It was not until the emergence of lithium batteries that this problem was solved after 20 years of vigorous development.

Lithium batteries are usually divided into two categories:

Lithium metal battery: Lithium metal battery generally uses manganese dioxide as positive electrode material, lithium metal or its alloy metal as negative electrode material, and uses non-aqueous electrolyte.

Lithium-ion battery: Lithium-ion battery is generally a battery with lithium alloy metal oxide as positive electrode material, graphite as negative electrode material and non-aqueous electrolyte.

Although the lithium metal battery has high energy density, it can theoretically reach 3860 W/kg. However, due to its unstable nature, it is not rechargeable and cannot be reused as a power battery. Lithium-ion battery has become the main power battery because of its rechargeable ability. However, due to the different elements, the performance of cathode materials is very different in all aspects, which leads to the increase of controversy about the route of cathode materials in the industry.

Usually, the power batteries we talk about most mainly include lithium iron phosphate battery, lithium manganate battery, lithium cobaltate battery and ternary lithium battery (ternary nickel cobalt manganese).

The above batteries have their own advantages and disadvantages, which can be summarized as follows:

Lithium ferrous phosphate:

Advantages: long service life, large charge-discharge rate, good safety, good high temperature resistance, harmless elements and low cost.

Disadvantages: low energy density and low tap density (volume density).

Lithium ternary:

Advantages: high energy density and high tap density.

Disadvantages: poor safety, poor high temperature resistance, poor service life, poor high-power discharge, and toxic elements (the temperature of ternary lithium battery rises sharply after high-power charge and discharge, and the oxygen released after high temperature is very easy to burn).

Lithium manganate:

Advantages: high tap density and low cost.

Disadvantages: poor high temperature resistance, the temperature of lithium manganate rises sharply after long-term use, and the battery life is seriously attenuated (for example, the leaf of Nissan electric vehicle).

Lithium cobaltate:

Usually used in 3C products, the safety is extremely poor, and it is not suitable for power batteries.

Theoretically, the battery we need should be high energy density, large volume density, good safety, high and low temperature resistance, long cycle life, non-toxic, harmless, capable of high-power charging and discharging, integrating all advantages and low cost. But there is no such battery at present, so it is necessary to choose between the advantages and disadvantages of different types of batteries. Moreover, different electric vehicles have different demand points for batteries, so only by making a long-term judgment on electric vehicles can we correctly judge the choice of battery routes.