A few days ago, overseas media broke the news that Tesla's gigafactory in Texas, USA, officially put into production a new Model Y. The new car uses the latest die-cast integrated body, and has already used the battery pack technology of the new structure, that is, tesla's first release on battery day in 2020 and the 4680 battery displayed at the German gigafactory open house last year.
Of course, this news has not been officially confirmed by Tesla, but it may not be true. Because Tesla's new technology has always been used in this way, and then gradually disclosed, this practice has caused fans and opponents a headache.
Here Kung Fu Auto will not explore the authenticity of this message with everyone, because there will be no answer in a short period of time. However, Tesla's new battery, how it came about, and how it will change the status quo of the industry, you can talk with you.
The legendary 4680 battery is actually simulated?
Before talking about the 4680 battery, first of all, let's talk about the type of battery. Basically, there are three main ways to package the current power battery, that is, square battery, cylindrical battery and soft pack battery.
As for the proportion of the three, the installed capacity of square batteries in the first three quarters of 2021 is about 69.47GWh, and the installed capacity of cylindrical batteries and soft pack power batteries is 6.63GWh and 6.33GWh, respectively. It can be seen that the square battery is the absolute mainstream, and if the latter two are counted separately, even less than one-tenth of it, which is mainly determined by their different characteristics.
The advantages of the square battery are very obvious, first of all, from the process point of view, it can be both winded and laminated, and it is more convenient to process. Secondly, the structure of the square battery is very simple, and it is easier to achieve customized production. Many of the early electric vehicles were "oil to electricity", and the battery space given was varied, and square batteries were easier to "plug" into. And the square battery is the most convenient to make a battery pack, which can make the battery cell as large as possible, thereby maximizing space saving and energy density.
Therefore, in the early days, most manufacturers have defaulted that the power battery should be square, and there are few other options until Tesla is equipped with a cylindrical battery.
Cylindrical batteries are very familiar to everyone, and they can be seen everywhere in life. In fact, Tesla's cylindrical battery is not much different from the rechargeable battery we use in our daily life, and it is the earliest panasonic 18650 rechargeable battery that is selected. "18" represents 18mm in diameter, 65 for height 65mm, and 0 for cylinder.
Compared with square batteries, the advantages and disadvantages of cylindrical batteries are very obvious. Its core drawback is the large impedance, which makes it work with more heat and more energy loss. It also severely limited its size, because the larger the volume, the greater the impedance, tesla had to install thousands of cylindrical batteries on a car. But its advantages are also very obvious, the biggest advantage is that the "shell ratio" is high, the square battery "shell ratio" is only about 90%, because it must be reserved in all directions to allow it to heat and expand. The cylindrical battery can reach more than 98% because of the force more uniformly dispersed, which allows it to achieve higher energy density.
So although Tesla "foolishly" installed thousands of batteries and equipped with a super-complex BMS battery management system, it is still the first car company to break through 500km endurance.
However, due to the difficulty of battery management, this route is basically only tesla in the line, and it is very difficult. After spending so many years, Tesla's battery has only developed from 1865 to 2170, because the impedance rise caused by the increase in volume is too fatal.
As for the 4860, when Tesla was launched, the industry shook violently, and everyone asked how Tesla made it. Finally, tesla gave the internal answer that the size of the 4860 was simulated by them with software and thought to be close to the limit of the cylindrical battery. This practice is really full of science student romance, I didn't expect that it is really close to mass production now, which is not convinced.
Will the 4680 revolutionize batteries?
Of course, in the eyes of many people, from 1865 to 4680, just turned the No. 5 battery into the No. 2 battery, which is not a black technology, why is the industry so sought after, Rong Kung Fu Car to explain to everyone to know.
First of all, let's do the calculation, assuming that the battery is a perfect cylinder (of course, it is not so perfect in fact), and its volume calculation formula should be V= π *r * h. From 2170 to 4680, its radius and height have increased, and its volume has increased by nearly 5 times. This means that when this new type of battery is grouped, the connection material and control system between the batteries will be greatly reduced, and the volume utilization rate will be further increased.
And as the diameter of the cell body increases, the gap between their arrangement will also increase, which is more advantageous for the heat dissipation line arrangement on the side of the cell. In addition, the output limit of the 4680 battery cell is also stronger, which can theoretically create a faster and more fun vehicle.
Of course, as the volume increases, the battery impedance also increases synchronously, which cannot be solved by simple battery formula optimization, and Tesla's solution is to adopt an innovative "electrodeless ear" design.
The polar ear is a metal conductor derived from the positive and negative collectors, and it is through the pole ear that the current can be connected to the outside of the battery. However, too slender polar ears are not conducive to current conduction, if the current is too large, there will be heat, energy loss increases, and will affect the safety performance.
Tesla's 4680 battery removed the original polar ear and chose to leave a blank at the end of the collector without coating the positive/negative material. Simply put, it is not that there is no polar ear, but the entire end surface has become a polar ear, which greatly reduces the impedance of the battery and solves the heating problem of the cylindrical battery.
The advent of the 4680 battery was revolutionary for Tesla. The first is that the volume utilization rate is improved, after "drying out" a large number of auxiliary materials, it can not only put a larger capacity battery per unit volume, but also reduce the weight. According to Tesla's official statement, its endurance gain is 16%, that is to say, the Model Y rear-drive version that could originally run 545km, upgraded 4680 battery follow-up can reach 632km, this improvement is still quite considerable.
The most critical is the optimization of the production link, and the cumbersome polar ear assembly is simplified by Tesla to laser cutting. And after the increase in volume, it was originally necessary to produce 3,000 batteries, but now only need to produce more than 500 cells. Tesla estimates that a new production line can increase the capacity of the previous production line by 7 times and reduce the cost by 14%.
Based on the fact that the power battery accounts for 30% of the total cost of the electric vehicle, the cost of the Model Y will be reduced by more than 4%. In other words, Model Y will have about 12,000 price reductions. The endurance reached 630km+, and the price was further reduced by more than 10,000, which is almost no opponent in the current market. Or that the original 300,000-level Model Y has no opponents, and now the advantage will only be greater.
In addition, don't forget, Tesla has "previewed" a new car Model Q, the price is equivalent to only about 160,000 yuan. If it is also equipped with a 4680 battery, there will be a very big threat to domestic cars.
Kung Fu shoots
Of course, the size of 4680 is actually simulated by Tesla with software, and it is really hard to believe that this is the only solution. But its spirit of constantly innovating to solve difficulties is very worthy of learning from domestic enterprises. In fact, technology is like this, from one small breakthrough after another, and finally gathering sand into a tower to change our lives.
The new generation of batteries in the BYD and Ningde eras are also already in the making, and how they will pick up Tesla's tricks will wait and see.