EV Makers Facing Development Bottlenecks (1)

published: 2011-04-14 11:24 | editor: | category: Knowledge

As EV makers gradually increased investment in R&D in recent years and some technology bottle necks have been overcome. Yet, there is still a number of impracticalities that industry experts believe are holding back the future development of EVs.

Power batteries are the heart of EVs, and require high standards including high power capacity, high energy density, ability to fast charge and discharge and consistent depth of discharge, not to mention a long lifespan with an affordable price. Currently, lead-acid battery is mature in technology advancement and has lowest manufacturing costs but is not suitable for automotive power usage due to its technology constraints. Ni-Mh battery is better than lead-acid battery in terms of the performance, however, its ability to fast charge and discharge, power capacity and energy density still need much improvement and advancement.

Lithium is now widely considered as a solution for such shortcomings. A number of advantages that lithium batteries possess are high operating voltage (3 times more than Ni-Mh battery), high energy density (3 times more than Ni-Mh battery), small in size, light in weight, longer lifespan, no memory effect, zero pollution, and low self-discharge rate.

Among various types of lithium batteries, lithium-iron batteries are what is mostly adopted for safety and price reasons, even though its energy density is less than that of lithium-cobalt batteries. Nevertheless, its lower price does not make up for market affordability. Hypothetically, if an EV weighs 1.5 ton with highest speed of 130 km/h, the required amount of lithium battery would be 350 kg (76AH, 320 operating voltage).

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