Hitachi, Ltd.

Hitachi Maxell, Limited

Yuki Okuda

Norio Iwayasu

Katsunori Nishimura

Hidetoshi Honbo

Jinichi Imahashi

Jinbao Zhao

Hidetoshi Honbou

An overcharge inhibitor is provided which increases an internal resistance of a battery, being electropolymerized by reaction with a positive electrode at a high potential in overcharging. The overcharge inhibitor is produced by using a polymer containing a polymerizable monomer as a repeating unit. The polymerizable monomer has a functional group that is electropolymerized at a potential of 4.3 to 5.5 V based on a lithium metal reference.

Overcharge inhibitor, and nonaqueous electrolyte solution and secondary battery using the same

Provided is a lithium ion rechargeable battery less suffering from swelling even when stored at high temperatures. Disclosed are a cathode active material, a cathode for a lithium ion rechargeable battery using the cathode active material, and a lithium ion rechargeable battery using the cathode. The cathode active material includes particles, each of the particles including a cathode material capable of intercalating and deintercalating lithium ions, and a film formed on at least part of surfaces of the particles. The film includes a compound represented by Chemical Formula (1). Examples of the compound represented by Chemical Formula (1) include lithium squarate and dilithium squarate. Preferably, the lithium ion rechargeable battery is a prismatic battery.

Cathode active material and lithium ion rechargeable battery using the material

A polymer electrolyte fuel cell comprises a fuel cell stack and a humidifier. The fuel cell stack includes plural cells in which each cell has a pair of electrodes and a proton-conductive electrolyte membrane arranged between the pair of electrodes, wherein an oxidant gas or a fuel gas passes through the humidifier before being fed to the fuel cell stack, and wherein a wet gas containing water or water vapor also passes through the humidifier. In the fuel cell, the humidifier includes a porous separating layer and a hydrophilic water-releasing layer, wherein the separating layer is configured to separate the wet gas from the oxidant gas or the fuel gas in the humidifier, and wherein the hydrophilic water-releasing layer is disposed in a side of the oxidant gas or the fuel gas to the separating layer in the humidifier.

Polymer electrolyte fuel cell system

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Hitachi, Japan

Yuki Okuda