When we talk about electric vehicle heat, there is no better than the power battery. Ternary lithium battery and lithium iron phosphate battery are the two major directions of mainstream technology. Then, what are their advantages and disadvantages? This article brings us a comprehensive interpretation.
1.Electric Vehicle Heart
According to public information, power batteries are divided into chemical batteries, physical batteries, and biological batteries, while electric vehicles use chemical batteries, which are the source of vehicle driving energy and can be called the heart of electric vehicles. The structure of the battery can be divided into two categories: Battery and fuel cell. The battery is generally referred to as the rechargeable battery. There are NI-MH battery, lithium-ion battery, lithium polymer battery, and Lead-acid battery, etc. Because of its high energy density and long cycle life, the lithium-ion battery has become the most common battery for electric cars and most electronic products.
2. How to evaluate power battery performance?
It is well known that the lithium-ion battery consists of cathode material, anode material, diaphragm and electrolyte, of which the cathode material costs up to 30%, and is currently the key to improving battery performance. According to different materials are divided into lithium titanate, lithium cobalt, lithium manganese oxide, nickel cobalt manganese(NCM) and lithium iron phosphate(LFP). NCM battery and LFP battery are the most popular and famous & popular batteries around the world.
People in the industry field pointed out that the performance indexes of power batteries mainly include five dimensions: Energy Storage density, cycle life, charging speed, resistance to high and low temperatures and safety. Among them, energy storage density and safety are the two most important requirements. Lithium titanate batteries and lithium manganese batteries were discarded because of their low energy storage density, while lithium cobalt batteries were shelved because of their poor safety, leaving only NCM and LFP batteries to enter the mainstream market. Apply to the passenger car market and energy storage market respectively.
3.NCM battery VS LFP battery?
In fact, NCM battery and LFP battery are not absolutely good or bad, but each has its own merits.
The advantages of the NCM battery lie in two aspects: Energy storage density and low-temperature resistance.
Firstly, for energy storage density, the NCM battery has a higher voltage and its energy density can basically reach 240WH / kg, which is nearly 1.7 times of LFP battery density 140WH / kg.
Secondly, the low-temperature limit of the NCM battery is -30℃, which is more advantageous than the low-temperature limit of -20℃ of the LFP battery. At the same low-temperature condition, the attenuation of NCM battery in winter is less than 15% obviously better than the LFP battery attenuation up to 30%, more suitable for the northern market, which is why NCM battery sells well in the south, but it is difficult to open the market in the north.
However, LFP battery also has three advantages.
One is high safety performance, because the temperature of the LFP battery thermal runaway is generally above 500℃, and the temperature of NCM batteries is below 300℃. Some high-nickel batteries even below 200℃. Compared with NCM batteries, LFP batteries for vehicle high-speed driving and rapid charging process can highly reduce the spontaneous combustion risk.
The second is longer cycle life. LFP battery charge and discharge cycle number more than 2000 times before it decays,while the NCM battery charge and discharge cycle life is only 500 times, which shows the difference between the two.
The third is that the manufacturing cost is lower. because the LFP battery has no precious metal, so the production cost is lower. On the other hand, the NCM battery is made of cobalt, and 70% of its reserves are in Congo, Africa, which makes its import price skyrocket. The current price has reached $38,000 USD/ ton. LFP battery is more economical sometimes.
SmartPropel Original Work Writer：Nancy