A relay control system for a battery system is provided. The relay control system includes: an electrical interface configured to detachably receive a connector; a power supply electrically connected in parallel to a coil of a relay through power supply lines; a relay driver switch interconnected between the power supply and the coil in one of the power supply lines; and a controller electrically connected in parallel to the relay driver switch through relay driver control lines to control the relay driver switch. One of the power supply lines or the relay driver control lines is routed across the interface, and the relay control system is configured to open the relay when the one of the power supply lines or the relay driver control lines is interrupted in response to the connector being detached from the interface.

A manual service disconnect for the in-vehicle electric current, which has a switch seat, a safety plug assembly, and a protection cover. The switch seat has a seat portion and a plug holder. The plug holder is provided with multiple power legs. The seat portion is hollow inside and has a plug port and a wire opening. The plug holder is disposed in the seat portion and faces the plug port. The power legs project from the wire opening. The safety plug assembly has a plug portion matching the seat portion and a plug head disposed on the plug portion. The protection cover is disposed on the seat portion and covers the wire opening to cover the power legs for protection.

A manual service disconnect for the in-vehicle electric current, which has a switch seat, a safety plug assembly, and a protection cover. The switch seat has a seat portion and a plug holder. The plug holder is provided with multiple power legs. The seat portion is hollow inside and has a plug port and a wire opening. The plug holder is disposed in the seat portion and faces the plug port. The power legs project from the wire opening. The safety plug assembly has a plug portion matching the seat portion and a plug head disposed on the plug portion. The protection cover is disposed on the seat portion and covers the wire opening to cover the power legs for protection.

A power circuit interrupting device including a first housing including a pair of fixed electrodes and a fuse having terminals at both ends thereof, and a second housing including a moveable electrode, the moveable electrode interrupting electrical connection between the fixed electrodes when the second housing is uncoupled from the first housing, and establishing the electrical connection between the fixed electrodes when the second housing is coupled with the first housing. The first housing has an opening provided for carrying out a continuity test for the fuse. The opening is always covered with the second housing in a condition that continuity of a circuit is allowed. The power circuit interrupting device serves to facilitate the continuity test for the fuse built therein and comply with such a maintenance procedure that the continuity test should be carried out after interrupting continuity of the power circuit.

A power circuit shut off device includes a housing and a switch portion provided in the housing, and an operating member configured to turn on or turns off the switch portion. The switch portion includes a pair of terminals arranged along a bottom face of the housing, an electric conductive member having contact point portions and that is elastically urged toward the pair of terminals, and an insulating movable member configured to move along a direction in which the pair of terminals are arranged. The pair of terminals are brought into electric conductive to each other when the pair of terminals contact the contact point portions respectively. The insulating movable member is moved between a shut-off position and a conductive position by an operation on the operating member.

A connector device includes a pair of first terminals, a second terminal, and a cover body. The first terminals are arranged in parallel. The second terminal includes a pair of contact points that are electrically connected to the respective first terminals, and is biased by a spring so that the contact points collectively sandwich the first terminals. The cover body made of a resin is attached to tip parts of the first terminals. The cover body includes first guide surfaces that have the contact points of the second terminal sliding thereon and guide the contact points in a direction for separating the contact points when the first terminals are connected to the second terminal. Thus, wear of the first terminals and the second terminal can be reduced.

A connector includes a first and second connector housings, a first and second terminals provided in the first and second connector housings, the second terminal including contact pieces with a gap therebetween, the gap being larger than a width dimension of the first terminal. The second connector housing includes pressing plate portions. The second terminal is to be accommodated between the pressing plate portions, the second terminal being displaceable between a first position and a second position, a part of the contact pieces extends beyond distal ends of the pressing plate portions when the second terminal is in the first position, the part of the contact pieces are completely retracted into a space between the pressing plate portions when the second terminal is in the second position. The contact pieces are to be pushed such that the contact pieces contact the terminal plate portions.

A power circuit shut off device includes a housing and a switch portion provided in the housing, and an operating member configured to turn on or turns off the switch portion. The switch portion includes a pair of terminals arranged along a bottom face of the housing, an electric conductive member having contact point portions and that is elastically urged toward the pair of terminals, and an insulating movable member configured to move along a direction in which the pair of terminals are arranged. The pair of terminals are brought into electric conductive to each other when the pair of terminals contact the contact point portions respectively. The insulating movable member is moved between a shut-off position and a conductive position by an operation on the operating member.

A connector includes a first and second connector housings, a first and second terminals provided in the first and second connector housings, the second terminal including contact pieces with a gap therebetween, the gap being larger than a width dimension of the first terminal. The second connector housing includes pressing plate portions. The second terminal is to be accommodated between the pressing plate portions, the second terminal being displaceable between a first position and a second position, a part of the contact pieces extends beyond distal ends of the pressing plate portions when the second terminal is in the first position, the part of the contact pieces are completely retracted into a space between the pressing plate portions when the second terminal is in the second position. The contact pieces are to be pushed such that the contact pieces contact the terminal plate portions.

A power supply circuit breaking device includes a first connector housing, a second connector housing, a main lock unit locking in a finally fitted state in which the second connector housing is completely fitted to the first connector housing, a sub-lock unit locking in a temporarily fitted state in which a part of the second connector housing is fitted to the first connector housing, a main switch unit switched on in the finally fitted state and the temporarily fitted state, and a sub-switch unit switched on in the finally fitted state and switched off in the temporarily fitted state. The sub-lock unit includes a sub-lock claw formed in the first connecter housing, and an operation portion provided in the second connector housing and having an engaging plate portion engaged with the sub-lock claw in the temporarily fitted state.