科研之友
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摘要
Currently, fossil fuels supply over 85% of the world's evergrowing energy demand. There is an increasing concern about the global climate change resulting from the worldwide use of fossil fuels, which release large quantities of CO_2 and other greenhouse gas (GHG) to the atmosphere.1 The petroleum that is used for automobile and light truck applications represents 34% of the world's total primary energy source. In the United States, the transportation sector is the single greatest consumer of imported oil. In 2010, 94% of U.S. transportation energy was derived from petroleum, nearly half of which came from foreign sources.2 In terms of economic impact, petroleum imports represented nearly 41% of the $646 billion U.S. trade deficit in 2010.3 The CO_2 emissions due to the U.S. transportation sector account for 40% of the total CO_2 emission, which is considered as a major cause of geopolitical instability.4 The U.S. transportation sector also represents about 27% of all U.S. GHG emissions.5 However, even with today's mix of fossil, nuclear, and renewable energy sources for U.S. electric power generation, it is estimated that, on a well-towheel basis, an all-electric vehicle will generate 25% less GHG emissions than a conventional gasoline-powered vehicle.6 Even lower emissions are predicted with increased use of renewable energy sources. Therefore, it would greatly benefit the United States and the world to transition to an electrified transportation system, which is already beginning with the advent of hybrid electric vehicles (HEVs) and will accelerate as plug-in hybrid electric vehicles (PHEVs) and ultimately pure electric vehicles (PEVs) gain a larger share of the market. In addition, PEVs have the promise to greatly improve energy efficiency. For example, on a well-to-wheel basis, the all-electric Tesla Roaster charged with electricity generated from natural gas has an efficiency of 1.14 km/MJ, nearly 2 times as efficient as a Toyota Prius hybrid (0.56 km/MJ) and 4 times more efficient than a typical gasoline-powered car, such as the Toyota Camry(0.28 km/MJ).7 The use of alternative energy sources, such as nuclear, solar, and wind power, would reduce our dependence on fossil fuels and, thus, also reduce CO_2 emissions, but devices to store the electric energy generated by these power plants are sorely needed. One of the most viable candidates for such devices is the rechargeable Li battery.
- 出版日期2014-6-11
- 单位北京理工大学
