Electrolyte injection method

Abstract

To provide an electrolyte injection method that can reduce the impregnation time. [Solution] The electrolyte injection method involves injecting electrolyte into a battery module (S12), placing the battery module in a vacuum chamber, then evacuating the vacuum chamber to a pressure where the electrolyte does not boil, and finally opening the vacuum chamber to the atmosphere (S13, S14), repeating this process three or more times.

Description

Technical Field

[0001] The present invention relates to a method for injecting an electrolytic solution.

Background Art

[0002] Patent Document 1 describes a method for manufacturing an alkaline dry battery in which a positive electrode mixture and a separator are inserted into a battery case, an electrolytic solution is injected into the battery case, and the inside of the battery case is depressurized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the pressure at which the electrolytic solution boils is -90 kPa, it is impossible to achieve a vacuum pressure of -90 kPa or less, and there is a problem that the air in the battery module cannot be completely evacuated by a single evacuation. For example, if the evacuation is performed up to -90 kPa, about 10% of the air remains, and even in the second evacuation after the atmosphere is released, about 1% of the air remains. And because air remains in the battery module, if it takes time for the liquid to be impregnated, the number of equipment units and the number of jigs will increase.

Means for Solving the Problems

[0005] The electrolytic solution injection method according to one embodiment repeats the process of evacuating the battery module injected with the electrolytic solution to a pressure at which the electrolytic solution does not boil and then releasing the atmosphere three or more times.

Effects of the Invention

[0006] According to the electrolytic solution injection method of the present disclosure, it is possible to reduce the impregnation time.

Brief Description of the Drawings

[0007] [Figure 1] This is a flowchart showing an example of an electrolyte injection method according to Embodiment 1. [Figure 2] This figure shows one step of the electrolyte injection method according to Embodiment 1. [Figure 3] This figure shows one step of the electrolyte injection method according to Embodiment 1. [Figure 4] This figure shows one step of the electrolyte injection method according to Embodiment 1. [Modes for carrying out the invention]

[0008] Embodiment 1 Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a flowchart showing an example of an electrolyte injection method according to Embodiment 1. Figures 2, 3, and 4 show one step of the electrolyte injection method according to Embodiment 1.

[0009] In step S11 of Figure 1, the liquid injection jig 22 is set in module 21 as shown in Figure 2. Module 21 is, for example, a Li-ion battery module. Then the process proceeds to step S12.

[0010] In step S12, the electrolyte 23 is injected into the injection jig 22 as shown in Figure 2. Then the process proceeds to step S13.

[0011] In step S13, as shown in Figure 3, the liquid injection jig 22 and module 21 are evacuated in the vacuum chamber 24 to a pressure where the electrolyte 23 does not boil. The pressure at which the electrolyte 23 does not boil is, for example, -90 kPa. It is desirable to place a pressure gauge or pressure sensor inside the vacuum chamber 24 to measure the pressure inside the vacuum chamber 24. Then proceed to step S14.

[0012] In step S14, the vacuum chamber 24 is opened to the atmosphere. Then the process proceeds to step S15.

[0013] In step S15, it is determined whether the vacuuming in step S13 and the atmospheric release in step S14 have been performed three or more times. If the vacuuming in step S13 and the atmospheric release in step S14 have been performed three or more times, the process proceeds to step S16. If the vacuuming in step S13 and the atmospheric release in step S14 have been performed less than three times, the process returns to step S13.

[0014] In step S16, as shown in Figure 4, wait for the electrolyte 23 to impregnate the module 21, then remove the liquid injection jig 22 from the module 21.

[0015] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, the more times the vacuuming in step S13 and the release to the atmosphere in step S14 are repeated, the greater the amount of air that escapes from the battery cell, thus enabling impregnation in a shorter time. Therefore, the number of repetitions may be adjusted to match the required cycle time.

[0016] For example, if the required impregnation amount for a battery cell is ±0.08% ml of the liquid volume, then at least four vacuuming cycles are necessary to ensure no air remains (four vacuuming cycles). This process removes 99.99% of the air from the battery cells. [Explanation of Symbols]

[0017] 21 modules 22 Injection jig 23 Electrolyte 24 Vacuum Chamber

Claims

[Claim 1] Inject electrolyte into the battery module, The battery module is placed inside the vacuum chamber, An electrolyte injection method comprising the steps of evacuating the vacuum chamber to a pressure that prevents the electrolyte from boiling, and then opening the vacuum chamber to the atmosphere, repeating this process three or more times.

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