Method for manufacturing bipolar battery and device for manufacturing bipolar battery

Abstract

Provided are a method for manufacturing a bipolar battery and a device for manufacturing a bipolar battery with which moisture contained in an electrode coating film can be optimized. A method for manufacturing a bipolar battery includes a dry environment maintenance step of maintaining a dry environment in a housing portion of a transport device that houses and transports a sheet having an electrode surface by dry air supplied by a dry air supply device. The dry environment maintenance step includes an adjustment step of adjusting an adjustment mechanism capable of adjusting at least one of an injection direction and an injection amount of the dry air injected relative to the electrode surface.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a bipolar battery and an apparatus for manufacturing a bipolar battery. Background Technology

[0002] Patent Document 1 discloses a technology for manufacturing an apparatus for reducing the entry of moisture into the interior of a sealed battery. In this manufacturing apparatus, in order to prevent moisture from adhering to the workpiece during the manufacturing process from the winding process to the sealing process, a dry air supply device for supplying dry air is provided inside multiple accommodating parts that respectively house the winding device, intermediate device, sealing device and conveyor line.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-139994 Summary of the Invention

[0004] In previous bipolar batteries operating in dry environments, there was a problem of differences in the evaporation of moisture contained in the coatings of the positive and negative electrodes.

[0005] However, in the aforementioned Patent Document 1, the dry air supply device only sets the interior of the housing as a dry environment, which cannot sufficiently reduce moisture adhesion, leading to deterioration of battery performance. There is room for improvement in the application of dry air to the electrode coating.

[0006] The present invention was made in view of the above, and its object is to provide a method for manufacturing a bipolar battery and an apparatus for manufacturing a bipolar battery that can optimize the amount of water contained in the electrode coating.

[0007] The method for manufacturing a bipolar battery according to the present invention includes the following steps: a dry environment maintenance step, wherein the receiving part of a conveying device that contains and conveys a sheet having an electrode surface is maintained in a dry environment by means of dry air supplied by a dry air supply device, wherein the dry environment maintenance step includes the following steps: an adjustment step, wherein an adjustment mechanism is adjusted to adjust at least one of the spray direction and the spray amount of the dry air sprayed relative to the electrode surface.

[0008] Furthermore, the bipolar battery manufacturing apparatus according to the present invention includes: a conveying device for conveying a sheet having an electrode surface; a receiving portion for receiving the conveying device; and a dry air supply device for supplying dry air into the receiving portion to maintain a dry environment inside the conveying device, wherein the dry air supply device includes: an adjustment mechanism capable of adjusting at least one of the spray direction and the spray amount of the dry air sprayed relative to the electrode surface.

[0009] Invention Effects

[0010] According to the present invention, the effect of optimizing the moisture contained in the electrode coating can be achieved. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 1 of the present invention.

[0012] Figure 2 This is a top view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 1 of the present invention.

[0013] Figure 3 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 2 of the present invention.

[0014] Figure 4 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 3 of the present invention.

[0015] Figure 5 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 4 of the present invention.

[0016] Figure 6 This is a top view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 4 of the present invention.

[0017] Figure 7 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for a bipolar battery according to Embodiment 5 of the present invention. Detailed Implementation

[0018] Hereinafter, a method for manufacturing a bipolar battery and an apparatus for manufacturing a bipolar battery according to embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the constituent elements in the following embodiments include elements that can be easily replaced by those skilled in the art or are substantially the same.

[0019] (Implementation Method 1)

[0020] [Simplified structure of a bipolar battery manufacturing apparatus]

[0021] Figure 1 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 1. Figure 2 This is a top view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 1. Figure 1 and Figure 2 The manufacturing apparatus 1 shown is an apparatus for producing a cylindrical wound electrode body 101 by winding a strip-shaped sheet 100 having electrodes around an axis. In this wound electrode body 101, a positive electrode is formed by coating a current collector layer on one side, and a negative electrode is formed by coating a current collector layer on the other side, thereby constituting a structure.

[0022] Furthermore, when the sheet 100 only has a positive electrode sheet, it has a positive electrode current collector foil made of aluminum foil and a positive electrode active material layer coated on a portion of the surface of the positive electrode current collector foil. The positive electrode active material layer includes a positive electrode active material, a conductive material made of acetylene black, and a binder. The positive electrode sheet has a portion coated with the positive electrode active material layer (i.e., a coated portion) and a portion uncoated (i.e., an uncoated portion).

[0023] Furthermore, when the sheet 100 only has a negative electrode sheet, it has a negative electrode current collector foil made of copper foil and a negative electrode active material layer coated on a portion of the surface of the negative electrode current collector foil. This negative electrode active material layer includes a negative electrode active material, SBR (binder), and CMC (thickener). The negative electrode sheet also has a portion coated with the negative electrode active material layer (the coated portion) and a portion not coated with the negative electrode active material layer (the uncoated portion).

[0024] Furthermore, a separator can be inserted between the sheet 100 (positive electrode) and the sheet 100 (negative electrode) to fabricate the wound electrode body 101. In this case, a separator made of an electrically insulating resin film can be used. This separator is inserted between the positive and negative electrode sheets to separate them. The separator is impregnated with a non-aqueous electrolyte containing lithium ions.

[0025] The manufacturing apparatus 1 includes at least: a winding device 2, which functions as a conveying device for conveying the sheet 100; a receiving section 3, which receives the winding device 2; and a dry air supply device 4, which supplies dry air to the receiving section 3.

[0026] The winding device 2 is constructed using a known winding machine. The winding device 2 has multiple rollers 20 to 25 that wind the sheet 100 around an axis to form a cylindrical winding electrode body 101.

[0027] The receiving section 3 houses the winding device 2 within the interior K1. The receiving section 3 is formed from a wall portion using resin (e.g., PET). The receiving section 3 is supplied with dry air DA from the dry air supply device 4. Here, the dry air DA is dry air with a dew point below -30°C.

[0028] The dry air supply device 4 supplies dry air to the housing 3 via pipe 41, maintaining the interior of the housing 3 in a dry environment (dry environment maintenance process). The dry air supply device 4 has an adjustment mechanism 42 capable of adjusting at least one of the spray direction and spray amount of dry air relative to the electrode surface in the sheet 100.

[0029] Specifically, such as Figure 2As shown, the dry air supply device 4 has an adjustment mechanism 42, which has multiple injection ports located at the upper and lower parts of the receiving portion 3. The adjustment mechanism 42 is constructed, for example, using a rectifier plate, a fan, and an injection adjustment valve. Figure 1 and Figure 2 In the case shown, the adjusting mechanism 42 adjusts the dry air injected by the adjusting mechanism 42 so that the airflow of the dry air DA injected from the upper side of the electrode surface (the surface of the sheet 100) is greater than the airflow of the dry air DA injected from the lower side of the electrode surface (the back side of the sheet 100). Of course, the ratio of the airflow of the upper and lower sides of the dry air injected by the adjusting mechanism 42 to the electrode can be appropriately adjusted, for example, within the range of 0 to 100%.

[0030] Furthermore, the dry air supply device 4 is adjusted such that the airflow of the dry air on the upper side gradually increases according to the conveying direction A1 of the sheet 100. In addition, the dry air supply device 4 can separate the receiving section 3 into each specified area (e.g., each section or each process) and adjust the amount of dry air injected from the upper side using dampers or the like installed in the duct 41.

[0031] The manufacturing apparatus 1 configured in this way performs a drying environment maintenance process, maintaining the container 3 in a dry environment of dry air DA, and simultaneously performing a coating process, a pressurization process, a baking process and a battery process in the container 3, thereby manufacturing a bipolar battery.

[0032] The coating process involves thinly and uniformly coating a mixture of powdered materials and liquid slurry (positive or negative electrode active material) mixed in a mixer onto the surface of a metal foil (aluminum foil) or a negative electrode sheet (copper foil). Here, the slurry is a solid-liquid suspension uniformly dispersed by mixing active material, conductive carbon, thickener, binder, additives, solvent, etc., in a mixer in a specific ratio.

[0033] The pressing process involves applying pressure to the coated positive electrode sheet (aluminum foil) or negative electrode sheet (copper foil) using rollers or similar methods to compress it to the target thickness. The baking process involves drying the coated positive electrode sheet or negative electrode sheet after the pressing process to remove the solvent, allowing the fixing material to adhere to the sheet (substrate) to form the positive electrode sheet or negative electrode sheet.

[0034] The battery process is a process of making a cylindrical wound electrode body by winding the positive electrode, negative electrode and separator around an axis in an overlapping manner after the baking process.

[0035] Thus, during the drying environment maintenance process in manufacturing apparatus 1, the drying air supply device 4 supplies drying air DA to the receiving section 3 via the adjustment mechanism 42. Simultaneously, in each of the coating, pressurizing, baking, and battery-making processes, the drying air DA is sprayed while adjusting at least one of the spray direction and spray amount of the drying air relative to the electrode surface in the sheet 100. This optimizes the moisture content contained in the electrode coating of the sheet 100. Furthermore, in Embodiment 1, an example of performing the coating, pressurizing, baking, and battery-making processes within the receiving section 3 has been described, but this is not a limitation; other devices may also be used to perform these processes.

[0036] According to Embodiment 1 described above, the dry air supply device 4 performs an adjustment process in the dry environment maintenance process. The adjustment process adjusts the adjustment mechanism 42, which can adjust at least one of the spray direction and spray amount of the dry air relative to the electrode surface in the sheet 100, thereby optimizing the moisture contained in the electrode coating (electrode surface) of the sheet 100.

[0037] (Implementation Method 2)

[0038] Next, implementation method 2 will be described. Figure 3 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 2.

[0039] Figure 3 The bipolar battery manufacturing apparatus 1A shown has the same structure as the manufacturing apparatus 1 according to Embodiment 1, but the spray direction of the dry air DA supplied by the dry air supply device 4 is different. Specifically, the dry air supply device 4 sprays dry air DA only onto the upper side of the electrode surface coated on the upper surface of the sheet 100. For example, relative to the electrode surface coated on the upper surface of the sheet 100, the dry air supply device 4 sprays dry air DA only upwards in a manner that applies it from the side of the coating film where moisture is not easily volatile. In particular, in sheet 100 with a structure in which other coating films are applied to the electrode surfaces sandwiching bipolar electrodes, the non-volatileness varies depending on the type of coating film. By applying dry air DA from the non-volatile coating film, it is possible to suppress moisture adhesion to the remaining electrodes.

[0040] According to Embodiment 2 described above, the dry air supply device 4 sprays dry air DA only onto the upper side of the coating film on the electrode surface coated on the upper surface of the sheet 100. Therefore, by applying the dry air DA from the non-volatile coating film, it is possible to suppress the adhesion of moisture to the remaining electrode surface.

[0041] (Implementation Method 3)

[0042] Next, implementation method 3 will be described. Figure 4This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 3.

[0043] Figure 4 The bipolar battery manufacturing apparatus 1B shown has the same structure as the manufacturing apparatus 1 according to Embodiment 1. The dry air supplied by the dry air supply device 4 is sprayed at an angle relative to the conveying direction A1 of the sheet 100. Furthermore, the dry air supply device 4 sprays more of the upper side of the dry air DA onto the sheet 100 than the lower side of the receiving portion 3. In addition, the ratio of the air volume of the upper and lower sides of the dry air DA sprayed onto the electrode by the adjusting mechanism 42 can be appropriately adjusted, for example, within the range of 0 to 100%.

[0044] According to Embodiment 3 described above, the dry air supply device 4 performs an adjustment process in the drying environment maintenance process. The adjustment process adjusts the adjustment mechanism 42, which can adjust at least one of the spray direction and spray amount of the dry air relative to the electrode surface in the sheet 100, thereby optimizing the moisture contained in the electrode coating (electrode surface) of the sheet 100.

[0045] (Implementation Method 4)

[0046] Next, implementation method 4 will be described. Figure 5 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 4. Figure 6 This is a top view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 4.

[0047] Figure 5 and Figure 6 The bipolar battery manufacturing apparatus 1C shown includes, in addition to the structure of the manufacturing apparatus 1 of Embodiment 1 described above, a moisture removal device 5 for removing moisture from the dry air DA.

[0048] The moisture removal device 5 is connected to the pipe 41, which supplies dry air DA via the pipe 51. It sprays dry air DA containing trace amounts of moisture from the upper side of the container 3. Furthermore, the moisture removal device 5 regenerates the dry air DA recovered from the container 3 according to the dew point, turns it into low dew point dry air DA, and supplies it to the pipe 41, so that the dry air DA is circulated.

[0049] In addition, in the manufacturing apparatus 1C, various sensors such as humidity sensors or temperature sensors can be installed in the pipe 51. Based on the detection results of these various sensors, the opening and closing of the valve 52 installed in the pipe 51 is controlled, thereby adjusting the moisture content of the dry air DA circulating in the dry air supply device 4.

[0050] According to Embodiment 4 described above, the moisture removal device 5 recovers dry air DA containing trace amounts of moisture, and produces low-dew-point dry air DA based on the dry air DA recovered by dew point regeneration and supplies it to pipe 41, thus enabling the dry air DA to circulate.

[0051] (Implementation Method 5)

[0052] Next, implementation method 5 will be described. Figure 7 This is a cross-sectional view showing the schematic structure of the manufacturing apparatus for the bipolar battery according to Embodiment 5.

[0053] Figure 7 In addition to the structure of Embodiment 1, the bipolar battery manufacturing apparatus 1D shown also includes a gate 6 within the housing 3 that separates the area H1, where the replacement operation of the winding electrode body 101, such as the roller supplying the sheet 100, is performed, from other areas H2. Therefore, even when the operator is changing the roller and entering area H1, the manufacturing apparatus 1D can maintain the dew point of the dry air DA in the management area H2 because the gate 6 separates area H2 from the space.

[0054] According to Embodiment 5 described above, by providing a gate 6 in the receiving section 3 to separate the area H1, where the replacement operation of the winding electrode 101 such as the roller that supplies the sheet 100 is performed, from other areas H2, it is possible to maintain the dew point of the dry air DA in the management area H2.

[0055] Further effects or variations can be readily derived by those skilled in the art. Therefore, the invention is presented in a broader manner as described above and is not limited to the specific details and representative embodiments described above. Thus, various modifications can be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

[0056] Symbol Explanation

[0057] 1, 1A, 1B, 1C, 1D - Manufacturing apparatus; 2 - Winding apparatus; 3 - Receiving part; 4 - Dry air supply device; 5 - Moisture removal device; 6 - Gate; 20-25 - Rollers; 41, 51 - Pipelines; 42 - Adjustment mechanism; 52 - Valve; 100 - Sheet; 101 - Winding electrode body; DA - Dry air; H1 - Area; H2 - Area; K1 - Interior.

Claims

1. A method for manufacturing a bipolar battery, characterized in that, It has the following processes: The drying environment maintenance process maintains a dry environment within the containment of the conveyor holding the sheet with the electrode surface by means of dry air supplied by the dry air supply device. The process of maintaining a dry environment includes the following steps: The adjustment process involves adjusting a mechanism capable of adjusting at least one of the injection direction and injection quantity of the dry air sprayed relative to the electrode surface.

2. The method for manufacturing a bipolar battery according to claim 1, characterized in that, The adjustment mechanism has: Multiple injection nozzles are provided within the conveying device along the conveying direction of the sheet. The adjustment process is performed as follows: The flow rate of the dry air from the nozzle is gradually increased along the conveying direction of the sheet, within each specified interval.

3. The method for manufacturing a bipolar battery according to claim 1, characterized in that, The adjustment mechanism has: Multiple injection nozzles are arranged vertically within the conveying device along the conveying direction of the sheet. The adjustment process is performed as follows: The amount of dry air injected from the upper nozzle is adjusted to be greater than the amount of dry air injected from the lower nozzle.

4. The method for manufacturing a bipolar battery according to claim 1, characterized in that, The adjustment process involves the following steps: The dry air is sprayed in an inclined direction toward the conveying direction of the sheet.

5. An apparatus for manufacturing a bipolar battery, characterized in that, have: A conveying device for conveying sheets having electrode surfaces; A receiving section that houses the conveying device; and A dry air supply device supplies dry air into the receiving section to maintain a dry environment within the conveying device. The dry air supply device has: An adjustment mechanism is provided that can adjust at least one of the injection direction and injection quantity of the dry air sprayed relative to the electrode surface.

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