Proposed is a current collector for a positive electrode that substitutes for metal foil and includes a polymer film made of a nonmetal, nonconductor material, and an aluminum conductive material configured to define an outermost surface of the current collector for a positive electrode by being formed or applied, with a thickness of 0.25 to 0.6 μm, onto at least one of upper and lower surfaces of the polymer film, in which the conductive material serves as an electrochemical fuse or performs a function of blocking or reducing short-circuit current in the event of an internal short circuit or an external short circuit.

A battery module comprising a plurality of battery cells (2), which are each connected electrically conductively in series and/or in parallel with one another, and comprising a switching device (3), which has a first terminal (31) and a second terminal (32), wherein a first electrically conductive connecting element (41) connects the first terminal (31) of the switching device (3) electrically conductively to a first terminal (51) of a fuse element (5), and a second terminal (52) of the fuse element (5) is electrically conductively connected to a voltage tap (61) of a terminally arranged battery cell (2, 21), and a second electrically conductive connecting element (42) connects the second terminal (32) of the switching device (3) electrically conductively to a voltage tap (62) of the battery module (1).

A battery module comprising a plurality of battery cells (2), which are each connected electrically conductively in series and/or in parallel with one another, and comprising a switching device (3), which has a first terminal (31) and a second terminal (32), wherein a first electrically conductive connecting element (41) connects the first terminal (31) of the switching device (3) electrically conductively to a first terminal (51) of a fuse element (5), and a second terminal (52) of the fuse element (5) is electrically conductively connected to a voltage tap (61) of a terminally arranged battery cell (2, 21), and a second electrically conductive connecting element (42) connects the second terminal (32) of the switching device (3) electrically conductively to a voltage tap (62) of the battery module (1).

A battery pack includes a battery pack housing, a plurality of battery pack terminals, and a plurality of battery cells supported within the battery pack housing. At least one battery cell includes a battery cell terminal. The battery pack also includes a compound fuse electrically coupled between the battery cell terminal of the at least one battery cell and at least one battery pack terminal. The compound fuse comprises a first material and a second material that has a lower melting point than the first material. The compound fuse includes a first portion electrically coupled to the battery cell terminal, a second portion electrically coupled to the at least one battery pack terminal, and a fuse portion that connects the first portion to the second portion. The fuse portion is configured to establish a discontinuity between the first portion and the second portion during a hard short event.

A battery pack includes a battery pack housing, a plurality of battery pack terminals, and a plurality of battery cells supported within the battery pack housing. At least one battery cell includes a battery cell terminal. The battery pack also includes a compound fuse electrically coupled between the battery cell terminal of the at least one battery cell and at least one battery pack terminal. The compound fuse comprises a first material and a second material that has a lower melting point than the first material. The compound fuse includes a first portion electrically coupled to the battery cell terminal, a second portion electrically coupled to the at least one battery pack terminal, and a fuse portion that connects the first portion to the second portion. The fuse portion is configured to establish a discontinuity between the first portion and the second portion during a hard short event.

A cylindrical secondary battery may have an insulation layer formed in a region in which the top cap and the first gasket are coupled to each other. The insulation layer may include a ceramic material and a binder. The secondary battery is designed so that, when an external electrical conductive object is electrically connected directly to a positive electrode and a negative electrode of the secondary battery, an electrode tab of the secondary battery is broken as quickly as possible.

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 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.

Disclosed are a protection device for a secondary battery in which two flux cores are embedded in a fusible element to be separated from each other and be disposed adjacent to fusible element electrodes on both sides of the fusible element so that it is not necessary to apply a flux onto the surface of the fusible element, a manufacturing process for uniformly applying the flux is eliminated to significantly reduce a manufacturing cost, a first flux core and a second flux core embedded in the fusible element attract fused matters of the fusible element toward the fusible element electrodes on both sides of the fusible element when the fusible element is fused, to improve the fusing performance of the fusible element, and a current path is reliably cut off after the fusible element is fused.

Disclosed are a protection device for a secondary battery in which two flux cores are embedded in a fusible element to be separated from each other and be disposed adjacent to fusible element electrodes on both sides of the fusible element so that it is not necessary to apply a flux onto the surface of the fusible element, a manufacturing process for uniformly applying the flux is eliminated to significantly reduce a manufacturing cost, a first flux core and a second flux core embedded in the fusible element attract fused matters of the fusible element toward the fusible element electrodes on both sides of the fusible element when the fusible element is fused, to improve the fusing performance of the fusible element, and a current path is reliably cut off after the fusible element is fused.