When a glucose solution is poured into the white cubes, the Walkman begins to play. When an isotonic drink is poured in, a propeller starts to spin. In the summer of 2007, the Sony-developed bio battery was announced in newspapers, magazines, and TV reports, and evoked a strong response. Carbohydrates (glucose) are broken down to release energy and generate electricity. This bio battery, which is based on mechanisms used in living organism, is not only friendly to the environment but also has great potential for use as an energy source.
This prototype bio battery has achieved the world’s highest power output of 50 mW*2 when employed for a passive type*1 system. These research results were published at the 234th American Chemical Society National Meeting & Exposition in August 2007 and earned respect from an academic point of view.
Sony successfully demonstrated bio battery powered music playback with a memory type Walkman and passive speakers (which operate on power supplied by the Walkman) by connecting four bio battery units in series. The case of this bio battery, which is made from an organic plastic (polylactate), is designed to be reminiscent of a living cell.
Plants create both carbohydrates and oxygen by photosynthesis from carbon dioxide and water. Animals take up those carbohydrates and oxygen and utilize them as an energy source and release carbon dioxide and water. Then this cycle starts again. Since the carbon dioxide is recycled in this system, the amount of carbon dioxide in the atmosphere does not increase. If electrical energy could be directly acquired from this cycle, we could obtain more environmentally friendly energy than that from fossil fuels. Furthermore, renewable energy sources such as glucose (which is present in plants and therefore abundantly available) have an extremely high energy density. One bowl of rice (about 100 grams) is equivalent to 160 kilocalories, which corresponds to the energy about 64 AA alkaline dry cells. Therefore, this bio battery, which is based on Energy for activity, that is the ATP and thermal energy commonly used in the living organism, can be obtained from the exchange of the electrons and protons through these two enzymatic reactions. To take advantage of this living organism mechanism, the energy for activity from inside the organism must be removed outside the organism as electrical energy.
That is, when the electrons and protons move from enzyme to enzyme, it is necessary to extract just the electrons and divert them through a separate path. Thus Sony used an electron transport mediator so that electrons could be exchanged smoothly between the enzymes and the electrodes that are the entrance and exit to that detour. The principles of the bio battery are based on the energy conversion mechanism in living organisms. However, in order to create the bio battery, several technologies needed to be developed. These include immobilization of enzymes that are normally incompatible with carbon and metal electrodes, electrode structures, and electrolytes. mechanisms used in living organisms, is not only friendly to the environment but is also likely to be of practical use as an energy source. Sony has focused on these advantages since 2001 and has developed an electrical power generation device that uses mechanisms similar to those in living organisms.