharged.

[0218] According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41, which is made of a breathable material and has good breathability, allowing gas molecules to pass through. By selecting the breathable membrane assembly 40 as the exhaust assembly, the battery cell can be in a closed state. The internal gas can be discharged through the breathable membrane 41, and the internal gas of the battery cell shell can be discharged outside the shell in time, so that the gas pressure inside the battery cell shell is not too high, reducing the risk of the pressure relief mechanism opening the valve in advance, and can greatly increase the life of the battery cell.

[0219] Furthermore, the breathable membrane 41 also has liquid isolation properties, blocking the passage of liquid, so it can prevent the electrolyte from overflowing while discharging gas. In addition, the breathable membrane 41 can also block external water vapor, dust and impurities from entering the battery cell, protect the internal environment of the battery cell, and effectively improve the reliability of the battery cell. The breathable membrane 41 also has good weather resistance, chemical corrosion resistance, and structural stability. If it is an automotive power battery, it also needs to have oleophobicity. Therefore, the material of the breathable membrane 41 can be selected from polymer materials, such as polytetrafluoroethylene, polypropylene, etc. In addition, since the generation of gas inside the battery cell will cause the internal pressure to rise rapidly, the breathable membrane needs to have certain mechanical strength and elasticity.

[0220] Please refer to Fig. 22 , Fig. 22 Schematic diagram of the cross-sectional structure of a breathable membrane assembly according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 includes a breathable membrane 41 and a connector 42, and the connector 42 is used to support the breathable membrane 41. The connector 42 is provided with a first breathable hole 491, the breathable membrane 41 is provided on the connector 42, the breathable membrane 41 covers the first breathable hole 491, and the breathable membrane is configured to allow the gas inside the battery cell to pass through the breathable membrane and be discharged.

[0221] The connector 42 can support the breathable membrane 41 and reduce the risk of excessive deformation of the breathable membrane 41. At the same time, the connector 42 can also serve as a medium for connecting other components of the breathable membrane assembly 40. The breathable membrane 41 is connected to other components through the connector 42 to improve the stability of the connection. The connector 42 is provided with at least one first air hole 491 as a release channel for the gas inside the battery cell so that the gas can pass through the connector 42. The shape of the first air hole 491 includes geometric shapes such as circle, square, and ellipse. The connector 42 can also be provided with multiple first air holes 491. The aperture, shape, and arrangement of the first air holes 491 are not specifically limited here. Optionally, the aperture of the first air hole 491 can be less than or equal to the aperture of the exhaust hole on the battery cell.

[0222] In one embodiment, the connector 42 may be a metal part, a resin part, etc. The material of the metal part may be copper, iron, aluminum, steel, or aluminum alloy, etc. By selecting the connector 42 as a metal part, it is convenient to weld the connector 42 to the wall. The following will take the connector 42 as a metal part to illustrate the present application scheme, but it should not be limited to this, and should not bring limitations to the present application scheme, and it is still applicable to connectors made of non-metal materials.

[0223] like Fig. 22 As shown in (a), the air permeable membrane 41 can be directly disposed on the surface of the metal member 42. In other embodiments, a sink can also be disposed on the metal member 42.

[0224] See also Fig. 22 As shown in (b), according to some embodiments of the present application, the metal member 42 has a first annular table surface T1 that is recessed relative to the surface of the metal member 42, the first annular table surface T1 is arranged around the first air hole 491, and the air permeable membrane 41 is arranged on the first annular table surface T1. Through this arrangement, the installation height of the air permeable membrane assembly 40 can be reduced.

[0225] See also Fig.23 , Fig.23Schematic diagram of the cross-sectional structure of the breathable membrane assembly 40 according to one or more embodiments. According to some embodiments of the present application, the breathable membrane assembly 40 further includes a backing member 43, which is disposed between the breathable membrane 41 and the metal member 42, and the air permeability of the backing member 43 is greater than the air permeability of the breathable membrane 41.

[0226] The breathable membrane assembly 40 includes a breathable membrane 41, a metal member 42 and a backing member 43. The breathable membrane 41 is disposed on the metal member 42. The backing member 43 is disposed between the breathable membrane 41 and the metal member 42. The backing member 43 is used to support the breathable membrane 41 and allow gas to pass through the breathable membrane 41.

[0227] The backing member 43 can support the breathable membrane 41 and reduce the risk of deformation of the breathable membrane 41. The backing member 43 is made of a material with better air permeability than the breathable membrane 41 so as not to affect the air permeability of the breathable membrane 41; the backing member 43 also has the characteristics of corrosion resistance and high temperature resistance. The material selection of the backing member 43 is rich, including porous polymers such as polypropylene, polyamide, polytetrafluoroethylene, polyperfluoroethylene propylene, etc., and can also be metal organic framework porous materials, as well as carbon membrane and ceramic porous materials, etc., which are not limited here.

[0228] like Fig.23 As shown in (a), the metal part 42 also has a second annular table T2 that is recessed relative to the surface of the metal part 42. The second annular table T2 is arranged around the first air hole 491, and the backing member 43 is arranged on the second annular table T2. The second annular table T2 carries the backing member 43, and the breathable membrane 41 can be directly attached to the surface of the metal part 42. In this way, because the thickness of the breathable membrane 41 is relatively small, the overall height of the breathable membrane assembly 40 is relatively small. By reducing the setting of the recessed surface on the metal part 42, on the one hand, the manufacturing process can be simplified, and on the other hand, the strength of the metal part 42 can be improved.

[0229] like Fig.23 As shown in (b), the metal part 42 has a first annular table T1 and a second annular table T2 which are recessed relative to the surface of the metal part 42, and a transition surface T3. The first annular table T1 is arranged around the second annular table T2, and the transition surface T3 connects the first annular table T1 and the second annular table T2. The first annular table T1 is closer to the surface of the metal part 42 than the second annular table T2. The second annular table T2 is arranged around the first air hole 491. The backing member 43 is arranged on the second annular table T2, and the air permeable membrane 41 is arranged on the first annular table T1.

[0230] The first annular table surface T1 and the second annular table surface T2 are formed by the surface of the metal member 42 being recessed inwardly, and the first annular table surface T1 and the second annular table surface T2 may be formed by stamping the metal member 42, or the first annular table surface T1 and the second annular table surface T2 may be formed by etching the metal member 42 to remove part of the structure. The recess depth of the first annular table surface T1 and the second annular table surface T2 relative to the surface of the metal member 42 may be set according to the thickness of the breathable membrane 41 and the backing member 43. Preferably, the recess depth of the second annular table surface T2 relative to the first annular table surface T1 (i.e., the height of the transition surface T3) is equal to the thickness of the backing member 43, so that the second annular table can accommodate the backing member 43, and the surface of the backing member 43 facing the breathable membrane 41 is flush with the first annular table surface T1. Furthermore, the depression depth of the first annular platform T1 relative to the surface of the metal member 42 is equal to the thickness of the breathable membrane 41 , so that the first annular platform can accommodate the breathable membrane 41 , and the side surface of the breathable membrane 41 away from the metal member 42 is flush with the surface of the metal member 42 .

[0231] By providing a recessed sink on the metal member 42 , the surface of the breathable membrane 41 can be flush with the surface of the metal member 42 , thereby reducing the overall height of the breathable membrane assembly 40 and further reducing the installation height of the breathable membrane assembly 40 .

[0232] In one embodiment, the breathable membrane 41 and the metal part 42 are compositely connected, for example, the breathable membrane 41 and the metal part 42 can be connected by using a nano injection molding process. Nano injection molding refers to nano molding technology (NMT, i.e., Nano Molding Technology), which is a process of combining metal and plastic using nano technology. That is, the metal surface is first nano-treated, and then the plastic is directly injection molded on the metal surface, so that the metal and plastic can be integrally molded and finally combined into a product. The "nano" referred to here refers to a microporation process, that is, the metal surface is subjected to nano-scale microporation treatment through a specific solution, and the main purpose is to make the metal surface and the plastic better combined and improve the connection strength.

[0233] According to some embodiments of the present application, the breathable membrane assembly 40 is disposed on the wall portion, the wall portion has a first sinking platform S1 that is recessed relative to the surface of the wall portion, the first sinking platform S1 is disposed around the second exhaust hole 292, and the breathable membrane assembly 40 is at least partially located on the first sinking platform S1. The breathable membrane assembly 40 may be disposed on the end cover 21.

[0234] Please refer to Fig.24 and Fig.25 , Fig.24 is a schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. Fig.25Schematic diagram of a partial cross-sectional structure of a battery cell 20 according to one or more embodiments. According to some embodiments of the present application, the end cap 21 has a first sinking platform S1 that is recessed relative to the surface of the end cap 21, the first sinking platform S1 is arranged around the second exhaust hole 292, and at least a portion of the breathable membrane assembly 40 is arranged on the first sinking platform S1.

[0235] The end cap 21 includes an outer surface 21a and an inner surface 21b disposed opposite to each other, the outer surface 21a is disposed toward the outside of the shell, and the inner surface 21b is disposed toward the inside of the shell. The breathable membrane assembly 40 can be disposed on the side of the end cap 21 facing the inside of the shell, or on the side of the end cap 21 facing the outside of the shell.

[0236] like Fig.24 As shown in (a) and (b), the breathable membrane assembly 40 is arranged on the side of the end cap 21 facing the inside of the shell. The end cap 21 has an outer surface 21a and an inner surface 21b arranged opposite to each other, the outer surface 21a is arranged toward the outside of the shell, and the inner surface 21b is arranged toward the inside of the shell. The end cap 21 has a first sink S1 that is recessed relative to the inner surface 21b of the end cap 21.

[0237] Specifically, the first sinking platform S1 is recessed relative to the inner surface 21 b of the end cover 21 , and the breathable membrane assembly 40 is disposed on the first sinking platform S1 . Optionally, the breathable membrane assembly 40 may be connected to the end cover 21 via a metal member 42 .

[0238] Among them, the first depression S1 is formed by the inner surface 21b of the end cover 21 being recessed in the direction of the outer surface 21a of the end cover 21. The end cover 21 may be stamped to form the recessed first depression S1, or the end cover 21 may be etched to remove part of the structure to form the recessed first depression S1. The recess depth of the first depression S1 relative to the inner surface 21b of the end cover 21 can be set according to the thickness of the breathable membrane assembly 40. The thickness of the breathable membrane assembly 40 is the overall thickness including the breathable membrane 41, the metal part 42 and the backing part 43. As mentioned above, the breathable membrane 41 and the backing part 43 can be accommodated in the annular platform on the metal part 42 that is recessed relative to the surface of the metal part 42, that is, the overall thickness of the breathable membrane assembly 40 can be equal to the thickness of the metal part 42. Preferably, the depression depth of the first depression S1 relative to the inner surface 21b of the end cover 21 is equal to the thickness of the breathable membrane assembly 40, so that the breathable membrane assembly 40 is accommodated in the first depression S1, and the surface of the breathable membrane assembly 40 facing the inside of the shell is flush with the inner surface 21b of the end cover 21. In this way, the installation height of the breathable membrane assembly 40 can be reduced, thereby reducing the occupation of the internal space of the battery cell 20 shell and improving the space utilization rate inside the shell.

[0239] like Fig.24As shown in (a), the air permeable membrane 41 may be arranged on the side of the metal member 42 facing the inside of the housing; this arrangement can reduce the influence of the working environment of the battery cell 20 on the air permeable membrane 41. Fig.24 As shown in (b), the breathable membrane 41 may be disposed on the side of the metal member 42 facing the end cap 21 , that is, the breathable membrane 41 is disposed between the metal member 42 and the end cap 21 . This arrangement can facilitate assembly of the breathable membrane assembly 40 .

[0240] like Fig.25 As shown, the breathable membrane assembly 40 is arranged on the side of the end cover 21 facing the outside of the housing. Specifically, the first sinking platform S1 is recessed relative to the outer surface 21a of the end cover 21, and the breathable membrane assembly 40 is arranged on the first sinking platform S1 and connected to the end cover 21 through the metal member 42. In this embodiment, the first sinking platform S1 is formed by the outer surface 21a of the end cover 21 being recessed toward the inner surface 21b of the end cover 21. Similarly, the recessed depth of the first sinking platform S1 relative to the outer surface 21a of the end cover 21 can be equal to the thickness of the breathable membrane assembly 40.

[0241] like Fig.25 As shown, the breathable membrane 41 is arranged on the side of the metal part 42 facing the inside of the housing, that is, the breathable membrane 41 is arranged between the end cover 21 and the metal part 42. Through this arrangement, the breathable membrane 41 can be less affected by the working environment of the battery cell 20. In other embodiments, the breathable membrane 41 can also be arranged on the side of the metal part 42 facing the outside of the housing.

[0242] According to some embodiments of the present application, the connector is welded to the wall; optionally, a stress relief groove is provided around the fourth weld mark between the connector and the wall; optionally, a third stress relief groove is provided on the connector around the fourth weld mark between the connector and the wall; and / or a fourth stress relief groove is provided on the wall around the fourth weld mark between the connector and the wall. Fig.26 As shown, the connecting member is a metal member, the metal member 42 is welded to the end cover 21 , and a third stress release groove 421 is provided on the metal member 42 around the fourth weld mark W4 between the metal member 42 and the end cover 21 .

[0243] Please refer to Fig.26 , Fig.26 FIG. 2 is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the first exhaust hole 291 and the second exhaust hole 292 are located on the same wall. Fig.26As shown, the first exhaust hole 291 and the second exhaust hole 292 are arranged at intervals on the end cover 21. In this embodiment, the valve body 31 of the one-way valve 30 is arranged on the outer surface 21a of the end cover 21, and at least a part of the valve body 31 protrudes from the outer surface 21a of the end cover 21; at least a part of the breathable membrane assembly 40 is arranged on the outer surface 21a of the end cover 21.

[0244] In some embodiments, a liquid injection hole is provided on the end cover 21, and the first exhaust hole 291 for assembling the one-way valve 30 can be the liquid injection hole; that is, after the battery cell 20 is filled with liquid, the one-way valve 30 is assembled on the liquid injection hole, and the one-way valve 30 is used to replace the original liquid injection hole sealing structure. By setting the first exhaust hole 291 for assembling the one-way valve 30 as the liquid injection hole, liquid can be injected into the shell through the first exhaust hole 291 before the one-way valve 30 is assembled into the first exhaust hole 291, so that there is no need to open a separate liquid injection hole on the shell, which is beneficial to improving the production efficiency of the battery cell 20 and reducing the manufacturing cost of the battery cell 20. The first exhaust hole 291 and the liquid injection hole can also be arranged at intervals.

[0245] Please refer to Figure 2 and Figure 3 The battery cell 20 also includes an insulating member 24, which is arranged on the side of the wall portion facing the inside of the shell; the insulating member 24 is provided with a third exhaust hole 293 and a fourth exhaust hole 294 that penetrate the insulating member 24 at intervals, the third exhaust hole 293 is connected to the first exhaust hole 291 on the wall portion, and the fourth exhaust hole 294 is connected to the second exhaust hole 292 on the wall portion.

[0246] The insulating member 24 is made of a material that will not contact the electrode assembly 23 inside the battery to form a short circuit. The insulating member 24 is used to protect the end cap 21 from being directly exposed to the electrode assembly 23 in the height direction to avoid contacting the electrode assembly 23 to form a short circuit.

[0247] The insulating member 24 is provided with a third exhaust hole 293 and a fourth exhaust hole 294 that penetrate the insulating member 24, so that the gas inside the battery enters the one-way valve 30 and the breathable membrane assembly 40 through the third exhaust hole 293 and the fourth exhaust hole 294. Further, the third exhaust hole 293 is connected to the first exhaust hole 291, and the fourth exhaust hole 294 is connected to the second exhaust hole 292, so that the exhaust is smoother.

[0248] According to some embodiments of the present application, an accommodating portion recessed relative to the surface of the insulating member 24 may be provided on the insulating member 24 to accommodate the inward protrusion of the end cap 21 , or the inward protrusion of the one-way valve, or the inward protrusion of the breathable membrane assembly 40 .

[0249] Please refer to Fig. 27 and Fig.28 , Fig. 27 It is a schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. Fig.28 Schematic diagram of a partial cross-sectional structure of a battery cell according to one or more embodiments. According to some embodiments of the present application, the battery cell 20 further includes a shielding member 50, which is mounted on the end cover 21, and is located on the side of the end cover 21 facing the outside of the housing, and shields the one-way valve 30 or the breathable membrane assembly 40.

[0250] Among them, Fig. 27 As shown, when the valve body 31 of the one-way valve 30 is disposed on the outer surface 21a of the end cover 21, and at least a portion of the valve body 31 protrudes from the inner surface 21b, a shielding member 50 may be provided to shield the one-way valve 30. Fig.28 As shown, when at least a portion of the breathable membrane assembly 40 is disposed on the outer surface 21 a of the end cover 21 , a shielding member 50 may be disposed so that the shielding member 50 shields the breathable membrane assembly 40 .

[0251] The covering member 50 can provide a certain degree of protection and shielding for the one-way valve 30 or the breathable membrane assembly 40. On the one hand, it can reduce the wear or damage of the one-way valve 30 or the breathable membrane assembly 40 in the external environment, and can reduce the risk of impurities or particulate matter in the external environment entering the one-way valve 30 or the breathable membrane assembly 40, which is beneficial to increasing the service life of the one-way valve 30 or the breathable membrane assembly 40. On the other hand, covering the one-way valve 30 or the breathable membrane assembly 40 by the covering member 50 can enhance the aesthetics of the outer surface 21a of the battery cell 20. On the other hand, it is convenient to connect other components such as detection elements on the side of the covering member 50 away from the one-way valve 30 or the breathable membrane assembly 40, so as to reduce the interference of the area of ​​the end cover 21 where the one-way valve 30 or the breathable membrane assembly 40 is set on the connection detection elements and other components.

[0252] According to some embodiments of the present application, the shielding member 50 may be installed on the end cover 21 by welding, interference fit, bolt connection, clamping or bonding.

[0253] According to some embodiments of the present application, a first exhaust passage is formed between the shielding member 50 and the end cover 21 , and the first exhaust passage connects the gas outlet of the one-way valve 30 or the breathable membrane assembly 40 with the outside of the battery cell.

[0254] The first exhaust passage includes a third exhaust gap 501, which is formed between the shielding member 50 and the end cover 21, and is used to connect the gas outlet and the outside of the housing. By setting the third exhaust gap, the gas discharged from the one-way valve 30 or the breathable membrane assembly 40 can be discharged to the outside of the housing through the third exhaust gap. The battery cell using this structure does not need to have a hole on the shielding member, which is conducive to reducing the difficulty of processing and can improve the appearance of the battery cell.

[0255] According to some embodiments of the present application, see Figure 1-Figure 3 The battery cell 20 further includes a pressure relief mechanism 70 , which is disposed on the housing and configured to be actuated and release the internal pressure of the battery cell 20 when the battery cell 20 thermally runs away.

[0256] The pressure relief mechanism 70 is disposed on the outer shell, and may be disposed on the end cover 21 or on the shell body 22 . Exemplarily, the pressure relief mechanism 70 is disposed on the end cover 21 .

[0257] The pressure relief mechanism 70 is configured to actuate and release the internal pressure of the battery cell 20 when the battery cell 20 is in thermal runaway, that is, when thermal runaway occurs inside the battery cell 20, the pressure relief mechanism 70 can be actuated and opened to release the gas generated inside the battery cell 20 due to thermal runaway. It should be noted that when thermal runaway occurs in the battery cell 20, the gas inside the shell of the battery cell 20 will increase rapidly to open the pressure relief mechanism 70 for pressure relief, while the gas generated inside the shell of the battery cell 20 during normal use can be discharged through the one-way valve 30 and / or the breathable membrane assembly 40, but the pressure relief mechanism 70 cannot be opened.

[0258] Optionally, the pressure relief mechanism 70 and the housing can be an integral structure or a separate structure. If the pressure relief mechanism 70 and the housing are an integral structure, the pressure relief mechanism 70 is an area on the housing where a weak structure is provided, such as an area on the housing where a notch is provided; if the pressure relief mechanism 70 and the housing are a separate structure, the pressure relief mechanism 70 can be connected to the housing by welding, hot melting, injection molding, or bonding. For example, in Figure 2-3 In the embodiment, the pressure relief mechanism 70 and the housing are separately arranged, and the pressure relief mechanism 70 is arranged on the end cover 21 of the housing. The pressure relief mechanism 70 can be a pressure relief component such as an explosion-proof valve, an explosion-proof disk, a pressure relief valve or a safety valve.

[0259] Exemplarily, the electrode terminal 25 and the pressure relief mechanism 70 are both arranged on the end cover 21. The battery cell 20 adopting this structure can save the space occupied by the battery cell 20. Of course, in other embodiments, the electrode terminal 25 and the pressure relief mechanism 70 can also be arranged on different walls of the outer shell. The battery cell 20 adopting this structure can make the electrode terminal 25 of the battery cell 20 used to output or input electrical energy and the pressure relief mechanism 70 used to release internal pressure stay away from each other to reduce the risk of using the battery cell 20. For example, the pressure relief mechanism 70 is arranged on the shell 22, and the electrode terminal 25 is arranged on the end cover 21.

[0260] By providing a one-way valve 30 and a breathable membrane assembly 40, when gas is generated inside the outer shell during normal use of the battery cell 20, it can be discharged to the outside of the outer shell through the one-way valve 30 and / or the breathable membrane assembly 40, so as to alleviate the phenomenon that the pressure relief mechanism 70 is prematurely actuated to relieve pressure before the thermal runaway of the battery cell 20 due to the increase of internal air pressure of the battery cell 20, thereby effectively improving the use stability of the battery cell 20, thereby improving the service life and use reliability of the battery cell 20.

[0261] In some embodiments, the one-way valve 30, the breathable membrane assembly 40 and the pressure relief mechanism 70 may be disposed on the same wall of the housing. For example, the one-way valve 30, the breathable membrane assembly 40 and the pressure relief mechanism 70 are all disposed on the end cover 21. The battery cell 20 adopting such a structure is conducive to saving the space occupied by the battery cell 20, so as to improve the energy density of the battery cell 20.

[0262] In some embodiments, the one-way valve 30, the breathable membrane assembly 40 and the pressure relief mechanism 70 may be arranged on different walls of the housing. For example, the one-way valve 30 and the breathable membrane assembly 40 are arranged on the housing 22, and the pressure relief mechanism 70 is arranged on the end cover 21. The battery cell 20 adopting this structure can reduce the mutual influence between the one-way valve 30, the breathable membrane assembly 40 and the pressure relief mechanism 70, and can be applied to different use environments. Preferably, the one-way valve 30, the breathable membrane assembly 40 and the pressure relief mechanism 70 are arranged on the wall at the top when the battery is placed to facilitate gas discharge.

[0263] In some embodiments, the actuation pressure of the pressure relief mechanism 70 is greater than the opening pressure of the one-way valve 30, that is, the pressure of the gas inside the shell to open the pressure relief mechanism 70 is greater than the pressure of the gas inside the shell to open the one-way valve 30. When the battery cell 20 has thermal runaway, the gas inside the shell of the battery cell 20 will increase rapidly to open the pressure relief mechanism 70 for pressure relief, while the gas generated inside the shell 21 of the battery cell 20 during normal use can open the one-way valve 30 when it reaches a threshold, but cannot open the pressure relief mechanism 70.

[0264] In some embodiments, the exhaust rate of the one-way valve 30 is less than the exhaust rate of the pressure relief mechanism 70 .

[0265] By setting the exhaust rate of the one-way valve 30 to be lower than the exhaust rate of the pressure relief mechanism 70, the phenomenon that the one-way valve 30 exhausts too quickly and the pressure relief mechanism 70 cannot be actuated to open can be alleviated when the battery cell 20 has thermal runaway. This allows the pressure relief mechanism 70 to actuate and stably discharge the internal pressure of the battery cell 20 when the battery cell 20 has thermal runaway, making it easier to relieve pressure, thereby helping to reduce the risk of fire and explosion of the battery cell 20 when the battery cell 20 has thermal runaway.

[0266] The end cover 21 is provided with a pressure relief hole 701, which is connected to the pressure relief mechanism 70. The diameter of the pressure relief hole 701 may be larger than the diameter of the first exhaust hole 291 connecting the one-way valve 30 and the breathable membrane assembly 40, so that the exhaust rate of the pressure relief mechanism 70 is greater than the exhaust rate of the one-way valve 30.

[0267] In some embodiments, the permeability rate of the breathable membrane 41 is 3-10 mL / day. It can be 3-4 mL / day, 5-8 mL / day, 9-10 mL / day. By setting the exhaust rate of the breathable membrane 41 to 3-10 mL / day, the phenomenon that the pressure relief mechanism 70 cannot be actuated and opened due to excessive exhaust can be alleviated when the battery cell 20 has thermal runaway, so that the pressure relief mechanism 70 can be actuated and stably discharge the internal pressure of the battery cell 20 when the battery cell 20 has thermal runaway, thereby helping to reduce the risk of fire and explosion of the battery cell 20 when the battery cell 20 has thermal runaway. At the same time, the airtightness of the system is also considered to prevent the exhaust rate from being too fast, resulting in poor airtightness, so as to maintain the airtightness of the battery system while exhausting the gas.

[0268] The test method for the exhaust rate of the breathable membrane 41 may be tested in accordance with GB / T1038-2000.

[0269] According to some embodiments of the present application, the opening pressure of the one-way valve is greater than or equal to 0.2MPa; optionally, greater than or equal to 0.4MPa; and optionally, greater than or equal to 0.8MPa. Exemplarily, the opening pressure of the valve core can be 0.20MPa, 0.25MPa, 0.30MPa, 0.35MPa, 0.40MPa, 0.45MPa, 0.50MPa, 0.55MPa, 0.60MPa, 0.65MPa, 0.70MPa, 0.75MPa, 0.80MPa, 0.90MPa, 1.00MPa.

[0270] The one-way valve opening pressure test method and principle can be tested based on the helium leakage standard, which is defined as follows: if the leakage rate is less than 10^-6Pa.m^3 / s, the system is considered to be sealed; if the leakage rate is greater than 10^-6Pa.m^3 / s, it indicates that there is gas leakage in the system.

[0271] During the test, the test chamber is sealed with a one-way valve, and helium is filled into the test chamber. The amount of helium in the environment of the test chamber is monitored with a helium detector. If helium is detected and the leakage rate is greater than 10^-6Pa.m^3 / s, it means that the test chamber is no longer sealed and helium is leaking out. The helium leakage rate is continuously monitored. When the leakage rate is greater than 10^-5Pa.m^3 / s, the one-way valve is determined to be open for deflation, and the pressure of the test chamber at this time is recorded as the opening pressure of the one-way valve.

[0272] According to some embodiments of the present application, when the breathable membrane assembly 40 and the one-way valve 30 are arranged in parallel, a breathable membrane 41 with a relatively low air permeability rate and a one-way valve 30 with a relatively high valve opening pressure can be selected for combination. In this way, because the breathable membrane 41 is always in a breathable state, if the air permeability rate is too high, the risk of external water vapor entering the battery cell 20 through the breathable membrane 41 will increase; because the present solution is also provided with a one-way valve 30, even if the air permeability rate of the breathable membrane assembly 40 is relatively low, when the internal pressure of the battery cell 20 is too high, the one-way valve 30 can be opened to quickly release air; therefore, a breathable membrane 41 with a relatively low air permeability rate can be selected, which can reduce the risk of external water vapor entering the battery cell 20 while meeting the air permeability requirements. And because the breathable membrane assembly 40 is always in a breathable state, the battery cell 20 will not be too large, and there is little need for the one-way valve 30 to open the valve too early, or in other words, when the internal pressure is relatively low, the breathable membrane assembly can achieve air permeability, so the one-way valve 30 opening pressure can be set larger.

[0273] In some embodiments, the battery cell 20 is an alkali metal battery, such as a sodium metal battery, a lithium metal battery, a magnesium metal battery, etc. The alkali metal battery is used in conjunction with the exhaust assembly to timely exhaust the gas generated by the alkali metal battery during normal operation, thereby increasing the service life of the alkali metal battery.

[0274] Among them, the electrode assembly 23 is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute the tabs. The positive tab and the negative tab can be located at one end of the main body or at both ends of the main body respectively. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0275] In one embodiment, the positive electrode sheet includes a positive electrode current collector and a positive electrode active layer disposed on at least one side of the positive electrode current collector, and the positive electrode active layer includes a positive electrode active material.

[0276] As an example, the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode active layer may be disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0277] In one embodiment, the positive electrode current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0278] In one embodiment, the positive electrode material includes one or more of a polyanion positive electrode material, a phosphate positive electrode material, a sulfate positive electrode material, a silicate positive electrode material, and a borate positive electrode material. For example, in the positive electrode active material of a sodium battery, the polyanion compound includes a compound based on phosphoric acid and fluorophosphoric acid. The phosphoric acid-based compound includes Na x1 Fe y1 P m1 O n1 , for example, sodium iron phosphate with higher capacity, sodium iron pyrophosphate with higher voltage platform. Polyanionic compounds include sodium vanadium trifluorophosphate Na 3 V 2 (PO 4 ) 2 F 3 、Sodium vanadium fluorophosphate NaVPO 4 F. Sodium vanadium phosphate Na 3 V 2 (PO 4 ) 3 、Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 、NaFePO 4 、Na 3 V 2 (PO 4 ) 3 One or more of the following. Prussian blue compounds are Na xMM(CN) 6 , wherein M, M are one or more of Fe, Mn, Co, Ni, Cu, Zn, Cr, Ti, V, Zr, Ce, and wherein 0<x≤2. The positive electrode active material in the lithium metal battery may include at least one of lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, or lithium iron manganese phosphate.

[0279] In one embodiment, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode active layer includes a negative electrode active material. In this embodiment, the battery cell is an ion battery. During the charge and discharge process of the battery, active ions (such as Li + 、Na + ) are intercalated / deintercalated in the negative electrode active material.

[0280] As an example, the negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode active layer may be disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0281] In one embodiment, the negative electrode current collector may be a metal foil or a composite current collector. For example, as the metal foil, a copper foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be obtained by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0282] In one embodiment, the negative electrode active material may include one or more of silicon-based materials, silicon-carbon materials, carbon materials, and selenium-based materials. Specifically, it includes one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based materials, and selenium-based materials. The silicon-based material can be selected from one or more of elemental silicon, silicon oxide compounds (such as silicon monoxide), silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The selenium-based material can be selected from one or more of elemental selenium, selenium oxide compounds, and selenium alloys.

[0283] In one embodiment, the negative electrode plate includes a negative electrode current collector and a carbonaceous coating disposed on at least one surface of the negative electrode current collector. In this embodiment, the battery cell is a metal battery, and during the battery charging and discharging process, active ions are deposited / stripped at the negative electrode plate. The metal battery can be an alkali metal battery, such as a lithium metal battery, a sodium metal battery, a potassium metal battery, a zinc metal battery, or an aluminum metal battery. This type of battery can also be called a "negative electrode-free battery". During the charging process, the active ions (such as Na +) is deposited on the negative electrode current collector to form sodium metal. The provision of the carbon-containing coating is conducive to more uniform metal deposition. The carbon-containing material includes one or more of conductive carbon, graphite, hard carbon, and carbon nanotubes.

[0284] In other embodiments, a conductive film layer may also be deposited on the negative electrode current collector. For example, alloy materials, titanium-based materials, active metals (such as sodium metal), carbon-based materials deposited with metals, composite materials containing metals, alloy materials containing metals, etc. The above alloy materials include but are not limited to sodium-tin alloys, sodium-germanium alloys, and sodium-antimony alloys. The above titanium-based materials include but are not limited to titanium dioxide, titanates, and titanium phosphates.

[0285] In one embodiment, the positive electrode active layer and the negative electrode active layer may further include a binder and a conductive agent. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0286] In one embodiment, the isolation membrane can be any known porous structure isolation membrane with good chemical stability and mechanical stability.

[0287] In one embodiment, the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation membrane can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0288] The electrolyte conducts ions between the positive electrode and the negative electrode. The electrolyte can be liquid, gel or all-solid.

[0289] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent. The electrolyte salt dissolves to form electrolyte ions, and conduction is achieved through the movement of the electrolyte ions in the electrolyte salt.

[0290] In one embodiment, in a sodium battery, the electrolyte salt comprises sodium hexafluorophosphate (NaPF 6 ), sodium bis(fluorosulfonyl)imide (NaFSI), sodium trifluoromethanesulfonate (CF 3 NaO 3 S), sodium sulfide (Na 2The lithium battery includes at least one lithium salt selected from the group consisting of lithium perchlorate, lithium hexafluoroarsenate, lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorooxalatoborate, lithium tetrafluoroborate, and lithium trifluoromethylsulfonate.

[0291] In one embodiment, the solvent includes one or more solvents selected from chain ethers, ethylene glycol dimethyl ether and its derivatives, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and cyclic ethers, including dimethyl ether (DME), diethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, 2,2,2,2-trifluoroethyl ether, ethylene glycol diethyl ether, triethylene glycol dimethyl ether, ethylene glycol dimethyl ether derivatives, methyl trifluoroethyl carbonate (FEMC), dioxolane (DOL), acetonitrile (AN), fluorobenzene, triethyl phosphate (TEP), sulfolane, 2-methyltetrahydrofuran, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylacetamide, etc.

[0292] In one embodiment, the electrolyte may further include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.

[0293] According to some embodiments of the present application, the present application further provides a battery 100, the battery 100 comprising a battery cell 20 of any of the above solutions. Fig.29 , Fig.29 1 is a schematic diagram of the exploded structure of a battery according to one or more embodiments. The battery 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is accommodated in the box body 10. Among them, the box body 10 is used to provide a storage space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, and the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space for accommodating the battery cell 20. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0294] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0295] Each battery cell 20 may be a secondary battery or a primary battery; specific examples thereof include all types of primary batteries or secondary batteries. For example, it may be a lithium battery, a sodium battery, a potassium battery, or other types of secondary batteries. A lithium secondary battery may include a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery. It may also be a lithium sulfur battery, a sodium ion battery, or a magnesium ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0296] In some embodiments, the battery may be an energy storage device, which includes an energy storage container, an energy storage cabinet, and the like.

[0297] According to some embodiments of the present application, the present application further provides an electric device, which includes a battery cell according to any of the above solutions, and the battery cell is used to provide electric energy for the electric device. The electric device can be any of the above devices or systems using the battery cell.

[0298] In some embodiments, the purpose of the electric equipment of the present application is not particularly limited, and it can be used for any electronic device known in the prior art. The battery disclosed in the embodiment of the present application can be used for electric equipment using the battery as a power source or various energy storage systems using the battery as an energy storage element. That is, a kind of electric equipment is provided, in some embodiments, the electric equipment of the present application can be used for, but not limited to, notebook computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini-discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, ships, spacecraft, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large-scale household batteries and lithium-ion capacitors, etc.

[0299] Electrical equipment can choose battery cells, battery modules or battery packs according to its usage requirements.

[0300] Please refer to Fig.30 , Fig.30 : is a schematic diagram of the structure of a vehicle according to one or more embodiments. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, the head or the tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for the starting, navigation and working power requirements of the vehicle 1000 during driving.

[0301] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0302] In the above embodiments, by providing a breathable membrane assembly, the battery cell can discharge internal gas through the breathable membrane in a sealed state, and the internal gas of the battery shell can be discharged to the outside of the shell in time, so that the air pressure inside the battery shell will not be too high, reducing the risk of the pressure relief mechanism opening the valve prematurely, which can greatly improve the life of the battery cell. One or more breathable membrane assemblies can be provided on a battery cell, and the location and manner of the provision of each breathable membrane assembly can be different, for example, one breathable membrane assembly is provided on the side of the end cover facing the inside of the battery shell, and one breathable membrane assembly is provided on the side of the end cover facing the outside of the battery shell. One breathable membrane assembly can be provided on the end cover, and the other breathable membrane assembly can be provided on the shell.

[0303] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: The housing has a wall portion, the wall portion has a first exhaust hole and a second exhaust hole arranged at intervals, the first exhaust hole and the second exhaust hole respectively communicate with the interior of the housing and the exterior of the housing; A breathable membrane assembly, comprising a breathable membrane, wherein the breathable membrane assembly is disposed on the wall portion and covers the second exhaust hole; A one-way valve comprises a valve body and a valve core, wherein the valve body has a valve cavity inside, and the valve body is provided with an air inlet and an air outlet, wherein the air inlet is used to connect the valve cavity with the inside of the shell, and the air outlet is used to connect the valve cavity with the outside of the shell; the valve core is arranged in the valve cavity, and the valve core is used to block the air inlet, and the valve core is configured to open the air inlet under the action of the gas inside the shell and release the gas inside the battery cell; the one-way valve is arranged on the wall portion, and the one-way valve covers the first exhaust hole.

2. The battery cell according to claim 1, characterized in that: The wall portion has an outer surface and an inner surface that are arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; The valve body is arranged on the outer surface, and at least a part of the valve body protrudes from the outer surface; At least a portion of the breathable membrane assembly is disposed on the outer surface.

3. The battery cell according to claim 1, characterized in that: The wall portion has an outer surface and an inner surface that are arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; The valve body is arranged on the outer surface, and at least a part of the valve body protrudes from the outer surface; The breathable membrane assembly is arranged on the inner surface of the wall portion.

4. The battery cell according to claim 1, characterized in that: The wall portion has an outer surface and an inner surface that are arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; The valve body is arranged on the outer surface, and at least a part of the valve body protrudes from the inner surface; The breathable membrane assembly is arranged on the inner surface.

5. The battery cell according to claim 1, characterized in that: The wall portion has an outer surface and an inner surface that are arranged opposite to each other, the outer surface is arranged toward the outside of the shell, and the inner surface is arranged toward the inside of the shell; The valve body is arranged on the outer surface, and at least a part of the valve body protrudes from the inner surface; At least a portion of the breathable membrane assembly is disposed on the outer surface.

6. The battery cell according to any one of claims 1 to 3, characterized in that: The valve body comprises: Valve seat; The valve cover comprises a cover top wall and a cover side wall connected to the cover top wall. The cover top wall, the cover side wall and the valve seat enclose the valve cavity. The valve seat is provided with the air inlet, and the valve cover is provided with the air outlet.

7. The battery cell according to claim 6, characterized in that: The valve seat has a first through hole penetrating the valve seat, and the air inlet is the first through hole.

8. The battery cell according to claim 6 or 7, characterized in that: The cover side wall has a second through hole penetrating the cover side wall, and the air outlet is the second through hole.

9. The battery cell according to claim 8, characterized in that: The second through hole extends to an end of the cover side wall in a direction away from the cover top wall.

10. The battery cell according to claim 9, characterized in that: There are a plurality of the second through holes, and the plurality of the second through holes are distributed at intervals in the circumferential direction of the cover side wall.

11. The battery cell according to any one of claims 6 to 10, characterized in that: A first guide column is protruding from the side of the cover top wall facing the valve cavity, and a third through hole is provided on the cover top wall that penetrates the cover top wall and the first guide column, or a third through hole is provided on the cover top wall that penetrates the cover top wall, and the air outlet is the third through hole.

12. The battery cell according to any one of claims 6 to 11, characterized in that: The valve cover also includes a flange wall, the cover side wall connects the cover top wall and the flange wall, the flange wall extends toward a side away from the valve cavity relative to the cover side wall, and the flange wall is connected to the valve seat.

13. The battery cell according to claim 12, characterized in that: A first recessed groove that is recessed relative to the surface of the valve seat is disposed on a side of the valve seat that faces the valve cover, and at least a portion of the flange wall is accommodated in the first recessed groove and connected to the valve seat.

14. The battery cell according to claim 13, characterized in that: The surface of the flange wall facing the cover top wall is flush with the surface of the valve seat facing the valve cover; or the surface of the flange wall facing the cover top wall is lower than the surface of the valve seat facing the valve cover.

15. The battery cell according to any one of claims 12 to 14, characterized in that: The flange wall is welded to the valve seat; wherein, in the circumferential direction of the cover side wall, at least a portion of a first weld mark between the flange wall and the valve seat is staggered with a second through hole on the cover side wall.

16. The battery cell according to claim 12, characterized in that: The outer circumferential surface of the valve seat is provided with a connecting protrusion, and the inner circumferential surface of the flange wall is provided with a receiving groove. The connecting protrusion is received in the receiving groove and connected to the flange wall.

17. The battery cell according to claim 16, characterized in that: The connecting protrusion is welded to the flange wall, wherein the flange wall has an upper surface and a lower surface arranged opposite to each other, the upper surface is arranged toward the top wall of the cover, and a second weld mark of the connecting protrusion and the flange wall is located on the lower surface of the flange wall.

18. The battery cell according to any one of claims 1 to 3, characterized in that: The valve body includes a valve cover, and the valve cover includes a cover top wall and a cover side wall connected to the cover top wall. The cover top wall, the cover side wall and the wall portion enclose the valve cavity. The first exhaust hole is the air inlet, and the valve cover is provided with the air outlet.

19. The battery cell according to claim 18, characterized in that: The side of the wall portion facing the outside of the shell is provided with a second groove recessed relative to the outer surface of the wall portion, and the valve cover also includes a flange wall, the cover side wall connects the cover top wall and the flange wall, the flange wall extends relative to the cover side wall toward the side away from the valve cavity, and at least a portion of the flange wall is accommodated in the second groove and connected to the wall portion.

20. The battery cell according to any one of claims 1, 4 and 5, characterized in that: The valve body comprises: A valve seat, comprising a seat bottom wall and a seat side wall connected to the seat bottom wall; The valve cover is arranged at one end of the valve seat away from the seat bottom wall. The valve cover, the seat side wall and the seat bottom wall are combined to form the valve cavity. The valve seat is provided with a fourth through hole, and the air inlet is the fourth through hole.

21. The battery cell according to claim 20, characterized in that: The valve cover has a fifth through hole penetrating the valve cover, and the air outlet includes the fifth through hole.

22. The battery cell according to claim 20 or 21, characterized in that: The valve cover is connected to the valve seat, and the air outlet includes a first exhaust gap formed between the valve cover and the valve seat.

23. The battery cell according to claim 20 or 21, characterized in that: The valve cover is connected to the wall portion, and the air outlet includes a second exhaust gap formed between the valve cover and the wall portion.

24. The battery cell according to any one of claims 1, 4 and 5, characterized in that: The valve body includes a valve seat, and the valve seat includes a seat bottom wall and a seat side wall connected to the seat bottom wall. The seat bottom wall, the seat side wall and the wall portion enclose the valve cavity. A fourth through hole is provided on the valve seat, the air inlet is the fourth through hole, and the air outlet is the first exhaust hole.

25. The battery cell according to any one of claims 1 to 24, characterized in that: The valve core comprises: An elastic member, disposed in the valve cavity; A blocking member is movably disposed in the valve cavity, and is used to block the air inlet under the action of the elastic member, and is used to open the air inlet under the action of the gas inside the shell.

26. The battery cell according to claim 25, characterized in that: The valve body comprises a valve cover, a first guide column is protrudingly provided on a side of the valve cover facing the valve cavity, and a portion of the elastic member is sleeved on the outer side of the first guide column.

27. The battery cell according to claim 26, characterized in that: The diameter of the first guide column is D1, and the inner diameter of the elastic member is D2, which satisfies the condition that 0 mm < D2 - D1 ≤ 5 mm.

28. The battery cell according to claim 26 or 27, characterized in that: A second guide column is protrudingly provided on one side of the blocking member facing the valve cover, and a portion of the elastic member is sleeved on the outer side of the second guide column.

29. The battery cell according to claim 28, characterized in that: The diameter of the second guide column is D3, and the inner diameter of the elastic member is D2, satisfying 0mm<D3-D1≤5mm.

30. The battery cell according to claim 28 or 29, characterized in that: In the axial direction of the elastic member, there is a gap between the end surface of the first guide column away from the valve cover and the end surface of the second guide column close to the valve cover.

31. The battery cell according to claim 30, characterized in that: The height H1 of the interval satisfies 0 mm<H1≤0.5 mm.

32. The battery cell according to any one of claims 26 to 31, characterized in that: In the axial direction of the valve cavity, two ends of the elastic member respectively abut against the valve cover and the sealing member, the distance between the first abutting surface of the valve cover and the second abutting surface of the sealing member is L1, and the physical length of the elastic member is L2, satisfying that L1>L2, wherein the physical length of the elastic member is the length occupied by the physical body of the elastic member after the elastic member is completely compacted.

33. The battery cell according to claim 32, characterized in that: L1-L2>0.5mm.

34. The battery cell according to claim 32 or 33, characterized in that: The elastic member is a spring, and the physical length of the elastic member L2=d1*n1+d2+d3, wherein d1 is the spring wire diameter, n1 is the maximum number of turns of the spring in the axial direction, d2 is the thickness of the outermost spring at one end of the spring, and d3 is the thickness of the outermost spring at the other end of the spring, d2≤d1, d3≤d1.

35. The battery cell according to any one of claims 26 to 34, characterized in that: A plurality of limiting protrusions are convexly disposed on the outer circumferential surface of the blocking member, and the plurality of limiting protrusions are arranged at intervals along the circumferential direction of the blocking member.

36. The battery cell according to any one of claims 26 to 35, characterized in that: The blocking member includes a pressing portion and a sealing portion. Two ends of the elastic member respectively abut against the valve cover and the pressing portion. The sealing portion is connected to a side of the pressing portion away from the valve cover. The sealing portion is used to block the air inlet.

37. The battery cell according to claim 36, characterized in that: The material of the sealing part includes EPDM, fluororubber or Teflon; and / or The elastic member is made of steel, iron or aluminum.

38. The battery cell according to any one of claims 1 to 37, characterized in that: The valve body includes a valve cover, and the valve cover includes a cover side wall. The cover side wall has a second through hole penetrating the cover side wall. The air outlet is the second through hole. Along the axial direction of the valve cavity, the sealing interface between the valve core and the valve seat is higher than or flush with the bottom wall of the second through hole.

39. The battery cell according to any one of claims 1-17, 20-23, 25-38, characterized in that: The first exhaust hole includes a through hole segment and a first hole segment, the through hole segment and the first hole segment are arranged along the thickness direction of the wall portion, the first hole segment is located on the side of the through hole segment away from the interior of the shell, the aperture of the first hole segment is larger than the aperture of the through hole segment, and the one-way valve is at least partially accommodated in the first hole segment.

40. The battery cell according to claim 39, characterized in that The first hole section comprises a hole side surface arranged circumferentially, and the outer peripheral surface of the valve cover / valve seat of the one-way valve is welded to the hole side surface.

41. The battery cell according to claim 40, characterized in that The valve seat is provided with a first step surface and a second step surface on one side facing the valve cover. The first step surface is closer to the valve cover than the second step surface. The outer peripheral surface of the second step is welded to the side surface of the hole.

42. The battery cell according to claim 40 or 41, characterized in that: The hole side surface matches with the outer peripheral surface of the valve cover / valve seat of the one-way valve, and the hole side surface and the outer peripheral surface of the valve cover / valve seat of the one-way valve are both arranged at an acute angle to the central axis of the first exhaust hole.

43. The battery cell according to any one of claims 40 to 42, characterized in that: A stress relief groove is arranged around the third weld mark between the valve cover / valve seat and the wall portion.

44. The battery cell according to claim 43, characterized in that A first stress relief groove is provided on a surface of the valve seat / valve cover facing the outside of the housing; and / or A second stress release groove is arranged on a surface of one side of the wall portion facing the outside of the housing.

45. The battery cell according to any one of claims 1 to 44, characterized in that: The breathable membrane assembly includes a breathable membrane and a connector, the breathable membrane is configured to allow gas inside the battery cell to pass through the breathable membrane and be discharged, the connector is provided with a first breathable hole, and the breathable membrane is provided on the connector and covers the first breathable hole.

46. ​​The battery cell according to claim 45, characterized in that The connecting member has a first annular table surface which is recessed relative to the surface of the connecting member. The first annular table surface is arranged around the first air permeable hole, and the air permeable membrane is arranged on the first annular table surface.

47. The battery cell according to claim 45 or 46, characterized in that: The breathable membrane assembly further comprises a backing member, which is arranged between the breathable membrane and the connecting member, and the air permeability rate of the backing member is greater than the air permeability rate of the breathable membrane.

48. The battery cell according to claim 47, characterized in that The connecting member has a second annular table surface which is recessed relative to the surface of the connecting member. The second annular table surface is arranged around the first air vent, and the backing member is arranged on the second annular table surface.

49. The battery cell according to any one of claims 45 to 48, characterized in that: The connecting piece is a metal piece.

50. The battery cell according to any one of claims 45 to 49, characterized in that: The breathable membrane is arranged on a side of the connecting member facing the inside of the shell, and the breathable membrane covers the first breathable hole.

51. The battery cell according to any one of claims 45 to 50, characterized in that: The connecting piece is connected to the wall portion by welding.

52. The battery cell according to claim 51, characterized in that A stress relief groove is arranged around the fourth weld mark between the connecting member and the wall portion.

53. The battery cell according to claim 51 or 52, characterized in that: A third stress relief groove is provided on the connecting member around the fourth weld mark between the connecting member and the wall portion; and / or A fourth stress release groove is arranged on the wall portion around the fourth weld mark between the connecting member and the wall portion.

54. The battery cell according to any one of claims 1 to 53, characterized in that: The wall portion has a first sunken platform that is recessed relative to the surface of the wall portion, the first sunken platform is arranged around the second exhaust hole, and the breathable membrane assembly is at least partially located on the first sunken platform.

55. The battery cell according to any one of claims 1 to 54, characterized in that: The battery cell further comprises: An insulating member is arranged on the side of the wall portion facing the inside of the shell; a third exhaust hole and a fourth exhaust hole are arranged on the insulating member at intervals and penetrate the insulating member, the third exhaust hole is connected to the first exhaust hole on the wall portion, and the fourth exhaust hole is connected to the second exhaust hole on the wall portion.

56. The battery cell according to any one of claims 1 to 55, characterized in that: The first exhaust hole is a liquid injection hole of the battery cell; or The first exhaust hole is spaced apart from the liquid injection hole of the battery cell.

57. The battery cell according to any one of claims 1 to 56, characterized in that: The housing comprises: A housing having an opening formed therein, wherein the housing is used to accommodate the electrode assembly; an end cap for closing the opening; Wherein, the end cover is the wall portion; or The housing includes the wall portion; or The wall portion is a wall located at the top of the housing when the battery cell is in a placed state.

58. The battery cell according to any one of claims 1 to 57, characterized in that: The first exhaust hole and the second exhaust hole are located on the same wall portion.

59. The battery cell according to any one of claims 1 to 58, characterized in that: The battery cell further includes a pressure relief mechanism, which is disposed on the housing and configured to actuate and release internal pressure of the battery cell when the battery cell thermally runs away, wherein an actuation pressure of the pressure relief mechanism is greater than an opening pressure of the one-way valve.

60. The battery cell according to claim 59, characterized in that The wall portion has a pressure relief hole, the pressure relief hole communicates the inside of the shell with the outside of the shell, and the pressure relief mechanism is arranged in the pressure relief hole; the aperture of the pressure relief hole is larger than the aperture of the first exhaust hole.

61. The battery cell according to claim 59 or 60, characterized in that: The exhaust rate of the one-way valve is lower than the exhaust rate of the pressure relief mechanism.

62. The battery cell according to any one of claims 1 to 61, characterized in that: The air permeability rate of the breathable membrane is 3-10 ml / day.

63. The battery cell according to any one of claims 1 to 62, characterized in that: The opening pressure of the one-way valve is greater than or equal to 0.2 MPa.

64. The battery cell according to any one of claims 1 to 63, characterized in that: The opening pressure of the one-way valve is greater than or equal to 0.4 MPa.

65. A battery, characterized in that: Comprising a battery cell as described in any one of claims 1-64.

66. An electrical device, characterized in that: The invention comprises a battery cell as described in any one of claims 1 to 64, wherein the battery cell is used to provide electrical energy.

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