Foil for battery, battery pole piece and battery

Abstract

The utility model discloses a foil for a battery, a battery pole piece and the battery. The foil for the battery comprises a base layer, a material layer and an insulating layer, the base layer comprises a material area, coating areas and an empty foil area which are arranged in parallel, the coating areas are arranged on the two sides of the material area respectively, and the empty foil area is arranged on the side, away from the material area, of each coating area; the material layer is arranged on the surface of the material area; and the insulating layer is arranged on the surface of the coating area. Therefore, the arrangement of the insulating layer is similar to a protective layer of a foil, and when the tab is cut, the insulating layer can play a certain buffering role, so that the probability of generating burrs is reduced, the bonding force between the base layer and the insulating layer is generally enhanced, and the generation of burrs can be reduced in the cutting process. Besides, when the adhesive tape is attached to the tab of the battery cell in the later period, the risk that burrs pierce the adhesive tape can be reduced, and the adhesive tape and the insulating layer are arranged in an overlapped manner, so that double insulation protection can be provided for the tab of the battery.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a foil for a battery, a battery electrode sheet and a battery. Background Art

[0002] With the development of modern society and the enhancement of people's environmental protection awareness, more and more new energy devices have been developed and utilized. Electric vehicles powered by electric energy generally need to use high-capacity power batteries as power sources. These power batteries should not only have high capacity but also good safety performance.

[0003] In the production and manufacturing process of existing power batteries, high-temperature adhesive paper is usually pasted on the surface of the tab. The high-temperature adhesive paper can prevent the slag from falling and burning the tab during the cover plate welding, and prevent the tab from bending and directly contacting the aluminum shell after the battery cell is put into the shell, resulting in battery short circuit. As the number of battery cycles increases, both the temperature rise and the corrosion of the electrolyte on the adhesive paper will cause the viscosity to decrease, and there may be a risk of the adhesive paper falling off. In addition, burrs are easily generated during the process of die-cutting the tab from the electrode sheet, which can pierce the adhesive paper, all of which have a negative impact on the safety performance of the battery. Summary of the Utility Model

[0004] In view of the above existing situation, the present application provides a foil for a battery, a battery electrode sheet and a battery to reduce the burrs generated during the process of cutting out the tab.

[0005] To achieve the above object, the first aspect of the utility model provides a foil for a battery, which includes: a base layer, the base layer includes a material area, a coating area and an empty foil area arranged in parallel with each other, wherein the coating areas are respectively arranged on both sides of the material area, and the empty foil area is arranged on the side of the coating area away from the material area; a material layer, the material layer is arranged on the surface of the material area; and an insulating layer, the insulating layer is arranged on the surface of the coating area.

[0006] Optionally, in the foil for a battery involved in the utility model, a gap is provided between the material layer and the insulating layer.

[0007] Optionally, in the foil for a battery involved in the utility model, the thickness of the insulating layer is between 10 μm and 20 μm.

[0008] Optionally, in the foil for a battery involved in the utility model, the insulating layer includes one of silicon dioxide nano-powder, low-density polyethylene, boehmite, and silicon nitride nano-microspheres.

[0009] Optionally, in the foil for a battery involved in the utility model, the width of the material area is greater than the total width of the coating area and the empty foil area.

[0010] In the foil for a battery related to the utility model, optionally, the width of the empty foil area is greater than or equal to the width of the coating area.

[0011] In the foil for a battery related to the utility model, optionally, the ratio of the width of the insulating layer to the width of the empty foil area is 0.5 - 1.

[0012] In the foil for a battery related to the utility model, optionally, the coating area includes a first coating area and a second coating area respectively located on both sides of the material area; the empty foil area includes a first empty foil area located away from the material area of the first coating area, and the empty foil area further includes a second empty foil area located away from the material area of the second coating area; the first empty foil area, the first coating area, the material area, the second coating area, and the second empty foil area form a combined area; the foil includes a plurality of the combined areas, and the plurality of combined areas are arranged in sequence along the width direction of the foil, and the first empty foil area of any one of the combined areas is connected to the second empty foil area of the adjacent combined area.

[0013] In the foil for a battery related to the utility model, optionally, the widths of the first empty foil area and the second empty foil area are equal.

[0014] The second aspect of the present utility model provides a battery electrode sheet, including a foil for a battery, the coating area includes a plurality of spaced coating parts arranged along the length direction of the material area, and the empty foil area includes a plurality of spaced empty foil parts arranged along the length direction of the material area; the plurality of empty foil parts and the plurality of coating parts are arranged in one-to-one correspondence and constitute the tabs of the battery electrode sheet.

[0015] The third aspect of the present utility model provides a battery, including a battery electrode sheet in a rolled state.

[0016] The foil for a battery related to the present utility model includes a base layer, a material layer, and an insulating layer. Among them, the base layer includes a material area, a coating area, and an empty foil area, and the coating area and the empty foil area are used to cut out the tabs of the battery, and the insulating layer is provided on the surface of the coating area. According to this structure, the setting of the insulating layer is similar to the protective layer of the foil. When the external machine cuts out the tabs, the insulating layer can play a certain buffering role, thereby reducing the probability of generating burrs when cutting the base layer, and the adhesion between the base layer and the insulating layer usually increases, which can also reduce the generation of burrs during the cutting process. In addition, when the battery cell pastes adhesive tape on the tabs at a later stage, the risk of burrs piercing the adhesive tape can be reduced, and the adhesive tape and the insulating layer are stacked, which can also provide double insulation protection for the tabs of the battery, further improving the safety performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0018] To more fully understand the present application and its beneficial effects, the following will be described in conjunction with the accompanying drawings, where the same reference numerals represent the same parts in the following description.

[0019] Figure 1 It is a schematic diagram showing the overall structure of a single foil before coating involved in the present application.

[0020] Figure 2 It is a schematic diagram showing the overall structure of a single foil after coating involved in the present application.

[0021] Figure 3 It is a schematic diagram showing the overall structure of a double foil after coating involved in the present application.

[0022] Figure 4 It is a schematic diagram showing the overall structure of a quadruple foil after coating involved in the present application.

[0023] Figure 5 It is a schematic diagram showing the overall structure of a single foil after cutting out the tab involved in the present application.

[0024] Figure 6 It is a schematic diagram showing the overall structure of the electrode sheet involved in the present application.

[0025] Figure 7 It is a schematic diagram showing the partial structure of the battery involved in the present application.

[0026] Reference numerals: 10, base layer; 11, material area; 12, coating area; 121, coating part; 122, first coating area; 123, second coating area; 13, empty foil area; 131, first empty foil area; 132, second empty foil area; 133, empty foil part; 20, material layer; 30, insulating layer; 40, tab group; 41, connecting section; 42, insulating section; 50, main body part; 60, connecting piece. Detailed implementation manners

[0027] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present application will be described in detail. In the following description, the same reference numerals are given to the same components, and repeated descriptions are omitted. In addition, the drawings are only schematic diagrams, and the dimensional ratios between components or the shapes of components may be different from the actual ones. It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0028] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0029] With the development of modern society and the enhancement of people's environmental protection awareness, more and more new energy devices have been developed and utilized. Electric vehicles powered by electric energy generally need to use power batteries with large capacity as the power source. These power batteries should not only have high capacity but also good safety. However, in the production and manufacturing process of existing power batteries, high-temperature adhesive tapes are usually pasted on the surface of the tabs. The high-temperature adhesive tapes can prevent the molten slag from dropping and burning the tabs during the welding of the cover plate, and prevent the tabs from bending and directly contacting the aluminum shell after the battery cell is put into the shell, resulting in battery short circuit. As the number of battery cycles increases, both the temperature rise and the corrosion of the electrolyte on the adhesive tape will cause the viscosity to decrease, and there may be a risk of the adhesive tape falling off. In addition, burrs are easily generated during the process of die-cutting the tabs from the electrode plate, which may pierce the adhesive tape, all of which have a negative impact on the safety performance of the battery.

[0030] Therefore, with reference to Figures 1 to 3 , a foil for a battery is provided in the first aspect of the present application, which includes a base layer 10, a material layer 20 and an insulating layer 30. The base layer 10 includes a material area 11, a coating area 12 and a blank foil area 13 arranged in parallel with each other. Among them, along the width direction of the material area 11, coating areas 12 are respectively provided on both sides of the material area 11, and a blank foil area 13 is provided on the side of the coating area 12 away from the material area 11; the material layer 20 is disposed on the surface of the material area 11; and the insulating layer 30 is disposed on the surface of the coating area 12.

[0031] According to the above structure, the insulating layer 30 is provided similar to the protective layer of the foil. When the external machine cuts the tab, the insulating layer 30 can play a certain buffering role, thereby reducing the probability of burrs generated when cutting the base layer 10. Moreover, the adhesion between the base layer 10 and the insulating layer 30 is usually enhanced, which can also reduce the generation of burrs during the cutting process. In addition, when the adhesive tape is attached to the tab of the battery cell in the later stage, the risk of burrs piercing the adhesive tape can be reduced. And the adhesive tape and the insulating layer 30 are stacked, which can also provide double insulation protection for the tab of the battery, further improving the safety performance of the battery.

[0032] In the field of battery production and manufacturing, the width of the foil is usually described by "width". Narrower foils can be used as single-width foils, such as Figure 1 the schematic diagram of the single-width foil shown, while wider foils can be used as multi-width foils, such as Figure 3 the schematic diagram of the double-width foil and Figure 4 the schematic diagram of the four-width foil shown. In this application, the distribution of the material area 11, the coating area 12, and the empty foil area 13 of the single-width foil and the multi-width foil still follows the settings of the above embodiments.

[0033] Specifically, to form a pole piece from a single-width foil, it can be cut from the middle of the material area 11. As Figure 5 shows the single-width foil after the tab is removed, and then it can be cut in the middle to form two pole pieces. As Figure 6 shows the schematic diagram of one of the pole pieces after cutting. In the related art, the staff would wind the pole piece into a battery cell and then coat the insulating layer 30 at the tab. This coating method has low efficiency and requires step-by-step coating of each individual tab. In this application, for a single-width foil, the two insulating layers 30 on both sides of the material area 11 can be coated simultaneously, or four insulating layers 30 can be coated simultaneously in a double-width foil, and multiple insulating layers 30 can be coated in a multi-width foil. Then the cut tab will carry the insulating layer 30, with higher efficiency.

[0034] It should be noted that the material area 11, the coating area 12, and the empty foil area 13 of the foil respectively correspond to different parts of the battery cell. Referring to Figure 5 , after cutting a single-width foil, multiple tabs are produced. The tab includes a part corresponding to the empty foil area 13 and a part provided with the insulating layer 30 and corresponding to the coating area 12. The tabs are evenly spaced along the length direction of the material area 11. Referring to Figure 6 , after cutting out the tabs, the single-width foil is then cut into two pole pieces. Referring to Figure 7, the electrode sheets are wound or laminated to form an electrode core, and multiple tabs can be connected by welding to form a tab group 40. It can be understood that the tab group 40 can include an insulating section 42 corresponding to the insulating layer 30, and also includes a connecting section 41 corresponding to the empty foil area 13. The connecting section 41 is used for welding to the connecting piece 60 of the battery, and the main body portion 50 of the electrode core corresponds to the material area 11. Among them, the connection between the tab group 40 of the electrode core and the connecting piece 60 is a key step in the battery assembly process, and the connecting piece 60 can ensure that the battery can be effectively connected to the external circuit.

[0035] Referring to Figure 3 and Figure 4 , as an embodiment, the coating area 12 includes a first coating area 122 and a second coating area 123 respectively located on both sides of the material area 11; the empty foil area 13 includes a first empty foil area 131 located away from the material area 11 in the first coating area 122, and the empty foil area 13 also includes a second empty foil area 132 located away from the material area 11 in the second coating area 123; the first empty foil area 131, the first coating area 122, the material area 11, the second coating area 123, and the second empty foil area 132 form a combined area; the foil includes multiple combined areas, and the multiple combined areas are arranged in sequence along the width direction of the foil, and the first empty foil area 131 of any one combined area is connected to the second empty foil area 132 of the adjacent combined area. According to this structure, the foil can be multiple sheets of foil.

[0036] As an embodiment, the widths of the first empty foil area 131 and the second empty foil area 132 are equal. Thus, when multiple sheets of foil are cut into multiple single sheets of foil, it can be cut at the connection between the first empty foil area 131 and the second empty foil area 132. Specifically, reference can be made to Figure 3 and Figure 4 for the cutting lines.

[0037] As an embodiment, there is a gap between the material layer 20 and the insulating layer 30. The setting of this gap can facilitate the subsequent folding of the tab group 40 of the battery. Specifically, in the field of battery production and manufacturing, after cutting out the tabs, the battery electrode sheets are formed into an electrode core by winding or other methods, and multiple tabs can be connected by welding to form a tab group 40, and then the entire electrode core will be placed in the battery housing. After the electrode core is put into the housing, the tab group 40 needs to be folded, and the folding position is between the insulating layer 30 and the material layer 20. Therefore, in this embodiment, there is a gap between the material layer 20 and the insulating layer 30, and this gap can be used as a folding line to facilitate the folding of the tab group 40. On the contrary, if the connection between the material layer 20 and the insulating layer 30 is too tight, or there is an overlapping area between the two, the tab group 40 will be too thick at the folding position, which is likely to cause difficulty in folding, obstacles during bending, or damage to the material layer 20 or the insulating layer 30 during folding.

[0038] As an embodiment, the thickness of the insulating layer 30 is between 10 μm and 20 μm. Thus, the setting of the thickness of the insulating layer 30 can effectively ensure the insulating performance of the insulating layer 30. On the contrary, if the thickness of the insulating layer 30 is less than 10 μm, the ability to prevent charge leakage is reduced, increasing the risk of short circuit. In addition, if the thickness of the insulating layer 30 is greater than 20 μm, the cost of battery production and manufacturing will increase. Therefore, considering the production cost and safety performance, the thickness of the insulating layer 30 can be set between 10 μm and 20 μm.

[0039] As an embodiment, the insulating layer 30 includes one of silicon dioxide nano powder, low density polyethylene, boehmite, and silicon nitride nano microspheres. The above materials all have good insulating properties. Specifically, the insulating layer can be connected to the coating area 12 by means of coating or deposition. Among them, the silicon dioxide nano powder can have excellent insulating properties, can effectively prevent the flow of charges, and has high thermal stability, and can maintain the insulating properties in a high temperature environment. Low density polyethylene has good electrical insulation properties and is also often used as the insulating layer for making wires and cables. It can effectively prevent the passage of current, and low density polyethylene also has good flexibility and heat resistance. Boehmite has high thermal stability and can maintain the insulating properties in a high temperature environment. Silicon nitride nano microspheres have good high temperature and corrosion resistance, and outstanding insulating properties. In addition, the insulating layer 30 can also include polyvinylidene fluoride or styrene-butadiene rubber, and include N-methylpyrrolidone or deionized water. Polyvinylidene fluoride or styrene-butadiene rubber can be used as a binder, and N-methylpyrrolidone or deionized water can be used as a solvent.

[0040] As an embodiment, the width of the material area 11 is greater than the total width of the coating area 12 and the empty foil area 13. Thus, the material area 11 is the main part 50 of the pole piece, and the coating area 12 and the empty foil area 13 are the pole ear parts of the pole piece. A larger width of the material area 11 can provide a larger contact area to ensure the efficiency of power transmission. The coating area 12 and the empty foil area 13 can provide sufficient length to connect with the connecting piece 60 of the battery, and only need to coat the insulating layer 30.

[0041] As an embodiment, the width of the empty foil area 13 is greater than or equal to the width of the coating area 12. Thus, in some examples, the empty foil area 13 can be as wide as the coating area 12, and in other examples, the empty foil area 13 is wider than the coating area 12. It can be understood that after the foil is made into a pole piece, both the empty foil area 13 and the coating area 12 are the pole ear parts of the pole piece, and the empty foil area 13 is used to connect the connecting piece 60 of the battery, and the coating area 12 is used to coat the insulating layer 30. Therefore, the width of the empty foil area 13 needs to ensure that there is enough area to connect with the connecting piece 60 as much as possible. Specifically, the width dimension of the empty foil area 13 can be set according to the specific model of the battery.

[0042] As an embodiment, the ratio of the width of the insulating layer 30 to the width of the empty foil area 13 is 0.5-1. Specifically, the ratio of the width of the empty foil area 13 to the width of the insulating layer 30 can be 0.5, 0.6, 0.7, 0.8, 1.

[0043] As an embodiment, the material of the base layer 10 is aluminum or copper. Specifically, according to the material used for the foil, the foil can be used as the positive electrode tab after cutting, or as the negative electrode tab. Among them, the foil with the base layer 10 made of aluminum material can be used as the positive electrode tab, and the tab cut from the positive electrode tab is the positive electrode tab. The foil with the base layer 10 made of copper material can be used as the negative electrode tab, and the tab cut from the negative electrode tab is the negative electrode tab.

[0044] As an embodiment, the material of the material layer 20 may include lithium iron phosphate, carbon nanotubes, polyvinylidene fluoride, and conductive carbon black. The above materials are mixed in proportion according to the battery manufacturing standard, and then coated on the material area 11 of the foil. The foil made in this way can be used as the positive electrode tab after cutting.

[0045] As another embodiment, the material of the material layer 20 includes: carbon, styrene-butadiene rubber, carboxymethyl cellulose, and conductive carbon black. The above materials are mixed in proportion according to the battery manufacturing standard, and then coated on the material area 11 of the foil. The foil made in this way can be used as the negative electrode tab after cutting.

[0046] Referring to Figure 6 , the second aspect of the present application provides a battery tab, which includes a foil for the battery, and the coating area 12 includes a plurality of spaced coating parts 121 arranged along the length direction of the material area 11, and the empty foil area 13 includes a plurality of spaced empty foil parts 133 arranged along the length direction of the material area 11; the plurality of empty foil parts 133 are arranged in one-to-one correspondence with the plurality of coating parts 121 and constitute the tabs of the battery tab.

[0047] Referring to Figure 5 , after a single foil is cut, a plurality of tabs are formed. The tabs include the empty foil part 133 and the coating part 121 provided with the insulating layer 30, and the tabs are evenly spaced along the length direction of the material area 11. Referring to Figure 6 , after cutting out the tabs, the single foil is cut into two tabs. Referring to Figure 7 , the tabs are wound or laminated to form an electrode core, and a plurality of tabs can be connected by welding to form a tab group 40. Referring to Figure 7 , the tab group 40 includes an insulating section 42 corresponding to the insulating layer 30, and also includes a connecting section 41 corresponding to the empty foil area 13. The connecting section 41 is used for welding to the connecting piece 60 of the battery, and the main body part 50 of the electrode core corresponds to the material area 11.

[0048] In some examples, adhesive tape can also be pasted on the surface of the insulating section 42 of the tab group 40. Thus, the stacked arrangement of the insulating layer 30 and the adhesive tape can achieve double insulation protection. Specifically, one side of the adhesive tape can be coated with adhesive, and the adhesive tape is pasted on the surface of the insulating section 42 through the adhesive. It can be understood that, in order to ensure the insulation performance, the adhesive tape can surround the insulating section 42 and completely cover the surface of the insulating section 42.

[0049] The third aspect of the present application also provides a battery, which includes battery electrode sheets in a rolled state.

[0050] In summary, for the foil used in the battery of the present application, the protective layer similar to the foil of the insulating layer 30 provided thereon can play a certain buffering role when the external machine cuts out the tabs, thereby reducing the probability of burrs generated when cutting the base layer 10, and the adhesion between the base layer 10 and the insulating layer 30 usually increases, which can also reduce the generation of burrs during the cutting process. In addition, when the tab of the battery cell is pasted with adhesive tape at a later stage, the risk of burrs piercing the adhesive tape can be reduced, and the adhesive tape and the insulating layer 30 are stacked, which can also provide double insulation protection for the tabs of the battery, further improving the safety performance of the battery.

[0051] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, the meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0052] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0053] The embodiments, implementation manners and related technical features of the present application can be combined and replaced with each other without conflict.

[0054] The above are only the preferred embodiments of the present application, and do not impose any form of limitation on the present application. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

[0055] Although the present utility model has been specifically described above in conjunction with the accompanying drawings and embodiments, it is understood that the above description does not limit the present utility model in any way. Those skilled in the art can make deformations and changes to the present utility model according to needs without departing from the essence and scope of the present utility model, and these deformations and changes all fall within the scope of the present utility model.

Claims

1. A foil for a battery, characterized in that, Comprising: A base layer, the base layer includes a material area, a coating area and an empty foil area arranged in parallel with each other, wherein, on both sides of the material area, there are respectively provided the coating areas, and on the side of the coating area away from the material area, there is provided the empty foil area; A material layer, the material layer is provided on the surface of the material area; An insulating layer, the insulating layer is provided on the surface of the coating area.

2. The foil for a battery according to claim 1, wherein There is a gap between the material layer and the insulating layer.

3. The foil for a battery according to claim 1, wherein The thickness of the insulating layer is between 10μm and 20μm.

4. The foil for a battery according to claim 1, characterized in that, The insulating layer includes: one of silicon dioxide nano powder, low density polyethylene, boehmite, silicon nitride nano microspheres.

5. The foil for a battery according to claim 1, wherein The width of the material area is greater than the total width of the coating area and the empty foil area.

6. The foil for a battery according to claim 1, characterized in that, The width of the empty foil area is greater than or equal to the width of the coating area.

7. The foil for a battery according to claim 1, characterized in that, The ratio of the width of the insulating layer to the width of the empty foil area is 0.5 - 1.

8. The foil for a battery according to claim 1, characterized in that, The coating area includes a first coating area and a second coating area respectively located on both sides of the material area; The empty foil area includes a first empty foil area located on the side of the first coating area away from the material area, and the empty foil area further includes a second empty foil area located on the side of the second coating area away from the material area; The first empty foil area, the first coating area, the material area, the second coating area and the second empty foil area form a combined area; The foil includes a plurality of the combined areas, the plurality of combined areas are arranged in sequence along the width direction of the foil, and the first empty foil area of any one of the combined areas is connected to the second empty foil area of the adjacent combined area.

9. The foil for a battery according to claim 8, characterized in that, The widths of the first empty foil area and the second empty foil area are equal.

10. A battery electrode plate, characterized in that, Including the foil for a battery according to any one of claims 1 - 7; The coating area includes a plurality of spaced - apart coating portions arranged along the length direction of the material area, and the empty foil area includes a plurality of spaced - apart empty foil portions arranged along the length direction of the material area; The plurality of empty foil portions and the plurality of coating portions are arranged in one - to - one correspondence and constitute the tabs of the battery electrode sheet.

11. A battery, characterized in that, Including the battery electrode sheet according to claim 10 in a rolled - up state.

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