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.
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