In a capacitor using a capacitor element having an anode foil and a cathode foil wound with a separator interposed between the anode foil and the cathode foil, the separator includes a low insulation part having a low insulation function between the anode foil and the cathode foil, and the low insulation part may be included within a range of 90% in a central portion in a height direction of the capacitor element and within a range of 5 to 90% in a diametrical direction from the center of the capacitor element.

In a capacitor using a capacitor element having an anode foil and a cathode foil wound with a separator interposed between the anode foil and the cathode foil, the separator includes a low insulation part having a low insulation function between the anode foil and the cathode foil, and the low insulation part may be included within a range of 90% in a central portion in a height direction of the capacitor element and within a range of 5 to 90% in a diametrical direction from the center of the capacitor element.

A capacitor bank which has a plurality of capacitor units, in which each capacitor has a plurality of electrical capacitor elements, and the capacitor units are divided into a plurality of groups of capacitor units. The arrangement has a plurality of group monitoring units, with one of the group monitoring units associated with each group of capacitor units. At least one of the group monitoring units is configured so that it monitors the respective group of capacitor units for a failure of a capacitor element in one of the capacitor units of the group and, when such a failure of a capacitor element is detected, transmits data which describe this failure of the capacitor element to a monitoring receiver.

A method for monitoring one or more characteristics of an ultracapacitor is provided. The method includes obtaining a plurality of voltage measurements. Each of the voltage measurements can be obtained sequentially at one of a plurality of intervals. Furthermore, each of the voltage measurements can be indicative of a voltage across the ultracapacitor. The method can include determining an actual voltage step of the ultracapacitor based on two consecutive voltage measurements of the plurality of voltage measurements. The method can further include determining whether the actual voltage step exceeds a threshold voltage step of the ultracapacitor. Furthermore, in response to determining the actual voltage step exceeds the threshold voltage, the method can include providing a notification associated with performing a maintenance action on the ultracapacitor.

A temperature-sensitive battery connector is disclosed. The connector can include a connector body and at least one conductor mounted to the connector body and configured to convey a current signal used to measure voltage from a battery pack or battery cell to a battery management system (BMS). The connector can include a thermal switching device mounted to the connector body and thermally coupled to a terminal of a battery pack or a battery cell. The thermal switching device can be configured to provide an overtemperature signal to the BMS by changing or interrupting a current conducted by at least one conductor when a temperature of the battery pack or battery cell exceeds a threshold temperature.

A rechargeable battery is provided with a pressure release valve and a current interruption mechanism. The current interruption mechanism includes a deformation plate. When the internal pressure of the case reaches an interruption activation pressure, the deformation plate receives the internal pressure and is deformed to break a conducting portion. In the current interruption mechanism, a pressure that is set for maintaining the sealing at the contact portion between the deformation plate and a negative electrode conductor is defined as a sealing portion withstanding pressure, and the pressure that is set for maintaining the shape of the case is defined as a case withstanding pressure. The pressure for activating the pressure release valve is defined as a valve activation pressure. In this case, the sealing portion withstanding pressure and the valve activation pressure are set higher than the interruption activation pressure and lower than the case withstanding pressure.

An energy storage device includes: a casing 30 having an opening; an energy storage element 20 housed in the casing 30; a lid plate 40 mounted in the opening of the casing 30; a positive electrode terminal member 100 and a negative electrode terminal member 71 integrally fixed to the lid plate 40 in an insulation state by an insulating synthetic resin; a positive electrode current collector 60P configured to electrically connect the energy storage element 20 and the positive electrode terminal member 100 to each other; and a negative electrode current collector 60N configured to electrically connect the energy storage element 20 and the negative electrode terminal member 71 to each other, wherein an easy-to-break portion 65 is formed on at least either one of the positive electrode terminal member 100 or the positive electrode current collector 60P.

The electric storage device disclosed herein is a stacked type electric storage device. The electric storage device includes a separator insulating a first electrode from a second electrode. The electric storage device includes a first conductive path from a first electrode terminal to the first electrode, a second conductive path from a second electrode terminal to the second electrode, and a current interruption device disposed between the second electrode terminal and the second electrode, the current interruption device being configured to interrupt the second conductive path. The separator includes a first surface part covering the one surface of the first electrode, a second surface part covering the other surface of the first electrode, and a connection part connected to both the first and second surface parts. The connection part is disposed between the current interruption device and an end of the first electrode on a current interruption device side.

The electric storage device disclosed herein is a stacked type electric storage device. The electric storage device includes a separator insulating a first electrode from a second electrode. The electric storage device includes a first conductive path from a first electrode terminal to the first electrode, a second conductive path from a second electrode terminal to the second electrode, and a current interruption device disposed between the second electrode terminal and the second electrode, the current interruption device being configured to interrupt the second conductive path. The separator includes a first surface part covering the one surface of the first electrode, a second surface part covering the other surface of the first electrode, and a connection part connected to both the first and second surface parts. The connection part is disposed between the current interruption device and an end of the first electrode on a current interruption device side.

The present technology relates to an electrochemical device comprising a separation membrane having a dotted line, and a short circuit inducing member, and a method capable of evaluating safety under internal short circuit conditions by using the electrochemical device. When using the electrochemical device of the present invention, it is possible to easily evaluate safety under internal short circuit conditions without physical deformation of an energy storage apparatus.