The bottleneck of the development of electric vehicles-batteries
How electric vehicles replace fuel vehicles? two basic breakthroughs must be achieved. The first is to get rid of dependence on subsidies, and the second is as economical as fuel vehicles. China’s subsidies for new energy vehicles are expected to withdraw in the last two years. At present, the first half of the battle is over. Under the leadership of Tesla, major manufacturers are basically ready for the second half of battle.
The main problem that electric vehicles can’t completely replace fuel vehicles is mileage, and the key factor in determining mileage is batteries.
First of all, let me give you a few concepts. We know that a general household passenger car usually has a fuel tank capacity of about 55L. According to the fuel consumption of 8L per 100 kilometers, it can run about 600 kilometers. In order to achieve the replacement of fuel vehicles, electric vehicle manufacturers have the basic goal of running 600 kilometers with a single charge.
In order to achieve this 600-kilometer mileage, electric vehicle manufacturers must work hard on batteries.
In theory, you can stack enough batteries to achieve this goal, but we know that the batteries themselves also have weight, so manufacturers must find a balance between long mileage, vehicle weight and battery efficiency. This balance point is what we call the efficiency of battery packs.
So how much improvement does the power battery technology need to make to truly replace fuel vehicles? At present, the consensus answer is that the energy density of the battery system need to be 1.5 times of existing electric vehicles, from the 160wh/kg to 400wh/kg, which is the beginning of the complete replacement of fuel vehicles by electric vehicles. This indicator means that the mileage of battery is 600km, with an electricity of 80 degrees, and a total weight of about 200kg. Now the weight is about 450-550kg.
Our current mainstream batteries, whether LiFePO4 batteries or ternary lithium-ion batteries, are lithium-ion batteries with liquid electrolyte. The theoretical maximum energy density is 350wh/kg, and with various battery management systems, it is almost the limit being able to achieve 300wh/kg for the whole system.
Therefore, the final solution to the problem of battery energy density must be solid-state batteries.
Solid-state batteries are still on the way to research and development. So can we achieve this indicator?
Yes. Engels said, “when there is a technological need in society, then that need will do more to move science forward than ten universities.” Demand is the best motivation. Compared with fuel vehicles, electric vehicles have more space and potential.
According to BloombergNEF data, in the past 10 years, the energy density of batteries has basically tripled. This also shows how fast the industry is progressing, driven by strong demand.
In general, if the energy density of the battery system is not greatly improved, and the level of 400wh/kg cannot be exceeded, it is still a tactical improvement, and there will not be much change in the pattern.