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 Tozawa's project management style was based on a range finding system employed by the Japanese Navy. By shooting three guns at once, all aiming at the same target, the chance that one of the guns will actually reach the target is greater. With this approach, the target is reached faster and more accurately. In the same manner, Tozawa decided to start several research efforts simultaneously using slightly different approaches to reach the target of developing a lithium rechargeable battery. In this way, time lost when pursuing a fruitless avenue of research was kept to a minimum. However, this approach required the investment of many resources, namely, engineers, equipment and money. To manage it all, Tozawa became the project leader. In this position, he could make decisions on where to make investments. He could also free the engineers to concentrate on their assignments without having to worry about taking responsibility. The official announcement for the project (as one directly under the supervision of Tozawa) was made in July 1987.
At first, six research projects dealing with different materials were endorsed. At monthly meetings, these were all evaluated and eliminated one by one. The team was going through a process of trial and error in search for the  dream battery. Finally, one of the research teams began rejoicing; We got it!
This newly developed lithium battery did not use potentially dangerous metallic lithium or lithium alloys. Instead, it employed a special ionic lithium alloy called lithium cobalt oxide for the positive pole and a carbon material for the negative pole. There was no danger of damage due to water, making the battery very safe. The number of cycles in a single battery exceeded 1000, one and a half times that of a nickel-cadmium rechargeable battery. The integrated energy volume or the amount of energy obtainable when used to its limit of 1,000 cycles, was four times that of a nickel-cadmium battery of a similar type, and the equivalent of approximately 1,300 non-rechargeable, alkaline manganese dioxide batteries. In addition to the long life span of the battery, its energy density and average operating voltage were three times that of nickel-cadmium batteries of a similar type. The Sony battery was named the lithium-ion rechargeable battery, and Tozawa became known as its Godfather.
The selection of materials for the poles and electrolyte solution of this powerful battery was the result of endless tests conducted by the project members. For example, there were various types of carbon compounds that could have been used for the negative pole, which would affect the battery's performance. The engineers in charge of materials development searched for a better material in order to find new carbon compounds.
However, there were several problems that needed to be solved prior to its announcement. Patents had to be obtained for the carbon compounds and the methods used to create the lithium-ion alloy. In addition, an application had to be filed in the US for the product to be excluded from the hazardous materials list. Tozawa and the engineers worked frantically to solve these problems as fast as possible.
Furthermore, a production plan for the battery was developed early on. These preparations were spearheaded by the Sony Energytec engineers and backed by the entire Sony Group to enable a smooth start for mass production. By the time the product announcement was being prepared in 1988, production facilities with the capacity to manufacture 100,000 units per month were installed at the Koriyama plant in Fukushima Prefecture.
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A sample of lithium-ion rechargeable batteries |
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The announcement was finally made in February 1990. Sample shipments began the same year, and mass production started from the following year. In September 1990, the Battery Business Group was founded within Sony. Koichi Tsunoda, then president of Sony Energytec, was appointed as its general manager, and efforts towards full-scale mass production were initiated.
When this battery was used to power the Sony CCD-TR1 8 mm camcorder, it received favorable reviews. As a result, competing battery manufacturers also began to produce lithium-ion batteries.
Once the potential of this high energy density, long-lasting and safe lithium-ion rechargeable battery was recognized, applications began to expand. Not only could it be used for camcorders, but it could also power other portable AV equipment, including CD players, compact LDC televisions sets, word processors, portable PCs, mobile cellular phones, PHS (Personal Handyphone System) units and other items. Soon, manufacturers began to advertise the use of lithium-ion storage batteries as a key selling point of their products. Having succeeded in developing the first lithium-ion battery, Sony today still maintains a high market share and is the leading company in the field.
For the development of the battery in April 1994, the Electrochemical Society of Japan awarded Sony the Tanahashi Prize, which commemorates the development of outstanding technology. In February 1995, Sony was awarded the Ohkouchi Prize, recognized as the most prestigious award for production engineering and technology in Japan. These awards are proof of its high performance. In September 1995, Sony succeeded in developing lithium-ion battery module for use in electric vehicles, a project Sony began in 1992. This achievement points to the future of the lithium-ion battery, while marking a further improvement in the battery's overall performance.
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