Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Sanyo Electric Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Tatsuhiko Suzuki

Yoshitaka Dansui

Hiroki Takeshima

Hideki Kasahara

Kohji Yuasa

Fumio Kato

Hidekazu Hiratsuka

Kaoru Nagata

Futoshi Tanigawa

Tsutomu Nishioka

Akira Nagasaki

Takeshi Yao

Tadao Kimura

Masumi Katsumoto

Hajime Konishi

Motohide Masui

A positive electrode active material for nonaqueous electrolyte secondary batteries, which has high energy density and excellent cycle characteristics. A positive electrode active material for nonaqueous electrolyte secondary batteries of the present invention is represented by general formula LiNiCoMO(wherein M represents at least one element selected from among metal elements, 0.3&#x2264;x&#x3c;1.0 and 0&#x3c;y&#x2264;0.5) and is configured of particles, each of which is an aggregate of crystallites. Each particle has a compressive breaking strength of from 200 MPa to 500 MPa (inclusive), and the crystallite diameter in the vector direction of the particle is from 100 nm to 300 nm (inclusive).

Positive electrode active material for nonaqueous electrolyte secondary batteries, and nonaqueous electrolyte secondary battery

Disclosed is a charging method for one or more non-aqueous electrolyte secondary batteries by n steps of constant-current charging processes, where n is an integer equal to or greater than 2. The n steps include: (1) charging the secondary batteries at a current Ic(k) until a charge voltage per one battery reaches a voltage Ec(k), where k is an integer equal to or greater than 1 and equal to or smaller than n&#x2212;1; and (2) when the charge voltage per one battery reaches the voltage Ec(k), charging the secondary batteries at a current Ic(k+1) smaller than the current Ic(k) until the charge voltage per one battery reaches a voltage Ec(k+1) higher than the voltage Ec(k), in which (3) the currents Ic(k) and Ic(k+1) are set according to frequency of use or number of charge and discharge cycles of the secondary batteries.

Charging method for non-aqueous electrolyte secondary battery, and battery pack

In the present method, a non-aqueous electrolyte secondary battery is charged by repeating n+1 times a constant current charge and a subsequent constant voltage charge, where n is an integer of 1 or more. (1) An ncharge comprises charging the secondary battery at a current Ic(n) to a voltage Ec(n), and subsequently charging the secondary battery at the voltage Ec(n) until the current decreases from Ic(n) to Ic(n+1). (2) An (n+1)charge comprises charging the secondary battery at the current Ic(n+1) to a voltage Ec(n+1), and subsequently charging the secondary battery at the voltage Ec(n+1) until the current decreases from Ic(n+1) to Ic(n+2). Consequently, the charge time of the non-aqueous electrolyte secondary battery can be shortened while deterioration of the battery can be suppressed.

Charging method for non-aqueous electrolyte secondary battery by repeating a set of constant current charge and constant voltage charge and battery pack implementing the charging method

A secondary battery deterioration judging device is provided with an overdischarge detecting section for detecting the overdischarge of a secondary battery, the deterioration of which is to be judged, a computing section for integrating a value indicating the deterioration of the secondary battery while the overdischarge is detected by the overdischarge detecting section, and a judging section for judging a deterioration state of the secondary battery based on an integration value obtained by the computing section.

Secondary battery deterioration judging device and backup power supply

A battery life predicting device and a battery life predicting method capable of accurately predict the lifetime of storage batteries are provided. The expected lifetime value selecting unitselects, as an expected lifetime value, a lifetime value that corresponds to the load power applied by the storage battery during discharge and the ambient temperature of the location where the storage batteryis installed while referring to the lifetime data stored in the lifetime data storing unit, the first diminution in lifetime calculating unitcalculates the first diminution in lifetime based on a natural logarithm function that takes the time obtained by converting the number of discharge cycles of the storage batteryas a variable, the second diminution in lifetime calculating unitcalculates the second diminution in lifetime from the mean value of the storage battery temperatures during charging, discharging or an idle state, the ambient temperature and the time elapsed after the installation of the storage battery, and the remaining lifetime value calculating unitcalculates the remaining lifetime value by subtracting the first diminution in lifetime and the second diminution in lifetime from the expected lifetime value.

Battery life predicting device and battery life predicting method

Data indicating a relationship of life of a battery to a value of load power applied to the battery in discharge and environmental temperature of a place where the battery is installed are prepared beforehand. Next, the load power and the environmental temperature when the battery is discharged are measured, and then a life value corresponding to these measured values is selected from the data so as to be set as an expected life value. Next, a first life reduction amount is calculated from a natural logarithmic function with the number-of-discharges as a variable, and the difference between the expected life value and the first life reduction amount is set to a remaining life value, on the basis of which the life of the nickel-hydride battery is determined. By this method, the life of the nickel-hydride battery as a backup power source can be accurately determined, while correction based on phenomena unique to the nickel-hydride battery is performed.

Nickel-hydride battery life determining method and life determining apparatus

A nickel metal hydride storage battery having an excellent charging efficiency at high temperatures is provided by using a positive electrode comprising nickel hydroxide particles and at least one rare earth compound obtainable by treating a rare earth oxide with an aqueous alkaline solution and an oxidizing agent.

Method of preparing a nickel positive electrode active material

An alkaline storage battery using positive electrodes comprising an active material containing nickel hydroxide particles and a rare earth element or a compound thereof containing or mixed with 0.1-100 ppm of Fe or an Fe compound based on the rare earth element or the compound thereof is provided.

Alkaline storage battery and positive electrode used for the alkaline storage battery

A nickel-metal hydride secondary battery includes positive electrodes including nickel hydroxide, negative electrodes including a hydrogen-absorbing alloy, separators and an alkaline electrolyte. The positive electrode includes a compound silicate. By employing the above construction, the compound silicate reacts with Mn or Al which dissolves out from the negative electrode to inhibit deterioration of electrochemical characteristics of the battery, and thus the life of the battery can be prolonged.

Nickel-metal hydride secondary battery comprising a compound silicate

The present invention provides alkaline storage batteries high in energy density and excellent in overdischarge resistance, and, besides, less in decrease of capacity even if charging and discharging cycle is repeated at high temperatures. There is used a positive electrode comprising a foamed nickel substrate having the number of pores of 80-160 pores/inch (PPI ) and a thickness of skeleton of 30-60 &mgr;m in which spherical nickel hydroxide solid solution particles having an average particle size of 5-20 &mgr;m and a cobalt oxide conductive agent having an average particle size of 1 &mgr;m or less and mainly composed of &ggr;-cobalt oxyhydroxide having a cobalt valence of higher than 3.0 are held and the total occupying ratio of the spherical nickel hydroxide solid solution particles and the cobalt oxide conductive agent based on the whole electrode plate is in the range of 75-85 vol %.

Non-sintered positive electrode for alkaline storage battery and alkaline storage battery using the same

The present invention provides a positive electrode material for alkaline storage batteries which has high energy density and causes little capacity reduction even when a charge/discharge cycle is repeated at high temperatures. The positive electrode material for alkaline storage batteries of the present invention comprises nickel hydroxide particles and a layers of cobalt oxide coating the nickel hydroxide particles. A valence of cobalt of the cobalt oxide is greater than 3.0, and the cobalt oxide contains sodium ions or potassium ions inside the crystal and further fixes lithium hydroxide or lithium ions.

Positive electrode material for alkaline storage battery and method of producing the same

A method for managing a back-up power source capable of maintaining the discharge capacity of a nickel metal-hydride storage battery for a long-term at a low cost, and is suitable for the management of the back-up power source for the guidance lights, the emergency lights, the information telecommunication systems, and the like is disclosed. The present invention provides a method for managing the back-up power source which uses a nickel metal-hydride storage battery including a positive electrode mainly consisting of nickel oxide, a negative electrode mainly consisting of a hydrogen storage alloy, a separator and an alkaline electrolyte, wherein an intermittent charge is performed on the nickel-metal hydride storage battery, comprising: calculating a self-discharge quantity of the nickel-metal hydride storage battery during idle period of the intermittent charge on the basis of a temperature of the nickel-metal hydride storage battery at the idling; and controlling the charging of the nickel-metal hydride storage battery on the basis of the obtained self-discharge quantities.

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Osaka, Japan

Tatsuhiko Suzuki