Over the years, one of the characteristics of the development of the battery industry is that technology iteration is very fast. Initially, Ningde Time launched CTP technology, followed by BYD's blade battery shouting loudly, and now JAC has a honeycomb battery. The three battery technologies are all innovations and innovations at the application level.
The CTP technology (CELL TO PACK, module-free technology) launched by Ningde Time has revolutionized the original battery assembly, and BYD's blade battery is also a module-free technology. JAC's honeycomb battery is arranged according to hexagonal shape and uses NCA (nickel-cobalt-aluminum) cells, which improves safety by an order of magnitude.
So if all three electronic technologies will be market PK, who will win?
CTP technology first mover advantage
The person in charge of Ningde Times CTP project team told China Automotive News that after adopting the module-free technology, the battery pack volume utilization rate has increased by 15% to 20%, the number of battery pack parts has been reduced by 40%, and the production efficiency has been improved by 50%, which will significantly reduce the manufacturing cost of power batteries.
The advantages do not stop here, improve the volume utilization of the battery pack will undoubtedly increase the internal space capacity of the vehicle, so that the driver no longer feel confined; reduce the intermediate links, production efficiency will also be significantly improved. Generally speaking, the production process of power batteries, each process has a detection gate, the previous production method is the battery cell through a certain framework to form a module, the module must be tested off-line, and then stored and transferred. If the battery pack and the module are not in the same factory, before producing the battery pack, the production workshop must again carry out incoming inspection and on-line inspection of the incoming module. With the removal of modules, the production efficiency will be significantly improved.
Most importantly, after adopting module-free technology, the system energy density of the battery pack has been greatly improved. The person in charge told the reporter that the energy density of module-less battery pack has increased by 10%~15% compared with traditional battery pack, and the energy density of traditional battery pack is 180Wh/kg on average, while the energy density of module-less battery pack can reach more than 200Wh/kg.
Although there are many advantages of module-less power battery, but there are also technical safety concerns in the industry. However, the person in charge told reporters that there is no need to worry about safety issues, and the application of module-less technology will also reduce safety risks. He explained that in the past spontaneous combustion of electric vehicles, the cause of fire mostly lies in the thermal runaway of the power battery, and the cause of thermal runaway is that the heat generated by the power battery in the charging and discharging process cannot be evacuated in time. Module-less technology can free up more space for the battery pack because it reduces the amount of parts used in the pack, and the heat dissipation channel of the battery will be smoother.
However, in the past, there were many electric vehicle fires, and some of them were caused by the battery contact parts wearing out due to the vibration generated during the driving of the electric vehicle. The module plays the role of fixing the single battery in the battery pack, can the fixing of the single battery be guaranteed after removing the module? The person in charge told the China Automotive News reporter, in the traditional battery pack, usually using bolts to fix the module, each battery pack has hundreds of bolts, any bolt is not fixed, may bring safety risks. The module-free technology uses other methods, such as new structural glue, limit frame, etc. The glue has a certain ability to absorb vibration, which can relatively slow down the impact of vehicle driving vibration.
In addition, the poor waterproof level has also led to a number of electric vehicle fire incidents in China. The person in charge of Ningde Times CTP project team told China Automotive News that the original functions of insulation, waterproofing, heat diffusion prevention, heating and cooling on the traditional battery pack are not reduced on the module-less battery pack, but rather optimized, and the safety performance is further improved.
Blade battery has a high sound
BYD blade battery cell material is lithium iron phosphate. Lithium iron phosphate has been very hot in recent times, and BYD used a video at the launch to tell everyone how good the safety of lithium iron phosphate is. Safety is to attract attention on the one hand, subsidies are also one of the important reasons for the retreat.
"Blade battery" technology PACK volume energy density of more than 330Wh / L, compared to the original battery system can be improved by more than 30%, by saving materials, labor costs, etc., the battery pack cost is expected to reduce 30%. Because the "blade battery" is thinner than the traditional square battery, so the heat dissipation effect is better.
Combing through the subsidy policy in previous years, we can see that the minimum range threshold is 150 km, later increased to 250 km, the latest subsidy policy adjustment, more prominent the advantages of long range models, range between 250 km to 400 km of pure electric new energy passenger cars, can enjoy a subsidy of 18,000 yuan; range of more than 400 km of pure electric new energy passenger cars, can enjoy a subsidy of 25,000 yuan. The subsidy is 25,000 yuan.
According to a car equipped with 60 degrees of electricity, lithium iron phosphate and ternary lithium battery cost difference of about 18,000 yuan, the range of 250 km to 400 km between the subsidies for 18,000 yuan, subsidies have wiped out the cost gap between the two, more than 400 km to install ternary batteries to get more subsidies, the cost difference is upside down. Driven by the interest, vehicle manufacturers have chosen ternary lithium batteries.
Xue Xu, secretary-general of the Marketing Expert Committee of the China Institute of Marketing and associate professor of the School of Economics at Peking University, told reporters that most consumers are more sensitive to price, especially consumers of low-end models are more sensitive. Most of China's new energy vehicles are concentrated in the middle and low end, and low price is a powerful competitive weapon.
Honeycomb battery reduces the probability of fire by an order of magnitude
"The honeycomb battery adopts the bionic design of honeycomb structure and achieves unitized encapsulation through the UE technology of epitaxial cladding (Unitized Encapsulation)." Zhou Peng, director of JACHT Power, said, "The UE technology can reduce heat diffusion within the battery system and keep the battery system at a constant temperature, reducing the impact of seasonal temperature differences on the battery range."
The cells of the cellular battery are arranged in a hexagonal shape, and the cells are filled with thermal conductive adhesive between them, which ensures the speed of heat dissipation from the cells. The 100% contact between the thermal adhesive and the cells will accelerate the heat dissipation of the cells. The electrochemical reaction of the cells inevitably brings heat dissipation, and the thermal adhesive quickly transfers the heat out to ensure that the temperature difference inside the battery pack is ≤3°C.
The hexagonal structure of honeycomb battery has high stability. The honeycomb of bees is a case of nature, and the hexagonal structure is also used in a large number of engineering constructions. JAC's honeycomb battery also adopts hexagonal structure. Zhou Peng told reporters that the hexagonal structure can attract a certain amount of collision and extrusion energy, and it is not easy to collapse a large area even when encountering large external collision and extrusion.
The cellular battery is filled with heat-conducting adhesive between the cells, so as to achieve electrical and thermal isolation between the battery monomer. If one cell fails, it will not spread to the surrounding area and therefore will not cause a chain reaction. This technology cuts off the path for bad cells to spread to the surrounding area, thus ensuring the safety of the battery pack.
According to the introduction, JAC's cellular battery uses Lixin's 21700 NCA battery, which is designed with double explosion-proof valves, has a capacity of 1C-4.8Ah (0.2C-5Ah) and a single energy density of 245wh/kg. from the energy density point of view, the cellular battery's energy density is in line with the mainstream trend and is in the upper middle level.
Another key of honeycomb battery is that the cell adopts double explosion-proof valves. In the past, cylindrical batteries had only one explosion-proof valve located at the top of the cell. Once thermal runaway occurs inside the cell, the reaction is very violent, and only one end is designed with a valve, which means that gas can only come out from one direction. The double explosion-proof valve is designed to divert the outgoing gas and reduce the intensity.
Why use NCA (nickel cobalt aluminum)? Zhou Peng told reporters that compared to NCM (nickel-cobalt-manganese) batteries, NCA batteries have better safety and stability, but are also more technically difficult. This difficulty covers material technology, battery design and processing technology. Panasonic supplies Tesla's battery is NCA, although Tesla has fire accidents, compared to the proportion of domestic electric car fire accidents is significantly lower.
The cellular battery has undergone several rigorous tests. Heated directly from the bottom with gasoline for 130 seconds continuously; directly touching the battery pack with flame and burning for 130 seconds continuously. In these extreme tests, the cellular battery has stood up to the test.
Collisions while the vehicle was in motion were one of the causes of the fires, and the battery pack was squeezed and the battery fluid leaked and burned rapidly. JAC's experimenters subjected the battery pack to a maximum squeeze pressure of 200KN, which is equivalent to squeezing the battery system with 20 tons of squeeze pressure, as well as an impact test with an acceleration of 25G. The cellular batteries all performed quite well. In addition, JAC also conducted vibration experiments.
Zhou Peng further emphasized that the biggest feature of the cellular battery is to improve safety, which is expected to reduce the probability of vehicle fire caused by battery failure by an order of magnitude, for example, in the past, 10,000 electric vehicles may have a thermal runaway, after using cellular battery technology will become 100,000 vehicles before one happens.
Each of the three battery technologies has its own characteristics and is used by different companies. The market will give the answer.
