Electrode assembly, electrode assembly manufacturing device, battery, battery module and electric device

Abstract

The utility model discloses an electrode assembly, an electrode assembly manufacturing device, a battery, a battery module and a power utilization device, the electrode assembly comprises an anode plate, a cathode plate and a diaphragm arranged between the anode plate and the cathode plate, and the anode plate, the diaphragm and the cathode plate are wound along the winding direction to form a winding structure; each of the anode plate and the cathode plate comprises a winding starting end and a winding tail end along the winding direction, the anode plate and the cathode plate are provided with an empty foil area which is not coated with an active substance at least at the winding tail end, and the empty foil area is provided with a protective layer. The protective layers are arranged on the anode plate and the cathode plate, so that powder falling in the winding process of the electrode plates is effectively avoided, the cutting position of the winding structure can be ensured to be smooth, cutting burrs are avoided, potential safety hazards caused by powder falling and burrs are avoided, short circuit of the electrode assembly is prevented, and the winding efficiency is effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium-ion power batteries, and in particular to an electrode assembly, an electrode assembly manufacturing device, a battery, a battery module and an electrical device. Background Art

[0002] Nowadays, lithium batteries are closely related to people's lives and play an irreplaceable role in production and life fields such as communications, automobiles, medical treatment, home furnishing and security. The production process of lithium batteries is relatively long, and its production process can be roughly divided into the front-end process (electrode manufacturing), the middle-end process (cell synthesis), and the back-end process (formation packaging).

[0003] Winding is an extremely important part of the middle process of lithium batteries. In the winding process of lithium battery production, the role of the diaphragm is to separate the positive and negative electrodes of the battery. In order to achieve the purpose of barrier insulation and prevent the two electrodes from contacting and short-circuiting, the diaphragm must have an overhang relative to the positive and negative electrodes, that is, the part of the diaphragm that exceeds the positive and negative electrodes, thereby playing a role in isolation, protection and increasing stability; in addition, the anode sheet also has an overhang specification requirement relative to the cathode sheet, which can increase the surface area of ​​the electrode reaction, thereby improving the performance and efficiency of the battery.

[0004] In order to meet the above-mentioned Overhang specification requirements, the winding method in actual production is as follows Figure 1 As shown, an anode sheet, a cathode sheet and two diaphragms are wound together, wherein the diaphragm is between the cathode sheets; the specific winding process is as follows: the diaphragm is first wound 1-2 times, and then the anode is fed in, and the cathode is fed in after the anode is wound in 0.1-2 times. This method ensures that the diaphragm has an overhang relative to the positive and negative electrodes, and the anode sheet also has an overhang relative to the cathode sheet through the order of feeding. The defect of this production method is that due to the step-by-step feeding method, when cutting, it is necessary to cut the diaphragm first, then the anode, and finally the cathode. There is a defect of powder falling at the cutting position, which is easy to cause safety hazards such as short circuit. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides an electrode assembly, an electrode assembly manufacturing device, a battery, a battery module and an electrical device, which solve the problem of powder falling at the cutting position when cutting the winding body of the anode sheet, the cathode sheet and the diaphragm in the prior art.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] An electrode assembly comprises an anode sheet, a cathode sheet and a separator arranged between the anode sheet and the cathode sheet, wherein the anode sheet, the separator and the cathode sheet are wound along a winding direction to form a winding structure;

[0008] The anode sheet and the cathode sheet both include a winding start end and a winding end along the winding direction, and the anode sheet and the cathode sheet are both provided with an empty foil area not coated with active material at least at the winding end, and the empty foil area is provided with a protective layer.

[0009] Furthermore, a first empty foil region is provided at both the winding start end and the winding end end of the anode sheet, and a first protective layer is provided in the first empty foil region;

[0010] A second hollow foil area is provided at the winding start end and the winding end end of the cathode sheet, and a second protective layer is provided in the second hollow foil area.

[0011] Further, in the winding direction, the two ends of the first protective layer do not exceed the two ends of the second protective layer; and / or, along the winding axis direction, the two ends of the first protective layer do not exceed the two ends of the second protective layer.

[0012] Further, in the winding direction, two ends of the empty foil area exceed two ends of the protective layer; and / or, along the winding axis direction, two ends of the empty foil area exceed two ends of the protective layer.

[0013] Furthermore, the protective layer has a different texture and / or color from the anode sheet and the cathode sheet.

[0014] The utility model also provides an electrode assembly manufacturing device for manufacturing an electrode assembly as described in any one of the above items, including a winding mechanism, a detection mechanism and a cutting mechanism, wherein the winding mechanism is used to wind the anode sheet, the diaphragm and the cathode sheet along a winding direction; the detection mechanism is used to detect the protective layer; and the cutting mechanism is used to cut off the anode sheet, the diaphragm and the cathode sheet at the position of the protective layer.

[0015] Furthermore, the detection mechanism includes a texture sensor and / or a color sensor.

[0016] The utility model also provides a battery, comprising the electrode assembly as described in any one of the above items.

[0017] The utility model also provides a battery module, comprising the battery as described above.

[0018] The utility model also provides an electrical device, comprising the battery module as described above, wherein the battery module is used to provide power for the electrical device.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] The utility model provides an electrode assembly, an electrode assembly manufacturing device, a battery, a battery module and an electrical device. A protective layer is provided on the anode sheet and the cathode sheet to effectively avoid powder loss during the winding process of the electrode sheet. At the same time, it can ensure that the cutting part of the winding structure is smooth to avoid cutting burrs, thereby eliminating the safety hazards caused by powder loss and burrs, preventing the electrode assembly from short-circuiting, and effectively improving the winding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0022] Figure 1 It is a structural schematic diagram of an electrode assembly in the prior art;

[0023] Figure 2 A schematic diagram of an electrode assembly provided by the utility model being cut at a pre-cutting line;

[0024] Figure 3 A schematic diagram of the winding structure of an electrode assembly provided by the utility model;

[0025] Figure 4 A schematic diagram of the coating distribution of an anode sheet in an electrode assembly provided by the utility model;

[0026] Figure 5 A schematic diagram of the coating distribution of a cathode sheet in an electrode assembly provided by the utility model;

[0027] Figure 6 This is a structural schematic diagram of an electrode assembly provided by the utility model.

[0028] In the above figure: 10, winding needle; 21, anode sheet; 211, first protective layer; 212, first empty foil area; 22, cathode sheet; 221, second protective layer; 222, second empty foil area; 31, diaphragm; 41, pre-cut line; 51, material area. DETAILED DESCRIPTION

[0029] In order to make the purpose, features and advantages of the utility model more obvious and easy to understand, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the embodiment described below is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] In the description of the present utility model, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a centrally arranged component at the same time.

[0031] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0032] The utility model aims to provide a design scheme for an electrode assembly. By changing the electrode structure and setting a protective layer at the cutting position of the anode and cathode electrodes, the safety hazards caused by powder loss and burrs in the processing of the electrode can be effectively avoided, the electrode assembly can be prevented from short circuiting, and the production efficiency of the battery can be greatly improved.

[0033] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0034] Please refer to Figure 2 and Figure 3 The embodiment of the utility model provides an electrode assembly, including an anode sheet 21, a cathode sheet 22, and a separator 31 disposed between the anode sheet 21 and the cathode sheet 22; it can be understood that the electrode assembly can be formed into a winding core by winding, or can be stacked to form a laminated battery cell. For the convenience of description, this embodiment takes the winding core as an example to introduce the technical solution of the utility model.

[0035] For example, the anode sheet 21, the separator 31, and the cathode sheet 22 are wound along a winding direction to form a winding structure to constitute an electrode assembly; on this basis, preferably, the electrode assembly is a cylindrical winding structure, and the cylindrical winding structure can further simplify the manufacturing process of the battery cell.

[0036] Pre-cutting lines 41 arranged at predetermined intervals are distributed in the electrode assembly. When the winding structure is cut to form the electrode assembly, the cutting knife cuts the anode sheet 21, the cathode sheet 22 and the separator 31 from the pre-cutting lines 41. Specifically, the portions of the anode sheet 21 and the cathode sheet 22 corresponding to the pre-cutting lines 41 are provided with a protective layer, and the protective layer is used to prevent the materials in the anode sheet 21 and the cathode sheet 22 from falling when the electrode assembly is cut at the pre-cutting lines 41.

[0037] Specifically, the anode sheet 21 and the cathode sheet 22 both include a winding start end and a winding end along the winding direction, and the anode sheet 21 and the cathode sheet 22 are both provided with an empty foil area not coated with active material at least at the winding end, and the empty foil area is provided with a protective layer.

[0038] In the present embodiment, a protective layer is provided on the anode sheet 21 and the cathode sheet 22 at the portion corresponding to the pre-cut line 41, thereby preventing the material on the anode sheet 21 and the cathode sheet 22 from falling off when being cut, thereby avoiding material waste and the generation of impurities inside the battery, ensuring the stability of the battery process and the consistency of quality, and most importantly, avoiding short circuit problems caused by material falling and burrs formed by cutting, thereby greatly improving the safety performance of the battery.

[0039] Parts of the anode sheet 21 and the cathode sheet 22 corresponding to the pre-cut line 41 are provided with empty foil areas not coated with active material, and a protective layer is provided in the empty foil areas to prevent the active material from contacting the cutting edge, thereby preventing contamination of the active material.

[0040] At the same time, the setting of the protective layer can reduce the material loss caused by direct erosion of the electrolyte during the use of the battery, extend the life of the battery, thereby maintaining the stable performance of the battery and helping to improve the energy density of the battery. By setting the protective layer, the consumption of materials in the empty foil area can also be effectively reduced, avoiding unnecessary material waste.

[0041] Specifically, the anode sheet 21 is provided with a first empty foil area 212 at the winding start end and the winding end end, and the first empty foil area 212 is provided with a first protective layer 211; the cathode sheet 22 is provided with a second empty foil area 222 at the winding start end and the winding end, and the second empty foil area 222 is provided with a second protective layer 221.

[0042] In one implementation manner of this embodiment, the two ends of the first protective layer 211 do not exceed the two ends of the second protective layer 221; and / or, along the winding axis direction, the two ends of the first protective layer 211 do not exceed the two ends of the second protective layer 221.

[0043] By making the width of the second protective layer 221 greater than the width of the first protective layer 211, it is possible to ensure that the overhang of the anode sheet 21 relative to the cathode sheet 22 meets the specification requirements, reduce the risk of lithium plating, thereby improving the performance and efficiency of the battery, and further improving the cycle life and use effect of the battery.

[0044] Specifically, the anode active material is coated on the copper foil, and the cathode active material is coated on the aluminum foil. When winding, the protective layer is attached to the surface of the anode sheet 21 and the cathode sheet 22, and is arranged corresponding to the head position and the tail position of the electrode assembly; in addition, the adhesive coating can be performed in the coating process or the rolling process of the cathode sheet 22.

[0045] Specifically, the thickness of the protective layer is 0.01-2 mm, and the thickness of the protective layer after being combined with the anode sheet 21 or the cathode sheet 22 and rolled is less than 20 μm to avoid a large difference in thickness between where the protective layer is provided and where it is not provided.

[0046] In this embodiment, the protective layer allows metal ions to pass through to ensure normal performance of the electrode assembly.

[0047] In one implementation of this embodiment, the protective layer is a gel layer.

[0048] Furthermore, the protective layer is a gel glue spray layer, that is, the protective layer is sprayed with gel glue. Specifically, the gel glue is epoxy acrylate glue. The gel material is selected as the material of the protective layer, which has good adhesion and flexibility. The cutting knife during cutting is usually a hot cutting knife with a cutting dimension of 140-300°C. The gel material can adapt to high temperature environment, thereby ensuring the adhesion protection of the anode sheet 21 and the cathode sheet 22, and preventing the anode sheet 21 and the cathode sheet 22 from falling when cutting.

[0049] In another implementation of this embodiment, the protective layer is one of a polyethylene terephthalate layer, a polyvinyl chloride layer and a polyimide layer, or a combination of any two or more thereof. Polyethylene terephthalate, polyvinyl chloride and polyimide are all polymer materials, polyethylene terephthalate has high strength and hardness, polyvinyl chloride has good flexibility and impact resistance, and polyimide has high strength, high stiffness and low creep. By selecting one of the polyethylene terephthalate layer, the polyvinyl chloride layer and the polyimide layer, or combining any two or all three, as a protective layer, the head and tail positions of the electrode assembly can be effectively protected, the material breakage of the cathode sheet 22 during the cutting process can be avoided, and the stability of the manufactured battery can also be improved.

[0050] Furthermore, the central axes of the first protective layer 211 and the second protective layer 221 are both aligned with the pre-cut line 41 .

[0051] It can be understood that the two side edges of the first protective layer 211 are symmetrical about the predicted line, and the two side edges of the second protective layer 221 are symmetrical about the predicted line, so that the width of the protective layers at the head and tail positions of the cut electrode assembly are the same, which is beneficial to improving the process accuracy and consistency of the battery.

[0052] It can be understood that the anode sheet 21 and the cathode sheet 22 are coated in an intermittent manner during the coating process, and the material area 51 is set at intervals on the empty foil 51; at the same time, during the coating process, the coater uses a length measuring mechanism to determine the pre-cut line 41, and then obtains the head and tail positions of the electrode assembly; in addition, during the coating process, the width of the area where the positive and negative electrodes are not coated is set, that is, the length of the cathode empty foil is 10-400mm longer than the anode empty foil. Finally, a protective layer is set at the head and tail of the electrode assembly to obtain a first protective layer 211 provided on the anode sheet 21, or a second protective layer 221 provided on the cathode sheet 22, such as Figure 4 , Figure 5 As shown, Figure 4 The distribution diagram of the material area 51, the first empty foil area 212 and the first protective layer 211 in the anode sheet 21 is shown. Figure 5 The distribution diagram of the material area 51 , the second empty foil area 222 and the second protective layer 221 in the cathode sheet 22 is shown.

[0053] Furthermore, in this embodiment, the texture and / or color of the first protective layer 211 is different from that of the anode sheet 21 ; the texture and / or color of the second protective layer 221 is different from that of the cathode sheet 22 .

[0054] Preferably, by setting the color of the protective layer to be different from the color of the anode sheet 21 and the cathode sheet 22, and making the texture of the protective layer different from the texture color of the anode sheet 21 and the cathode sheet 22, the head and tail positions of the electrode assembly can be determined by color or texture recognition during winding, eliminating the operation of controlling the length of the electrode assembly pole pieces, which is conducive to simplifying the production process of the electrode assembly.

[0055] Based on the above embodiments, the utility model has the following beneficial effects:

[0056] 1. The utility model effectively avoids the safety hazards caused by powder loss and burrs in the winding process of the electrode sheet and prevents short circuit of the electrode assembly by providing a protective layer at the head and tail of the anode sheet 21 and the cathode sheet 22;

[0057] 2. The utility model provides a protective layer, so that the cathode sheet 22 and the diaphragm 31 do not need to be cut separately during cutting. It only needs to cut the two layers of diaphragm 31 and the positive and negative current collectors along the pre-cut line 41, thereby reducing the number of required cutting mechanisms and improving the winding efficiency. At the same time, due to the provision of the protective layer, the material area can be avoided during cutting, effectively extending the service life of the cutter;

[0058] 3. Compared with other processes, the utility model reduces the slurry input in the production of pole pieces, completely avoids the contact between the cutter and the material area during cutting, and does not generate dust and foreign matter due to the falling of materials.

[0059] 4. When winding, the head and tail positions of the electrode assembly can be determined only by color or texture recognition, which replaces the use of mark holes to identify the cutting position. There is no need to control the length of the winding electrode. It only needs to distinguish the protective layer color or texture sensing to determine the final cutting position.

[0060] On the basis of the foregoing embodiments, this embodiment provides an electrode assembly manufacturing device for manufacturing an electrode assembly, including a winding mechanism, a detection mechanism and a cutting mechanism, wherein the winding mechanism is used to wind the anode sheet 21, the diaphragm 31 and the cathode sheet 22 along a winding direction; the detection mechanism is used to detect the protective layer; and the cutting mechanism is used to cut off the anode sheet 21, the diaphragm 31 and the cathode sheet 22 at the position of the protective layer.

[0061] Furthermore, the electrode assembly manufacturing device includes an identification device, which is used to identify the protective layer on the electrode assembly and cut the electrode assembly from the position where the protective layer is located.

[0062] Among them, a texture sensor and / or a color sensor is arranged on the detection mechanism, so that the head position and the tail position of the electrode assembly can be determined by color or texture recognition. The head position and the tail position of the electrode assembly can be determined by color recognition or texture recognition, which replaces the process of controlling the length of the electrode piece by using the Mark hole. There is no need to control the length of the winding electrode piece. It is only necessary to distinguish the final cutting position by distinguishing the color of the protective layer. The operation of controlling the length of the electrode piece of the electrode assembly is eliminated, which is conducive to simplifying the production process of the electrode assembly.

[0063] It can be understood that when making an electrode assembly, the anode sheet 21, the separator 31 and the cathode sheet 22 are stacked and assembled, the separator 31 separates the anode sheet 21 and the cathode sheet 22, and after the anode sheet 21, the cathode sheet 22 and the separator 31 are wound on the winding needle 10 to a predetermined length, they are cut at the pre-cut line 41 to obtain an electrode assembly.

[0064] In this embodiment, a protective layer is provided on the anode sheet 21 and the cathode sheet 22 to effectively avoid powder loss during the winding process of the electrode sheets. At the same time, it can ensure that the cutting of the winding structure is smooth and avoid cutting burrs, thereby eliminating the safety hazards caused by powder loss and burrs, preventing short circuit of the electrode assembly, and effectively improving the winding efficiency.

[0065] Based on the above embodiments, the utility model further provides a battery, comprising the electrode assembly as described above, the electrode assembly is placed inside the battery housing and sealed to obtain a finished battery. It is understandable that the battery housing is usually made of metal to ensure the safety and stability of the battery.

[0066] Among them, the electrode assembly is provided with a hollow foil area and a protective layer in sequence from the edge to the middle, and the materials in the anode sheet 21 and the cathode sheet 22 will not fall off due to cutting, so the performance stability of the battery is relatively high.

[0067] Based on the aforementioned embodiments, the utility model further provides a battery module, including the battery as described above, the battery including an electrode assembly, and other structures of the electrode assembly can refer to the previous related description.

[0068] Based on the aforementioned embodiments, the utility model further provides an electrical device, including the battery module as described above, wherein the battery module is used to provide power to the electrical device, and other structures of the battery module may refer to the previous related descriptions.

[0069] As described above, the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. An electrode assembly, characterized in that: It comprises an anode sheet (21), a cathode sheet (22), and a separator (31) arranged between the anode sheet (21) and the cathode sheet (22), wherein the anode sheet (21), the separator (31), and the cathode sheet (22) are wound along a winding direction to form a winding structure; The anode sheet (21) and the cathode sheet (22) both include a winding start end and a winding end along the winding direction, and the anode sheet (21) and the cathode sheet (22) are both provided with an empty foil area not coated with active material at least at the winding end, and the empty foil area is provided with a protective layer.

2. The electrode assembly according to claim 1, characterized in that: The winding start end and the winding end end of the anode sheet (21) are both provided with a first empty foil area (212), and a first protective layer (211) is provided in the first empty foil area (212); The winding start end and the winding end end of the cathode sheet (22) are both provided with a second empty foil area (222), and a second protective layer (221) is provided in the second empty foil area (222).

3. The electrode assembly according to claim 2, characterized in that: In the winding direction, the two ends of the first protective layer (211) do not exceed the two ends of the second protective layer (221); and / or, along the winding axis direction, the two ends of the first protective layer (211) do not exceed the two ends of the second protective layer (221).

4. The electrode assembly according to claim 1, characterized in that: In the winding direction, two ends of the empty foil area exceed two ends of the protective layer; and / or, along the winding axis direction, two ends of the empty foil area exceed two ends of the protective layer.

5. The electrode assembly according to claim 1, characterized in that: The protective layer (211) has a different texture and / or color from the anode sheet (21) and the cathode sheet (22).

6. An electrode assembly manufacturing device, characterized in that: Used to manufacture the electrode assembly as described in any one of claims 1 to 5, comprising a winding mechanism, a detection mechanism and a cutting mechanism, wherein the winding mechanism is used to wind the anode sheet (21), the diaphragm (31) and the cathode sheet (22) along a winding direction; the detection mechanism is used to detect the protective layer; and the cutting mechanism is used to cut the anode sheet (21), the diaphragm (31) and the cathode sheet (22) at the position of the protective layer.

7. The electrode assembly manufacturing device according to claim 6, characterized in that: The detection mechanism includes a texture sensor and / or a color sensor.

8. A battery, characterized in that: Comprising the electrode assembly according to any one of claims 1 to 5.

9. A battery module, characterized in that: Comprising the battery as claimed in claim 8.

10. An electrical device, characterized in that: Comprising the battery as claimed in claim 8 or the battery module as claimed in claim 9.

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