A new energy vehicle with a battery pack as a chassis Do you dare to buy it?

(Wen/He Zhonggang) After the new car-making forces have undergone round after round of reshuffle, zero-run cars have become a unique existence. It is not like "Wei Xiaoli" is often exposed to the spotlight, nor is it like the future and the horse has a brief glory and then falls silent. From the first S01 positioning electric coupe into the market, to the latest C11 into the mainstream market segment, zero running has always been developing in a more pragmatic posture in Wuzi.

Compared with the new front-line car-making forces around the halo, the starting point of zero running is not high, but the origin is not ordinary. Its founding team comes from security giant Dahua Shares. Zhu Jiangming, the founder of Zero Run, was the co-founder and CTO of Dahua Co., Ltd. He is a typical technical controller, although Zhu Jiangming is not as well-known as other founders on the road of zero-run development, he is also the man who once made a bold statement that "surpasses Tesla in three years".

Zhu Jiangming has set a clear development direction for zero running, and the low-key zero running has become the only emerging electric vehicle company in China that has independently developed.

On April 25, 2022, Zero Run Technology officially released its latest research and development achievements--- CTC battery chassis integration technology. Zhu Jiangming, founder of Zero Run, said that the integrated technology of CTC battery chassis will be free and open to share, so that consumers can enjoy the dividends brought by technological progress.

So, the question is, is the CTC battery chassis integration technology proposed by Zero Run reliable?

First of all, we need to understand what is CTC battery chassis integration technology? Taken literally, CTC is the meaning of Cell to Chasis, that is, battery chassis integration. This concept is not original, in fact, as early as the advent of the new energy era, traditional car companies have proposed the concept and launched conceptual products.

However, the first time CTC technology has come to the stage is Tesla, which has the title of leader in the new energy army. In 2020, Elon Musk first interpreted CTC technology at Tesla Battery Day. In the mouths of "Iron Man of Silicon Valley," CTC technology is like an airplane using its wings as a fuel tank, and on an electric car, "there is no need to put another box in the box." ”

Anyone familiar with Musk knows that the bull he has bragged about always has a time to land. Tesla's own CTC technology will be officially applied in the Texas Gigafactory in 2022.

As the first place in the global power battery assembly volume for consecutive years, the Ningde era has also aimed at the integration of CTC battery chassis. Zeng Yuqun, chairman of CATL, once said at the China Automotive Blue Book Forum that CATL is accelerating the mass production process of CTC technology and is expected to be put into mass production in 2024.

CTC technology, which is favored by the global sales brand of new energy vehicles and the top spot in the total assembly volume of power batteries, is naturally also a fragrant feast for other companies to compete. However, according to the information released by Zero Run, they are indeed the Chinese companies with the highest mass production process.

How many stages of development has the power battery structure gone through?

CTC technology is a major upgrade of the power battery structure, in the early stage of the development of new energy vehicles, car companies are independent, all vehicle products are based on the fuel vehicle architecture for transformation, power batteries can only see the seams and needles for layout.

This practice is inefficient, the battery pack has a peculiar shape, can not adapt to the flexible production method, and the cost is extremely high. This led to the chaos of the initial development of new energy vehicles "group of demons dancing".

VDA standard module

After a period of exploration, the automotive industry realized that only a unified battery standard is conducive to the healthy growth of the industry. In 2015, the German Federation of Automotive Industries issued the VDA standard size and structural requirements for power batteries, which were recognized by car companies. As a result, the development of power batteries has officially entered the 1.0 era.

The VDA standard module first integrates the battery cell into a module, the module then forms a battery pack, and finally the battery pack is placed in the chassis of the vehicle. After three rounds of combination, it became the effect of the box inside Musk's mouth.

The advantage of the VDA standard module is that the power battery manufacturing standard is unified, which is convenient for large-scale promotion. However, the disadvantage is that the manufacturing difficulty is increased, the structure is complex, and the reliability is affected. What makes car companies most unacceptable is that due to the "box set box", the number of battery cell arrangements is reduced, which seriously affects the vehicle endurance in the era of low battery energy density.

CTP large module

In order to solve the inherent problems of VDA standard modules, the automotive industry began to explore new battery pack structures. A simple solution is to reduce the occupation of chassis space by the cell package structure, so that the battery cell directly crosses the module stage and directly forms the battery pack.

This structure is known in the industry as Cell To Pack, which is the CTP large module. After changing the battery pack structure, a larger number of cells can be arranged in the unit size, making the vehicle's endurance performance better than that of products that apply VDA standard modules. In addition, due to the reduction of the structure, the performance of the new battery pack in terms of manufacturing convenience and reliability has been improved.

At a time when the track of new energy vehicles is becoming more and more crowded and the competition is becoming more and more fierce, car companies have paid unprecedented attention to the performance indicators of vehicle endurance. In order to push the product performance to a new level, everyone's attention has once again focused on improving the battery pack structure, which is the background of the birth of CTC technology.

What are the advantages and disadvantages of CTC battery chassis integration technology?

Since it has become the consensus of the industry to reduce the burden on the battery pack, the new technology naturally continues this concept. In the era of CTP large modules, the battery pack housing needs to be strong enough to protect the internal cells. Although there are already new energy vehicle products developed based on pure electric vehicle platforms at this time, CTP battery packs still bring two major problems.

One is the encroachment of the battery pack on the chassis space, which leads to the new energy vehicles we see based on pure electric platforms being larger than the same level of fuel vehicles in terms of body size. On the one hand, this is to discharge more batteries and improve the endurance; on the other hand, it is a compromise to ensure the space for the occupants in the car.

The second problem is that the weight of the battery pack is too high, which leads to the chassis tuning of the new energy vehicle equipped with such battery packs is nerve-wracking, and a little carelessness will bring disastrous vehicle dynamic performance.

Therefore, removing the shell of the battery pack has become an urgent thing, and CTC technology is the best solution. In short, CTC technology eliminates the previous concept of modules and battery packs, directly places the battery cells on the chassis of the vehicle, and through structural optimization, makes it have better performance and lower manufacturing costs than CTP large module battery packs.

According to the information officially revealed by Zero Run, the CTC battery chassis integration technology used can reduce the number of parts by 20%, reduce the cost of structural parts by 15%, and increase the space by 14.5%. The vertical space of the crew compartment has also been increased by 10 mm, which can allow the zero-run follow-up new car to provide a better riding experience for the occupants of the car while maintaining a beautiful proportion.

Of course, CTC technology is not perfect, and there are still some obvious problems in itself. First, the highly integrated design leads to poor serviceability. If the battery cell is damaged, it is difficult to replace the module alone or the inexpensive solution of the battery cell. At the same time, the battery pack with the high degree of integration with the vehicle chassis also makes it difficult to implement the power replacement route.

Since the housing to house the cells and modules is eliminated, battery packs using CTC technology require higher requirements for structural safety and temperature management.

Is zero-run the same thing as Tesla's CTC technology?

As mentioned earlier, zero run is the vanguard of domestic CTC technology applications, and looking at the world, Tesla has also accelerated the mass production process of CTC technology. So are the technical lines of the two exactly the same?

The answer is no. Due to some problems that still exist with CTC technology, Zero Run has chosen a relatively conservative route when promoting its mass production applications, that is, the battery cells are still formed into modules before being integrated into the vehicle chassis. This practice is known as MTC (Module to Chassis).

In addition to avoiding safety risks, the technical route adopted by Zero Run has the characteristics of easier mass production and better maintenance convenience. After a problem occurs with a single cell, the engineer can open the lower cover of the battery pack and remove the problematic module for replacement or repair. In the manufacturing process, the vehicle assembly process and battery pack fixing method do not need much change, and the production line adjustment is more rapid.

Tesla, on the other hand, adopts the most radical CTC technology route at present, that is, it truly integrates the battery cell into the chassis. The cockpit floor becomes the battery pack cover, and the two large castings that make up the front and rear bodies are also connected by the battery compartment. This practice is somewhat similar to the four-wheel drive we used to play with as a child.

The ultimate approach allows Tesla to gain greater advantages in reducing weight, improving the utilization of space in the car and battery packs, but at the same time, there are extremely high requirements for the battery management system, safety redundancy needs to be done more in place, and it is also necessary to consider how to eliminate the psychological burden of users sitting directly on the battery.

The choice of both has its rationality, zero run is in the stage of brand climbing, need to take into account the existing product compatibility, control the cost and price, and further expand market share; Tesla, which is already the top role of new energy, needs to rely on more and more advanced technologies to form barriers and consolidate its position.

In the final analysis, automakers develop CTC technology to compete with battery suppliers for the right to speak. No matter which oem is not willing to become a puppet of the battery supplier, spending a huge amount of money on its own research and development products are finally stuck in the neck by the battery pack.

As ordinary consumers, we can only hope that the automotive industry can solve the problems of low energy density, slow energy replenishment speed and poor cell stability of power batteries as soon as possible.

If CTC technology is a good medicine, then do you really dare to buy a new energy vehicle with a battery pack as a chassis?