The technical dispute between ternary lithium battery and lithium iron phosphate battery has once again become the focus of the industry with the release of BYD blade battery. In March 29, BYD launched a new generation of self-developed lithium iron phosphate battery-“Blade battery”, claiming to overcome the disadvantage of low energy density of traditional lithium iron phosphate battery and change the industry’s dependence on ternary lithium batteries.
Wang Chuanfu, chairman of BYD, also set a Flag at the press conference, saying that he would completely erase “spontaneous combustion” from the dictionary of new energy vehicles.
In addition, the “acupuncture test” on the blade battery is also hot. This reflects to a certain extent, the industry’s curiosity and doubts about the blade battery: how is the blade battery produced? Blade battery really be able to redefine electric vehicle safety standards?
Or in response to doubts, BYD uses facts to speak.
June 4, Verdi battery BYD cloud, the cloud computing arm of independent brand) plant in Chongqing held a factory exploration activities, invited more than a hundred bits media, industry experts to conduct field visits, under the Table blade battery behind the super factory.
Why is BYD obsessed with lithium iron phosphate batteries?
BYD started with batteries in 1995 and succeeded in cross-border in 2003, ranking among automobile manufacturers.
In fact, BYD has been working on the research and development of lithium iron phosphate batteries since 2002. During this period, BYD has also introduced ternary lithium batteries in batches and widely used them in Qin Tang and other dual-mode vehicles.
Even so, in the ternary lithium battery has become the big enterprise pure electric vehicle looting of us as we BYD still did not give up of lithium iron phosphate battery R & D.
BYD blade battery
why is BYD’s obsession with lithium iron phosphate batteries so deep?
Or, why BYD don’t willing to fully overweight has a higher energy density of the ternary lithium battery, choosing instead to secure but low energy density of the lithium iron phosphate battery?
Judging from the material composition and chemical structure, lithium iron phosphate battery has incomparable safety advantages over ternary lithium batteries.
The cathode materials of ternary lithium batteries are mainly nickel-cobalt-manganese and nickel-cobalt-aluminum, among which manganese or aluminum is easy to decompose under the condition of too high temperature and reacts violently with oxygen.
“In the 500 ℃ temperature of lithium iron phosphate materials and structures are very stable, but the ternary lithium at 200 ℃ or so will be decomposed, and the chemical reaction of more intensive released oxygen molecules, it is more likely to cause heat out of control.” Sun Huajun, deputy general manager of Fudi battery company, said.
But as a result of the energy density is less than the ternary lithium plus subsidies for new energy vehicles on the car of long life has, which also leads to the past few years, the market of the most with lithium iron phosphate battery has been cut away from, pass.
However, BYD has always believed that the battery of the issue of security is crucial.
Therefore, BYD has been on the lithium iron phosphate battery is the physical structure of the tune, lithium iron phosphate battery safety characteristics, at the same time, the system energy density to improve.
In the past 18 years, BYD has increased its battery capacity by 70% under the same volume. At the same time of CIGS thin film solar cell has also undergone a great change, the conventional battery internal waste of space utilization, cell of aspect ratio increased from 3.8 to 10.6.
Based on various optimization designs, today’s blade battery Super package is available.
“In the end the goal is (battery energy density of as well as a reduction in the cost of at the same time, security performance to the ultimate.” Verdi battery factory, deputy general manager of the Sun arms concludes: “blade battery” in the produce of the middle and late Tang dynasty was not accidental inspiration nor whim’s whimsical products is in speeding up our production rates in the last years, the inevitable products brought by the long-term deep cultivation in the field of power batteries.”
insert the battery is how to make?
At present, is located in the Chongqing Bishan area of Verdi battery factory is a blade battery only the production base of plants with a total investment of 10 billion billion yuan, planning with an annual production capacity of their 20GWH.
From February 2019 start to March 2020 blade battery officially launched, blade battery factory with only 1 year time becomes highly lean, automation, manufacturing information management system of the super factory.
The battery production line and production equipment of the whole factory have been highly automated and mechanized. The most important thing is, the further understanding of the blade how batteries production processing out of.
In production until the battery blade battery production environment has a very stringent requirements, such as the workshop of a non-dusting granulate, 26 degrees Celsius of the constant temperature control, and 1% or less of the humidity control.
Sun Huajun said that in order to minimize the short circuit of the battery, they came up with a dust classification management concept of in a number of key production process, can one cubic meter of space, the particles of 5 microns (1/20 thickness of hair) are not more than 29, which meets the same standard as that of LCD production workshop.
During the visit to the factory, according to the engineer of the battery, the production of the blade battery experienced eight production processes of batching, coating, rolling, laminating, assembly, baking, liquid injection and testing.
For example, in the batching process, the precision of the batching system needs to be controlled at 2‰ to ensure the stability of the slurry; The water of the batching needs to be filtered, in the finally obtained high purity water, there are no impurity ions except hydrogen ions and hydroxide ions separated by water molecules.
In the coating process, the slurry is required to be quickly, widely, uniformly and accurately coated on the surface of the current collector. That is, two-sided simultaneous coating, coating maximum width up to 1300mm per unit area of coating weight deviation is less than 1%.
Rolling link with high-precision roll electrode pads according to a preset thickness of rolled requirements 1200mm large width of the rolling speed of up to 120 m/min, thickness control 2μm within ensure width pole piece thickness uniformity.
The lamination link is the moment to test the battery production process. It is necessary to laminate the pole pieces with a length of nearly 0.3, with the tolerance controlled within 0.3mm and the accuracy and speed of the monolithic lamination efficiency within s/pcs.
Blade battery assembly process
compared with the traditional roll-to-roll production process lamination process of the efficiency will be lower. But Sun Huajun said in an interview that Currently blade battery of the laminations level is 0.3 seconds, may have just put into production remains to be implemented but 0.3 seconds/sheet should be able to obtain, with the traditional winding process compared to the cost of little difference.
The laminations after by an insulating, welding, into the shell, sealing and other processes are assembled into a cell; And then through the vacuum negative pressure and the tank pressure mode, an electrolytic solution is fully injected into the cell and quickly complete the assimilation; finally, to complete the battery detection.
Insert the battery pack process schematic
in addition, Sun Huajun also said that in order to realize the automatic digitalization of battery production, each battery has an ID two-dimensional code, which can be traced back to every production equipment, time point and raw material it passes through, from raw materials traced back to the battery products to achieve forward reverse full traceability.
Insert the battery set a new benchmark for?
Then, subjected to many harsh production line out of the blade battery, have what kind of performance?
In the Super factories, Lei Feng new yesway have the opportunity to have a close look of the battery sting test “. Sting test “is the essence of the simulated extreme case inside the battery short-circuit test method to verify the safety of the battery.
When the steel acupuncture to use PIN provides a battery internal short-circuiting of the pathway, the battery of the electrical energy is transformed into heat, resulting in short time energy of the outbreak and release, it is possible to produce smoke, leakage, even a fire and explosion. This is also the main reason why most electric vehicles burn.
According to Verdi battery Engineer: “nail penetration test” in the battery is fully charged, having a diameter of 5mm steel needle, 25mm per second speed of vertical puncture ternary lithium blade battery cell, and then allowed to stand for one hour.
It can be clearly seen that when the ternary lithium battery core was pierced by the steel needle, the battery core expanded rapidly and exploded with the naked eye, and the fire tongue appeared crazily from the inside. While the blade of the battery performance is a smoke-free, no fire, no explosion.
The successful adoption of the “nail penetration test, just insert battery safety performance.
Generally, BYD from an internal short circuit, external short circuit, overcharge, collision, high pressure, connection, hazardous gases seven security dimensions, electrical safety, safety of machinery, thermal safety, environmental reliability, gas flammability 5 aspects of safety evaluation, from monomer, a module, a battery pack system, 4 levels all-round building of power battery Super security system.
In the battery pack in terms of the strength of the long 96cm, width 9cm, height 1.35cm of the unit cells, through the array of the arranged together, it is inserted into the battery pack like a “blade” to form a structure similar to the honeycomb aluminum plate. Because the battery to module and liang hua structure greatly improves the battery pack of the strength to the point where it became a rigid whole. It is understood that the blade battery can withstand 80Hz vibration intensity, 60g crash acceleration, 800kN crush strengths of and 445kN of compressive strength.
At present, equipped with a blade of the battery BYD “Han can achieve 600km of life. Sun arms also said that in the future through the material of the innovation and upgrading, life can reach 700 to 800km. “Because the blade battery which is capable of significantly reducing the ternary lithium battery safety and strength is not enough to increase the structure, so as to reduce the weight of the vehicle, so our monomers energy density than the ternary lithium high, but can reach the mainstream ternary lithium battery equivalent of life.” Sun arms explained.
as for the concern for the industry low temperature on the blade battery also has a good performance. Sun Huajun said low-temperature and high-power charging power blade battery is higher than the three-dimensional battery. While the low temperature low power of the charging power blade battery is lower than the three-dimensional battery but can meet demand. Blade low temperature discharge capacity can be maintained at 90% of the low temperature of the discharge power blade battery still better than that of the three-dimensional battery.
In terms of service life, the storage life and cycle life of the blade battery are better than that of the ternary lithium battery, which can guarantee the use for a long period of 8 years or even longer, 500,000 kilometers or even 1 million kilometers.
In addition, the blade battery 33 minutes electricity from 10% is filled to 80%, support Chinese 3.9 seconds hundred kilometers acceleration, the instantaneous maximum power up to 363kW, about 500 horsepower.
By virtue of the blade of the battery six performance blade battery is very likely to power battery industry has brought a revolution in the energy density and safety of both.
The power battery of the future
at this point, the emergence of blade batteries may make lithium iron phosphate batteries the “darling” of the industry again “.
But just as the battery industry said: The Development of generation, reserve generation application generation. Power Battery Industry R & D and the contention for the discourse does not rest.
The personage inside course of study, since the blade of the battery without liang hua and de-module structure can bring great security, if the ternary lithium battery made blade battery, the battery will more progress has been made?
This sun arms responded: “blade battery structure innovation, other material systems is also possible (with this three-tier approach) instead of our answer is possible, but the core depends on the entire electric vehicle of the market for the range of needs. Because ternary battery and lithium iron phosphate have their own advantages and disadvantages, the volume energy density of ternary battery made into “blade battery” may be higher.” The energy density of the to improvement in a much better position to ease market of mileage anxiety.
In terms of material innovation of batteries, solid-state batteries and ternary lithium batteries without cobalt (or high nickel and low cobalt) are also expected by the industry.
But Sun Huajun said the former currently is stuck in the research level, the future is a development direction, but it might not be 10 or so; With regard to the latter cobalt-free-battery, there is also the possibility of low cobalt content leading to unstable battery material structure, and there is no real product performance at present.
It is worth mentioning that Tesla Musk’s “battery Day” also has rumors that batteries are cobalt-free. Zeng Yuqun, chairman of Ningde times, also revealed that the company has its own “Cobalt-free” Battery technology reserve and is currently progressing smoothly in research and development.
It can be seen that in the arms race of power batteries, each family is still secretly competing. However, before the disruptive revolution brought by the innovation of battery materials, BYD’s blade battery may be re-named lithium iron phosphate battery and lead the new outlet of power battery.