BATTERY SYSTEM HAVING WATERPROOF STRUCTURE

In a battery system, an output lead is exposed at an opening of an outer case, and the outer case accommodates a cradle mounting a lead plate and disposed at a fixed position. The cradle includes an upper plate allowing the lead plate to be disposed on the upper plate, a peripheral wall disposed around the lead plate, a drainage hole opened in the upper plate, and a drainage channel for water flowing from the drainage hole. The outer case is provided with a drainage opening allowing water flowing from the drainage channel to be externally drained. The lead plate includes a planar part disposed inside the peripheral wall, and a rising part crossing over the peripheral wall. Entering water flowing from the opening flows from the drainage hole and passes through the drainage channel to be externally drained out of the drainage opening of the outer case.