CN217768563U - End cover assembly, battery monomer, battery and power consumption device - Google Patents

Abstract

The application relates to an end cover assembly, a battery monomer, a battery and an electric device. The end cover assembly comprises an end cover, a fixing piece, an electrode terminal and a sealing piece, the end cover is provided with a through hole, the fixing piece is connected to the end cover, the electrode terminal is arranged between the end cover and the fixing piece and comprises a main body part and a protruding part, the main body part is arranged opposite to the through hole, the protruding part surrounds the main body part and protrudes relative to the main body part along a first direction, and the first direction is perpendicular to the thickness direction of the end cover; the sealing piece comprises two sealing parts and a connecting part for connecting the two sealing parts, the projections of the two sealing parts on a plane perpendicular to the thickness direction of the end cover are at least partially overlapped, one sealing part of the two sealing parts is used for sealing and connecting the surface of the bulge part facing the end cover and the end cover, and the other sealing part is used for sealing and connecting the surface of the bulge part facing away from the end cover and the fixing part. The end cover assembly improves the permeation resistance of the electrode terminal to electrolyte and enhances the use reliability of the battery monomer.

Description

End cover assembly, battery monomer, battery and power consumption device

Technical Field

The application relates to the technical field of batteries, in particular to an end cover assembly, a battery monomer, a battery and an electric device.

Background

The battery cell is widely used in electronic devices such as a mobile phone, a notebook computer, a battery car, an electric airplane, an electric ship, an electric toy car, an electric toy ship, an electric toy airplane, an electric tool, and the like. The battery monomer can comprise a cadmium-nickel battery monomer, a hydrogen-nickel battery monomer, a lithium ion battery monomer, a secondary alkaline zinc-manganese battery monomer and the like.

In addition to improving the electrochemical performance of the battery cell, the reliability of the battery cell is a considerable problem in the development of battery technology. If the reliability of the battery cell cannot be guaranteed, the battery cell cannot be put into use. Therefore, how to improve the reliability of the battery cell is a technical problem to be solved urgently in the development process of the battery technology.

SUMMERY OF THE UTILITY MODEL

The application provides an end cover assembly, single battery, battery and power consumption device, aims at improving the single use reliability of battery.

In a first aspect, an embodiment of the present application provides an end cap assembly, which includes an end cap, a fixing member, an electrode terminal, and a sealing member, where the end cap has a through hole, the fixing member is connected to the end cap, the electrode terminal is disposed between the end cap and the fixing member, the electrode terminal includes a main body portion and a protruding portion, the main body portion is disposed opposite to the through hole, the protruding portion is disposed around the main body portion and protrudes in a first direction relative to the main body portion, and the first direction is perpendicular to a thickness direction of the end cap; the sealing element is connected between the electrode terminal and the fixing element and between the electrode terminal and the end cover in a sealing mode, the sealing element comprises two sealing parts and a connecting part for connecting the two sealing parts, the projections of the two sealing parts on a plane perpendicular to the thickness direction of the end cover are at least partially overlapped, one of the two sealing parts is connected with the surface, facing the end cover, of the protruding part in a sealing mode and the end cover in a sealing mode, and the other sealing part is connected with the surface, facing away from the end cover, of the protruding part in a sealing mode and the fixing element in a sealing mode.

From this, the end cover subassembly has two sealing parts, has formed twice seal structure on the thickness direction of end cover in other words for the osmotic resistance of electrode terminal to electrolyte can improve, has strengthened the sealed effect of end cover subassembly, has reduced the possibility of electrolyte seepage, thereby has alleviated the free performance decay of battery, has strengthened the free use reliability of battery.

In some embodiments, the surface of the sealing connection protrusion facing away from the end cap and the sealing portion of the fixture is a first portion; the sealing element further comprises a first extending part, the first extending part is connected to the first part and protrudes towards the direction departing from the end cover relative to the first part, in the first direction, one side, facing the electrode terminal, of the first extending part is abutted against the electrode terminal, and the other side of the first extending part is abutted against the fixing part.

Therefore, the first extending part is hermetically connected with the fixing part and the electrode terminal, the sealing performance between the fixing part and the electrode terminal can be further improved, and the sealing performance of the end cover assembly is improved.

In some embodiments, the surface of the fixing element facing away from the end cap does not extend beyond the end face of the first extension facing away from the first portion in the direction in which the first portion projects towards the direction facing away from the end cap.

Therefore, the first extending part can insulate and isolate the fixing part and the electrode terminal, the risk that the electrode terminal is damaged due to the fact that metal particles fall into a gap between the fixing part and the electrode terminal can be reduced, and the risk that the fixing part and the electrode terminal are in contact short circuit is reduced.

In some embodiments, the surface of the seal connecting projection facing the end cap and the seal portion of the end cap is the second portion; the sealing element further comprises a second extending part, the second extending part is connected to the second part and protrudes towards the direction departing from the protruding part relative to the second part, the second extending part protrudes into the through hole, and the second extending part is in contact with the hole wall of the through hole.

From this, when the end cover subassembly is used for battery monomer, the second extension can play insulating protective action to the end cover, reduces utmost point ear and end cover and takes place the risk of contact short circuit to improve battery monomer's security performance, and still be favorable to the assembly of sealing member to the position.

In some embodiments, the body portion projects into the through-hole, and the second extension sealingly connects at least part of the body portion with a wall of the through-hole.

Thus, the second extending portion seals at least a portion of the main body portion and the hole wall of the through hole, and the sealing performance between the end cap and the electrode terminal can be further improved, thereby improving the sealing performance of the end cap assembly.

In some embodiments, an end surface of the second extension facing away from the projection is flush with a surface of the end cap facing away from the fixture.

Therefore, the contact area between the second extending part and the hole wall of the through hole of the end cover is larger, and the insulating protection effect of the second extending part on the end cover is better.

In some embodiments, the end cap assembly further includes an insulating member, the insulating member includes an insulating main body portion connected to a side of the end cap facing away from the fixing member, and a protrusion portion connected to the insulating main body portion and protruding relative to the insulating main body portion and protruding into the through hole, the protrusion portion contacting an end portion of the second extension portion facing away from the second portion.

Therefore, the end cover assembly comprises the insulating piece, when the end cover assembly is used for a single battery, the insulating piece can play an insulating protection role on the end cover, the risk of short circuit between the electrode assembly and the end cover is reduced, and the safety performance of the single battery is improved; and, the tip that jut and second extension deviate from the second portion contacts, and jut and second extension structure together constitute the insulating protective action to the end cover, have further reduced electrode subassembly and the risk that the end cover takes place the short circuit, improve the free security performance of battery.

In some embodiments, a gap is formed between the protrusion and the wall of the through hole, and an end of the second extension facing away from the second portion is embedded in the gap.

Therefore, the protrusion portion has a squeezing effect on the second extending portion, so that not only can the stability of the second extending portion be enhanced, but also the sealing performance of the second extending portion on the end cover can be enhanced, and the sealing performance of the end cover assembly is improved.

In some embodiments, the dimension of the second extension part along the thickness direction of the end cover is A, the maximum thickness of the end cover is B, and A/B is more than or equal to 3/20 and less than or equal to 1/2.

Thereby, the second extension has a suitable length, and the assemblability thereof is improved while ensuring a suitable volume of the seal member.

In some embodiments, the end cap has a recess including a bottom wall and a side wall connected to and disposed around the bottom wall, the bottom wall being disposed around a through hole that extends through the bottom wall, at least one of the bottom wall and the side wall being connected to the fastener.

Therefore, the end cover can provide a certain sinking space for the electrode terminal, and the volume of the electrode terminal exceeding the end cover is reduced, so that the overall volume and space occupancy rate of the end cover assembly are reduced; and can reduce the connecting degree of difficulty of mounting and end cover, strengthen the joint strength of the two.

In some embodiments, the dimension of the recess in the thickness direction of the end cap is C, the maximum thickness of the end cap is B, and 1/4 ≦ C/B ≦ 3/5.

Therefore, the concave part has a proper depth ratio relative to the end cover, and the volume and the space occupancy rate of the end cover assembly can be reduced on the premise of ensuring the structural strength of the end cover.

In some embodiments, the fastener includes a connecting end disposed within the recess, the connecting end being connected to at least one of the bottom wall and the side wall; the end cover comprises a first surface and a second surface which are opposite to each other along the thickness direction of the end cover, wherein the first surface is the surface of the end cover close to the fixing piece, the second surface is the surface of the end cover facing away from the fixing piece, and the surface of the connecting end facing away from the bottom wall does not exceed the first surface along the direction that the second surface points to the first surface.

From this, the region that link and end cover contacted has good roughness, can improve the surface smoothness of end cover, is favorable to the assembly and the use of end cover.

In some embodiments, in the thickness direction of the end cover, the thickness of the fixing piece is D, the maximum thickness of the end cover is B, and D/B is more than or equal to 1/3 and less than or equal to 1/2.

From this, mounting and end cover have suitable thickness ratio, can be on the structural strength's of assurance mounting basis, do not occupy too much space simultaneously to reduce the volume of end cover subassembly.

In some embodiments, the connection portion sealingly connects the fixture and the projection.

Therefore, the sealing element can be used for sealing and connecting the fixing element and the electrode terminal, the sealing property between the fixing element and the electrode terminal is improved, and the sealing property of the end cover assembly is improved.

In a second aspect, the present application provides a battery cell comprising an end cap assembly according to any one of the embodiments of the first aspect of the present application.

In a third aspect, the present application provides a battery comprising a battery cell as in the second aspect of the present application.

In a fourth aspect, the present application provides an electric device comprising a battery as in the third aspect of the present application. The battery is used for providing electric energy.

Drawings

Features, advantages and technical effects of exemplary embodiments of the present application will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic illustration of a vehicle according to some embodiments of the present application;

fig. 2 is an exploded schematic view of a battery provided in some embodiments of the present application;

fig. 3 is a schematic structural view of a battery module according to some embodiments of the present disclosure;

fig. 4 is an exploded view of a battery cell provided in accordance with some embodiments of the present disclosure;

FIG. 5 is a schematic structural view of an end cap assembly provided in accordance with some embodiments of the present application;

FIG. 6 is an enlarged partial schematic view of the endcap assembly of FIG. 5 at M;

FIG. 7 is another enlarged partial schematic view of the endcap assembly of FIG. 5 at M;

FIG. 8 is a further enlarged partial schematic view at M of the endcap assembly of FIG. 5.

The drawings are not necessarily to scale.

The various reference numbers in the figures:

x, a first direction; y, the thickness direction of the end cover;

1. a battery cell;

10. an end cap assembly; 11. an end cap; 110. a through hole; 111. a recess; 111a, a bottom wall; 111b, side walls; 112. a first surface; 113. a second surface;

12. a fixing member; 120. a connecting end;

13. an electrode terminal; 131. a main body part; 132. a projection;

14. a seal member; 141. a sealing part; 141a, a first portion; 141b, a second part; 142. a connecting portion; 143. a first extension portion; 144. a second extension portion;

15. an insulating member; 151. an insulating main body portion; 152. a protrusion portion;

1a, a housing component; 20. a housing; 21. an accommodating chamber; 30. an electrode assembly;

2. a battery module;

3. a battery; 3a, a box body; 31. a first tank portion; 32. a second tank portion; 33. a box space;

4. a vehicle; 41. a controller; 42. a motor.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used in the description of the application in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "including" and "having," and any variations thereof, in the description and claims of this application and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and claims of this application or in the foregoing drawings are used for distinguishing between different elements and not for describing a particular sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the specification. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "attached" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The term "and/or" in this application is only one kind of association relationship describing the association object, and means that there may be three kinds of relationships, for example, a and/or b, and may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" in this application generally indicates that the former and latter related objects are in an "or" relationship.

In the embodiments of the present application, like reference numerals denote like parts, and a detailed description of the same parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only exemplary and should not constitute any limitation to the present application.

The appearances of "a plurality" in this application are intended to mean more than two (including two).

In the present application, the battery cell may include a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, a magnesium ion battery, or the like, which is not limited in the embodiments of the present application. The battery cell may be a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which is not limited in the embodiments of the present application. The battery cells are generally divided into three types in an encapsulation manner: the cylindrical battery monomer, the square battery monomer and the soft package battery monomer are not limited in the embodiment of the application.

Reference to a battery in embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack, etc. Batteries generally include a case for enclosing one or more battery cells. The box can avoid liquid or other foreign matters to influence the charging or discharging of battery monomer.

The battery cell includes an electrode assembly and an electrolyte, the electrode assembly including a positive electrode tab, a negative electrode tab, and a separator. The battery cell mainly depends on metal ions to move between the positive pole piece and the negative pole piece to work. The positive pole piece comprises a positive pole current collector and a positive pole active substance layer, and the positive pole active substance layer is coated on the surface of the positive pole current collector; the positive electrode current collector comprises a positive electrode current collecting portion and a positive electrode convex portion protruding out of the positive electrode current collecting portion, the positive electrode current collecting portion is coated with a positive electrode active substance layer, at least part of the positive electrode convex portion is not coated with the positive electrode active substance layer, and the positive electrode convex portion serves as a positive electrode lug. Taking a lithium ion battery as an example, the material of the positive electrode current collector may be aluminum, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, or the like. The negative pole piece comprises a negative pole current collector and a negative pole active substance layer, and the negative pole active substance layer is coated on the surface of the negative pole current collector; the negative current collector comprises a negative current collecting part and a negative convex part protruding out of the negative current collecting part, the negative current collecting part is coated with a negative active material layer, at least part of the negative convex part is not coated with the negative active material layer, and the negative convex part is used as a negative electrode tab. The material of the negative electrode current collector may be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon, silicon, or the like. In order to ensure that the fuse is not fused when a large current is passed, the number of the positive electrode tabs is multiple and the positive electrode tabs are stacked together, and the number of the negative electrode tabs is multiple and the negative electrode tabs are stacked together. The material of the spacer may be polypropylene (PP) or Polyethylene (PE). In addition, the electrode assembly may have a winding structure or a lamination structure, and the embodiment of the present application is not limited thereto.

The battery cell may also include a housing assembly including an end cap assembly and a housing. The case has a receiving chamber therein, which is a closed space provided by the case for the electrode assembly and the electrolyte, and the cap assembly may be used to close the receiving chamber.

The end cap assembly generally includes an end cap having a through hole, and an electrode terminal disposed at the through hole of the end cap and electrically connected to the electrode assembly in the accommodating cavity through the through hole to output electric energy of the electrode assembly. The electrode terminal also has the function of sealing the end cap through hole.

The inventor finds that the sealing performance of the end cover assembly of the conventional battery cell is often insufficient, the electrolyte is easy to leak out of the battery cell from the connecting area of the electrode terminal and the end cover, and the leakage of the electrolyte can cause the performance of the battery cell to be attenuated, thereby reducing the use reliability of the battery cell.

In order to solve the above technical problems, the inventor proposes an end cap assembly, which includes an end cap, a fixing member, an electrode terminal, and a sealing member, wherein the sealing member has two sealing portions and a connecting portion for connecting the sealing portions, one of the sealing portions is connected with the electrode terminal and the end cap in a sealing manner, the other sealing portion is connected with the fixing member and the electrode terminal in a sealing manner, the two sealing portions act together to form a two-way sealing structure, so that the permeation resistance of the electrode terminal to electrolyte is improved, the possibility of electrolyte leakage is reduced, the performance attenuation of a battery cell is relieved, and the use reliability of the battery cell is enhanced.

The technical scheme described in the embodiment of the application is suitable for the battery containing the battery cells and the electric device using the battery.

The electric device can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool and the like. The vehicle can be a fuel oil vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or a range-extended vehicle and the like; spacecraft include aircraft, rockets, space shuttles, spacecraft, and the like; the electric toys include stationary or mobile electric toys, such as game machines, electric car toys, electric ship toys, electric airplane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and electric power tools for railways, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiment of the present application does not specifically limit the above-mentioned electric devices.

For convenience of explanation, the following embodiments will be described with an electric device as an example of a vehicle.

Fig. 1 is a schematic structural diagram of a vehicle according to some embodiments of the present application.

As shown in fig. 1, a battery 3 is provided inside a vehicle 4, and the battery 3 may be provided at the bottom or the head or the tail of the vehicle 4. The battery 3 may be used for power supply of the vehicle 4, for example, the battery 3 may serve as an operation power source of the vehicle 4.

The vehicle 4 may also include a controller 41 and a motor 42, the controller 41 being configured to control the battery 3 to power the motor 42, for example, for start-up, navigation, and operational power requirements while the vehicle 4 is traveling.

In some embodiments of the present application, the battery 3 may not only serve as an operating power source for the vehicle 4, but also serve as a driving power source for the vehicle 4, instead of or in part replacing fuel or natural gas to provide driving power for the vehicle 4.

Fig. 2 is an exploded schematic view of a battery provided in some embodiments of the present application.

As shown in fig. 2, the battery 3 includes a case 3a and a battery cell (not shown in fig. 2) accommodated in the case 3a.

The case 3a is used for accommodating the battery cells, and the case 3a may have various structures. In some embodiments, the box body 3a may include a first box body portion 31 and a second box body portion 32, the first box body portion 31 and the second box body portion 32 cover each other, and the first box body portion 31 and the second box body portion 32 jointly define a box body space 33 for accommodating the battery cells. The second tank 32 may be a hollow structure with one open end, the first tank 31 may be a plate-like structure, and the first tank 31 covers the open side of the second tank 32 to form a tank 3a having a tank space 33; the first casing portion 31 and the second casing portion 32 may be both hollow structures with one side open, and the open side of the first casing portion 31 may cover the open side of the second casing portion 32 to form the casing 3a having the casing space 33. Of course, the first tank portion 31 and the second tank portion 32 may be various shapes, such as a cylinder, a rectangular parallelepiped, and the like.

In order to improve the sealing property after the first casing portion 31 and the second casing portion 32 are connected, a sealing member, such as a sealant or a gasket, may be provided between the first casing portion 31 and the second casing portion 32.

Assuming that the first box portion 31 covers the top of the second box portion 32, the first box portion 31 may also be referred to as an upper box cover, and the second box portion 32 may also be referred to as a lower box body.

In the battery 3, one or more battery cells may be provided. If the number of the battery monomers is multiple, the multiple battery monomers can be connected in series or in parallel or in series-parallel, and the series-parallel refers to that the multiple battery monomers are connected in series or in parallel. The plurality of battery monomers can be directly connected in series or in parallel or in series-parallel, and the whole formed by the plurality of battery monomers is accommodated in the box body 3a; of course, a plurality of battery cells may be connected in series or in parallel or in series-parallel to form the battery module 2, and a plurality of battery modules 2 may be connected in series or in parallel or in series-parallel to form a whole and accommodated in the case 3a.

Fig. 3 is a schematic structural diagram of a battery module according to some embodiments of the present disclosure. As shown in fig. 3, in some embodiments, there are a plurality of battery cells 1, and a plurality of battery cells 1 are connected in series or in parallel or in series-parallel to form a battery module 2. The plurality of battery modules 2 are connected in series or in parallel or in series-parallel to form a whole and are accommodated in the case.

The plurality of battery cells 1 in the battery module 2 may be electrically connected to each other through a bus member, so as to realize parallel connection, series connection, or parallel-series connection of the plurality of battery cells 1 in the battery module 2.

Fig. 4 is an exploded view of a battery cell according to some embodiments of the present disclosure.

As shown in fig. 4, the battery cell 1 provided in the embodiment of the present application includes an electrode assembly 30 and a case assembly 1a, and the electrode assembly 30 is accommodated in the case assembly 1 a.

The housing assembly 1a also serves to contain an electrolyte, such as an electrolyte. The housing component 1a can be of various structural forms.

In some embodiments, the case assembly 1a may include a case 20 and an end cap assembly 10, the case 20 is a hollow structure with one side open, and the end cap assembly 10 is covered on the opening of the case 20 and is hermetically connected to form a receiving cavity 21 for receiving the electrode assembly 30 and the electrolyte.

The housing 20 may be in various shapes, such as a cylinder, a rectangular parallelepiped, and the like. The shape of the case 20 may be determined according to the specific shape of the electrode assembly 30. For example, if the electrode assembly 30 is of a cylindrical structure, it may be optionally a cylindrical case; if the electrode assembly 30 has a rectangular parallelepiped structure, a rectangular parallelepiped case may be used.

In some embodiments, the end cap assembly 10 includes an end cap 11, and the end cap 11 covers the opening of the housing 20. The end cap 11 may have various structures, for example, the end cap 11 has a plate-shaped structure, a hollow structure with one end open, and the like. Illustratively, in fig. 4, the housing 20 has a rectangular parallelepiped structure, the end cap 11 has a plate-like structure, and the end cap 11 covers an opening at the top of the housing 20.

The end cap 11 may be made of an insulating material (e.g., plastic) or a conductive material (e.g., metal). When the end cap 11 is made of a metal material, the end cap assembly 10 may further include an insulating member at a side of the end cap 11 facing the electrode assembly 30 to insulate and separate the end cap 11 from the electrode assembly 30.

In some embodiments, the end cap assembly 10 may further include an electrode terminal 13, the electrode terminal 13 being mounted on the end cap 11. The two electrode terminals 13 are defined as a positive electrode terminal and a negative electrode terminal 13, and the positive electrode terminal and the negative electrode terminal are electrically connected to the electrode assembly 30 to output electric power generated from the electrode assembly 30.

In other embodiments, the housing assembly 1a may have other structures, for example, the housing assembly 1a includes a casing 20 and two end cap assemblies 10, the casing 20 is a hollow structure with two opposite open sides, and one end cap assembly 10 is correspondingly covered on one open side of the casing 20 and is connected in a sealing manner to form a containing cavity 21 for containing the electrode assembly 30 and the electrolyte. In this structure, two electrode terminals 13 may be provided on one end cap assembly 10, and the electrode terminals 13 may not be provided on the other end cap assembly 10, or one electrode terminal 13 may be provided on each of the two end cap assemblies 10.

In the battery cell 1, the electrode assembly 30 housed in the case assembly 1a may be one or more. Illustratively, in fig. 4, there are four electrode assemblies 30.

FIG. 5 is a schematic structural view of an end cap assembly provided in accordance with certain embodiments of the present application; FIG. 6 is an enlarged partial schematic view of the endcap assembly of FIG. 5 at M.

As shown in fig. 5 and 6, in some embodiments, the end cap assembly 10 includes an end cap 11, a fixing member 12, an electrode terminal 13, and a sealing member 14, the end cap 11 has a through hole 110, the fixing member 12 is connected to the end cap 11, the electrode terminal 13 is disposed between the end cap 11 and the fixing member 12, the electrode terminal 13 includes a main body portion 131 and a protruding portion 132, the main body portion 131 is disposed opposite to the through hole 110, the protruding portion 132 is disposed around the main body portion 131 and protrudes in a first direction X relative to the main body portion 131, wherein the first direction X is perpendicular to a thickness direction Y of the end cap 11; the sealing member 14 is connected between the electrode terminal 13 and the fixing member 12 and the end cap 11 in a sealing manner, the sealing member 14 includes two sealing portions 141 and a connecting portion 142 connecting the two sealing portions 141, projections of the two sealing portions 141 on a plane perpendicular to a thickness direction Y of the end cap 11 at least partially overlap, one of the two sealing portions 141 seals a surface of the connecting protrusion 132 facing the end cap 11 and the end cap 11, and the other of the two sealing portions 141 seals a surface of the connecting protrusion 132 facing away from the end cap 11 and the fixing member 12.

The end cap 11 is a main structure of the end cap assembly 10, the fixing member 12 is connected to the end cap 11, and the fixing member 12 is used for fixing the electrode terminal 13. The fixing member 12 and the end cap 11 can be connected in various ways, such as directly, for example, by welding, etc., or indirectly, for example, by using an adhesive. When the end cap 11 and the fixing member 12 are welded, they are made of metal, such as aluminum, aluminum alloy, stainless steel, etc., the end cap 11 and the fixing member 12 may be made of the same material, for example, they are made of aluminum alloy, which has the advantages of light weight and high strength; the two material also can be different, for example, the end cover 11 adopts the aluminum alloy material, and mounting 12 adopts the steel, and steel mounting 12 intensity is higher, and the resistance to deformation ability is stronger, and fixed effect is also better. Of course, the end cap 11 and the fixing member 12 may also be made of a non-metal material, such as a plastic material, and one of the end cap 11 and the fixing member 12 may also be made of a metal material and the other is made of a non-metal material, which is not limited in this application.

The fixing member 12 is used to fix the electrode terminal 13 on the end cover 11, and the fixing form may be various, for example, one end of the fixing member 12 may be fixedly connected to the end cover 11, and the other end may be fixedly connected to the electrode terminal 13, or one end of the fixing member 12 may be fixedly connected to the end cover 11, and the other end is crimped to a side of the electrode terminal 13 away from the end cover 11. It should be noted that the fixing member 12 is insulated from the electrode terminal 13 to reduce the risk of short circuit of the electrode terminal 13 through electrical conduction between the fixing member 12 and the end cap 11. If the fixing member 12 is made of a non-conductive material, it can directly contact with the electrode terminal 13, and if the fixing member 12 is made of a conductive material, an insulating member is disposed between the fixing member 12 and the electrode terminal 13, and the insulating member can prevent the electrode terminal 13 from directly conducting with the fixing member 12.

The fixing member 12 may have various structural forms, for example, the cross-sectional shape of the fixing member 12 in the thickness direction Y of the end cap 11 may be substantially Z-shaped (see fig. 6); alternatively, the fixing member 12 has a plate-like structure bent vertically, that is, the cross-sectional shape of the fixing member 12 is an inverted L shape along the thickness direction Y of the end cap 11.

The electrode terminal 13 is disposed between the end cap 11 and the fixing member 12, and includes a main body portion 131 and a protrusion 132, the main body portion 131 being disposed opposite to the through hole 110, which may be used for connection with a tab. The main body 131 may have various structures, for example, the main body 131 may be located on one side of the end cap 11, and does not extend into the through hole 110; or a part of the main body part 131 is located at one side of the end cover 11 and a part is located in the through hole 110, and at this time, the part of the main body part 131 extending into the through hole 110 is insulated from the end cover 11, and there may be various insulation manners, for example, an insulation member may be provided between the two to reduce the risk of contact short circuit between the main body part 131 and the end cover 11.

The protrusion 132 is disposed around the body part 131 and protrudes in the first direction X with respect to the body part 131, and the protrusion 132 is disposed opposite to the end cap 11 and supports the overall structure of the electrode terminal 13. The protrusion 132 and the body 131 together form the electrode terminal 13, and may be formed as two separate structures integrally connected to each other or integrally formed. Alternatively, the electrode terminal 13 is an integrally molded structure, and the integrally molded structure has better structural strength.

The sealing member 14 is hermetically connected between the electrode terminal 13 and the fixture 12 and the end cap 11, that is, the sealing member 14 is disposed between the fixture 12 and the electrode terminal 13, and the sealing member 14 may hermetically connect the electrode terminal 13 and the end cap 11 or may hermetically connect the electrode terminal 13 and the fixture 12. The seal 14 is made of an insulating material, such as rubber or teflon, as is common.

The sealing member 14 includes two sealing portions 141, and projections of the two sealing portions 141 on a plane perpendicular to the thickness direction Y of the end cap 11 at least partially overlap, that is, projections of the two sealing portions 141 on a plane perpendicular to the thickness direction Y of the end cap 11 may completely overlap or may only partially overlap. One of the two sealing portions 141 seals the surface of the connecting projection 132 facing the end cap 11 and the end cap 11, and the other seals the surface of the connecting projection 132 facing away from the end cap 11 and the fixing member 12. In this application, sealing 141 has the effect of insulation in addition to the sealing effect, and two sealing 141 not only can make between bulge 132 and the end cover 11 insulating, can also make between bulge 132 and the mounting 12 insulating, and from this, sealing 141 that has the effect of insulation has further reduced the risk of taking place the short circuit between end cover 11 and the electrode terminal 13, when end cover assembly 10 is used for the battery monomer, has improved the free security performance of battery.

According to the end cap assembly 10 of some embodiments of the present application, it includes two sealing portions 141, one of the two sealing portions 141 seals the surface of the connecting protrusion 132 facing the end cap 11 and the end cap 11, and the other seals the surface of the connecting protrusion 132 facing away from the end cap 11 and the fixing member 12, which is equivalent to forming two sealing structures in the thickness direction Y of the end cap 11, so as to improve the permeation resistance of the electrode terminal 13 to the electrolyte, enhance the sealing effect of the end cap assembly 10, reduce the possibility of electrolyte leakage, thereby alleviating the performance attenuation of the battery cell, and enhancing the use reliability of the battery cell.

FIG. 7 is another enlarged partial view of the endcap assembly of FIG. 5 at M.

As shown in fig. 5, 6 and 7, in some embodiments, the surface of the sealing connecting projection 132 facing away from the end cap 11 and the sealing portion 141 of the fixing member 12 are first portions 141a; the sealing member 14 further includes a first extending portion 143, the first extending portion 143 is connected to the first portion 141a and protrudes relative to the first portion 141a in a direction away from the end cap 11, and in the first direction X, one side of the first extending portion 143 facing the electrode terminal 13 abuts against the electrode terminal 13, and the other side abuts against the fixing member 12.

The sealing member 14 further includes a first extension portion 143, and the first extension portion 143 is a part of the sealing member 14, and may be connected to the first portion 141a as a separate structural body or may be integrally formed with the first portion 141 a. The first extension part 143 faces the electrode terminal 13, and the other side faces the fixing part 12, and the contact means that the first extension part 143 and the electrode terminal 13 are not only in contact with each other, but also have mutual acting force, that is, one side of the first extension part 143 facing the electrode terminal 13 is pressed by the electrode terminal 13, and the other side is pressed by the fixing part 12, so that the first extension part 143 is pressed to generate elastic potential energy toward the fixing part 12 and the electrode terminal 13, and thus the first extension part 143 can hermetically connect the fixing part 12 and the electrode terminal 13.

The first extension 143 hermetically connects the fixing member 12 and the electrode terminal 13, which can further improve the sealing between the fixing member 12 and the electrode terminal 13, thereby improving the sealing of the end cap assembly 10 and reducing the possibility of electrolyte leakage.

As shown in fig. 7, in some embodiments, in the direction in which the first portion 141a protrudes toward the direction away from the end cap 11, the surface of the fixing member 12 facing away from the end cap 11 does not exceed the end surface of the first extension 143 facing away from the first portion 141 a.

In the present embodiment, the direction in which the first portion 141a protrudes toward the direction away from the end cap 11 can be understood as the direction from the end cap 11 toward the fixing piece 12; in this direction, the surface of the fixing member 12 facing away from the end cover 11 does not exceed the end surface of the first extending portion 143 facing away from the first portion 141a, i.e., there may be various structural forms between the first extending portion 143 and the fixing member 12.

In some examples, an end surface of the first extending portion 143 facing away from the first portion 141a is flush with a surface of the fixing member 12 facing away from the end cap 11, in this case, the first extending portion 143 may insulate and isolate the fixing member 12 from the electrode terminal 13, and may also reduce a risk of damage to the electrode terminal 13 due to metal particles falling into a gap between the fixing member 12 and the electrode terminal 13, and when the fixing member 12 is made of a conductive material, may also reduce a risk of a contact short circuit between the fixing member 12 and the electrode terminal 13 due to metal particles falling into the gap. And the permeation resistance of the electrolyte can be further increased, and the risk that the electrolyte is leaked out of the battery monomer is reduced.

In other examples, the end surface of the first extension 143 facing away from the first portion 141a exceeds the surface of the fixing member 12 facing away from the end cap 11, so that the risk of short circuit between the fixing member 12 and the electrode terminal 13 due to metal particles falling can be further reduced.

As shown in fig. 7, in some embodiments, the surface of the seal connecting projection 132 facing the end cap 11 and the seal portion 141 of the end cap 11 are second portions 141b; the sealing member 14 further includes a second extending portion 144, the second extending portion 144 is connected to the second portion 141b and protrudes relative to the second portion 141b in a direction away from the protruding portion 132, and protrudes into the through hole 110, and the second extending portion 144 contacts with a hole wall of the through hole 110.

The sealing member 14 further includes a second extending portion 144, and the second extending portion 144 is a part of the sealing member 14, and may be connected to the second portion 141b as a separate structure or may be integrally formed with the second portion 141 b.

The second extending portion 144 protrudes in a direction away from the protruding portion 132 relative to the second portion 141b, protrudes into the through hole 110, and contacts with a hole wall of the through hole 110. When the end cover assembly is used for a single battery, the tab in the single battery can be electrically connected with the electrode terminal 13 through the through hole 110, and the second extension part 144 can play an insulating protection role on the end cover 11, so that the risk of contact short circuit between the tab and the end cover 11 is reduced, and the safety performance of the single battery is improved. And the second extension 144 projects into the through bore 110, also facilitating the assembly of the seal 14 into place.

The second extension 144 protrudes into the through hole 110, and there are various structures between the second extension 144 and the end cap 11.

In some examples, the surface of the end cap 11 facing away from the fastener 12 exceeds the end surface of the second extension 144 facing away from the projection 132.

In other examples, the end surface of the second extending portion 144 facing away from the protrusion 132 is flush with the surface of the end cap 11 facing away from the fixing member 12, in which case, the contact area of the second extending portion 144 with the hole wall of the through hole 110 of the end cap 11 is larger, and the insulation protection effect on the end cap 11 is better.

As shown in fig. 7, in some embodiments, the main body portion 131 protrudes into the through-hole 110, and the second extension 144 sealingly connects at least a portion of the main body portion 131 with a wall of the through-hole 110.

The second extending portion 144 sealingly connects at least a portion of the main body portion 131 and the hole wall of the through hole 110, and can further improve the sealing property between the end cap 11 and the electrode terminal 13, thereby improving the sealing property of the end cap assembly.

FIG. 8 is a further enlarged partial schematic view at M of the endcap assembly of FIG. 5.

As shown in fig. 8, in some embodiments, the end cap assembly further includes an insulating member 15, the insulating member 15 includes an insulating main body portion 151 and a protrusion portion 152, the insulating main body portion 151 is connected to a side of the end cap 11 facing away from the fixing member 12, the protrusion portion 152 is connected with the insulating main body portion 151 and protrudes relative to the insulating main body portion 151 and protrudes into the through hole 110, and the protrusion portion 152 is in contact with an end portion of the second extension portion 144 facing away from the second portion 141 b.

The insulating member 15 is made of an insulating material, which may be a polypropylene (PP) material or a Polyethylene (PE) material. The insulating member 15 is connected to a side of the end cover 11 away from the fixing member 12, and the arrangement manner may be various, for example, the insulating member 15 may be connected to the end cover 11, specifically, a plurality of fasteners may be arranged on the insulating member 15, the insulating member 15 is fastened to the end cover 11, or the insulating member 15 is adhered to the end cover 11 by using an adhesive, and the like; of course, the insulating element 15 may not be directly connected to the end cap 11.

Set up insulating part 15, when the end cover subassembly is used for the battery monomer, insulating part 15 can play insulating protective action to end cover 11, reduces electrode subassembly and end cover 11 and takes place the risk of short circuit, improves the free security performance of battery.

The insulating member 15 includes an insulating main body portion 151 and a protrusion portion 152, and the insulating main body portion 151, which is a main structure of the insulating member 15, may have various shapes such as a rectangular, square, or circular plate-shaped structure, or other irregular shapes. The shape of the insulating member 15 may be set according to the shape of the end cap 11, for example, if the end cap 11 has a rectangular plate-like structure, the insulating member 15 may also have a rectangular plate-like structure.

The protrusion 152 protrudes from the insulating main body 151 and into the through hole 110, and the protrusion 152 contacts with an end of the second extension 144 away from the second portion 141b, and may have various forms.

In some examples, the end of the protruding portion 152 facing away from the insulating main body portion 151 and the end of the second extending portion 144 facing away from the second portion 141b just contact, and at this time, the protruding portion 152 and the second extending portion 144 only contact and do not have a force effect, and the protruding portion 152 and the second extending portion 144 together form an insulating protection effect on the end cap 11, so that the risk of short circuit between the electrode assembly and the end cap 11 is further reduced, and the safety performance of the battery cell is improved.

In other examples, as shown in fig. 8, a gap is formed between the protrusion 152 and the hole wall of the through hole 110, and an end of the second extension 144 facing away from the second portion 141b is embedded in the gap. In this case, the protrusion 152 has a pressing effect on the second extending portion 144, which not only can enhance the stability of the second extending portion 144 and prevent it from shifting or shaking, but also can enhance the sealing performance of the second extending portion 144 on the end cover 11, thereby improving the sealing performance of the end cover assembly.

As shown in FIG. 8, in some embodiments, the dimension of the second extension portion 144 in the thickness direction of the end cap 11 is A, the maximum thickness of the end cap 11 is B, and 3/20 ≦ A/B ≦ 1/2.

When the battery cell satisfies the above relationship, insulation between the end cap 11 and the main body portion 131 can be ensured, and the second extending portion 144 does not substantially interfere with the members inside the battery cell.

As shown in fig. 8, in some embodiments, the end cap 11 has a recess 111, the recess 111 includes a bottom wall 111a and a side wall 111b connected to the bottom wall 111a and disposed around the bottom wall 111a, the bottom wall 111a is disposed around the through hole 110, the through hole 110 penetrates the bottom wall 111a, and at least one of the bottom wall 111a and the side wall 111b is connected to the fixing member 12.

The end cap 11 is provided with the concave part 111, the bottom wall 111a of the concave part 111 is arranged around the through hole 110, and the through hole 110 penetrates through the bottom wall 111a, so that a certain sinking space is provided for the electrode terminal 13 on the end cap 11, the volume of the electrode terminal 13 exceeding the end cap 11 is reduced, and the volume and the space occupancy rate of the whole end cap assembly are reduced. Moreover, the concave portion 111 facilitates the installation and positioning of the fixing member 12, and the fixing member 12 is disposed to be connected to at least one of the bottom wall 111a and the side wall 111b of the concave portion 111, so that the difficulty in connecting the fixing member 12 and the end cover 11 can be reduced, and the connection strength between the fixing member 12 and the end cover 11 can be enhanced.

At least one of the bottom wall 111a and the side wall 111b is connected to the fixing member 12, that is, it is understood that the fixing member 12 may be connected to only the bottom wall 111a, or the fixing member 12 is connected to only the side wall 111b, or the fixing member 12 is connected to both the bottom wall 111a and the side wall 111 b.

As shown in FIG. 8, in some embodiments, the recess 111 has a dimension C in the thickness direction Y of the end cap 11, the maximum thickness of the end cap 11 is B, and 1/4 ≦ C/B ≦ 3/5. By providing the recess 111 with a suitable depth ratio relative to the end cover 11, the volume and space occupancy rate of the end cover assembly can be reduced while ensuring the structural strength of the end cover 11.

As shown in fig. 8, in some embodiments, the fixing member 12 includes a connecting end 120 disposed in the recess 111, the connecting end 120 being connected to at least one of the bottom wall 111a and the side wall 111 b; the end cap 11 includes a first surface 112 and a second surface 113 opposite to each other along the thickness direction Y thereof, wherein the first surface 112 is a surface of the end cap 11 close to the fixing member 12, the second surface 113 is a surface of the end cap 11 facing away from the fixing member 12, and a surface of the connecting end 120 facing away from the bottom wall 111a does not exceed the first surface 112 in a direction along the second surface 113 toward the first surface 112. The direction along the second surface 113 directed to the first surface 112 is parallel to the thickness direction X.

The connection end 120 is connected to at least one of the bottom wall 111a and the side wall 111b, i.e., it is understood that the connection end 120 may be connected to only the bottom wall 111a, or the connection end 120 is connected to only the side wall 111b, or the connection end 120 is connected to both the bottom wall 111a and the side wall 111 b.

In a direction in which the second surface 113 points to the first surface 112, a surface of the connecting end 120 facing away from the bottom wall 111a does not extend beyond the first surface 112, i.e., a surface of the connecting end 120 facing away from the bottom wall 111a may be lower than the first surface 112 or may be flush with the first surface 112. The advantage of this arrangement is that the flatness of the contact area between the connecting end 120 and the end cap 11 can be improved, that is, the surface flatness of the end cap 11 can be improved, which is beneficial to the assembly and use of the end cap 11. And when the fixing member 12 is assembled to the end cover 11, the risk of interference to other components due to the excessive assembly space caused by the excessively high height of the fixing member 12 can be reduced.

As shown in FIG. 8, in some embodiments, the thickness of the fixing member 12 is D, the maximum thickness of the end cap 11 is B, and D/B is greater than or equal to 1/3 and less than or equal to 1/2. The thickness ratio of the fixing piece 12 and the end cover 11 is reasonably arranged, so that the structural strength of the fixing piece 12 can be guaranteed, meanwhile, excessive space is not occupied, and the size of the end cover assembly is reduced.

In some embodiments, the connecting portion 142 sealingly connects the anchor 12 and the projection 132.

The connection part 142 hermetically connects the fixing member 12 and the protrusion 132, which can further improve the sealability between the fixing member 12 and the electrode terminal 13, thereby improving the sealability of the cap assembly; further increasing the permeation resistance of the electrolyte and improving the use reliability of the single battery

As shown in fig. 5 to 7, as an embodiment of the present application, the end cap assembly 10 includes an end cap 11, a fixing member 12, an electrode terminal 13, and a sealing member 14, the end cap 11 has a through hole 110, the fixing member 12 is connected to the end cap 11, the electrode terminal 13 is disposed between the end cap 11 and the fixing member 12, the electrode terminal 13 includes a main body portion 131 and a protruding portion 132, the main body portion 131 is disposed opposite to the through hole 110, and the protruding portion 132 is disposed around the main body portion 131 and protrudes in a first direction X relative to the main body portion 131, wherein the first direction X is perpendicular to a thickness direction Y of the end cap 11; the sealing member 14 includes a first portion 141a, a second portion 141b, and a connecting portion 142, the first portion 141a sealingly connects the surface of the protruding portion 132 facing away from the end cap 11 and the fixing member 12, the second portion 141b sealingly connects the surface of the protruding portion 132 facing the end cap 11 and the end cap 11, the connecting portion 142 connects the first portion 141a and the second portion 141b, and projections of the first portion 141a and the second portion 141b on a plane perpendicular to the thickness direction Y of the end cap 11 at least partially overlap.

The end cover assembly 10 of the embodiment of the application comprises a first portion 141a and a second portion 141b, the second portion 141b is connected with the surface, facing the end cover 11, of the protruding portion 132 in a sealing mode and the end cover 11, the first portion 141a is connected with the surface, facing away from the end cover 11, of the protruding portion 132 in a sealing mode and the fixing piece 12 in a sealing mode, two sealing structures are equivalently formed in the thickness direction Y of the end cover 11, the permeation resistance of the electrode terminals 13 to electrolyte is improved, the overall sealing performance of the end cover assembly 10 is enhanced, the possibility of electrolyte leakage is reduced, the performance attenuation of single batteries is relieved, and the use reliability of the single batteries is enhanced.

While the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the present application, and in particular, features shown in the various embodiments may be combined in any manner as long as there is no structural conflict. The present application is not intended to be limited to the particular embodiments disclosed herein, but rather to cover all embodiments falling within the scope of the appended claims.

Claims (17)

1. An end cap assembly, comprising:

an end cap having a through hole;

the fixing piece is connected to the end cover;

the electrode terminal is arranged between the end cover and the fixing piece and comprises a main body part and a protruding part, the main body part is arranged opposite to the through hole, the protruding part is arranged around the main body part and protrudes relative to the main body part along a first direction, and the first direction is perpendicular to the thickness direction of the end cover; and

the sealing element is connected between the electrode terminal and the fixing element and between the electrode terminal and the end cover in a sealing mode, the sealing element comprises two sealing parts and a connecting part for connecting the two sealing parts, the projections of the two sealing parts on a plane perpendicular to the thickness direction of the end cover are at least partially overlapped, one of the two sealing parts is connected with the surface, facing the end cover, of the bulge in a sealing mode, and the other sealing part is connected with the surface, facing away from the end cover, of the bulge in a sealing mode, of the sealing part and the fixing element in a sealing mode.

2. An end cap assembly according to claim 1, wherein the sealing portion sealingly connecting the surface of the projection facing away from the end cap and the retainer is a first portion;

the sealing element further comprises a first extending portion, the first extending portion is connected to the first portion and protrudes relative to the first portion in a direction away from the end cover, in the first direction, one side, facing the electrode terminal, of the first extending portion abuts against the electrode terminal, and the other side of the first extending portion abuts against the fixing piece.

3. The end cap assembly of claim 2,

in the direction that the first part is protruded towards the direction departing from the end cover, the surface of the fixing part departing from the end cover does not exceed the end surface of the first extension part departing from the first part.

4. An end cap assembly according to claim 1, wherein the sealing portion sealingly connecting the surface of the projection facing the end cap and the end cap is a second portion;

the sealing element further comprises a second extending part, the second extending part is connected to the second part, protrudes relative to the second part in a direction away from the protruding part and protrudes into the through hole, and the second extending part is in contact with the hole wall of the through hole.

5. The end cap assembly of claim 4, wherein the body portion projects into the through-hole, and the second extension sealingly connects at least a portion of the body portion with a wall of the through-hole.

6. An end cap assembly according to claim 4, wherein an end surface of the second extension facing away from the tab is flush with a surface of the end cap facing away from the fixture.

7. The end cap assembly of claim 4, further comprising an insulator, the insulator comprising:

the insulating main body part is connected to one side, away from the fixing part, of the end cover;

and the protrusion part is connected with the insulating main body part, protrudes relative to the insulating main body part and protrudes into the through hole, and the protrusion part is in contact with the end part of the second extension part, which is deviated from the second part.

8. The end cap assembly of claim 7, wherein a gap is formed between the protrusion and the wall of the through hole, and an end of the second extension facing away from the second portion is embedded in the gap.

9. The end cap assembly of claim 4, wherein the dimension of the second extension in the thickness direction of the end cap is A, the maximum thickness of the end cap is B, and 3/20A/B is 1/2.

10. An end cap assembly according to claim 1, wherein the end cap has a recess including a bottom wall and a side wall connected to and disposed around the bottom wall, the bottom wall being disposed around the through hole, the through hole extending through the bottom wall, at least one of the bottom wall and the side wall being connected to the fastener.

11. An end cap assembly according to claim 10, wherein the recess has a dimension C in the thickness direction of the end cap, and the maximum thickness of the end cap is B,1/4 ≦ C/B ≦ 3/5.

12. The end cap assembly of claim 10,

the fixing piece comprises a connecting end arranged in the concave part, and the connecting end is connected to at least one of the bottom wall and the side wall;

the end cover comprises a first surface and a second surface which are opposite to each other along the thickness direction of the end cover, wherein the first surface is a surface of the end cover close to the fixing piece, the second surface is a surface of the end cover departing from the fixing piece, and in the direction of pointing to the first surface along the second surface, the surface of the connecting end departing from the bottom wall does not exceed the first surface.

13. An end cap assembly according to any one of claims 1 to 12, wherein the thickness of the fixing member in the thickness direction of the end cap is D, the maximum thickness of the end cap is B, and 1/3 ≤ D/B ≤ 1/2.

14. An end cap assembly according to any one of claims 1 to 12, wherein the connecting portion sealingly connects the fixing member and the projection.

15. A battery cell comprising an end cap assembly according to any one of claims 1 to 14.

16. A battery comprising the cell of claim 15.

17. An electrical device comprising a battery as claimed in claim 16 for providing electrical energy.

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