Pole piece manufacturing method

Abstract

The invention discloses a pole piece manufacturing method, which is a semi-dry method and comprises the following steps of: spraying a small amount of special glue on a battery base band, and uniformly scattering mixed powder of an active substance and an additive on a base material of a pole piece through a quantitative powder feeding device; the wet method comprises the following steps: uniformly coating the mixed slurry of the active substance, the additive and the solvent on the base material through a quantitative slurry feeding device; and preliminarily pressing the mixed powder which is quantitatively loaded on the base material into the base material through a movable flat plate press. According to the pole piece manufacturing method disclosed by the invention, the pole piece is manufactured by adopting a semi-dry method active quantitative feeding mode, so that the density of active substances in the pole piece is relatively high, the pole piece is relatively soft, the active substances are not easy to fall off, and the quality of the active substances in a unit area on a base material is ensured to be consistent, so that the consistency of battery performance is achieved; in the same way, the pole piece can be manufactured by adopting a wet-process active quantitative feeding mode.

Description

Technical Field

[0001] The present invention relates to the technical field of battery manufacturing, and particularly to a method for manufacturing an electrode sheet. Background Art

[0002] With the rapid development of China's new energy energy storage industry and electric vehicles, it has greatly promoted the rapid growth of China's battery production. In 2024 alone, the cumulative sales volume of China's batteries reached 1,039.5 GWh, with a cumulative year-on-year growth of 42.4%. At the same time, the performance requirements for batteries (especially consistency, long life, high rate, etc.) are also getting higher and higher.

[0003] A battery generally consists of five major parts: a positive electrode sheet, a negative electrode sheet, a separator, an electrolyte, and a casing. Among them, the electrode sheet is the most critical. The battery electrode sheet is prepared by adhering or filling active substances on a baseband. The baseband has three-dimensional and two-dimensional, both of which are metal conductive materials. The production methods of electrode sheets are divided into two types: wet method and dry method. The wet method is to coat a slurry mixture of active substances, additives (such as binders, conductive agents, etc.) and solvents on the battery baseband through a slitting die or a spraying device, and then make the battery electrode sheet through drying, rolling, and cutting.

[0004] Existing battery manufacturing has certain drawbacks in use. The disadvantage of the wet method is that the compaction density of the active substances in the electrode sheet is relatively low, the proportion of the binder is relatively high, the utilization rate of the active substances is relatively low, the charge-discharge rate is relatively low, and drying equipment is required, resulting in high power consumption and a relatively long electrode sheet production line. The dry method is to directly press a mixed powder of active substances and additives on the battery baseband through a powder brushing device or by a rolling and pressing method, and then make the battery electrode sheet through rolling and cutting. The disadvantage of the dry method is that the rolling requirements are relatively high, the active substances are easily detached, which is likely to cause battery short circuits, and the cycle life is relatively short. Both of these two electrode sheet manufacturing methods have a common weakness, that is, they are both passive feeding onto the substrate, which makes it difficult to ensure that the feeding amount per unit area of each electrode sheet is exactly the same, thus unable to ensure the consistency of battery performance. Since the vast majority of actual applications do not use a single battery, but use battery packs composed of series and parallel connections, if the consistency of single cells cannot be ensured, the life of the battery pack will be significantly reduced. Therefore, we propose a method for manufacturing an electrode sheet. Summary of the Invention

[0005] Technical problems to be solved: Aiming at the deficiencies of the prior art, the present invention provides a method for manufacturing an electrode sheet, which uses a semi-dry method of active quantitative feeding to manufacture the electrode sheet, so as to achieve a relatively high density of active substances in the electrode sheet, and the electrode sheet is relatively soft, the active substances are not easily detached, and the amount of active substances per unit area on the substrate is ensured to be consistent, thereby achieving the consistency of battery performance and improving the service life of the battery pack. Similarly, the electrode sheet can also be manufactured by using a wet method of active quantitative feeding, which can effectively solve the problems in the background art.

[0006] Technical solution: To achieve the above object, the technical solution adopted by the present invention is as follows: A method for manufacturing a pole piece mainly includes the following operating steps: S1: Semi-dry method: First, a small amount of special glue is added to the battery base tape by one of spraying, brushing, and coating, and then the mixed powder of the active material and the additive is evenly scattered on the base material of the pole piece through a quantitative powder feeding device; S2: Wet method: The mixed slurry of the active material, the additive, and the solvent is evenly coated on the base material through a quantitative slurry feeding device; S3: The mixed powder and the mixed slurry quantitatively fed onto the base material are preliminarily pressed into the base material by a mobile flat press, and then the pole piece is compacted by a fixed flat press and a rolling method; S4: The pole piece is manufactured by the semi-dry active quantitative feeding method to achieve a relatively high density of the active material in the pole piece, and the pole piece is relatively soft, the active material is not easily detached, and the amount of the active material per unit area on the base material is ensured to be consistent, so as to achieve the consistency of the battery performance and improve the service life of the battery pack; S5: The pole piece is manufactured by the wet active quantitative feeding method, which can ensure the consistency of the amount of the active material per unit area on the base material, so as to achieve the consistency of the battery performance and improve the service life of the battery pack.

[0007] As a preferred technical solution of the present application, the glue contains a solvent, and the solvent is water, ethanol, N-methylpyrrolidone, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, isoparaffinic solvent oil, and can be a mixed solvent of one or several of them.

[0008] As a preferred technical solution of the present application, the glue contains an adhesive, the adhesive is sodium carboxymethyl cellulose, sodium hydroxypropyl cellulose, methyl cellulose, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, silver glue, polyvinylidene fluoride, polymethyl methacrylate, and can be a mixed adhesive of one or several of them. The weight ratio of the solvent to the adhesive is 100:0.01 - 30.

[0009] As a preferred technical solution of the present application, the glue further includes a conductive agent, the conductive agent is carbon powder, acetylene black, graphite, nickel powder, nickel fiber, cobalt powder, silver powder, cobaltous oxide, cobalt hydroxide, and the weight ratio of the solvent, the adhesive, and the conductive agent is 100:0.01 - 30:0.01 - 15.

[0010] As a preferred technical solution of the present application, the three dimensions of the battery base tape in the S1 step include foamed nickel, foamed copper, foamed iron, and fiber nickel.

[0011] As a preferred technical solution of the present application, in the S1 step, the two-dimensional battery baseband includes nickel-plated perforated steel strip, perforated nickel strip, perforated copper strip, perforated aluminum strip, perforated steel strip, nickel mesh, steel mesh, copper mesh, copper strip, aluminum strip and steel strip.

[0012] As a preferred technical solution of the present application, in the S1-S5 steps, the pole pieces are made by semi-dry active quantitative feeding and wet active quantitative feeding methods respectively.

[0013] Beneficial effects: Compared with the prior art, the present invention provides a method for manufacturing a pole piece, which has the following beneficial effects: This method for manufacturing a pole piece uses the semi-dry active quantitative feeding method to manufacture the pole piece, so as to achieve a relatively high density of active substances in the pole piece, and the pole piece is relatively soft, the active substances are not easy to fall off, and the amount of active substances per unit area on the substrate is ensured to be consistent, thereby achieving the consistency of battery performance and improving the service life of the battery pack. Similarly, the wet active quantitative feeding method can also be used to manufacture the pole piece. Semi-dry method: First, a small amount of special glue is added to the battery baseband by one of spraying, brushing and coating, and then the mixed powder of active substances and additives is evenly scattered on the substrate of the pole piece through a quantitative powder feeding device; the mixed slurry of active substances, additives and solvent is evenly coated on the substrate through a quantitative slurry feeding device; the semi-dry active quantitative feeding method is used to manufacture the pole piece, so as to achieve a relatively high density of active substances in the pole piece, and the pole piece is relatively soft, the active substances are not easy to fall off, and the amount of active substances per unit area on the substrate is ensured to be consistent, thereby achieving the consistency of battery performance and improving the service life of the battery pack; using the wet active quantitative feeding method to manufacture the pole piece can ensure the consistency of the amount of active substances per unit area on the substrate, thereby achieving the consistency of battery performance and improving the service life of the battery pack. The entire pole piece manufacturing structure is simple, easy to operate, and the use effect is better than the traditional method. Description of the Drawings

[0014] Figure 1 It is a schematic process flow diagram of the semi-dry production of a method for manufacturing a pole piece according to the present invention.

[0015] Figure 2 It is a schematic structural diagram of the wet production process flow in a method for manufacturing a pole piece according to the present invention.

[0016] Figure 3 It is a schematic diagram of the original data of the positive pole piece and the battery in a method for manufacturing a pole piece according to the present invention.

[0017] Figure 4 It is the first thickness measurement diagram of the positive pole piece in a method for manufacturing a pole piece according to the present invention.

[0018] Figure 5 It is the second thickness measurement diagram of the positive pole piece in a method for manufacturing a pole piece according to the present invention.

[0019] Figure 6 This is the first of the positive electrode sheet weight measurement diagrams in a method for manufacturing an electrode sheet according to the present invention.

[0020] Figure 7 This is the second of the positive electrode sheet weight measurement diagrams in a method for manufacturing an electrode sheet according to the present invention.

[0021] Figure 8 This is the first of the battery capacity measurement diagrams in a method for manufacturing an electrode sheet according to the present invention.

[0022] Figure 9 This is the second of the battery capacity measurement diagrams in a method for manufacturing an electrode sheet according to the present invention. Detailed implementation manners

[0023] The technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific implementation manners. However, those skilled in the art will understand that the following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0024] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" 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 directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0026] As Figures 1-9 shown, a method for manufacturing an electrode sheet mainly includes the following operation steps: S1: Semi-dry method: First, apply a small amount of special glue on the battery base tape by one of spraying, brushing, and coating, and then evenly sprinkle the mixed powder of active material and additive on the substrate of the electrode plate through a metering powder feeding device; S2: Wet method: Evenly coat the mixed slurry of active material, additive, and solvent on the substrate through a metering slurry feeding device; S3: Use a mobile flat press to initially press the mixed powder and mixed slurry fed in a fixed quantity on the substrate into the substrate, and then compact the electrode plate by a fixed flat press and a rolling method; S4: Use the semi-dry active metering feeding method to manufacture the electrode plate, so as to achieve a higher density of active material in the electrode plate, and the electrode plate is softer, the active material is not easy to fall off, and ensure that the amount of active material per unit area on the substrate is consistent, so as to achieve the consistency of battery performance and improve the service life of the battery pack; S5: Use the wet active metering feeding method to manufacture the electrode plate, which can ensure that the amount of active material per unit area on the substrate is consistent, so as to achieve the consistency of battery performance and improve the service life of the battery pack.

[0027] Furthermore, the glue contains a solvent, and the solvent is water, ethanol, N-methylpyrrolidone, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, isoparaffinic solvent oil, and can be a mixed solvent of one or several of them.

[0028] Furthermore, the glue contains an adhesive, and the adhesive is sodium carboxymethyl cellulose, sodium hydroxypropyl cellulose, methyl cellulose, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, silver glue, polyvinylidene fluoride, polymethyl methacrylate, and can be a mixed adhesive of one or several of them. The weight ratio of the solvent to the adhesive is 100:0.01 - 30.

[0029] Furthermore, the glue also includes a conductive agent, and the conductive agent is carbon powder, acetylene black, graphite, nickel powder, nickel fiber, cobalt powder, silver powder, cobaltous oxide, cobalt hydroxide. The weight ratio of the solvent, adhesive, and conductive agent is 100:0.01 - 30:0.01 - 15.

[0030] Furthermore, in step S1, the three-dimensional battery base tape includes foamed nickel, foamed copper, foamed iron, and fiber nickel.

[0031] Furthermore, in step S1, the two-dimensional battery base tape includes nickel-plated perforated steel strip, perforated nickel strip, perforated copper strip, perforated aluminum strip, perforated steel strip, nickel mesh, steel mesh, copper mesh, copper strip, aluminum strip, and steel strip.

[0032] Furthermore, in steps S1 - S5, the electrode plates are manufactured by the semi-dry active metering feeding method and the wet active metering feeding method respectively. Example 1:

[0033] According to the innovative semi-dry production process flow, a special glue is sprayed on the positive electrode substrate, and the substrate is foamed nickel. The glue is composed of 1 kg of 20% alcohol (a mixture of water and ethanol), 0.5 kg of polytetrafluoroethylene emulsion with a concentration of 60%. Then, the mixed powder of active substances and additives is scattered on the foamed nickel of the electrode through a quantitative feeding device. After pre-pressing by a mobile flat press, the electrode is then compacted by a fixed flat press or a rolling method, and then cut to make a battery positive electrode, and finally assembled with a negative electrode produced by the traditional method to form a battery. Example 2:

[0034] According to the innovative wet production process flow, a special glue is sprayed on the positive electrode substrate, and the substrate is foamed nickel. The glue is composed of 1 kg of 20% alcohol (a mixture of water and ethanol), 0.5 kg of polytetrafluoroethylene emulsion with a concentration of 60%. Then, the mixed powder of active substances and additives is scattered on the foamed nickel of the electrode through a quantitative feeding device. After pre-pressing by a mobile flat press, the electrode is then compacted by a fixed flat press or a rolling method, and then cut to make a battery positive electrode, and finally assembled with a negative electrode produced by the traditional method to form a battery. Example 3:

[0035] According to the innovative semi-dry production process flow, a special glue is sprayed on the positive electrode substrate, and the substrate is foamed nickel. The glue is composed of 1 kg of water, 0.5 kg of polytetrafluoroethylene emulsion with a concentration of 60%, 1.5 g of sodium carboxymethylcellulose, and 1.5 g of ultrafine carbon powder. Then, the mixed powder of active substances and additives is scattered on the foamed nickel of the electrode through a quantitative feeding device, and then rolled, and finally cut to make a battery positive electrode, and finally assembled with a negative electrode produced by the traditional method to form a battery.

[0036] As Figures 3-9 shown, it can be seen from the test data that for the electrodes made by the active quantitative feeding method, whether in terms of thickness, weight, and the battery capacity distribution made therefrom is relatively narrow, which is significantly better than the electrodes made by the traditional passive feeding method and the batteries supported thereby. The negative electrode capacity in the battery is generally greater than the positive electrode capacity. Therefore, the capacity of the battery is determined by the capacity of the positive electrode, and the capacity of the positive electrode is determined by the amount of active substances in the positive electrode.

[0037] It should be noted that in this article, relational terms such as first and second (No. 1, No. 2), etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0038] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A method for manufacturing a pole piece, characterized in that: The main steps are as follows: S1: Semi-dry method: first add a small amount of special glue to the battery base tape by spraying, brushing or coating, and then evenly sprinkle the mixed powder of active material and additives on the base material of the pole piece through a quantitative powder feeding device; S2: Wet method: The mixed slurry of active substance, additive and solvent is evenly coated on the substrate through a quantitative slurry feeding device; S3: Preliminarily press the mixed powder and mixed slurry quantitatively loaded on the substrate onto the substrate by a mobile flat plate press, and then compact the pole piece by a fixed flat plate press and rolling; S4: The pole piece is made by using a semi-dry active quantitative feeding method to achieve a higher density of active materials in the pole piece, and the pole piece is relatively soft, the active material is not easy to fall off, and the mass of active materials per unit area on the substrate is ensured to be consistent, thereby achieving consistency of battery performance and improving the service life of the battery pack; S5: The electrode is made by wet active quantitative loading method, which can ensure the consistency of the active material mass per unit area on the substrate, thereby achieving consistency in battery performance and improving the service life of the battery pack.

2. A method for manufacturing a pole piece according to claim 1, characterized in that: The glue contains a solvent, and the solvent is water, ethanol, N-methyl pyrrolidone, dipropylene glycol dimethyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, isoparaffin solvent oil, and can be one or a mixed solvent of several of them.

3. A method for manufacturing a pole piece according to claim 1, characterized in that: The glue contains an adhesive, which is sodium carboxymethyl cellulose, sodium hydroxypropyl cellulose, methyl cellulose, styrene-butadiene rubber, polyvinyl alcohol, polytetrafluoroethylene, silver glue, polyvinylidene fluoride, polymethyl methacrylate, or a mixed adhesive of one or more thereof. The weight ratio of the solvent to the adhesive is 100:0.01-30.

4. A method for manufacturing a pole piece according to claim 1, characterized in that: The glue also includes a conductive agent, which is carbon powder, acetylene black, graphite, nickel powder, nickel fiber, cobalt powder, silver powder, cobaltous oxide, and cobalt hydroxide. The weight ratio of the solvent, the adhesive, and the conductive agent is 100:0.01-30:0.01-15.

5. A method for manufacturing a pole piece according to claim 1, characterized in that: In the step S1, the three-dimensional battery base strip includes foamed nickel, foamed copper, foamed iron, and fiber nickel.

6. A method for manufacturing a pole piece according to claim 1, characterized in that: In the step S1, the two-dimensional battery base strip includes nickel-plated porous steel strip, porous nickel strip, porous copper strip, porous aluminum strip, porous steel strip, nickel mesh, steel mesh, copper mesh, copper strip, aluminum strip and steel strip.

7. A method for manufacturing a pole piece according to claim 1, characterized in that: In the steps S1 to S5, the pole pieces are manufactured by using a semi-dry active quantitative loading method and a wet active quantitative loading method respectively.

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