METHOD FOR MANUFACTURING POWER STORAGE DEVICE, POWER STORAGE DEVICE, AND METHOD FOR SUPPRESSING THE REDUCTION IN VOLTAGE OF POWER STORAGE DEVICE

PROBLEM TO BE SOLVED: To provide a method for manufacturing a power storage device, which enables the suppression of the reduction in voltage in charging a power storage device.SOLUTION: A method for manufacturing a power storage device 1 comprises the step of encasing an ultrasonic-welded electrode body, an electrolytic solution, and an additive agent having a nitrile group in a case 3. The step of encasing the electrode body, the electrolytic solution, and the additive agent in the case 3 includes: encasing the electrode body in the case 3 and then, putting the electrolytic solution in the case 3 over twice or more times, provided that a part of the electrolytic solution enclosed in the case 3 first contains the additive agent, or a part of the electrolytic solution to be put in the case 3 second or in a subsequent turn, of which the concentration of the additive agent is lower than that in the part of the electrolytic solution to be enclosed first.EFFECT: It is possible to suppress a fine short circuit between positive and negative electrodes with the aid of the additive agent having the nitrile group, which serves to capture metallic powder produced in ultrasonic welding.SELECTED DRAWING: Figure 1 【課題】蓄電素子を充電する際の電圧低下を抑制した、蓄電素子の製造方法を提供する。【解決手段】超音波溶接された電極体、電解液、及び、ニトリル基を有する添加剤をケース３に収容させることを含む、蓄電素子１の製造方法。電極体、電解液、及び、添加剤をケース３に収容させる際に、電極体をケース３に収容させた後、ケース３に２回以上に分けて電解液を収容させることを含み、ケース３に第１回目に収容させる電解液は、添加剤を含有する。又は、第１回目に収容させる電解液に比べて添加剤の濃度が低い電解液を第２回目以降にケース３に収容させる蓄電素子１の製造方法。【効果】超音波溶接時に発生する金属粉をニトリル基を有する添加剤が捕捉し、正極・負極間微短絡を抑制できる【選択図】図１