Published August 10, 2012
By Philippe Crowe
Spending time at the wheel of many electric and hybrid cars in the last few months got us wondering where lithium-ion batteries are headed. Our research led us to some noteworthy finds.
There is a consensus: lithium-ion is the winning type of rechargeable battery for this decade. IDTechEx counted about 150 manufacturers of these and expects to see 200 manufacturers of lithium-ion batteries soon, mainly because of the burgeoning number of Chinese companies making poor quality me-too-but-cheaper versions.
Everyone also agrees that traction batteries for electric vehicles - hybrid and pure electric - will be the major market for lithium-ion batteries over the coming decade. It is also expected that electric vehicles will dominate the use of this type of batteries in later years by a big margin.
One well balanced article that summed up very well our other findings was written by Dr Peter Harrop, the Founder and Chairman of IDTechEx.
The full article can be accessed here and the following paragraphs represent some of the key points he made.
Dr Harrop says IDTechEx projects a market for traction batteries in land and water vehicles plus aircraft of just under $60 billion in 2020 of which about 60% will be lithium-ion. IDTechEx also expects 80% of those will be made by just four winning lithium-ion manufacturers.
An important element to consider in order to understand the scale of the market is the fact electric vehicles need the equivalent of thousands to tens of thousands of mobile phone batteries per vehicle.
The disagreement amongst the battery community comes with just about everything else concerning lithium-ion batteries.
The chemistry front is the big question mark – and also where the solution likely rests; both the cathode and the anode need improvements.
There is lithium iron phosphate used for active cathodes because of advantages such as no materials subject to severe price hikes, low cost materials and easier patent position.
Batteries conceived this way have good temperature performance that can reflect in greater safety, though no lithium-ion cell is inherently safe and the first defender of safety is the Battery Management System BMS, not the cell.
On the anode side, today’s batteries have little more than copper foil coated with carbon such as graphite. Disagreement reigns on how to improve this aspect. EnerDel, Altairnano and Toshiba have taken the lithium titanate route said to improve power density for fast regenerative braking and fast chargers at the roadside or bus depot.
Other organizations are now looking at silicon-based anodes. It is argued that silicon can increase cycle life and even that vital energy density but does vanadium need to be involved? Nanotechnology? Graphene? Struggling for any agreement here, Dr Harrop can only say that most experts believe that the cleverer anode will cost more than its typically 14 percent of cost reported today; but it will never cost as much as the cathode, with 35 percent of the total spend.
It is clear that the main frontier of lithium-ion success is achieving affordably greater energy density, which will translate into greater range for the vehicle’s end user.
It is stating the obvious to say that there will be a huge take-off in sales when most people think the range of an affordable pure electric car is adequate. But what is adequate?
Any improvement will create a significant rise in sales, but no one knows or agrees on what this tipping point may be.
We can only agree with Dr Harrop when he states that “nobody knows that figure for widely acceptable range partly because there is almost no statistical correlation between how people respond to questionnaires and what they then do.”
Alternatively, how far does the price of lithium-ion batteries need to fall for the electric vehicle to become viable on a large scale?
Analyst Pike Research puts that at about $523 per kilowatt hour by 2017… aren’t we there yet? The Nissan Leaf EV's battery pack has been reported to cost only $375 per kilowatt hour. On Tesla Motors’ front, CEO Elon Musk said recently that battery costs may fall to less than $200 per kilowatt hour “in the not-too-distant future.”
On the other hand, success may go towards avoiding a battery. Supercapacitors and the half-way solution of the supercabattery (Asymmetric Electrochemical Double Layer Capacitor), notably the "lithium capacitor" which has one lithium-ion battery electrode, is being studied. The developers of these now outnumber the number of developers of rechargeable lithium/lithium metal batteries.
Dr. Harrop also points to the fact many of the giants spend more than half of their expenditure on electric vehicles that are not cars.
A good example being Toyota which is more than four times as big in electric vehicles as number two partly because it is world number one in pure electric and hybrid forklifts and near the top in hybrid electric buses.
As is often the case, success may come by ignoring trends and aiming for the best viable technology.
