They may be facing extinction in the electric-transport revolution, but one benefit of cars with internal combustion engines is that they are easy and quick to refuel, so travelling a long way in one is rarely a problem. Not so for their successors. In the absence of universal standards, electric cars come with a variety of charging systems and different sorts of cables and sockets. Extended journeys therefore need careful planning to make sure that the battery is fully charged at the start and that compatible fast-charging stations are available en route.

在电力交通工具革命中,内燃机驱动型汽车可能正面临被淘汰的命运,但它的一个优点是补充燃料方便快捷,所以驾驶一辆汽车长途旅行没什么问题。但后继汽车不是这样,在缺少通用标准的情况下,电动汽车使用各种充电系统,电缆和插座也各不相同。因此,长途旅行需要周密的计划,出发前确保电池满电,途中有兼容的快速充电桩可用。

It would be much more convenient if electric cars could be recharged wirelessly. Some electric toothbrushes and other small devices, such as mobile phones, can already be topped up in this way using a process called electromagnetic induction. This employs an alternating mains current flowing through a coil to create a varying magnetic field, which then generates another current in a second coil placed alongside it according to principles elucidated in the 19th century by Michael Faraday. The device containing the second coil then converts the transmitted power into direct current, which is used to recharge a battery.

如果电动汽车可以无线充电就方便多了。有些电动牙刷和手机等小型设备已利用电磁感应原理实现了无线充电。根据19世纪迈克·法拉第阐明的原理,让交流电流经一个线圈产生交变磁场,邻近的次级线圈可产生另一股电流,包含次级线圈的设备再将传输的电能转化为直流电,从而为电池充电。

As users of electric toothbrushes and phones will know, device and charger must be both close to each other and precisely aligned for this process to work. That is tricky to achieve with an electric car, which sits above the ground and requires higher levels of energy transfer.

电动牙刷和手机用户都知道,设备和充电器必须相互靠近和对齐,该充电原理才能奏效。这对电动汽车来说很难实现,因为它位于地面,需要传输的电能较大。


WiTricity is working with a number of carmakers and sold its first commercial system in 2018 to bmw, which fits it to some of its 530e hybrid cars. Alex Gruzen, WiTricity’s boss, expects further developments soon. He says the arrangement can transmit power from the grid to the car’s battery with an efficiency of up to 93%, which is similar to that achieved by a plug-in system. Nor does a car’s receiving coil have to be positioned directly above the charging pad on the ground—a useful feature of resonating coils being that they do not have to be so closely aligned to transmit power.

WiTricity正在与多家汽车制造商合作,2018年将首款商用系统出售给了宝马公司,后者在部分530e混合动力车上使用了该装置。WiTricity公司总裁亚历克斯·格鲁泽期待不久将有更大的进展。他表示该装置能使电网向汽车电池输送电能的效率达到93%,接近插电式充电装置的效率。汽车的接收线圈不必放置在地面充电垫的正上方,这种线圈共振特性很有用,因为两者不必对齐就能传输电能。



Other companies are producing wireless-recharging systems which use various forms of magnetic-resonance induction. So far these are mostly for commercial vehicles, though such systems are bound to encourage the spread of the technology to cars as well. Momentum Dynamics, a Pennsylvanian firm, for instance, announced in March a deal to supply wireless rechargers to GreenPower Motor Company, a producer of electric shuttle buses.

其他企业正在生产无线充电装置,它们采用各种磁共振感应方式。目前大部分被用于商用车辆,但这种装置必将推动该技术在乘用车上的普及。例如:美国宾夕法尼亚州一家名为Momentum Dynamics的公司在3月份公布一笔交易,向电动区间车制造商GreenPower Motor Company供应无线充电装置。


Crucially, as did not happen for plug-in vehicles, standards are being developed that should, at least in theory, permit any suitably equipped electric vehicle to use any wireless charger. China recently ratified a set of national criteria similar to those being developed and promoted by industry groups in the West, including WiTricity. As China has been one of the countries most forcefully pushing the electrification of vehicles, its clout in the marketplace might ensure that most companies, foreign ones included, keep to the standards it has set.

至关重要的是,该行业正在研究相关标准,至少从理论上允许一切配置得当的电动汽车使用所有的无线充电装置,这是插电式电动汽车所不具备的。中国最近通过了一系列国家标准,类似于西方行业团体研究和推广的标准,包括WiTricity公司。由于中国是最大力度推动汽车电气化的国家之一,其市场影响力可能会确保包括外企在内的多数企业遵守中国制定的标准。