What Will It Take to Charge Electric Vehicles Faster?怎样才能使电动汽车充电更快？

To get more EVs on the road， scientists are working to charge a car in the same time that it takes to fuel up at a gas station.

为了让更多电动汽车上路，科学家们正努力使汽车充电时间与在加油站加油花费的时间相同。

Electric vehicles are quieter， easier to repair and maintain， and far better for the environment than traditional internal combustion cars. Still， numbers of EVs on the road are trailing behind the cars they’re supposed to replace， in part due to charging times.

与传统内燃机汽车相比，电动汽车噪音更小、更易修理和维护，且对环境的危害要小得多。然而，上路电动汽车数量却落后于它们本该取代的内燃机汽车，部分原因就在于充电时间。

While refueling a gas tank only takes a few minutes， charging an EV takes a lot longer. Right now， the fastest chargers available to consumers， sometimes called Level 3 chargers， can charge a vehicle battery to 80 percent in as quickly as 20 minutes. But the most available （and affordable） chargers are far slower. Level 2 chargers take several hours to charge a vehicle， and Level 1 chargers—which plug into a typical home outlet—can take more than two days.

油箱加油只需几分钟，而电动汽车充电花的时间要长得多。目前，可供消费者使用的最快的充电桩（有时也叫三级充电桩）在20分钟内就能使汽车电池电量达到80%。然而，最常见（也最具性价比）的充电桩要慢得多。使用二级充电桩充电需要数小时，而连接家庭电源插座的一级充电桩所需时间可能超过两天。

These slow charging speeds have only exacerbated “range anxiety”—the concern that batteries could run out of charge on the road. That， and the fact that demand for EVs outpaces the ability of car manufacturers to make them， threatens to slow down the road to electrification.

缓慢的充电速度只会加剧“里程焦虑”——即对行车途中电池电量可能耗尽的担忧。这种忧虑，加上消费者对电动汽车的需求超过汽车制造商的生产能力这一事实，可能会拖慢汽车电动化的进程。

Scientists， including those at universities， at major electric vehicle manufacturers and at the Department of Energy， think that EVs could power up more quickly if we push the science of charging to its limits. They argue that tweaking the internal chemistry of EV batteries and the design of charging cables can help eliminate this major barrier to adoption. The challenge is speeding up charging without compromising on safety or the long-term life of the battery. The goal is to get as close as possible to the time it takes to refuel an internal combustion vehicle.

就职于包括大学、主要电动汽车制造厂商和能源部在内的科学家们都认为，如果将充电的科学发展到极致，电动汽车的充电速度可以更快。他们表示，稍稍改进电动汽车电池的内部化学特性和充电电缆的设计，有助于消除电动汽车推广的这一重大阻碍。难处是要在不影响安全性和电池长期寿命的前提下提高充电速度。而目标在于尽可能使电动汽车的充电时长接近内燃机汽车的加油时长。

The fundamental challenge of charging lies in batteries’ electrochemistry. Batteries are designed with two electrodes： an anode and a cathode. Lithium ions flow between these two components. When a battery is discharging and powering a car， lithium ions travel from the anode to the cathode， which produces free electrons and electric charge. When the vehicle is charging， the reverse happens， and the lithium ions are pushed back toward the anode.

最根本的难点在于电池的电化学特性。电池有两个电极：一个阳极和一个阴极。锂离子就在这两个组件之间流动。当电池放电、为汽车供电时，锂离子从阳极移动到阴极，这一过程会产生自由电子和电荷。而当汽车充电时，相反的情况发生，锂离子会被推回阳极。

The problem is that inside the battery， lithium ions face a critical speed bump. If they travel too quickly， they’ll get stuck and won’t be able to enter the anode. When lithium ions get caught， there are fewer lithium ions to provide charge， which makes the battery less effective. Worse still， if too many lithium ions build up， the battery can short-circuit and， potentially， start a battery fire.

问题是在电池内部，锂离子面临着一个关键的减速带。如果移动速度过快，它们就会卡住，从而无法进入阳极。当锂离子发生阻塞时，提供电荷的锂离子减少，会降低电池的效率。更糟糕的是，如果积聚的锂离子数量过多，电池可能会短路，并引发电池火灾。

“It turns out that moving lithium is a bit like getting 100 people into a narrow room，” says Venkat Srinivasan， director of the Argonne Collaborative Center for Energy Storage Science and deputy director of the Joint Center for Energy Storage Research in Illinois. “There’s a small door. I’d have 100 people start piling into the doorway. They’re all going to get stuck in that doorway.”

“事实证明，让锂离子移动的过程有点像把100个人塞进一个狭小的房间。”文卡特·斯里尼瓦桑说道，他是阿尔贡储能科学合作中心主任，兼伊利诺伊联合储能研究中心副主任。“只有一扇小门，我得让100个人往门口挤。他们会全堵在那里的。”

Now， some think that using new battery chemistries could make it easier for lithium ions to move within a battery cell. At Argonne， researchers are studying whether it’s possible to use multiple pathways for lithium ions to travel within a battery—and essentially reduce crowding. The challenge is designing these doorways on a microscopic level， explains Srinivasan.

目前有人认为，应用新的电池化学特性可以使锂离子在电池内部的迁移变得更容易。在阿尔贡，研究人员正在研究，是否可能采用多种路径使锂离子在电池中迁移，以从根本上减少拥堵。挑战在于在微观层面上设计这些“门口”，斯里尼瓦桑解释道。

Of course， changing battery chemistries is an extremely arduous process and requires extensive testing and validation. An easier approach to implement involves updating the software used to manage the batteries as they charge. Right now， batteries charge at a constant current， which causes charging speeds to decline as the battery refuels. Researchers at the Idaho National Laboratory believe better battery algorithms could make charging faster， by adjusting the current flowing into the battery as it’s being charged.

当然，改变电池的化学特性是一个极其艰巨的过程，需要广泛的测试和验证。一个更简单可行的方法是更新管理电池充电的软件。目前，电池主要采用恒流充电，随着电池电量增加，充电速度会逐渐下降。爱达荷国家实验室的研究人员认为，更好的电池算法可以通过调整充入电池的电流使充电速度更快。

“Maybe you keep the current low and then when the battery reaches around 30 percent state of charge， you can increase the current， because at that time the battery’s internal resistance is low，” explains Tanvir Tanim， a senior staff scientist at the Idaho National Laboratory. “When it goes closer to fully charged， then you， again， reduce rate.”