ENERGY STORAGE MODULE AND AN ENERGY STORAGE SYSTEM FOR A POWER GRID

There is disclosed herein an energy storage module (10) for an energy storage system (4) connected to a power grid (2). The energy storage module comprises an energy storage unit (20) having an equivalent capacitance (22). The energy storage unit has an internal resistance (24). The energy storage module further comprises a bypass circuit (30) connected in parallel to the energy storage unit. The bypass circuit comprises a bypass switch (32) and a current limiting device (34) connected in series. A resistance of the current limiting device is less than 500 % of the internal resistance of the energy storage unit. There are also disclosed herein an energy storage system and a power grid system.