Lithium iron phosphate VS. ternary VS. solid lithium: what is the future of power batteries?

Today, under the guidance of the electric car development, the progress of the power battery is there for all to see. Now on the market are mainly two kinds of batteries, the ternary lithium batteries and lithium iron phosphate batteries and great potential for solid-state batteries are people pay more and more attention to.

January 2017-7 batch of new energy car battery of recommended directory car than analysis:

Strongly supporting the new energy vehicles in the country, only 2017 countries introduced 16 related policies. The new energy vehicles also took advantage of the rapid development with the wind. Market this year is expected to 700000 new energy car production and sales, to drive the demand for power battery will further enlarge. But in the downstream of the upstream raw material prices and OEMS price down under double pressures, the market expected, after brief boom period, cost and technical guidance will make power battery will enter the industry reshuffle.

One of the important bottleneck of new energy vehicles is the range of the battery.In this background, the national action plan for promote the development of automobile power battery, "energy saving and new energy automotive technology roadmap" and so on are encouraging the use of high energy density batteries, recently the foreign investment industrial guidance catalogue (2017 years) is proposed to remove the pure electric vehicle joint venture restrictions and automobile electronic and power battery shares of restricted, is to promote the domestic new energy automobile market popularization and application of high energy density batteries.

At present, most domestic new energy vehicles in the lithium iron phosphate (BYD) and ternary lithium batteries, passenger car range basically can reach 200 km, but the average energy density of battery system level is only 115 wh/Kg.

In March 2017, the state ministry of industry and other four ministries jointly issued "promote the development of automobile power battery action plan", points out that in 2020, requires new lithium ion power ShenChi monomer ratio energy more than 300 wh/Kg;Strive to achieve specific energy system 260 wh/Kg.

Lithium iron phosphate

Lithium iron phosphate batteries using lithium iron phosphate (LiFePO4) as the anode material.

Lithium iron phosphate crystals in P - solid O key, so in zero voltage does not have leakage, when stored in high temperature conditions or overcharge when security is very high, can fast charge, high discharge power, no memory effect, high cycle life and disadvantages for the low temperature performance is poor, the anode material tap density is small, the energy density is low, the yield of the product and consistency is also in question.

Lithium iron phosphate batteries needed without having to import raw materials, supply adequate, stable prices, the cost is relatively low.The cycle of phosphoric acid lithium battery life is far greater than the ternary lithium battery.

Disadvantages: low temperature conditions (air temperature is below - 10 ℃), phosphate lithium battery decay very fast, after less than 100 times charging and discharging circulation, battery capacity will fall to 20% of the initial capacity, the use of cold region and basic insulation.The anode material tap density is small, the energy density is low, the yield of the product and consistency is also in question.

Lithium iron phosphate battery monomer energy density of 140 wh/kg, already close to theoretical limits 170 wh/kg.

The ternary lithium battery

The ternary lithium battery full name is"Batteries ternary material", generally refers to using nickel cobalt manganese acid lithium (Li (NiCoMn) O2, sliding) lithium nickel or cobalt aluminate (NCA) ternary cathode material of lithium-ion batteries, nickel salt, manganese and cobalt salt salt as the proportion of three different components to different adjustment, so called "three yuan".

Advantages: three yuan in the low temperature performance of lithium-ion batteries, under the condition of - 30 ℃ can keep the normal battery capacity, to meet the conditions of use of the northern cold region.Three yuan battery energy density of 180 wh/kg, and a lot of room to improve in the future.

The nominal voltage can achieve 3.6 3.8 V, higher energy density, high voltage platform, high tap density, long range, the output power is larger.

Faults: under the condition of high temperature, the ternary lithium batteries ternary material can cause decomposition at 200 ℃, under high temperature is easily occurred the phenomenon of the combustion or explosion.

On the manufacturing cost of it, the ternary lithium batteries required for cobalt element resource in our country, to overseas, most affected by market volatility is very large, so the ternary lithium batteries cost is high.

Ternary lithium battery products have been mature, the tesla Model series models have a breakthrough, the Model3 soon scale sales, further argument ternary lithium power battery feasibility of.Model3 with new batteries, 21700 compared to 18650 batteries in appearance change long thick, the energy density is increased by 20%, single battery capacity is 3 ~ 4.8 Ah, a sharp increase of 35%.There is no doubt that the current ternary lithium power battery is for the mainstream products.

Solid state lithium battery

In addition to the mainstream in the market now ternary lithium battery and lithium iron phosphate batteries, increasingly taken seriously by people solid-state lithium battery is referred to as the battery star of the future.

The traditional liquid lithium battery was known as the "rocking-chair batteries", the ends of the rocking chair for the battery positive and negative poles, for liquid electrolyte in the middle.Lithium ion as an athlete, running back and forth on both ends of a rocking chair, lithium ion from the positive to the negative to the positive movement in the process, the battery charge and discharge process is completed.And solid-state batteries for solid state electrolyte, with density and structure allows more charged ions gathered at one end, conducted a larger current, to increase the battery capacity.

Potential from a technical perspective, the ternary lithium power battery energy density increase is relatively difficult, all solid state lithium battery energy density increase, theoretically more feasible.Is a solid-state lithium battery voltage platform ascension, solid electrolyte is more common than organic electrolyte wide electrochemical window, is conducive to further enhance the energy density of battery,2 it is a solid electrolyte can cut off lithium dendrite growth, material scope of application system, for the new li-ion battery with higher energy density of space technology lay the foundation.Three are all solid state lithium battery energy density of about 400 wh/Kg, current estimates maximum potential value of 900 wh/Kg, more than 100% of room for improvement.

Solid state lithium batteries based on lithium battery has the merits of the traditional inheritance, security, a massive progress in energy density, etc.At present, the solid-state lithium battery research and development can provide basic energy density can be up to 300 ~ 400 wh/kg, it is expected to be as the next generation of high energy density of power and energy storage battery technology important development direction, is the consensus of academia and industry.

To sum up, the lithium iron phosphate technical route is replaced, the ternary lithium battery technology has become mainstream, solid-state lithium battery or new lithium-ion battery technology will gradually replace the ternary lithium.

In the future, health and large-scale application of new energy vehicles, depends largely on the high security, high range of power battery support.At present, new energy automobile power battery technology progress will double by competition from national policy, external pressure drive, which requires the existing ternary lithium power battery technology continues to improve, also need a new lithium-ion battery technology and technological breakthrough, in order to realize the disruptive innovation.Said to power battery enterprise, now is the best of times, also is the worst.

The last:Lithium iron phosphate battery and lead acid batteries comprehensive comparison of the two

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