A closer look at EV batteries (and their unexpected challenges ahead)

Electric vehicles and hybrids have gotten a lot of press lately on the green transportation scene.  Many people think electric is the way to go and they may be right.  But what is the magic behind an electric engine?  A battery, and those are made out of some pretty precious stuff.

To get a handle on batteries, here’s a look at four kinds of common car batteries.

Lead-acid

Practically the first kind of EV battery, lead-acid batteries have many years of usage behind them.  These batteries are easily available and have a relatively low cost, but they’re not made out of the most earth-friendly materials.  However, almost all people in the US recycle these kinds of batteries, so that’s a plus.  Lead-acid batteries are quite heavy and generally take up a good portion (up to 50%) of the vehicle’s mass.

Nickel metal hydride

Nickel metal hydride batteries are less efficient in charging than lead-acid, but these batteries are more energy dense than their lead counterparts.  Another benefit of these batteries?  Long life – with good care, they’ve lasted over a decade and over a hundred thousand miles.  Still, nickel metal hydride has some pitfalls, including difficult charging, shoddy performance in chilly temps, and a tendency to self-discharge.

A Nissan EV battery pack

Zebra

No, these aren’t jungle animals.  Rather, zebra is a nickname for sodium batteries that use chloroaluminate sodium as the electrolyte.  These batteries contain more energy than nickel or lead batteries with an energy density of 120Wh/kg.  Also, zebras are nontoxic and can last for a few thousand charge cycles.  Downsides?  They need to be heated to work (increased heating costs) and have poor power density.

Lithium Ion

The battery you’ve probably heard a lot about, the lithium ion battery has seen a lot of improvements lately.  New lithium ion batteries are environmentally friendly, have long life cycles (some over 7,000 charges), great power and energy density, and shorter charging cycles, which help to mitigate this big problem of EVs.

Yeah, I definitely think we want to keep this pollution, now in China, from happening in America...

All right.  So now that we’ve looked at the major types of batteries used in EVs and know what’s in them, here’s something important to know: over 90% of the world’s supply of rare earth metals are in China.  Not a huge deal, except that China is seriously considering stopping the export of these metals, essential to EV batteries and other green technologies, like wind turbines.  The motive?  Bring more manufacturing to China, in addition to building up China’s own green agenda.  So now the US and other countries are trying to find their own supplies of these rare earths, but are hesitant to begin mining, considering how hard it is to mine these metals without polluting the area around the mine.  And we all know what happens when there’s a limited supply of something: prices increase.  China’s squeeze on rare earth elements, as well as increased demand of these metals, might mean a price hike of the already-pricey EVs and hybrids.  It also might mean that we ought to make hay while the sun shines and get a jump on the green tech market while we still have the chance.