Abstract: The female connectors are made up of a power part (9), (15) (23), (34), (37), and a male electrode receiver (10), (16), (24), (38), (41) (46). The male electrode receiver is made up of a short right-angled part (11) (18) (26) (48); a first flat section (12) (17) (25), an arced section (13) (19) (27) (47) and a second flat section (14) (21) (29). The arced section can have the flat portion (20) and the second flat section can have a right-angled extension (30). The power part can be a bus bar (49) or a male electrode as indicated by a dashed line (51).