Author?|?Wang?hui
Source?|?Auto Grand View
In a video, BYD fried three eggs and one was blown away. One egg was burnt, but the surface of the other egg was unchanged.
This is March 29, BYD's "Blade Battery" press conference, the pledge to compare the acupuncture test of three types of batteries was played in response to previous concerns on the Internet about the superior safety of blade batteries. question.
The safety of electric vehicles depends largely on the safety of the battery. When an electric vehicle encounters a collision, battery short circuit, or puncture by a sharp object, it is easy to induce thermal runaway of the battery, which may lead to vehicle fires, explosions and other safety accidents.
In the past few years, due to the relatively low energy density, lithium iron phosphate batteries have been replaced by third-generation batteries with higher energy density but poor thermal stability in the competition of new energy passenger vehicle manufacturers to pursue cruising range. Lithium-ion batteries are left behind. Due to better cruising range, ternary lithium batteries have gradually become the mainstream of new energy passenger vehicles, while lithium iron phosphate batteries are more used in commercial vehicles.
However, Tesla, which carries a ternary battery, became well known after the Shanghai basement burning incident last year. Before that, in 2017, an electric car of the Croatian supercar brand Rimac overturned. The fire lasted for five days, which was shocking.
In addition, there are many cases of spontaneous combustion of electric vehicles in China. The safety caused by these spontaneous combustion incidents has become a major weakness of electric vehicles in pleasing consumers.
"Blade battery" is the latest generation of lithium iron phosphate battery developed by BYD. BYD said that the "blade battery" has safety that other power batteries cannot match, and has both long life and long endurance. Its birth has redefined the safety standards of new energy vehicles and led the world to a new level of power battery safety.
Wang Chuanfu, Chairman and President of BYD Group, said: "The 'Blade Battery' reflects BYD's determination to completely end the safety pain points of new energy vehicles, and is more capable of leading the global power battery technology route back to the right path and putting ' The word "spontaneous combustion" has been completely erased from the dictionary of new energy vehicles."
Wang Chuanfu's endorsement is full of confidence that the "blade battery" can really get rid of the "thermal runaway" that may occur in traditional power batteries. "Nightmare?" ?
Acupuncture and fried eggs
In fact, since the news that BYD developed a blade battery last year, it has triggered heated discussions in the industry.
Currently, in the new energy passenger vehicle market, most batteries use ternary lithium batteries, while the market share of lithium iron phosphate batteries continues to decline.
“Blade batteries will change the industry’s reliance on ternary batteries, return the technical route of power batteries to the right path, and redefine the safety standards of new energy vehicles.” Wang Chuanfu said.
At the press conference, BYD did not introduce too much about the technical details and performance parameters of the blade battery. Instead, it used a "needle-pricking-fried-egg" method to show everyone how safe the blade battery is.
"Acupuncture penetration testing" is recognized in the industry as the most stringent testing method for the safety of battery cells. This test requires using a steel needle to pierce the power battery cell, causing a large area short circuit inside the cell.
Under the same test conditions, the ternary lithium battery experienced drastic temperature changes at the moment of acupuncture. The surface temperature quickly exceeded 500°C, and extreme thermal runaway occurred - a violent combustion phenomenon. The surface of the battery The egg was blown away; the traditional block lithium iron phosphate battery had no open flame and smoke after being punctured, and the surface temperature reached 200℃-400℃, and the eggs on the surface of the battery were scorched by the high temperature; BYD's "blade battery" after being penetrated There is no open flame and no smoke. The temperature on the surface of the battery is only about 30-60°C. The eggs on the surface of the battery have not changed and are still in a flowable liquid state.
Why use acupuncture battery testing? Try our best to improve the safety of electric vehicles under the current technical conditions.
Passive measures are to improve the stability of battery cells, increase monitoring measures, etc., to prevent internal problems from spontaneous combustion; active measures are to bump the battery pack into a solid shell, separate the cells in modules, etc., to prevent or Prevent the battery from exploding after an accident.
In fact, BYD used acupuncture to prick the battery this time to simulate what might happen to electric vehicle batteries after an accident. When the steel needle penetrates into the battery, it will cause the battery to short-circuit and generate abnormally high temperatures. If the heat cannot be dissipated in time, it may cause combustion and explosion.
As for the performance of BYD's blade batteries in acupuncture experiments, Ouyang Minggao, an academician of the Chinese Academy of Sciences, analyzed and pointed out that the design of the blade battery makes it produce less heat and dissipate heat quickly during short circuit, and evaluated the performance of the blade battery as "very Excellent". Is it safe without fear of puncture?
“Almost all car brands you can think of are discussing cooperation plans with us based on blade battery technology.” He Long, vice president of BYD Group and chairman of Fudi Battery, said that BYD’s “Fudi series "All core technologies and components will be open to the entire new energy vehicle industry to benefit the industry and consumers.
It is understood that BYD blade batteries have entered the mass production stage.
Wang Chuanfu also revealed at the meeting that the "blade battery" is only available in BYD Han pure electric models, and there are no plans for other models. As the flagship sedan that leads the "Dynasty Family", BYD Han EV has a cruising range of 605 kilometers under comprehensive operating conditions and can accelerate from 0 to 100 kilometers in 3.9 seconds. It was put into production in Shenzhen in June this year.
In fact, by joining hands with Daimler and Toyota, BYD’s global cooperation in electrification has already begun. The launch of the "Blade Battery" is BYD's hope to consolidate and expand its technological advantages in the field of pure electric vehicles.
At the press conference, Wang Chuanfu also elaborated on BYD’s battery development direction: “First, we must ensure safety; secondly, we must have long battery life and long life; thirdly, we must reduce dependence on rare metals. "
Blade battery does not actually refer to chemical materials, but to a BYD patented battery cell shape, which is long and flat like a blade. The reason why BYD invented such a special shape battery is to make up for the shortcomings of lithium iron phosphate and at the same time take advantage of the advantages of lithium iron phosphate to fight against the ternary lithium camp.
According to BYD, through structural innovation, the "blade battery" can skip the "module" when forming a group, which greatly improves the volume utilization and ultimately allows more cells to be installed in the same space. design goals. Compared with traditional modular battery packs, the volume utilization of "blade batteries" has increased by more than 50%, and the cruising range has reached the same level as high-energy ternary lithium batteries.
While greatly improving the mass energy density and volume energy density of the system, the complexity of the battery system has been greatly reduced due to the removal of the intermediate structure of the "module", which has also brought about more High product stability and lower failure rate.
In terms of safety, blade batteries with lithium iron phosphate formula are not afraid of being "pricked". First, because of its thin sheet shape, the degree of short circuit after the steel needle is inserted is smaller and the abnormal heat generated is smaller. Less, and at the same time it has a larger heat dissipation area; secondly, because the lithium iron phosphate formula is inherently more stable than ternary lithium.
In fact, it is not just acupuncture tests. In order to prove the reliability of their products, many electric vehicle brands and battery manufacturers like to give audiences fire, impact, water immersion and other experiments. Blade batteries are not afraid of being punctured. Is it safe enough?
I'm afraid it's not that simple. It's also a needle prick. In a given standard "ravage" experiment, the impact in a real accident is more cruel than in the experiment. Whether the blade battery can withstand the test? It needs to be tested in harsh real-life scenarios.
However, BYD is not alone in leading the way. Tesla is also discussing with CATL to turn to lithium iron phosphate in the research and development of next-generation batteries.
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.