How Long Do Electric Car Batteries Last?

它们与燃气发动机相比又如何呢?

The battery of an electric car on display during Electric Mobility Week.
The battery is the most important and most expensive part of an electric vehicle. Adam Berry/Getty Images.

The battery is by far the most expensive component in an electric vehicle, so estimating how long it will last is an important consideration if you're thinking of switching to an EV. One way to look at it, however, is by asking: How long will an EV battery lastbefore I have to pay to replace it?The short answer: With few exceptions, your EV battery is guaranteed to work significantly longer than an engine in a gas-powered car is, and in most cases, your battery will outlast the rest of your car's lifetime.

The longer answer comes in examining what's under warranty. For electric vehicles, the federal government mandates that manufacturers warranty a battery for a minimum of eight years/100,000 miles. In California, that mandate is 10 years/150,000 miles.一些车辆甚至提供无限英里覆盖他们的电池。相比之下,大多数燃气动力车辆(包括发动机、变速器和分动箱)的动力总成保修期为5年/60000英里。The最低限度电动汽车电池的保修期比动力总成的平均保修期长3年/40000英里。这是今天普通汽车在路上使用寿命的四分之一。

Understanding the Battery

锂离子电池示意图
How energy flows in and out of a lithium-ion battery. VectorMine/Getty Images.

The main battery type in electric vehicles is the lithium-ion battery. Lithium-ion batteries revolutionized portable technology because they are lightweight and “energy dense,” meaning they can carry much more energy per mass than other battery types. This has made them light enough to make electrified transport possible. With increasing economies of scale, lithium-ion battery prices have dropped by 97% since 1991 and continue to keep falling.Since the battery is by far the most expensive component in an electric vehicle, experts predict that the sticker price of an EV will be cost-competitive with comparable gas-powered cars in the next two to three years.

An EV battery is a pack of individual battery cells, each about the size of a AA battery. They are bound together physically and electronically with circuitry and software to regulate the charging and discharging of energy. A battery pack might have 96 individual cells, grouped in eight modules of 12 cells each.

Lithium is the third lightest element on the periodic table, after hydrogen and helium. It has three electrons orbiting three protons with two electrons on its inner shell and one on its outer shell. That one outer electron, bound to the nucleus by electromagnetic force, can be knocked loose by a larger electromagnetic force, which creates a lithium ion with a positive charge (since electrons are negatively charged). The flow of those ions is what creates an electric charge.

What Is an Ion?

离子是带电原子。所有的非放射性elements on the periodic table have the same number of negatively charged electrons and positively charged protons. But when an element loses or gains an electron, it's called an ion. Being unstable, ions move around to gain or shed an electron.

锂离子电池将锂离子储存在电池的独立部分,称为阳极和阴极。一种叫做电解液的溶液将带正电荷的离子从阳极带到阴极,产生的电荷从电池的正极端流出,进入笔记本电脑、电话或本例中车辆电机的电路,然后回到电池的负极部分。当车辆接通电源时,电子流从阴极流向阳极,为蓄电池充电。

影响电动汽车电池寿命的因素

锂离子电池确实有其局限性;随着时间的推移,它们能够储存的能量会减少。然而,对电池性能下降的担忧更多的是车辆的续航里程问题,而不是其可用性问题——当然,这是一个合理的担忧,但并不一定需要更换电池。以每年2.3%的平均退化率计算,“绝大多数电池将超过车辆的使用寿命。”

A Problem of Estimates

The problem with estimating what the actual lifetime of an EV battery is, rather than its warrantied lifetime, is that the data available is limited by the amount of time in which EVs have been on the road. Of the 1.4 million electric cars sold in the United States since they were introduced in 2010, only 400,000 are older than five years.日产聆风于2010年底引入美国,雪佛兰博尔特于2016年底进入美国市场,而特斯拉的畅销车型3于2017年年中推出,首款达到10万英里的车型3车主在2019年才推出。Battery efficiency and energy density also continue to improve on a regular basis. When the U.S. Department of Energy's National Renewable Energy Laboratory estimated in 2014 that EV batteries may last 12 to 15 years in moderate climates (eight to 12 years in extreme climates), it aptly noted that “long-term validation [is] still needed.”

What the actual lifetime of the engine in a gas-powered car is no easier to estimate, however. The average lifetime mileage of a gas-powered passenger car is 133,017 miles,but cars come off the road for many reasons other than engine failure. If you asked an expert for an estimate of how long a gasoline engine lasts, you will probably get a vague answer: it all depends on how well the engine is made and maintained. A common estimate is 150,000 miles.

Battery Replacement Costs

While lithium-ion battery prices have dropped by 97% since 1991, and they continue to keep falling, replacing an EV battery is still more expensive than replacing a gas car's engine. Excluding labor, a new engine might cost from $4,000 to $7,000, depending on how many cylinders it has, while a used engine is a tenth of that price.更换日产聆风的24千瓦时电池,新电池的成本从5500美元到翻新电池(不包括人工)的一半不等。更换一个特斯拉3型电池可能需要13500美元。Since EV batteries are constructed out of many separate modules, however, and those modules are composed of individual cells, it may not be necessary to replace the entire battery pack. The experts atCurrent Automotivenote that they have encountered only one case where an entire Tesla battery needed replacing.

How to Maximize Your Battery Life

The main thing that influences battery lifespan is the number of cycles each battery cell goes through. (A battery cycle is the discharge and recharge of the battery.) The following advice comes fromMotorTrend,Car and Driver,以及电动汽车充电站制造商ClipperCreek。

  • 就像驾驶汽油动力汽车一样,你的驾驶方式会影响你消耗的能量。同样的道理也适用于电动汽车:快速启动和剧烈的加速会将电瓶的能量吸引到电机上。
  • Avoid fully charging your battery if you don't need a full charge. Avoid fully discharging the battery as well. Unless an upcoming road trip or commute requires a full charge, keep your battery charged between 30 and 80%, where the battery is at its most efficient.
  • Avoid temperature and humidity extremes. High temperature cause the battery cooling system to work harder (and use more energy), while low temperatures should be avoided while charging. Temperatures between 60 and 80 degrees F are when EV batteries are at their most efficient.
  • 快速充电很方便,但会降低电池的长期容量。
  • Plan your route ahead of time. If you need to charge while on the road, a good plan can help you avoid having to resort to fast-charging. Should you not have enough charge to get you to your destination, only charge enough to get you there, then complete your charging upon arrival.

为持久而生?

如果电动汽车制造商要吸引客户,他们就需要向他们保证,他们的汽车是耐用的,包括电池。虽然电动汽车最近在市场上的出现使得人们很难知道它们的未来,但汽车行业的专家预测,电动汽车上的电池可能会比汽车的其他部分寿命更长。

View Article Sources
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  10. 如上所述,汽油车在路上行驶的平均时间约为11.6年,美国乘用车的平均行驶里程为11467英里(美国能源部能量Efficiency & Renewable Energy, Average Annual Vehicle Miles Traveled by Major Vehicle Category," March 26, 2020). 11.6 X 11,467 gives us an average of 133,017 total miles driven per vehicle.

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  14. 同上。

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  17. Mueller, Jason. “延长电动汽车电池寿命的10个小贴士.”ClipperCreek, March 1, 2018.