A battery having the electrodes of multiple battery cell types are interleaved to prevent thermal runaway by cooling a shorted region between electrodes. The electrodes of each of the battery cell types with a first polarity share a pair of the common electrodes having a second polarity. The electrodes of the multiple battery cell types and the multiple common electrodes are interleaved such that if the electrodes of the multiple battery cell types and the adjacent common electrodes of one or more battery cell types short together, the current within the shorted battery cells is sufficiently small to prevent thermal runaway and the electrodes of the adjacent cells of the other battery cell types of the first polarity and the common electrodes of the second polarity not having short circuits provide heat sinking for the heat generated by the short circuit to prevent thermal runaway.

Supercapacitor structures are provided which include, for example: one or more layers of supercapacitors; and one or more contact tabs. The one or more contact tabs electrically contact and extend outward from the supercapacitor structure to facilitate electrical connection to the supercapacitor structure, and the one or more contact tabs include a multi-contact tab. The multi-contact tab is configured and sized with multiple contact locations which are disposed external to the supercapacitor structure. Various supercapacitor structures are provided, including one supercapacitor structure with a shared C-shaped current collector, and another supercapacitor structure with stacked supercapacitors. One or more additional multi-contact tabs may also extend from the supercapacitor structure(s) and distribute the same or a different capacitor voltage than the multi-contact tab.

A power storage device that includes an electrolyte retaining layer between a first internal electrode and a second internal electrode. The electrolyte retaining layer retains an electrolyte. The first internal electrode has a first current collector and a first active material layer. The first active material layer is on a surface of the first current collector, which is closer to the second internal electrode. The second internal electrode has a second current collector and a second active material layer. The second active material layer is on a surface of the second current collector, which is closer to the first internal electrode. At least one of the electrolyte retaining layer, first active material layer, and second active material layer is exposed at the first and second end surfaces of the power storage device.

A capacitor includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The positive electrode includes a positive electrode current collector and a positive electrode active material held on the positive electrode current collector. The positive electrode active material contains activated carbon. The activated carbon has a carboxyl group, and an amount of desorption of carboxyl group per unit mass of the activated carbon is 0.03 mol/g or less when the activated carbon is heated with a temperature increase from 300 C. to 500 C. The capacitor has an upper-limit voltage V.sub.u for charging and discharging. The upper-limit voltage V.sub.u of a lithium-ion capacitor is 4.2 V or more. The upper-limit voltage V.sub.u of an electric double-layer capacitor is 3.3 V or more.

A capacitor includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The positive electrode includes a positive electrode current collector and a positive electrode active material held on the positive electrode current collector. The positive electrode active material contains activated carbon. The activated carbon has a carboxyl group, and an amount of desorption of carboxyl group per unit mass of the activated carbon is 0.03 mol/g or less when the activated carbon is heated with a temperature increase from 300 C. to 500 C. The capacitor has an upper-limit voltage V.sub.u for charging and discharging. The upper-limit voltage V.sub.u of a lithium-ion capacitor is 4.2 V or more. The upper-limit voltage V.sub.u of an electric double-layer capacitor is 3.3 V or more.

There is provided a laminated-type battery prevented from short-circuit between a positive electrode and a negative electrode, suppressed in a local increase in the thickness of the battery, and high in electric properties and the reliability. The laminated-type battery includes a battery element having at least two sheets of first-polarity electrodes each laminated with a second-polarity electrode with a separator therebetween, wherein the first-polarity electrode includes an electrode section having an active material layer formed on a current collector, a lead section having no active material layer formed on the current collector, and an insulating layer disposed over from the active material layer to an active material layer-non-formed region on a boundary region of the electrode section and the lead section, wherein the insulating layer of the one first-polarity electrode and the insulating layer of the another first-polarity electrode are formed at least partly on different positions as viewed in the lamination direction.

Provided herein is an electrochemical cell designed for high current discharge, which includes a cathode strip, an anode strip, and at least two separator strips, being longitudinally stacked to form an electrodes set that is folded into segments.

A power storage device including: an electrode body including a positive electrode and a negative electrode being wound with a separator interposed therebetween; and a negative electrode current collector plate joined to the negative electrode disposed at one end in an axial direction of the electrode body. The current collector plate includes a core material joint part extending in a radiation direction of the electrode body, and including a surface facing the negative electrode joined to the negative electrode in the axial direction, and eaves parts formed on both end parts in a circumferential direction of the core material joint part, and extending toward the negative electrode in the axial direction.

An electrochemical energy storage cell includes a first electrically insulating substrate and a first electrical conductor layer extending on an area of the first electrically insulating substrate, a second electrically insulating substrate and a second electrical conductor layer extending on an area of the second electrically insulating substrate, a first electrode layer composed of positive electrode material, a second electrode layer composed of negative electrode material, a first separator layer, a stacked arrangement of the layers: the first electrically insulating substratethe first electrical conductor layerthe first electrode layerthe first separator layerthe second electrode layerthe second electrical conductor layerthe second electrically insulating substrate, a first electrolyte enabling an ion flow between the electrode layers, an electrode region with the stacked arrangement of the electrode layers and a supercapacitor region, a second separator layer, a second electrolyte enabling an ion flow between the supercapacitor layers.