Storage battery used for traction, and method for identifying liquid level in same

The invention relates to a storage battery used for traction, and a method for identifying liquid level in the storage battery used for traction, and especially relates to a storage battery used for traction comprising a liquid detection system. The storage battery used for traction comprises two electrodes at interval, an analysis unit, and a controller. The electrodes are arranged in the storage battery used for traction, wherein the electrode comprises a first segment and a second segment which are opposite. A relative large first distance is between the first segments of the electrodes, and a relative small second distance is between the second segments of the electrodes. A transition mark indicates special liquid level of the liquid between the first segment and a second segment. The analysis unit comprises a resistance measurement unit. The resistance measurement unit is used to provide successive resistance data on time. The resistance data respectively indicates resistance between the electrodes. The