2011-07-29 | Editor:Ted 6510 pageviews

Industry Development Progess of Lithium Battery for EVs

Recent news unveiled that Mitsubishi Motors is looking to produce 8 types of electric vehicles and plug-in hybrid vehicles. Mitsubishi’s Corporate General Manager, Yoshikazu Nakamura, indicated that in order to secure stable and sufficient supply of power batteries, the company is now aggressively seeking new global suppliers of lithium batteries.

Nakamura indicated that the company is scheduled to introduce i-series electric vehicles in the U.S. market in November and is taking Toshiba as well as some Korean lithium manufacturers into consideration.

Mitsubishi is also going to introduce smaller commercial vehicles and a new i-series EV that is low-cost but travels in short distance in the Japanese market. Traditional i-series EVs adopt batteries made by Lithium Energy Japan, a joint venture of Mitsubishi and GS Yuasa.

Toshiba’s power battery for EVs is reliable in terms of performance, but the shortcoming is its shorter travel distance. Lithium battery can increase the travel distance of an EV, but undersupply of lithium battery for EVs is the potential concern.

Mitsubishi is seeking other supply sources including some Korean companies. Nakamura, though unwilling to tell the detail, said LG Chem and Samsung SDi are the two largest suppliers. He further indicated that Korean battery is very cost competitive but their supply is limited. Mitsubishi hopes that the production of EVs and hybrid EVs will reach 5% of the company’s total capacity by 2015 and 20% by 2020.

EnergyTrend predicts global production capacity of xEVs which include hybrid, plug-in and pure electric vehicles to reach 3.5 million units by 2015.

Extended Capacity for Better Durability

Sumitomo Electric Industries recently announced that the company has successfully developed a porous aluminum material that will extend the battery’s energy capacity by 1.5 to 3 times. Currently, the positive electrode and negative electrode current collectors of Lithium-ion batteries are often respectively made from aluminum foil and copper foil. The company replaces the commonly used aluminum foil with the new material, called Aluminum-Celmet, to enhance the capacity. Celmet is a porous metal made from nickel and can be easily processed through cutting and pressing. Its quality makes it suitable for coupling with active materials to collect and maintain electric current and thus is currently used as the positive electrode current collector of batteries for electric vehicles.

The extended capacity from using aluminum-celmet will enable electric vehicles to travel farther and last longer before the battery dries. If the capacity is to stay unchanged, the volume, or the weight, of the battery will be reduced by 1/3 to 2/3.

The product is being manufactured in small quantities in the company’s Osaka production site and will be mass produced and commercialized in the lithium battery and capacitor areas.

Lighter Weight Means Longer Travel

24M Technologies is a spinoff venture of A123 Systems that focuses on the production of energy storage system, to develop more advanced batteries at a lower price for electric vehicles. 24M Technologies, with the collaboration with MIT and A123 Systems, combines the best rechargeable battery technologies to improve the energy storage systems. Specifically, the company wants to create batteries to target the transportation and electric grid industries.

One hurdle being that lithium batteries used for electric vehicles or plug-in hybrid vehicles contain only about a quarter of components that directly contribute to the energy storage efficiency while the rest are inactive components that account for a considerable amount of cost and weight such as conductive foil, glue, and packaging.

24M Technologies intend to create a new type of battery by greatly reducing the inactive materials. In comparison to batteries currently used for EVs, the new battery may reach the cost as low as $250 KWH, cheaper than half of current cost.

Traditional flow battery is practically too large to be used in automotive applications because of the diluted energy storage solutions. The new design by the company will reduce the amount of inactive materials while increasing the energy storage capacity. The amount of inactive materials normally increases as the capacity increases because increased capacity has to come from increased electrolyte materials that in turn require more use of current collectors, metal foil and plastic thin film. To overcome this issue, the key is to use the electrodes that are not solid films stacked in a cell, but sludge-like materials separately stored in a tank for positive electrolyte and another for negative electrolyte.

One particular challenge incurred during the development process is to extracting electric charge out of the sludge. Compared to an ordinary lithium battery, the electrons do not flow through the electrolyte like they usually do through solid conductive particles. So the company mixed nano carbon particles into the sludge that will provide interconnected networks as pathways for electrons to travel. Though the problem remains before the new design can be introduced to the market as the electrical conductivity is still 100 times less than that of a practical system, the research team is looking for a way to increase the density of active materials in the sludge.

Acceleration without Compromising Capacity

An innovative company, Wuhe, set out to produce new electrolyte material and battery that can further reduce the cost of an electric vehicle. The company uses the latest nanotechnology to assist in developing a new material that will allow spontaneous transmission of large amounts of electricity which is needed for acceleration without increasing the capacity.

The cost of batteries is an obstacle to the development of electric vehicles, either making the retail price unaffordable to the general public or forcing manufacturers to adopt smaller battery that limits the travel distance. Although the cost of using nano particles from iron-phosphate is about 10% higher, it attains higher conductivity that will increase the capacity twofold.

Wuhe was founded in 2010 and has the production capacity of 300 tons of electrolyte materials, sufficiently able to supply for 500 electric vehicles.

Image Source: EnergyTrend

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