SWITCH AND BATTERY SYSTEM

A switch assembly for a battery module comprises a base unit, a first plug, and a second plug. The base unit defines a socket in which are located first and second positive contacts and first and second negative contacts. The first plug is configured to be inserted into the socket and comprises a first connector operable to connect the first positive contact to the second positive contact and a second connector operable to connect the first negative contact to the second negative contact when the first plug is inserted into the socket. The second plug comprises a connector operable to connect only the first positive contact to the second negative contact when the second plug is inserted into the socket.