Hitachi Automotive Systems Ltd announced in April 2016 that it has developed a high-output 48V lithium-ion (Li-ion) battery pack for mild hybrid vehicles (mild HEVs).
The company will start to ship samples to automakers in the summer of 2016, aiming to start volume production in fiscal 2018.
Currently, strong HEVs equipped with a high-voltage (100V or higher-voltage) battery are the mainstream in the Japanese market. And mild HEVs using a 12V Li-ion battery or capacitor are available only as light cars, etc.
On the other hand, in Europe, China, etc, mild HEVs using a 48V Li-ion battery are expected to be widely used because they can improve fuel efficiency with a relatively low cost. Some forecast that the production volume of mild HEVs will be more than two million units in Europe and more than four million units in China in 2023.
In view of the trend, Hitachi Automotive completed the basic design of the battery pack targeted at 48V mild HEVs in March 2016 by utilizing technologies that it developed for the production of Li-ion battery cells and battery management systems (BMSes) for HEVs.
The newly-developed 48V Li-ion battery pack is an all-in-one package incorporating battery cells, BMS circuit boards, relay and fuse. It contains 12 square batteries whose output density is about 50% higher than that of Hitachi Automotive's previous product. When a motor is used to increase acceleration, its maximum output and maximum input are 10kW or higher and 13kW or higher, respectively, (for 10 seconds).
The capacity of the battery is 5.5Ah, and the working voltage ranges from 33 to 51V. Its dimensions and mass are 175 x 280 x 100mm and 5kg, respectively. Because of its small size, it enables to design vehicle interiors more freely, the company said. Hitachi Vehicle Energy Ltd manufactures the battery pack, and Hitachi Automotive sells it.
The 48V Li-ion battery pack is scheduled to be exhibited at Automotive Engineering Exposition 2016 Yokohama, which will take place from May 25 to 27, 2016, at Pacifico Yokohama in Yokohama City.