Improved Electrolyte Claimed to Facilitate Vastly Improved Batteries

May 31st, 2012 by Nicholas Brown

Researchers have been experimenting with lithium-ion concepts that could improve the energy density of lithium-ion batteries significantly, but they all have their drawbacks and limitations. Researchers at Boulder Ionics say that it is the electrolyte that lithium-ion batteries use which is limiting their ability to be economical.

Boulder Ionics’ CEO/co-founder Jerry Martin says that the company is developing a new electrolyte that gives batteries higher performance capabilities. The electrolyte is made from ionic liquids, which are salts that are molten below 100 ⁰C (212 ⁰F).

One quality of this type of electrolyte is that it is able to operate at relatively high voltages and temperatures, and this means that fewer batteries than usual can be used to achieve the voltage required by whatever the battery is being used to power.

For example, it is common for a lithium-ion cell (a cell is a single lithium-ion battery, not a battery pack) to be 3.7 volts, and to achieve 300 volts, 81 of these little cells would have to be connected to each other using what is called a series connection. 81 cells x 3.7 volts = 300 volts. It is important, however, that these can be operated at low voltages too.

It was also stated that the new electrolyte could double the storage capacity of ultracapacitors (double the energy density).

Ultracapacitors (otherwise known as supercapacitors) have some great advantages over batteries, such as the ability to charge in seconds and discharge all of their energy in a matter of seconds at greater than 90% efficiency, and without overheating like batteries would.

This is just a more complex way of saying that ultracapacitors are very powerful, and they can provide a large burst of energy in a short period of time. Ultracapacitors also have a much longer lifespan than batteries. However, they are much more expensive and are also much heavier than most mainstream batteries.

But doubling the storage capacity of ultracapacitors could go a long way in making them more competitive.

Charge Time is of Paramount Importance to Range Anxiety and the Mainstream Adoption of Electric Vehicles

People give me a strange look when I say this, and you are probably wondering why this is so important. It is not just a matter of convenience, but also a pragmatic issue. The two primary reasons why electric vehicles need a long driving range per charge are because it is so inconvenient to sit at a power outlet in public while they take 3-8 hours to charge (less if there is a charging station set up).

So, people have to be able to drive to their destination on their overnight home charge. Otherwise, they will be late for whatever they are trying to get to.

A fast charge time in the order of seconds enables electric vehicle owners to drive their vehicles with a small fraction of the batteries that are in use today, which translates into a much shorter driving range per charge, but, at least, assuming that charging stations are as ubiquitous as gas stations, this would not be an issue for most people because they could simply charge in seconds and be on their way, even if their driving range was only 20 miles!

A smaller battery pack would cost much less too, and the cost of electric vehicle batteries can be 40% of the whole vehicle cost, so short-range batteries can drastically cut the cost of electric vehicles.

There is more good news — li-ion battery technology that charges in only a few minutes already exists. Even if it was more expensive per kWh of storage capacity than typical batteries, the technology could still end up costing less overall because less of them would be required.

Conclusion: The driving range issue is actually a charge time issue, and the improved performance of the electrolyte mentioned above could make electric vehicles lighter, and reduce their battery requirements, since they will have less battery weight to carry around. They also wouldn’t need the extra-large batteries that high performance cars use to achieve high speeds.

h/t Technology Review
Photo Credit: cliff1066™

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Tags: Boulder Ionics, EV batteries, supercapacitors, ultracapacitors

About the Author

Nicholas Brown writes on CleanTechnica, Gas2, Kleef&Co, and Green Building Elements. He has a keen interest in physics-intensive topics such as electricity generation, refrigeration and air conditioning technology, energy storage, and geography. His website is: Kompulsa.com.

DavidSnydacker

Ionic liquid electrolytes allow new high-voltage cathode materials to operate more reliably without damaging the cell. New high-voltage/high-capacity cathodes, like the one developed at Argonne National Lab, will help double the energy density of Li-ion batteries. This will make 200 and 300 mile EVs affordable. But ionic liquids are not directly related to charging time.
Anne

I have been harping on about fast charging too. You see a lot of uninformed people around the Internet clamoring for a 300 mile battery, or a 500 mile battery, or even a 1000 mile battery (really!). But even a 1000 mile battery will not take you everywhere you want to go.

The best antidote against range anxiety is ubiquitous fast chargers. I would say that every petrol station along the motorway should have one, just as you can count om them all selling petrol and diesel. That takes the planning out of longer trips. You just hop in and drive and when it’s time to charge, you simply pull into the next petrol station.

At today’s state of EV technology and charging infrastructure you still have to plan longer road trips. This is a killer. I think people can get over short range, but they just won’t accept having to meticulously plan each journey, nor being limited in where they can go in their car.

Well now, about the charge time of ‘seconds’ that the author is talking about. That is really a bit short. Charging a LEAF battery in 20 seconds would take ~4 MW of power. That requires an industrial grade grid connection or a buffer battery in the charging station. Not to mention the thickness of the cable that will have to carry a cool 10 kA.

I would say a battery with a 200 mile real-life range and a charging time of 15 minutes would be fairly close to what is needed for mass acceptance. People have to pause anyway for reasons that are biological in nature…
- http://cleantechnica.com/ Zachary Shahan
  
  “I would say a battery with a 200 mile real-life range and a charging time of 15 minutes would be fairly close to what is needed for mass acceptance. People have to pause anyway for reasons that are biological in nature…”
  
  Totally agree. This is the target, imho. And those quick chargers being nearly ubiquitous, as you write at the beginning.
anderlan

Charge time also depends on the power level at the charge “pump”. At the house, most folks aren’t getting 240V or larger chargers, instead going with their house’s wiring, with a dedicate 20A circuit. This is the bottleneck, right now.

You’re right, with more commercial charging stations, quick charging could be a real EV win. But it won’t come right away, so I don’t presently see manufacturers going below 75 miles of energy storage in their vehicle batteries. (Though I wish they would–my commute is 6 miles, and a smaller battery makes a cheaper car! More EV models should offer multiple battery-pack sizes for multiple price points.)

I can’t foresee precisely how it will play out, but it is vital that we find ways to fully exploit new fast-charging and discharging (i.e., power-dense) batteries.
- http://cleantechnica.com/ Zachary Shahan
  
  “More EV models should offer multiple battery-pack sizes for multiple price points.”
  
  Love that idea! Would love to see that as well. Wonder when they will decide there is a market for that worth testing options on.