WO2024016487A1

WO2024016487A1 - Battery cell, battery, and electrical device

Info

Publication number: WO2024016487A1
Application number: PCT/CN2022/124572
Authority: WO
Inventors: 袁海峰; 黄奶兴; 许文竹
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-07-18
Filing date: 2022-10-11
Publication date: 2024-01-25
Also published as: CN217719895U

Abstract

The present application relates to a battery cell, a battery, and an electrical device. The battery cell comprises an electrode assembly and an end cap assembly; the electrode assembly comprises tab portions; the end cap assembly comprises electrode terminals and an end cap, and the end cap assembly is further provided with first through holes running through the end cap; each electrode terminal comprises a body portion and an extension portion; the body portion is fixedly mounted on the end cap and disposed in the corresponding first through hole; the extension portion is connected to the body portion and the corresponding tab portion, the extension portion is disposed around the body portion and extends relative to the body portion in a direction facing away from the axis of the first through hole, and the extension portion is disposed on the side of the end cap facing the electrode assembly. The battery cell of the present application comprises the extension portions, and the tab portions are connected to the extension portions, so that the contact area between the tab portions and the extension portions can be increased, the overcurrent capability of the tab portions and the electrode terminals is improved, and the charging and discharging performance of the battery cell is further improved.

Description

Battery cells, batteries and electrical devices

Cross-references to related applications

This application claims priority to Chinese patent application 202221836799.4 titled "Battery Cells, Batteries and Electric Devices" submitted on July 18, 2022. The entire content of this application is incorporated herein by reference.

Technical field

This application relates to the field of battery technology, and in particular to battery cells, batteries and electrical devices.

Background technique

Battery cells are widely used in electronic 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. The battery cells may include cadmium-nickel battery cells, nickel-hydrogen battery cells, lithium-ion battery cells, secondary alkaline zinc-manganese battery cells, etc.

In the development of battery technology, it is necessary to ensure the safety of battery cells and to improve the charge and discharge performance of battery cells as much as possible. If the charging and discharging performance of a battery cell is poor and cannot meet user requirements, the battery cell will eventually be eliminated from the market. Therefore, how to improve the charge and discharge performance of battery cells has become one of the technical problems that need to be solved urgently.

Contents of the invention

This application provides a battery cell, a battery and a power device, aiming to improve the charging and discharging performance of the battery cell.

In a first aspect, this application proposes a battery cell. The battery cell includes an electrode assembly and an end cover assembly. The electrode assembly includes a lug part. The end cover assembly includes an electrode terminal and an end cover. The end cover assembly is also provided with A first through hole penetrating through the end cover, wherein the electrode terminal includes a main body part and an extension part. The main part is fixedly installed on the end cover and is disposed in the first through hole; the extension part connects the main body part and the tab part, and the extension part surrounds The main body portion is disposed and extends relative to the main body portion in a direction away from the axis of the first through hole, and the extension portion is disposed on a side of the end cap facing the electrode assembly.

Therefore, the battery cell includes an extension part, and the tab part is connected to the extension part, which can increase the contact area between the tab part and the extension part, thereby improving the overcurrent capacity of the tab part and the electrode terminal, thereby improving the charging capacity of the battery cell. Discharge performance.

In some embodiments, the electrode assembly further includes an electrode body, the tab portion includes a first portion and a second portion connected to each other, and the projections of the first portion and the second portion along the axial direction of the first through hole at least partially overlap, and the One part is connected to the extension part, and the second part is connected to the electrode body.

Therefore, the lug part includes a first part and a second part, and the projections of the first part and the second part along the axial direction of the first through hole overlap, which can reduce the difficulty of connection between the lug part and the extension part.

In some embodiments, the first part includes a second through hole disposed opposite to the first through hole, the main part extends to the second through hole, and the extension part is connected to a side of the first part away from the end cap.

Therefore, the first part has a larger contact area with the extension part, which can improve the overcurrent capability of the tab part and the electrode terminal.

In some embodiments, along the axial direction of the first through hole, the projection of the extension portion is located within the projection of the first portion.

As a result, the contact area between the extension part and the first part is larger, and the overcurrent capability between the tab part and the electrode terminal is stronger.

In some embodiments, the first and second portions are of unitary construction.

As a result, the tab portion is integrally formed and has higher structural strength, thereby improving the structural stability of the battery cell.

In some embodiments, the battery cell includes a current collecting member, the current collecting member includes a third through hole disposed opposite to the first through hole, the main body portion extends to the third through hole, and the current collecting member is disposed on the end cover facing the electrode assembly. one side, and the current collecting member connects the extension part and the lug part.

Therefore, the battery cell includes a current collecting member, and the current collecting member can serve as a conductive medium between the tab portion and the electrode terminal, thereby reducing the difficulty of directly connecting the tab portion and the electrode terminal. Moreover, the current collecting member in the embodiment of the present application has a third through hole, and the main part extends to the third through hole, which increases the contact area between the current collecting member and the extension part and improves the flow capacity between them. .

In some embodiments, the lug portion includes a second through hole that is opposite to the first through hole, the main body portion extends to the second through hole, and a side of the current collecting member facing the end cover is connected to the lug portion, and the current collecting member The side of the component facing away from the end cap is connected to the extension.

Therefore, the pole lug part also includes a second through hole, and the main body part extends to the second through hole and the third through hole in sequence, further increasing the contact area between the current collecting member and the pole lug part, and improving the efficiency between the two. overcurrent capability.

In some embodiments, along the axial direction of the first through hole, the projection of the extension portion is located within the projection of the current collecting member.

As a result, the contact area between the extension part and the current collecting component is larger, thereby improving the flow capacity between the extension part and the current collecting component.

In some embodiments, along the axial direction of the first through hole, at least part of the projection of the tab portion is located within the projection of the current collecting member.

As a result, the contact area between the pole tab and the current collecting member is larger, thereby improving the current passing capacity between the pole tab and the current collecting member.

In some embodiments, a side of the current collection member facing away from the end cap is connected to both the tab portion and the extension portion.

Therefore, the tab part and the extension part are both connected to the same side of the current collecting member, which can reduce the space occupied by the three connections and reduce the occupation of the electrode body accommodation space of the electrode assembly.

In some embodiments, the battery cell further includes an insulating member, the extension includes a first surface, the first surface is a surface of the extension facing away from the end cover, and the insulating member at least covers the first surface.

Therefore, the insulator can protect the electrode assembly and improve the safety of the battery cells.

In some embodiments, the body portion includes a second surface flush with the first surface, and the insulating member also covers the second surface.

As a result, the insulating member increases the protection area of the electrode assembly, further improving the safety of the battery cells.

In some embodiments, the main body portion includes a connecting body and a protruding portion, the protruding portion protrudes relative to a surface of the end cap facing away from the electrode assembly, the connecting body is disposed in the first through hole and connects the protruding portion and the extending portion, Wherein, at least part of the outer peripheral surface of the protrusion has an external thread.

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 some embodiments, a plurality of battery cells are provided, each battery cell includes a main body, the main body includes a protruding portion, and at least part of the outer peripheral surface of the protruding portion has external threads; the battery further includes a device that connects two adjacent ones. A bus part of a battery cell, the bus part has an internal thread matching the external thread of the protruding part.

As a result, the battery cell is threadedly connected to the bus component. Compared with welding, the threaded connection can reduce the possibility of disconnection or short circuit between the bus component and the battery cell due to false welding, thereby reducing the probability of short circuit or disconnection in the battery. , which can improve the reliability and safety of the battery.

In a third aspect, this application provides an electrical device, which includes a battery as in any embodiment of the second aspect of this application; the battery is used to provide electrical energy.

Description of 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 a schematic structural diagram of a battery module provided by other embodiments of the present application;

Figure 5 is an exploded schematic diagram of the battery module shown in Figure 4;

Figure 6 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application;

Figure 7 is a partial cross-sectional schematic diagram of a battery cell provided by some embodiments of the present application;

Figure 8 is a partial enlarged view of the battery cell shown in Figure 7 at position A;

Figure 9 is a partial cross-sectional schematic diagram of a battery cell provided by other embodiments of the present application;

Figure 10 is a partial enlarged view of the battery cell shown in Figure 9 at position B;

Figure 11 is a partial cross-sectional schematic diagram of a battery cell provided by some embodiments of the present application.

Explanation of reference symbols:

1. Battery cell; 1a. Convergence part;

10. Electrode assembly; 11. Electrode body; 12. Pole lug; 13. Current collecting member; 14. Insulating piece;

121. The first part; 122. The second part; 121a. The second through hole; 131. The third through hole;

2a. Shell assembly; 20. End cover assembly; 21. Shell; 210. Accommodation cavity;

22. Electrode terminal; 221. Main body; 222. Extension part; 221a, protruding part; 221b, connection body;

23. End cover; 231. First through hole;

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, square battery cells and soft-pack battery cells, and the embodiments of the present application are not limited to this.

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. Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

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, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode current collecting part and a positive electrode convex part protruding from the positive electrode current collecting part, and the positive electrode current collecting part The positive electrode convex part is coated with the positive electrode active material layer, and at least part of the positive electrode convex part is not coated with the positive electrode active material layer, and the positive electrode convex part serves as the positive electrode tab. 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 also include a casing assembly, which includes a casing and an end cover assembly. The casing has an accommodating cavity inside, and the accommodating cavity is a sealed space provided by the casing for the electrode assembly and the electrolyte. The end cover assembly also includes an end cover and an electrode terminal connected to the end cover. The electrode terminal penetrates the end cover and is electrically connected to the positive and negative tabs of the electrode assembly in the accommodation cavity. The tabs are connected to the electrode terminals so that the battery cells Ability to charge and discharge with external devices.

The inventor found that among the many factors that restrict the performance improvement of a battery cell, the overcurrent capability of the battery cell is one of the most important factors affecting the performance of the battery cell. The tabs and electrode terminals serve as current carriers when charging and discharging the battery cells, which can directly affect the charging and discharging efficiency of the battery cells. Therefore, improving the overcurrent capability between the tabs and electrode terminals is of great significance to improving the charge and discharge performance of the battery cells.

In view of this, the inventor has improved the structure of the existing battery cell and proposed a battery cell. The battery cell includes an end cover assembly. The end cover assembly includes an end cover and an electrode terminal. The electrode terminal has a main body and a The extension part is connected to the main body, and the extension part is connected to the tab, which increases the contact area with the tab, improves the overcurrent capacity between the tab and the electrode terminal, thereby improving the charge and discharge of the battery cell. performance.

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

Power-consuming devices can be vehicles, cell phones, portable devices, laptops, ships, spacecraft, electric toys and power tools, etc. 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, 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 electrical equipment.

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.

As shown in FIG. 1 , a battery 3 is provided inside the vehicle 4 , and 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 of the present application, 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.

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

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 or parallel or mixed together, and then the whole composed of multiple battery cells can be accommodated in the box 3a; of course, multiple battery cells can also be connected in series or parallel first or A battery module 2 is formed by a mixed connection, and multiple 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.

As shown in Figure 3, in some embodiments, there are multiple battery cells 1, and the plurality of battery cells 1 are first 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.

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 . The bus part can be welded to the electrode terminal of the battery cell 1 to connect two adjacent battery cells 1 .

FIG. 4 is a schematic structural diagram of a battery module provided by other embodiments of the present application; FIG. 5 is an exploded schematic diagram of the battery module shown in FIG. 4 .

As shown in Figures 4 and 5, the battery module 2 includes a battery cell 1 and a bus part 1a. The bus part 1a is threadedly connected to the electrode terminal of the battery cell 1. The bus part 1a includes a nut, and the nut has a tightening effect.

The threaded connection between the bus part 1a and the electrode terminal of the battery cell 1 is more reliable than welding, and can reduce the possibility of open circuit or short circuit between the bus part 1a and the battery cell 1 due to false welding. property, thereby reducing the probability of short circuit or open circuit in the battery module 2, thereby improving the reliability and safety of the battery module 2. Moreover, the threaded connection operation is simpler and can improve production efficiency. In some embodiments, the electrode terminal of each battery cell 1 includes a main body portion, and the main body portion includes a protruding portion. When multiple battery cells are connected in series and parallel, the bus part 1a with internal threads is connected to the protruding portion. Threaded connection to electrically connect battery cells.

Figure 6 is an exploded schematic diagram of a battery cell provided by some embodiments of the present application.

As shown in FIG. 6 , the battery cell provided by the embodiment of the present application includes an electrode assembly 10 and a housing assembly 2 a. The electrode assembly 10 is accommodated in the housing assembly 2 a.

In some embodiments, the housing assembly 2a may also be used to contain an electrolyte, such as an electrolyte. The housing assembly 2a can be of various structural forms.

In some embodiments, the housing assembly 2a may include a housing 21 and an end cover assembly 20. The housing 21 is a hollow structure with one side open, and the end cover assembly 20 covers the opening of the housing 21 and forms a sealed connection. An accommodation cavity 210 for accommodating the electrode assembly 10 and the electrolyte is formed.

The housing 21 can be in various shapes, such as cylinder, rectangular parallelepiped, etc. The shape of the housing 21 can be determined according to the specific shape of the electrode assembly 10 . For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical shell can be used; if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped shell can be used.

In some embodiments, the end cap assembly 20 includes an end cap 23 that covers the opening of the housing 21 . The end cap 23 can be of various structures. For example, the end cap 23 can be a plate-like structure, a hollow structure with one end open, etc. For example, in FIG. 6 , the housing 21 has a rectangular parallelepiped structure, the end cover 23 has a plate-like structure, and the end cover 23 covers the opening at the top of the housing 21 .

The end cap 23 can be made of insulating material (such as plastic) or conductive material (such as metal). When the end cap 23 is made of metal material, the end cap assembly 20 may also include an insulating component located on the side of the end cap 23 facing the electrode assembly 10 to insulate the end cap 23 from the electrode assembly 10 .

In some embodiments, the end cap assembly 20 may also include electrode terminals 22 mounted on the end cap 23 . There are two electrode terminals 22 , and the two electrode terminals 22 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 10 to output the electric energy generated by the electrode assembly 10 .

In other embodiments, the housing assembly 2a can also be of other structures. For example, the housing assembly 2a includes a housing 21 and two end cover assemblies 20. The housing 21 is a hollow structure with openings on opposite sides, and an end cover assembly 20. 20 is correspondingly covered with an opening of the housing 21 and forms a sealed connection to form a receiving cavity 210 for accommodating the electrode assembly 10 and the electrolyte. In this structure, one end cover assembly 20 may be provided with two electrode terminals 22 and the other end cover assembly 20 may not be provided with any electrode terminal 22 , or the two end cover assemblies 20 may each be provided with one electrode terminal 22 .

In the battery cell, there may be one electrode assembly 10 accommodated in the case assembly 2a, or there may be a plurality of electrode assemblies 10. For example, in FIG. 6 , there are four electrode assemblies 10 .

From the appearance of the electrode assembly 10 , the electrode assembly 10 includes an electrode body 11 and a tab portion 12 connected to the electrode body 11 . Illustratively, the pole portion 12 extends from an end of the electrode body 11 close to the end cap assembly 20 .

In some embodiments, there are two pole tabs 12 , and the two pole tabs 12 are respectively defined as a positive pole tab and a negative pole tab. The positive electrode tab portion and the negative electrode tab portion may extend from the same end of the electrode body 11 , or may extend from opposite ends of the electrode body 11 .

The electrode body 11 is the core part of the electrode assembly 10 to realize the charging and discharging function, and the tab portion 12 is used to draw out the current generated by the electrode body 11 . The electrode body 11 includes a positive current collecting part of a positive current collector, a positive active material layer, a negative current collecting part of a negative current collector, a negative active material layer, and a separator. The positive electrode tab portion includes a plurality of positive electrode tabs, and the negative electrode tab portion includes a plurality of negative electrode tabs.

The tab portion 12 is used to electrically connect to the electrode terminal 22 . The tab portion 12 may be directly connected to the electrode terminal 22 through welding or other methods, or may be indirectly connected to the electrode terminal 22 through other components. For example, the electrode assembly 10 further includes a current collecting member 13 for electrically connecting the electrode terminal 22 and the tab portion 12 . There are two current collecting members 13 , and the two current collecting members 13 are respectively defined as a positive current collecting member and a negative current collecting member. The positive current collecting member is used to electrically connect the positive electrode terminal 22 and the positive electrode lug, and the negative current collecting member is used for electrically connecting the positive electrode terminal 22 and the positive electrode lug. To electrically connect the negative electrode terminal and the negative electrode lug. When a battery cell is provided with multiple electrode assemblies 10, the positive electrode current collecting members of the plurality of electrode assemblies 10 may be integrally provided, and the negative electrode current collecting members of the plurality of electrode assemblies 10 may be integrally provided.

Figure 7 is a partial cross-sectional schematic diagram of a battery cell provided by some embodiments of the present application. The battery cell in Figure 7 does not show the structure of the casing.

As shown in Figure 7, the battery cell includes an electrode assembly 10 and an end cover assembly 20. The electrode assembly 10 includes a tab portion 12. The end cover assembly 20 includes an electrode terminal 22 and an end cover 23. The end cover assembly 20 is provided with a through-end. The first through hole 231 of the cover 23, in which the electrode terminal 22 includes a main body part 221 and an extension part 222. The main body part 221 is fixedly installed on the end cover 23 and is disposed in the first through hole 231; the extension part 222 connects the main body part 221 and the first through hole 231. The extension portion 222 of the pole lug portion 12 is provided around the main body portion 221 and extends in a direction away from the axis of the first through hole 231 relative to the main body portion 221 . The extension portion 222 is provided on a side of the end cap 23 facing the electrode assembly 10 .

The first through hole 231 can be a through hole of various shapes, such as a cylindrical through hole, a rectangular through hole or a square through hole, etc. The first through hole 231 has a suitable size, and the specific opening position of the first through hole 231 should be Consider the arrangement form of the electrode assembly 10 .

The first through hole 231 may penetrate through the end cover 23 , and the axial dimension of the first through hole 231 may be higher than the axial dimension of the end cover 23 . In other words, the first through hole 231 may not only penetrate through the end cover 23 , but also Through other components connected to the end cap 23 . Of course, the axial size of the first through hole 231 may be substantially the same as the axial size of the end cover 23 .

The main body 221 may have various structures, for example, it may be a cylinder, a rectangular parallelepiped, a cube, etc., or it may be a combination of various shapes. The main part 221 is disposed in the first through hole 231, and its shape should match the first through hole 231. For example, if the first through hole 231 is a cylindrical through hole, then the main part 221 is a cylinder.

The main body 221 is made of conductive material, which can be metal materials such as copper, iron, aluminum, or an alloy material composed of multiple metal materials. Of course, it can also be other conductive materials. The main body 221 is fixedly installed on the end cover 23. Specifically, the main body 221 is disposed in the first through hole 231 of the end cover 23. The main body 221 can be in contact with the end cover 23. When the end cover 23 is made of insulating material, the main body 221 is disposed in the first through hole 231 of the end cover 23. The portion 221 can be in direct contact with the end cover 23; when the end cover 23 is made of conductive material, an insulating component can be provided between the main portion 221 and the end cover 23 to separate them and reduce the risk of electrical conduction between them. Of course, the main body 221 and the end cover 23 may not be in contact, that is, there is a gap between them. In this case, to ensure that the main body 221 is isolated from the end cover 23, the main body 221 may use other components and end caps. Cover 23 is connected.

The main part 221 is connected to the end cover 23, and the connection method can be various, such as welding, adhesive bonding, etc. If the end cover 23 and the main part 221 are both made of metal materials, the connection between the two should be coated with insulation. layer to prevent electrical conduction between the main body 221 and the end cap 23 .

The main body part 221 is connected to the extension part 222 . The extension part 222 is arranged around the main body part 221 and extends in a direction away from the axis of the first through hole 231 relative to the main body part 221 . The extension part 222 may have various shapes, for example, it may be a plate-like structure with a circular outer contour or a plate-like structure with a polygonal outer contour, etc. The extension length of the extension part 222 should not be too large, so as not to make the assembly of the extension part 222 too difficult; the extension length of the extension part 222 should not be too small. If the length is too small, the connection between the extension part 222 and the tab part 12 will be difficult. Difficulty.

The extension part 222 is connected to the main part 221 in a variety of ways, including direct connection, such as welding, or indirect connection, such as bonding with conductive adhesive. Of course, the two can also be an integrally formed structure. . The extension part 222 is also made of conductive material, which may be the same material as the main body part 221 or may be different. Optionally, the main body part 221 and the extension part 222 are an integrated structure made of alloy material.

The extension part 222 is disposed on the side of the end cap 23 facing the electrode assembly 10. The extension part 222 can be in contact with the end cap 23. When the end cap 23 is made of insulating material, the extension part 222 can be in direct contact with the end cap 23; When the cover 23 is made of conductive material, an insulating component can be provided between the extension portion 222 and the end cover 23 to separate them and reduce the risk of electrical conduction between them. Of course, there may be no contact between the extension part 222 and the end cover 23, that is, there may be a gap between them.

The pole lug portion 12 also has various structural forms. It can be a plate-shaped structure, a strip-shaped structure, etc., it can have bends, or it can be a columnar structure. The tab portion 12 is connected to the extension portion 222 in a variety of ways. For example, the tab portion 12 can be directly connected to the extension portion 222 through welding, or indirectly connected to the extension portion 222 through other components. The material of the pole part 12 and the extension part 222 may be the same or different. For example, the tab portion 12 and the extension portion 222 are made of the same material and are connected by welding. The tab portion 12 and the extension portion 222 of the same material can reduce the difficulty of welding and facilitate the welding operation.

Both the tab portion 12 and the extension portion 222 can be insulated from the end cover 23 to prevent the end cover 23 from being charged when the tab portion 12 and the extension portion 222 are energized, thereby reducing the risk of short circuits in the battery cells and improving the performance of the battery cells. Security and reliability.

According to the battery cell of the embodiment of the present application, the electrode terminal 22 has an extension part 222, and the extension part 222 is connected to the tab part 12, thereby increasing the contact area with the tab part 12, thereby improving the connection between the tab part 12 and the tab part 12. The overcurrent capability between the electrode terminals 22 further improves the charging and discharging performance of the battery cells. In addition, the increased contact area between the extension portion 222 and the tab portion 12 is also helpful in reducing the difficulty of connection, and the increased area of the connection area between the two can improve the stability of the connection, thereby improving the structural stability of the battery cell. sex.

Figure 8 is a partial enlarged view of the battery cell shown in Figure 7 at position A.

As shown in Figures 7 and 8, in some embodiments, the electrode assembly 10 further includes an electrode body 11, and the tab portion 12 includes a first portion 121 and a second portion 122 connected to each other. The projections of 122 along the axial direction of the first through hole 231 at least partially overlap, the first portion 121 is connected to the extension portion 222 , and the second portion 122 is connected to the electrode body 11 .

The electrode body 11 serves as the main structure of the electrode assembly 10 and can have various structural forms. For example, cylinder structure, cuboid structure or cube structure, etc. The electrode body 11 is the core part of the electrode assembly 10 to achieve the charging and discharging function. The tab portion 12 is used to draw out the current generated by the electrode body 11 . The electrode body 11 and the tab portion 12 are electrically connected.

The pole part 12 includes a first part 121 and a second part 122 that are connected to each other. The first part 121 and the second part 122 may be made of the same material or two different materials. The first part 121 and the second part 122 may be made of the same material. The second parts 122 are both electrically conductive. In some examples, the first part 121 and the second part 122 are both made of metal materials, and are welded therebetween. For example, the first part 121 and the second part 122 can form a laminated structure; of course, they can also form a bent structure, which can be determined according to specific production requirements.

In other examples, the first part 121 and the second part 122 are integral structures. The one-piece structure has good structural strength and can improve the structural strength of the tab portion 12, thereby improving the structural stability of the battery cell. Moreover, the one-piece structure can simplify production steps and improve production efficiency. The lug portion 12 formed by the first part 121 and the second part 122 may have a bent structure.

The first part 121 is connected to the extension part 222, and there are many ways of connection.

For example, the first part 121 may be connected to the side of the extension part 222 away from the end cap 23 , or the first part 121 may be connected to the side of the extension part 222 close to the end cap 23 , or the first part 121 and the extension part 222 may be connected along the edge. Direct contact in a direction perpendicular to the axial direction of the first through hole 231 enables conduction between the first part 121 and the extension part 222 regardless of the connection form.

As shown in FIGS. 7 and 8 , in some embodiments, the first part 121 includes a second through hole 121a disposed opposite to the first through hole 231 , the main part 221 extends to the second through hole 121a , and the extension part 222 connects On the side of the first portion 121 away from the end cover 23 .

The second through hole 121 a is arranged opposite to the first through hole 231 , and may have the same diameter as the first through hole 231 , or may have a different diameter than the first through hole 231 . For example, the second through hole 121a and the first through hole 231 have the same diameter, so that the main body 221 can have good matching with both the first through hole 231 and the second through hole 121a.

The first part 121 and the extension part 222 may have various matching relationships. In some examples, along the axial direction of the first through hole 231 , the projected portion of the extension portion 222 is located within the projection of the first portion 121 . It can be understood that the first part 121 is in contact with a part of the extension part 222, that is, the first part 121 is electrically connected to a part of the extension part 222. This arrangement can reduce the volume of the first part 121, thereby reducing the material cost of the tab part 12, and thereby reducing the material cost of the battery cell. In this application, the projection of the extension portion 222 means that the projection direction is the axial direction of the first through hole 231 , and the projection surface is a plane perpendicular to the axial direction of the first through hole 231 . The projection of the first part 121 means that the projection direction is the axial direction of the first through hole 231 , and the projection surface is a plane perpendicular to the axial direction of the first through hole 231 .

In other examples, as shown in FIG. 8 , along the axial direction of the first through hole 231 , the projection of the extension part 222 is located within the projection of the first part 121 , that is, the first part 121 can cover the entire extension part 222 , that is, the third One part 121 is electrically connected to the entire extension part 222 . The advantage of this arrangement is that the contact area between the first part 121 and the extension part 222 is further increased, thereby improving the overcurrent capacity between the tab part 12 and the electrode terminal 22, thereby improving the charging capacity of the battery cell. Discharge performance.

Figure 9 is a partial cross-sectional schematic view of a battery cell provided by other embodiments of the present application; Figure 10 is a partial enlarged view of the battery cell shown in Figure 9 at position B.

As shown in FIG. 9 , in some embodiments, the battery cell further includes a current collecting member 13 . The current collecting member 13 is disposed on the side of the end cover 23 facing the electrode assembly 10 , and the current collecting member 13 connects the extension 222 and the electrode. Ears 12. In some embodiments, the end cover 23 is made of insulating material, and the current collecting member 13 can be in contact with the end cover 23 . In other embodiments, the end cover 23 is made of conductive material, and an insulating component can be disposed between the current collecting member 13 and the end cover 23 to separate the current collecting member 13 and the end cover 23 to reduce the risk of electrical conduction between the two. .

The current collecting member 13 connects the extension part 222 and the tab part 12, and has electrical conductivity itself. The current collecting member 13 can be made of a variety of materials, and it can be the same as the material of the extension portion 222 or the tab portion 12 , or it can be different.

The current collecting member 13 can be of various structures, such as rectangular parallelepiped, cube, etc. Optionally, the current collecting member 13 has a plate-like structure. The plate-like structure has a smaller space occupation rate and can reduce the occupation of the accommodation space of the electrode assembly 10 .

The current collecting member 13 may have multiple connection methods for connecting the extension part 222 and the tab part 12 .

For example, the side of the current collecting member 13 facing the end cover 23 is connected to the extension portion 222 and the tab portion 12 at the same time;

Alternatively, the side of the current collecting member 13 facing away from the end cover 23 is connected to the extension portion 222 and the tab portion 12 at the same time;

Alternatively, the side of the current collecting member 13 facing the end cover 23 and the side away from the end cover 23 are respectively connected to the extension portion 222 and the tab portion 12 .

For example, in FIG. 10 , the side of the current collecting member 13 facing away from the end cover 23 is connected to the extending portion 222 and the tab portion 12 at the same time, that is, the tab portion 12 and the extending portion 222 are respectively connected to the side of the current collecting member 13 facing away from the end. One side of cover 23 is connected. The advantage of this arrangement is that it can save the space occupied by the three connections. Especially when there are multiple electrode assemblies 10 , each electrode assembly 10 includes a tab portion 12 . The overall structure formed by each tab portion 12 is relatively thick and occupies a large space inside the battery cell. Therefore, In this embodiment, the side of the current collecting member 13 away from the end cover 23 is connected to the extension portion 222 and the tab portion 12 at the same time, which can save the connection space of the three in the height direction of the battery cell, thereby making the electrode assembly 10 The overall space occupancy rate of the electrode body 11 is further increased, thereby improving the energy density of the battery cells.

Providing the current collecting member 13 in the battery cell can reduce the difficulty of directly connecting the tab portion 12 and the extension portion 222 . The reason is that when the tab part 12 and the extension part 222 are small in size, the contact area between them is also small, and the tab part 12 itself is not fixed, and the rocking of the tab part 12 during connection will increase the difficulty of connection. . By providing the current collecting member 13, first connecting the current collecting member 13 to the tab portion 12, and then connecting the current collecting member 13 to the extension portion 222, the difficulty of directly connecting the tab portion 12 and the extension portion 222 can be reduced.

As shown in FIGS. 9 and 10 , in some embodiments, the current collecting member 13 includes a third through hole 131 disposed opposite to the first through hole 231 , and the main body portion 221 extends to the third through hole 131 . The current collecting member 13 It is disposed on the side of the end cap 23 facing the electrode assembly 10 , and the current collecting member 13 connects the extending portion 222 and the tab portion 12 ; that is, the tab portion 12 and the extending portion 222 are connected to the same side of the current collecting member 13 .

The main body part 221 extends to the third through hole 131 of the current collecting member 13, which can increase the contact area between the current collecting member 13 and the extension part 222, thereby improving the current passing capacity between the tab part 12 and the electrode terminal 22. , thereby effectively improving the charge and discharge performance of the battery cell.

There may be various positional relationships between the current collecting member 13 and the extension portion 222 and the tab portion 12 .

In some examples, along the axial direction of the first through hole 231 , the projection of the extension portion 222 is located within the projection of the current collecting member 13 . It can be understood that at this time, the contact area between the current collecting member 13 and the extension portion 222 is larger, which can improve the current passing capacity between the current collecting member 13 and the electrode terminal 22 .

In other examples, along the axial direction of the first through hole 231 , at least part of the projection of the pole lug 12 is located within the projection of the current collecting member 13 . At this time, the contact area between the current collecting member 13 and the tab portion 12 is larger, which can improve the current passing capacity between the current collecting member 13 and the tab portion 12 . For example, the pole part 12 includes a first part 121 and a second part 122. The first part 121 of the pole part 12 is connected to the current collecting member 13, so the projection of the first part 121 is located within the projection of the current collecting member 13. , can significantly increase the connection area between the two, thereby improving the flow capacity between the two; in this case, because the second part 122 and the current collecting member 13 are not in direct contact, the second part 122 The projection may be partially located within the projection of the current collecting component 13 , or may be completely located within the projection of the current collecting component 13 . The projection position of the second part 122 has little or even negligible impact on the current flow capability. Alternatively, the pole lug portion 12 has a plate-like structure, and the projection of its entire structure is located within the projection of the current collecting member 13, thereby increasing the contact area between the two, thereby improving the current flow capacity between the two.

As shown in FIG. 11 , further, the pole portion 12 further includes a second through hole 121 a disposed opposite to the first through hole 231 , and the main body portion 221 extends to the second through hole 121 a and the third through hole 131 in sequence. The side of the member 13 facing the end cover 23 is connected to the pole lug portion 12 , and the side of the current collecting member 13 facing away from the end cover 23 is connected to the extension portion 222 .

It can be understood that the third through hole 131 is provided on the current collecting member 13, the second through hole 121a is provided on the pole portion 12, and the main body portion 221 is extended to the second through hole 121a and the third through hole 131 in sequence. Yes, on the basis of increasing the contact area between the current collecting member 13 and the extension part 222, the contact area between the current collecting member 13 and the tab part 12 is further increased, thereby improving the contact area between the pole part 12 and the pole part 12. The overcurrent capability between the current collecting members 13 further improves the overcurrent capability between the tab parts 12 and the electrode terminals 22 , thereby improving the charging and discharging performance of the battery cells.

As shown in FIGS. 10 and 11 , in some embodiments, the battery cell further includes an insulator 14 , the side of the extension 222 away from the end cover 23 is the first surface, and the insulator 14 at least covers the first surface.

The insulating member 14 can have a variety of structural shapes, such as a circular plate-like structure or a polygonal plate-like structure. The specific shape of the insulating member 14 can be set according to the shape of the extension part 222 so that the insulating part 14 can Has a good covering effect.

The insulating member 14 can be made of various materials, such as rubber, plastic or ceramic materials. Providing the insulator 14 on the extension part 222 can reduce the risk of foreign matter falling into the electrode assembly 10. For example, welding metal may be produced during welding between the tab part 12 and the extension part 222. The insulator 14 can reduce the risk to a certain extent. The risk of welding metal falling onto the electrode assembly 10 thus protects the electrode assembly 10 and improves the safety of the battery cells. The insulating member 14 also has an insulating effect and can reduce the possibility of breakdown between the electrode terminal 22 and the electrode assembly 10 .

Further, the main body part 221 includes a second surface that is flush with the first surface, and the insulating member 14 also covers the second surface.

The insulating member 14 covers the main body portion 221, further increasing the protection range of the electrode assembly 10, thereby ensuring the safety of the battery cells.

As shown in Figure 11, in any of the above embodiments, the main body 221 includes a connecting body 221b and a protruding portion 221a. The protruding portion 221a protrudes relative to the surface of the end cap 23 away from the electrode assembly 10, and the connecting body 221b is provided in the first through hole 231 and connects the protruding portion 221a and the extension portion 222, wherein at least part of the outer peripheral surface of the protruding portion 221a has an external thread.

Further, when the battery cells are used in batteries, when there are multiple battery cells, each battery cell includes a main body part 221, and the main body part 221 further includes a protruding part 221a, and the plurality of battery cells are connected in series. When connected in parallel, the battery cells are electrically connected by threading the bus part with internal threads to the protruding portion 221a.

Compared with the welding usually used in this field, the threaded connection has higher reliability and can reduce the possibility of disconnection or short circuit between bus components and battery cells due to false welding, thereby reducing the occurrence of short circuits when battery cells are connected in series and parallel. Or the probability of circuit breakage, which can improve the reliability and safety of battery cells connected in series and parallel.

As a specific embodiment of the present application, as shown in Figures 7 to 8, the battery cell includes an electrode assembly 10 and an end cover assembly 20. The electrode assembly 10 includes a tab portion 12 and an electrode body 11. The end cover assembly 20 includes an electrode terminal. 22 and the end cover 23. The end cover assembly 20 is provided with a first through hole 231 that penetrates the end cover 23. The electrode terminal 22 includes a main body part 221 and an extension part 222. The lug part 12 includes a first part 121 and a second part 122 connected to each other. The first part 121 includes a second through hole that is opposite to the first through hole 231. 121a, the main part 221 is disposed in the first through hole 231 and the second through hole 121a; the extension part 222 connects the main part 221 and the first part 121, and the extension part 222 is arranged around the main part 221 and faces away from the first part 221 relative to the main part 221. The through hole 231 extends in the direction of the axis, and the extension portion 222 is provided on the side of the first portion 121 away from the end cover 23 ; the second portion 122 is connected to the electrode body 11 .

In the battery cell of the embodiment of the present application, the main body part 221 passes through the first through hole 231 and the second through hole 121a in sequence, and the extension part 222 is connected to the first part 121, thereby increasing the distance between the extension part 222 and the first part 121. The contact area improves the overcurrent capability between the extension part 222 and the first part 121, thereby improving the overcurrent capability between the tab part 12 and the electrode terminal 22, thereby improving the charge and discharge performance of the battery cell.

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:

An electrode assembly (10) including a tab portion (12); and

An end cap assembly (20), which includes an electrode terminal (22) and an end cap (23). The end cap assembly (20) is also provided with a first through hole (231) penetrating the end cap (23), The electrode terminal (22) includes:

The main body part (221) is fixedly installed on the end cover (23) and is arranged in the first through hole (231);

Extension part (222), the extension part (222) connects the main body part (221) and the tab part (12), the extension part (222) is arranged around the main body part (221) and relative to The main body portion (221) extends in a direction away from the axis of the first through hole (231), and the extension portion (222) is provided on a side of the end cap (23) facing the electrode assembly (10). one side.
The battery cell according to claim 1, wherein

The electrode assembly (10) also includes an electrode body (11);

The pole part (12) includes a first part (121) and a second part (122) connected to each other. The first part (121) and the second part (122) are formed along the first through hole. The axial projections of (231) at least partially overlap, the first part (121) is connected to the extension part (222), and the second part (122) is connected to the electrode body (11).
The battery cell according to claim 2, wherein the first part (121) includes a second through hole (121a) arranged opposite to the first through hole (231), and the main body part (221) Extending to the second through hole (121a), the extension portion (222) is connected to a side of the first portion (121) away from the end cover (23).
The battery cell according to claim 2 or 3, wherein along the axial direction of the first through hole (231), the projection of the extension part (222) is located within the projection of the first part (121) .
The battery cell according to any one of claims 2 to 4, wherein the first part (121) and the second part (122) are of an integrated structure.
The battery cell according to claim 1, wherein

The battery cell includes a current collecting member (13), the current collecting member (13) includes a third through hole (131) opposite to the first through hole (231), and the main body portion (221) Extending to the third through hole (131), the current collecting member (13) is provided on the side of the end cover (23) facing the electrode assembly (10), and the current collecting member (13) Connect the extension part (222) and the lug part (12).
The battery cell according to claim 6, wherein the lug portion (12) includes a second through hole (121a) opposite to the first through hole (231), and the main body portion (221) Extending to the second through hole (121a), the side of the current collecting member (13) facing the end cover (23) is connected to the pole ear portion (12), and the current collecting member (13) ) is connected to the extension part (222) on a side away from the end cover (23).
The battery cell according to claim 6 or 7, wherein along the axial direction of the first through hole (231), the projection of the extension portion (222) is located within the projection of the current collecting member (13) .
The battery cell according to any one of claims 6 to 8, wherein along the axial direction of the first through hole (231), at least part of the projection of the tab portion (12) is located on the current collecting member. within the projection of (13).
The battery cell according to claim 6, wherein a side of the current collecting member (13) facing away from the end cover (23) is connected to the tab portion (12) and the extension portion (222) at the same time .
The battery cell according to claim 1, wherein

The extension part (222) includes a first surface, and the first surface is a surface of the extension part (222) facing away from the end cover (23);

The battery cell further includes an insulating member (14) covering at least the first surface.
The battery cell according to claim 11, wherein the main body part (221) includes a second surface flush with the first surface, and the insulating member (14) also covers the second surface.
The battery cell according to any one of claims 1 to 12, wherein the main body part (221) includes a protruding part (221a) and a connecting body (221b), and the protruding part (221a) is relative to the The surface of the end cap (23) away from the electrode assembly (10) protrudes, and the connection body (221b) is disposed in the first through hole (231) and connects the protruding portion (221a) and The extension part (222), wherein at least part of the outer peripheral surface of the protruding part (221a) has an external thread.
A battery including the battery cell according to any one of claims 1 to 13.
The battery according to claim 14, wherein

There are a plurality of battery cells, and each battery cell includes a main body (221). The main body (221) includes a protruding portion (221a). The outer peripheral surface of the protruding portion (221a) At least part of it has external threads;

The battery further includes a bus component (1a) connecting two adjacent battery cells, and the bus component (1a) has an internal thread matching the external thread of the protruding part (221a).
An electrical device includes the battery according to claim 14 or 15, wherein the battery is used to provide electrical energy.