Balance and safety discharge circuit for energy storage devices

A safety discharge circuit for energy storage devices connected in series, comprising:

• a plurality of energy storage devices, each energy storage device connected in parallel to a discharge resistor, and an electrically controllable switch connected between each energy storage device and each respective discharge resistor;
• and
• a controller connected to the electrically controllable switches and connectable to a charging source;
• wherein:
• the controller is configured to output an electrical signal to the electrically controllable switches;
• and
• a presence or absence of the output of the electrical signal is determinative of a discharge state of the energy storage devices.

A method for safety discharging energy storage devices connected in series, the method comprising the steps of:

• providing an energy storage apparatus including:
• a plurality of energy storage devices connected in series;
• a plurality of discharge resistors, each discharge resistor connected in parallel to one of the energy storage devices;
• a plurality of electrically operated switches, each electrically operated switch connected between one of the energy storage devices and a respective one of the discharge resistors;
• and
• a controller connected to the electrically operated switches and connectable to a charging source, the controller configured to output an electrical signal to the electrically operated switches, wherein a presence or absence of the output of the electrical signal is determinative of a discharge state of the energy storage devices;
• outputting, by the controller, the electrical signal to the electrically operated switches to maintain the electrically operated switches in an open state corresponding to an inactive discharge state of the energy storage devices;
• and
• interrupting, by the controller, the electrical signal output to the electrically operated switches to cause the electrically operated switches to close corresponding to an active discharge state of the energy storage devices.