Le portable électronique (document en anglais)

Portable electronic equipment is moving toward increasing compactness and light weight, and we are on the threshold of the age of wearable equipment. In such circumstances the rechargeable batteries which power such equipment play an increasingly vital role, and in addition to demands for reduced size and weight, there are now also requests for performance necessary to support the sophisticated functions of modern equipment. In response to these needs, Sony has conducted development based on entirely novel concepts, and in 1991 released the world's first commercial lithium ion rechargeable battery product. In addition to a high energy density, this battery also offered excellent low-temperature characteristics, load characteristics and cycle characteristics. As a result, it quickly became an indispensable source of power for audio and video equipment, personal computers, portable telephones, and other portable equipment. And, Sony development efforts are advancing steadily toward the next generation of products, targeting new type lithium ion rechargeable batteries which are easier to use such as "polymer batteries" with polymerized electrolyte. 1–2Features 1）Energy densities are high; the US18650 size attains the energy density per volume of approx. 440 Wh/l and the energy density per weight of approx. 160 Wh/kg. 2）Voltages are high, with average operating voltages at 3.6 V for hard carbon batteries and 3.7 V for graphite batteries; these are approximately three times the cutoff voltage of Ni-Cd and Ni-MH batteries. 3）Charge/discharge cycle characteristics are excellent; batteries can be put through 500 or more cycles. 4）Self-discharge is minimal, at under 10% per month. 5）There is no memory effect such as that in Ni-Cd and Ni-MH batteries. 6）Remaining capacity can easily be indicated using the discharge curve. 7）Carbon material, rather than metallic lithium or lithium alloy, is used as the anode material. The lithium ion state is maintained over a wide range of operating conditions, for excellent safety. 8）In accordance with using gel polymer electrolyte, laminated film can be used to outer equipment and,“thin”and“light”lithium ion rechargeable battery was achieved.＊Thickness is approx. 2.5mm at present. In future, achievement of 1mm or less is possible.＊According to using special gel polymer electrolyte, it become possible to supply no leak of the electrolyte and extremely high safety batteries.＊Development of big footprint cells become possible (xx5385 series like as 325385 etc.). That was impossible to usual lithium ion batteries. 1–3Origin of battery name In these batteries, carbon material is used in the anodes and a metal oxide material containing lithium is used in the cathodes; lithium ions migrate between the two electrodes via an organic electrolyte. By designing these batteries in accordance with the reversible capacity of the carbon material, lithium does not exist in the metallic state during either the charging or discharging processes. In order to differentiate these batteries from those using metallic lithium or lithium alloy in the anode, we designated these devices lithium ion rechargeable batteries. 1-2 1-3 7

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