慶應義塾大学 - 電気自動車研究室
Electric Vehicles
Actual Example: Eliica - Key Elemental Technologies
Quantum mechanics, the science of examining the make-up and behavior of molecules and atoms, was first explored in the early 20th century.
The successful application of this study to molecules in the middle of the century led to the invention of transistors, which gave birth to many new technologies that changed people’s lives, including computers and mobile phones.
In 1954 Morton B. Prince, an American, invented the solar cell.
In 1982, Masato Sagawa of Japan invented the neodymium magnet. When applied to the manufacture of motors, this powerful magnet is very useful in making them more compact and efficient.
Then in 1986 Akira Yoshino invented the lithium-ion battery. It was first used to power mobile phones, before being applied to personal computers. The new century saw the development of batteries for electric vehicles and for storing large amounts of power.
The key elements of battery performance are the amount of energy that can be stored per unit mass (energy density) and the amount of power that can be instantaneously drawn from the battery per unit mass (power density). Both of these are much higher in lithium-ion batteries than in conventional batteries. Long battery life (i.e., the number of times the battery can be charged and discharged) is another advantage.
Inverters are used as controllers to alter the speed of electric vehicle motors. These require highly efficient transistors, and the 20th century has seen the invention and practical application of insulated gate bipolar transistors (IGBT).
Neodymium magnets, lithium-ion batteries, and IGBT are key elemental technologies for facilitating the widespread use of electric vehicles.
Eliica