Maybe we have the battery revolution all wrong

June 8, 2011 - via

Several years ago, when Toyota announced that lithium would power the third generation Prius, I believed that hybrid cars were about to become commonplace and that the push towards plug-ins would quickly and steadily advance. By 2020 I was convinced every new car would be a hybrid or plug-in.

Then Toyota put its lithium plans on hold.
Likewise, as lithium has advanced towards automotive reality, study after study has suggested that the lithium revolution isn’t nearly as ripe as I had once hoped. And some new research suggests that maybe we just have the battery all wrong – and maybe the revolution.

Recently, at the 4th Symposium on Energy Storage: Beyond Lithium-ion, Jürgen Leohold, head of Volkswagen Group research, suggested that while electrification makes perfect sense, lithium-ion batteries continue to be a drag on success.

According to Leohold today’s commercially available lithium-ion batteries have an approximate energy capacity of 120 Wh/kg, and by 2020 energy capacity will probably jump to 200 Wh/kg. However, 400-600 Wh/kg is needed to really get the plug-in revolution going, and 1,000 Wh/kg will probably be required to fully compete with advanced ICE vehicles – at least according to Leohold.

Unfortunately, achieving 400+ Wh/kg, Leohold suggests, will require a technology beyond lithium-ion, a sentiment expressed by many lithium-ion researchers and studies. That could take decades based on the time it took to develop today’s lithium-ion technologies.

In the comments regarding Leohold’s assertions posted on GreenCarCongress, however, some have taken exception, claiming that Tesla is already proving Leohold wrong with next gen battery packs intended for vehicles like the Model S that have pushed well beyond 120 Wh/kg.

But again, are Tesla’s batteries commercially available? No. Even if they become available for 15,000 Model S’s per year in the next few years, does that mean they will be commercially available for mass production throughout the auto industry? Probably not.

Inevitably, until there are feasible real world production capabilities for enough battery packs to produce several million vehicles per year, minimally, such battery packs really aren’t commercially available based upon any meaningful auto industry scale.

Still, maybe Tesla will achieve some unexpected lithium-ion breakthrough, or Argonne, or Toyota or any number of others deep in lithium R&D.

Or, maybe the battery needs to be entirely re-imagined.
Researchers at MIT, for instance, have been working on semi-solid flow batteries since 2010 that separate energy storage and discharge into two separate structures. According to AutoWeek, if perfected, battery size and cost could therefore be cut in half.

Of course, like other battery technologies, many engineering obstacles still exist and perfecting semi-solid flow batteries for auto use could still take many years.

In many ways, chaos might be the perfect way to describe the state of the battery industry, especially those for plug-in vehicles. Almost anything is still possible.

So, what does that say about the battery revolution?
The plug-in revolution is going to take longer than most advocates are willing to accept. There is still too much uncertainty, and costs are still too high. Even when these issues are resolved, it will take decades to replace the hundreds of millions of cars already on US roads.

Nevertheless, lithium can still make sense beyond just plug-in vehicles. Even lithium-powered mild hybrid technologies offer huge potential to reduce foreign oil consumption and CO2 emissions, today. In the next decade, while lithium-powered plug-ins attract all the hype, mild lithium hybrids could achieve far greater results.

At the end of the day, the world is not yet on the verge of a battery-powered plug-in revolution, but we still have enough tools to be revolutionary as fully electrified vehicles are perfected – something that could years, or even decades. The real question seems to be, will we have the courage and vision to take advantage of the low hanging fruit now, or will we rot in the status quo as we wait for perfect solutions?

External link:

Author:Hybrid Car Blog