■ let's tie it first!
before the official visit to the factory, BYD decided to make a big move first-not accepting it! What participated in the acupuncture experiment this time was a ternary lithium battery and blade battery produced by BYD.
as can be seen from the picture, after the ternary lithium battery was punctured, the voltage dropped to zero in almost one second (that is, a short circuit occurred), and then smoke caught fire and made a loud noise.
The picture shows the puncture experimental image of ternary lithium battery. The red line represents the voltage, the green line represents the safety valve temperature, and the yellow line represents the puncture point temperature
. After 2 minutes of puncture, the voltage of the blade battery only drops at a very slow speed, and there is no smoke and fire. The contrast is still very obvious.
I have written two articles about BYD and Contemporary Amperex Technology Co., Limited before, and found that many netizens questioned whether the voltage of the blade battery dropped to zero after puncture, and there were two kinds of acupuncture experiment videos of the blade battery circulating on the Internet, so I will show you the truth this time.
Looking at this experiment alone, BYD's blade battery did not drop to zero after 2 minutes of puncture. I asked the field engineer, and he said that they had left the punctured battery for one day, and the voltage did not drop to zero.
the initial voltage of the experiment is 3.42 volts, the starting time is about 1:47, and the picture is 1:57, in which 1-1-1 is the real-time voltage, 1-1-2 is the temperature of the safety valve, and 1-2-3 is the temperature of the acupuncture point.
■ can the blade battery suppress internal short circuit?
so why is this? BYD's engineers said that after puncture, there were many short circuits inside the battery, and they suppressed the severe short circuit inside the battery through structural design.
then I asked, since it is "structural design", not the characteristics of the material itself, can this technology be applied to ternary lithium batteries?
The engineers said that they are doing research in this field at present. So maybe we can expect BYD to develop a safer ternary lithium battery?
After watching the exciting acupuncture experiment, let's talk about some issues that everyone cares about.
■ BYD has not neglected system security!
In the previous incident of Contemporary Amperex Technology Co., Limited and BYD, Contemporary Amperex Technology Co., Limited "insinuated" that BYD equated the passing of abuse test with battery safety, which made BYD seem to be obsessed with battery safety and ignored system safety. In fact, BYD is also very concerned about the safety of the whole system. They guarantee the safety of blade batteries from seven dimensions, four levels and five aspects. In addition to acupuncture, BYD is also equipped with corresponding safety measures in the dimensions of overcharge and collision.
For example, everyone is concerned about overcharging. According to BYD's data, when the blade battery is charged 2.6 times higher than the maximum voltage, it only smokes, but does not catch fire or explode.
when a battery cell is out of thermal control, the adjacent battery will not catch fire or explode, and the whole battery pack will not catch fire due to chain reaction.
In this extreme working condition, it can only smoke without fire, which means that there will be no safety problems in daily use with mild working conditions. To take a step back, even if the heat is out of control, the model equipped with blade battery can provide enough escape and rescue time.
■ poor low temperature performance? It doesn't exist!
We all know that lithium batteries are not frost-resistant, especially in Ferrous lithium phosphate, where low-temperature performance is often criticized due to congenital problems. Even Li Xiang, CEO of LI, once questioned the low-temperature performance of blade batteries in Weibo.
BYD gives the measured data, which shows that the discharge capacity of the blade battery is still maintained at 9% at MINUS 2 degrees Celsius. However, in the case of low temperature and low SOC, it performs better than lithium ternary.
BYD also gives data about the low-temperature charging ability of blade batteries. The data shows that the low-temperature charging time of blade batteries is no different from that of ternary lithium batteries, but it lags behind in the low-temperature charging power.
These data also confirm the words of Mr. Li Yunfei, the deputy general manager of BYD's sales: "We dare not sell it even if the low temperature performance is not good.".
however, before we get a real car for winter testing, we can't conclude that the blade battery is really not afraid of low temperature just based on BYD's data. I prefer to trust the evaluation by the third party and the media, and please look forward to the follow-up winter measurement of the electric state.
■ Get to know Chongqing Fudi Factory quickly
This factory has invested 1 billion yuan for the production project of batteries and supporting materials, covering an area of about 1,5 mu, with a total construction area of about 95, square meters. It has built a new production workshop, purchased 958 sets of related equipment, and built 8 lithium-ion battery production lines. After the project is completed, the production capacity of lithium-ion batteries is 2 billion yuan, with an annual output value of 2 billion yuan.
The factory started construction in February, 219, and the blade battery was officially launched in March, 22. It took only one year to have a lean, automated and information-based manufacturing management system, as well as a blade battery production line and production equipment independently developed by BYD, and a number of highly confidential core technologies.
■ How is the blade battery produced?
finally, how the blade battery was produced. In fact, the blade battery is also a power battery in essence, so its manufacturing process is similar to that of ordinary batteries, and it is completed through batching, coating, rolling and laminating.
firstly, the active substance, nano conductive material, solvent and binder are automatically mixed according to a preset ratio to form uniform and stable electrode slurry.
the next step is coating, that is, coating the slurry on the copper foil to ensure that no particles, sundries, dust, etc. are mixed into the pole piece. The machine used looks like a loom.
while rolling is to use a roller to compact the coated electrode sheet according to the preset thickness, so as to obtain the preset thickness and bulk density of the electrode sheet.
Then there is lamination. The length of the pole piece of the blade battery is nearly one meter, and BYD's original lamination process can control the alignment tolerance within .3mm, and the lamination speed reaches the highest level in the industry-.3s/piece.
then, the machine will automatically convey the structural parts and realize accurate positioning, and assemble them into batteries through insulation, welding, casing, sealing and other processes. After baking to remove water, adding electrolyte and testing, the blade battery core is completed.
finally, each battery cell will form a battery pack. BYD's CTP technology (batteries directly go to the battery pack without modules) can improve the volume utilization rate of the battery pack and help to improve the energy density.
The following figure shows the advantages of CTP technology:
BYD claims that the blade battery can reduce the structural parts added by ternary lithium batteries due to insufficient battery safety and strength, thus reducing the vehicle weight, so the energy density of the single battery is not as high as that of ternary lithium batteries, but it can also reach the same endurance of mainstream ternary lithium batteries. For example, BYD Han EV has a comprehensive cruising range of 65 kilometers.
Recently, there is a hot word called "Industry 4.". You can simply understand it as intelligent factory, intelligent production and intelligent logistics. Chongqing Fudi Factory is also a practitioner of Industry 4.. Besides high precision and automation, digital construction is not backward. Every blade battery product has an exclusive' ID card'. In the future, the data of the product during use will also provide important reference for BYD to continuously improve its technology and improve its products.
■ State Comments
Sun Huajun, deputy general manager of Foday Battery Company, said, "Today, almost all automobile brands you can think of are discussing cooperation schemes based on blade battery technology with us". This shows BYD's ambition and strength. We know that the world's auto giants, such as Volkswagen and Tesla, want to take the production and research and development of batteries into their own hands. BYD has obviously done this first, and has begun to sell batteries to the outside world, which gives BYD a lot of advantages in competing with domestic and foreign rivals.
finally, I'm very much looking forward to the test drive of Han EV equipped with blade battery earlier, and see what surprises this battery can give us with BYD's flagship model. Please also look forward to the follow-up report of the electric state.
This article comes from the author of Chejia, car home, and does not represent car home's standpoint.