Battery cell and manufacturing method, battery, and power-using device

Abstract

The present application relates to a battery cell and a manufacturing method, a battery, and an electrical device. The battery cell includes an electrode assembly, and the electrode assembly includes a positive electrode sheet and a negative electrode sheet. The positive electrode sheet and / or the negative electrode sheet include a main body and a pole ear portion, and the pole ear portion has a weld print area; the pole sheet also includes an adhesive layer covering the weld print area, and the adhesive layer includes a base film and a glue layer; in the width direction of the pole sheet, the adhesive layer has an end close to the main body, and the end is aligned with the same side of the pole ear portion; and / or, the adhesive layer is constructed as a first insulating layer, the main body includes a bottom layer, an active material layer, and a second insulating layer, in the width direction of the pole sheet, one end of the second insulating layer is connected to the active material layer, and the other end is spaced from the pole ear portion; the adhesive layer simultaneously covers the weld print area and at least part of the second insulating layer. The adhesive layer of the present application can cover the particles of the pole ear portion on the one hand, and can reduce the probability of overlap between the positive electrode sheet and the negative electrode sheet on the other hand.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to battery cells and manufacturing methods, batteries and electrical devices. Background Art

[0002] The electrode assembly is usually formed by stacking a positive electrode sheet, a separator and a negative electrode sheet. During the stacking process, due to position deviation or size deviation of the positive and negative electrode sheets, the positive and negative electrode sheets may overlap easily, causing a short circuit in the electrode assembly. Summary of the invention

[0003] Based on this, it is necessary to provide a battery cell and a manufacturing method, a battery and an electrical device to address the problem of short circuit in the electrode assembly caused by overlapping the positive electrode sheet and the negative electrode sheet.

[0004] In the first aspect, the present application provides a battery cell, including an electrode assembly, the electrode assembly including a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet including a main body and a pole ear portion arranged on at least one side of the main body along the width direction of the pole sheet, the pole ear portion having a weld mark area, the weld mark area being arranged on one side of the pole ear portion close to the main body; the pole sheet also includes a bonding layer, the bonding layer covers the weld mark area, and the bonding layer includes a base film and a glue layer coated on the surface of the base film. In the width direction of the pole piece, the bonding layer has an end portion close to the main body, and the end portion is aligned with the same side of the pole ear portion; and / or the bonding layer is constructed as a first insulating layer and simultaneously covers the weld print area and part of the main body; wherein the main body includes a bottom layer and an active material layer stacked on the bottom layer along the thickness direction of the pole piece, the bottom layer includes a coating area and an uncoated area, the active material layer is located in the coating area, the uncoated area is located between the active material layer and the pole ear portion, and the bonding layer simultaneously covers the weld print area and the uncoated area; the main body also includes a second insulating layer arranged in the uncoated area, in the width direction of the pole piece, one end of the second insulating layer is connected to the active material layer, and the other end is spaced from the pole ear portion; the bonding layer simultaneously covers the weld print area and at least part of the second insulating layer.

[0005] Through the above structure, on the one hand, the bonding layer can cover the particles generated during the welding process of the pole ear, reducing the risk of the diaphragm being punctured; on the other hand, the bonding layer can also form a partition between the positive electrode sheet and the negative electrode sheet, reducing the probability of overlap between the positive electrode sheet and the negative electrode sheet, and effectively improving the short circuit problem of the electrode assembly.

[0006] Furthermore, a physical isolation layer is formed by the base film, which can not only better cover the particles in the weld print area, but also effectively improve the overlap problem between the positive electrode sheet and the negative electrode sheet, and reduce the probability of short circuit in the electrode assembly.

[0007] Through the above structure, the adhesive layer can better cover the weld print area, thereby improving the coverage effect of the adhesive layer on the weld print area and further reducing the probability of overlap between the positive electrode sheet and the negative electrode sheet.

[0008] Through the above structure, on the one hand, the adhesive layer can not only better cover the weld area and part of the main body, further reducing the probability of overlap between the positive electrode sheet and the negative electrode sheet. On the other hand, the adhesive layer can form a connection and support between the ear part and the main body, improve the strength of this part of the area, and reduce the probability of wrinkles.

[0009] Furthermore, the adhesive layer can play a connecting and supporting role between the weld print area and the second insulating layer, thereby improving the structural strength of a section of the bottom layer between the second insulating layer and the weld print area and reducing the probability of wrinkles.

[0010] In this way, the bonding layer can not only play a separating role, but also connect and support the weld print area and the uncoated area, thereby improving the structural strength of the uncoated area.

[0011] In some embodiments, the adhesive layer covers the weld print area, the second insulating layer and a portion of the active material layer at the same time.

[0012] Through the above structure, the adhesive layer can further improve the connection and support between the weld print area, the second insulating layer and the active material layer, so that the structural strength of the interval between the second insulating layer and the weld print area is higher.

[0013] In some embodiments, in the width direction of the electrode piece, the width of the adhesive layer covering the active material layer ranges from 0 to 3 mm.

[0014] Through the above structure, the bonding layer can not only form a connection and support between the weld print area and the active material layer, thereby improving the structural strength of the interval between the second insulating layer and the weld print area, but also the edge of the bonding layer located on the active material layer is not prone to bulging, making the structure of the bonding layer more solid.

[0015] In some embodiments, in the width direction of the pole piece, the width of the adhesive layer ranges from 1 mm to 15 mm.

[0016] In some embodiments, in the width direction of the pole piece, the width of the adhesive layer ranges from 2 mm to 11 mm.

[0017] The width of the bonding layer is set within the above range, so that the bonding layer can better cover the weld print area and the second insulating layer under the premise of less impact on the capacity of the electrode assembly, thereby reducing the probability of overlap between the positive and negative electrode sheets after stacking, and improving the structural strength of the spacing between the weld print area and the second insulating layer, thereby reducing the probability of cracks after folding the electrode ears.

[0018] In some embodiments, in the width direction of the pole piece, the spacing distance between the weld print area and the second insulating layer is 0 mm to 1 mm.

[0019] Setting the spacing distance between the weld print area and the second insulating layer within the above range and then covering the weld print area and the second insulating layer with the adhesive layer at the same time can effectively improve the supporting strength between the weld print area and the second insulating layer and reduce the probability of creases and cracks between the weld print area and the second insulating layer.

[0020] In some embodiments, in the thickness direction of the pole piece, the total thickness of the adhesive layer is not greater than the thickness of the main body.

[0021] Therefore, by setting the total thickness of the adhesive layer to be no greater than the thickness of the main body, it is possible to achieve smooth coverage of the weld print area and part of the main body without affecting the subsequent stacking of the positive and negative electrode sheets.

[0022] In a second aspect, the present application also provides a battery, comprising the battery cell as described above.

[0023] In a third aspect, the present application also provides an electrical device, comprising the battery as described above.

[0024] In a fourth aspect, the present application further provides a method for manufacturing a battery cell, wherein the battery cell comprises an electrode assembly, the electrode assembly comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet comprises a main body and a pole ear portion arranged on at least one side of the main body along the width direction of the pole sheet, the pole ear portion has a weld print area, and the weld print area is arranged on a side of the pole ear portion close to the main body; the main body comprises a bottom layer and an active material layer stacked on the bottom layer along the thickness direction of the pole sheet; the bottom layer comprises a coating area and an uncoated area, the active material layer is located in the coating area, and the uncoated area is located between the active material layer and the pole ear portion; the main body further comprises a second insulating layer arranged in the uncoated area, and in the width direction of the pole sheet, one end of the second insulating layer is connected to the active material layer, and the other end is spaced from the pole ear portion;

[0025] The preparation method comprises the following steps:

[0026] Die cutting: die cutting the raw materials to form pole pieces;

[0027] Positioning, identifying the edge of the active material layer close to the pole ear and setting it as the reference edge;

[0028] Gluing, covering the welding area with an adhesive layer according to the position of the reference edge; wherein the adhesive layer includes a base film and an adhesive layer coated on the surface of the base film; specifically, calculating the position of the edge of the pole ear portion close to the reference edge according to the position of the reference edge, covering the welding area with the adhesive layer, and aligning the end of the adhesive layer with the edge of the pole ear portion close to the reference edge; and / or, covering the welding area and at least part of the second insulating layer with the adhesive layer according to the position of the reference edge;

[0029] Inspection: inspect the position and size of the bonding layer in the weld print area, and inspect the appearance defects of the bonding layer.

[0030] Thus, the raw material can be die-cut to form the pole piece first, and then each pole piece can be glued more accurately, so that the tape can better cover the weld print area. In addition, the positioning and detection process can further improve the glue sticking accuracy and glue sticking quality.

[0031] Furthermore, the adhesive layer can better cover the weld mark area, effectively conceal the metal particles in the weld mark area, and play a good separation role when the positive electrode sheet and the negative electrode sheet are stacked, reducing the probability of overlapping short circuits between the positive electrode sheet and the negative electrode sheet.

[0032] Therefore, the adhesive layer can not only cover the weld print area, but also provide a supporting force between the weld print area and the main body, thereby improving the structural strength between the weld print area and the main body and reducing the probability of creases or cracks.

[0033] The adhesive layer can improve the structural strength between the weld print area and the second insulating layer and reduce the probability of creases or cracks.

[0034] In some embodiments, the gluing step specifically includes:

[0035] According to the position of the reference edge, the bonding layer is simultaneously covered on the weld print area, the second insulating layer and part of the active material layer; wherein, in the width direction of the electrode sheet, the width range of the bonding layer covering the active material layer is 0-3 mm.

[0036] In this way, the bonding layer can not only form a connection and support between the weld print area and the active material layer, thereby improving the structural strength of the uncoated area, but also the edge of the bonding layer on the active material layer is not prone to bulging, making the structure of the bonding layer more solid.

[0037] In some embodiments, before the die-cutting step, the method further comprises the following steps:

[0038] Welding, identify the edge of one side of the second insulating layer close to the pole ear as a reference edge, weld the pole ear according to the position of the reference edge and form a weld mark area; wherein, in the width direction of the pole piece, the spacing distance between the weld mark area and the reference edge is controlled to be 0mm~1mm.

[0039] Therefore, the supporting strength between the weld print area and the second insulating layer can be effectively improved, and the probability of creases and cracks between the weld print area and the second insulating layer can be reduced.

[0040] The above-mentioned battery cell and manufacturing method, battery and electrical device, the electrode sheet can be divided into a main body and a pole ear portion, the main body is coated with active material, and the main bodies of the positive electrode sheet and the negative electrode sheet are separated by a diaphragm, and the pole ear portion is used to connect with a adapter or other structure to facilitate the input and output of electricity; an adhesive layer is provided to cover the pole ear portion. On the one hand, the adhesive layer can cover the particles generated during the welding process of the pole ear portion, and on the other hand, it can form a partition between the positive electrode sheet and the negative electrode sheet, reduce the probability of overlap between the positive electrode sheet and the negative electrode sheet, and effectively improve the short circuit problem of the electrode assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of the structure of a vehicle according to one or more embodiments.

[0042] Figure 2 is a schematic diagram of an exploded structure of a battery according to one or more embodiments.

[0043] Figure 3 is a schematic diagram of an exploded structure of a battery cell according to one or more embodiments.

[0044] Figure 4 Schematic diagram of the structure of a pole piece according to one or more embodiments.

[0045] Figure 5 Schematic diagram of the structure of a pole piece according to one or more embodiments.

[0046] Figure 6 Schematic diagram of the structure of a pole piece according to one or more embodiments.

[0047] Figure 7 Schematic diagram of the structure of a pole piece according to one or more embodiments.

[0048] Figure 8 Schematic diagram of the structure of a pole piece according to one or more embodiments.

[0049] Fig. 9 The figure is a schematic flow chart of a method for manufacturing a battery cell according to one or more embodiments.

[0050] Explanation of the reference numerals: 1000, vehicle; 100, battery; 200, controller; 300, motor; 10, housing; 20, battery cell; 11, first part; 12, second part; 21, end cap; 22, shell; 23, electrode assembly; 24, pole piece; 241, main body; 242, pole ear; 243, weld stamp area; 244, adhesive layer; 245, end; 246, second insulating layer; 21a, electrode terminal; 2411, bottom layer; 2412, active material layer; 2413, coating area; 2414, uncoated area; 2411a, polymer layer; 2411b, metal layer; a, width direction; b, thickness direction. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0052] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0053] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0054] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0055] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0056] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0057] At present, from the perspective of market development, 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 also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0058] A battery cell is the smallest unit that makes up a battery, and in the structure of a battery cell, the electrode assembly is the main component where electrochemical reactions occur. The electrode assembly is mainly formed by stacking a positive electrode sheet, a separator, and a negative electrode sheet in sequence. For both the positive electrode sheet and the negative electrode sheet, they include a main body and a lug. The part with active material on the positive electrode sheet or the negative electrode sheet forms the main body, and the part without active material forms the lug. The lug can be arranged on one side or two opposite sides of the main body along the width direction of the electrode sheet.

[0059] During the stacking process, the diaphragm is sandwiched between the main body of the positive electrode sheet and the negative electrode sheet to separate the main body of the positive and negative electrode sheets, while the ear portion is used to connect with the adapter or other structure to form a current loop, thereby realizing the input and output of electricity of the battery cell.

[0060] For the current structure of battery cells, in order to improve the puncture resistance and impact resistance of battery cells, the current collector is usually set as a composite current collector, which may include a polymer layer and metal layers arranged on the upper and lower sides of the polymer layer. Among them, the area coated with active material on the composite current collector forms the main body, and the area not coated with active material forms the pole ear.

[0061] Based on this, during the stacking process of the positive and negative electrodes, the stacking positions of the positive and negative electrodes may deviate, and the sizes of the positive and negative electrodes may also deviate. At this time, the above deviations may easily lead to overlaps at the ear portions of the positive and negative electrodes when the positive and negative electrodes are stacked, thereby causing a short circuit in the electrode assembly.

[0062] Based on the above considerations, in order to solve the problem of short circuit of the electrode assembly caused by overlapping of the positive electrode sheet and the negative electrode sheet, one or more embodiments of the present application provide a pole sheet, and a bonding layer is provided on the pole ear portion. On the one hand, the bonding layer can cover the particles generated during the welding process of the pole ear portion, and on the other hand, it can form a partition between the positive electrode sheet and the negative electrode sheet, thereby reducing the probability of overlapping of the positive electrode sheet and the negative electrode sheet, and effectively improving the short circuit problem of the electrode assembly.

[0063] The battery cells disclosed in one or more embodiments of the present application may be used, but not limited to, in electrical devices such as vehicles, ships, or aircraft. The embodiments of the present application provide an electrical device using a battery as a power source, and the electrical device may be, but not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy may include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, an electric airplane toy, and the like, and the spacecraft may include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0064] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0065] Please refer to Figure 1The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000. The battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to power the motor 300, for example, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0066] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0067] Please refer to Figure 2 The battery 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is accommodated in the box body 10. The box body 10 is used to provide a storage space for the battery cell 20, and the box body 10 can adopt a variety of structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, and the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space for accommodating the battery cell 20. The second part 12 may be a hollow structure with one end open, and the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can be a variety of shapes, such as a cylinder, a cuboid, etc.

[0068] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. The multiple battery cells 20 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box 10; of course, the battery 100 may also be a battery module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 10. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 20.

[0069] Each battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0070] Please refer to Figure 3 The battery cell 20 refers to the smallest unit constituting the battery, and the battery cell 20 includes an end cover 21, a shell 22, an electrode assembly 23 and other functional components.

[0071] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals 21a can be provided on the end cap 21. The electrode terminal 21a can be used to electrically connect with the electrode assembly 23 for outputting or inputting electrical energy of the battery cell 20. In some embodiments, the end cap 21 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap 21 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose special restrictions on this. In some embodiments, an insulating member may be provided inside the end cap 21, and the insulating member may be used to isolate the electrical connection components in the housing 22 from the end cap 21 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0072] The shell 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 23, the electrolyte and other components. The shell 22 and the end cap 21 can be independent components, and an opening can be set on the shell 22, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap 21 at the opening. Without limitation, the end cap 21 and the shell 22 can also be integrated. Specifically, the end cap 21 and the shell 22 can form a common connection surface before other components are put into the shell, and when the interior of the shell 22 needs to be encapsulated, the end cap 21 covers the shell 22. The shell 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the shell 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0073] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. The housing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly, and the parts of the positive and negative electrode sheets without active materials each constitute the pole ear parts, which may be located together at one end of the main body or at both ends of the main body.

[0074] See also Figure 4 , an embodiment of the present application provides a battery cell 20, the battery cell 20 includes an electrode assembly 23, and the electrode assembly 23 includes a positive electrode sheet and a negative electrode sheet. Among them, the positive electrode sheet and / or the negative electrode sheet (collectively referred to as the electrode sheet 24) includes a main body 241 and a pole ear portion 242 arranged on at least one side of the main body 241 along the width direction a of the electrode sheet 24. The pole ear portion 242 has a weld mark area 243, and the weld mark area 243 is arranged on one side of the pole ear portion 242 close to the main body 241. The pole sheet 24 also includes a bonding layer 244, the bonding layer 244 covers the welding mark area 243, and the bonding layer 244 includes a base film (not shown in the figure) and a glue layer (not shown in the figure) coated on the surface of the base film.

[0075] It should be noted that the pole piece 24 includes a positive pole piece and a negative pole piece. The pole piece 24 is usually formed by coating an active material on a current collector. The positive pole piece is formed by coating a positive active material on a current collector, while the negative pole piece is formed by coating a negative active material on a current collector. The portion of the positive pole piece and the negative pole piece having the active material is the main body 241, and the portion without the active material is the pole ear portion 242.

[0076] The pole ear portion 242 may be disposed on one side or two opposite sides of the main body portion 241 along the width direction a of the pole piece 24 . The specific arrangement may be adjusted according to the type of battery cell 20 to be ultimately formed, which will not be elaborated herein.

[0077] When the pole piece 24 is manufactured, it is a coiled material structure formed by winding, and the width direction a of the pole piece 24 refers to the radial direction of the coiled material structure.

[0078] Furthermore, the pole ear portion 242 has a weld print area 243 , which is disposed on one side of the pole ear portion 242 close to the main body portion 241 , and the adhesive layer 244 covers the weld print area 243 .

[0079] It should be noted that the current collector can be a single current collector or a composite current collector. In the single current collector structure, the pole ear portion 242 does not need to be welded, and the bonding layer 244 only needs to cover the edge of one side where the pole ear portion 242 and the main body portion 241 are connected.

[0080] For the current pole piece 24, in order to improve the puncture resistance and impact resistance of the battery cell 20, the current collector is usually set as a composite current collector. Therefore, in order to improve the connection stability between the pole ear portion 242 and the main body portion 241, it is necessary to weld the pole ear portion 242 to form a weld mark area 243. Specifically, at present, the pole piece 24 of the coil structure is usually welded by rolling welding, and the weld mark area 243 is set close to the main body portion 241, and then the coil structure is die-cut to form the pole piece 24.

[0081] Furthermore, metal particles are formed during the welding process, and some of the metal particles remain in the weld mark area 243. These metal particles form protrusions in the weld mark area 243, which increases the risk of the diaphragm being punctured. In addition, when the positive and negative electrode sheets are stacked, there may be position deviations and size deviations, which may cause the positive and negative electrode sheets to overlap, thereby causing the electrode assembly 23 to short-circuit.

[0082] Based on this, the present application covers the welding area 243 with an adhesive layer 244. On the one hand, the adhesive layer 244 can cover the particles generated during the welding process of the welding area 243, thereby reducing the risk of the diaphragm being punctured; on the other hand, the adhesive layer 244 can also form a partition between the positive electrode sheet and the negative electrode sheet, thereby reducing the probability of overlapping of the positive electrode sheet and the negative electrode sheet, and effectively improving the short circuit problem of the electrode assembly 23.

[0083] In some embodiments, the adhesive layer 244 includes a base film and an adhesive layer coated on the surface of the base film.

[0084] Specifically, the adhesive layer 244 can be configured as an adhesive tape, and the adhesive tape includes a base film and an adhesive layer coated on one surface of the base film.

[0085] Since the metal particles generated during welding form protrusions in the weld print area 243, the surface of the weld print area 243 is uneven. If glue is applied to cover the weld print area 243, on the one hand, the glue coating thickness cannot be uniform, which may cause leakage in some areas and cause overlap between the positive and negative electrodes. On the other hand, the glue cannot cover the metal particles well, and some larger metal particles may not be covered, and there is still a risk of puncturing the diaphragm.

[0086] Based on this, a physical isolation layer is formed by the base film, which can not only better cover the particles in the weld print area 243, but also effectively improve the overlap problem between the positive electrode sheet and the negative electrode sheet, and reduce the probability of short circuit in the electrode assembly 23.

[0087] It should be noted that, in addition to the structure of the base film and the adhesive layer, the bonding layer 244 may also include an inorganic layer or other layer structures, which may be specifically adjusted according to actual conditions and will not be elaborated herein.

[0088] In some embodiments, in the width direction a of the pole piece 24 , the adhesive layer 244 has an end portion 245 close to the main body portion 241 , and the end portion 245 is aligned with the same side of the pole ear portion 242 .

[0089] Specifically, the end 245 of the adhesive layer 244 is arranged toward the main body 241 along the width direction a of the pole piece 24. In the process of applying the tape, the tape covers the weld print area 243, and the end 245 of the tape facing the main body 241 is aligned with the end 245 of the pole ear 242 facing the main body 241, that is, the side surface of the tape facing the main body 241 and the side surface of the pole ear 242 facing the main body 241 are located in the same plane.

[0090] Through the above structure, the adhesive layer 244 can better cover the weld print area 243, thereby improving the covering effect of the adhesive layer 244 on the weld print area 243 and further reducing the probability of overlap between the positive electrode sheet and the negative electrode sheet.

[0091] like Figure 5 As shown, in some embodiments, the weld print area 243 is disposed on the side where the ear portion 242 is connected to the main body portion 241 , and the adhesive layer 244 is constructed as a first insulating layer and covers the weld print area 243 and a portion of the main body portion 241 at the same time.

[0092] Specifically, the first insulating layer refers to the adhesive layer 244 being made of insulating material, so that the adhesive layer 244 can have insulating properties.

[0093] It should be noted that since the weld mark area 243 has a higher structural strength after welding, the position of the main body 241 close to the weld mark area 243 is weaker than the weld mark area 243, and wrinkles are prone to appear in this area. When the electrode assembly 23 is put into the shell, a crease will be formed between the ear portion 242 and the main body 241 when the ear is folded, so that cracks are prone to appear at the wrinkle position.

[0094] Based on this, the bonding layer 244 is extended to one side of the main body 241, and the bonding layer 244 can simultaneously cover the weld print area 243 and part of the main body 241. On the one hand, the bonding layer 244 can not only better cover the weld print area 243 and part of the main body 241, but also further reduce the probability of overlap between the positive electrode sheet and the negative electrode sheet. On the other hand, the bonding layer 244 can form a connection and support between the ear portion 242 and the main body 241, thereby improving the strength of this area and reducing the probability of wrinkles.

[0095] In some embodiments, the main body 241 includes a bottom layer 2411 and an active material layer 2412 stacked on the bottom layer 2411 along the thickness direction b of the pole piece 24, the bottom layer 2411 includes a coating area 2413 and an uncoated area 2414, the active material layer 2412 is located in the coating area 2413, and the uncoated area 2414 is located between the active material layer 2412 and the pole ear portion 242. The adhesive layer 244 covers both the weld print area 243 and the uncoated area 2414.

[0096] Specifically, the bottom layer 2411 can be set as a composite current collector, and includes a polymer layer 2411a and a metal layer 2411b disposed on the upper and lower sides of the polymer layer 2411a. The active material layer 2412 is disposed on the metal layer 2411b along the thickness direction b of the pole piece 24, wherein the active material layer 2412 is usually disposed on opposite sides, that is, the metal layers 2411b are respectively disposed on the opposite two side surfaces of the polymer layer 2411a, and an active material layer 2412 is disposed on the side surface of each metal layer 2411b away from the polymer layer 2411a.

[0097] The active material layer 2412 can be configured as a first active material layer and a second active material layer according to actual requirements of the electrode 24 , and the first active material layer and the second active material layer are sequentially stacked on the metal layer 2411 b .

[0098] Furthermore, the bottom layer 2411 can be divided into a coated area 2413 and an uncoated area 2414 , wherein the active material layer 2412 is arranged in the coated area 2413 , and the uncoated area 2414 is located between the active material layer 2412 and the pole ear portion 242 , that is, the active material layer 2412 and the pole ear portion 242 are arranged at intervals.

[0099] In the above structure, the uncoated area 2414 between the active material layer 2412 and the pole ear portion 242 is relatively weak compared to the active material layer 2412 and the pole ear portion 242 , so the uncoated area 2414 is prone to wrinkles, and thus cracks are prone to occur during the process of folding the pole ear.

[0100] Therefore, the adhesive layer 244 covers both the weld print area 243 and the uncoated area 2414. In this way, the adhesive layer 244 can not only separate the weld print area 243 and the uncoated area 2414, but also connect and support the weld print area 243 and the uncoated area 2414, thereby improving the structural strength of the uncoated area 2414.

[0101] like Figure 6 As shown, in some embodiments, the adhesive layer 244 covers the weld print area 243 , the uncoated area 2414 and a portion of the active material layer 2412 at the same time.

[0102] Furthermore, the adhesive layer 244 is further extended toward the side of the active material layer 2412, and the adhesive layer 244 covers the weld imprint area 243, the uncoated area 2414, and part of the active material layer 2412. In this way, the adhesive layer 244 can further improve the connection and support between the weld imprint area 243, the uncoated area 2414, and the active material layer 2412, so that the structural strength of the uncoated area 2414 is higher.

[0103] In some embodiments, in the width direction a of the electrode piece 24 , the width of the adhesive layer 244 covering the active material layer 2412 is in the range of 0 to 3 mm.

[0104] As a specific embodiment, the width of the adhesive layer 244 covering the active material layer 2412 can be set to 2 mm.

[0105] Through the above structure, the bonding layer 244 can not only form a connection and support between the weld print area 243 and the active material layer 2412, thereby improving the structural strength of the uncoated area 2414, but also the edge of the bonding layer 244 located on the active material layer 2412 is not prone to bulging, thereby making the structure of the bonding layer 244 more solid.

[0106] like Figure 7 As shown, in some embodiments, the main body 241 further includes a second insulating layer 246 disposed in the uncoated area 2414. In the width direction a of the pole piece 24, one end of the second insulating layer 246 is connected to the active material layer 2412, and the other end is spaced apart from the pole ear portion 242. The adhesive layer 244 covers the welded area 243 and at least a portion of the second insulating layer 246 at the same time.

[0107] Specifically, the second insulating layer 246 refers to a metal layer 2411b connected to one side of the active material layer 2412 close to the pole ear portion 242 and covering a portion of the uncoated area 2414 so as to better isolate the metal layer 2411b between the positive electrode sheet and the negative electrode sheet.

[0108] In the width direction a of the electrode piece 24, one end of the second insulating layer 246 is connected to the active material layer 2412, and the other end is spaced apart from the electrode ear portion 242. Therefore, a section of the bottom layer 2411 between the second insulating layer 246 and the weld print area 243 is relatively weak and prone to wrinkles, which leads to cracks after the electrode ear is folded.

[0109] Therefore, the adhesive layer 244 covers the weld print area 243 and at least part of the second insulating layer 246 at the same time, that is, one end of the adhesive layer 244 adheres to the weld print area 243, and the other end spans a section of the bottom layer 2411 between the second insulating layer 246 and the weld print area 243 and adheres to the second insulating layer 246.

[0110] In this way, the adhesive layer 244 can play a connecting and supporting role between the weld print area 243 and the second insulating layer 246, thereby improving the structural strength of a section of the bottom layer 2411 between the second insulating layer 246 and the weld print area 243 and reducing the probability of wrinkles.

[0111] like Figure 8 As shown, in some embodiments, the adhesive layer 244 covers the weld print area 243 , the second insulating layer 246 and a portion of the active material layer 2412 at the same time.

[0112] Furthermore, the adhesive layer 244 can continue to extend toward the side of the active material layer 2412, and the adhesive layer 244 can simultaneously cover the weld print area 243, the second insulating layer 246, and a portion of the active material layer 2412. In this way, the adhesive layer 244 can further improve the connection and support between the weld print area 243, the second insulating layer 246, and the active material layer 2412, so that the structural strength of the interval between the second insulating layer 246 and the weld print area 243 is higher.

[0113] In some embodiments, in the width direction a of the electrode piece 24 , the width of the adhesive layer 244 covering the active material layer 2412 is in the range of 0 to 3 mm.

[0114] As a specific embodiment, the width of the adhesive layer 244 covering the active material layer 2412 can be set to 2 mm.

[0115] Through the above structure, the bonding layer 244 can not only form a connection and support between the weld print area 243 and the active material layer 2412, thereby improving the structural strength of the interval between the second insulating layer 246 and the weld print area 243, but also the edge of the bonding layer 244 located on the active material layer 2412 is not prone to bulging, making the structure of the bonding layer 244 more solid.

[0116] In some embodiments, in the width direction a of the pole piece 24 , the width of the adhesive layer 244 ranges from 1 mm to 15 mm.

[0117] Specifically, the width of the adhesive layer 244 not only affects the probability of overlap between the positive and negative electrodes, but also affects the capacity of the electrode assembly 23. In addition, the width of the adhesive layer 244 also affects the structural strength of the interval between the weld print area 243 and the second insulating layer 246.

[0118] Based on this, the width of the bonding layer 244 is set to the above range, so that the bonding layer 244 can better cover the weld area 243 and the second insulating layer 246 under the premise of less impact on the capacity of the electrode assembly 23, thereby reducing the probability of overlap between the positive and negative electrode sheets after stacking, and improving the structural strength of the spacing between the weld area 243 and the second insulating layer 246, thereby reducing the probability of cracks after folding the electrode ears.

[0119] As a preferred embodiment, in the width direction a of the pole piece 24 , the width of the adhesive layer 244 ranges from 2 mm to 11 mm.

[0120] In the above range, the adhesive layer 244 can further enhance the supporting effect between the weld print area 243 and the second insulating layer 246 .

[0121] In some embodiments, in the width direction a of the pole piece 24 , the spacing distance between the weld print area 243 and the second insulating layer 246 is 0 mm to 1 mm.

[0122] Specifically, before providing the adhesive layer 244, the spacing distance between the weld print area 243 and the second insulating layer 246 can be adjusted. The spacing distance between the weld print area 243 and the second insulating layer 246 is set within the above range, and then the adhesive layer 244 is simultaneously covered on the weld print area 243 and the second insulating layer 246, which can effectively improve the support strength between the weld print area 243 and the second insulating layer 246, and reduce the probability of creases and cracks between the weld print area 243 and the second insulating layer 246.

[0123] In some embodiments, in the thickness direction b of the pole piece 24 , the total thickness of the adhesive layer 244 is not greater than the thickness of the main body 241 .

[0124] Specifically, when the adhesive layer 244 covers the weld print area 243 and / or the second insulating layer 246, the adhesive layer 244 actually includes two layers located on the opposite side surfaces of the weld print area 243 along the thickness direction b of the pole piece 24, that is, the adhesive layer 244 actually includes an upper and lower layer.

[0125] Therefore, the total thickness of the bonding layer 244 refers to the sum of the thicknesses of the two bonding layers 244 , and the thickness of the main body 241 refers to the sum of the thicknesses of the polymer layer 2411 a , the metal layer 2411 b , and the active material layer 2412 .

[0126] Therefore, the total thickness of the adhesive layer 244 is set to be no greater than the thickness of the main body 241 , which can achieve smooth coverage of the weld print area 243 and part of the main body 241 without affecting the subsequent stacking of the positive and negative electrode sheets.

[0127] Based on the same concept as the above-mentioned battery cell 20 , the present application also provides a battery 100 , including the above-mentioned battery cell 20 .

[0128] Based on the same concept as the above-mentioned battery 100 , the present application also provides an electrical device, including the above-mentioned battery 100 .

[0129] like Fig. 9 As shown, based on the same concept as the above-mentioned battery cell 20, the present application also provides a method for manufacturing a battery cell 20, the battery cell 20 includes an electrode assembly 23, the electrode assembly 23 includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet (collectively referred to as the electrode sheet 24) includes a main body 241 and a pole ear portion 242 arranged on at least one side of the main body 241 along the width direction a of the electrode sheet 24, the pole ear portion 242 has a weld mark area 243, and the weld mark area 243 is arranged on one side of the pole ear portion 242 close to the main body 241; the main body 241 includes a bottom layer 2411 and an active material layer 2412 stacked on the bottom layer 2411 along the thickness direction b of the electrode sheet 24.

[0130] The preparation method comprises the following steps:

[0131] S10: Die-cutting: die-cutting the raw material to form the pole piece 24.

[0132] It should be noted that the pole piece 24 is in the form of a coil when it is manufactured. The coil is the raw material. The raw material is die-cut according to actual production needs to form a pole piece 24 that meets the requirements. This is the die-cutting process of the pole piece 24 .

[0133] S20 : ​​Positioning: identifying the edge of the active material layer 2412 close to the electrode ear portion 242 and setting it as a reference edge.

[0134] Specifically, an inductive sensor or a visual camera may be used to detect and identify one side edge of the active material layer 2412 close to the pole ear portion 242 , and the edge may be set as a reference edge for use as a reference in the subsequent glue laminating process.

[0135] S30: Gluing: covering the adhesive layer 244 on the weld print area 243 according to the position of the reference edge; wherein the adhesive layer 244 includes a base film and an adhesive layer coated on the surface of the base film.

[0136] Furthermore, the pole ear portion 242 has a weld print area 243 , which is disposed on one side of the pole ear portion 242 close to the main body portion 241 , and the adhesive layer 244 covers the weld print area 243 .

[0137] Specifically, during the gluing process, the position of the reference edge can be determined first, and then the distance between the weld print area 243 and the reference edge can be detected or calculated, and then the adhesive tape can be accurately covered on the weld print area 243 by the gluing device to improve the gluing accuracy.

[0138] S40 : Detection: Detect the position and size of the adhesive layer 244 in the weld print area 243 , and detect appearance defects of the adhesive layer 244 .

[0139] After the glue is applied, the visual camera is used to further detect the specific position of the tape, the size of the tape, and the appearance defects on the tape, thereby further improving the glue application accuracy and quality.

[0140] It should be noted that, compared with coating water-based glue, the glue-sticking method allows the raw material to be die-cut first to form the pole piece 24 , and then glue is more accurately applied to each pole piece 24 , so that the tape can better cover the weld print area 243 .

[0141] In addition, the positioning and detection process can further improve the glue sticking accuracy and quality.

[0142] In some embodiments, step S30 specifically includes:

[0143] The position of one side edge of the pole ear 242 close to the reference edge is calculated according to the position of the reference edge, the adhesive layer 244 is covered on the weld print area 243, and the end 245 of the adhesive layer 244 is aligned with the one side edge of the pole ear 242 close to the reference edge.

[0144] Specifically, the adhesive layer 244 may only cover the weld print area 243. At this time, the position of the reference edge is first determined, and then the position of the edge of the pole ear portion 242 close to the reference edge is calculated, and in the process of covering the adhesive layer 244, the end 245 of the adhesive layer 244 is aligned with the edge of the pole ear portion 242 close to the reference edge.

[0145] Therefore, the adhesive layer 244 can better cover the weld mark area 243, effectively cover the metal particles in the weld mark area 243, and play a good separation role when the positive electrode sheet and the negative electrode sheet are stacked, reducing the probability of overlapping short circuits between the positive electrode sheet and the negative electrode sheet.

[0146] In some embodiments, step S30 specifically includes:

[0147] The adhesive layer 244 covers the weld print area 243 and a portion of the main body 241 at the same time according to the position of the reference edge.

[0148] Specifically, the adhesive layer 244 may also cover the weld print area 243 and part of the main body 241 at the same time. At this time, the position of the reference edge is first determined, and then the width of the adhesive layer 244 covering the main body 241 is obtained according to the actual size of the main body 241, and then the adhesive layer 244 is accurately covered on the weld print area 243 and the main body 241 according to the above parameters.

[0149] Therefore, the adhesive layer 244 can not only cover the weld print area 243, but also provide a supporting force between the weld print area 243 and the main body 241, thereby improving the structural strength between the weld print area 243 and the main body 241 and reducing the probability of creases or cracks.

[0150] In some embodiments, step S30 specifically includes:

[0151] The adhesive layer 244 covers the weld print area 243 and at least a portion of the second insulating layer 246 at the same time according to the position of the reference edge.

[0152] Specifically, when the uncoated area 2414 is provided with the second insulating layer 246, the adhesive layer 244 can be simultaneously covered on the weld print area 243 and at least a portion of the second insulating layer 246. At this time, the position of the reference edge is first determined, and then the position of the edge of the second insulating layer 246 facing the pole ear portion 242 is calculated, and then the adhesive layer 244 is covered on the weld print area 243 and the second insulating layer 246 according to the above parameters.

[0153] Therefore, the adhesive layer 244 can improve the structural strength between the weld print area 243 and the second insulating layer 246 and reduce the probability of creases or cracks.

[0154] In some embodiments, step S30 specifically includes:

[0155] The adhesive layer 244 covers the weld print area 243 , the second insulating layer 246 and part of the active material layer 2412 simultaneously according to the position of the reference edge; wherein, in the width direction a of the electrode 24 , the width range of the adhesive layer 244 covering the active material layer 2412 is 0 to 3 mm.

[0156] Specifically, the adhesive layer 244 can simultaneously cover the weld print area 243, the second insulating layer 246, and a portion of the active material layer 2412. At this time, the position of the reference edge is first determined, and then the width of the adhesive layer 244 covering the active material layer 2412 is determined according to the size of the active material layer 2412, and then the adhesive layer 244 is accurately covered on the weld print area 243, the second insulating layer 246, and the active material layer 2412 according to the above parameters.

[0157] The width of the adhesive layer 244 covering the active material layer 2412 is set to 0-3 mm. As a specific embodiment, the width of the adhesive layer 244 covering the active material layer 2412 can be set to 2 mm. In this way, the adhesive layer 244 can not only form a connection and support between the weld print area 243 and the active material layer 2412, and improve the structural strength of the uncoated area 2414, but also the edge of the adhesive layer 244 located on the active material layer 2412 is not prone to bulging, making the structure of the adhesive layer 244 more solid.

[0158] In some embodiments, before step S10, the step further includes:

[0159] S09: Welding, identifying the edge of one side of the second insulating layer 246 close to the pole ear 242 as a reference edge, welding the pole ear 242 according to the position of the reference edge and forming a weld mark area 243; wherein, in the width direction a of the pole piece 24, the spacing distance between the weld mark area 243 and the reference edge is controlled to be 0 mm~1 mm.

[0160] Specifically, before the die-cutting operation is performed, the pole piece 24 is in a coiled structure. At this time, the pole ear portion 242 can be welded by rolling welding to form a weld mark area 243 .

[0161] Before welding, a high-precision induction sensor is first used to detect and identify the edge of the second insulating layer 246 close to the pole ear 242 as a reference edge. The pole ear 242 is welded according to the position of the reference edge and the actual size of the pole ear 242 to form a weld mark area 243.

[0162] Among them, through the above-mentioned positioning method, the spacing distance between the weld print area 243 and the reference edge is controlled between 0mm and 1mm, which can effectively improve the supporting strength between the weld print area 243 and the second insulating layer 246 and reduce the probability of creases and cracks between the weld print area 243 and the second insulating layer 246.

[0163] It is understandable that after welding is completed, an inductive sensor or a visual camera may be used to detect the actual distance between the weld mark area 243 and the reference edge to further improve the positioning accuracy of the weld mark area 243 .

[0164] According to one or more embodiments, when the present application is used, a high-precision induction sensor is first used for detection to identify a side edge of the second insulating layer 246 close to the pole ear portion 242 and use it as a reference edge. According to the position of the reference edge and the actual size of the pole ear portion 242, the pole ear portion 242 is welded to form a weld mark area 243, and the interval between the weld mark area 243 and the reference edge is controlled to be between 0 mm and 1 mm.

[0165] Furthermore, the welded raw material is die-cut to form a pole piece 24 of a required size. An inductive sensor or a visual camera is used to detect and identify an edge of the active material layer 2412 close to the pole ear portion 242, and the edge is set as a reference edge.

[0166] According to the position of the reference edge, the adhesive tape is covered on the weld print area 243, or on the weld print area 243 and the second insulating layer 246 at the same time, or on the weld print area 243, the second insulating layer 246 and the active material layer 2412 at the same time. Thus, while the weld print area 243 is covered with the adhesive tape, the support strength between the weld print area 243 and the second insulating layer 246 is improved, and the probability of creases or cracks is reduced.

[0167] After the glue is applied, the visual camera is used to further detect the specific position of the tape, the size of the tape, and the appearance defects on the tape, thereby further improving the glue application accuracy and quality.

[0168] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0169] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery cell, comprising an electrode assembly, wherein the electrode assembly comprises a positive electrode sheet and a negative electrode sheet, characterized in that: The positive electrode sheet and / or the negative electrode sheet comprises a main body and a pole ear portion arranged on at least one side of the main body along the width direction of the pole sheet, the pole ear portion has a weld mark area, and the weld mark area is arranged on one side of the pole ear portion close to the main body; The pole piece further includes a bonding layer, the bonding layer covers the welding print area, and the bonding layer includes a base film and a glue layer coated on the surface of the base film; The bonding layer is constructed as a first insulating layer and covers the weld print area and part of the main body at the same time; wherein the main body includes a bottom layer and an active material layer stacked on the bottom layer along the thickness direction of the pole piece, the bottom layer includes a coating area and an uncoated area, the active material layer is located in the coating area, the uncoated area is located between the active material layer and the pole ear portion, and the bonding layer covers the weld print area and the uncoated area at the same time; the main body also includes a second insulating layer arranged in the uncoated area, in the width direction of the pole piece, one end of the second insulating layer is connected to the active material layer, and the other end is spaced from the pole ear portion; the bonding layer covers the weld print area and at least part of the second insulating layer at the same time, and the bonding layer is simultaneously arranged across the weld print area and at least part of the second insulating layer.

2. The battery cell according to claim 1, characterized in that: The bonding layer covers the weld print area, the second insulating layer and a portion of the active material layer at the same time.

3. The battery cell according to claim 2, characterized in that: In the width direction of the electrode sheet, the width of the adhesive layer covering the active material layer is in the range of 0 to 3 mm.

4. The battery cell according to claim 2, characterized in that: In the width direction of the pole piece, the width of the bonding layer ranges from 1 mm to 15 mm.

5. The battery cell according to claim 4, characterized in that: In the width direction of the pole piece, the width of the bonding layer ranges from 2 mm to 11 mm.

6. The battery cell according to claim 1, characterized in that: In the width direction of the pole piece, the spacing distance between the weld print area and the second insulating layer is 0 mm to 1 mm.

7. The battery cell according to claim 1, characterized in that: In the thickness direction of the pole piece, the total thickness of the adhesive layer is not greater than the thickness of the main body.

8. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 7.

9. An electrical device comprising the battery as claimed in claim 8.

10. A method for manufacturing a battery cell, characterized in that: The battery cell comprises an electrode assembly, the electrode assembly comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet and / or the negative electrode sheet comprises a main body and a pole ear portion arranged on at least one side of the main body along the width direction of the pole sheet, the pole ear portion has a weld mark area, the weld mark area is arranged on the side of the pole ear portion close to the main body; the main body comprises a bottom layer and an active material layer stacked on the bottom layer along the thickness direction of the pole sheet; the bottom layer comprises a coating area and an uncoated area, the active material layer is located in the coating area, and the uncoated area is located between the active material layer and the pole ear portion; the main body further comprises a second insulating layer arranged in the uncoated area, one end of the second insulating layer is connected to the active material layer in the width direction of the pole sheet, and the other end is spaced from the pole ear portion; The production method comprises the following steps: Die cutting, die cutting the raw material to form the pole piece; Positioning, identifying the edge of the active material layer close to the electrode ear and setting it as a reference edge; Gluing, covering the welding area with an adhesive layer according to the position of the reference edge; wherein the adhesive layer includes a base film and an adhesive layer coated on the surface of the base film; specifically, covering the welding area and at least a part of the second insulating layer with the adhesive layer according to the position of the reference edge, so that the adhesive layer is simultaneously arranged across the welding area and at least a part of the second insulating layer; Detection: Detect the position and size of the adhesive layer in the weld print area, and detect appearance defects of the adhesive layer.

11. The manufacturing method according to claim 10, characterized in that: The gluing step specifically includes: The bonding layer is simultaneously covered on the weld print area, the second insulating layer and part of the active material layer according to the position of the reference edge; wherein, in the width direction of the pole piece, the bonding layer covers the active material layer in a width range of 0 to 3 mm.

12. The manufacturing method according to claim 10, characterized in that: Before the die-cutting step, the method further comprises the following steps: Welding, identifying the edge of one side of the second insulating layer close to the pole ear as a reference edge, welding the pole ear according to the position of the reference edge and forming the weld mark area; wherein, in the width direction of the pole piece, the spacing distance between the weld mark area and the reference edge is controlled to be 0mm~1mm.

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