Driven by tighter regulations of carbon dioxide emissions and environmental protection regulations, Electrical vehicle is becoming a worldwide focus.
According to industry research institute Energytrend, the power source of automobile is gradually switching from traditional engine to electrical battery module. Therefore, the key for development of electrical vehicle lies in the auto-use batteries. The following factors should be considered when evaluating such batteries: power density, energy density, lifespan and cost.
The batteries currently applied in hybrid electric vehicle(HEV) and electric vehicle(EV) include Lead-acid battery, NiMH battery, Lithium ion battery, fuel cell and solar cell. The performance, cost and safety of auto-use batteries determine the evolvement of hybrids and pure electric vehicles.
According to EnergyTrend, the auto-use batteries generally feature large capacity and high power output. There are a couple of factors to be observed when evaluating these batteries. Firstly, Power Density (W/kg), which represents the amount of power supplied by a unit (1kg) of battery, determines the maximum output power of the battery and the automobile’s accelerating ability and maximum speed, thus directly influencing the dynamism of the car.
The Energy Density (Wh/kg) generally represents the energy restored in a unit of battery. Energy Density can be calculated by dividing the total energy released by the chemical reaction inside the battery by the gross weight or volume of the battery. And the Energy Density also represents the cruising ability of the car under pure electric-driven pattern.
Besides, the operation of auto-use battery is a recycling process of recharge and discharge. Every time the battery recharges or discharges, the chemicals in the battery are undergoing an inreversible chemical reaction. As the times of discharge and recharge increase, the chemically reactive substances in the battery get aging, reducing the recharge and discharge efficiency of the battery. Therefore, Cycle Life is an important index to measure the lifespan of an auto-use battery, and is of direct influence on the use of the battery.
The cost of battery is related to its new technology content, material, manufacturing process and production volume. Currently, the newly-developed auto-use batteries are still high in cost. If the challenge of cost could be conquered in the future, the popularization of electric cars will be accelerated.
