A stack-type electrode assembly includes a lowermost electrode in a lowermost portion of the electrode assembly; an uppermost electrode in an uppermost portion of the electrode assembly; at least one unit stack between the lowermost electrode and the uppermost electrode, the at least one unit stack comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode; and a plurality of separators between the lowermost electrode and unit stack, between the unit stacks, and between the unit stack and the uppermost electrode.

The main object is to provide a novel material with excellent charge and discharge characteristics, such as a high utilization rate of a positive electrode, a high capacity, and good cycle characteristic, in which the material is a compound containing as the major component lithium sulfide useful as a cathode active material for lithium secondary batteries. The invention provides a lithium sulfide-iron-carbon composite containing lithium, iron, sulfur and carbon as constituent elements, with lithium sulfide (Li.sub.2S), as the main phase, having a crystallite size of 50 nm or less as calculated from the half width of the diffraction peak based on the (111) plane of Li.sub.2S as determined by X-ray powder diffraction.

A separator for a bobbin-style electrochemical cell is inserted into an interior opening within a ring-shaped cathode in an electrochemical cell can. An expansion force is then applied to an interior surface of the separator to press the separator against the interior walls of the cathode. A tool may then remove various creases and/or wrinkles in the separator and/or may then heat seal at least a portion of the tubular walls of the separator to minimize the void space between the separator and active material (e.g., cathode and/or anode) within the electrochemical cell.

A method for forming an electrical connection to a microscale electrically conductive fibre material electrode element, such as a carbon fibre electrode element of a Pb-acid battery, comprises pressure impregnating into the fibre material an electrically conductive lug material, such as molten Pb metal, to surround and/or penetrate fibres and form an electrical connection to the fibre material and provide a lug for external connection of the electrode element. Other methods of forming a lug for external connection are also disclosed.

Cathode active materials for alkaline cells are disclosed. In particular, the cathode structures encompass conductive carbons introduced to the cathode so as to have a specific spatial orientation and/or a multi-carbon structure. The overall intent is to leverage the conductor(s) provided to the cathode structure to improve electronic and ionic conductance and, by extension, improve battery discharge performance.

The present disclosure is intended to reduce the resistance of a high-loading electrode, to improve the impregnation ability of an electrolyte and thus to improve the rate characteristics of a battery. The present disclosure provides a method for manufacturing an electrode which includes the steps of: a coating step in which electrode active material slurry containing an electrode active material, a binder and a solvent is applied to at least one surface of an electrode current collector; a drying step in which the electrode current collector coated with the electrode active material slurry is introduced continuously to a drying system to dry the coated electrode active material slurry; and a rolling step in which the dried electrode active material slurry is rolled, wherein the coating step includes applying the electrode active material slurry in a loading amount of 500 mg/cm.sup.2 to 1500 mg/cm.sup.2, and the method further comprises a pattern forming step carried out simultaneously with the drying step and forming a plurality of longitudinal patterns on the surface of the coated electrode active material slurry.

A system for controlling a thickness of an electrode includes a first press configured to accommodate an electrode powder consecutively supplied and press the electrode powder into an electrode sheet in the form of a film, a second press disposed downstream of the first press and configured to receive the electrode sheet and press the received electrode sheet, a measuring device disposed downstream of the second press and configured to measure a thickness of the electrode sheet in real time, and a controller configured to change an operating condition of the first press or an operating condition of the second press based on thickness information measured by the measuring device.

A free-standing electrode film may comprise an electrode active material and a composite binder comprising polytetrafluoroethylene (PTFE) and polyvinylpyrrolidone (PVP). An electrode for an energy storage device may comprise a current collector and a film on the current collector, the film including an electrode active material and a composite binder comprising PTFE and PVP. A method of manufacturing a free-standing electrode film may comprise preparing a mixture including an electrode active material and a composite binder, the composite binder comprising PTFE and one or more additional binders selected from the group consisting of PVP, polyvinylidene fluoride (PVDF), polyethylene oxide (PEO), and carboxymethylcellulose (CMC). The method may further comprise adding a solvent to the mixture, subjecting the mixture to a shear force, and, after the solvent has been added and the mixture has been subjected to the shear force, pressing the mixture into a free-standing film.

An electrode disclosed here includes a surface part of an electrode active material layer has a plurality of first grooves extending in a width direction of the electrode current collector and at least one second groove extending in a longitudinal direction of an electrode current collector. The first groove is formed to be continuous from one end to another end. Here, a region in which the first groove and the second groove are formed is uniformly divided into three layers, which are an upper layer, an intermediate layer and a lower layer, in a thickness direction from the surface of the electrode active material layer to the electrode current collector, and when electrode densities (g/cm.sup.3) of the upper layer, the intermediate layer and the lower layer of the groove are d.sub.1, d.sub.2, and d.sub.3, respectively, a relationship of 0.8<(d.sub.1/d.sub.3)<1.1 is satisfied.

Various embodiments disclosed relate to novel methods of fabricating 3-D Li ion batteries using direct nanoimprint lithography. The present invention includes methods of fabricating high surface area electrodes, including imprint patterning of high aspect ratio parallel grating style electrodes. The method includes coating a substrate with an ink containing nanoparticles and subsequently annealing the ink into a desired pattern.