A method of producing a lithium-ion battery includes filling at least one cell of the battery with an electrolyte followed directly with a first step of sealing the at least one cell and a second step of applying pulsating compression to the at least one cell during formation charging, the pulsating compression comprising alternating a first time period of applying a first compression force F.sub.1 greater than zero and a second time period of applying a second compression force F.sub.2, wherein F.sub.1>F.sub.2, and the formation charging includes a first charge of the battery.

Cathode materials for lithium ion batteries, lithium ion batteries incorporating the cathode materials, and methods of operating the lithium ion batteries are provided. The materials, which are composed of lithium iron oxides, are able to undergo reversible anionic and cationic redox reactions with no O.sub.2(g) generation.

A method for producing a nonaqueous electrolyte secondary battery, and a production system therefor, that allow forming a SEI film in a shorter time. The method includes assembly, initial charging, and high-temperature aging steps. At least one from the initial charging and the high-temperature aging has the following sub-steps: a step of performing an AC impedance measurement on the battery and, on the basis of the AC impedance measurement, calculating an ionic conductivity of an SEI film that is formed the surface of a negative electrode of the battery; and a step of determining whether the calculated ionic conductivity falls within a predetermined range or not, and terminating the initial charging step or the high-temperature aging step when the ionic conductivity falls within the predetermined range, and continuing the initial charging step or the high-temperature aging step when the ionic conductivity does not fall within the predetermined range.

Disclose herein is a degassing apparatus for a pouch including a body part. The degassing apparatus can include a lower mold placed on a bottom surface of the body part, an upper mold configured to press a top surface of the body part placed on the lower mold, and a cooling member. At least one of the lower mold or the upper mold is cooled by the cooling member to cool am electrolyte injected into the body part when the body part contacts the lower or upper molds. A method for degassing a pouch can include seating a body part of the pouch on a lower mold, pressing the pouch with an upper mold, cooling a body part to lower the temperature of an electrolyte in an electrode assembly of the pouch, and suctioning a gas by inserting a gas inhaler into a gas pocket part.

A manufacturing apparatus includes a chamber, a pressure reducing device, and a return pipe. The pressure reducing device is configured to reduce the pressure in the chamber. The return pipe includes a first opening, a conduit, and a second opening. The first opening and the second opening are respectively and independently open to the interior of the chamber. The first opening is connected to an exterior body. The conduit connects the first opening and the second opening. The conduit is configured to once draw gas in the exterior body out of the chamber when the pressure in the chamber is reduced, and return the drawn gas into the chamber.

Proposed is a method of manufacturing a secondary battery. The method includes inserting an electrode assembly into a pouch, injecting an electrolyte into the pouch and aging, charging the electrode assembly, degassing to discharge gas from the pouch, discharging the electrode assembly, and charging to a shipment charge level. Since an anode active material is added to an anode material of a secondary battery through the method, there is an effect of further enhancing the reliability of the secondary battery in the manufacturing method of the secondary battery.

One aspect of the present invention is an energy storage device including: a flattened electrode assembly formed by winding a belt-like electrode in a longitudinal direction thereof and including two curved surface portions and a flat portion located between the two curved surface portions; a case housing the electrode assembly; and a sheet-like member disposed between the electrode assembly and the case, in which when an inside of the case is in a negative pressure state, the electrode assembly is in a state of being pressed by the case with the sheet-like member interposed therebetween, and the sheet-like member is in contact only with the flat portion with respect to the electrode assembly.

Provided are a lithium-ion battery and a preparation method therefor. The preparation method comprises the steps of connecting a plurality of cells in series and/or in parallel and then sealing to obtain a module, with the cells being jelly-rolls or stacking-rolls. According to the preparation method, the process is simple, and a battery housing shell and a module housing are combined into a whole, thereby greatly reducing the cost. Moreover, in the design of battery, the battery is internally provided with a heating sheet of graphene, etc., so as to overcome the low-temperature bottleneck of the lithium-ion battery. The standardized battery directly achieves integrated manufacturing from jelly-rolls or stacking-rolls into a module, has the characteristics of a low cost, a high energy density, a wide temperature range, high safety and a long service life, and omits the post-manufacturing procedure for the module so as to reduce the production cost.

A method includes a step A of ultrasonic-joining stacked metal foils to each other and a step B of ultrasonic-joining all of the joined metal foils and a metal plate to each other after the step A. The step A is performed by transmitting ultrasonic vibrations to a horn with the stacked metal foils being interposed between the horn and an anvil and pressed. The step A includes a first joining step of solid-state-joining at least some metal foils of the stacked metal foils that are located near the horn to each other, and a second joining step of solid-state-joining all of the stacked metal foils to each other after the first joining step. The second joining step is performed within a joined region that is joined at the first joining step.

Disclosed is a battery module, which includes a plurality of battery cells stacked on each other, a module case configured to accommodate the plurality of battery cells, a thermal resin filled in the module case to cover electrode leads of the plurality of battery cells at least partially, a laser sensor provided to the module case to measure a filling length of the thermal resin, and a control unit configured to control filling of the thermal resin based on the filling length information measured by the laser sensor.