A method of forming a high energy density capacitor comprises depositing a first metal layer on a substrate, depositing a first layer of polarizable dielectric material comprised of a high K dielectric material on said first metal layer, and applying a momentary high voltage electric field of positive or negative polarity above said first layer of polarizable dielectric material forming an electret. The method further comprises depositing a second metal layer on said first layer of polarizable dielectric material, depositing a second layer of polarizable dielectric material comprised of a high K dielectric material onto said second metal layer, and applying a second momentary high voltage electric field of opposing polarity above said second layer of polarizable dielectric material to align dipoles of the second layer into one or more electrets that will oppose a main electric field created as the capacitor is charging. The first and second metal layers are shorted to ground prior to applying said first and second momentary high voltage electric fields.

A power storage system includes a plurality of power storage modules each including a plurality of cells that is layered perpendicularly to an installation plane and is electrically connected dries. The plurality of power storage modules is mounted on a frame. A plurality of conductive trays is aligned horizontally between the frame and the plurality of power storage modules and horizontally divides the plurality of power storage modules into a plurality of groups.

A power storage system includes a plurality of power storage modules each including a plurality of cells that is layered perpendicularly to an installation plane and is electrically connected dries. The plurality of power storage modules is mounted on a frame. A plurality of conductive trays is aligned horizontally between the frame and the plurality of power storage modules and horizontally divides the plurality of power storage modules into a plurality of groups.

There is provided a power storage device including: a power storage assembly; and a plurality of joined portions, each of the plurality of electrode plates including an electrode plate main body and a tab, the plurality of electrode plates being disposed such that the tabs are arranged in the stacking direction, the plurality of joined portions including a first joined portion configured to join the plurality of tabs to form a first bundle portion, and a second joined portion configured to join the plurality of tabs arranged in the stacking direction to form a second bundle portion, a part of the tabs in the first bundle portion and a part of the tabs in the second bundle portion being joined to the first joined portion and the second joined portion.

Provided is a method for manufacturing a laminated electrode body which is excellent in terms of productivity and production cost. The method for manufacturing a laminated electrode body disclosed herein includes the steps of: preparing a wound body having a flat portion and two curved portions by using a laminate formed of an elongated positive electrode, an elongated negative electrode, and an elongated separator that insulates the positive electrode and the negative electrode from each other; preparing an electrode laminate structure having two cut surfaces by cutting out and removing the two curved portions of the wound body; and removing active materials on the cut surfaces of the electrode laminate structure by spraying an inactive gas or electrically insulating particles onto the cut surfaces while applying, to the electrode laminate structure, a voltage of 25 V or more and less than a voltage causing a dielectric breakdown of the separator.

Provided is a supercapacitor comprising an anode, a cathode, an ion-permeable separator disposed between the anode and the cathode, and an electrolyte in ionic contact with the anode and the cathode, wherein at least one of the anode and the cathode contains multiple graphene sheets spaced by cellulosic nanofibers and has a specific surface area from 50 to 3,300 m.sup.2/g. Also provided is a process for producing an electrode for such a supercapacitor having a large electrode thickness, high active mass loading, high tap density, and exceptional energy density.

Provided is a bi-polar electrode for a battery, wherein the bi-polar electrode comprises: (a) a current collector comprising a conductive material foil (e.g. metal foil) having a thickness from 10 nm to 100 m and two opposed, parallel primary surfaces, wherein one or both of the primary surfaces is coated with a layer of graphene material having a thickness from 10 nm to 10 m; and (b) a negative electrode layer and a positive electrode layer respectively disposed on the two sides of the current collector, each in physical contact with the layer of graphene material or directly with a primary surface of the conductive material foil (if not coated with a graphene material layer). Also provided is a battery comprising multiple (e.g. 2-300) bipolar electrodes internally connected in series. There can be multiple bi-polar electrodes that are connected in parallel.

A separator for an electrochemical element suitable extends the service life of an electrochemical element under high temperature conditions. This separator for an electrochemical element is disposed between a pair of electrodes and is for separating the two electrodes from each other and retaining an electrolytic solution, wherein the separator contains a cellulose-based fiber, and the limiting viscosity of the separator as measured by the measurement method specified in JIS P 8215 is in a range of 150-500 ml/g.

A separator for an electrochemical element suitable extends the service life of an electrochemical element under high temperature conditions. This separator for an electrochemical element is disposed between a pair of electrodes and is for separating the two electrodes from each other and retaining an electrolytic solution, wherein the separator contains a cellulose-based fiber, and the limiting viscosity of the separator as measured by the measurement method specified in JIS P 8215 is in a range of 150-500 ml/g.

A separator for an electrochemical device is provided. The separator comprises a porous substrate having a plurality of pores, and a porous coating layer positioned on at least one surface of the porous substrate, the porous coating layer including a plurality of inorganic particles and a binder polymer positioned on a whole or a part of the surface of the inorganic particles to connect the inorganic particles with one another and fix the inorganic particles, wherein the binder polymer comprises a first binder polymer and a second binder polymer. The first binder polymer has an electrolyte uptake of 80-165%, and the second binder polymer has an electrolyte uptake of 20-40%. An electrochemical device including the separator is also disclosed.