On March 29th, 22, BYD officially released "Blade Battery". At the press conference, Wang Chuanfu, chairman and president of BYD Group, said: "Blade battery embodies BYD's determination to completely end the safety pain point of new energy vehicles, and is more capable of leading the global power battery technology route back to the right path and completely erasing the word" spontaneous combustion "from the dictionary of new energy vehicles. "As an industrial BYD, what are the advantages of blade batteries?
why did the "blade battery" come from
nowadays, the easiest way to improve the vehicle's cruising range is to increase the battery pack or increase the battery capacity density. Among them, the ternary lithium battery, which is widely used, is favored by major car companies because of its advantages in capacity density, but the subsequent safety problems such as spontaneous combustion have also caused headaches for some car companies.
lithium iron phosphate batteries, on the other hand, have always been recognized by the commercial vehicle field for their strong safety, but the energy density has never surpassed that of ternary lithium batteries. Do you have the best of both worlds? Learn about BYD's "blade battery".
Thermal runaway and "needle penetration test"
Although the fire probability of electric vehicles is lower than that of diesel and gasoline engine vehicles, the characteristics of rapid spread and explosion after fire are always chilling. According to the data of the National Big Data Alliance for New Energy Vehicles, vehicles that have had accidents since May 219 are mainly vehicles produced in 218. Among them, 86% of the accident vehicles are ternary lithium-ion batteries. Among them, most of the fire causes are closely related to the thermal runaway of the battery core.
so what is thermal runaway? The thermal runaway of the battery means that the heat generation rate of the chemical reaction inside the battery is much higher than the heat dissipation rate, and a large amount of heat accumulates inside the battery, which leads to the rapid rise of the battery temperature, and finally causes the battery to catch fire or explode. The simplest method to cause thermal runaway of battery pack is short circuit penetrated by acupuncture.
BYD played a video comparing the acupuncture experiments of three kinds of batteries on the day of the conference, responding to the previous questions about the super safety of blade batteries on the Internet. In the video, the steel needle pierces the battery core of the power battery, causing a large area short circuit inside the battery core. Under the same test conditions, the temperature of ternary lithium battery changed dramatically at the moment of acupuncture, and the surface temperature quickly exceeded 5℃, and extreme thermal runaway-violent combustion occurred, and the eggs on the battery surface were blown up.
After being punctured, the traditional massive lithium iron phosphate battery has no open flame and smoke, and the surface temperature reaches 2℃~4℃, and the eggs on the battery surface are burnt at high temperature. BYD's "blade battery" has no open flame and no smoke after penetration, and the surface temperature of the battery is only about 3-6℃. The eggs on the battery surface have not changed and are still in a flowable liquid state.
innovative structure? Breaking through the bottleneck of energy density of lithium iron phosphate batteries
The above picture shows the traditional battery pack structure, which consists of multiple batteries. Because there is no mutual support between batteries, it can only be installed in a battery pack with beams. Although this has a little protection for the battery cell, it inevitably reduces the energy density of the battery pack and increases the overall weight of the battery pack.
the blade battery pack is even simpler. It is just like our usual bending ruler. Although it can be bent by horizontal force, it is difficult to be destroyed by vertical force. At the same time, the cells are arranged in the battery pack in the form of array, thus reducing the use of beams, improving the battery capacity density and reducing the overall quality of the battery pack.
BYD's "blade battery" skipped the "module" through structural innovation, greatly improved the volume utilization rate, and finally achieved the design goal of loading more batteries in the same space. Compared with the traditional modular battery pack, the volume utilization rate of "blade battery" has increased by more than 5%, and the cruising range has reached the same level as that of high-energy ternary lithium battery.
the blade battery still inherits the advantages of lithium iron phosphate battery
in addition to the advantages mentioned above, the blade battery still inherits the advantages of lithium iron phosphate battery, such as many charging times and low loss, which was not mentioned at the press conference, but it is still an indelible aura of lithium iron phosphate battery.
BYD Han is expected to be put into production in June
According to Mr. Wang Chuanfu's on-site disclosure, the first battery equipped with blades is BYD Han EV, which is the flagship car of the "Dynasty Family". Its cruising range under comprehensive working conditions reaches 65 kilometers, and the acceleration of 1 kilometers is 3.9 seconds. The whole vehicle design, especially the interior part, deduces a brand-new family design language, and the car is expected to be put into production and listed in Shenzhen in June this year.
from the focus point of view: for the current consumers of new energy vehicles, apart from policy reasons, the biggest confusion lies in the safety and durability of batteries. After all, spontaneous combustion affects their own safety, and the durability of batteries directly affects their wallets. As the domestic battery boss, BYD has solved the worries of consumers from the technical aspect.
This article comes from the author of Chejia, car home, and does not represent car home's standpoint.