Recently, BYD has become the focus of public opinion for three reasons:
1. At the 100-person meeting two days ago, BYD Chairman Wang Chuanfu revealed some information about "blade batteries". "The information: "It will be mass-produced for the first time in the Chongqing factory in March this year. The newly launched "Blade Battery" has a volume specific energy density that is 50% higher than that of traditional iron batteries. It has the characteristics of high safety and long life. The vehicle life can reach more than one million kilometers. The first model equipped with the "Blade Battery" will be BYD's "Han", which will be launched in June this year and has a range of 600 kilometers. "
2. Also at the 100-person meeting, Shu Youxing, general manager of BYD's International Cooperation Division, revealed: BYD has more than 300 "core technologies" for this "blade battery".
3. In the following days, BYD's stock rose sharply due to the good news about blade batteries.
Why is this battery technology attracting so much attention? In fact, in the final analysis, it is because the "weight" of the battery in a pure electric vehicle is very heavy. This portion is not just about weight, but also cost. The battery cost accounts for 1/3-1/2 of the total vehicle cost. This is also one of the reasons why EVs have not become popular on a large scale - it is difficult to significantly reduce the cost of the entire vehicle, resulting in high selling prices, which naturally cannot compete with traditional fuel vehicles.
As for the blade battery technology, BYD believes that it is possible to reduce battery costs on a large scale, which is undoubtedly a huge benefit to them and can also improve product competitiveness to a certain extent. The surge in BYD's stock may also be because the capital market has seen the potential "value" behind blade battery technology.
Then the question is, is blade battery technology really that powerful? How does it perform? In this article, we provide some interpretation of the “blade battery” technology based on the information currently available.
What is "Blade Battery"?
BYD’s “blade battery” technology can be found in the following patent applications at the National Patent Office:
BYD’s battery patent is a patent for battery pack design. In this battery pack, a long single cell design is innovatively used to integrate multiple long single cells into a battery array, thereby increasing the capacity of the battery pack. At the same time, the single cells have their own specific sizes. itself to improve the overall stiffness of the battery pack.
Specifically, BYD has improved the battery cells. Because the battery cells look like blades, they are named "blade batteries", which can allow more battery cells to be placed in the battery pack. At the same time, because the use of cross beams or longitudinal beams in the battery pack is reduced or even eliminated, the space utilization of the battery pack is improved, thereby improving the capacity, voltage and endurance of the entire battery pack.
What is the specific effect? BYD gave an example in its patent: In electric vehicles, this design can increase the space utilization rate from about 40% to more than 60% or even higher, such as 80%.
At the same time, because fewer beams and longitudinal beams are used, the manufacturing process of the battery pack is simplified, the assembly complexity of single cells is reduced, and the production cost is reduced; on the other hand, it can also Reduce the weight of the battery pack to a certain extent. ?Electric vehicles using this kind of battery pack can theoretically achieve lighter weight and improved endurance. In addition, because the single battery has a hard shell (aluminum shell or steel shell) and is very long, the structural strength of the battery pack can be ensured directly by the single battery itself instead of the reinforced structure, ensuring that the battery pack is not easily exposed to external forces. Deformation occurs.
Previously, our power battery pack packaging was divided into three parts: battery cell - battery module - battery pack. That is: packaging the single battery into a battery module, and then packaging the battery module into a battery pack, which is what we often call a "battery pack." According to the previous explanation given by Ouyang Minggao, BYD's "blade battery" actually removes the intermediate links and directly assembles the battery cells into a battery pack. "How wide the car is, the battery can be as wide as possible. The previous battery was very short, but now the strip is like a blade, but the height is still so high. The cooling air ducts, explosion-proof valves and other configurations are placed on both sides, and then Long batteries stacked one by one have very good stiffness and strength, and can also be used as structural parts. This is an important innovation that will further reduce the cost of manufacturing single cells.
” Ouyang Minggao praised this technology very much.
For lithium iron phosphate batteries, what matters is not the weight-to-energy ratio, but the volume-to-energy ratio. The volume specific energy is relatively small because the material is compacted and sealed. BYD's blade battery can solve this problem very well. According to information disclosed by relevant sources: "The volume specific energy density of the new battery is increased by about 50%, and the cost is estimated to be reduced by 20%-30%." Wang Chuanfu said that the "Blade Battery" will first be installed on BYD's "Han", with a cruising range of 600 kilometers (should be NEDC operating conditions). From this point of view, this blade battery technology is indeed promising.
The above is everything we know about "blade batteries".
Why does BYD use recycled iron batteries?
BYD’s blade batteries will use lithium iron phosphate batteries.
Why is this?
At present, there are two main types of lithium-ion batteries used in passenger car power batteries: one is lithium iron phosphate battery and the other is ternary lithium battery. Driven by subsidy policies, mainstream manufacturers currently use ternary lithium batteries. The advantages of lithium iron phosphate batteries are that they have many cycles, high safety, and are relatively stable; the disadvantage is that the specific energy of the battery is low, which is why everyone subsequently switched to the ternary lithium battery route, because the ternary lithium battery has a high specific energy and is easier to use. Meet the national subsidy policy. The reduction of subsidies will make policy factors have less and less impact on the development route of battery technology.
After subsidies are withdrawn, how to choose the appropriate battery technology route? BYD gave its own answer: "Returning to the old business (reusing lithium iron phosphate batteries)" is the direction they are considering.
In addition, although the energy density of lithium iron phosphate batteries is relatively low, the specific energy ceiling of iron batteries is very low, and it is easy to enter a bottleneck. This is also related to the current lithium-ion battery material system. At this time, there is a balance to be made: safety? or? cost. If you want to increase the specific energy of a single cell, the safety of the battery cannot be guaranteed (spontaneous combustion will occur), and a lot of things (such as battery management systems) need to be added to maintain the consistency of the battery, which are all costs.
Ouyang Minggao said that in 2019, the cost of power batteries in China has reached 0.6 yuan-1 yuan/Wh, among which lithium iron phosphate batteries can reach 0.6 yuan/Wh, that is, It is said that the cost of lithium iron phosphate batteries can be less than US$100/kWh, and this target value is regarded by many as the watershed for whether electric vehicles can compete with fuel vehicles. This is definitely one of the reasons why BYD wants to use lithium iron phosphate batteries back; in addition, compared to ternary lithium batteries, BYD has a deeper accumulation in the field of lithium iron phosphate batteries, so making technological breakthroughs from this point is also Within reason.
Generally speaking, BYD's "Blade Battery" is not a technical innovation in the battery cell itself, but more of an innovation in the battery pack. The information officially disclosed by BYD also confirms this. At the same time, the official said that the battery itself will also have certain improvements: "The energy density increase of the blade battery not only comes from the optimization of the size of the battery and the pack, but also the battery Innovations in core and internal design and production processes?"
To?be?Continue...
But the matter is not over. There are still many questions about the blade battery: it What are the specific improvements in battery cells? What is the final performance (such as discharge capacity, attenuation)? And most importantly, what impact will it have on BYD's own open battery business?
In March this year, the "Blade Batteries" will be mass-produced for the first time at BYD's Chongqing factory. By then, the truth will be revealed.
This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.