Thousands of electric vehicles [EV] have been sold in the US, all with the same problem, range and expense. True, current battery technology, lithium-ion [Li-ion] has come leaps and bounds past its predecessors, nickel-metal hydride [NiMH] and nickel-cadmium [NiCad] and even lead-acid.
Each step in battery technology increased the capacity and reduced weight. Still, current Li-ion batteries offer limited EV range. Additionally, lithium is an expensive element, making the Li-ion battery pack in the Nissan Leaf come in at around $12,000.
Battery makers have been working to find the next “game-changing” rechargeable battery technology, such as A123 Systems‘ Lithium-Iron Phosphate [LiFePO4] nanotechnology, which made big promises, but market demand never allowed it to come to market.
Other companies are still working toward a battery technology that will, not only offer increased range, but use less expensive materials. Toyota engineers, who believe that EVs simply won’t take off unless they can promise more than a couple hundred miles range, have released a couple of EVs, but only to limited markets.
Toyota, never one to make drastic steps, has kept reliable NiMH battery technology in all of its hybrid vehicles, from the modest Prius to the luxury Lexus RX 400h, and hasn’t put much research into Li-ion technology. What they have been working on is a new magnesium-ion [Mg-ion] rechargeable battery pack. Toyota’s Mg-ion battery uses a similar electrolyte and cathode as Li-ion, but with a tin anode.
The new Mg-ion battery looks to be less expensive, as magnesium is much more abundant. The new battery should also have a higher energy-density, as magnesium ions have twice the positive charge of lithium ions.
Toyota’s Mg-ion battery technology probably won’t make it to market for at least ten years, so for now, it’s a research project with many interested parties. Mg-ion batteries could probably find their way into consumer electronics long before automobiles.
“Once you have a breakthrough, meaning you have an anode, a cathode, and electrolyte, it takes maybe five years to reach the commercialization stage, and we don’t have all that with magnesium, so it’s going to take a while,” says Venkat Srinivasan, researcher and manager at Lawrence Berkeley Laboratory’s Batteries for Advanced Transportation Technologies program.