Instead of li-ion they need to work on super capacitors which are better suited for electric cars.
Li-ion batteries have a very low charge cycle. In an all electric car the range is already a major issue, imagine losing 40% of that range after 2-3 years, and having to consider replacing the battery after 5 years or so (the most expensive part of the car)
super capacitors have been tested at 500,000+ charge/ discharge cycles with 0% loss in capacity, they just have a lower energy density than even led acid batteries (making it unfeasible to even use in a truck) but if they put more work on it they may be able to someday get that energy density levels close to that of li-ion batteries.
PS li-ion batteries in cars rarely go below room temperature. cars (eg the ford ones and the tesla ones, rely on active cooling to keep the battery from getting to a unsafe temperature. (if you have no plans to test drive a car, i recommend you test drive some of the electric cars (some car dealerships even give $5 giftcards for test driving a car and listening to a sales pitch) but anyway, test drive a electric car then ask to check the trunk and back seats (you will feel that those areas have gotten pretty warm, that is because li-ion batteries heat up while they are charging and also while they are discharging, and aggressive driving (eg harder acceleration, will heat the battery up very quickly)
In one way it is good for cold areas because you are less likely to be stuck with the cold temperature capacity issue, it also means a shorter lifespan for the car.
Remember, other than using different materials, you cant extend the life of a li-ion battery by much since it is a chemical reaction and chemistry shows that reactions have a limit which can be calculated. (and those calculations are basically the max you can ever hit)