WO2023173429A1

WO2023173429A1 - Battery cell, manufacturing method and manufacturing device therefor, battery, and electrical device

Info

Publication number: WO2023173429A1
Application number: PCT/CN2022/081791
Authority: WO
Inventors: 陈龙; 陈新祥; 林蹬华; 黄守君; 郑于炼; 王鹏; 金海族
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-03-18
Filing date: 2022-03-18
Publication date: 2023-09-21
Also published as: CN217788704U

Abstract

Embodiments of the present application provide a battery cell (20), a manufacturing method (300) and a manufacturing device (400) therefor, a battery (10), and an electrical device (1), used for improving the performance of a pressure relief mechanism (23) on the battery cell (20). The battery cell (20) comprises: a housing (21); multiple electrode assemblies (22) accommodated in the housing (21); and a pressure relief mechanism (23) arranged on a first wall (213) of the housing (21), the thickness of the first wall (213) being greater than the thickness of walls of the housing (21) other than the first wall (213), and the pressure relief mechanism (23) being used for discharging the internal pressure of the battery cell (20) when the internal pressure of the battery cell (20) exceeds a threshold value.

Description

Battery cells, manufacturing methods and manufacturing equipment, batteries, and electrical equipment

Technical field

The present application relates to the field of battery technology, and in particular to a battery cell and its manufacturing method and manufacturing equipment, batteries, and electrical equipment.

Background technique

Lithium-ion batteries have the advantages of small size, high energy density, long cycle life and long storage time. They are widely used in some electronic devices, electric vehicles and electric toys, such as in mobile phones, laptops and electric bicycles. , electric cars, electric planes, electric ships, electric toy cars, electric toy ships, electric toy planes and electric tools have been widely used.

With the continuous development of lithium-ion battery technology, higher requirements have been put forward for the safety performance of lithium-ion batteries. The pressure relief mechanism on lithium-ion batteries has an important impact on the safety performance of lithium-ion batteries. For example, when a lithium-ion battery undergoes short circuit, overcharge, etc., it may cause the internal thermal runaway of the lithium-ion battery and cause the internal air pressure to rise suddenly. At this time, a pressure relief mechanism is required to release the internal air pressure outward to prevent the lithium-ion battery from being damaged. explosion occurs. Therefore, the design of the pressure relief mechanism is extremely important.

Contents of the invention

This application provides a battery cell, its manufacturing method and manufacturing equipment, batteries, and electrical equipment to improve the performance of the pressure relief mechanism on the battery cell.

In a first aspect, a battery cell is provided, including: a casing; a plurality of electrode assemblies contained in the casing; and a pressure relief mechanism disposed on the first wall of the casing, the third The thickness of one wall is greater than the thickness of other walls on the housing except the first wall, and the pressure relief mechanism is used to release the battery cell when the internal pressure of the battery cell exceeds a threshold value. internal pressure of the body.

The battery cell of the present application includes multiple electrode assemblies, and a pressure relief mechanism is provided on the first wall of the casing of the battery cell. Since the thickness of the first wall is thicker than other walls, it not only improves the welding of the pressure relief mechanism Reliability, and the first wall is not easily deformed, so that the pressure relief mechanism is less affected by creep caused by internal pressure, and the burst pressure of the pressure relief mechanism is less affected by the creep, so that the pressure relief mechanism is less affected by creep. When the internal pressure is greater than the threshold, the internal pressure can be effectively released. At the same time, reducing the thickness of other walls also reduces the manufacturing cost of the housing 21 .

In one implementation, the thickness of the first wall is greater than or equal to 0.2 mm and less than or equal to 3 mm.

A larger thickness of the first wall will bring additional costs. A smaller thickness will easily cause the bursting pressure of the pressure relief mechanism to be affected by creep caused by the internal pressure of the battery cell. For this reason, its thickness should be set at an appropriate level. within the range, such as between 0.2mm and 3mm.

In one implementation, the thickness of other walls on the housing except the first wall is greater than or equal to 0.2 mm and less than or equal to 1 mm.

A larger thickness of the other walls on the casing except the first wall will bring additional costs, while a smaller thickness cannot ensure the structural stability of the battery cell. For this reason, the thickness of the other walls should be set within an appropriate range. within, such as between 0.2mm and 1mm.

In one implementation, the first wall is the bottom wall of the housing.

In this embodiment, the first wall on which the pressure relief mechanism is provided is the bottom wall of the housing. That is to say, the pressure relief mechanism is facing downwards. In this way, when the battery is placed under the seat of the vehicle, the pressure relief mechanism can be away from the passengers. , causing the internal pressure of the battery cells to be released downward, reducing the risk of injuries to passengers.

In one implementation, the thickness of the pressure relief mechanism at an effective position is smaller than the thickness of the housing, and the effective position is a preferentially opened position of the pressure relief mechanism.

In this embodiment, by setting the thickness of the effective position of the pressure relief mechanism to be smaller than the thickness of the casing, when the internal pressure of the battery cell is greater than the threshold, the pressure relief mechanism can be opened preferentially, thereby providing effective pressure relief. path.

In one implementation, the thickness of the pressure relief mechanism is greater than or equal to 0.01 mm and less than or equal to 0.5 mm.

When the thickness of the pressure relief mechanism is large, it may not be opened preferentially. When the thickness of the pressure relief mechanism is small, assembly difficulty increases and it is easily damaged during the assembly process. The thickness of the pressure relief mechanism should be set taking into account the internal pressure of the battery cell. Generally, it should match the above-mentioned threshold so that the pressure relief mechanism can be opened preferentially when the internal pressure of the battery cell exceeds the threshold. For example, setting the pressure relief mechanism The thickness of the mechanism is between 0.01mm and 0.5mm.

In one implementation, the pressure relief mechanism is provided with a notch, and the thickness of the pressure relief mechanism is the residual thickness of the notch.

In this embodiment, the pressure relief mechanism is provided with a notch. When the internal pressure of the battery cell exceeds the threshold, the pressure relief mechanism is preferentially opened through the notch. The manufacturing process is simple and has a better pressure relief effect. At this time, the thickness of the pressure relief mechanism is the residual thickness of the notch.

In one implementation, the battery cell is a rectangular parallelepiped, and the first wall is parallel to the length direction of the battery cell.

In this embodiment, the battery cell may be a rectangular parallelepiped. Since the shell of the battery cell is long, it is not conducive to releasing the internal pressure of the battery cell. Therefore, the pressure relief mechanism is arranged along the length of the battery cell. On the first wall with parallel directions, when the internal pressure of the battery cell exceeds the threshold, the pressure relief mechanism can form an effective path for the internal pressure to be released, which solves the problem that long battery cells are not easy to release pressure.

In a second aspect, a battery is provided, including a plurality of battery cells described in the first aspect or any implementation of the first aspect, and the battery cells are used to provide electrical energy.

In a third aspect, an electrical device is provided, including a plurality of battery cells described in the first aspect or any implementation of the first aspect, where the battery cells are used to provide electrical energy.

In a fourth aspect, a method for manufacturing a battery cell is provided, including: providing a case and a plurality of electrode assemblies, a first wall of the case being provided with a pressure relief mechanism, and the thickness of the first wall being greater than The thickness of other walls on the housing except the first wall, the pressure relief mechanism is used to release the internal pressure of the battery cell when the internal pressure of the battery cell exceeds a threshold; The plurality of electrode assemblies are contained in the housing.

In a fifth aspect, a battery cell manufacturing equipment is provided, including: providing a module for providing a housing and a plurality of electrode assemblies, a pressure relief mechanism is provided on the first wall of the housing, and the first The thickness of the wall is greater than the thickness of other walls on the housing except the first wall, and the pressure relief mechanism is used to release the battery cell when the internal pressure of the battery cell exceeds a threshold value. internal pressure; an assembly module for accommodating the plurality of electrode assemblies in the housing.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. Those of ordinary skill in the art can also obtain other drawings based on the drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application;

Figure 2 is a schematic structural diagram of a battery according to an embodiment of the present application;

Figure 3 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

Figure 4 is a schematic view of the first wall of the battery cell housing shown in Figure 3;

Figure 5 is a cross-sectional view of the battery cell shown in Figure 4 along the A-A direction;

Figure 6 is an enlarged view of the partial area B of the battery cell shown in Figure 5;

Figure 7 is a schematic structural diagram of a battery cell according to an embodiment of the present application;

Figure 8 is a schematic diagram of a release path of the internal pressure of a battery cell;

Figure 9 is an exploded diagram of a battery cell;

Figure 10 is a schematic structural diagram of an electrode assembly according to an embodiment of the present application;

Figure 11 is a schematic structural diagram of another electrode assembly according to an embodiment of the present application;

Figure 12 is a schematic structural diagram of yet another electrode assembly according to an embodiment of the present application;

Figure 13 is a schematic flow chart of a manufacturing method of a battery cell according to an embodiment of the present application;

FIG. 14 is a schematic block diagram of the battery cell manufacturing equipment according to the embodiment of the present application.

In the drawings, the drawings are not drawn to actual scale.

Detailed ways

The embodiments of the present application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

In the description of this application, it should be noted that, unless otherwise stated, "plurality" means more than two; the terms "upper", "lower", "left", "right", "inside", " The orientation or positional relationship indicated such as "outside" is only for the convenience of describing the present application and simplifying the description. It does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. Application restrictions. Furthermore, the terms "first," "second," "third," etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. "Vertical" is not vertical in the strict sense, but within the allowable error range. "Parallel" is not parallel in the strict sense, but within the allowable error range.

The directional words appearing in the following description are the directions shown in the figures and do not limit the specific structure of the present application. In the description of this application, it should also be noted that, unless otherwise clearly stated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, it can be a fixed connection or a removable connection. Detachable connection, or integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in this application may be understood depending on the specific circumstances.

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. .

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. The electrode assembly consists of a positive electrode plate, a negative electrode plate 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 current collector that is not coated with the positive electrode active material layer protrudes from the positive electrode collector that is coated with the positive electrode active material layer. Fluid, the positive electrode current collector without the positive electrode active material layer is used as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode 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. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector that is not coated with the negative electrode active material layer protrudes from the negative electrode collector that is coated with the negative electrode active material layer. Fluid, the negative electrode current collector that is not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can 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 isolation film can be polypropylene (PP) or polyethylene (polyethylene, PE). 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.

A pressure relief mechanism can be provided on the battery cell, which is used to release the internal pressure of the battery cell when the internal pressure of the battery cell reaches a threshold value. When the internal pressure of a battery cell reaches a threshold, a path for releasing the internal pressure can be formed through the pressure relief mechanism. The performance of the pressure relief mechanism directly affects the safety of the battery cells.

Usually, to facilitate manufacturing, the walls of the battery cell casing are of equal thickness. If the shell thickness is small, the burst pressure of the pressure relief mechanism is easily affected by creep caused by the internal pressure of the battery cell, thereby affecting its pressure relief performance; if the shell thickness is large, additional costs will be added.

To this end, embodiments of the present application provide a battery cell. The battery cell includes a plurality of electrode assemblies, and a pressure relief mechanism is provided on the first wall of the casing of the battery cell. By setting the thickness of the first wall Thicker than other walls, it can improve the welding reliability of the pressure relief mechanism and make the first wall less likely to deform, so that the pressure relief mechanism is less affected by creep caused by internal pressure, thereby reducing the bursting pressure of the pressure relief mechanism. Being less affected by the creep, the pressure relief mechanism can effectively relieve the internal pressure when the internal pressure is greater than the threshold. At the same time, reducing the thickness of other walls also reduces the manufacturing cost of the housing 21 .

The technical solutions described in the embodiments of this application are applicable to various electrical equipment using batteries.

Power-consuming devices can be vehicles, mobile 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 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 electrical equipment.

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

For example, as shown in Figure 1, it is a schematic structural diagram of a vehicle 1 according to an embodiment of the present application. The vehicle 1 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or a new energy vehicle. Extended range vehicles, etc. A motor 40 , a controller 30 and a battery 10 may be disposed inside the vehicle 1 . The controller 30 is used to control the battery 10 to provide power to the motor 40 . For example, the battery 10 may be disposed at the bottom, front or rear of the vehicle 1 . The battery 10 can be used to supply power to the vehicle 1 . For example, the battery 10 can be used as an operating power source of the vehicle 1 and used in the circuit system of the vehicle 1 , for example, to meet the power requirements for starting, navigation, and operation of the vehicle 1 . In another embodiment of the present application, the battery 10 can not only be used as an operating power source of the vehicle 1 , but also can be used as a driving power source of the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 . The battery 10 may also be referred to as a battery pack.

In order to meet different power requirements, the battery 10 may include multiple battery cells 20 , and the multiple battery cells 20 may be connected in series, parallel, or mixed, where mixed connection refers to a mixture of series and parallel.

For example, FIG. 2 shows a schematic structural diagram of a battery 10 according to an embodiment of the present application. The battery 10 may include multiple battery cells 20 . The battery 10 may also include a box 11. The inside of the box 11 is a hollow structure, and a plurality of battery cells 20 are accommodated in the box 11. Figure 2 shows a possible implementation of the box 11 in the embodiment of the present application. As shown in Figure 2, the box 11 may include two parts, here respectively referred to as the first box part 111 and the second box part. part 112, the first box part 111 and the second box part 112 are buckled together. The shapes of the first box part 111 and the second box part 112 may be determined according to the combined shapes of the plurality of battery cells 20 , and at least one of the first box part 111 and the second box part 112 has an opening. For example, as shown in FIG. 2 , both the first box part 111 and the second box part 112 may be hollow rectangular parallelepipeds and each has only one open surface. The opening of the first box part 111 and the second box part The openings of 112 are arranged oppositely, and the first box part 111 and the second box part 112 are interlocked to form the box 11 with a closed chamber.

For another example, unlike what is shown in FIG. 2 , only one of the first box part 111 and the second box part 112 may be a hollow rectangular parallelepiped with an opening, and the other may be plate-shaped to cover the opening. For example, here the second box part 112 is a hollow rectangular parallelepiped with only one surface as the opening surface, and the first box part 111 is plate-shaped, then the first box part 111 covers the opening of the second box part 112 to A box 11 is formed with a closed cavity that can be used to accommodate a plurality of battery cells 20 . A plurality of battery cells 20 are connected in parallel, in series, or in mixed combination, and then placed in the box 11 formed by fastening the first box part 111 and the second box part 112 .

In some embodiments, the battery 10 may also include other structures, which will not be described again here. For example, the battery 10 may further include a bus component, which is used to realize electrical connection between multiple battery cells 20 , such as parallel connection, series connection or mixed connection. Specifically, the bus component can realize electrical connection between the battery cells 20 by connecting the electrode terminals of the battery cells 20 . Furthermore, the bus part may be fixed to the electrode terminal of the battery cell 20 by welding. The electric energy of the plurality of battery cells 20 can be further drawn out through the box 11 through the conductive mechanism.

According to different power requirements, the number of battery cells 20 in the battery 10 can be set to any value. Multiple battery cells 20 can be connected in series, parallel or mixed connection to achieve larger capacity or power. Since the number of battery cells 20 included in each battery 10 may be large, in order to facilitate installation, the battery cells 20 are arranged in groups, and each group of battery cells 20 forms a battery module 200 . The number of battery cells 20 included in the battery module 200 is not limited and can be set according to requirements. That is to say, multiple battery cells 20 can directly form the battery 10, or they can first form a battery module, and then the battery modules can form the battery 10.

3 to 6 illustrate the battery cell 20 according to the embodiment of the present application. 4 is a schematic diagram of the first wall 213 of the housing 21 of the battery cell 20 shown in FIG. 3 . FIG. 5 is a cross-sectional view of the battery cell 20 shown in FIG. 4 along the direction A-A. FIG. 6 is an enlarged view of the partial area B of the battery cell 20 shown in FIG. 5 .

As shown in FIGS. 3 to 6 , the battery cell 20 in the embodiment of the present application includes a case 21 , a plurality of electrode assemblies 22 (not shown in FIGS. 3 to 6 ), and a pressure relief mechanism 23 . Among them, a plurality of electrode assemblies 22 are accommodated in the housing 21 . The pressure relief mechanism 23 is provided on the first wall 213 of the casing 21 . The thickness of the first wall 213 is greater than the thickness of other walls on the casing 21 except the first wall 213 . The pressure relief mechanism 23 is used to connect the battery cells. When the internal pressure of battery cell 20 exceeds the threshold, the internal pressure of battery cell 20 is released.

For the battery cell 20 in the embodiment of the present application, the thickness of the first wall 213 of the housing 21 is greater than the thickness of other walls on the housing 21 except the first wall 213 . For example, as shown in FIG. 5 , the thickness of the first wall 213 is greater than the thickness of the second wall 214 , the third wall 215 and the fourth wall 216 on the housing 21 except the first wall 213 .

Since the thickness of the first wall 213 on the housing 21 for arranging the pressure relief mechanism 23 is thicker than other walls on the housing 21 except the first wall 213 , the thicker first wall 213 makes the pressure relief mechanism 23 The welding reliability is higher, and the first wall 213 is not easily deformed, so that the pressure relief mechanism 23 is less affected by creep caused by internal pressure, and the bursting pressure of the pressure relief mechanism 23 is less affected by the creep. , so that the pressure relief mechanism 23 can effectively relieve the internal pressure when the internal pressure is greater than the threshold value. At the same time, reducing the thickness of other walls also reduces the manufacturing cost of the housing 21 .

A larger thickness of the first wall 213 will bring additional costs, and a smaller thickness will easily cause the bursting pressure of the pressure relief mechanism to be affected by creep caused by the internal pressure of the battery cell. For this reason, its thickness should be set at within the appropriate range. For example, in one implementation, the thickness of the first wall is greater than or equal to 0.2 mm and less than or equal to 3 mm.

A larger thickness of the other walls on the housing 21 except the first wall 213 will bring additional costs. A smaller thickness cannot ensure the structural stability of the battery cell 20. Therefore, the thickness of the other walls should also be set. within the appropriate range. For example, in one implementation, the thickness of other walls on the housing 21 except the first wall 213 is greater than or equal to 0.2 mm and less than or equal to 1 mm.

In one implementation, the thickness of the pressure relief mechanism 23 is smaller than the thickness of the housing 21 . The thickness of the pressure relief mechanism 23 is the thickness of the effective position of the pressure relief mechanism 23 . The effective position is the preferential opening position of the pressure relief mechanism 23 . . In this way, by setting the thickness of the pressure relief mechanism 23 to be smaller than the thickness of the case 21, when the internal pressure of the battery cell 20 is greater than the threshold, the pressure relief mechanism 23 can be opened preferentially, thereby providing an effective pressure relief path.

For example, as shown in FIGS. 5 and 6 , the thickness of the first wall 213 of the housing 21 is greater than the thickness of other walls on the housing 21 except the first wall 213 , and the thickness of the pressure relief mechanism 23 is smaller than the thickness of the first wall 213 of the housing 21 . The thickness of the other walls except the first wall 213. Assuming that the thicknesses of the pressure relief mechanism 23, the first wall 213, the second wall 214, the third wall 215 and the fourth wall 216 are T0, T1, T2, T3 and T4 respectively, then the thickness of the housing 22 and the pressure relief mechanism 23 The relationship between the thicknesses satisfies T0<T2=T3=T4<T1. Correspondingly, assuming that the maximum pressures that the pressure relief mechanism 23, the first wall 213, the second wall 214, the third wall 215 and the fourth wall 216 can withstand are P0, P1, P2, P3 and P4 respectively, then P0<P2 =P3=P4<P1.

It can be seen that when the above relationship is satisfied between the thickness of the case 22 and the thickness of the pressure relief mechanism 23, on the one hand, because the thickness of the pressure relief mechanism 23 is smaller than the thickness of other walls on the case 21, the internal pressure of the battery cell 20 When it is greater than the threshold, the pressure relief mechanism 23 can be opened preferentially, thereby providing an effective pressure relief path; on the other hand, increasing the thickness of the first wall 213 can improve the welding reliability of the pressure relief mechanism 23 on the first wall 213. Moreover, the first wall 213 is not easily deformed, so that the pressure relief mechanism 23 is less affected by creep caused by the internal pressure, and thus the bursting pressure of the pressure relief mechanism 23 is less affected by the creep, so that the pressure relief mechanism 23 The internal pressure can be effectively released when the internal pressure is greater than a threshold. At the same time, reducing the thickness of other walls also reduces the manufacturing cost of the housing 21 .

Here, the thickness of the pressure relief mechanism 23 is the thickness at the effective position of the pressure relief mechanism 23 , and the effective position is the preferential opening position of the pressure relief mechanism 23 . For example, in one implementation, as shown in FIG. 6 , a notch 231 is provided on the pressure relief mechanism 23 , and the thickness of the pressure relief mechanism 23 is the residual thickness of the notch 231 . When the internal pressure of the battery cell 20 exceeds the threshold, the pressure relief mechanism 23 is opened preferentially through the notch 231 , which has a simple manufacturing process and has a better pressure relief effect. At this time, the position of the notch 213 is the effective position of the pressure relief mechanism 23 , and the thickness of the pressure relief mechanism 23 is the residual thickness of the notch 213 .

The above description is based on the example in which the battery cell 20 includes a casing 21 and two end caps. In this case, the casing 21 includes four walls, of which the thickness of the first wall 213 is greater than the thickness of the other three walls. It should be understood that when the battery cell 20 includes a case 21 and an end cover, since the case 21 includes five walls, the thickness of the first wall 213 on which the pressure relief mechanism 23 is provided may be greater than the thickness of the other four walls.

The embodiment of the present application does not limit the form of the pressure relief mechanism 23 . The pressure relief mechanism 23 may be a component relatively independent of the first wall 213. For example, the first wall 213 is provided with an opening, the pressure relief mechanism 23 covers the opening, and the pressure relief mechanism 23 is provided with a notch 231; or, the pressure relief mechanism 23 is provided with a notch 231; The pressing mechanism 23 may also be a notch 231 directly formed on the first wall 213 .

In order to avoid the assembly process from affecting the pressure relief performance of the pressure relief mechanism 23, in one implementation, the pressure relief mechanism 23 is recessed in the first wall 213 of the housing 21, that is, buried in the first wall 213, so that During the assembly process of the pressure relief mechanism 23 and the housing 21, the impact of collision on the pressure relief mechanism 23 is avoided.

When the thickness of the pressure relief mechanism 23 is large, it may not be opened preferentially. When the thickness of the pressure relief mechanism 23 is small, assembly difficulty increases and the pressure relief mechanism 23 is easily damaged during the assembly process. The thickness of the pressure relief mechanism 23 should be set taking into account the internal pressure of the battery cell 20. Generally, it should match the above-mentioned threshold, so that the pressure relief mechanism can be opened preferentially when the internal pressure of the battery cell exceeds the threshold. For example, in one implementation, the thickness of the pressure relief mechanism 23 is greater than or equal to 0.01 mm and less than or equal to 0.5 mm.

In one implementation, as shown in FIG. 7 , the first wall 213 of the housing 21 is the bottom wall of the housing 21 . That is to say, the pressure relief mechanism 23 faces downward. In this way, when the battery 10 is placed under the seat of the vehicle 1, the pressure relief mechanism 23 can be away from the passengers, so that the internal pressure of the battery cell 20 is released downward, reducing the passenger's safety. Risk of harm.

The embodiment of the present application does not limit the number of multiple electrode assemblies 22 included in the battery cell 20 . For example, the battery cell 20 may include two electrode assemblies 22. In this case, the two electrode assemblies 22 may be arranged along the length direction The set of electrode assemblies 22 may be arranged along the thickness direction Y of the battery cell 20 , wherein each set of electrode assemblies 22 includes two electrode assemblies 22 arranged along the length direction X of the battery cell 20 ; for another example, the battery cell 20 may include There are more than two electrode assemblies 22 , and these electrode assemblies 22 are arranged along the length direction X of the battery cell 20 .

Hereinafter, the battery cell 20 according to the embodiment of the present application will be described taking the example that the battery cell 20 includes two electrode assemblies 22 and the two electrode assemblies 22 are arranged along the length direction X of the battery cell 20 .

The embodiment of the present application does not limit the shape of the battery cell 20. For example, the battery cell 20 may be a rectangular parallelepiped, which includes electrode assemblies 22 arranged along the length direction X.

When the battery cell 20 is a rectangular parallelepiped, since the casing 21 of the battery cell 20 is long, it is not conducive to releasing the internal pressure of the battery cell 20 . Therefore, in one implementation, the battery cell 20 is a rectangular parallelepiped, and the first wall 213 is parallel to the length direction X of the battery cell 20 . In this way, when the internal pressure of a battery cell exceeds the threshold, the pressure relief mechanism can form an effective path for releasing the internal pressure, solving the problem that long battery cells are difficult to release pressure.

When the battery cell 20 undergoes thermal runaway, its internal pressure will exceed the threshold. The pressure relief mechanism 23 can be activated when the internal pressure of the battery cell reaches the threshold to form a path for the internal pressure to be released to release the internal pressure. pressure, thereby reducing the risk of explosion of the battery cell 20 and improving the safety of the battery cell 20 .

In this embodiment, for example, as shown in FIGS. 8 and 9 , the pressure relief mechanism 23 may be disposed on the first wall 213 between the first electrode assembly 221 and the second electrode assembly 222 arranged along the length direction X. relative position of the area. In this way, when the internal pressure of the battery cell 20 reaches the threshold value, the path formed by the pressure relief mechanism 213 for the internal pressure to be released is shorter, which is conducive to pressure relief. The arrows in FIG. 8 represent the pressure relief path. When the internal pressure of the battery cell 20 is greater than the threshold, the pressure relief mechanism 23 is activated and releases the internal pressure to the battery cell 20 along the direction of the arrow. Externally, rapid pressure relief is achieved. The two square dashed boxes in FIG. 8 represent the first electrode assembly 221 and the second electrode assembly 222 respectively.

The above-mentioned “activation” means that the pressure relief mechanism 23 operates, so that the internal pressure of the battery cell 20 can be released. The actions caused by the pressure relief mechanism 23 include, but are not limited to, rupture, melting, splitting, etc. of at least a part of the pressure relief mechanism 23 . When the pressure relief mechanism 23 is activated, the internal pressure of the battery cell 20 will be released from the part where the pressure relief mechanism 23 is activated, and may carry high-temperature and high-pressure excretions, such as electrolyte, dissolved or split positive and negative materials. Fragments of pole pieces or separators, high-temperature and high-pressure gases or flames produced by reactions, etc.

In one implementation, two adjacent electrode assemblies 22 are electrically isolated from each other. For example, as shown in FIG. 5 , an insulating sheet 24 is provided between the first electrode assembly 221 and the second electrode assembly 222 to reduce the possibility of contact between the first electrode assembly 221 and the second electrode assembly 222 and reduce the risk of short circuit. , improving the safety of the battery cell 20 .

For example, as shown in FIG. 9 for the first electrode assembly 221, the tabs 2212 of the first electrode assembly 221 are disposed on the first end surface 223 of the first electrode assembly 221. The first end surface 223 is perpendicular to the length direction X and faces the battery cell. 20's exterior. The pole tab 2212 includes a first pole tab 2212a and a second pole tab 2212b, wherein one of the first pole tab 2212a and the second pole tab 2212b is a positive pole tab, and the other is a negative pole tab. Similarly, for the second electrode assembly 222, the tabs of the second electrode assembly 222 are disposed on the end surface of the second electrode assembly 222 that is perpendicular to the length direction Signal.

It can be seen that by locating the tabs of two adjacent electrode assemblies 22 at the two end surfaces of the battery cell 20 in the length direction X, it is convenient to connect the electrode terminals 214 of the battery cell 20 .

In one implementation, as shown in FIG. 9 , the housing 21 has a first opening 2211 and a second opening 2212 opposite along the length direction X of the battery cell 20 , and the battery cell 20 further includes a first end cover 2121 and a The second end cap 2122, the first end cap 2121 and the second end cap 2122 are respectively used to cover the first opening 2211 and the second opening 2212.

Since the casing 21 of the battery cell 20 has a first opening 2211 and a second opening 2212 along the length direction The first end cap 2121 and the second end cap 2122 of 2212 facilitate the insertion of the electrode assembly 22 into the case and simplify the assembly process of the battery cell 20 .

In one implementation, the two adjacent electrode assemblies 22 arranged along the length direction and a negative electrode terminal, used to draw out the electric energy of one of the two adjacent electrode assemblies 22; the second end cover 2122 is provided with a positive electrode terminal and a negative electrode terminal of the battery cell 20, used to draw out The electrical energy of the other electrode assembly 22 of the two adjacent electrode assemblies 22 .

Since the positive electrode terminal and the negative electrode terminal of the battery cell 20 are provided on both the first end cover 2121 and the second end cover 2122, that is, a set of electrode terminals is provided on both the first end cover 2121 and the second end cover 2122, and Adjacent electrode assemblies 2 arranged along the length direction The heat generated by the cell improves the charging and discharging performance of the battery cell 20 .

For example, as shown in FIG. 9 , a set of electrode terminals 214 of the battery cell 20 is provided on the first end cap 2121 , including a first electrode terminal 214 a and a second electrode terminal 214 b; similarly, a set of electrode terminals 214 on the second end cap 2122 is also provided. A set of electrode terminals 214 provided with the battery cell 20 includes a first electrode terminal 214a and a second electrode terminal 214b. For simplicity, the electrode terminal 214 on the second end cap 2122 is not shown in FIG. 9 . Among them, one of the first electrode terminal 214a and the second electrode terminal 214b is a positive electrode terminal, and the other is a negative electrode terminal. The electrode terminals 214 on the first end cap 2121 and the electrode terminals 214 on the second end cap 2122 can respectively conduct currents of the first electrode assembly 221 and the second electrode assembly 222 to reduce the current consumption of the first electrode assembly 221 and the second electrode assembly. The current flowing between 222 reduces the heat generated by the battery cell 20 and improves the charging and discharging performance of the battery cell 20 .

In one implementation, as shown in FIG. 9 , the housing 21 further includes a partition 25 covering the first wall 213 of the housing 21 to isolate the surfaces of the plurality of electrode assemblies 22 from the housing 21 .

In one implementation, as shown in FIG. 9 , the first wall 213 of the housing 21 is a wall with a smaller area on the housing 21 . During the charging process, the first electrode assembly 221 and the second electrode assembly 222 will expand and squeeze the separator 25 covering the first wall 23 , resulting in deformation of the separator 25 and further deformation of the pressure relief mechanism 23 . Among them, the smaller the area, the smaller the expansion force and the smaller the degree of deformation. Disposing the pressure relief mechanism 23 on the smaller first wall 213 of the housing 21 can reduce the deformation of the pressure relief mechanism 23 , reduce the risk of fatigue damage of the pressure relief mechanism 23 , and improve the safety of the battery cells 20 .

The embodiment of the present application does not limit the type of the electrode assembly 22 . For example, as shown in FIG. 10 , the electrode assembly 22 includes a first pole piece 224 and a second pole piece 225 . The first pole piece 224 and the second pole piece 225 are wound around a winding axis, and the winding axis is parallel to the battery. The length direction X of the monomer 20; as another example, as shown in FIG. The sheets 225 are alternately stacked along the second direction Y, and the second direction Y is perpendicular to the length direction X of the battery unit 20; for another example, as shown in FIG. piece 225, the first pole piece 224 includes a plurality of laminated sections 224a and a plurality of bent sections 224b, the bent sections 224b are used to connect two adjacent laminated sections 224a, the plurality of second pole pieces 225 and the plurality of laminated sections 224a are alternately stacked along the second direction Y, and the second direction Y is perpendicular to the length direction X of the electrode assembly 22 .

Since the winding axis of the first pole piece 224 and the second pole piece 225 of the electrode assembly 22 is parallel to the length direction X of the battery cell 20 , or the stacking direction of the first pole piece 224 and the second pole piece 225 of the electrode assembly 22 Perpendicular to its length direction X, therefore, most of the gas generated by the electrode assembly 22 is discharged along the end of the first pole piece in the length direction X and the end of the second pole piece in the length direction A gap for gas to pass through will be formed between the end in the direction X and the end of the second pole piece 225 along the length direction X. The pressure relief mechanism 23 is located on the first wall 213 at a position opposite to the area between the first electrode assembly 221 and the second electrode assembly 222 arranged along the length direction X. When the internal pressure of the battery cell 20 exceeds the threshold, the gas can Passing through the gap and acting on the pressure relief mechanism 23, the pressure relief mechanism 23 is actuated to relieve the internal pressure.

Among them, one of the first pole piece 224 and the second pole piece 225 is a positive pole piece, and the other is a negative pole piece. In Figures 10 and 11, the second pole piece 225 is the negative pole piece, and the first pole piece The piece 224 is a positive electrode piece as an example; FIG. 12 takes the second pole piece 225 as a positive electrode piece and the first pole piece 224 as a negative electrode piece as an example.

In one implementation, as shown in FIGS. 10 to 12 , the electrode assembly 22 further includes an isolation film 226 for insulating and isolating the first pole piece 224 and the second pole piece 225 .

In one implementation, the two tabs of the electrode assembly 22 are disposed on the first end face 223 of the electrode assembly 22 . The first end face 223 is perpendicular to the length direction X of the battery cell 20 . The poles of two adjacent electrode assemblies 22 The ears face in opposite directions, and both face the outside of the battery cell 20 .

In a possible specific implementation of the above-mentioned battery cell 20 , the pressure relief mechanism 23 on the battery cell 20 is provided on the first wall 213 of the housing 21 , and the first wall 213 is the bottom wall of the housing 21 . The pressure relief mechanism 23 is provided with notches 231 . The thickness of the first wall is greater than the thickness of other walls on the housing except the first wall, and the residual thickness of the notch 231 is smaller than the thickness of the housing 21 . The pressure relief mechanism 23 is located on the first wall 213 at a position opposite to the area between two adjacent electrode assemblies 22 arranged along the length direction X of the battery cell 20 .

Based on the above description, it can be seen that the pressure relief mechanism 23 on the battery cell 20 in the embodiment of the present application is provided on the first wall 213 of the housing 21. Since the thickness of the pressure relief mechanism 23 is smaller than the thickness of the housing 21, and the housing The thickness of the first wall 213 on the body 21 for arranging the pressure relief mechanism 23 is thicker than the other walls, which ensures that the pressure relief mechanism 23 can be opened preferentially to form an effective path for releasing the internal pressure, while also improving the The welding reliability of the pressure relief mechanism 23 improves the pressure relief performance of the battery cell 20, ensures the safety of the battery cell 20, and causes the first wall 213 to be affected by the internal pressure of the battery cell 20 during the pressure relief process. The influence of creep is small, ensuring the stability of the shell 21.

The above describes the battery cell 20, the battery 10 and the electrical equipment 1 of the embodiment of the present application. The manufacturing method and manufacturing equipment of the battery cell 20 of the embodiment of the present application will be described below. For the parts not described in detail, please refer to the foregoing. Various Examples.

FIG. 10 shows a schematic flow chart of a manufacturing method 300 of the battery cell 20 according to an embodiment of the present application. As shown in Figure 13, the method 300 includes: providing a housing 21 and a plurality of electrode assemblies 22. A pressure relief mechanism 23 is provided on the first wall 213 of the housing 21. The thickness of the first wall 213 is greater than the thickness of the first wall 213 of the housing 21. The pressure relief mechanism 23 is used to release the internal pressure of the battery cell 20 when the internal pressure of the battery cell 20 exceeds a threshold value; accommodate multiple electrode assemblies 22 in the case. Within the body 21.

FIG. 11 shows a schematic block diagram of the manufacturing equipment 400 of the battery cell 20 according to the embodiment of the present application. As shown in Figure 14, the device 400 includes: a providing module 410 for providing a housing 21 and a plurality of electrode assemblies 22. A pressure relief mechanism 23 is provided on the first wall 213 of the housing 21. The thickness of the first wall 213 is greater than The thickness of other walls on the housing 21 except the first wall 213. The pressure relief mechanism 23 is used to release the internal pressure of the battery cell 20 when the internal pressure of the battery cell 20 exceeds the threshold; the assembly module 420 , used to accommodate the plurality of electrode assemblies 22 in the housing 21 .

For the structure of the battery cell 20 manufactured by the above-mentioned manufacturing method 300 and manufacturing equipment 400, reference can be made to the battery cell 20 in each of the above implementations. For the sake of brevity, details will not be described here.

It should be noted that, as long as there is no conflict, the methods in the above implementations can be combined with each other.

While the present application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for components thereof without departing from the scope of the application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments 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 (20), including:

Shell(21);

A plurality of electrode assemblies (22) contained in the housing (21); and,

The pressure relief mechanism (23) is provided on the first wall (213) of the housing (21). The thickness of the first wall (213) is greater than the thickness of the first wall of the housing (21) except for the first wall. (213), the pressure relief mechanism (23) is used to release the internal pressure of the battery cell (20) when the internal pressure of the battery cell (20) exceeds a threshold. .
The battery cell (20) according to claim 1, wherein the thickness of the first wall (213) is greater than or equal to 0.2 mm and less than or equal to 3 mm.
The battery cell (20) according to claim 1 or 2, wherein the thickness of other walls on the housing (21) except the first wall (213) is greater than or equal to 0.2mm and less than or equal to 1mm.
The battery cell (20) according to any one of claims 1 to 3, wherein the first wall (213) is the bottom wall of the housing (21).
The battery cell (20) according to any one of claims 1 to 4, wherein the thickness of the effective position of the pressure relief mechanism (23) is smaller than the thickness of the housing (21), and the effective position of the pressure relief mechanism (23) is smaller than the thickness of the housing (21). The position is the preferential opening position on the pressure relief mechanism (23).
The battery cell (20) according to claim 5, wherein the thickness of the pressure relief mechanism (23) is greater than or equal to 0.01 mm and less than or equal to 0.5 mm.
The battery cell (20) according to claim 5 or 6, wherein the pressure relief mechanism (23) is provided with a notch (231), and the thickness of the pressure relief mechanism (23) is the thickness of the notch. (231) residual thickness.
The battery cell (20) according to any one of claims 1 to 7, wherein the battery cell (20) is a rectangular parallelepiped, and the first wall (213) is parallel to the length of the battery cell. Direction(X).
A battery (10) includes: a plurality of battery cells (20) according to any one of claims 1 to 8, the battery cells (20) being used to provide electrical energy.
An electrical device (10) includes: a plurality of battery cells (20) according to any one of claims 1 to 8, the battery cells (20) being used to provide electric energy.
A manufacturing method (300) for a battery cell (20), including:

A housing (21) and a plurality of electrode assemblies (22) are provided. A pressure relief mechanism (23) is provided on the first wall (213) of the housing (21). The thickness of the first wall (213) is greater than The thickness of other walls on the housing (21) except the first wall (213), the pressure relief mechanism (23) is used when the internal pressure of the battery cell (20) exceeds a threshold , releasing the internal pressure of the battery cell (20);

The plurality of electrode assemblies (22) are accommodated in the housing (21).
A manufacturing equipment (400) for battery cells (20), including:

A module (410) is provided for providing a housing (21) and a plurality of electrode assemblies (22). A pressure relief mechanism (23) is provided on the first wall (213) of the housing (21), and the third The thickness of one wall (213) is greater than the thickness of other walls on the casing (21) except the first wall (213), and the pressure relief mechanism (23) is used to operate on the battery cell (213). When the internal pressure of 20) exceeds the threshold, release the internal pressure of the battery cell (20);

An assembly module (420) is used to accommodate the plurality of electrode assemblies (22) in the housing (21).