The present invention relates to one or more electrode plates, which are installed with current collecting terminals at two or more sides thereof, and joined to an auxiliary conductor made of a material having a conductivity that is higher than that of the electrode plates. Current collecting terminals are installed at two or more sides of the auxiliary conductor, for linking with current collecting terminals installed at two or more sides of the electrode plates, and at least one of linked terminals is used as a general current collecting terminal to output current to an external part or to receive input current from the external part. Finally, insulators installed between the auxiliary conductor and the electrode plates to constitute an electrode unit.