Battery pack and wireless linking system

A battery pack that supplies a driving power source to a power tool, the battery pack comprising:

• a wireless communication unit, communicating wirelessly with an external device;
• a control unit;
• a first cell unit and a second unit in which a plurality of battery cells are connected in series;
• a first positive terminal and a first negative terminal connected with the first cell unit;
• and
• a second positive terminal and a second negative terminal connected with the second cell unit,
• wherein the battery pack is configured as being connectible with, as the power tool, one of a first power tool driven a first voltage and a second power tool driven a second voltage higher than the first voltage,
• wherein when the battery pack is connected to the first power tool, the first positive terminal and the second positive terminal, and the first negative terminal and the second negative terminal are configured to be respectively short-circuited by a tool-side positive terminal and a tool-side negative terminal of the first power tool, so that the first cell unit and the second cell unit are connected in parallel, or
• wherein when the battery pack is connected to the second power tool, the first positive terminal and the second negative terminal are configured to be respectively connected with a tool-side positive terminal and a tool-side negative terminal of the second power tool, and the second positive terminal and the first negative terminal are connected, so that the first cell unit and the second cell unit are connected in series.