Abstract: A power storage device includes power storage cells that includes a positive electrode, a negative electrode, a separator, and an accommodation chamber accommodating a liquid electrolyte in a liquid-tight manner. The power storage device includes a cell stack in which the power storage cells are stacked in series. A side surface of the cell stack is covered with a seal portion made of a plastic. The terminal positive electrode current collector and the terminal negative electrode current collector located in the outermost layer of the cell stack are made of a high thermal conductivity material having a thermal conductivity greater than or equal to 100 W/(m·K). The power storage device includes a positive electrode cooling unit, which cools the terminal positive electrode current collector, and a negative electrode cooling unit, which cools the terminal negative electrode current collector. The liquid electrolyte contains an oxalate compound.

Abstract: A power storage device includes power storage cells that includes a positive electrode, a negative electrode, a separator, and an accommodation chamber accommodating a liquid electrolyte in a liquid-tight manner. The power storage device includes a cell stack in which the power storage cells are stacked in series. A side surface of the cell stack is covered with a seal portion made of a plastic. A terminal positive electrode current collector and a terminal negative electrode current collector located in the outermost layer of the cell stack are made of a high thermal conductivity material having a thermal conductivity greater than or equal to 100 W/(m·K). The power storage device includes a positive electrode cooling unit, which cools the terminal positive electrode current collector, and a negative electrode cooling unit, which cools the terminal negative electrode current collector. The liquid electrolyte contains an ester compound.

Abstract: Provided are an electrolytic solution suitable for a lithium ion secondary battery that includes a positive electrode which has a positive electrode active material having an olivine structure, and includes a negative electrode having graphite as a negative electrode active material, and a superior lithium ion secondary battery having the electrolytic solution. The lithium ion secondary battery includes: a positive electrode that includes a positive electrode active material having an olivine structure; a negative electrode having graphite as a negative electrode active material; and an electrolytic solution. The electrolytic solution contains LiPF6, a cyclic alkylene carbonate selected from ethylene carbonate and propylene carbonate, methyl propionate, and an additive that starts reductive degradation at a potential higher than a potential at which the above components of the electrolytic solution start reductive degradation.

Abstract: A nonaqueous electrolyte secondary battery includes: an electrode body that includes a positive electrode and a negative electrode; a battery case that accommodates the electrode body and a nonaqueous electrolytic solution; an external connection terminal that is electrically connected to one electrode of the positive electrode and the negative electrode; and a current interrupt device that interrupts a conductive path, through which the electrode and the external connection terminal are electrically connected to each other, when an internal pressure of the battery case exceeds a predetermined value. The positive electrode includes a positive electrode current collector and a positive electrode mixture layer that contains a positive electrode mixture. When a ratio of an actual capacity to a nominal capacity is 95% or higher, an amount of fluorine contained per 1 mg of the positive electrode mixture is 0.15 ?mol to 0.20 ?mol.

Abstract: Providing a silicon-containing material having a novel structure being distinct from the structure of conventional silicon oxide disproportionated to use. A silicon-containing material according to the present invention includes at least the following: a continuous phase including silicon with Si—Si bond, and possessing a bubble-shaped skeleton being continuous three-dimensionally; and a dispersion phase including silicon with Si—O bond, and involved in an area demarcated by said continuous phase to be in a dispersed state.

Abstract: An electricity storage device includes an electrode assembly, a case, a safety valve, and a cover member. The case accommodates the electrode assembly. The safety valve is arranged in the case and opens to discharge gas out of the case when an inner pressure of the case exceeds a release pressure. The cover member is arranged in the case opposing the safety valve and includes a flow passage for the gas.

Abstract: A lithium ion secondary battery (100) includes a case (10), an electrode assembly (20), a first metal plate (12), a second metal plate (14), and an insulating member (16). The electrode assembly (20) includes a positive electrode (30), a negative electrode (40), and a separator (50). The first metal plate (12) is electrically connected to the positive electrode (30). The second metal plate (14) is electrically connected to the negative electrode (40). The first metal plate (12) is thicker than a positive electrode metal foil (30B). The second metal plate (14) is thicker than a negative electrode metal foil (40B). When the thickness of the first metal plate (12) is designated as D1, and the thickness of the second metal plate (14) is designated as D2, the relationship: 1<D1/D2<2 is satisfied.

Abstract: An electricity storage device includes an electrode assembly, a case, a safety valve, and a cover member. The case accommodates the electrode assembly. The safety valve is arranged in the case and opens to discharge gas out of the case when an inner pressure of the case exceeds a release pressure. The cover member is arranged in the case opposing the safety valve and includes a flow passage for the gas.

Abstract: Providing a silicon-containing material having a novel structure being distinct from the structure of conventional silicon oxide disproportionated to use. A silicon-containing material according to the present invention includes at least the following: a continuous phase including silicon with Si—Si bond, and possessing a bubble-shaped skeleton being continuous three-dimensionally; and a dispersion phase including silicon with Si—O bond, and involved in an area demarcated by said continuous phase to be in a dispersed state.