Winding method, electrode assembly, battery and electric equipment

Abstract

The invention is suitable for the technical field of batteries, and provides a winding method, an electrode assembly, a battery and electric equipment. The winding method comprises: providing a pole piece and a diaphragm; the pole piece is provided with a coating part coated with an active substance layer and an uncoated part not coated with the active substance layer; preparing a weak structure on a tab cutting line of the pole piece; the pole piece is divided into a first part and a second part by a weak structure, the first part comprises a coated part and a partially uncoated part, and the second part comprises the residual uncoated part; arranging the pole pieces and the diaphragms according to a preset sequence, and performing winding forming to obtain a winding body; and removing the second part to prepare the tab and the electrode assembly. According to the winding method, the electrode assembly, the battery and the electric equipment provided by the invention, the risk that the tabs are folded, cracked or damaged in the winding process can be reduced to a certain extent, and the product yield is improved.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and in particular relates to a winding method, an electrode assembly, a battery and an electrical device. Background Art

[0002] The electrode assembly is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. During the production process of the wound electrode assembly, the tabs are prone to folding, cracking or breaking. Summary of the invention

[0003] In view of the above problems, the present application provides a winding method, an electrode assembly, a battery and an electrical device, aiming to improve the technical problem that the tabs are prone to folding, cracking or damage during the winding process.

[0004] In a first aspect, an embodiment of the present application provides a winding method, comprising: providing a pole piece and a separator; the pole piece having a coated portion coated with an active material layer and an uncoated portion not coated with the active material layer; preparing a weak structure on a pole ear cutting line of the pole piece; the pole piece is separated into a first part and a second part by the weak structure, the first part comprising the coated portion and part of the uncoated portion, and the second part comprising the remaining uncoated portion; arranging the pole piece and the separator in a preset order, winding and forming, and obtaining a wound body; removing the second part to obtain a pole ear and an electrode assembly.

[0005] The winding method provided in the embodiment of the present application changes the traditional winding method of first cutting and shaping the pole ear and then winding the pole piece and the diaphragm, and changes to first preparing a weak structure on the pole ear cutting line of the pole piece, and then winding the pole piece and the diaphragm, so that the pole piece and the diaphragm can be wound before the pole ear is cut and shaped, that is, the pole piece and the diaphragm are wound in the state of the full pole ear, and a part of the pole piece (the second part) is removed after the pole piece and the diaphragm are wound and shaped to form the pole ear and the electrode assembly. The winding method provided in the embodiment of the present application helps to reduce the stress borne by the part where the pole ear is located during the winding process, thereby reducing the risk of folding, cracking and damage of the pole ear during the winding process to a certain extent, and further improving the yield rate of the electrode assembly made of the pole piece to a certain extent.

[0006] In addition, the winding method provided in the embodiment of the present application can also break the winding speed limit of the hard shell electrode assembly in the current production process to a certain extent, increase the winding speed (up to 3m / s or more), and improve the quality and production efficiency of the electrode assembly.

[0007] In some embodiments, the weak structure includes a plurality of weak parts arranged at intervals along the tab cutting line. The solution provided in this embodiment can make the connection strength between the first part and the second part higher, and can reduce the risk of partial separation of the first part and the second part during the winding process to a certain extent, so that the winding process can be carried out at a high speed and stably, which helps to improve production efficiency.

[0008] In some embodiments, the weak portion is a through hole that penetrates the pole piece along the thickness direction. The weak portion adopts the structure provided by this embodiment, which is simple in structure and easy to process.

[0009] In some embodiments, the cross-sectional shape of the through hole is circular, square or star-shaped. The through hole is arranged in the manner of this embodiment, which is convenient for design and processing.

[0010] In some embodiments, on a reference plane parallel to the pole piece, the sum of the areas of the projection figures of the weak portion is 40%-95% of the areas of the projection figures of the strip structure corresponding to the weak structure; in the extension direction of the pole tab cutting line, the size of the strip structure is equal to the size of the pole tab cutting line; in the direction perpendicular to the pole tab cutting line, the size of the strip structure is equal to the size of the weak portion. The solution provided in this embodiment can prevent the second part from being separated from the first part during the pole piece winding process, and can also make the second part easy to remove, which helps to improve production efficiency.

[0011] In some embodiments, removing the second portion includes: applying a pulling force away from the first portion to the second portion until the second portion is separated from the first portion; or applying a pulling force away from the second portion to the first portion until the second portion is separated from the first portion. The winding method provided in this embodiment is simple to operate, and when the positive electrode tab and the negative electrode tab are located at the same end of the main body of the electrode assembly, the positive electrode tab and the negative electrode tab are not prone to short circuit.

[0012] In some embodiments, the removal of the second part includes: providing a first tool and a second tool; fixing the third part of the winding body by the first tool, the third part being the part of the winding body corresponding to the position of the first part; clamping the second part by the second tool; applying a pulling force away from the first part to the second tool, or applying a pulling force away from the second part to the first tool until the second part is separated from the first part. The winding method provided in this embodiment realizes the removal of the second part by means of the first tool and the second tool, and the operation is simple and convenient.

[0013] In some embodiments, the first tool comprises two first bodies spaced apart from each other, and the two first bodies cooperate with each other to clamp the third part. The first tool adopts the solution provided in this embodiment, has a simple structure and is easy to operate.

[0014] In some embodiments, the first body has a first fitting surface that fits with the corresponding surface of the third part. The area of ​​the first fitting surface is greater than or equal to the area of ​​the corresponding surface of the third part. This makes the contact area between the first body and the third part larger and the frictional force larger, so that the first tooling can better fix the third part.

[0015] In some embodiments, the second tooling includes two second bodies spaced apart from each other, and the two second bodies are used to cooperate with each other to clamp the second part. The second tooling adopts the solution provided in this embodiment, has a simple structure, and is easy to operate.

[0016] In some embodiments, the second body has a second bonding surface that is bonded to the corresponding surface of the second part, and the area of ​​the second bonding surface is greater than or equal to the area of ​​the corresponding surface of the second part. This makes the contact area between the second body and the second part larger, and the friction force larger, so that the second tooling can better fix the second part.

[0017] In some embodiments, preparing a weak structure on a pole ear cutting line of a pole piece includes:

[0018] The weak structure is prepared on the pole ear cutting line of the pole piece by laser cutting and / or mechanical cutting. The winding method provided in this embodiment is used to facilitate the preparation of the weak structure.

[0019] In some embodiments, the winding speed in the winding forming process is 1 m / s-5 m / s. The winding speed provided in this embodiment can not only increase the yield of the electrode assembly, but also improve the processing efficiency of the electrode assembly to a certain extent.

[0020] In some embodiments, the tabs include a positive tab and a negative tab, and the positive tab and the negative tab are located at the same end of the main body of the winding body. The tabs are arranged in the manner provided in this embodiment, so that the structure of the electrode assembly can be compact.

[0021] In the second aspect, an embodiment of the present application provides an electrode assembly, which is manufactured by the winding method provided in any of the above embodiments. The electrode assembly is manufactured by the method provided in this embodiment, which can reduce the risk of folding, cracking and damage of the tab during the winding process to a certain extent, thereby improving the yield rate and product quality of the manufactured electrode assembly to a certain extent.

[0022] In a third aspect, an embodiment of the present application provides a battery, including an electrode assembly provided by any of the above embodiments. The battery adopts the electrode assembly provided by the above embodiments, which can reduce the risk of folding, cracking and damage of the tab during the winding process to a certain extent, thereby improving the yield rate and product quality of the prepared electrode assembly to a certain extent.

[0023] In a fourth aspect, an embodiment of the present application provides an electrical device, including a battery provided by any of the above embodiments. The electrical device includes a battery provided by any of the above embodiments, which can reduce the risk of folding, cracking, and damage of the tab during the winding process to a certain extent, thereby improving the yield rate and product quality of the prepared electrode assembly to a certain extent.

[0024] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0026] Figure 1 A schematic diagram of a winding method provided in some embodiments of the present application;

[0027] Figure 2 A schematic diagram of the structure of a pole piece used in some embodiments of the present application;

[0028] Figure 3 A schematic diagram of the structure of the pole piece used in other embodiments of the present application;

[0029] Figure 4 This is a schematic diagram of the structure of the winding body used in some embodiments of the present application;

[0030] Figure 5 A schematic diagram of the structure of an electrode assembly used in some embodiments of the present application;

[0031] Figure 6 for Figure 3 A local enlarged schematic diagram of the middle A;

[0032] Figure 7 for Figure 1 The operation diagram corresponding to step S4 in FIG.

[0033] Figure 8 A schematic diagram of the process of step S41 used in some embodiments of the present application;

[0034] Fig. 9 for Figure 8 The operation diagram corresponding to step S414;

[0035] Fig.10 A schematic diagram of the structure of the first tooling and the second tooling used in some embodiments of the present application;

[0036] Fig.11 A schematic diagram of the exploded structure of a battery provided in some embodiments of the present application;

[0037] Fig.12 A schematic diagram of the exploded structure of a battery cell used in some embodiments of the present application;

[0038] Fig.13 This is a schematic diagram of the structure of a vehicle used in some embodiments of the present application.

[0039] The reference numerals in the specific implementation manner are as follows:

[0040] 1000. Vehicles;

[0041] 100, battery, 200, controller, 300, motor;

[0042] 10. box body, 11. first assembly, 12. second assembly;

[0043] 20. Battery cell, 21. End cover, 21a. Electrode terminal, 22. Shell, 23. Electrode assembly, 24. Tab; 25. First tooling; 26. Second tooling; 27. Winding body;

[0044] 231, pole piece, 232, diaphragm, 2311, coated portion, 2312, uncoated portion, 2313, pole ear cutting line, 233, weak structure, 2331, weak portion, 234, first portion, 235, second portion, 251, first body, 252, first fitting surface, 261, second body, 262, second fitting surface, 241, positive pole ear, 242, negative pole ear;

[0045] F. Tension. DETAILED DESCRIPTION

[0046] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0048] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0049] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, and / or B can represent: A exists alone, and B exists at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0051] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0052] In the description of the embodiments of the present application, the technical 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0053] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral 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, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0054] 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.

[0055] The component where the electrochemical reaction occurs in the battery cell is the electrode assembly. One battery cell may contain one or more electrode assemblies. The electrode assembly is mainly formed by winding or stacking the positive electrode sheet and the negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet and the negative electrode sheet respectively include a current collector and an active material layer. The current collector has a coated portion coated with an active material layer and an uncoated portion not coated with the active material layer along the width direction of the electrode sheet. During the forming process of the electrode sheet, after the active material layer is usually coated on the current collector, the area of ​​the current collector not coated with the active material layer (i.e., the uncoated portion mentioned above) is cut to form the pole ear. Among them, the part of the positive electrode sheet and the negative electrode sheet with active material constitutes the main body of the electrode assembly. The positive pole ear and the negative pole ear can be located at one end of the main body or at both ends of the main body respectively. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the pole ear connects the electrode terminal to form a current loop.

[0056] In the production process of wound electrode assemblies, the tab cutting and forming operation is generally carried out first, and the pole piece and diaphragm are wound after the tab is formed. Since the tab is a protruding main body, thin, discontinuous structure, and the winding speed is generally fast, the tab is prone to folding, cracking, and damage due to excessive stress during the high-speed winding process.

[0057] In order to improve the above problems, the embodiment of the present application provides a winding method, which changes the traditional winding method of first cutting and forming the pole ear and then winding the pole piece and the diaphragm, and changes it to first preparing a weak structure on the pole ear cutting line of the pole piece, and then winding the pole piece and the diaphragm, so that the pole piece and the diaphragm can be wound before the pole ear is cut and formed, that is, the pole piece and the diaphragm are wound in the state of the full pole ear, and then a part of the pole piece is removed after the pole piece and the diaphragm are wound and formed to form the pole ear and the electrode assembly. The winding method provided by the embodiment of the present application helps to reduce the stress on the part where the pole ear is located during the winding process, thereby reducing the risk of the pole ear being folded, cracked and damaged during the winding process to a certain extent, and further improving the yield rate of the electrode assembly made of the pole piece to a certain extent.

[0058] The winding method disclosed in the embodiment of the present application can be used for winding and forming electrode assemblies, and can also be used for winding and forming other materials in other production processes.

[0059] Please refer to Figure 1 As shown, the winding method comprises the following steps:

[0060] S1. Provide pole pieces and diaphragms. Figure 2 As shown, the pole piece 231 has a coated portion 2311 coated with an active material layer and an uncoated portion 2312 not coated with the active material layer.

[0061] The pole piece 231 mentioned here includes at least one positive pole piece and one negative pole piece. The pole piece 231 has the above-mentioned coated portion 2311 and uncoated portion 2312. It should be noted that the pole tabs in each pole piece 231 in this step are all in an uncut state, that is, they are all in a full pole tab state.

[0062] S2, preparing a weak structure 233 on the pole ear cutting line 2313 of the pole piece 231, such as Figure 2 and Figure 3 It should be noted that Figure 2 The solid line extending horizontally in the figure is the separation line between the coated portion 2311 and the uncoated portion 2312, and the dotted line is the pole ear cutting line 2313. The pole piece 231 is separated into a first portion 234 and a second portion 235 by a weak structure 233. The first portion 234 includes the coated portion 2311 and part of the uncoated portion 2312, and the second portion 235 includes the remaining uncoated portion 2312.

[0063] The above-mentioned tab cutting line 2313 refers to the cutting path of a cutting tool (such as a cutting knife, laser, etc.) in the process of cutting the area of ​​the current collector in the electrode sheet 231 that is not coated with the active material layer (that is, the above-mentioned uncoated part 2312) to form a tab.

[0064] The weak structure 233 may be a continuous structure or a discontinuous structure, such as a hole penetrating the pole piece 231 along the thickness direction, or a groove or notch sunken into the pole piece 231 along the thickness direction, etc., which may be determined according to the use requirements. It is understood that the mechanical strength of the weak structure 233 is generally less than the mechanical strength of other areas of the pole piece 231 (areas other than the area where the weak structure 233 is located).

[0065] The first part 234 and the second part 235 are two parts respectively arranged on both sides of the tab cutting line 2313, and the two parts can be connected to each other. Among them, the partially uncoated part 2312 in the first part 234 corresponds to the part where the tab is located, and the second part 235 is the part of the pole piece 231 after removing the first part 234. Generally, the volume of the second part 235 is smaller than the volume of the first part 234. In other cases, the volume of the second part 235 can also be equal to or greater than the volume of the first part 234, which is not limited here.

[0066] S3, arrange the pole pieces and the diaphragm in a preset order, and wind them to form a winding body 27, such as Figure 4 shown.

[0067] Since the electrode assembly includes at least one positive electrode sheet and one negative electrode sheet, the preset order may be stacked in sequence in the arrangement of negative electrode sheet, separator, positive electrode sheet, separator, or in the arrangement of positive electrode sheet, separator, negative electrode sheet, separator. When the electrode assembly uses multiple negative electrode sheets and multiple positive electrode sheets, the stacking principle is equivalent to the above, which will not be described in detail here.

[0068] The winding forming may be a process of winding the pole pieces and the diaphragm arranged in a preset order around a virtual axis, and may also be followed by hot pressing or cold pressing.

[0069] The winding body 27 can be cylindrical, square, or in other shapes, depending on the usage requirements.

[0070] S4, removing the second part, and obtaining the tab 24 and the electrode assembly 23, such as Figure 5 shown.

[0071] The second part can be removed from the first part by secondary cutting or pulling according to usage needs.

[0072] The winding method provided in the embodiment of the present application changes the traditional winding method of first cutting and forming the pole ear and then winding the pole piece 231 and the diaphragm, and changes to first preparing a weak structure 233 on the pole ear cutting line 2313 of the pole piece 231, and then winding the pole piece 231 and the diaphragm, so that the pole piece 231 and the diaphragm can be wound before the pole ear is cut and formed, that is, the pole piece 231 and the diaphragm are wound in the state of the full pole ear, and a part of the pole piece 231 (the second part 235) is removed after the pole piece 231 and the diaphragm are wound and formed to form the pole ear and the electrode assembly. The winding method provided in the embodiment of the present application helps to reduce the stress borne by the part where the pole ear is located during the winding process, thereby reducing the risk of the pole ear being folded, cracked and damaged during the winding process to a certain extent, and further improving the yield rate of the electrode assembly made of the pole piece 231 to a certain extent.

[0073] In addition, the winding method provided in the embodiment of the present application can also break the winding speed limit of the hard shell electrode assembly in the current production process to a certain extent, increase the winding speed, and improve the quality and production efficiency of the electrode assembly.

[0074] like Figure 3 and Figure 6 As shown, in some embodiments, the weak structure 233 includes a plurality of weak portions 2331 arranged at intervals.

[0075] The weak portion 2331 may be a hole that penetrates the pole piece 231 along the thickness direction, or a groove or notch that is recessed into the pole piece 231 along the thickness direction, etc., which may be determined according to the use requirements. It is understood that the mechanical strength of the weak portion 2331 is generally less than the mechanical strength of other areas of the pole piece 231 (areas other than the area where the weak portion 2331 is located).

[0076] The spaced arrangement means that there is a space between two adjacent weak portions 2331 .

[0077] By adopting the solution provided in this embodiment, the connection strength between the first part 234 and the second part 235 can be increased, and the risk of partial separation of the first part 234 and the second part 235 during the winding process can be reduced to a certain extent. In this way, the winding process can be carried out at a high speed and stably, which helps to improve production efficiency.

[0078] In some embodiments, the weak portion 2331 is a through hole that penetrates the pole piece 231 along the thickness direction.

[0079] The weak portion 2331 adopts the structure provided in this embodiment, which has a simple structure and is easy to process.

[0080] In some embodiments, the cross-sectional shape of the through hole is circular, square, star-shaped, etc.

[0081] The cross section refers to the cross section obtained by cutting the through hole with a plane perpendicular to the thickness direction of the pole piece 231. The cross-sectional shape refers to the shape of the above cross section.

[0082] It is understandable that the shape of the through hole can be selected from any of the above-mentioned shapes according to the use requirements, or other shapes can be adopted, which can be determined according to the use requirements.

[0083] The through hole is arranged in the manner of this embodiment, which is convenient for design and processing.

[0084] In some embodiments, on a reference plane parallel to the pole piece 231, the sum of the areas of the projection figures of the weak portion 2331 is 40%-95% of the area of ​​the projection figures of the strip structure corresponding to the weak structure 233, for example, it can be 40%-70%, 40%-75%, 40%-60%, etc., and can also be 40%, 50%, 60%, 70%, 80%, etc., which can be determined according to the specific needs of use. In the extension direction of the pole tab cutting line 2313, the size of the strip structure is equal to the size of the pole tab cutting line 2313. In the direction perpendicular to the pole tab cutting line 2313, the size of the strip structure is equal to the size of the weak portion 2331.

[0085] Since the thickness of the pole piece 231 is relatively thin, although the pole piece 231 is a three-dimensional structure, its side surface can be ignored. Therefore, the above-mentioned parallel to the pole piece 231 refers to the first surface or the second surface parallel to the pole piece 231. The first surface and the second surface are the surfaces with the largest area and relatively arranged in the sheet body.

[0086] The strip structure is a continuous structure extending along the extension direction of the tab cutting line 2313, and has a certain width and length. Its length is equal to the length of the tab cutting line 2313, and its width is equal to the width of the weak portion 2331. The above length refers to the size of the strip structure in the extension direction of the tab cutting line 2313, and the width refers to the size of the strip structure in a direction perpendicular to the extension direction of the tab cutting line 2313.

[0087] By adopting the solution provided in this embodiment, the second part 235 can be prevented from being separated from the first part 234 during the winding process of the pole piece 231, and the second part 235 can be easily removed, which helps to improve production efficiency.

[0088] In some embodiments, the above step S4 of removing the second portion 235 includes at least the following steps:

[0089] S41, applying a pulling force F away from the first part 234 to the second part 235 until the second part 235 is separated from the first part 234, as shown in FIG. Figure 7 shown.

[0090] The pulling force F away from the first portion 234 is generally a force extending along the axis of the wound component and acting in a direction away from the first portion 234. In other cases, the pulling force away from the first portion 234 may also be a force extending at an acute angle along the axis of the wound component and acting in a direction away from the first portion 234.

[0091] This step can be achieved by fixing the first part 234 with the help of operating tools such as tooling and manipulators, and applying a pulling force away from the first part 234 to the second part 235. It can also be achieved by applying mutually diverging forces to the first part 234 and the second part 235 with the help of operating tools such as tooling and manipulators. The appropriate operating tools and operating methods can be selected according to the processing conditions, and are not limited here. The above-mentioned tooling can be a clamp, a pressing block, etc., which can be determined according to the needs of use. The scheme provided in this embodiment is used to perform the processing of step S4, and the operation method is simple, and when the positive electrode tab 241 and the negative electrode tab 242 are located at the same end of the main body of the electrode assembly, the positive electrode tab 241 and the negative electrode tab 242 are not prone to short circuit.

[0092] In some other embodiments, the above step S4 of removing the second portion 235 includes at least the following steps:

[0093] S42 , applying a pulling force F′ to the first portion 234 away from the second portion 235 , until the second portion 235 is separated from the first portion 234 .

[0094] The pulling force F' away from the second portion 235 is generally a force extending along the axis of the wound component and acting in a direction away from the second portion 235. In other cases, the pulling force away from the second portion 235 may also be a force extending at an acute angle along the axis of the wound component and acting in a direction away from the second portion 235.

[0095] This step can be achieved by fixing the second part 235 with the help of operating tools such as tooling and manipulators, and applying a pulling force away from the second part 235 to the first part 234. It can also be achieved by applying mutually diverging forces to the first part 234 and the second part 235 with the help of operating tools such as tooling and manipulators. The appropriate operating tools and operating methods can be selected according to the processing conditions, and are not limited here. The above-mentioned tooling can be a clamp, a pressing block, etc., which can be determined according to the needs of use. The scheme provided in this embodiment is used to perform the processing of step S4, and the operation method is simple, and when the positive electrode tab 241 and the negative electrode tab 242 are located at the same end of the main body of the electrode assembly, the positive electrode tab 241 and the negative electrode tab 242 are not prone to short circuit.

[0096] In some embodiments, Figure 8 and Fig. 9 As shown, the above step S4 of removing the second portion 235 includes at least the following steps:

[0097] S411 , providing a first tool 25 and a second tool 26 .

[0098] The first tooling 25 may be composed of one or more parts. When the first tooling 25 includes multiple parts, the multiple parts may be combined to form an integral structure or may be arranged at intervals, which may be determined according to the use requirements. The second tooling 26 may be composed of one or more parts. When the second tooling 26 includes multiple parts, the multiple parts may be combined to form an integral structure or may be arranged at intervals, which may be determined according to the use requirements. The structures of the second tooling 26 and the first tooling 25 may be the same or different, which may be determined according to the use requirements.

[0099] S412, fixing the third portion of the winding body 27 by the first tooling 25, where the third portion is the portion of the winding body 27 corresponding to the first portion.

[0100] The first fixture 25 can fix the third part of the winding body 27 by pressing, clamping, or any one or more methods. For example, when the first fixture 25 is a clamp, the third part of the winding body can be fixed by clamping; when the first fixture 25 is a pressing block, the third part of the winding body can be fixed by pressing; when the first fixture 25 is other structures, the third part of the winding body can be fixed by other methods.

[0101] S413 , clamp the second part 235 by the second tooling 26 .

[0102] The second tooling 26 can adopt a clamp currently available on the market that can achieve clamping of the second part 235 , or can also be provided with a structure that can achieve clamping of the second part 235 according to usage requirements, and the specific structure can be determined according to usage requirements.

[0103] S414 , applying a pulling force F away from the first part 234 to the second tooling 26 , or applying a pulling force away from the second part 235 to the first tooling 25 , until the second part 235 is separated from the first part 234 .

[0104] The winding method provided in this embodiment realizes the removal of the second portion 235 by means of the first tooling 25 and the second tooling 26 , and the operation is simple and convenient.

[0105] In some embodiments, Fig.10 As shown, the first tool 25 includes two first bodies 251 arranged at intervals. The two first bodies 251 are used to cooperate with each other to clamp the third part.

[0106] The first body 251 may be an integrally formed structure, or may include a plurality of parts. When the first body 251 includes a plurality of parts, the plurality of parts may be combined to form an integral structure, or may be arranged at intervals, depending on the specific use requirements.

[0107] The interval arrangement means that there is an interval between the two first bodies 251. The two first bodies 251 can be connected into an integral structure through one or more connecting structures or connecting members, or can be separated and arranged, which can be determined according to the use requirements.

[0108] The first tool 25 adopts the solution provided in this embodiment, which has a simple structure and is easy to operate.

[0109] In some embodiments, the first body 251 has a first fitting surface 252 that fits with a corresponding surface of the third portion.

[0110] The setting of the first fitting surface 252 enables the first body 251 and the third part to be in surface contact, so that the contact area and friction between the two are larger, thereby enabling the first tooling 25 to better fix the third part.

[0111] In some embodiments, the area of ​​the first fitting surface 252 is greater than or equal to the area of ​​the corresponding surface of the third part, so that the contact area and friction between the first body 251 and the third part are larger, so that the first tool 25 can better fix the third part.

[0112] In some embodiments, the first body 251 is a plate or a block. The first body 251 adopts the structure provided by this embodiment, which is simple in structure and easy to prepare.

[0113] In some embodiments, Fig.10 As shown, the second tool 26 includes two second bodies 261 arranged at intervals. The two second bodies 261 are used to cooperate with each other to clamp the second part 235.

[0114] The second body 261 may be an integrally formed structure, or may include a plurality of parts. When the second body 261 includes a plurality of parts, the plurality of parts may be combined to form an integral structure, or may be arranged at intervals, which may be determined according to the use requirements.

[0115] The two second bodies 261 may be connected into an integral structure via one or more connecting structures or connecting members, or may be separately arranged, depending on the specific use requirements.

[0116] The second tooling 26 adopts the solution provided in this embodiment, which has a simple structure and is easy to operate.

[0117] In some embodiments, the second body 261 has a second fitting surface 262 that fits with a corresponding surface of the second portion 235 .

[0118] The second fitting surface 262 is provided so that the second body 261 and the second part 235 are in surface contact, so that the contact area and friction force between the two are larger, so that the second tooling 26 can better fix the second part 235.

[0119] In some embodiments, the area of ​​the second fitting surface 262 is greater than or equal to the area of ​​the corresponding surface of the second portion 235. This makes the contact area between the second body 261 and the second portion 235 larger and the frictional force larger, so that the second tooling 26 can better fix the second portion 235.

[0120] In some embodiments, the second body 261 is a plate or a block. The second body 261 adopts the structure provided by this embodiment, which is simple in structure and easy to prepare.

[0121] In some embodiments, the above step S2 of preparing the weak structure 233 on the tab cutting line 2313 of the pole piece 231 includes at least the following steps:

[0122] The weak structure 233 is prepared on the pole ear cutting line 2313 of the pole piece 231 by laser cutting and / or mechanical cutting.

[0123] The laser cutting method can be performed by laser die-cutting equipment, and the mechanical cutting method can be performed by mechanical die-cutting equipment. The preparation of the weak structure 233 on the pole ear cutting line 2313 of the pole piece 231 by laser cutting and / or mechanical cutting means that the preparation of the weak structure 233 can be completed by only laser cutting, or only mechanical cutting, or partly by laser cutting and the other part by mechanical cutting, which can be determined according to the use requirements.

[0124] The step S2 is performed in the manner provided in this embodiment, so as to facilitate the preparation of the weak structure 233 .

[0125] In some embodiments, the winding speed during the winding process is 1 m / s-5 m / s.

[0126] The winding speed provided in this embodiment can not only increase the yield of the electrode assembly, but also improve the processing efficiency of the electrode assembly to a certain extent.

[0127] In some embodiments, the tabs 24 include a positive tab 241 and a negative tab 242. The positive tab 241 and the negative tab 242 are located at the same end of the main body of the winding body.

[0128] The main body of the wound body refers to the portion of the wound body where the coating portion 2311 is located.

[0129] The electrode tabs are arranged in the manner provided in this embodiment, so that the structure of the electrode assembly can be compact.

[0130] In other embodiments, the tabs 24 include a positive tab 241 and a negative tab 242. The positive tab 241 and the negative tab 242 are located at two ends of the main body of the winding body. The specific arrangement can be determined according to the use requirements.

[0131] In an embodiment of the present application, an electrode assembly is provided. The electrode assembly is manufactured by the winding method provided in any of the above embodiments.

[0132] The battery assembly disclosed in the embodiments of the present application can be used in electrical devices that use batteries as power sources or in various energy storage systems that use batteries as energy storage elements.

[0133] The electrode assembly is manufactured using the method provided in this embodiment, which can reduce the risk of problems such as folding, cracking and damage of the electrode tab during the winding process to a certain extent, thereby improving the yield and product quality of the manufactured electrode assembly to a certain extent.

[0134] According to some embodiments of the present application, the present application also provides a battery, comprising an electrode assembly of any of the above schemes.

[0135] In addition to the above-mentioned electrode assembly, the battery generally includes other structures. Fig.11 As shown, the battery 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is contained 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 assembly 11 and a second assembly 12, and the first assembly 11 and the second assembly 12 cover each other, and the first assembly 11 and the second assembly together define a storage space for accommodating the battery cell 20. The second assembly 12 may be a hollow structure with one end open, and the first assembly 11 may be a plate-like structure, and the first assembly 11 covers the open side of the second assembly, so that the first assembly 11 and the second assembly 12 jointly define a storage space; the first assembly 11 and the second assembly 12 may also be hollow structures with one side open, and the open side of the first assembly 11 covers the open side of the second assembly 12. Of course, the box body 10 formed by the first assembly 11 and the second assembly 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc. In some cases, the battery cell 20 can also be directly installed in the vehicle without the box body 10 or the shell 22 , that is, there is no need to form a battery pack 100 , and the structure of the vehicle body itself serves as a fixing structure for the battery cell 20 .

[0136] 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 100 module formed by connecting multiple battery cells 20 in series, in parallel, or in a mixed connection, and then the multiple battery 100 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.

[0137] 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.

[0138] Please refer to Fig.12 , Fig.12 The schematic diagram of the exploded structure of the battery cell 20 used in some embodiments of the present application. The battery cell 20 refers to the smallest unit constituting the battery 100. As shown in the figure, the battery cell 20 includes an end cap 21, a housing 22, an electrode assembly 23 and other functional components.

[0139] 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 to 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.

[0140] 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.

[0141] The battery 100 adopts the electrode assembly 23 provided in the above embodiment, which can reduce the risk of the tab 24 being folded, cracked, or damaged during the winding process to a certain extent, thereby improving the yield and product quality of the electrode assembly 23 to a certain extent.

[0142] According to some embodiments of the present application, the present application also provides an electrical device, comprising a battery according to any of the above schemes, and the battery is used to provide electrical energy to the electrical device.

[0143] The electrical device may be, but is 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, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0144] For ease of understanding, an electrical device in an embodiment of the present application is described by taking a vehicle 1000 as an example.

[0145] Please refer to Fig.13 , Fig.13This is a schematic diagram of the structure of a vehicle 1000 used in some embodiments of the present application. The 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, for starting, navigating and driving the vehicle 1000.

[0146] In some embodiments of the present application, the battery can be used not only as an operating power source for the vehicle 1000, but also 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.

[0147] The electrical device includes the battery provided by any of the above embodiments, which can reduce the risk of the tabs being folded, cracked, or damaged during the winding process to a certain extent, thereby improving the yield and product quality of the electrode assembly to a certain extent.

[0148] like Figures 1 to 10 As shown, according to some embodiments of the present application, a winding method is provided, comprising the following steps:

[0149] A pole piece 231 and a separator are provided; the pole piece 231 has a coated portion 2311 coated with an active material layer and an uncoated portion 2312 not coated with the active material layer;

[0150] A weak structure 233 is prepared on the pole ear cutting line 2313 of the pole piece 231; the pole piece 231 is separated into a first part 234 and a second part 235 by the weak structure 233, the first part 234 includes a coated part 2311 and a part of an uncoated part 2312, and the second part 235 includes the remaining uncoated part 2312;

[0151] Arrange the pole pieces 231 and the diaphragm in a preset order, and wind them into a winding body;

[0152] The second portion 235 is removed to obtain the tab and electrode assembly.

[0153] The weak structure 233 includes a plurality of weak portions 2331 arranged at intervals along the pole ear cutting line 2313. The weak portion 2331 is a through hole that penetrates the pole piece 231 along the thickness direction. The cross-sectional shape of the through hole is circular, square, star-shaped, etc. The above-mentioned through hole can be made by intermittently die-cutting the pole ear along the axial direction of the electrode assembly by laser. After die-cutting, the pole ear still retains the full pole ear state, but there is an intermittent opening between the pole ear and the residual material, and the opening length is L, and L satisfies: 0mm<L≤amm (the size of a can be adjusted according to product requirements, such as a can be 10mm, 5mm, etc.).

[0154] On a reference plane parallel to the pole piece 231, the sum of the areas of the projection patterns of the weak portion 2331 is 40%-95% of the areas of the projection patterns of the strip structures corresponding to the weak structures 233. In the extension direction of the tab cutting line 2313, the size of the strip structure is equal to the size of the tab cutting line 2313. In the direction perpendicular to the tab cutting line 2313, the size of the strip structure is equal to the size of the weak portion 2331.

[0155] The above-mentioned step of removing the second portion 235 includes the following steps:

[0156] Providing a first tool 25 and a second tool 26;

[0157] Fixing the third part of the winding body by the first tool 25, the third part is the part 234 of the winding body corresponding to the position of the first part;

[0158] Clamp the second part 235 by the second tool 26;

[0159] A pulling force is applied to the second tool 26 away from the first portion 234 until the second portion 235 is separated from the first portion 234 .

[0160] The first tool 25 includes two first bodies 251 spaced apart from each other, and the two first bodies 251 are used to cooperate with each other to clamp the first part 234. The first body 251 is a plate body. The first body 251 has a first fitting surface 252 that fits with the corresponding surface of the first part 234. The area of ​​the first fitting surface 252 is greater than or equal to the area of ​​the corresponding surface of the first part 234.

[0161] The second tool 26 includes two second bodies 261 spaced apart from each other, and the two second bodies 261 are used to cooperate with each other to clamp the second part 235. The second body 261 is a block, and the second body 261 has a second fitting surface 262 that fits with the corresponding surface of the second part 235. The area of ​​the second fitting surface 262 is greater than or equal to the area of ​​the corresponding surface of the second part 235.

[0162] When in use, the wound body formed after winding can be passed through the pressing and removal ear device composed of the first tooling 25 and the second tooling 26 to remove the remaining ear (i.e., the second part 235) and retain the battery cell ear (i.e., the uncoated part 2312 in the first part 234) to complete the production process of the electrode assembly.

[0163] The above-mentioned preparation of the weak structure 233 on the pole ear cutting line 2313 of the pole piece 231 includes the following steps:

[0164] The weak structure 233 is prepared on the tab cutting line 2313 of the pole piece 231 by laser cutting and / or mechanical cutting. In this process, by adjusting the laser passing path or the shape of the knife die, the tabs on the pole piece 231 are formed with intermittent cutting marks. After the cutting, the pole piece 231 still shows a full tab shape, but breakpoints have been formed between the tabs. The breakpoints are the above-mentioned through holes.

[0165] The winding speed during the winding process is 1 m / s-5 m / s, or even higher. The tabs include a positive tab 241 and a negative tab 242, and the positive tab 241 and the negative tab 242 are located at the same end of the main body of the winding body.

[0166] By adopting the winding method provided in this embodiment, the pole ear can be wound in a full-pole ear state, which helps to reduce the stress on each pole ear during the winding process, thereby reducing the probability of cracking, folding and breakage of the pole ear, and the failure rate can be reduced to 0 PPB, thereby improving the yield rate of the pole piece 231 made into a winding core and the winding quality rate. The winding method provided in this embodiment not only solves the problem of pole ear folding, cracking and breakage during high-speed winding, but also breaks through the winding speed during the battery cell production process and improves production efficiency. In addition, in the existing winding process, the pole ear is warped due to the poor incoming material state of the pole piece 231 or accidental contact during transportation. There will still be a high proportion of pole ear folding when the speed is reduced during the winding process. The winding method provided in this embodiment can completely solve the folding problem caused by poor incoming materials.

[0167] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A winding method, characterized in that: include: Provide pole pieces and diaphragms; The pole piece has a coated portion coated with an active material layer and an uncoated portion not coated with the active material layer; Prepare a weak structure on the pole lug cutting line of the pole piece; The pole piece is divided into a first part and a second part by the weak structure, the first part includes the coated part and part of the uncoated part, and the second part includes the remaining uncoated part; Arrange the pole pieces and the diaphragm in a preset order, and wind them into a shape to obtain a winding body; The second portion is removed to obtain a tab and an electrode assembly.

2. The winding method according to claim 1, characterized in that The weak structure includes a plurality of weak portions arranged at intervals along the tab cutting line.

3. The winding method according to claim 2, characterized in that: The weak portion is a through hole that penetrates the pole piece along the thickness direction.

4. The winding method according to claim 3, characterized in that: The cross-sectional shape of the through hole is circular, square or star-shaped.

5. The winding method according to any one of claims 1 to 4, characterized in that: On a reference plane parallel to the pole piece, the sum of the areas of the projection figures of the weak portion is 40%-95% of the areas of the projection figures of the strip structure corresponding to the weak structure; in the extension direction of the pole tab cutting line, the size of the strip structure is equal to the size of the pole tab cutting line; in the direction perpendicular to the pole tab cutting line, the size of the strip structure is equal to the size of the weak portion.

6. The winding method according to any one of claims 1 to 5, characterized in that: The removing the second portion comprises: applying a pulling force to the second part away from the first part until the second part is separated from the first part; Alternatively, a pulling force is applied to the first part away from the second part until the second part is separated from the first part.

7. The winding method according to any one of claims 1 to 5, characterized in that: The removing the second portion comprises: Providing a first tool and a second tool; Fixing a third portion of the winding body by using the first tool, wherein the third portion is a portion of the winding body corresponding to the first portion; clamping the second part by the second tool; A pulling force is applied to the second tooling away from the first part, or a pulling force is applied to the first tooling away from the second part, until the second part is separated from the first part.

8. The winding method according to claim 7, characterized in that: The first tooling includes two first bodies that are spaced apart from each other, and the two first bodies are used to cooperate with each other to clamp the third part.

9. The winding method according to claim 8, characterized in that: The first body has a first fitting surface fitted with a corresponding surface of the third part; The area of ​​the first fitting surface is greater than or equal to the area of ​​the corresponding surface of the third part.

10. The winding method according to claim 7, characterized in that: The second tooling includes two second bodies that are spaced apart from each other, and the two second bodies are used to cooperate with each other to clamp the second part.

11. The winding method according to claim 10, characterized in that: The second body has a second fitting surface fitted with a corresponding surface of the second portion; The area of ​​the second bonding surface is greater than or equal to the area of ​​the corresponding surface of the second portion.

12. The winding method according to any one of claims 1 to 11, characterized in that: The method of preparing a weak structure on the pole ear cutting line of the pole piece includes: A weak structure is prepared on the pole ear cutting line of the pole piece by laser cutting and / or mechanical cutting.

13. The winding method according to any one of claims 1 to 12, characterized in that: The winding speed during the winding forming process is 1m / s-5m / s.

14. The winding method according to any one of claims 1 to 13, characterized in that: The electrode tabs include a positive electrode tab and a negative electrode tab, and the positive electrode tab and the negative electrode tab are located at the same end of the main body of the winding body.

15. An electrode assembly, characterized in that: It is made by the winding method described in any one of claims 1 to 14.

16. A battery, characterized in that: Comprising the electrode assembly according to claim 15.

17. An electrical equipment, characterized in that: Comprising the battery of claim 16.

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