How the hottest lithium ion battery drives the fut

Lithium ion battery: how to drive the future

electric vehicles will develop on a large scale in the coming decades. According to IEA prediction, by 2030, the global ownership of electric vehicles will increase from 3.7 million in 2017 to 130 million, and the annual sales volume will reach 21.5 million. Under this scenario, the annual new battery capacity will increase from 68 GWH in 2017 to 775 GWH in 2030, of which 84% will be used for light vehicles. China, the European Union, India and the United States account for 50%, 18%, 12% and 7% of the demand respectively

in the past two decades, with the expansion of production capacity, the lithium-ion battery technology, which dominates the battery of electric vehicles, has increased significantly, and the price has decreased significantly, making the cost performance of electric vehicles compete with fuel vehicles

key drivers

since its inception in 1990, lithium-ion batteries have been widely used in consumer electronics, energy storage (household, utilities), and electric vehicle industries. With the expansion of production capacity, its performance has been greatly improved and its price has decreased significantly

in the future, the four key factors driving the cost reduction and performance improvement of lithium-ion batteries are: chemical materials, battery capacity, production scale and charging speed

chemical materials. The performance of the battery is affected by 1. The structure of steel strand is generally divided into 1x2, 1x3 and 1x7 bipolar chemical materials. Cathode materials mainly include lithium nickel manganese cobalt (NMC), lithium nickel cobalt aluminum oxide (NCA), lithium manganese oxide (LMO) and lithium iron phosphate (LFP); Most anode materials are graphite, and lithium titanate (LTO) will also be used in heavy vehicles to increase the service life of the circulating fixture. The main advantage of NMC and NCA technology is higher energy density, which dominates the light battery market; LFP has low energy density, but thanks to its higher cycle life and safety performance, it has become the main chemical used in heavy-duty electric vehicles (i.e. passenger cars). Chemical materials have a great impact on the cost of batteries. The price difference of batteries with different chemical materials can reach up to 20%

battery capacity and size. The battery capacity of electric vehicles varies greatly. The battery capacity of the three best-selling small electric vehicles in China is 18.3-23 kwh; The battery capacity of medium-sized vehicles in Europe and North America is 23-60 kwh; The battery capacity of large cars is between 75-100 kwh. The larger the battery capacity, the lower the cost. It is estimated that the unit energy cost of a 70 kwh battery is 25% lower than that of a 30 kwh battery

production scale. Expanding production scale to achieve economies of scale is another important factor. At present, the capacity range of typical factories is about 0.5-8 GW/year, and the capacity of most factories with the largest population is about 3 GW/year. According to the typical capacity of 20-75 kwh of a single electric vehicle, the capacity of a single factory is equivalent to 60-400000 battery packs per year. At present, Germany, the United States, China, India and other places are building a number of battery factories with greater capacity, including Tesla's super factory with an annual capacity of 35 gigawatt hours

charging speed. Current technology can charge 80% in 40-60 minutes. This demand increases the complexity of battery design, such as reducing the thickness of the electrode, which will increase the cost of the battery; Reduce the energy density of the battery, thereby shortening the life of the battery. An analysis by the U.S. Department of energy shows that changing the battery design to adapt to the charging of 400 kW will nearly double the battery cost

material revolution dominates the future trend

according to the analysis of IEA, lithium-ion batteries will still dominate in the next two decades, but their chemical materials will gradually change

around 2025, a new generation of lithium-ion batteries with low cobalt, high energy density and cathode lithium nickel manganese cobalt (NMC) 811 will enter mass production. Adding a small amount of silicon to the graphite anode can increase the energy density by 50%, and the electrolyte salt that can withstand high voltage will also help to improve the performance

from 2025 to 2030, lithium-ion batteries with lithium metal as cathode and graphite/silicon composite as anode may enter the design stage, and even solid electrolytes can be introduced to further improve energy density and battery safety. In addition, lithium ion technology may be replaced by lithium air, lithium sulfur and other batteries with higher energy density and lower theoretical cost. However, the development level of these technologies is still very low, and the actual performance remains to be tested

in the main journal of nature published on July 26th, 2018, an article entitled "ten years left to redesign lithium-ion batteries" pointed out that the evolution speed of lithium-ion battery performance and price is slowing down. The main reasons for the above problems include: in the crystal structure of electrode materials, the amount of charge that can be stored is close to the theoretical maximum; The growth of market scale is difficult to continue to bring substantial price reduction. Worse, electrode materials commonly used at present, such as cobalt and nickel, are scarce and expensive. If there is no new change, it is expected that the demand for cobalt and nickel will exceed the output from 2030 to 2037 (or earlier). On the other hand, new alternative electrode materials, such as iron and copper, which are abundant in reserves, are still in the early stage of research. The article calls on material scientists, engineers and funding agencies to increase the research on electrode materials based on abundant reserves of iron, copper and other materials, otherwise, the large-scale development of electric vehicles will be limited

measurement of economy

the main factors affecting the cost of electric vehicles and fuel vehicles include: battery price, body size (which affects fuel economy and battery size of electric vehicles), fuel price and annual mileage

in terms of battery price, for batteries with lithium nickel manganese cobalt 811/graphite as electrode material, capacity scale of 7.5-35 GW/year and battery capacity of 70-80 kwh, the cost can be reduced to 100-122 dollars/kWh by 2030, which is very close to the cost reduction targets of the European Union (93 dollars/KWH), China (116 dollars/kWh) and Japan (92 dollars/kWh)

the cost gap between electric vehicles and fuel vehicles will gradually decrease with the increase of mileage, but the impact of battery price and gasoline price on this gap exceeds the size of the body. For example, if the battery price is equal to 400 US dollars/kWh, the competitiveness of electric vehicles is very small, and fuel vehicles will be a more economical choice

if the battery price of electric vehicles is low, the price of gasoline is high, and the daily mileage is high, it is more economical to choose small electric vehicles or plug-in hybrid vehicles than small fuel vehicles. For example, if the battery price is $120/kWh and the gasoline price is higher than today's level, pure electric vehicles will be a more economical choice regardless of the mileage. If the price of the battery is equal to 260 dollars/kWh, the driving distance is more than 35000 kilometers. It is necessary to specify the location of the sample and the direction of the metallographic grinding surface/year. When the oil price reaches 1.5 dollars/liter, it is a more economical choice

for large electric buses, if the battery price is less than 260 US dollars/kWh, electric buses that travel 40000-50000 kilometers/year have cost competitiveness in areas with high diesel tax system