Hitachi Develops 48V Lithium-Ion Battery Pack for Mid-Range Hybrid Electric Vehicles

[Global Network Technology Report] It is reported that Hitachi Automotive Systems Co., Ltd. has developed a 48V lithium-ion battery pack with a high output density and energy density for medium-range hybrid vehicles. The output density reaches 1.25 times*1 of the traditional single product, and the energy density reaches 1.5 times*1 of the traditional single product. In the future, Hitachi Automotive Systems will start supplying samples to automaker customers and commit to mass production in 2019.

In recent years, a medium-sized hybrid electric vehicle system driven by a battery and a motor assisted gasoline engine has received extensive attention as a technique for effectively reducing the fuel consumption of a passenger vehicle. In 2016, the annual output of medium-sized hybrid vehicles reached about 450,000 vehicles, and it is expected to exceed 12.8 million vehicles*2 by 2023. Especially in Europe and China, the moderate oil-electric hybrid system equipped with a 48-volt lithium-ion battery has good fuel economy and high cost performance.

Hitachi Automotive Systems has been keeping abreast of the market development trend. In March 2016, a 48V lithium-ion battery pack for mid-range hybrid vehicles was developed, combining lithium-ion battery packs for hybrid vehicles that used to have advantages. Body manufacturing technology and battery management system (BMS) technology.

Lithium-ion batteries achieve charge and discharge by moving lithium ions in the electrode material. In order to increase the battery output density, the conventional method has generally been to reduce the thickness of the electrode film to reduce the resistance. However, after the increase in output density, there has been a problem of insufficient energy accumulation capacity. The new lithium-ion battery pack has been micrometer-scaled to improve the electrode structure of the battery, resulting in an easy-to-flow structure of lithium ions. Without reducing the thickness of the electrode film, the resistance is reduced and the output density is increased. At the same time, the material composition of the positive electrode and the negative electrode is further improved, the lithium content accumulated per unit weight is increased, and the energy density is increased. As a result, the new lithium-ion battery pack has a new high output density and energy density. The output density is equivalent to the traditional single product *11.25 times, and the energy density equivalent to the traditional single product*11.5 times.

In addition, the new lithium-ion battery pack also realizes the control of the internal resistance of the battery cell, reduces the heat generation, and uses the metal with high thermal conductivity and high heat-dissipation to make the frame of the lithium-ion battery pack, thus eliminating the need for The cooling fan improves the freedom of installation, effectively reduces the overall thickness of the product, and at the same time enhances the quiet performance.

With the increase of output density, the torque performance when the motor accelerates and assists is strengthened, the maximum output power can reach 12kW or more, and the starting strength is more powerful. At the same time, the maximum input power has reached more than 15kW, and the large amount of renewable energy generated at the moment of sudden braking can also be recycled, reducing energy consumption. Based on the improvement of input and output performance, fuel consumption has also been effectively reduced with increasing energy density.

This product was developed and sold by Hitachi Automotive Systems and was manufactured by Hitachi Vehicle Energy Co., Ltd., President of the company, which manufactures lithium ion batteries for vehicles.

This product has been unveiled at the "Technology Exhibition of Auto Technicians and Vehicles 2017 Yokohama" held in Yokohama, Japan from May 24th to May 26th.

In the future, Hitachi Automotive Systems will continue to provide electric power transmission products that include high-performance, high-reliability lithium-ion batteries for electric vehicles with huge potential market demand, promote the development and popularization of electric vehicles, and contribute to environmental protection. .

*1 Comparison with 48V lithium-ion battery pack for medium-sized hybrid vehicles developed in March 2016

*2 Source: HIS Automotive (May 2017)

■ Newly-developed 48V lithium-ion battery pack for medium-hybrid hybrid cars

■ Specifications for newly developed 48V lithium-ion battery packs for medium-hybrid hybrid cars