The breaker is provided with a fixed contact, a movable piece having an elastic portion and a movable contact, a thermally-actuated element deforming with a change in the temperature so as to shift the movable piece from a conduction state to a cut-off state, a case main body housing the movable piece and the thermally-actuated element, a lid member attached to the case main body, and a plate-shaped cover piece embedded in the lid member. The case main body is provided with a first fixing surface fixed to the lid member, and the lid member is provided with a second fixing surface fixed to the case main body. The second fixing surface is provided with a protruding portion protruding toward the first fixing surface, and the protruding portion and the cover piece are overlapped with each other in the plan view as viewed in the thickness direction of the cover piece.

A device for controlling battery operation includes a battery cell, a thermal cutoff, and a battery management system. The thermal cutoff is coupled in series between the battery cell and a system load of the device. The thermal cutoff has at least three terminals. A first terminal of the thermal cutoff is electrically-coupled to the battery cell and a second terminal of the thermal cutoff is electrically-coupled to the system load. The thermal cutoff includes a permanent failure mechanism having an open state and closed state wherein the closed state allows electrical communication between the first terminal and the second terminal. The battery management system is electrically-coupled to a third terminal of the thermal cutoff. The permanent failure mechanism permanently switches to the open state in response to an electrical signal from the battery management system.

A protection device includes a movable arm, a fixed terminal, and a bimetallic member, and a casing that accommodates them, the bimetallic member is located either above or below the movable arm, one end of the bimetallic member applies force to one end of the movable arm, thereby holding one end of the movable arm and the fixed terminal in contact.

A current cut-off device includes a plate-shaped terminal piece having a contact, a movable piece including an elastic portion formed in a plate shape so as to be elastically deformed and a movable contact arranged at one end portion of the elastic portion and having the movable contact so as to be pressed against and in contact with the contact, and a thermally actuated element which biases the movable piece by deforming in accordance with a temperature change and causes a state of the movable piece to be shifted from a conductive state in which the movable contact is in contact with the contact to a cut-off state in which the movable contact is separated from the contact. When the state of the movable piece is shifted from the conductive state to the cut-off state, as the movable contact moves, it gets over the contact.

A breaker includes a fixed piece having a fixed contact, a movable piece having an elastically deformable elastic portion and a movable contact formed at a tip portion of the elastic portion and pushed to contact with the fixed contact, a thermally actuated element deformable according to a temperature change to shift the state of the movable piece from a conductive state to a cut-off state, and a case accommodating the fixed piece, the movable piece, and the thermally actuated element. The movable piece is cantilevered by the case on a base end portion side of the elastic portion, the elastic portion includes a first narrow portion having a smaller width dimension in a short direction perpendicular to a longitudinal direction of the elastic portion than the base end portion, and the first narrow portion has an arc-shaped contour in plan view from a thickness direction of the elastic portion.

A temperature-dependent switch comprises a first stationary contact, a second stationary contact, and a temperature-dependent switching mechanism having a movable contact member. In its first switching position, the switching mechanism presses the contact member against the first contact and thereby produces an electrically conductive connection between the two contacts. In its second switching position, the switching mechanism keeps the contact member spaced apart from the first contact. The temperature-dependent switching mechanism further comprises first and second temperature-dependent snap-action parts which switch from geometric low-temperature configurations to geometric high-temperature configurations when exceeding first and second switching temperatures, respectively, and switch back when subsequently falling below first and second reset temperatures, respectively. Switching the first and/or the second snap-action part from its geometric low-temperature configuration to its geometric high-temperature configuration brings the switching mechanism from its first switching position to its second switching position.

A temperature-dependent switch comprising first and second stationary contacts and a temperature-dependent switching mechanism having a movable contact member. The switching mechanism, in its first switching position, presses the contact member against the first contact and thereby produces an electrically conductive connection between the two contacts via the contact member and, in its second switching position, keeps the contact member spaced apart from the first contact and thereby disconnects the electrically conductive connection between the two contacts and opens the switch. The switch further comprises a closing lock that, as soon as it is activated, prevents the switch once having opened from closing again by keeping the switching mechanism in its second switching position. The closing lock comprises a locking element having a shape-memory alloy and an opening through which the movable contact member protrudes. The locking element is configured to change its shape upon exceeding a locking element switching temperature from a first shape, in which the locking element does not activate the closing lock, into a second shape, in which the locking element activates the closing lock by exerting a force on a part of the switching mechanism, which force holds the switching mechanism in its second switching position.

A temperature-dependent switch having a housing with an upper part and a lower part, wherein a first and a second stationary contact are arranged on the housing, and a temperature-dependent switching mechanism having a movable contact member. In its first switching position, the switching mechanism presses the movable contact member against the first contact and thereby produces an electrically conductive connection between the two contacts via the contact member, and, in its second switching position, keeps the movable contact member spaced apart from the first contact. A closing lock prevents the switch, once having opened, from closing again by locking the switching mechanism permanently in its second switching position in a mechanical manner. The closing lock comprises a substantially disc-shaped locking element and a first latching member, which, in order to lock the switching mechanism, interacts in the second switching position with a second latching member that is arranged on the movable contact member.

A thermal protector includes, in a fixed manner, a first terminal and a second terminal that are respectively connected to external circuits, at lower left/right ends of the longitudinal directions of a base, and a right end at which a movable plate and a bimetal are superimposed is fixed to the right end of the upper surface of the base and is connected to the second terminal. A fixed contact is fixed to an internal end of the first terminal that is exposed in the left end of the base. A movable contact is fixed at a position facing the fixed contact on the lower surface of the left end of the movable plate. A partition wall that encloses the movable contact and the fixed contact from three directions is provided and bent plate planes are formed on both sides of the movable plate in the vicinity of the movable contact. The bent plate planes adjust the flow direction of hot air in cooperation with the partition wall so as to prevent a malfunction of a breaking arc flying to surrounding conductive members.

A thermally responsive switch includes a heating element with a meandering portion formed of a metal plate. The meandering portion is bent twice with respect to reference axes extending in a longitudinal direction of a housing. The meandering portion includes an outer vertical portion that is perpendicular to an inner surface of a lid plate, an inner vertical portion that is perpendicular to the inner surface of the lid plate, and a middle vertical portion that is disposed between the outer vertical portion and the inner vertical portion and is perpendicular to the inner surface of the lid plate. The middle vertical portion has a narrow portion narrower than a width of the middle vertical portion. The narrow portion is provided on an end portion located in one side of the middle vertical portion where no other heating element exists among the two widthwise end portions of the middle vertical portion.