Abstract: The disclosure provides a battery pack, a battery thermal management system and a battery thermal management control method. The battery pack includes: a housing, a bracket and a battery cell. The housing is provided with an accommodation space. The bracket is arranged in the accommodation space, which forms at least one accommodation cavity with the accommodation space. The battery cell is arranged in the accommodation cavity, and at least one heat dissipation passage is opened in the accommodation cavity. At least one fan is arranged on one side of the heat dissipation passage to suck or blow air to the heat dissipation passage. Compared with the prior art, the battery pack of the disclosure has an active heat dissipation function while satisfying waterproofing.

Abstract: Disclosure is a multi-voltage battery pack which includes: a housing, battery strings disposed inside the housing and including a plurality of battery cells, a battery interface disposed on the housing for use with the power tool, and a converting assembly disposed within the housing and electrically connected to the battery strings. The converting assembly has a first state, a second state, and a third state. The multi-voltage battery pack can separately output a first operating voltage, a second operating voltage, and a third operating voltage. The third operating voltage is greater than the second operating voltage, and the second operating voltage is greater than the first operating voltage.

Abstract: The disclosure provides a charger, a charging device, an energy supply device and a control method of the charger. The charger comprises a housing, a charging position, a charging port and a first heat dissipation unit. The charger comprises a base and a supporting part. The supporting part is arranged on the base. The charging position is arranged on the base and distributed around the supporting part. The charging port is arranged on the charging position and matched with a battery pack. The first heat dissipation unit is arranged on the supporting part for heat dissipation of the battery pack. With the charger of the disclosure, multiple battery packs can be charged at the same time.