Patent ID: 9529050
Filing Date: 2016-12-27
CPC Classification: B60L,G01R,H01M,Y02E,Y02T

Claim Text:
1. A diagnostic device that judges degradation of a rechargeable battery comprising: means for breaking charge current of the rechargeable battery to change the terminals of the rechargeable battery to an open state, the rechargeable battery in a charging state connected to a charge circuit during charging of the rechargeable battery, or means for breaking discharge current of the rechargeable battery to change the terminals of the rechargeable battery to an open state, the rechargeable battery connected to a discharge circuit during discharging of the rechargeable battery; a voltage measurement part which measures terminal voltage of the rechargeable battery for which charge current or discharge current is broken by the breaking means; means for diagnosing degradation of the rechargeable battery based on the temporal change of terminal voltage measured by the voltage measurement part; and a display connected to the diagnosing means that displays a judgement result, wherein said diagnostic means judges whether the rechargeable battery is degraded or not based on a comparison of measured falling or rising speed of the terminal voltage of the rechargeable battery to be diagnosed immediately after the breaking and calculated falling or rising speed of the terminal voltage of a healthy rechargeable battery immediately after the breaking, wherein said calculated falling or rising speed is calculated based on a thickness of a separator and a coefficient of ion diffusion of the healthy rechargeable battery.