Information contained in this news release is current as of the date of the press announcement, but may be subject to change without prior notice.
November 14, 2014
Energy density of 335 Wh/kg achieved
with high-capacity anode and cathode materials
Tokyo, November 14, 2014 - Hitachi, Ltd. (TSE: 6501) announced the development of a battery technology that doubles the driving distance of electric vehicles *1.
Specifically, the electrode is twice the thickness of conventional batteries, thus increasing the amount of lithium-ion's available for charging and discharging and increasing the energy density. Another feature is optimization of the distribution of the active material within the electrodes to promote lithium-ion mobility and increase battery power density. That was achieved by using a newly developed technique for three-dimensional visualization of electrode structure to clarify lithium-ion movement.
Silicon-based anode materials are capable of charging and discharging more lithium ions than conventional carbon-based materials, but they have a short service life because they are easily separated from the electrode. We have developed a technique for strongly binding silicon materials to the electrode to suppress that separation, thus achieving the service life that is about the same as carbon-based materials. Another problem with conventional anode materials is that application of a high voltage causes decomposition of the electrolyte, shortening the service life. We were able to overcome that problem and extend lifetime by coating the cathode surface with oxide. By applying these solutions, we were able to achieve high energy density and power density together with a long service lifetime, resulting in batteries that can double the driving range of electric vehicles.
Electric vehicles hold promise as environment-friendly vehicles that do not emit carbon dioxide. On the other hand, widespread use of such vehicles requires that the driving range be extended by using lithium-ion batteries that have both high energy density and power density and a long service life. Hitachi has solved those problems by developing technology that achieves an energy density of 335 Wh/kg (higher than previous performance by a factor of 2.6 *2) and a power density of 1600 W/kg for the 30 amp/hr-class cell that is actually used for electric vehicles. That achievement makes it possible for electric vehicles to drive twice as far on one charge. The features of the technology we developed are described below.
Hitachi will continue with R&D to achieve practical lithium-ion batteries that apply the elemental technology we have developed by 2020.
The work reported here was done as a part of the Applied and Practical Lithium Ion Battery Development for Automobile and Multiple Application Project of the New Energy and Industrial Technology Development Organization. The results of this research will be presented at the 55th Battery Symposium, which is to begin on November 19, 2014 in Kyoto, Japan, and is organized by the Committee of Battery Technology and the Electrochemical Society of Japan.
Hitachi, Ltd. (TSE: 6501), headquartered in Tokyo, Japan, delivers innovations that answer society's challenges with our talented team and proven experience in global markets. The company's consolidated revenues for fiscal 2013 (ended March 31, 2014) totaled 9,616 billion yen ($93.4 billion). Hitachi is focusing more than ever on the Social Innovation Business, which includes infrastructure systems, information & telecommunication systems, power systems, construction machinery, high functional materials & components, automotive systems, healthcare and others. For more information on Hitachi, please visit the company's website at http://www.hitachi.com.