WO2023246148A1

WO2023246148A1 - Battery cell, battery, and electrical device

Info

Publication number: WO2023246148A1
Application number: PCT/CN2023/078021
Authority: WO
Inventors: 雷育永; 郭志君
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-06-22
Filing date: 2023-02-24
Publication date: 2023-12-28
Also published as: CN218414808U; CN118020201A

Abstract

The present application relates to a battery cell, a battery, and an electrical device. The battery cell comprises a housing, an end cover, and an electrode assembly. The housing is provided with an opening and an end face surrounding the opening; the electrode assembly is accommodated in the housing; the end cover is used for covering the opening; the end cover comprises a main body part and at least one extension part surrounding the main body part; the extension part is welded with the end face; the main body part is provided with an assembly part located in the housing; the assembly part protrudes relative to the extension part in the thickness direction of the end cover. According to the battery cell in the present application, the extension part is welded with the housing, so that the connection strength of the end cover and the housing can be improved, thereby improving the structural stability of the battery cell. The assembly part protrudes into the housing, and the assembly part can reduce the risk that welding metal falls into an accommodation cavity, thereby having a good protection effect on the electrode assembly.

Description

Battery cells, batteries and electrical devices

Cross-references to related applications

This application claims priority over the invention patent application 202221571741.1 titled "Battery Cells, Batteries and Electrical Devices" submitted on June 22, 2022.

Technical field

The present application relates to the field of battery technology, and more specifically, to battery cells, batteries and electrical devices.

Background technique

Batteries are widely used in various electrical devices, such as mobile phones, laptops, battery cars, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, etc. Batteries typically include battery cells.

Battery cells usually include a casing and an end cover. The connection strength between the casing and the end cover is not strong enough, which can easily cause the end cover to loosen, thus affecting the structural stability of the battery cell.

Contents of the invention

This application provides a battery cell, battery and electrical device, aiming to improve the problem that the connection strength between the end cover and the casing of the battery cell is low and the end cover is prone to loosening, and can improve the structural stability of the battery cell. .

In a first aspect, this application proposes a battery cell. The battery cell includes a case, an end cover and an electrode assembly, wherein the case has an opening and an end surface surrounding the periphery of the opening; the electrode assembly is accommodated in the case; and the end cover Used to cover the opening, wherein the end cover includes a main body and at least one extension surrounding the outer circumference of the main body. The extension and the end face are welded and connected. The main body has an assembly part located in the housing, and the assembly part is along the thickness direction of the end cover. Projecting relative to the extension.

Therefore, in the battery cell of the embodiment of the present application, the extension part of the end cover and the case are welded, which can improve the connection strength between the end cover and the case, thereby improving the structural stability of the battery cell. In addition, the assembly part is located in the casing, and the assembly part has a certain shielding effect, which can reduce the risk of welding metal falling to the electrode assembly, thereby providing good protection for the electrode assembly and improving the safety performance of the battery cells; Moreover, the assembly part can increase the thickness of the end cover and improve the overall strength of the end cover.

In any embodiment, the housing includes at least one side wall disposed around the electrode assembly, and the side wall includes a first surface facing the electrode assembly; the assembly portion includes a peripheral side surface opposite to the first surface, and the peripheral side surface is planar with the first surface. row, along the thickness direction of the side wall, the maximum distance between the peripheral side surface and the first surface is S0, S0≤1mm.

Therefore, the maximum distance between the peripheral side surface and the first surface in the embodiment of the present application is less than or equal to 1 mm, the gap between the peripheral side surface and the first surface is small or even non-existent, and the welding metal produced during the welding process cannot easily pass through the peripheral side surface. The gap between the side and the first side falls into the interior of the housing, thereby reducing the risk of weld metal falling onto the electrode assembly.

In any embodiment, in the thickness direction of the end cap and in the direction approaching the electrode assembly, the peripheral side surface sequentially includes a first sub-surface and a second sub-surface, and the first sub-surface is in contact with the first sub-surface. The surface is welded and connected; there is a gap between the second sub-surface and the first surface, and the maximum size of the gap is S0 along the thickness direction of the side wall, S0≤1mm.

Therefore, in the embodiment of the present application, on the basis of the welding of the extension part and the casing, the first sub-surface of the assembly part is welded to the first surface, which increases the connection strength between the end cover and the casing, and strengthens the connection between the end cover and the casing. The firmness of the connection between them improves the structural stability of the battery cells. In addition, although there is a gap between the second sub-surface and the first surface, when the maximum distance of the gap is relatively small, the risk of welding metal falling onto the electrode assembly can be effectively reduced, thereby further improving the safety performance of the battery cell.

In any embodiment, the assembly part includes a bottom surface facing the electrode assembly and a transition surface, the transition surface connects the peripheral side surface and the bottom surface, and the transition surface is inclined relative to the peripheral side surface.

Therefore, the embodiment of the present application connects the bottom surface and the peripheral side surface through the transition surface, which can play a good guiding role for the end cover when the end cover is assembled into the shell and reduce the difficulty of assembly.

In any embodiment, the transition surface is a chamfered surface or a curved surface. The form of chamfered surface or curved surface can further improve the guiding effect and further reduce the difficulty of assembly.

In any embodiment, the dimension of the extension part along the thickness direction of the side wall is D0; the thickness of the side wall is T0; the maximum distance between the peripheral side surface of the assembly part and the first surface is S0, which is the sum of D0, T0 and S0. The space satisfies: |D0-T0-S0|≤0.8mm.

Therefore, the assembly relationship between the extension part, the side wall, the peripheral side surface and the side wall in the embodiment of the present application satisfies the relational expression |D0-T0-S0|≤0.8, which enables good assembly between the end cover and the housing. , and can reduce the risk of welding metal falling into the housing.

In any embodiment, the main body portion and the extension portion are of one-piece construction.

Therefore, the main body part and the extension part of the embodiment of the present application are an integrated structure, which can simplify the assembly steps of the end cover, improve the production efficiency of the battery cells, and the integrated structure has better structural strength and stability.

In any embodiment, the thickness of the extension is H1, 0.2mm≤H1≤3mm.

Therefore, when the thickness of the extension part in the embodiment of the present application meets the above numerical range, it can reduce the risk of the welding area extending above the end cap when the extension part is too thin. At the same time, having a certain thickness of the extension part can reduce the difficulty of the welding operation.

In any embodiment, the thickness of the assembly part is H0, 0.2mm≤H0≤3mm.

Therefore, the thickness of the assembly part of the embodiment of the present application is greater than or equal to 0.2 mm and less than or equal to 3 mm. The thickness of the assembly part is moderate. On the one hand, the assembly part has a relatively obvious thickness to facilitate assembly, and on the other hand, it avoids excessive thickness. It is large and occupies the accommodation cavity, thereby occupying the installation space of the electrode assembly, increasing the occupied space of the electrode assembly, and increasing the energy density of the battery cell.

In any embodiment, the projected profile of the electrode assembly on a plane perpendicular to the thickness direction of the end cap, within the projected contour of the assembly on the plane.

Therefore, the size of the electrode assembly in the thickness direction of the side wall of the embodiment of the present application is smaller than the size of the assembly part in this direction. The assembly part can better shield the electrode assembly to reduce the risk of welding metal falling into the accommodation cavity and damaging the electrode. Component Risks.

In a second aspect, the present application provides a battery, which includes the battery cell according to any embodiment of the first aspect of the present application.

In a third aspect, the present application provides an electrical device, which includes the battery according to the embodiment of the second aspect of the present application. Batteries are used to provide electrical energy.

Description of the drawings

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

Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application;

Figure 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application;

Figure 3 is a schematic structural diagram of a battery module provided by some embodiments of the present application;

Figure 4 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application;

Figure 5 is a schematic structural diagram of a battery cell provided by some embodiments of the present application;

Figure 6 is a schematic cross-sectional view of the battery cell shown in Figure 5;

Figure 7 is a partial enlarged schematic diagram of the battery cell shown in Figure 6 at position A;

Figure 8 is a partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B;

Figure 9 is another partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B;

Figure 10 is another partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B;

Figure 11 is another partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B;

Figure 12 is another partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B;

FIG. 13 is another partially enlarged schematic diagram of the battery cell shown in FIG. 7 at position B.

The drawings are not necessarily drawn to actual scale.

Explanation of reference symbols:
Battery cell; 1a, shell assembly; 1b, electrode assembly; 1c, electrode terminal; 1d, end cover assembly;
10. End cover; 20. Shell;
110. Main part; 111. Extension part;
12. Assembly part; 121. Side surface; 122. Bottom surface; 123. Transition surface;
22. Side wall; 22a, first surface; 22b, second surface; 22c, end surface;
23. Accommodation cavity; 24. Opening;
2. Battery module;
3. Battery; 3a. Box; 31. First box part; 32. Second box part; 33. Box space;
4. Vehicle; 41. Controller; 42. Motor.

Detailed ways

In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are Apply for some of the embodiments, not all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the technical field of this application; the terms used in the specification of this application are only for describing specific implementations. The purpose of the examples is not intended to limit the application; the terms "including" and "having" and any variations thereof in the description and claims of the application and the above description of the drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or priority relationship.

Reference in this application to "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of this 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 this application, it should be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection", "connection" and "attachment" should be understood in a broad sense. For example, it can be a fixed connection, It can also be detachably connected or integrally connected; it can be directly connected or indirectly connected through an intermediate medium; it can be internal communication between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

The term "and/or" in this application is just an association relationship describing related objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, alone There are three situations B. In addition, the character "/" in this application generally indicates that the related objects are an "or" relationship.

In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of simplicity, detailed descriptions of the same components in different embodiments are omitted. 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 and width of the integrated device, are only illustrative illustrations and should not constitute any limitation to the present application. .

"Plural" appearing in this application means two or more (including two).

In this application, the battery cells may include lithium ion secondary batteries, lithium ion primary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries or magnesium ion batteries, etc., which are not limited in the embodiments of this application. The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this. Battery cells are generally divided into three types according to packaging methods: cylindrical battery cells, rectangular battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.

The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly includes a positive electrode piece, a negative electrode piece and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode collector The fluid includes a positive electrode current collecting part and a positive electrode convex part protruding from the positive electrode current collecting part. The positive electrode current collecting part is coated with a positive electrode active material layer. At least part of the positive electrode convex part is not coated with a positive electrode active material layer. The positive electrode convex part serves as a positive electrode. Very ear. Taking lithium-ion batteries as an example, the material of the cathode current collector can be aluminum, and the cathode active material layer includes cathode active materials. The cathode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode current collecting part and a negative electrode convex part protruding from the negative electrode current collecting part, and the negative electrode current collecting part The negative electrode active material layer is coated on the negative electrode active material layer, and at least part of the negative electrode protruding part is not coated with the negative electrode active material layer, and the negative electrode protruding part serves as the negative electrode tab. The negative electrode current collector may be made of copper, and the negative electrode active material layer may include a negative electrode active material. The negative electrode active material may be carbon or silicon. In order to ensure that large currents can pass through without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the isolator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc. In addition, the electrode assembly may have a rolled structure or a laminated structure, and the embodiments of the present application are not limited thereto.

The battery cell may further include a housing assembly, which includes a housing and an end cover assembly. The housing has a receiving cavity, and the receiving cavity may provide a receiving space for the electrode assembly and the electrolyte. The end caps of the housing and end cap assembly are connected to each other.

The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application may include a battery module or a battery pack.

The development and progress of battery technology is related to many design factors, such as the energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters of the battery cells. In addition, the structural stability of the battery cells also needs to be considered.

The inventor found that the connection strength between the casing and the end cover of the battery cell is directly related to the structural stability and sealing of the battery cell. The low connection strength and connection reliability between the end cover and the casing can easily cause the battery to fail. The cell seal fails, resulting in reduced performance and safety of the battery cells.

After in-depth research, the inventor found that the reason why the connection strength and connection reliability between the end cover and the casing is not high is that the end cover and the casing are usually connected and sealed by laser welding. When the opening of the end cover or the casing is manufactured, When there is an error, a gap will appear between the two. During welding, the laser and metal welding slag will come into contact with the internal components of the battery cell, and even the end cap and the casing may have virtual welding.

In view of this, the inventor proposed a battery cell. The battery cell includes a casing and an end cover. The casing includes an opening and an end surface arranged around the opening. The end cover includes a main body and an extension. The extension surrounds the main body. Set, the extension part is welded to the shell, and the assembly part of the main body protrudes into the inside of the shell. Welding the extension part to the case can improve the connection strength and connection reliability between the end cover and the case, thereby improving the structural stability and safety performance of the battery cell. While providing positioning for the end cap, the assembly part also has a certain blocking effect on the opening, which can prevent laser or welding metal from falling onto the electrode assembly to a certain extent, and reduce the risk of short circuit caused by the isolator of the electrode assembly being melted through.

The technical solutions described in the embodiments of this application are applicable to batteries containing battery cells and electrical devices using batteries.

Electrical devices can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric Toys and power tools and more. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc.; spacecraft include aircraft, rockets, space shuttles, spaceships, etc.; electric toys include fixed Type or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more. The embodiments of this application impose no special restrictions on the above-mentioned electrical devices.

For convenience of explanation, the following embodiments take the electrical device as a vehicle as an example.

Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

Referring to Figure 1, a battery 3 is provided inside the vehicle 4. The battery 3 can be provided at the bottom, head or tail of the vehicle 4. The battery 3 may be used to power the vehicle 4 , for example, the battery 3 may be used as an operating power source for the vehicle 4 .

The vehicle 4 may also include a controller 41 and a motor 42. The controller 41 is used to control the battery 3 to provide power to the motor 42, for example, for the starting, navigation and working power requirements of the vehicle 4 during driving.

In some embodiments, the battery 3 can not only be used as an operating power source for the vehicle 4 , but also can be used as a driving power source for the vehicle 4 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 4 .

Figure 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application.

Referring to Figure 2, the battery 3 includes a case 3a and a battery cell (not shown in Figure 2), and the battery module 2 is accommodated in the case.

The box 3a is used to accommodate battery cells, and the box 3a can have various structures. In some embodiments, the box body 3a may include a first box body part 31 and a second box body part 32, the first box body part 31 and the second box body part 32 cover each other, the first box body part 31 and the second box body part 32 The two box parts 32 jointly define a box space 33 for accommodating battery cells. The second box part 32 may be a hollow structure with one end open, and the first box part 31 may be a plate-like structure. The first box part 31 covers the open side of the second box part 32 to form a box space. 33 of the box 3a; the first box part 31 and the second box part 32 can also be a hollow structure with one side open, and the open side of the first box part 31 is covered with the opening of the second box part 32 side to form a box 3a having a box space 33. Of course, the first box part 31 and the second box part 32 can be in various shapes, such as cylinder, rectangular parallelepiped, etc.

In order to improve the sealing performance after the first box part 31 and the second box part 32 are connected, a sealing member may also be provided between the first box part 31 and the second box part 32, such as sealant, sealing ring, etc. .

Assuming that the first box part 31 is covered on the top of the second box part 32, the first box part 31 can also be called an upper box cover, and the second box part 32 can also be called a lower box.

In the battery 3, there may be one battery cell or a plurality of battery cells. If there are multiple battery cells, the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells are connected in series and in parallel. Multiple battery cells can be directly connected in series, parallel, or mixed together, and then the whole composed of multiple battery cells can be accommodated in the box; multiple battery cells can also be connected in series, parallel, or mixed to form a battery. Module 2. A plurality of battery modules 2 are connected in series, parallel or mixed to form a whole, and are accommodated in the box 3a.

Figure 3 is a schematic structural diagram of a battery module provided by some embodiments of the present application.

Please refer to Figure 3. In some embodiments, there are multiple battery cells 1, and the multiple battery cells 1 are connected in series or They are connected in parallel or mixed to form the battery module 2. A plurality of battery modules 2 are connected in series, parallel or mixed to form a whole, and are accommodated in the box.

The plurality of battery cells 1 in the battery module 2 can be electrically connected through bus components to achieve parallel, series or mixed connection of the multiple battery cells 1 in the battery module 2 .

Figure 4 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application.

Referring to Figure 4, the battery cell 1 provided by the embodiment of the present application includes a housing assembly 1a.

In some embodiments, the battery cell 1 further includes an electrode assembly 1 b, and the housing assembly 1 a can be used to accommodate the electrode assembly 1 b.

In some embodiments, the housing assembly 1a may also be used to contain an electrolyte, such as an electrolyte.

In some embodiments, the housing assembly 1a may include a housing 20 and an end cover assembly 1d. The housing 20 is a hollow structure with one side open. The end cover assembly 1d covers the opening of the housing 20 and forms a sealed connection. A housing cavity for housing the electrode assembly 1b and the electrolyte is formed.

The housing 20 can be in various shapes, such as cylinder, cuboid, etc. The shape of the housing 20 can be determined according to the specific shape of the electrode assembly 1b. For example, if the electrode assembly 1b has a cylindrical structure, the housing 20 can be a cylindrical housing; if the electrode assembly 1b has a rectangular parallelepiped structure, the housing 20 can be a rectangular parallelepiped housing. In FIG. 4 , as an example, the housing 20 has a rectangular parallelepiped structure.

In some embodiments, the end cap assembly 1d includes an end cap 10, and the end cap 10 is used to cover the opening of the housing 20. The end cap 10 can be of various structures. For example, the end cap 10 can be a plate-like structure, a hollow structure with one end open, etc. For example, in FIG. 4 , the housing 20 has a rectangular parallelepiped structure, the end cover 10 has a plate-like structure, and the end cover 10 covers the opening at the top of the housing 20 .

The end cap 10 can be made of insulating material (such as plastic) or conductive material (such as metal). When the end cover 10 is made of metal material, the end cover 10 is also connected with an insulating member, and the insulating member is located on the side of the end cover 10 facing the electrode assembly to insulate and separate the end cover 10 from the electrode assembly 1b.

In some embodiments, the end cap assembly 1d may also include an electrode terminal 1c mounted on the end cap 10. There are two electrode terminals 1c, and the two electrode terminals 1c are respectively defined as a positive electrode terminal and a negative electrode terminal. Both the positive electrode terminal and the negative electrode terminal are used to electrically connect with the electrode assembly 1b to output the electric energy generated by the electrode assembly 1b.

In other embodiments, the housing assembly 1a can also be of other structures. For example, the housing assembly 1a includes a housing 20 and two end cover assemblies 1d. The housing 20 is a hollow structure with openings on opposite sides, and one end cover assembly 1d. The corresponding cover is closed at an opening of the housing 20 and forms a sealed connection to form a receiving cavity for receiving the electrode assembly 1b and the electrolyte. In this structure, one end cover assembly 1d may be provided with two electrode terminals 1c, while the other end cover assembly 1d may not be provided with the electrode terminal 1c, or the two end cover assemblies 1d may each be provided with one electrode terminal 1c.

In the battery cell 7, there may be one electrode assembly 1b accommodated in the case assembly 1a, or a plurality of electrode assemblies 1b. For example, in Figure 4, there are four electrode assemblies 1b.

Figure 5 is a schematic structural diagram of a battery cell provided by some embodiments of the present application; Figure 6 is a schematic cross-sectional view of the battery cell shown in Figure 5; Figure 7 is a partial enlargement of the battery cell shown in Figure 6 at position A. Schematic diagram; Figure 8 is a partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B.

Referring to Figures 4 to 8, the battery cell 1 includes a case 20, an end cap 10 and an electrode assembly 1b, which , the housing 20 has an opening 24 and an end surface 22c surrounding the periphery of the opening 24. The electrode assembly 1b is accommodated in the housing 20. The end cover 10 is used to cover the opening 24. The end cover 10 includes a main body 110 and a main body 110 surrounding the main body. At least one extension portion 111 on the outer periphery of 110 is welded to the end surface 22c. The main body portion 110 has an assembly portion 12 located in the housing 20. The assembly portion 12 protrudes relative to the extension portion 111 along the thickness direction X of the end cover 10. .

The housing 20 has a receiving cavity 23, which includes an opening. The receiving cavity 23 can have the same shape as the electrode assembly. For example, the electrode assembly has a rectangular parallelepiped structure, and the receiving cavity 23 has a rectangular parallelepiped cavity. The electrode assembly has the same shape as the receiving cavity 23. At the same time, the electrode assembly has better assembly performance, and the space utilization rate of the accommodation cavity 23 is high. Of course, the shape of the electrode assembly can also be different from that of the accommodation cavity 23; it can be comprehensively considered based on the shape of the electrode assembly, the manufacturing process of the housing 20, the production cost, etc., and this application does not limit this.

The end cap 10 is used to cover the opening. The end cap 10 and the shell 20 can be made of the same material or different materials. The material can be alloy steel, carbon steel, aluminum alloy, non-ferrous alloy, etc., for example , the end cover 10 and the shell 20 are both made of aluminum alloy, which has the advantages of high strength, light weight, and easy molding.

The end cap 10 includes a main body part 110 and an extension part 111 that are connected to each other. The extension part 111 and the main body part 110 may be integrally formed, or they may be separately manufactured and then connected as one body. Optionally, the extension part 111 and the main part 110 are made of the same material. Using the same material can simplify the manufacturing process, reduce manufacturing costs, and improve production efficiency; and when made of the same material, if they are formed separately Connecting later can reduce the difficulty of connecting the two. For example, when the two are welded, it is less difficult to weld profiles of the same material, and the welded parts also have higher structural strength. Of course, the extension part 111 and the main part 110 can also be made of different materials.

The extension part 111 is provided around the main body part 110. When the housing 20 has a cylindrical structure, one extension part 111 may be provided, and one extension part 111 is provided around the outer periphery of the main body part 110; when the housing 20 has a rectangular parallelepiped structure, the extension part 111 There may be four extension parts 111 connected in sequence and arranged around the outer periphery of the main body part 110 .

The assembly part 12 protrudes relative to the extension part 111. The assembly part 12 can increase the thickness of the main body part 110, thereby increasing the overall thickness of the end cover 10, thus improving the strength of the end cover 10 itself and improving the resistance of the end cover 10 to impact force. Ability. Moreover, the assembly part 12 protrudes into the accommodation cavity 23. The assembly part 12 has a certain blocking effect on the opening of the accommodation cavity 23, which can reduce to a certain extent the laser irradiation into the accommodation cavity 23 or the welding metal (welding slag) falling into the accommodation cavity 23. The risk of damaging the electrode assembly in the accommodation cavity 23 ensures the performance of the electrode assembly. The assembly part 12 can match the shape of the accommodation cavity 23. For example, the accommodation cavity 23 is a cylinder, and the assembly part 12 can also be a cylinder. The advantage of matching the shape of the assembly part 12 with the accommodation cavity 23 is that the assembly part 12 is assembled into the accommodation cavity. When the cavity is 23, it has better assembly performance. Of course, the assembly part 12 may also have different shapes from the accommodation cavity 23 .

The end cover 10 according to the embodiment of the present application includes a main body part 110 and an extension part 111. The extension part 111 is welded to the case 20, which can improve the connection strength between the end cover 10 and the case 20, so that the battery cell 1 The structural stability is improved, so that when the battery cell 1 is used in a battery, the overall structural stability of the battery can be improved. Moreover, the mounting portion 12 protrudes into the housing 20. On the one hand, the mounting portion 12 can increase the overall thickness of the end cover 10, thereby improving the strength of the end cover 10; on the other hand, the mounting portion 12 has a connection to the opening 24 of the housing 20. A certain shielding effect can reduce the risk of laser or welding metal reaching the inside of the battery cell 1, thereby protecting the electrode assembly inside the battery cell 1, and the assembly part 12 protrudes into the housing 20, which can be The end cap 10 provides positioning relative to the housing 20 to facilitate subsequent connection.

The housing 20 in the embodiment of the present application has various structural forms, such as a rectangular parallelepiped structure or a cylindrical structure. When the housing 20 is a rectangular parallelepiped housing, the housing 20 may include four side walls 22 , and the four side walls 22 are connected in sequence and enclose to form the accommodation cavity 23 . When the housing 20 is a cylindrical housing, the housing 20 may include a side wall 22 that encloses a receiving cavity 23; the following is the assembly relationship between the structural form of the housing 20 and the end cover 20. Be explained.

Referring to FIGS. 7 and 8 , the housing 20 includes at least one side wall 22 surrounding the electrode assembly. The side wall 22 includes a first surface 22 a facing the electrode assembly, and the mounting portion 12 includes a peripheral side surface opposite to the first surface 22 a. 121. The peripheral side surface 121 is parallel to the first surface 22a. Along the thickness direction Y of the side wall 22, the maximum distance between the peripheral side surface 121 and the first surface 22a is S0, S0≤1mm. In this application, the peripheral side surface 121 and the first surface 22a may be parallel or approximately parallel, that is, there is a tendency for the peripheral side surface 121 and the first surface 22a to intersect. For example, the angle between the peripheral side surface 121 and the first surface 22a is 3. Within °; of course, they can also be completely parallel, that is, the peripheral side surface 121 and the first surface 22a will not intersect.

The Y direction shown in FIGS. 7 and 8 represents the thickness direction of the side wall 22 , which direction is perpendicular to the thickness direction X of the end cap 10 . S0 represents the maximum distance between the peripheral side surface 121 and the first surface 22a. S0 can be 0 or a non-zero value; specifically, S0=(W0-L0)/2, where L0 is the Y axis of the assembly part 12 The size in the direction, W0 is the size of the accommodation cavity 23 in the Y direction, that is, W0 is the distance between the two first surfaces 22a facing each other along the Y direction. When S0 in the embodiment of the present application satisfies the above numerical range, the gap between the peripheral side surface 121 and the first surface 22a is small or even non-existent, which can improve the ability of the assembly part 12 to prevent the welding metal from falling to the battery cells to a certain extent. The risk of damage to the electrode assembly inside the body is eliminated, thereby ensuring the performance of the electrode assembly and improving the positioning accuracy of the end cap 10 relative to the housing 20 .

The connection relationship between the peripheral side surface 121 and the first surface 22a in the embodiment of the present application can be flexibly selected according to the specific process; for example, the peripheral side surface 121 may not be welded to the first surface 22a, or may be welded to the first surface 22a. It is explained in detail below.

In some embodiments, the peripheral side 121 and the first side 22a are not welded.

Please continue to refer to Figures 7 and 8. In some examples, there is a gap between at least part of the peripheral side surface 121 and the first surface 22a; the existence of this gap is based on ensuring the connection strength of the end cover 10 and the housing 20. , allowing a certain deviation when the end cover 10 is assembled into the housing 20, which is beneficial to assembly.

Illustratively, there is a gap between a part of the peripheral side surface 121 and the first surface 22a. In other words, a part of the peripheral side surface 121 is in contact with the first surface 22a, and there is basically no gap; the other part has a gap between the first surface 22a and the first surface 22a. And the maximum distance between the portion with the gap and the first surface 22a is S0, and S0 is less than or equal to 1 mm. Taking the case 20 as a rectangular parallelepiped case as an example, the case 20 has four side walls 22 , and the four side walls 22 are arranged opposite each other. After the assembly part 12 is assembled into the case, the two side walls 22 facing each other are One of the side walls 22 is in contact with the first surface 22a, and there is a distance between the other side wall 22 and the first surface 22a, and the distance is less than or equal to 1 mm.

Of course, there may be a gap between the entire peripheral side surface 121 and the first surface 22a, and the maximum size of the gap is less than or equal to 1 mm. It can be understood that in this case, there is no contact between the peripheral side surface 121 and the first surface 22a, and the assembly portion 12 receives less assembly resistance when being assembled into the housing, so that the end cover 10 has better assembly. sex. M in Figure 8 shows the welding area, that is, the welding mark, between the end cover 10 and the housing 20.

Figure 9 is another partially enlarged schematic diagram of the battery cell shown in Figure 7 at position B.

Please refer to FIG. 9 . In other examples, after the assembly part 12 is assembled into the accommodation cavity 23 , the peripheral side surface 121 and the first surface 22 a can fit together. In this case, the peripheral side surface 121 and the first surface 22 a can fit together. There is basically no gap, and S0=0 at this time. In this case, the assembly part 12 can better block the opening of the accommodating cavity 23. When the extension part 111 and the housing 20 are welded, the main part 110 can have a better blocking effect on the welding metal, reducing the loss of welding metal. There is a risk of damaging the electrode assembly by falling inside the battery cell 1, thus providing good protection for the electrode assembly.

FIG. 10 is another partially enlarged schematic view of the battery cell shown in FIG. 7 at position B; FIG. 11 is another partially enlarged schematic view of the battery cell shown in FIG. 7 at position B.

Referring to Figures 10 and 11, in some embodiments, the peripheral side 121 and the first side 22a are welded. When the extension part 111 is welded to the housing 20, the peripheral side surface 121 and the first surface 22a are welded, which increases the connection area of the connection part between the end cover 10 and the housing 20, and can improve the connection between the two. The connection strength further improves the structural stability of the battery cells.

Specifically, in the thickness direction There is a gap between the second sub-surface 1212 and the first surface 22a. Along the thickness direction Y of the side wall 22, the maximum size of the gap is S0, S0≤1 mm. In this application, along the direction approaching the electrode assembly, it can be understood as the direction from the end cover 10 to the electrode assembly; and the first sub-surface 1211 and the second sub-surface 1212 are connected in sequence.

The first sub-surface 1211 and the first surface 22a are welded and connected, which can improve the connection strength between the end cover 10 and the housing 20; there is a gap between the second sub-surface 1212 and the first surface 22a, and the size of the gap is small. It can effectively reduce the risk of welding slag falling during the welding process of the first sub-surface 1211 and the first surface 22a, has a certain blocking effect, and can effectively protect the electrode assembly.

Further, the dimension of the first sub-surface 1211 along the thickness direction X of the end cap 10 is L1; the dimension of the second sub-surface 1212 along the thickness direction of the end cap 10 is L2, where L2>0. As L1 increases, the connection strength between the end cover 10 and the housing 20 increases; as L2 increases, the blocking ability of the welding slag between the second sub-surface 1212 and the housing 20 increases. On the basis of ensuring the connection strength between the end cover 10 and the casing 20, this application can effectively reduce the risk of welding slag falling into the electrode assembly, thereby improving the safety performance of the battery cells. FIG. 10 shows a schematic diagram of the connection between the end cover 10 and the housing 20 (the welding mark is not shown). M shown in FIG. 11 is the welding area, that is, the welding mark, of the end cover 10 and the housing 20 .

FIG. 12 is another partially enlarged schematic view of the battery cell shown in FIG. 7 at position B; FIG. 13 is another partially enlarged schematic view of the battery cell shown in FIG. 7 at position B.

Referring to Figures 12 and 13, in some embodiments, the dimension D0 of the extension portion 111 along the Y direction, the thickness T0 of the side wall 22, and the maximum distance S0 between the peripheral side surface 121 of the mounting portion 12 and the first surface 22a are The space satisfies: |D0-T0-S0|≤0.8mm.

|D0-T0-S0|≤0.8, that is, -0.8≤D0-T0-S0≤0.8, which can be understood as the step difference between the surface of the extension part 111 away from the main body part 110 and the outer surface of the side wall 22 is less than or equal to 0.8mm, the size of the extension 111 along the Y direction, the thickness of the side wall 22, and the maximum distance between the peripheral side 121 and the first surface 22a have a matching relationship of |D0-T0-S0|≤0.8mm, which can make the end On the premise that the cover 10 and the housing 20 have good assembly, the risk of welding metal entering the accommodation cavity 23 can also be reduced during later welding, thereby affecting the electrodes inside the housing 20. The components are better protected; such an arrangement can also make the outer surface of the battery cell have better flatness, which is beneficial to the packaging, transportation, and later installation and use of the battery cell.

The side wall 22 of the embodiment of the present application includes a second surface 22b opposite to the first surface 22a along the Y direction.

In some examples, the second surface 22b extends beyond the surface of the extension 111 in the direction from the first surface 22a to the second surface 22b. It can be understood that the extension portion 111 is recessed relative to the second surface 22b, and the end cover 10 is recessed relative to the housing 20 in the Y direction. This arrangement can reduce the assembly space of the battery cells.

In other examples, in the direction from the first surface 22a to the second surface 22b, the second surface 22b is flush with the surface of the extension 111. This arrangement can also reduce the overall assembly space of the battery cell, and also can It can improve the surface flatness of battery cells.

In some other examples, in the direction from the first surface 22a to the second surface 22b, the surface of the extension part 111 exceeds the second surface 22b. At this time, the extension part 111 can protect the casing 20. When the battery cell is subjected to external impact, the extension part 111 of the end cover 10 can protect the casing 20, thereby reducing the impact on the casing 20. Risk of damage from external shocks.

Please continue to refer to Figures 12 and 13. In some embodiments, the assembly part 12 also includes a bottom surface 122 and a transition surface 123 facing the electrode assembly; the transition surface 123 connects the peripheral side surface 121 and the bottom surface 122, and the transition surface 123 is compared with the peripheral surface 122. Side 121 inclined setting.

The transition surface 123 can be a surface of various shapes, such as a chamfered surface, a flat surface, a curved surface, etc. The transition surface 123 can guide the assembly part 12 when the end cover 10 is assembled into the housing 20 and reduce the assembly resistance. .

Further, at least part of the transition surface 123 is a curved surface. The curved surface has better guiding properties and can reduce the assembly resistance of the assembly part 12 to a greater extent. Moreover, the structure of the curved surface is relatively simple and the molding methods are diverse, which simplifies the preparation difficulty. Figure 10 shows that at least part 123 of the transition surface is curved.

In some embodiments, the main part 110 and the extension part 111 are an integral structure.

The main part 110 and the extension part 111 are an integrated structure, and they can be formed in one piece. The assembly with the shell 20 is better. There is no need to assemble the main part 110 and the extension part 111 in multiple steps, and then assemble the extension part 111 and the shell. The body 20 is welded to improve the assembly efficiency of the battery cells. Moreover, the one-piece structure has better connection stability and structural strength.

Please continue to refer to Figure 13. In some embodiments, the thickness of the extension portion 111 is H1, 0.2mm≤H1≤3mm. Setting the thickness of the extension part 111 within the above range can alleviate problems such as the welding area extending above the end cap 10 when the extension part 111 is too thin, causing damage to the surface of the end cap 10 and making the surface of the end cap uneven. . At the same time, the extension part 111 has a certain thickness, which can ensure the strength of the end cap.

In some embodiments, the thickness of the assembly portion 12 is H0, 0.2mm≤H0≤3mm. On the one hand, the thickness of the assembly part 12 is greater than or equal to 0.2mm. The assembly part 12 can significantly improve the overall strength of the end cover, and can reduce to a certain extent the possibility that the assembly part 12 is not assembled in place and is difficult to install due to the assembly part 12 being too thin. The problem found; on the other hand, the thickness of the assembly part 12 is less than or equal to 3 mm, which can prevent the assembly part 12 from excessively occupying the space of the accommodation cavity 23, thereby occupying the accommodation space of the electrode assembly, and causing interference with the electrode assembly, and thus can Increase the occupied space of the electrode assembly, thereby increasing the energy density of the battery cell.

In some embodiments, the projection of the electrode assembly on a plane perpendicular to the thickness direction X of the end cap 10 The contour is located within the projected contour of the assembly part 12 on this plane.

Therefore, the mounting portion 12 can cover the electrode assembly in the thickness direction of the end cover 10 , and the mounting portion 12 can better shield the electrode assembly, thereby reducing the risk of the electrode assembly being burned by falling welding metal.

As a specific embodiment of the present application, please refer to Figures 4 to 8. The battery cell 1 of the embodiment of the present application includes a case 20, an end cap 10 and an electrode assembly 1b. The case 20 includes an opening 24 and a periphery surrounding the opening 24. The end face 22c of the end cap 10 is used to cover the opening 24. The end cap 10 includes a main body part 110 and at least one extension part 111 surrounding the outer circumference of the main body part 110. The main body part 110 has an assembly part 12 located in the housing 20. The assembly part 12 is relative to the end cap 10 along the thickness direction X. The extension part 111 protrudes, and the peripheral side surface 121 of the assembly part 12 is parallel to the first surface 22a of the side wall 22 of the housing 20, and the maximum distance between them is S0, S0≤1 mm.

In this embodiment, the extension part 111 is welded to the case 20, which can ensure the connection strength between the end cover 10 and the case 20, thereby improving the overall structural stability of the battery cell. The maximum distance between the peripheral side 121 of the assembly part 12 and the first surface 22a of the side wall 22 is S0, and S0 ≤ 1 mm. The gap between the two is small or even non-existent, which can block the welding metal to a certain extent. It falls into the accommodation cavity 23 to protect the electrode assembly and improve the overall strength of the end cover 10 .

Although the application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for parts thereof without departing from the scope of the application, in particular provided that no structural conflicts exist , the technical features mentioned in each embodiment can be combined in any way. The application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell including:

A housing having an opening and an end surface surrounding the periphery of the opening;

an electrode assembly housed in the housing; and

An end cap used to cover the opening;

Wherein, the end cover includes a main body part and at least one extension part surrounding the outer circumference of the main body part, the extension part is welded to the end face, the main body part has an assembly part located in the housing, and the The fitting portion protrudes relative to the extension portion along a thickness direction of the end cap.
The battery cell according to claim 1, wherein

The housing includes at least one side wall disposed around the electrode assembly, the side wall including a first side facing the electrode assembly;

The assembly part includes a peripheral side surface opposite to the first surface. The peripheral side surface is parallel to the first surface. Along the thickness direction of the side wall, there is a gap between the peripheral side surface and the first surface. The maximum spacing is S0, S0≤1mm.
The battery cell according to claim 2, wherein in the thickness direction of the end cover and in the direction approaching the electrode assembly, the peripheral side surfaces include:

The first sub-surface is welded and connected to the first surface;

There is a gap between the second sub-surface and the first surface. Along the thickness direction of the side wall, the maximum size of the gap is S0, S0≤1mm.
The battery cell according to claim 2 or 3, wherein the assembly part includes:

facing the bottom surface of the electrode assembly; and

A transition surface connects the peripheral side surface and the bottom surface, and the transition surface is inclined relative to the peripheral side surface.
The battery cell according to claim 4, wherein the transition surface is a chamfered surface or a curved surface.
The battery cell according to any one of claims 2 to 5, wherein,

The dimension of the extension portion along the thickness direction of the side wall is D0;

The thickness of the side wall is T0;

The maximum distance between the peripheral side surface of the assembly part and the first surface is S0,

The relationship between D0, T0 and S0 satisfies: |D0-T0-S0|≤0.8mm.
The battery cell according to any one of claims 1 to 6, wherein the main body part and the extension part are of an integrated structure.
The battery cell according to any one of claims 1 to 7, wherein

The thickness of the extension part is H1, 0.2mm≤H1≤3mm.
The battery cell according to any one of claims 1 to 8, wherein,

The thickness of the assembly part is H0, 0.2mm≤H0≤3mm.
The battery cell according to any one of claims 1 to 9, wherein,

The projected outline of the electrode assembly on a plane perpendicular to the thickness direction of the end cap is located within the projected outline of the assembly part on the plane.
A battery including the battery cell according to any one of claims 1 to 10.
An electrical device includes the battery according to claim 11, and the battery is used to provide electrical energy.