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Hitachi & Sanyo Announce HEV Battery Developments

May 27, 2009 by Jeff Shepard

Hitachi Ltd. and Hitachi Vehicle Energy Ltd. announced that they have developed a lithium-ion rechargeable battery with an enhanced power density of 4,500W/kg for use in hybrid electric vehicles (HEVs).

The new battery uses prismatic cells which measure 120 x 90 x 18mm. The cell has a current capacity of 4.8Ah, an average voltage of 3.6V and an energy density of 72Wh/kg. Hitachi will start shipping samples in fall 2009.

Hitachi is planning to mass-produce the third-generation cells in 2010 with a monthly output of 300,000 units. The third-generation product is a cylindrical cell measuring 40mm in diameter and 92mm in length. It has a current capacity of 4.4Ah, an average voltage of 3.6V and a power density of 3,000W/kg. Therefore, the power density of the fourth-generation cell is 1.5 times as high as that of the third-generation product.

The fourth-generation cell features a prismatic shape, which has a high cooling performance and makes it easy to expand the surface area of the electrodes and improve the power characteristics. Furthermore, the company optimized the particle design of the Mn-based positive electrode material. The negative electrode material is amorphous carbon as in the case of the existing products.

With the drastically enhanced power density of the fourth-generation cell, the weight and volume of batteries to be used in hybrid vehicles can be reduced by approximately 40%, according to Hitachi.

At present, the cost of the fourth-generation cell does not match that of nickel-metal hydride (NiMH) secondary batteries. But the company expects that "the cost will be lower than that of NiMH secondary batteries in the future." It aims to start volume production of the fourth-generation cells in 2013.

Sanyo Electric Co Ltd. announced the upcoming construction of a facility within its Kasai Plant (Kasai City, Hyogo), for the manufacture of hybrid electric vehicle (HEV) Lithium-ion (Li-ion) batteries. This plant is already a base for the company’s development of HEV-use battery systems.

In addition to providing HEV nickel-metal hydride batteries to Ford and Honda, the company has been carrying out joint development with Volkswagen for next-generation nickel-metal hydride battery systems, and lithium-ion battery systems. Sanyo has already installed mass-production equipment at its Tokushima Plant for the manufacture of HEV-use Li-ion batteries.

The plant is expected to begin production by the end of 2009, and initial production will start at one million cells per month.