It’s commonly reported that lithium ion batteries will usher in a new era of electric cars and plug-in hybrids. Not exactly, says John German, the engineer who literally wrote the book about hybrid cars for the Society of Automotive Engineers. After 11 years at Honda, German now serves as a senior fellow for the International Council for Clean Transportation. In an interview with HybridCars.com, German said the next wave of lithium ion batteries will not significantly reduce the cost of electric cars, but they could make conventional hybrids ubiquitous.
A quick refresher course on the difference between power and energy, and why it matters.
In German’s view, the chief benefit of new lithium ion batteries is their greatly enhanced power capabilities—the rate at which energy can go in and out of the battery. “But they don’t store any more energy than the current lithium ion batteries do,” said German, “What we are looking at is a battery which is perfect for conventional hybrids.”
HybridCars.com: Why will the new breed of lithium ion batteries be a bigger benefit to conventional hybrids rather than plug-in hybrids and electric cars?
German: The next generation of lithium ion batteries will reduce the cost of the battery pack for conventional hybrids, but they’re not going to reduce the cost of the battery pack for plug-in hybrids and electric vehicles. In effect, these batteries will increase the cost differential between conventional hybrids and plug-in hybrids. That’s going to make it harder for plug-in hybrids to compete with conventional hybrids.
Walk me through the energy and power requirements for the two different categories of vehicles.
For plug-in hybrids and electric vehicles, it’s all about the range. You need a certain amount of energy to drive a certain distance [before needing to recharge]. That’s independent of the battery chemistry. If the new lithium ion chemistry doesn’t store any more energy than your old lithium ion chemistry, then you need just as much battery to drive that distance.
And with conventional hybrids, you don’t need nearly as much energy.
The battery packs in all existing hybrids, up until the new BMW ActiveHybrid 7, are oversized. The reason they’re oversized is that with nickel metal hydride [the technology used in today’s hybrids], you’re limited in how fast you can take energy in and out of a battery without causing significant deterioration. So these batteries are not sized for the energy [storage] requirements. They are sized for the power requirements, so they can deliver enough power without significant deterioration. As a consequence, they hold a lot more energy than they really need to.
With the new high-power lithium ion batteries, they can cut them down to their actual energy requirements and still get all the power they need.
So, with the new lithium ion batteries, the difference in cost between conventional hybrids and gas-powered vehicles could come in line?
In another 10 to 15 years, we should be at the point where the mainstream customer, the average customer, will accept the cost of a hybrid system.
Meaning, maybe a couple of hundred dollars more than a conventional car?
Well, $1,000 to $1,500 more. There’s enough benefit for mainstream customers to accept it.
How rapid will the transition from nickel metal hydride to lithium ion batteries be for conventional hybrids?
It’s a function of sales volume. The current generation of lithium ion batteries is not any cheaper than nickel metal hydride. And they’re not proven. With a lot of the lithium ion chemistries, just sitting and doing nothing in hot weather will degrade the battery pack. The batteries will not last as long in Phoenix as Minneapolis. There’s risk with durability and reliability.
In lower volume applications, new hybrids just coming out, carmakers know they’re not going to be able to capture larger market share right away. So they’re going to be lithium ion batteries starting tomorrow [See Mercedes S400 Hybrid and BMW ActiveHybrid 7]. You don’t have a large volume, so your risk is minimized and you’ve gained experience. It’s going to be cheaper in the long run, and you want to gain experience. So, you’ll see very few new hybrids using nickel metal hydride.
The problem is with high volume existing hybrids. When you’re selling hundreds of thousands of Priuses globally every year, if you encounter something wrong with the lithium ion battery pack, your exposure is enormous. The high volume hybrid applications are going to go to lithium ion last. But even the high volume ones will get there by 2015 or so.
What’s your feeling about the cost per kilowatt-hour of lithium ion batteries? What are they now and where do they need to be?
I thought they were $1,000 per kilowatt-hour, but I’m hearing that it may be more like $700. It’s hard to determine the long-term price potential. They shouldn’t have much trouble getting down to about $320 per kilowatt-hour. It’s going to take a while, but with higher volumes and better production methods, $320 is achievable in the 2018 to 2020 time frame.
The real question is how low can you drive it. I’ve seen some people suggest that the lowest could be $250 to maybe $175.
At $250, doesn’t mean that plug-in cars become affordable?
No. At $250 per kilowatt-hour, the pay back is roughly similar to the hybrid vehicles of about five years ago. So there’s your market, about 3 percent.
If lithium ion batteries bring the plug-in market to 2 or 3 percent, where will conventional hybrids go?
I’ll stick my neck out and say that by sometime around 2025 or 2030, conventional hybrids will be over 70 percent of the market.
And a fairly steady ramp up from now until then?
Yes. It will be a curve. Something like a doubling of hybrid sales every three to five years. There’s no doubt in my mind that by 2030 that hybrids will be in more than half the vehicles sold in the US. I would be astounded if they weren’t. By 2020, I would say we’d be somewhere in the 10 – 15 percent range.
And President Obama’s goal for 1 million plug-in hybrids by 2015?
It’s not likely.