Hitachi High-tech Corporation

Sumitomo Osaka Cement Co., Ltd.

Hitachi, Ltd.

Katsutoshi Kondo

Toru Kouno

Emha Bayu Miftahullatif

Hiroya Fujimoto

Yutaka Ueda

Satoru Akiyama

Junichiro Ichikawa

Eiji Murakami

Kiyotaka Nakano

Yuki Kugimoto

Yumi Murata

Ryo Wakabayashi

Ichikawa Junichiro

The objective of the present invention is to provide a technology capable of estimating a battery condition in conjunction with charging/discharging operations of a battery, without employing dedicated equipment for estimating the condition of the battery. A battery management device according to the present invention identifies a first period and a subsequent second period in a rest period after a battery finishes discharging or charging, and uses an output voltage difference in the second period to estimate the condition of the battery (see FIG.).

Battery management device, and electric power system

The purpose of the present invention is to provide a technique capable of accurately estimating SOH without relying on a calculation standard of a capacity change when obtaining the SOH. The battery state estimation device according to the present invention specifies a first period and a second period in a stop period after a battery has completed charging or discharging and refers to the relationship between an estimated value of the state of health of the battery and a measured value of the state of health, thereby estimating the measured value, said estimated value being obtained using the difference between the output voltages in the second period (refer to FIG.A).

Battery state estimation device and power system

An object of the invention is to provide a control technique capable of connecting a storage battery to a DC bus via a DC/DC converter and controlling charging and discharging of the storage battery by the DC/DC converter. A DC grid system according to the invention calculates a voltage command value of a DC bus using a present voltage of a storage battery and a target voltage of the storage battery, and provides the voltage command value as a command value for each of an AC/DC converter and a DC/DC converter (see FIG.).

DC grid system, control device, and control method

An optical waveguide device including an optical waveguide substrate that has an electro-optic effect, is a crystal having anisotropy in thermal expansion rate, has a thickness set to 10 &#x3bc;m or lower, and includes an optical waveguide and a holding substrate that holds the optical waveguide substrate, the optical waveguide substrate and the holding substrate being joined to each other, in which the holding substrate is formed of a crystal having a lower dielectric constant than the optical waveguide substrate and having anisotropy in thermal expansion rate, and the optical waveguide substrate and the holding substrate are joined to each other such that differences in thermal expansion rate between the optical waveguide substrate and the holding substrate become small in different axial directions on a joint surface.

Optical waveguide device

To provide an optical element in which an electrode is directly formed on an LN substrate, and a drift phenomenon is suppressed. In an optical element including: a substrate made of lithium niobate crystals; and an electrode disposed on the substrate, the substrate and the electrode are in direct contact with each other, and as a contact metal disposed on a surface of the electrode where the electrode is in contact with the substrate, a metal material whose standard enthalpy of formation per coordinate bond upon oxidation is greater than a standard enthalpy of formation per coordinate bond of niobium pentoxide is used.

Optical element

Growing community of inventors

Tokyo, Japan

Katsutoshi Kondo