Method for manufacturing a bipolar battery and apparatus for manufacturing a bipolar battery

Abstract

The present invention provides a method for manufacturing a bipolar battery and an apparatus for manufacturing a bipolar battery that can optimize the moisture content of the electrode coating film. [Solution] The method for manufacturing a bipolar battery includes a dry environment maintenance step in which a dry air supply device 4 supplies dry air DA to maintain a dry environment inside a housing section 3 that houses a transport device for transporting a sheet 100 having an electrode surface. The dry environment maintenance step includes an adjustment step of adjusting an adjustment mechanism that can adjust at least one of the injection direction and injection amount of dry air DA injected onto the electrode surface.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a bipolar battery and a manufacturing apparatus for a bipolar battery.

Background Art

[0002] Patent Document 1 discloses a technique for a manufacturing apparatus for a sealed battery that reduces the entry of moisture into the sealed battery. In this manufacturing apparatus, in order to prevent moisture from adhering to the workpiece in the manufacturing process from the winding process to the sealing process, a dry air supply device for supplying dry air is provided inside a plurality of accommodating portions that accommodate the winding device, the intermediate device, the sealing device, and the conveyance line, respectively.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a conventional bipolar battery in a dry environment, there has been a problem that there is a difference in the volatilization of moisture contained in each coating film of the positive electrode and the negative electrode.

[0005] However, in Patent Document 1 described above, the inside of the accommodating portion is only made into a dry environment by the dry air supply device, and moisture adhesion cannot be sufficiently reduced, leading to deterioration of battery performance, and there is room for improvement in the way of applying dry air to the electrode coating film.

[0006] The present disclosure has been made in view of the above, and an object thereof is to provide a method for manufacturing a bipolar battery and a manufacturing apparatus for a bipolar battery that can optimize the moisture contained in the electrode coating film.

Means for Solving the Problems

[0007] The method for manufacturing a bipolar battery according to the present disclosure is a method for manufacturing a bipolar battery, comprising a dry environment maintenance step of maintaining a dry environment inside a housing that houses a conveying device for conveying a sheet having an electrode surface, using dry air supplied by a dry air supply device, wherein the dry environment maintenance step includes an adjustment step of adjusting an adjustment mechanism capable of adjusting at least one of the injection direction and injection amount of the dry air injected onto the electrode surface.

[0008] Furthermore, the manufacturing apparatus for a bipolar battery according to this disclosure comprises a conveying device for conveying a sheet having an electrode surface, a housing for housing the conveying device, and a dry air supply device for supplying dry air into the housing to maintain a dry environment inside the conveying equipment, wherein the dry air supply device has an adjustment mechanism that can adjust at least one of the injection direction and injection amount of the dry air injected onto the electrode surface. [Effects of the Invention]

[0009] According to this disclosure, the effect is that the moisture content in the electrode coating can be optimized. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view showing a schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 1 of the present disclosure. [Figure 2] Figure 2 is a top view showing a schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 1 of this disclosure. [Figure 3] Figure 3 is a cross-sectional view showing a schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 2 of this disclosure. [Figure 4] Figure 4 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 3 of this disclosure. [Figure 5] Figure 5 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 4 of the present disclosure. [Figure 6]Figure 6 is a top view showing a schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 4 of the present disclosure. [Figure 7] Figure 7 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 5 of the present disclosure. [Modes for carrying out the invention]

[0011] Hereinafter, a method for manufacturing a bipolar battery and a manufacturing apparatus for a bipolar battery according to embodiments of this disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily substituted or substantially identical to those that are easily substituted by a person skilled in the art.

[0012] (Embodiment 1) [Outline configuration of a bipolar battery manufacturing apparatus] Figure 1 is a cross-sectional view showing the schematic configuration of a manufacturing apparatus for a bipolar battery according to Embodiment 1. Figure 2 is a top view showing the schematic configuration of a manufacturing apparatus for a bipolar battery according to Embodiment 1. The manufacturing apparatus 1 shown in Figures 1 and 2 is an apparatus that creates a cylindrical wound electrode body 101 by winding a strip-shaped sheet 100 having electrodes around its axis. This wound electrode body 101 is formed by coating a positive electrode current collector layer on one side and a negative electrode current collector layer on the other side.

[0013] Furthermore, in the case of a positive electrode sheet only, sheet 100 has a positive electrode current collector foil made of aluminum foil and a positive electrode active material layer coated on a part of the surface of the positive electrode current collector foil. The positive electrode active material layer also includes a positive electrode active material, a conductive material made of acetylene black, and a binder. The positive electrode sheet also has a positive electrode active material layer coated portion, which is the part where the positive electrode active material layer is coated, and a positive electrode active material layer uncoated portion, which is the part where the positive electrode active material layer is not coated.

[0014] Further, when the sheet 100 is only a negative electrode sheet, it has a negative electrode current collector foil made of a copper foil, and a negative electrode active material layer coated on a part of the surface of the negative electrode current collector foil. This negative electrode active material layer contains a negative electrode active material, SBR (binder), and CMC (thickener). Further, the negative electrode sheet has a negative electrode active material layer coating part where the negative electrode active material layer is coated, and a negative electrode active material layer non - coating part where the negative electrode active material layer is not coated.

[0015] Also, a wound electrode body 101 can be created by interposing a separator between the sheet 100 (positive electrode sheet) and the sheet 100 (negative electrode sheet). In this case, as the separator, a separator made of a resin film having electrical insulation can be used. This separator is interposed between the positive electrode sheet and the negative electrode sheet to separate them. This separator is impregnated with a non - aqueous electrolyte having lithium ions.

[0016] The manufacturing apparatus 1 includes at least a winding device 2 that functions as a conveying device for conveying the sheet 100, a housing part 3 that houses the winding device 2, and a dry air supply device 4 that supplies dry air to the housing part 3.

[0017] The winding device 2 is configured using a known winding machine. The winding device 2 has a number of rollers 20 - 25, and winds the sheet 100 around an axis to produce a cylindrical wound electrode body 101.

[0018] The housing part 3 houses the winding device 2 inside K1. The housing part 3 is formed with a wall part made of a resin (for example, PET). The housing part 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 of - 30°C or lower.

[0019] The dry air supply device 4 supplies dry air to the housing part 3 via a duct 41 and maintains the inside of the housing part 3 in a dry environment (dry environment maintenance process). The dry air supply device 4 has an adjustment mechanism 42 that can adjust at least one of the injection direction and injection amount of the dry air with respect to the electrode surface of the sheet 100.

[0020] Specifically, as shown in FIG. 2, the dry air supply device 4 has an adjustment mechanism 42 having a plurality of injection ports provided in the upper and lower portions of the housing portion 3. The adjustment mechanism 42 is configured using, for example, a rectifying plate, a fan, an injection adjustment valve, and the like. In the case shown in FIGS. 1 and 2, the adjustment mechanism 42 adjusts the dry air injected by the adjustment mechanism 42 so that the air volume of the dry air DA injected from above the electrode surface (the surface of the sheet 100) is greater than the air volume of the dry air DA injected from below the electrode surface (the back surface of the sheet 100). Of course, the ratio of the air volumes of the dry air injected from the upper and lower sides of the adjustment mechanism 42 to the electrodes can be adjusted as appropriate, for example, within a range of 0 to 100%.

[0021] Furthermore, the dry air supply device 4 adjusts so that the air volume of the upper dry air gradually increases according to the conveyance direction A1 of the sheet 100. Further, the dry air supply device 4 may divide the housing portion 3 into predetermined regions (for example, for each zone or each process), and adjust the injection amount of the dry air from above with a damper or the like provided in the duct 41.

[0022] The manufacturing apparatus 1 configured as described above manufactures a bipolar battery by performing a dry environment maintenance process for maintaining a dry environment in the housing portion 3 with dry air DA, and performing a coating process, a pressing process, a baking process, and a cell process in the housing portion 3.

[0023] The coating process is a process of thinly and uniformly coating the surface of a metal foil of a positive electrode active material or a negative electrode active material, which is a powder material and a liquid paste (slurry) mixed by a kneader, on the surface of a metal foil of (aluminum foil) or a negative electrode sheet (copper foil). Here, the paste is a solid-liquid suspension obtained by proportionally putting an active material, conductive carbon, thickener, binder, additive, solvent, etc. into a mixer and mixing them to be uniformly dispersed.

[0024] The pressing process involves applying pressure to the coated positive electrode sheet (aluminum foil) or negative electrode sheet (copper foil) using a roll press or similar device to compress it to the target thickness. The baking process involves drying the coated paste on the pressed positive electrode sheet or negative electrode sheet to remove the solvent, and then bonding the fixing material to the sheet (substrate) to create the positive electrode sheet or negative electrode sheet.

[0025] The cell process is a process in which the positive electrode sheet, negative electrode sheet, and separator, after the baking process, are stacked and wound around the axis to create a cylindrical wound electrode body.

[0026] In this manner, the manufacturing apparatus 1 maintains a dry environment by supplying dry air DA into the containment section 3 via the adjustment mechanism 42 through the dry air supply device 4, and in each of the coating, pressing, baking, and cell processes, it injects dry air DA while adjusting at least one of the injection direction and injection amount of dry air to the electrode surface on the sheet 100. This makes it possible to optimize the moisture content of the electrode coating on the sheet 100. In Embodiment 1, an example was described in which the coating, pressing, baking, and cell processes are performed in the containment section 3, but the apparatus is not limited to this, and each process may be performed in a separate device.

[0027] According to Embodiment 1 described above, the dry air supply device 4 performs an adjustment step in the dry environment maintenance step to adjust an adjustment mechanism 42 that can adjust at least one of the injection direction and injection amount of dry air to the electrode surface on the sheet 100, thereby optimizing the moisture content in the electrode coating (electrode surface) of the sheet 100.

[0028] (Embodiment 2) Next, Embodiment 2 will be described. Figure 3 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 2.

[0029] The bipolar battery manufacturing apparatus 1A shown in Figure 3 has the same configuration as the manufacturing apparatus 1 according to Embodiment 1, but differs in the direction in which the dry air DA supplied by the dry air supply device 4 is injected. Specifically, the dry air supply device 4 injects dry air DA only onto the upper side of the electrode surface coated on the upper surface of the sheet 100. For example, the dry air supply device 4 injects dry air DA only onto the upper side of the electrode surface coated on the upper surface of the sheet 100 so that it hits from the side of the coating film from which moisture is less likely to evaporate. In particular, in the case of a sheet 100 with a structure in which another coating film is applied on either side of the electrode surface, such as a bipolar electrode, there is a difference in the resistance to evaporation depending on the type of coating film, and by applying dry air DA from the side of the coating film from which moisture is less likely to evaporate, it is possible to suppress the adhesion of moisture to the remaining electrode.

[0030] According to the embodiment 2 described above, since the dry air supply device 4 sprays dry air DA only on the upper side of the coating film applied to the electrode surface on the upper surface of the sheet 100, by applying dry air DA from the coating film which is less likely to volatilize, it is possible to suppress the adhesion of moisture to the remaining electrode surface.

[0031] (Embodiment 3) Next, Embodiment 3 will be described. Figure 4 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 3.

[0032] The bipolar battery manufacturing apparatus 1B shown in Figure 4 has the same configuration as the manufacturing apparatus 1 according to Embodiment 1, and the dry air supplied by the dry air supply device 4 is injected diagonally with respect to the conveying direction A1 of the sheet 100. Furthermore, the dry air supply device 4 injects dry air DA onto the sheet 100 with a larger injection volume on the upper side compared to the injection volume on the lower side of the housing 3. The ratio of the airflow volumes of the upper and lower dry air DA injected by the adjustment mechanism 42 onto the electrodes can be adjusted as appropriate, for example, within a range of 0 to 100%.

[0033] According to Embodiment 3 described above, the dry air supply device 4 performs an adjustment step in the dry environment maintenance step to adjust an adjustment mechanism 42 that can adjust at least one of the injection direction and injection amount of dry air to the electrode surface on the sheet 100, thereby optimizing the moisture content in the electrode coating (electrode surface) of the sheet 100.

[0034] (Embodiment 4) Next, Embodiment 4 will be described. Figure 5 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 4. Figure 6 is a top view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 4.

[0035] The bipolar battery manufacturing apparatus 1C shown in Figures 5 and 6 further includes a moisture removal device 5 for removing moisture from the dry air DA, in addition to the configuration of the manufacturing apparatus 1 of the embodiment described above.

[0036] The moisture removal device 5 is connected to a duct 41 through which dry air DA is supplied via a duct 51. It is sprayed from the upper side of the containment unit 3 and collected from the lower side, where the dry air DA contains a small amount of moisture. The moisture removal device 5 then regenerates the dry air DA collected from the containment unit 3 according to its dew point, converting it into low-dew-point dry air DA and supplying it to the duct 41 to circulate the dry air DA.

[0037] In addition, in the manufacturing apparatus 1C, various sensors such as humidity sensors and temperature sensors may be installed in the duct 51, and the moisture content of the dry air DA circulating to the dry air supply device 4 may be adjusted by controlling the opening and closing of a valve 52 installed in the duct 51 according to the detection results of these various sensors.

[0038] According to Embodiment 4 described above, the moisture removal device 5 recovers dry air DA containing a small amount of moisture, regenerates the recovered dry air DA according to its dew point, and supplies it to the duct 41 as low-dew-point dry air DA, thus enabling the circulation of dry air DA.

[0039] (Embodiment 5) Next, Embodiment 5 will be described. Figure 7 is a cross-sectional view showing the schematic configuration of a bipolar battery manufacturing apparatus according to Embodiment 5.

[0040] The bipolar battery manufacturing apparatus 1D shown in Figure 7, in addition to the configuration of Embodiment 1, further includes a shutter 6 within the housing section 3 that separates area H1, where the replacement of the wound electrode body 101 such as the roll that supplies the sheet 100 takes place, from other areas H2. As a result, when an operator enters area H1 to replace the roll, the manufacturing apparatus 1D can maintain a controlled state of the dew point of the dry air DA in area H2 because the shutter 6 separates the space from area H2.

[0041] According to Embodiment 5 described above, by providing a shutter 6 within the housing section 3 that separates the area H1 where the winding electrode body 101, such as a roll for supplying the sheet 100, is replaced from the other area H2, it is possible to maintain a state in which the dew point of the dry air DA in area H2 is controlled.

[0042] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of symbols]

[0043] 1,1A,1B,1C,1D manufacturing equipment 2 Winding device 3. Storage area 4. Dry air supply device 5 Moisture removal device 6 shutters 20-25 Laura 41, 51 ducts 42 Adjustment mechanism 52 valves 100 sheets 101 Wound electrode body DA Dry Air H1 area H2 area K1 inside

Claims

1. A method for manufacturing a bipolar battery, The system includes a dry environment maintenance process in which a dry air supply device supplies dry air to maintain a dry environment inside the housing that houses a conveying device for transporting sheets having electrode surfaces. The aforementioned dry environment maintenance process is: The process includes adjusting an adjustment mechanism capable of adjusting at least one of the injection direction and injection amount of the dry air injected onto the electrode surface, A method for manufacturing bipolar batteries.

2. A method for manufacturing a bipolar battery according to claim 1, The adjustment mechanism is, Multiple nozzles are provided within the conveying equipment along the conveying direction for conveying the sheet, The aforementioned adjustment process is, The amount of dry air injected from the nozzle is adjusted to gradually increase at predetermined intervals along the conveying direction of the sheet. A method for manufacturing bipolar batteries.

3. A method for manufacturing a bipolar battery according to claim 1, The adjustment mechanism is, Multiple nozzles are provided vertically within the conveying equipment along the conveying direction for transporting the sheet, The aforementioned adjustment process is, 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. A method for manufacturing bipolar batteries.

4. A method for manufacturing a bipolar battery according to claim 1, The aforementioned adjustment process is, The dry air is sprayed in an oblique direction towards the conveying direction in which the sheet is conveyed. A method for manufacturing bipolar batteries.

5. A conveying device for conveying a sheet having an electrode surface, A housing section for housing the aforementioned transport device, A dry air supply device that supplies dry air into the storage area to maintain a dry environment inside the conveying equipment, Equipped with, The dry air supply device is The device has an adjustment mechanism that can adjust at least one of the injection direction and injection amount of the dry air injected onto the electrode surface. Manufacturing equipment for bipolar batteries.

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