WO2024040503A1

WO2024040503A1 - Electrode assembly, preparation method, battery cell, battery, and electrical apparatus

Info

Publication number: WO2024040503A1
Application number: PCT/CN2022/114740
Authority: WO
Inventors: 张加锡; 马云建; 高杰; 泉贵岭
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-08-25
Filing date: 2022-08-25
Publication date: 2024-02-29
Also published as: CN118696426A

Abstract

The application provides an electrode assembly, a preparation method, a battery cell, a battery and an electrical apparatus. The electrode assembly comprises an electrode body and a first tab. The electrode body comprises a plurality of first pole pieces and a plurality of second pole pieces. The polarity of the second pole pieces is opposite to that of the first pole pieces. The plurality of first pole pieces and the plurality of second pole pieces are alternately stacked, so as to increase the battery C-rate. Each first pole piece comprises a first current collector and a first coating. Each first current collector comprises a first empty foil area and a first coating area which are arranged in the extending direction of the first current collector, and the first coating area is coated with the first coating. The first tab is welded to the first empty foil areas of the plurality of first pole pieces, such that the welding process of the first tab and the first pole pieces is simplified, and the welding time of the first tab in the battery manufacturing process is shortened, so that the working efficiency is improved. The plurality of first empty foil areas is connected to one first tab, so that the space occupied by the first tab in the battery is reduced, the energy density of the battery is improved, and the battery performance is improved.

Description

Electrode assembly, preparation method, battery cell, battery and electrical device

Technical field

The present application relates to the field of batteries, and in particular to an electrode assembly, a preparation method, a battery cell, a battery and an electrical device.

Background technique

Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

In order to increase the charging and discharging speed of batteries, high-rate batteries are often used in the current market. Among them, high-rate batteries represent the charging and discharging capabilities of the battery compared to the ordinary rate. High-rate batteries are divided into discharge rate and charge rate. "C" is used to represent the ratio of battery charge and discharge current, that is, rate. However, the performance of high-rate batteries still needs to be improved.

Contents of the invention

In view of the above problems, this application provides an electrode assembly, a preparation method, a battery cell, a battery and a power device, which can improve battery performance.

In a first aspect, the present application provides an electrode assembly, including: an electrode body, including a plurality of first pole pieces and a plurality of second pole pieces; the second pole pieces are opposite in polarity to the first pole pieces; a plurality of first pole pieces are The pole pieces and a plurality of second pole pieces are alternately stacked. The first pole piece includes a first current collector and a first coating. The first current collector includes a first empty foil area and a first empty foil area arranged along the extending direction of the first current collector. A coating area, the first coating area is coated with the first coating; a first pole tab, the first pole tab is welded to the first empty foil areas of the plurality of first pole pieces.

In the solution of the embodiment of the present application, multiple first pole pieces and multiple second pole pieces are stacked alternately, the length of a single pole piece is reduced, the resistance of a single pole piece is reduced, and multiple pole pieces are connected in parallel, the internal resistance of the battery is reduced, and the battery The magnification is increased, and one first pole is welded to the first empty foil areas of multiple first pole pieces, which simplifies the welding process of the first pole and the first pole piece, and reduces the time required for welding the first pole during the battery manufacturing process. The required time is improved, and the work efficiency is improved, and multiple first empty foil areas are connected to one first tab, which reduces the space occupied by the first tab inside the battery, increases the energy density of the battery, and improves the battery performance.

In some embodiments, the second pole piece includes a second current collector and a second coating, the second current collector includes a second empty foil area and a second coating area arranged along the extending direction of the second current collector, and the second The coating area is coated with a second coating; wherein, the electrode assembly further includes a second tab, and the second tab is welded to the second empty foil areas of the plurality of second pole pieces.

In the above solution, one second tab is welded to the second empty foil areas of multiple second pole pieces, which simplifies the welding process of the second tab and the second pole piece and reduces the need for welding the second tab during the battery manufacturing process. The time required improves work efficiency, and multiple second empty foil areas are connected to one second tab, which reduces the space occupied by the second tab inside the battery, increases the energy density of the battery, and improves battery performance. .

In some embodiments, in the height direction of the electrode body, the first pole tab and the second pole tab are located on the same side of the electrode body, and the height direction of the electrode body intersects with the alternating stacking direction of the first pole piece and the second pole piece. .

In the above solution, the first tab and the second tab are located on the same side in the height direction of the electrode body. The first tab and the second tab occupy less space. The internal space utilization rate of the battery is high, and the battery energy density is high.

In some embodiments, in the width direction of the electrode body, the distance d between the first tab and the second tab is d≥5 mm, and the width direction of the electrode body intersects the height direction of the electrode body.

In the above solution, the distance d between the first pole and the second pole, d≥5mm, improves the problem of the first pole and the second pole being caused by the too small distance between the first pole and the second pole. connection, causing a battery short circuit problem.

In some embodiments, a plurality of first pole pieces and a plurality of second pole pieces are rolled to form an electrode body, one of the first pole tabs and the second pole tabs is located inside the electrode body, and the other is located inside the electrode body. outside the main body; alternatively, a plurality of first pole pieces and a plurality of second pole pieces are laminated to form an electrode body, and in the length direction of the electrode body, the first pole tabs and the second pole tabs are arranged on both sides of the electrode body, The length direction of the electrode body is perpendicular to the height direction of the electrode body and the stacking direction of the first pole piece and the second pole piece.

In the above solution, one of the first pole tab and the second pole tab is located inside the electrode body, and the other is located outside the electrode body, or the first pole tab and the second pole tab are arranged along the electrode body. On both sides in the length direction, there is a sufficient safety distance between the first pole and the second pole, which improves the problem of accidental conduction between the first pole and the second pole, causing a battery short circuit.

In some embodiments, the first pole tab and the second pole tab are located on both sides of the electrode body in the height direction of the electrode body, and the height direction of the electrode body intersects the stacking direction of the first pole piece and the second pole piece.

In the above scheme, when the first pole and the second pole are located on both sides in the height direction of the electrode body, there is a sufficient safety distance between the first and second poles, which improves the safety distance between the first and second poles. The problem of battery short circuit caused by ear connection improves the safety performance of the battery.

In some embodiments, the extension size of the first empty foil area in the height direction of the electrode body is smaller than that of the first coating area; and/or the extension size of the second empty foil area in the height direction of the electrode body is smaller than the second coating area; and/or, the first empty foil area and the second empty foil area are spaced apart in the height direction of the electrode body.

In the above solution, the extension size of the first empty foil area in the height direction of the electrode body is smaller than that of the first coating area; and/or, the extension size of the second empty foil area in the height direction of the electrode body is smaller than that of the second coating area. area; and/or, the first empty foil area and the second empty foil area are spaced apart in the height direction of the electrode body so that the first empty foil area and the second empty foil area avoid each other, so that the first tab and the second When the tabs are located on both sides of the electrode body in the height direction, the first empty foil area and the second empty foil area will not contact each other, causing a short circuit in the battery.

In some embodiments, a plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a winding structure, and the first pole tab and the second pole tab are located inside the winding structure or the first pole tab and the second pole The ears are located outside the winding structure; alternatively, a plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a laminate structure. In the length direction of the electrode body, the first pole tabs and the second pole tabs are located on the electrode body. On the same side, the length direction of the electrode body intersects with the height direction of the electrode body.

In the above solution, when the first tab and the second tab are located on the same side of the winding structure or the first tab and the second tab are located on the same side of the electrode body along the length direction, the process difficulty is low, and the tab is only Occupying the space on one side of the electrode assembly, the battery has high space utilization and high battery energy density.

In some embodiments, a plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a winding structure. One of the first pole tabs and the second pole tab is located inside the winding structure, and the other one is located inside the winding structure. Located outside the winding structure; alternatively, a plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a laminate structure. In the length direction of the electrode body, the first pole tab and the second pole tab are located on the electrode body. On both sides, the length direction of the electrode body intersects with the height direction of the electrode body.

In the above solution, one of the first pole and the second pole is located inside the winding structure, and the other is located outside the winding structure, or the first pole and the second pole are arranged along the edge of the electrode body. On both sides of its length direction, the linear distance between the first pole and the second pole is larger, which improves the safety distance between the first pole and the second pole caused by insufficient safety distance between the first pole and the second pole. The safety performance of the battery is improved due to the problem of battery short circuit due to accidental conduction of the ear.

In some embodiments, in the arrangement direction of the first empty foil area and the first coating area, the length of the first empty foil area is h1, where 3mm≤h1≤10mm; and/or, in the second empty foil area In the arrangement direction of the area and the second coating area, the length of the second empty foil area is h2, where 3mm≤h2≤10mm.

In the above scheme, in the arrangement direction of the first empty foil area and the first coating area, the length of the first empty foil area is h1, 3mm≤h1≤10mm, in the arrangement direction of the second empty foil area and the second coating area direction, the length of the second empty foil area is h2, 3mm≤h2≤10mm, which improves the problem that the first empty foil area and the second empty foil area are too short, causing the first empty foil area and the second empty foil area to be difficult to connect with the pole. lug connection, the problem that the pole lug is easy to fall off; at the same time, it also improves the problem that the first empty foil area and the second empty foil area are too long, leading to material waste and increased costs.

In some embodiments, the number of first pole pieces n1,2≤n1≤10.

In the above scheme, the number of first pole pieces is n1, 2 ≤ n1 ≤ 10, which improves the problem of too few first pole pieces and high battery impedance, resulting in reduced battery rate; it also improves the problem of too many first pole pieces. , the first empty foil area occupies too much internal space of the battery, resulting in the problem of reduced battery energy density.

In some embodiments, the first current collector is a composite foil in which a metal layer, a non-metal layer, and a metal layer are sequentially stacked along its own thickness direction; wherein, in the thickness direction of the composite foil, both sides of the composite foil are respectively First empty foil areas are formed, and additional foils are welded to each first empty foil area, and the additional foils located on both sides in the thickness direction of the composite foil are electrically connected to each other, and the additional foils on both sides in the thickness direction of the composite foil are At least one of them is welded to the first tab.

In the above solution, the first current collector is a composite foil. First empty foil areas are formed on both sides of the composite foil in the thickness direction. Additional foils are welded to each first empty foil area. The metal layer of the composite foil is Thin, by arranging additional foils and welding the additional foils to the first tabs, the welding reliability between the first pole pieces and the first tabs is improved, and the additional foils located on both sides in the thickness direction of the composite foil Electrically connected to each other, one of the additional foils on both sides in the thickness direction of the composite foil is welded to the first tab, which can simplify the welding steps of the additional foil and the first tab and improve work efficiency. The additional foil on the side is welded to the first pole, thereby improving the welding reliability of the additional foil and the first pole.

In some embodiments, in the thickness direction of the composite foil, the additional foil located on one side of the thickness of the composite foil is the first additional foil, and the additional foil located on the other side of the composite foil is the second additional foil; Wherein, the first additional foil material includes a first extended end extending out of the composite foil material, the second additional foil material includes a second extended end extending out of the composite foil material, and the first extended end extends out of the length of the composite foil material. It is greater than the length of the second extension end extending from the composite foil to form a welding portion for welding the first tab.

In the above solution, the length of the first extension end protruding from the composite foil is greater than the length of the second extension end protruding from the composite foil, so that when the first extension end and the first tab are welded, they will not be blocked by the second additional foil. Without obstruction, only the first extension end is connected to the first pole, which simplifies the welding steps of the first pole piece and the first pole and improves work efficiency.

In some embodiments, in a direction perpendicular to the arrangement direction of the first empty foil area and the first coating area, the width of the first empty foil area is D1, and the width of the first coating area is D, 0<D1≤ D/2, the width of the first empty foil area is the same as the second empty foil area.

In the above scheme, the width of the first empty foil area is D1, the width of the first coating area is D, 0<D1≤D/2, the width of the first empty foil area is the same as that of the second empty foil area, which improves the efficiency. The first empty foil area and the second empty foil area are too long, causing the first empty foil area and the second empty foil area to come into contact when the first pole piece and the second pole piece are alternately stacked, causing an internal short circuit problem in the battery, and The width of the first empty foil area is the same as that of the second empty foil area, so that the current paths of the first tab and the second tab are similar, balancing the internal resistance of the battery and improving battery performance.

In a second aspect, this application also provides a preparation method for preparing the electrode assembly mentioned in the first aspect, including:

Multiple first pole pieces and multiple second pole pieces are alternately stacked;

Welding the first pole tab and the plurality of first empty foil areas;

The first pole piece and the second pole piece are pressed together to form an electrode body.

In the preparation method provided by the embodiment of the present application, multiple first pole pieces and multiple second pole pieces are alternately stacked. Multiple pole pieces are connected in parallel to make it easier to complete large current discharge in a short time and increase the battery rate. The first pole The lug is welded to the first empty foil area of the plurality of first pole pieces, which simplifies the welding process of the first pole and the first pole piece, reduces the welding time of the first pole during the battery manufacturing process, and improves work efficiency. Moreover, multiple first empty foil areas are connected to one first tab, which reduces the space occupied by the first tab inside the battery, increases the energy density of the battery, and improves the battery performance.

In some embodiments, the step of arranging a plurality of first pole pieces and a plurality of second pole pieces in alternating stacks includes: arranging the first empty foil region and the second empty foil region to be located at the first pole piece at the first pole piece. An empty foil area and the first coating area are arranged on the same side in the direction.

In the above solution, the first empty foil area and the second empty foil area are located on the same side of the first pole piece. The first pole tab and the second pole tab occupy less space. The internal space utilization rate of the battery is high, and the battery energy density is high. .

In some embodiments, the step of arranging a plurality of first pole pieces and a plurality of second pole pieces in alternating stacks includes: arranging the first empty foil region and the second empty foil region to be located at the first pole piece at the first pole piece. An empty foil area and a first coating area are arranged on both sides in the direction.

In the above solution, the first empty foil area and the second empty foil area are located on both sides of the first pole piece, and there is a sufficient safety distance between the first pole tab and the second pole tab, which improves the safety of the first pole tab and the second pole tab. The ear accidentally turns on, causing the problem of battery short circuit and improving the safety performance of the battery.

In some embodiments, before the step of pressing the first pole piece and the second pole piece to form the electrode body, the step includes: winding the first pole piece and the second pole piece.

In the above scheme, the first pole piece and the second pole piece are wound to form an electrode winding body, which has low process difficulty and high preparation efficiency.

In a third aspect, embodiments of the present application provide a battery cell including a plurality of electrode assemblies according to any embodiment of the first aspect.

In a fourth aspect, embodiments of the present application provide a battery including a plurality of battery cells according to any embodiment of the third aspect.

In a fifth aspect, embodiments of the present application provide an electrical device, including the battery cell according to any embodiment of the third aspect, and the battery cell is used to provide electric energy.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are for the purpose of illustrating preferred embodiments only and are not to be construed as limiting the application. Also throughout the drawings, the same reference characters are used to designate the same components. In the attached picture:

Figure 1 is a schematic structural diagram of a vehicle provided by an embodiment of the present application;

Figure 2 is a schematic structural diagram of a battery pack provided by an embodiment of the present application;

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

Figure 4 is a schematic diagram of the exploded structure of a single battery provided by an embodiment of the present application;

Figure 5 is a schematic structural diagram of a pole piece of an electrode assembly provided by an embodiment of the present application;

Figure 6 is a top view of an electrode assembly provided by an embodiment of the present application;

Figure 7 is a front view of an electrode assembly provided by an embodiment of the present application;

Figure 8 is a top view of an electrode assembly provided by another embodiment of the present application;

Figure 9 is a schematic structural diagram of a pole piece of an electrode assembly provided by another embodiment of the present application;

Figure 10 is a front view of an electrode assembly provided by another embodiment of the present application;

Figure 11 is a top view of an electrode assembly provided by another embodiment of the present application;

Figure 12 is a bottom view of an electrode assembly provided by another embodiment of the present application;

Figure 13 is a top view of an electrode assembly provided by yet another embodiment of the present application;

Figure 14 is a bottom view of an electrode assembly provided by yet another embodiment of the present application;

Figure 15 is a front view of an electrode assembly provided by yet another embodiment of the present application;

Figure 16 is a top view of an electrode assembly provided by yet another embodiment of the present application;

Figure 17 is a bottom view of an electrode assembly provided by yet another embodiment of the present application;

Figure 18 is a front view of an electrode assembly provided by yet another embodiment of the present application;

Figure 19 is a top view of an electrode assembly provided by yet another embodiment of the present application;

Figure 20 is a bottom view of an electrode assembly provided by yet another embodiment of the present application;

Figure 21 is a front view of an electrode assembly provided by yet another embodiment of the present application;

Figure 22 is a schematic structural diagram of a pole piece of an electrode assembly provided by an embodiment of the present application;

Figure 23 is a schematic structural diagram of the first pole piece of an electrode assembly provided by yet another embodiment of the present application;

Figure 24 is a schematic structural diagram of a pole piece of an electrode assembly provided by an embodiment of the present application;

Figure 25 is a flow chart of a preparation method provided by an embodiment of the present application.

The reference numbers in the specific implementation are as follows:

1 vehicle, 2 battery, 101 motor, 102 controller, 202 box, 2021 first box part, 2022 second box part, 201 battery module, 3 battery cells, 4 shell;

5 electrode assembly, 51 electrode body, 52 pole tab, 521 first pole tab, 522 second pole tab, 53 first pole piece, 54 second pole piece, 531 first empty foil area, 532 first coating area, 533 first coating, 541 second empty foil area, 542 second coating area, 543 second coating, 5311 first connection area, 5312 first avoidance area, 5411 second connection area, 5412 second avoidance area, 55 composite foil, 56 additional foil, 561 first additional foil, 5611 first extension end, 562 second additional foil, 5621 second extension end, 57 pole piece, 58 first current collector, 59 second set fluid;

61 electrode terminals, 6 top cover components.

Detailed ways

The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and are therefore only used as examples and cannot be used to limit the protection scope of the present application.

It should be noted that, unless otherwise stated, the technical terms or scientific terms used in the embodiments of this application should have the usual meanings understood by those skilled in the art to which the embodiments of this application belong.

In the description of the embodiments of this application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back" , "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axis", "Diameter" The orientation or positional relationship indicated by “direction”, “circumferential direction”, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply the device or element referred to. It must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be construed as a limitation on the embodiments of the present application.

In addition, technical terms “first”, “second”, etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. In the description of the embodiments of this application, "plurality" means two or more, unless otherwise explicitly and specifically limited.

In the description of the embodiments of this application, unless otherwise explicitly stated and limited, technical terms such as "installation", "connection", "connection", and "fixing" should be understood in a broad sense. For example, it can be a fixed connection, or a fixed connection. It can be detachably connected or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary; it can be the internal connection of two elements or the interaction of two elements. relation. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

In the description of the embodiments of the present application, unless otherwise expressly provided and limited, a first feature "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in direct contact. Indirect contact through intermediaries. Furthermore, the terms "above", "above" and "above" the first feature is above the second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is higher in level than the second feature. "Below", "below" and "beneath" the first feature to the second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature has a smaller horizontal height than the second feature.

At present, judging from the development of the market situation, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles and electric cars, as well as in many fields such as military equipment and aerospace. . As the application fields of power batteries continue to expand, their market demand is also constantly expanding.

In this application, battery cells may include lithium ion secondary battery cells, lithium ion primary battery cells, lithium sulfur battery cells, sodium lithium ion battery cells, sodium ion battery cells or magnesium ion battery cells, etc., The embodiments of the present application are not limited to this. 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.

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 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.

As batteries become more and more widely used in people's daily lives, people have put forward higher requirements for the battery's rate. Through research, it was found that alternately stacking multiple pole pieces in the electrode assembly can effectively increase the battery rate.

The applicant noticed that multipolar sheet batteries have problems such as low energy density, high process difficulty, and low production efficiency.

In order to improve battery performance, the applicant found that a multi-pole battery is provided with multiple pole pieces, and each pole piece is provided with at least one pole tab. The ears will take up more space inside the battery, thereby reducing the energy density of the battery. Moreover, multiple tabs in multi-pole batteries require welding operations, which leads to problems of high process difficulty and low production efficiency.

Based on the above problems discovered by the inventor, the inventor improved the electrode assembly of the battery cell. The inventor has designed an electrode assembly. The electrode assembly includes an electrode body and a first tab. The electrode body includes a plurality of first pole pieces and a plurality of second pole pieces. The second pole pieces have opposite polarity to the first pole pieces. , a plurality of first pole pieces and a plurality of second pole pieces are alternately stacked, the first pole piece includes a first current collector and a first coating, the first current collector includes first electrodes arranged along the extending direction of the first current collector. An empty foil area and a first coating area, the first coating area is coated with a first coating; a first pole is welded to the first empty foil areas of a plurality of first pole pieces, simplifying the connection between the first pole and The welding process of the first pole piece reduces the time required to weld the first pole tab during the battery manufacturing process, improves work efficiency, and multiple first empty foil areas are connected to one first pole tab, reducing the number of first pole tabs inside the battery. The space occupied by one pole increases the energy density of the battery and improves the battery performance. The technical solutions described in the embodiments of this application are applicable to electrical devices using batteries.

Electrical 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 and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, for example, Electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, planers and more. The embodiments of this application impose no special restrictions on the above-mentioned electrical devices.

It should be understood that the technical solutions described in the embodiments of the present application are not limited to the batteries and electrical equipment described above, but can also be applied to all batteries including boxes and electrical equipment using batteries. However, for the sake of simplicity, the following The above-mentioned embodiments are all explained by taking an electric vehicle as an example.

Please refer to Figure 1 , which is a schematic structural diagram of a vehicle 1 provided by some embodiments of the present application. Vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. The vehicle 1 is provided with a battery 2 inside, and the battery may be provided at the bottom, head, or tail of the vehicle 1 . The battery 2 may be used to power the vehicle 1 , for example, the battery 2 may be used as an operating power source for the vehicle 1 . The vehicle 1 may also include a controller 102 and a motor 101. The controller 102 is used to control the battery to provide power to the motor 101, for example, for the starting, navigation and operating power requirements of the vehicle 1 during driving.

In some embodiments of the present application, the battery can not only be used as the operating power source of the vehicle 1 , but also can be used as the driving power source of the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .

In order to meet different power requirements, the battery 2 may include multiple battery cells. A battery cell refers to the smallest unit that constitutes a battery module or battery pack. Multiple battery cells may be connected in series and/or in parallel via electrode terminals for various applications. The battery 2 mentioned in this application includes a battery module or a battery pack. Among them, multiple battery cells can be connected in series, parallel, or mixed. Hybrid refers to a mixture of series and parallel. In the embodiments of the present application, multiple battery cells can be directly formed into a battery pack, or they can be formed into battery modules first, and then the battery modules can be formed into a battery pack.

Figure 2 shows a schematic structural diagram of a battery 2 according to an embodiment of the present application.

As shown in FIG. 2 , the battery includes a case 202 and battery cells (not shown), and the battery cells are accommodated in the case 202 .

The box 202 may be a single cuboid, a simple three-dimensional structure such as a cylinder or a sphere, or a complex three-dimensional structure composed of simple three-dimensional structures such as a cuboid, a cylinder or a sphere. The material of the box 202 may be alloy materials such as aluminum alloy, iron alloy, etc., or may be polymer materials such as polycarbonate, polyisocyanurate foam, or composite materials such as glass fiber and epoxy resin.

The box 202 is used to accommodate battery cells, and the box 202 can be of various structures. In some embodiments, the box body 202 may include a first box body part 2021 and a second box body part 2022. The first box body part 2021 and the second box body part 2022 cover each other. The first box body part 2021 and the second box body part 2022 cover each other. The two box portions 2022 jointly define an accommodation space for accommodating the battery cells 3 . The second box part 2022 may be a hollow structure with one end open, and the first box part 2021 may be a plate-like structure. The first box part 2021 is covered with the open side of the second box part 2022 to form a container with a receiving space. Box 202; the first box part 2021 and the second box part 2022 can also be hollow structures with one side open, and the open side of the first box part 2021 is covered with the open side of the second box part 2022, To form a box 202 with an accommodation space. Of course, the first box part 2021 and the second box part 2022 can be in various shapes, such as cylinder, rectangular parallelepiped, etc.

In order to improve the sealing performance after the first box part 2021 and the second box part 2022 are connected, a sealing member may also be provided between the first box part 2021 and the second box part 2022, such as sealant, sealing ring, etc. .

Assuming that the first box part 2021 is closed on the top of the second box part 2022, the first box part 2021 can also be called an upper box cover, and the second box part 2022 can also be called a lower box cover.

In the battery 2, 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 202; of course, multiple battery cells can also be connected in series or parallel first or A battery module 201 is formed by a mixed connection, and multiple battery modules 201 are connected in series, parallel, or mixed to form a whole, and are accommodated in a box 202 .

Figure 3 shows a schematic structural diagram of a battery module according to an embodiment of the present application.

In some embodiments, as shown in FIGS. 2 and 3 , there are multiple battery cells 3 , and the plurality of battery cells 3 are first connected in series, parallel, or mixed to form the battery module 201 . Multiple battery modules 201 are connected in series, parallel, or mixed to form a whole, and are accommodated in the box 202 .

The plurality of battery cells 3 in the battery module 201 can be electrically connected through bus components to achieve parallel, series or mixed connection of the plurality of battery cells 3 in the battery module 201 .

In this application, the battery cell 3 may include a lithium ion battery cell 3, a sodium ion battery cell 3, a magnesium ion battery cell 3, etc., which are not limited in the embodiments of this application. The battery cell 3 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 3 are generally divided into three types according to packaging methods: cylindrical battery cells 3, square battery cells 3 and soft-pack battery cells 3. The embodiments of the present application are not limited to this, and may especially refer to soft-pack batteries. Cell 3, or in other words, among the series of products corresponding to the soft pack battery cell 3, the battery cell 3 in the embodiment of the present application has better performance. However, for the sake of simplicity of description, the following embodiments take the prismatic battery cell 3 as an example.

Figure 4 is a schematic structural diagram of a battery cell 3 provided by some embodiments of the present application. The battery cell 3 refers to the smallest unit that makes up the battery. As shown in FIG. 4 , the battery cell 3 includes a top cover assembly, a case 4 and an electrode assembly 5 .

The electrode assembly 5 is a component in the battery cell 3 where electrochemical reactions occur. One or more electrode assemblies 5 may be contained within the housing 4 . The electrode assembly 5 is mainly formed by winding or stacking pole pieces. The pole pieces are divided into positive electrode pieces and negative electrode pieces, and a separator is usually provided between the positive electrode piece and the negative electrode piece. The pole piece includes a current collector and an active material coating coated on the surface of the current collector. The positive electrode current collector can be one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy. The positive electrode active material coating can be lithium cobalt oxide or iron phosphate. Lithium, ternary lithium or lithium manganate, etc. The negative electrode current collector can be one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, iron or iron alloy, and the negative electrode active material coating can be carbon or silicon. The uncoated portions of the positive electrode current collector and the negative electrode current collector each constitute tabs 52 . The positive electrode tab and the negative electrode tab can be located together at one end of the main body or respectively located at both ends of the main body. During the charging and discharging process of the battery, the positive active material coating and the negative active material coating react with the electrolyte, and the tabs 52 are connected to the electrode terminals 61 to form a current loop.

The housing 4 is a component used to cooperate with the top cover assembly 6 to form an internal environment of the battery cell 3 , wherein the formed internal environment can be used to accommodate the electrode assembly 5 , electrolyte (not shown in the figure) and other components. . The housing 4 and the top cover assembly 6 may be independent components, and an opening may be provided on the housing 4. The top cover assembly 6 covers the opening at the opening to form the internal environment of the battery cell 3. Alternatively, the top cover assembly 6 and the housing 4 can also be integrated. Alternatively, the top cover assembly 6 and the shell 4 can form a common connection surface before other components are put into the shell. When the inside of the shell 4 needs to be sealed, the top cover assembly 6 can be closed with the shell 4. The housing 4 can be of various shapes and sizes, such as rectangular parallelepiped, cylinder, hexagonal prism, etc. The shape of the housing 4 can be determined according to the specific shape and size of the electrode assembly 5 . The housing 4 can be made of a variety of materials. In some embodiments, the housing 4 is made of copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

In some embodiments, as shown in FIG. 4 , two electrode terminals 61 may be provided in the top cover assembly 6 . One electrode terminal 61 of the top cover assembly 6 is electrically connected to one tab 52 (for example, the positive tab) of the electrode assembly 5 . The other electrode terminal 61 in the top cover assembly 6 is electrically connected to the other tab 52 of the electrode assembly 5 (for example, the negative tab).

In other embodiments, the number of openings of the housing 4 may be two. Two openings are provided on opposite sides of the housing 4 . There are two top cover assemblies 6 . The two top cover assemblies 6 cover the two openings of the housing 4 respectively. In this case, the number of electrode terminals 61 in the top cover assembly 6 may be one. The electrode terminal 61 in one top cover assembly 6 is electrically connected to one tab 52 (for example, the positive tab) of the electrode assembly 5; the electrode terminal 61 of the other top cover assembly 6 is electrically connected to the other tab 52 (for example, the positive tab) of the electrode assembly 5. negative ear) electrical connection.

Please refer to FIGS. 5 and 6 . FIG. 5 is a schematic structural diagram of the pole piece 57 of an electrode assembly 5 provided by an embodiment of the present application. FIG. 6 is a top view of an electrode assembly 5 provided by an embodiment of the present application.

As shown in Figures 5 and 6, the electrode assembly 5 in the embodiment of the present application includes an electrode body 51 and a first tab 521. The electrode body 51 includes a plurality of first pole pieces 53 and a plurality of second pole pieces 54. The second pole piece 54 has the opposite polarity to the first pole piece 53. A plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked. The first pole piece 53 includes a first current collector 58 and a first coating. 533. The first current collector 58 includes a first empty foil area 531 and a first coating area 532 arranged along the extending direction of the first current collector 58. The first coating area 532 is coated with the first coating 533; a first One pole tab 521 is welded to the first empty foil areas 531 of the plurality of first pole pieces 53 .

When the first pole piece 53 and the second pole piece 54 are wound and arranged, the extending direction of the first current collector 58 points to the winding direction of the first pole piece 53 . When the first pole piece 53 and the second pole piece 54 are stacked, the extending direction of the first current collector 58 points in a direction intersecting with the stacking direction of the first pole piece 53 and the second pole piece 54 .

In some embodiments, the first pole piece 53 is a positive pole piece, and the second pole piece 54 is a negative pole piece, or the first pole piece 53 is a negative pole piece, and the second pole piece 54 is a positive pole piece.

In some embodiments, each first empty foil region 531 has the same shape and area.

In some embodiments, the welding method may be laser welding, microwave welding, friction welding, etc.

In the solution of the embodiment of the present application, multiple first pole pieces 53 and multiple second pole pieces 54 are stacked alternately, the length of a single pole piece 57 is reduced, and the resistance of a single pole piece 57 is reduced. Multiple pole pieces 57 are connected in parallel, and the battery The internal resistance decreases, the battery rate increases, and one first tab 521 is connected to a plurality of first empty foil areas 531, which simplifies the welding process of the first tab 521 and the first pole piece 53, and reduces the number of first steps in the battery manufacturing process. The welding time of the tab 531 improves the work efficiency, and multiple first empty foil areas 531 are connected to one first tab 521, which reduces the space occupied by the first tab 521 inside the battery and improves the energy density of the battery. , improved battery performance.

In some embodiments, as shown in FIGS. 5 and 6 , the second pole piece 54 includes a second current collector 59 and a second coating 543 . The second current collector 59 includes electrodes arranged along the extending direction of the second current collector 59 . The second empty foil area 541 and the second coating area 542, the second coating area 542 is coated with the second coating 543; wherein, the electrode assembly 5 also includes a second tab 522, and the second tab 522 is connected with a plurality of The second empty foil area 541 of the second pole piece 54 is welded.

When the first pole piece 53 and the second pole piece 54 are wound and arranged, the extending direction of the second current collector 59 points to the winding direction of the second pole piece 54 . When the first pole piece 53 and the second pole piece 54 are stacked, the extension direction of the second current collector 59 points to the direction in which the stacking directions of the first pole piece 53 and the second pole piece 54 intersect.

In some embodiments, each second empty foil region 541 has the same shape and area.

In some embodiments, the shape and area of each first empty foil area 531 and the second empty foil area 541 are the same; in some embodiments, the first tab is connected to the second tab at the connection position of the first empty foil area. The connection position in the second empty foil area is the same.

In these embodiments, one second tab 522 is welded to a plurality of second empty foil areas 541, which simplifies the welding process of the second tab 522 and the second pole piece 54, and reduces the need for welding the second pole during the battery manufacturing process. The time required for the lug 522 is improved, and the plurality of second empty foil areas 541 are connected to one second lug 522, which reduces the space occupied by the second lug 522 inside the battery and improves the energy density of the battery. Improved battery performance.

Please refer to FIG. 7 , which is a front view of an electrode assembly 5 provided by an embodiment of the present application.

In some embodiments, as shown in FIGS. 6 and 7 , the first tab 521 and the second tab 522 are located on the same side of the electrode body 51 in the height direction of the electrode body 51 . The alternating stacking directions of the first pole pieces 53 and the second pole pieces 54 intersect.

In the height direction of the electrode body 51 , the first tab 521 and the second tab 522 are located on the same side of the electrode body 51 , which means that in the height direction of the electrode body 51 , the first tab 521 and the second tab 522 are located on the same side of the electrode body 51 . 522 protrudes from the electrode body 51 from the same side of the electrode body 51 .

In some embodiments, the height direction of the electrode body 51 is the X direction.

In some embodiments, when the first pole piece 53 and the second pole piece 54 are wound and arranged, the direction in which the first pole piece 53 and the second pole piece 54 are alternately stacked refers to the direction in which the first pole piece 53 and the second pole piece 54 are alternately stacked. The winding of the pole piece 54 forms an electrode winding body in a direction diverging from its center to its edge.

In these embodiments, the first tab 521 and the second tab 522 are located on the same side in the height direction of the electrode body 51. The first tab 521 and the second tab 522 occupy less space, and the internal space utilization of the battery is high. , the battery energy density is high.

Please refer to FIG. 8 , which is a top view of an electrode assembly 5 provided by another embodiment of the present application.

In some embodiments, as shown in FIGS. 6 to 8 , in the width direction of the electrode body 51 , the distance d between the first tab 521 and the second tab 522 , d ≥ 5 mm, the width of the electrode body 51 The direction Z intersects the height direction X of the electrode body 51 .

In some embodiments, the width direction of the electrode body 51 is the Z direction.

In some embodiments, the distance d between the first tab 521 and the second tab 522 in the width direction of the electrode body 51 is 5mm≤d≤100mm, and 100mm refers to the electrode assembly provided in the embodiment of the present application. 5 is more suitable for electrode bodies with a width of no more than 100mm. However, in practical applications, relevant technicians can set the width direction Z of the electrode body 51 according to the actual width of the electrode body 51. The first tab 521 and the second pole The distance d between the ears 522 is the maximum value.

In some embodiments, the distance d between the first tab 521 and the second tab 522 in the width direction of the electrode body 51 is 10 mm ≤ d ≤ 50 mm. The distance between the tabs 522 is too small, causing the first tab 521 and the second tab 522 to be connected, resulting in a short circuit problem in the battery. Because the problem of overcurrent in the tab 52 and battery heating is taken into account, the electrode assembly 5 provided in the embodiment of the present application has a better effect in the electrode body 51 with a width not exceeding 50 mm, so in the width direction Z of the electrode body 51 , the distance between the first pole tab 521 and the second pole tab 522 does not exceed 50mm.

In these embodiments, the distance d between the first pole 521 and the second pole 522, d≥5mm, improves the problem of the first pole caused by the too small distance between the first pole 521 and the second pole 522. The lug 521 and the second lug 522 are connected, causing the problem of battery short circuit.

In some embodiments, as shown in FIGS. 6 to 8 , a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are rolled to form an electrode body 51 , and the first pole tabs 521 and the second pole tabs 522 are One of them is located inside the electrode body 51 and the other is located outside the electrode body 51; or, a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are stacked to form the electrode body 51. direction, the first tab 521 and the second tab 522 are disposed on both sides of the electrode body 51 , and the length direction of the electrode body 51 is perpendicular to the height direction X of the electrode body 51 and the first pole piece 53 and the second pole piece 54 the stacking direction.

The first pole piece 53 and the second pole piece 54 are wound into an electrode winding body. The inner part refers to the part wound first in time sequence during the winding process of the electrode winding body, and the outer part refers to the electrode winding body. During the body winding process, the part is wound later in time sequence than the inner part.

In some embodiments, the length direction of the electrode body 51 is the Y direction.

In some embodiments, the first tab 521 or the second tab 522 located outside the electrode body is connected to the outermost first empty foil area 531 or the second empty foil area 541 and is away from other first empty foil areas 531 or one side of the second empty foil area 541 , thereby improving the problem of the tab 52 hurting or crushing the first empty foil area 531 or the second empty foil area 541 .

In some embodiments, in the direction in which the first pole piece 53 and the second pole piece 54 are stacked, the first pole tab 521 and the second pole tab 522 located outside the electrode body 51 are arranged diagonally. There is a sufficient safety distance between 521 and the second pole lug 522, which improves the safety performance of the battery.

In these embodiments, one of the first tab 521 and the second tab 522 is located inside the electrode body 51 and the other is located outside the electrode body 51 , or the first tab 521 and the second tab 522 are located outside the electrode body 51 . The ears 522 are arranged on both sides of the electrode body 51 along the length direction Y. There is a sufficient safety distance between the first pole 521 and the second pole 522, which improves the accidental conduction of the first pole 521 and the second pole 522. connected, causing a battery short circuit problem.

Please refer to Figures 9 and 10. Figure 9 is a schematic structural diagram of the pole piece 57 of an electrode assembly 5 provided by another embodiment of the present application. Figure 10 is a top view of an electrode assembly 5 provided by another embodiment of the present application. .

In some embodiments, as shown in FIGS. 9 and 10 , the first tab 521 and the second tab 522 are located on both sides of the electrode body 51 in the height direction X of the electrode body 51 . X intersects the stacking direction of the first pole piece 53 and the second pole piece 54 .

In these embodiments, when the first tab 521 and the second tab 522 are located on both sides of the electrode body 51 in the height direction X, there is a sufficient safety distance between the first tab 521 and the second tab 522, which improves The connection between the first tab 521 and the second tab 522 causes the problem of battery short circuit, which improves the safety performance of the battery.

In some embodiments, as shown in FIGS. 9 and 10 , the extension size of the first empty foil area 531 in the height direction X of the electrode body 51 is smaller than the first coating area 532 ; and/or, the second empty foil area The extension size of 541 in the height direction

In some embodiments, the first empty foil area 531 includes a first connection area 5311 and a first escape area 5312, and the second empty foil area 541 includes a second connection area 5411 and a second escape area 5412. The first connection area 5411 is used to connect the first tab 521 , and the second connection area 5411 is used to connect the second tab 522 . The area of the first avoidance area 5312 is not smaller than the second connection area 5411. The first avoidance area 5312 is used to avoid the second connection area 5411. By setting the first avoidance area 5312, multiple second connection areas 5411 will not be affected when they are connected to each other. The first empty foil area 531 is obstructed. The area of the second avoidance area 5412 is not smaller than the first connection area 5311. The second avoidance area 5412 is used to avoid the first connection area 5311. By setting the second avoidance area 5412, multiple first connection areas 5311 will not be affected when they are connected to each other. The second empty foil area 541 is obstructed.

In some embodiments, in the height direction 542 length.

In some embodiments, in the height direction X of the electrode body 51 , the first empty foil area 531 and the second empty foil area 541 are not overlapped.

In some embodiments, in the height direction X of the electrode body 51, one end of the first empty foil area 531 is flush with the first coating area 532; in the height direction One end is flush with the second coating area 542.

In some embodiments, in the height direction half the length.

In these embodiments, the extension size of the first empty foil area 531 in the height direction X of the electrode body 51 is smaller than that of the first coating area 532; and/or, the second empty foil area 541 extends in the height direction The extended dimension on the surface is smaller than the second coating area 542; and/or, the first empty foil area 531 and the second empty foil area 541 are spaced apart along the height direction so that the first empty foil area 531 and the second empty foil area 541 avoid each other. position, so that when the first tab 521 and the second tab 522 are located on both sides of the electrode body 51 in the height direction X, the first empty foil area 531 and the second empty foil area 541 will not contact each other, causing a short circuit of the battery.

Please refer to Figures 11 to 15. Figure 11 is a top view of an electrode assembly 5 provided by another embodiment of the present application. Figure 12 is a bottom view of an electrode assembly 5 provided by another embodiment of the present application. Figure 13 is a A top view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 14 is a bottom view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 15 is an electrode provided in yet another embodiment of the present application. Front view of component 5.

In some embodiments, as shown in FIGS. 10 to 15 , a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a winding structure, and the first pole tabs 521 and the second pole tabs 522 are located in the winding structure. The inner side of the winding structure or the first pole tab 521 and the second pole tab 522 are located outside the winding structure, or a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a laminate structure. In the length direction Y of the electrode body 51 , the first tab 521 and the second tab 522 are located on the same side of the electrode body 51 , and the length direction Y of the electrode body 51 intersects with the height direction X of the electrode body 51 .

In these embodiments, when the first tab 521 and the second tab 522 are located on the same side of the wound structure or the first tab 521 and the second tab 522 are located on the same side in the length direction Y of the electrode body 51 , the process difficulty is low, the tab 52 only occupies the space on one side of the electrode assembly 5, the battery space utilization is high, and the battery energy density is high.

Please refer to Figures 16 to 21. Figure 16 is a top view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 17 is a bottom view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 18 is a A front view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 19 is a top view of an electrode assembly 5 provided in yet another embodiment of the present application. Figure 20 is an electrode provided in yet another embodiment of the present application. Bottom view of assembly 5. Figure 21 is a front view of an electrode assembly 5 provided by yet another embodiment of the present application.

In some embodiments, as shown in FIGS. 16 to 21 , a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a winding structure, and one of the first pole tabs 521 and the second pole tabs 522 One is located inside the winding structure, and the other is located outside the winding structure, or a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a laminate structure, in the length direction Y of the electrode body 51 On the electrode body 51 , the first tab 521 and the second tab 522 are located on both sides of the electrode body 51 , and the length direction Y of the electrode body 51 intersects with the height direction X of the electrode body 51 .

In these embodiments, one of the first tab 521 and the second tab 522 is located inside the winding structure, and the other is located outside the winding structure, or the first tab 521 and the second tab 522 are located outside the winding structure. 522 is disposed on both sides of the electrode body 51 along its length direction Y. The linear distance between the first tab 521 and the second tab 522 is larger, which improves the distance between the first tab 521 and the second tab 522. Insufficient safety distance causes the first tab 521 and the second tab 522 to be accidentally connected, causing the battery to short-circuit, thereby improving the safety performance of the battery.

Please refer to Figure 22. Figure 22 is a schematic structural diagram of the pole piece 57 of an electrode assembly 5 provided by an embodiment of the present application.

In some embodiments, as shown in Figure 22, in the arrangement direction of the first empty foil area 531 and the first coating area 532, the length of the first empty foil area 531 is h1, 3mm≤h1≤10mm; and/ Or, in the arrangement direction of the second empty foil area 541 and the second coating area 542, the length of the second empty foil area 541 is h2, 3mm≤h2≤10mm.

In some embodiments, the length h1 of the first empty foil area 531 is equal to the length h2 of the second empty foil area 541.

In these embodiments, in the arrangement direction of the first empty foil area 531 and the first coating area 532, the length of the first empty foil area 531 is h1, 3mm≤h1≤10mm, and in the second empty foil area 541 and the first empty foil area 541 In the arrangement direction of the two coating areas 542, the length of the second empty foil area 541 is h2, 3mm≤h2≤10mm, which improves the problem that the first empty foil area 531 and the second empty foil area 541 are too short, causing the first empty foil area to be too short. The area 531 and the second empty foil area 541 are not easily connected to the tab 52, and the tab 52 is easy to fall off; it also improves the problem that the first empty foil area 531 and the second empty foil area 541 are too long, resulting in material waste and increased costs. The problem.

In some embodiments, as shown in FIG. 22 , the number of first pole pieces 53 is n1, 2≤n1≤10.

In some embodiments, the number of second pole pieces 54 is equal to the number of first pole pieces 53 .

In these embodiments, the number of first pole pieces 53 is n1, 2 ≤ n1 ≤ 10, which improves the problem of too few first pole pieces 53 and high battery impedance, resulting in reduced battery rate; it also improves There are too many pole pieces 53 and the first empty foil area 531 occupies too much space inside the battery, resulting in a problem of reduced battery energy density.

Please refer to FIG. 23. FIG. 23 is a schematic structural diagram of the first pole piece 53 of an electrode assembly provided by yet another embodiment of the present application.

In some embodiments, as shown in FIG. 23 , the first current collector 58 is a composite foil 55 in which a metal layer, a non-metal layer, and a metal layer are sequentially stacked along its own thickness direction; wherein, in the thickness direction of the composite foil 55 On both sides of the composite foil 55, first empty foil areas 531 are respectively formed. Additional foils 56 are welded to each first empty foil area 531, and the additional foils 56 are located on both sides of the composite foil 55 in the thickness direction. Electrically connected to each other, at least one of the additional foils 56 on both sides of the composite foil 55 in the thickness direction is welded to the first tab 521 .

In some embodiments, the first current collector 58 is an aluminum foil and the second current collector 59 is a copper foil.

In some embodiments, the first current collector 58 is a composite foil 55 with a "sandwich" structure, and the second current collector 59 is a copper foil.

When the first tab 521 is directly welded to the metal layer, the welding quality is poor because the area of the first tab 521 is small and the metal layer is thin. Therefore, when the first tab 521 is directly welded to the metal layer, the welding quality is poor.

In some embodiments, the additional foil 56 has a larger area than the first empty foil area 531 . The additional foil material 56 covers the first empty foil area 531 to ensure the connection reliability of the additional foil material 56 and the first empty foil area 531 .

In some embodiments, the thickness of the additional foil 56 is greater than the thickness of the metal layer, and the first tab 521 is welded to the additional foil 56 .

Since the composite foil 55 is provided with a non-metallic layer, the non-metallic layer insulates the metal layers on both sides of it from each other. Therefore, additional foils 56 are provided on both sides of the first empty foil area 531 in the thickness direction and the additional foils on both sides are The material 56 is electrically conductive to ensure that the metal layers on both sides of the composite foil material 55 are electrically conductive.

In these embodiments, the first current collector 58 is a composite foil 55. First empty foil areas 531 are formed on both sides of the composite foil 55 in the thickness direction. Additional foils are welded to each first empty foil area 531. material 56, the metal layer of the composite foil material 55 is thin, by providing an additional foil material 56, and welding the additional foil material 56 to the first pole tab 521, the reliability of the welding between the first pole piece 53 and the first pole tab 521 is improved. property, and the additional foils 56 located on both sides of the composite foil 55 in the thickness direction are electrically connected to each other. One of the additional foils 56 on both sides of the composite foil 55 in the thickness direction is welded to the first tab 521, which can simplify the additional foils. The welding step of the material 56 and the first tab 521 improves work efficiency. The additional foils 56 on both sides of the thickness direction of the composite foil 55 are welded to the first tab 521 to improve the welding of the additional foil 56 and the first tab 521. reliability.

In some embodiments, as shown in Figure 23, in the thickness direction of the composite foil 55, the additional foil 56 located on one side of the thickness of the composite foil 55 is a first additional foil 561, which is located on the other side of the composite foil 55 The additional foil material 56 is a second additional foil material 562; wherein, the first additional foil material 561 includes a first extended end 5611 extending from the composite foil material 55, and the second additional foil material 562 includes a first extension end 5611 extending from the composite foil material 55. The length of the second extension end 5621 of the first extension end 5611 extending out of the composite foil 55 is greater than the length of the second extension end 5621 extending out of the composite foil 55 to form a welding portion for welding the first tab 521 5612.

In these embodiments, the length of the first extension end 5611 extending from the composite foil 55 is greater than the length of the second extension end 5621 extending from the composite foil 55 , so that when the first extension end 5611 and the first tab 521 are welded It will not be hindered by the second extension end 5621, and only the first extension end 5611 is connected to the first pole tab 521, which simplifies the welding steps of the first pole piece 53 and the first pole tab 521, and improves work efficiency.

Please refer to FIG. 24 , which is a schematic structural diagram of the pole piece 57 of an electrode assembly provided by an embodiment of the present application.

In some embodiments, as shown in Figure 24, in a direction perpendicular to the arrangement direction of the first empty foil area 531 and the first coating area 532, the width of the first empty foil area 531 is D1, and the width of the first coating area 531 is D1. The width of 532 is D, 0<D1≤D/2, and the width of the first empty foil area 531 is the same as the second empty foil area 541.

In these embodiments, the width of the first empty foil area 531 is D1, the width of the first coating area 532 is D, 0<D1≤D/2, the width of the first empty foil area 531 is the same as the width of the second empty foil area. 541 is the same, which improves the problem that the first empty foil area 531 and the second empty foil area 541 are too long, resulting in the first empty foil area 531 and the second empty foil area being alternately stacked when the first pole piece 53 and the second pole piece 54 are stacked alternately. The areas 541 are in contact with each other, and the problem of short circuit inside the battery, and the width of the first empty foil area 531 is the same as the second empty foil area 541, makes the current paths of the first tab 521 and the second tab 522 similar, balancing the internal resistance of the battery. , improve battery performance.

Please refer to Figure 25, which is a flow chart of a preparation method provided by an embodiment of the present application.

As shown in Figures 19 to 25, this application also provides a preparation method for preparing the electrode assembly 5 mentioned in the above embodiment. The preparation method includes:

Step S01: Alternately stack multiple first pole pieces 53 and multiple second pole pieces 54;

Step S02: Weld the first tab 521 and the plurality of first empty foil areas 531;

Step S03: Press the first pole piece 53 and the second pole piece 54 to form the electrode body 51.

In the preparation method provided by the embodiment of the present application, multiple first pole pieces 53 and multiple second pole pieces 54 are alternately stacked. Multiple pole pieces 57 are connected in parallel to make it easier to complete large current discharge in a short time, improving the battery rate. , the first pole tab 521 is connected to the first empty foil areas 531 of the plurality of first pole pieces 53, which simplifies the welding process of the first pole tab 521 and the first pole piece 53, and reduces the need for welding the first pole during the battery manufacturing process. The time required for the lug 521 is improved, and the working efficiency is improved, and multiple first empty foil areas 531 are connected to one first tab 521, which reduces the space occupied by the first tab 521 inside the battery and improves the energy density of the battery. Improved battery performance.

In some embodiments, as shown in Figures 19 to 25, step S01 includes making the first empty foil area 531 and the second empty foil area 541 located in the first pole piece 53 between the first empty foil area 531 and the second empty foil area. A coating area 532 is arranged on the same side in the direction.

In these embodiments, the first empty foil area 531 and the second empty foil area 541 are located on the same side of the first pole piece 53. The first pole tab 521 and the second pole tab 522 occupy less space, and the internal space of the battery is utilized. High efficiency and high battery energy density.

In some embodiments, as shown in FIGS. 19 to 25 , step S02 includes making the first empty foil area 531 and the second empty foil area 541 located in the first pole piece 53 between the first empty foil area 531 and the second empty foil area 531 . A coating area 532 is arranged on both sides in the direction.

In these embodiments, the first empty foil area 531 and the second empty foil area 541 are located on both sides of the first pole piece 53, and there is a sufficient safety distance between the first pole tab 521 and the second pole tab 522, which improves the performance of the first pole piece 53. The first tab 521 and the second tab 522 are accidentally connected, causing a short circuit problem in the battery and improving the safety performance of the battery.

In some embodiments, as shown in FIGS. 19 to 25 , before step S03 , it includes: winding the first pole piece 53 and the second pole piece 54 .

In these embodiments, the first pole piece 53 and the second pole piece 54 are wound to form an electrode winding body, which has a simple process and high preparation efficiency.

According to some embodiments of the present application, the present application also provides a battery cell, including the electrode assembly of any of the above solutions.

According to some embodiments of the present application, the present application also provides a battery, including the battery cell of any of the above solutions.

According to some embodiments of the present application, the present application also provides an electrical device, including a battery cell according to any of the above solutions, and the battery cell is used to provide electrical energy to the electrical device.

The power-consuming device can be any of the aforementioned devices or systems using battery cells.

As shown in Figures 1 to 23, this application provides an electrode assembly 5. The electrode assembly 5 includes an electrode body 51 and a tab 52. The electrode body 51 includes a plurality of first pole pieces 53 and a plurality of second pole pieces 54. , the second pole piece 54 has the opposite polarity to the first pole piece 53. A plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked. The first pole piece 53 includes a first current collector 58 and a first coating layer. Layer 533, the first current collector 58 includes a first empty foil area 531 and a first coating area 532 arranged along the extending direction of the first current collector 58, the first coating area 532 is coated with the first coating 533; The diode piece 54 includes a second current collector 59 and a second coating 543. The second current collector 59 includes a second empty foil area 541 and a second coating area 542 arranged along the extending direction of the second current collector 59. The coating area 542 is coated with a second coating 543; the pole tab 52 includes a first pole tab 521 and a second pole tab 522, a first pole tab 521 and a plurality of first empty foils of the first pole pieces 53 The area 531 is welded, and a second pole tab 522 is welded to the second empty foil areas 541 of the plurality of second pole pieces 54 .

In the height direction X of the electrode body 51 , the first tab 521 and the second tab 522 are located on the same side of the electrode body 51 . The height direction intersect, the plurality of first pole pieces 53 and the plurality of second pole pieces 54 are wound to form the electrode body 51. One of the first pole tabs 521 and the second pole tabs 522 is located inside the electrode body 51, and the other one is located inside the electrode body 51. Located outside the electrode body 51; alternatively, a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are stacked to form the electrode body 51, and the first pole tabs 521 and the second pole tabs 522 are arranged along the length of the electrode body 51. On both sides in the direction Y, the length direction Y of the electrode body 51 is perpendicular to the height direction X of the electrode body 51 and the stacking direction of the first pole piece 53 and the second pole piece 54. In the width direction Z of the electrode body 51, the The distance d between the first tab 521 and the second tab 522 is 10 mm ≤ d ≤ 50 mm, and the width direction Z of the electrode body 51 intersects the height direction X of the electrode body 51 .

In the height direction The width of an empty foil area 531 is D1, the width of the first coating area 532 is D, 0<D1≤D/2, the width of the first empty foil area 531 is the same as the second empty foil area 541; multiple first The pole piece 53 and a plurality of second pole pieces 54 are alternately stacked to form a winding structure. The first pole tab 521 and the second pole tab 522 are arranged inside the winding structure or the first pole tab 521 and the second pole tab 522 are arranged inside the winding structure. On the outside of the winding structure, or a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked. In the length direction Y of the electrode body 51, the first pole tabs 521 and the second pole tabs 522 are arranged on the electrode. On one side of the body 51, the length direction Y of the electrode body 51 intersects the height direction X of the electrode body 51, or a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a winding structure. One of the ears 521 and the second pole ears 522 is located inside the winding structure, and the other is located outside the winding structure, or a plurality of first pole pieces 53 and a plurality of second pole pieces 54 are alternately stacked to form a roll. The first tab 521 and the second tab 522 are arranged on both sides of the electrode body 51 along its length direction Y. The length direction Y of the electrode body 51 intersects with the height direction X of the electrode body 51 .

The length h1 of the first empty foil area 531 in its extension direction, 3mm≤h1≤10mm, and the length h2 of the second empty foil area 541 in its extension direction, 3mm≤h2≤10mm;

The number of first pole pieces 53 is n1, 2≤n1≤10, and the number of second pole pieces 54 is equal to the number of first pole pieces 53.

The first current collector 58 is a composite foil 55 in which a metal layer, a non-metal layer, and a metal layer are sequentially stacked along the thickness direction of the composite foil 55; wherein, in the thickness direction of the composite foil 55, two sides of the composite foil 55 are respectively formed. The first empty foil areas 531 have additional foils 56 welded to each first empty foil area 531 respectively, and the additional foils 56 located on both sides of the composite foil 55 in the thickness direction are electrically connected to each other, and the two sides of the composite foil 55 in the thickness direction are electrically connected. One of the additional foils 56 is welded to the first tab 521 .

As shown in Figures 1 to 24, this application also provides a preparation method, which includes:

Let a plurality of first pole pieces 53 and a plurality of second pole pieces 54 be stacked alternately;

Let the first empty foil area 531 and the second empty foil area 541 be located on the same side or both sides of the first pole piece 53 in the arrangement direction of the first empty foil area 531 and the first coating area 532;

Weld the first tab 521 and the plurality of first empty foil areas 531;

The first pole piece 53 and the second pole piece 54 are pressed together to form the electrode body 51 .

In the electrode assembly of the embodiment of the present application, multiple first pole pieces 53 and multiple second pole pieces 54 are stacked alternately, the length of a single pole piece 57 is reduced, the resistance of a single pole piece 57 is reduced, and multiple pole pieces 57 are connected in parallel. , the internal resistance of the battery decreases, the battery rate increases, and one first tab 521 is connected to a plurality of first empty foil areas 531, which simplifies the welding process of the first tab 521 and the first pole piece 53, and reduces the time required in the battery manufacturing process. The welding time of the first tab 531 improves the work efficiency, and multiple first empty foil areas 531 are connected to one first tab 521, which reduces the space occupied by the first tab 521 inside the battery and improves the performance of the battery. Energy density improves battery performance.

In the preparation method of the embodiment of the present application, multiple first pole pieces 53 and multiple second pole pieces 54 are stacked alternately. Multiple pole pieces 57 are connected in parallel to make it easier to complete large current discharge in a short time, thereby improving the battery rate. The first pole tab 521 is connected to the first empty foil areas 531 of the plurality of first pole pieces 53, which simplifies the welding process of the first pole tab 521 and the first pole piece 53, and reduces the need for welding the first pole tab during the battery manufacturing process. 521 time required, improves work efficiency, and multiple first empty foil areas 531 are connected to one first tab 521, reducing the space occupied by the first tab 521 inside the battery, improving the energy density of the battery, and improving improved battery performance.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be equivalently replaced; and these modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present application. The scope shall be covered by the claims and description of this 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

An electrode assembly, characterized by including:

The electrode body includes a plurality of first pole pieces and a plurality of second pole pieces. The second pole pieces are opposite in polarity to the first pole pieces. The plurality of first pole pieces and the plurality of second pole pieces are The pole pieces are alternately stacked, the first pole piece includes a first current collector and a first coating, the first current collector includes a first empty foil area and a first air foil area arranged along the extending direction of the first current collector. a coating area, the first coating area is coated with the first coating;

A first pole tab is welded to the first empty foil areas of the plurality of first pole pieces.
The electrode assembly according to claim 1, wherein the second pole piece includes a second current collector and a second coating, and the second current collector includes electrodes arranged along the extending direction of the second current collector. a second empty foil area and a second coating area, the second coating area being coated with the second coating;

Wherein, the electrode assembly further includes a second pole tab, and the second pole tab is welded to the second empty foil areas of the plurality of second pole pieces.
The electrode assembly according to claim 2, characterized in that:

In the height direction of the electrode body, the first pole tab and the second pole tab are located on the same side of the electrode body, and the height direction of the electrode body is in the same direction as the first pole piece and the third pole piece. The alternating stacking directions of the diode sheets intersect.
The electrode assembly according to claim 3, characterized in that, in the width direction of the electrode body, the distance d between the first tab and the second tab is d≥5mm, and the electrode The width direction of the body intersects the height direction of the electrode body.
The electrode assembly according to claim 3 or 4, characterized in that,

A plurality of the first pole pieces and a plurality of the second pole pieces are wound to form the electrode body, and one of the first pole tabs and the second pole tabs is located inside the electrode body. , the other is located outside the electrode body;

or,

A plurality of first pole pieces and a plurality of second pole piece laminations form the electrode body. In the length direction of the electrode body, the first pole tabs and the second pole tabs are arranged on On both sides of the electrode body, the length direction of the electrode body is perpendicular to the height direction of the electrode body and the stacking direction of the first pole piece and the second pole piece.
The electrode assembly according to claim 2, wherein in the height direction of the electrode body, the first tab and the second tab are located on both sides of the electrode body, and the electrode body The height direction intersects with the stacking direction of the first pole piece and the second pole piece.
The electrode assembly according to claim 6, wherein the extension dimension of the first empty foil area in the height direction of the electrode body is smaller than the first coating area; and/or, the second empty foil area The extension size of the area in the height direction of the electrode body is smaller than the second coating area; and/or the first empty foil area and the second empty foil area are spaced apart in the height direction of the electrode body. .
The electrode assembly according to claim 6, characterized in that:

A plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a winding structure, and the first pole tab and the second pole tab are located inside the winding structure or the first pole piece. The pole tab and the second pole tab are located outside the winding structure;

or,

A plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a laminate structure. In the length direction of the electrode body, the first pole tabs and the second pole tabs are located on the On the same side of the electrode body, the length direction of the electrode body intersects with the height direction of the electrode body.
The electrode assembly according to any one of claims 6 or 7, characterized in that,

A plurality of the first pole pieces and a plurality of the second pole pieces are alternately stacked to form a winding structure, and one of the first pole tabs and the second pole tabs is located inside the winding structure. , the other is located outside the coiled structure;

or,

A plurality of first pole pieces and a plurality of second pole pieces are alternately stacked to form a laminate structure. In the length direction of the electrode body, the first pole tabs and the second pole tabs are located on the On both sides of the electrode body, the length direction of the electrode body and the height direction of the electrode body intersect.
The electrode assembly according to any one of claims 2 to 9, characterized in that,

In the arrangement direction of the first empty foil area and the first coating area, the length of the first empty foil area is h1, where 3mm≤h1≤10mm;

and / or,

In the arrangement direction of the second empty foil area and the second coating area, the length of the second empty foil area is h2, where 3mm≤h2≤10mm.
The electrode assembly according to any one of claims 1 to 10, wherein the number of first pole pieces is n1,2≤n1≤10.
The electrode assembly according to claim 1, wherein the first current collector is a composite foil material in which a metal layer, a non-metal layer, and a metal layer are sequentially stacked along its thickness direction;

Wherein, in the thickness direction of the composite foil, the first empty foil areas are respectively formed on both sides of the composite foil, and additional foils are welded to each of the first empty foil areas, and are located at the The additional foils on both sides in the thickness direction of the composite foil are electrically connected to each other, and at least one of the additional foils on both sides in the thickness direction of the composite foil is welded to the first tab.
The electrode assembly according to claim 12, wherein in the thickness direction of the composite foil, the additional foil located on one side of the thickness of the composite foil is a first additional foil, and the additional foil located on the thickness side of the composite foil is a first additional foil. The additional foil on the other side of the foil is a second additional foil;

Wherein, the first additional foil material includes a first extended end extending from the composite foil material, the second additional foil material includes a second extended end extending from the composite foil material, and the first additional foil material includes a second extended end extending from the composite foil material. The length of the extension end protruding from the composite foil is greater than the length of the second extension end protruding from the composite foil, so as to form a welding portion for welding the first tab.
The electrode assembly according to any one of claims 1 to 13, wherein in a direction perpendicular to the arrangement direction of the first empty foil area and the first coating area, the first empty foil The width of the area is D1, the width of the first coating area is D, 0<D1≤D/2, and the width of the first empty foil area is the same as the second empty foil area.
A preparation method for preparing the electrode assembly according to any one of claims 1 to 14, characterized in that it includes:

Let a plurality of the first pole pieces and a plurality of the second pole pieces be alternately stacked;

Welding the first tab and the plurality of first empty foil areas;

The first pole piece and the second pole piece are pressed together to form the electrode body.
16. The preparation method according to claim 15, wherein the step of arranging a plurality of first pole pieces and a plurality of second pole pieces in alternating stacks includes: The empty foil area and the second empty foil area are located on the same side of the first pole piece in the arrangement direction of the first empty foil area and the first coating area. 17. The preparation method according to claim 14, wherein the step of arranging a plurality of first pole pieces and a plurality of second pole pieces in alternating stacks includes: The empty foil area and the second empty foil area are located on both sides of the first pole piece in the arrangement direction of the first empty foil area and the first coating area. 18. The preparation method according to any one of claims 15 to 17, characterized in that, before the step of pressing the first pole piece and the second pole piece to form the electrode body, it includes: rolling Around the first pole piece and the second pole piece O19, a battery cell is characterized by comprising the electrode assembly according to any one of claims 1 to 14. 20. A battery, comprising the battery cell according to claim 19. 21. An electrical device, characterized in that the electrical device includes the battery cell as claimed in claim 19, and the battery cell is used to provide electrical energy.