BATTERY MANUFACTURING METHOD AND MANUFACTURING DEVICE

The present invention has a first depressurization step of depressurizing the inside of a liquid injecting chamber, an injection step of injecting, in the inside of the liquid injecting chamber, a liquid electrolyte into the battery through an opening portion formed at the top end of an outer case body of the battery, a second depressurization step of depressurizing the inside of a sealing chamber and a sealing step of sealing the opening portion in the inside of the sealing chamber. Vacuum attainment time T until the pressure of the inside of the liquid injecting chamber becomes at a predetermined vacuum degree is measured in the first depressurization step, and if this vacuum attainment time T exceeds first threshold Ts1, a depressurization rate is reduced and a depressurization time is extended.