Method for manufacturing bipolar battery

Abstract

To provide a method for manufacturing a bipolar battery which can secure the performance of a battery.SOLUTION: A method for manufacturing a bipolar battery includes: a liquid injection impregnation step of injecting an electrolyte liquid into a liquid injection port for impregnation; a provisional sealing step of sealing by a provisional sealing film; a provisional sealing cancelling step of opening a hole in the provisional sealing film, the hole having a smaller opening area than the liquid injection port; an activation step of performing activation processing including an initial charge and a high-temperature aging; and a final sealing step of sealing by a final sealing film.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a bipolar battery.

Background Art

[0002] In battery manufacturing, it is known that gas is generated during the first charge in the activation process and high-temperature aging (see Patent Document 1). Also, in high-temperature aging, the gas in the surplus space inside the cell expands.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, a battery requires an exterior body that can withstand the rising internal pressure. When the exterior body is made of aluminum, it can withstand the internal pressure increase even in a sealed system during the activation process. Also, when the exterior body is a laminate film, the destruction of the exterior body can be prevented by assembling an excessive amount of laminate film. On the other hand, in the case of a bipolar battery, since the electrodes (current collectors) with the positive and negative electrodes coated on one side each are laminated, the structure is structurally weak. Therefore, there is a risk that it cannot withstand the internal pressure increase. In particular, in the case of a high-capacity battery, a large amount of gas is generated, and since the dead space inside the cell becomes small when as much active material as possible is put into the cell to increase the energy density, this becomes a problem.

[0005] Also, if the activation process is carried out with the system open to suppress the internal pressure increase, the electrolyte necessary for ensuring the battery performance will volatilize.

[0006] An object of the present invention is to provide a method for manufacturing a bipolar battery that can ensure the battery performance.

Means for Solving the Problem

[0007] The method for manufacturing a bipolar battery according to claim 1 includes a liquid injection and impregnation step of injecting an electrolytic solution from an injection port and impregnating it, a temporary sealing step of sealing with a temporary sealing film after the liquid injection and impregnation step, a temporary sealing release step of making a hole in the temporary sealing film having an opening area smaller than that of the injection port after the temporary sealing step, an activation step of performing an activation treatment including initial charging and high-temperature aging after the temporary sealing release step, and a final sealing step of sealing with a final sealing film after the activation step.

[0008] In the method for manufacturing a bipolar battery according to claim 1, an activation treatment is performed after the temporary sealing release step. In the temporary sealing release step, a hole having an opening area smaller than that of the injection port is made in the temporary sealing film. Therefore, compared with the case where the activation treatment is performed with the temporary sealing film having no hole, the internal pressure is less likely to rise in the activation step. As a result, the activation treatment can be performed without destroying the exterior body even in a bipolar battery.

[0009] Also, the hole made in the temporary sealing release step is a hole having an opening area smaller than that of the injection port. Therefore, compared with the case where the activation step is performed simply with the injection port opened, the volatilization of the electrolytic solution can be suppressed. As a result, the performance of the battery can be ensured.

[0010] The method for manufacturing a bipolar battery according to claim 2 further includes a cooling step of cooling to room temperature after the high-temperature aging in claim 1, and evacuation is performed before sealing by the temporary sealing step and the final sealing step.

[0011] In the method for manufacturing a bipolar battery according to claim 2, it further includes a cooling step of cooling to room temperature after the high-temperature aging, and evacuation is performed before sealing by the temporary sealing step and the final sealing step. Gas is particularly likely to be generated in these steps. It is easier to remove the generated gas more efficiently.

Advantages of the Invention

[0012] As described above, according to the present invention, a method for manufacturing a bipolar battery capable of ensuring the performance of the battery can be provided.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0014] Hereinafter, a method for manufacturing a bipolar battery according to an embodiment will be described.

[0015] First, the bipolar battery 10 of the embodiment (hereinafter simply referred to as the battery 10) will be described.

[0016] As shown in FIG. 2, the battery 10 includes a plurality of cells 12 stacked in series. The battery 10 may also be called a battery module. Hereinafter, the number of cells 12 included in the battery 10 is set to N.

[0017] Each cell 12 has a current collector 20 on the positive electrode side, a positive electrode 30, a separator 40, a negative electrode 50, and a current collector 20 on the negative electrode side.

[0018] The battery 10 is a bipolar battery. That is, two adjacent cells 12 among the N cells 12 share the current collector 20. For example, the current collector 20 on the negative electrode side of the cell 12 in the k-th layer and the current collector 20 on the positive electrode side of the cell 12 in the k-1-th layer are the same current collector 20.

[0019] The current collector 20 has a negative electrode side foil 22 and a positive electrode side foil 24. The negative electrode side foil 22 is, for example, a copper foil, and the positive electrode side foil 24 is, for example, an aluminum foil.

[0020] The positive electrode 30 is, for example, LFP (lithium iron phosphate). The negative electrode 50 is, for example, graphite. The formation region of the negative electrode 50 in the current collector 20 is slightly larger than the formation region of the positive electrode 30.

[0021] The end portion of the separator 40 is held together with the current collector 20 on the negative electrode side out of the positive electrode side and the negative electrode side.

[0022] Each cell 12 has a liquid injection port 62 for injecting the electrolytic solution 14 into the cell 12. The liquid injection port 62 is connected to the space on the positive electrode 30 side with respect to the separator 40 within the cell 12. Note that the electrolytic solution 14 is, for example, a non-aqueous electrolytic solution.

[0023] Each cell 12 is held by a holder 60 made of a synthetic resin.

[0024] (Manufacturing method) As shown in FIG. 1, the manufacturing method of the bipolar battery 10 of the present embodiment includes a liquid injection impregnation step, a temporary sealing step, a temporary sealing release step, an activation step including initial charging and high-temperature aging, and a final sealing step.

[0025] In the liquid injection impregnation step, the electrolytic solution 14 is injected from the liquid injection port 62 and impregnated.

[0026] In the temporary sealing step, after the liquid injection impregnation step, it is sealed with a temporary sealing film. Specifically, vacuum pumping is performed before sealing. This makes it easy to remove the gas generated inside the battery.

[0027] In the temporary sealing release step, after the temporary sealing step, a hole having an opening area smaller than that of the liquid injection port 62 is made in the temporary sealing film. Thereby, the gas generated in the subsequent activation step can escape from the hole, and an increase in internal pressure can be suppressed.

[0028] In the activation step, after the temporary sealing release step, an activation treatment including initial charging and high-temperature aging is performed. Specifically, a step of cooling to room temperature is provided after the high-temperature aging. This makes it easy to remove the gas generated inside the battery.

[0029] In this sealing process, after the activation process, sealing is performed using the main sealing film. Specifically, evacuation is performed before sealing. This makes it easier to remove the gas generated inside the battery.

[0030] <Function and Effect> As described above, in this embodiment, after the temporary sealing release process, an activation treatment is performed. In the temporary sealing release process, a hole having an opening area smaller than that of the liquid injection port 62 is formed in the temporary sealing film. Therefore, compared with the case where the activation treatment is performed with the temporary sealing film not having a hole, the internal pressure is less likely to increase in the activation process. As a result, even in the bipolar battery 10, the activation treatment can be performed without destroying the exterior body.

[0031] Also, the hole formed in the temporary sealing release process is a hole having an opening area smaller than that of the liquid injection port 62. Therefore, compared with the case where the activation process is performed simply with the liquid injection port 62 being open, volatilization of the electrolytic solution 14 can be suppressed. As a result, the performance of the battery 10 can be ensured.

[0032] [Supplementary Explanation of the Above Embodiment] Note that, in the above embodiment, after high-temperature aging, a cooling process of cooling to room temperature is further included, but the present invention is not limited thereto.

[0033] Also, in the above embodiment, evacuation is performed before sealing by the temporary sealing process and the main sealing process, but the present invention is not limited thereto.

Explanation of Reference Numerals

[0034] 10 Bipolar battery 62 Liquid injection port

Claims

1. A liquid injection and impregnation step of injecting an electrolyte from an injection port and impregnating it; A temporary sealing step of sealing with a temporary sealing film after the liquid injection and impregnation step; A temporary sealing release step of making a hole in the temporary sealing film with an opening area smaller than that of the injection port after the temporary sealing step; An activation step of performing an activation treatment including initial charging and high-temperature aging after the temporary sealing release step; A final sealing step of sealing with a final sealing film after the activation step; A method for manufacturing a bipolar battery including the above steps.

2. Further including a cooling step of cooling to room temperature after the high-temperature aging, Performing vacuum pumping before sealing by the temporary sealing step and the final sealing step, The method for manufacturing a bipolar battery according to Claim 1.

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