Electric energy storage device and electric tool system

A power tool system, comprising:

• an electric energy storage device, a low-voltage power tool, a medium-voltage power tool and a high-voltage power,
• the electric energy storage device for providing a plurality of output voltages comprising:
• N energy units;
• and
• M energy modules, N energy units being divided into M energy modules, each of the energy modules comprising K energy units,
• wherein, M≥2 and K≥1,
• wherein, two adjacent energy units are switchable in series or parallel, and two adjacent energy modules are switchable in series or parallel,
• wherein, the output voltages comprise a low voltage, a medium voltage and a high voltage, and
• wherein, the electric energy storage device provides the low voltage when connecting to the low-voltage power tool, the electric energy storage device provides the medium voltage when connecting to the medium-voltage power tool, and the electric energy storage device provides the high voltage when connecting to the high-voltage power tool.

An electric energy storage device for providing a plurality of output voltages, comprising:

• N energy units;
• and
• M energy modules, N energy units being divided into M energy modules, each of the energy modules comprising K energy units,
• wherein M≥2 and K≥1,
• wherein at least two adjacent energy units are switchable in series or parallel,
• wherein at least two adjacent energy modules are switchable in series or parallel, and
• wherein a rated voltage of each of the energy units is n V, and each of the output voltages of the electric storage device is n V to M*n V.