Battery charge control device having a gassing detection unit without temperature sensor

摘要

A battery charge control device is capable of detecting a gassing state in a battery without using a temperature sensor. Under condition of charging the battery 5 with a charging current, when a terminal voltage Vi of the battery 5 monitored by the device exceeds a threshold value, a temporary-gassing detecting unit 23 informs a voltage regulation calculating unit 24 that the battery 5 is in course of reaching its gassing state. The voltage regulation calculating unit 24 calculates a changing rate of terminal voltage Vi of the battery 5 while it is in course of reaching the gassing state. When the calculated changing rate exceeds a preset decision value, a gassing detecting unit 25 judges that the battery 5 has just reached the gassing state. A decision value renewing unit 27 changes the decision value corresponding to the charging current. <IMAGE>