What has changed in the controversial power battery war?

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What has changed in the controversial power battery war? [Copy link]

As the core power component of new energy vehicles, the performance of batteries largely determines the overall performance of the vehicle, and there has always been controversy over its technical route. It seems that there has been no definitive answer as to which battery is more suitable for current pure electric vehicles. Due to the different performance advantages of power batteries, fundamentally speaking, the controversy revolves around the issue of battery life and safety factor.

Such battery performance differentiation also causes users to waver in choosing which battery model to use. In the new energy vehicle market, battery safety and battery life cannot be achieved at the same time. If the battery is safe, some battery life must be sacrificed. If the battery life is satisfied, some safety must be sacrificed. Safety and battery life are not only important factors for consumers to consider when buying electric vehicles, but also core elements of the industry's development path.

The current mainstream technical routes are ternary lithium batteries and lithium iron phosphate batteries. Both factions have irreplaceable advantages in their respective fields, and each has its own merits. Everyone has their own opinions and differences. The ternary lithium battery technical route represents the high mileage of electric vehicles, and it is widely used in medium and high-range models. The lithium iron phosphate battery technical route represents better safety and cost performance, and is widely used in medium and low-range models. The faction headed by CATL that pursues a higher mileage has chosen the direction of ternary lithium, while BYD has become the spokesperson for lithium iron phosphate with battery safety as the main focus. So what are the differences and advantages of these two technical routes?

Ternary lithium vs lithium iron phosphate:

Performance comparison

The structures of ternary lithium batteries and lithium iron phosphate batteries are similar. Both are composed of four parts: positive electrode material, negative electrode material, separator and electrolyte. The fundamental difference between the two is the difference in positive electrode materials. The positive electrode material of ternary lithium batteries is a polymer of nickel, cobalt, manganese or nickel, cobalt and aluminum, while the positive electrode material of lithium iron phosphate batteries is lithium iron phosphate.

Ternary lithium battery refers to a lithium salt lithium battery with three elements of nickel, cobalt and manganese (NCM) as the positive electrode material, graphite as the negative electrode material, and lithium hexafluorophosphate as the electrolyte. It is currently mainly used in the electric vehicle industry and is one of the mainstream battery technology routes in power batteries. Lithium iron phosphate battery refers to a lithium-ion battery with lithium iron phosphate as the positive electrode material, graphite as the negative electrode, and lithium hexafluorophosphate as the electrolyte.

The main criteria for measuring whether a battery is good or not are mainly based on four factors: energy density, cycle life, safety and cost. Energy density is divided into single energy density and system energy density. Single energy density refers to the energy released per unit volume or unit mass. This parameter is a direct factor affecting the endurance of electric vehicles. When we discuss the energy performance of the entire vehicle, we use system energy density.

Cycle life refers to the number of cycles or cycles that a battery undergoes after repeated charge and discharge. After repeated charge and discharge, the capacity of the battery will gradually decrease. Under certain discharge conditions, when the battery capacity drops to 80%, the number of cycles the battery has undergone is the cycle life. Safety is also about the thermal runaway problem of the battery. When the thermal runaway of the battery reaches a certain temperature, an uncontrollable state will occur, causing the temperature inside the battery to rise sharply, and there may be a risk of combustion or explosion.

In general, the main advantage of ternary lithium batteries is their high energy density, which allows cars to have a longer range and solves the core mileage problem of electric vehicles. However, their safety is widely criticized. Their thermal runaway temperature is lower than that of lithium iron phosphate batteries. The thermal runaway temperature of lithium iron phosphate batteries is around 500°C, while that of ternary lithium batteries is around 300°C. In the thermal runaway temperature range, the electrolyte will burn rapidly, creating the risk of spontaneous combustion and explosion. There are frequent spontaneous combustion accidents and recalls of ternary lithium battery cars. The most recent large-scale recall of new energy vehicles was also due to battery safety. Due to a series of fire incidents in Hyundai Kona cars, in February this year, Hyundai Motor and LG Chem spent US$900 million to recall 82,000 vehicles worldwide to replace their battery systems to improve safety performance.

In terms of battery safety, lithium iron phosphate batteries have advantages. Even if they are damaged internally or externally, the batteries will not burn or explode. Moreover, the batteries do not contain any heavy metals or rare metals, are low in cost, and are pollution-free and environmentally friendly. Of course, lithium iron phosphate batteries are not perfect. The main disadvantage is that the energy density is lower than that of ternary lithium batteries. However, ternary lithium batteries can continue to upgrade their energy density by adjusting the proportion of nickel in the positive electrode material.

In addition to energy density, its low temperature resistance is also poor. Under low temperature conditions below -10℃, lithium iron phosphate batteries decay very quickly. After less than 100 charge and discharge cycles, the battery capacity will drop to 20% of the initial capacity, which greatly limits its use in low temperature weather in the north. However, ternary lithium batteries have excellent low temperature performance and can maintain normal battery capacity even under -30℃ conditions, making them more suitable for use in low temperature areas in the north.

In summary, ternary lithium batteries are widely used in medium and long-range vehicles due to their high energy density, while lithium iron phosphate batteries are widely used in medium and low-range vehicles due to their longer life and lower cost. At present, most companies are still focusing on ternary lithium batteries. Domestic power battery companies such as CATL, AVIC Lithium Battery, and EVE Energy are all focusing on ternary lithium battery products. Foreign power battery companies such as Panasonic, LG Chem, and Samsung SDI also adopt the technical route of ternary lithium batteries.

New changes in the power battery landscape,

Lithium iron phosphate quietly rises to the top

Looking at the development path of power batteries, it is interesting to find that these two power battery technology routes present a changing path that alternates back and forth. From the development history of power batteries, before ternary lithium batteries became popular, consumers did not have such high demands for the range of electric vehicles. In addition, its cost was lower than that of ternary lithium batteries. Lithium iron phosphate has actually always been the main technology route for power batteries. However, later, due to the energy density performance of ternary lithium batteries and the importance of endurance on the consumer side, the market trend turned to ternary lithium batteries.

Thirty years on the east side of the river, thirty years on the west side of the river. Fortunately, we are standing at the turning point of technology and policy again. The subsidy policy for new energy has gradually declined in recent years. The state's subsidies for batteries have become less and less, and the price of power batteries has more and more directly affected the cost of electric vehicles. In the context of new energy vehicles emphasizing high-quality and low-cost development, the development pattern of lithium iron phosphate batteries and ternary lithium batteries is facing new changes. Under the policy of unfavorable subsidies, the cost advantage of lithium iron phosphate over ternary lithium batteries is evident. The lithium iron phosphate battery after technological innovation has broken its original range bottleneck and can meet the requirements of 400km-600km range. In view of the significant optimization of battery performance and its original cost advantage, car companies are also gradually taking lithium iron phosphate batteries as a new choice, and lithium iron phosphate batteries are gradually becoming more popular.

According to the latest data released by the China Automotive Power Battery Industry Innovation Alliance, in May 2021, my country's monthly output of lithium iron phosphate batteries exceeded that of ternary lithium batteries for the first time. As of the end of 2020, the output of ternary lithium batteries and lithium iron phosphate batteries in my country accounted for 58.1% and 41.4% respectively. From January to May 2021, the cumulative output of lithium iron phosphate batteries in my country accounted for 50.3%, exceeding the 49.6% of ternary lithium batteries.

We can see that the output of lithium iron phosphate has exceeded that of ternary lithium batteries in the first half of the year. Although this data is battery output rather than market share or installed capacity, its growth trend can also be predicted. The installed capacity of lithium iron phosphate will most likely exceed that of ternary lithium batteries in 2021. For electric vehicles, choosing the technical route of ternary lithium batteries is also the optimal solution in line with its cost and technical advantages.

From the perspective of industrial layout, leading battery companies such as CATL, BYD, and Guoxuan High-tech are actively increasing their investment in lithium iron phosphate battery production capacity. The CTP batteries and blade batteries based on lithium iron phosphate solutions launched by CATL and BYD have also been recognized by the market. Manufacturers are actively expanding and deploying their lithium iron phosphate battery production capacity to gain first-mover competitive advantages.

The route dispute has no end.

Innovation and transformation are on the way

From the perspective of time span, the technical route of power batteries in the market has always been a swaying situation. At present, due to new changes in the policy environment and technological innovation, lithium iron phosphate batteries have opened up a new power battery pattern and taken the lead. However, we also know that there is no permanent first in any ranking. In addition to the top performance of ternary lithium batteries and lithium iron phosphate batteries, there are also some new technologies and developments in power batteries that have new changes and innovations, which are worth paying attention to. No one can be sure what the mainstream trend will be in the future, but based on the innovation points of these technologies, we can also get a glimpse of the general development outlook.

Solid-state battery is an emerging technology. Solid-state battery technology uses glass compounds made of lithium and sodium as conductive materials, and uses solids to replace the electrolyte of previous lithium batteries. In addition to avoiding electrolyte leakage, better controlling volume, and achieving more dense energy storage, it can also serve as a battery diaphragm to reduce the risk of fire and explosion. Solid-state batteries have a long cycle life. The current expected life span of research and development is 15,000-20,000 times, which is much higher than the 1,200 times of ternary lithium batteries and 2,000 times of lithium iron phosphate batteries. All performance parameters are currently the results of laboratory tests and have not yet been truly mass-produced for commercial use. The main reason is that its production process is complex and the cost is high. Because of its performance advantages, major manufacturers are currently actively planning the deployment of solid-state battery research and development.

In addition to the solid-state batteries that are being studied, a battery between liquid and solid - the jelly battery - is also gradually coming into view. This is a gel battery based on cobalt-free cathode materials and electrolyte materials, developed by battery manufacturer Honeycomb Energy. This gel electrolyte can better fit the surface of the electrode material, has the characteristics of self-healing and flame retardancy, and can prevent heat diffusion without reducing electrical performance. Jelly batteries can be said to be a transition from liquid batteries to solid-state batteries.

Another new power battery product on the market is the quaternary lithium battery, which refers to a battery with four metal materials, nickel, cobalt, manganese and aluminum, in the positive electrode. The quaternary lithium battery is an upgraded version of the ternary lithium battery. The nickel content is increased, and more aluminum is added, which reduces the content of other high-value metal elements, achieving high energy density, high stability and low cost, which are difficult to achieve at the same time. It is currently being developed by South Korea's LG Chemical battery manufacturer and is reportedly ready for mass production and installation as early as this year. For power battery products, their mass production will set off a wave of technical route upgrades.

In addition to innovations in materials, structural innovations also have new highlights. At the end of March 2020, BYD officially launched the "Blade Battery". Through structural innovation, modules are eliminated, the length of the battery cell is increased, and the volume utilization rate is improved, which not only meets the requirements of battery stability and safety performance, but also effectively improves the driving range. Under the premise of using lithium iron phosphate cells, the blade battery structure raises the capacity (battery life) level of lithium iron phosphate batteries to the same level as ternary lithium batteries. In the future, BYD claims that all of its electric vehicles will be fully equipped with blade batteries, and it is currently actively expanding production capacity.

In general, the new technologies mainly focus on material and structural innovation. In terms of materials, the electrolyte is developing towards a solid-state route around the removal of cobalt, high nickel, and the addition of silicon. The structure is developing towards a de-modularized CTP and CTC route (that is, the core eliminates the battery module and packaging process, and directly integrates the battery cell into the car chassis to achieve a higher degree of integration).

Regardless of the direction of technological development, the purpose is to enhance battery performance and safety. We know that there is still a large gap between the performance of laboratory products and the products after they are officially launched. In the meantime, it is necessary to constantly balance the conflicting performance indicators such as energy, life, cost, and safety. Although lithium iron phosphate has gained an advantage in the current technical route competition, and lithium iron phosphate batteries will have more installed capacity in electric vehicles in the foreseeable future, we have also found that the technology of power batteries has been innovating and changing, and new products such as solid batteries, jelly batteries, and nano-ion batteries are also gradually dazzling. Maybe one day the technology will develop to break the existing records of cost and mileage. The new battery technology route will reshuffle the electric vehicle industry and bring a safer and more convenient experience to users.

Looking at it from a longer time perspective, the increasingly fierce technological innovation makes the battle over battery routes seem endless. For the industry, the continuous evolution of power batteries brings a safer and more efficient experience, which will also lead to changes in new energy vehicle technology and products, providing users with more choices.

The article comes from Brain Pole (WeChat public account), author Yan Liang