Although it has been targeted by countless peers and threatened to surpass, the technological changes led by Musk and Tesla are still the beacon of the smart automotive industry.
On March 22, Tesla's Berlin plant will officially start production. As Tesla's first factory in Europe, in addition to accelerating the pace of Tesla's order delivery in Europe, the Berlin factory will more importantly, Musk's "first principle" will once again be practiced on the production side - front and rear integrated die-cast body process, 4680 battery and CTC battery body integration technology.
Among them, the CTC battery body integration technology, which is regarded by the outside world as another outlet for technological change, has also received greater attention in the gradual exposure of The Berlin-produced Model Y and BYD Seals and Zero-Run C01.
The super-variation of CTP
The so-called CTC, also known as Cell to Chassis, can be simply understood as the battery cell is directly mounted on the chassis.
"The old-fashioned flashlight is a metal shell that houses a standard battery. The metal shell is both the housing of the battery and the structure of the flashlight itself, which can be regarded as a CTC structure. Otherwise, you have to make a battery box and stuff it into the flashlight (non-CTC). The person in charge of new energy technology of a Chinese brand was interviewed by Oxcart.com.
Generally speaking, the assembly relationship of the new energy vehicle power battery from small to large is: battery cell - module - whole pack battery (PACK), battery string parallel to module, module string parallel to PACK, plus power distribution module, battery management system (BMS), etc., from the hardware and software to form a complete PACK.
(The picture is reproduced from the electromotive force "Battery Pack Technology Development Path: From CTP to CTC", invasion and deletion)
Before the CTC program, the most cutting-edge mass production solution was CTP (Cell tp Pack), no module technology, BYD blade battery is the most widely known application of CTP technology.
CTP technology eliminates the module design and directly integrates the battery cell into the battery pack, which in turn is integrated into the body floor as part of the structural parts of the vehicle.
This method reduces the module itself side plates, end plates (module structural parts) and the original used to separate the module and help the module connection of beams, longitudinal beams (battery packaging with support structure) and other materials, the entire battery structure is greatly simplified, the use of space is released, the same size of the battery pack capacity can be expanded, the quality of the battery pack can be reduced, resulting in the improvement of battery energy density and cost reduction.
According to data released by BYD, under the condition of a certain volume, the energy density of blade batteries is 50% higher than that of traditional lithium iron phosphate batteries, and the cost of construction is reduced by 30%.
Further to the CTC scheme, the box of the original battery system is merged with the body structure, and the body floor is used as the battery cover, or the battery pack has a separate upper cover instead of the body floor, and the degree of integration has been increased as never before.
Cui Dongshu, secretary general of the Association of Automobiles, pointed out to the oxcart network: "CTC technology is a relatively strong integration technology, which makes the battery energy density more effectively improved, the vehicle design more lightweight, and the formation of a more independent personalized design for the whole vehicle, which is a better thing for car companies, and also makes the car and battery design more effectively matched." ”
Tianfeng Securities believes that the CTC solution is an important development direction for the future of electric vehicle battery group technology. With the improvement of the requirements of electric vehicles for convenience and lightweight, CTC will gradually become an important direction for technology research and development and application.
According to data from a CTC integrated chassis manufacturing company, its 1.0 product has achieved a 15% weight reduction in the body and a 20% reduction in costs.
Tesla proofing, BYD opened
Looking at all potential players at home and abroad, the closest to mass production is still the "pioneer" Tesla.
At the Giga Fest event held at the Berlin factory last year, Tesla demonstrated the 4680 Structural Battery (CTC) program - the 4680 battery pack cancels the module design, the battery cells are densely arranged in the chassis of the vehicle, the battery "upper cover" shoulders the functions of sealing the battery and the body floor, and the seat can be directly mounted on the battery pack.
(Schematic of 4680 Structural Battery, from Inside EVs)
After the adoption of the CTC scheme, the rigidity and thermal runaway management of the battery pack as a structural part have higher requirements.
From Tesla's patent "INTEGRATED ENERGY STORAGE SYSTEM" (patent number US 2021/0159567 A1) published in June last year, it can be seen that its solution is to fill the battery cells with resin materials between the cells and the upper and lower cells to enhance the structural support while playing a role in thermal protection; and in terms of thermal runaway management, it is equipped with 8 pressure relief valves on the side of the battery pack in order to open when thermal runaway occurs and reduce the risk of battery fire.
In addition, the cell connection was changed to Busbar connection; the serpentine tube arrangement was parallel to the axle direction, the flow resistance was reduced by reducing the length of the serpentine tube, and the cooling uniformity was increased, which also demonstrated Tesla's preparation for mass production CTC technology.
(4680 battery cell arrangement, the source marked in the picture see the lower right corner)
In Q2 last year, Musk announced that he would no longer attend the follow-up earnings meeting. After only one quarter, Lao Ma appeared again in the 2021Q4 earnings meeting because he wanted to make an update to the product roadmap. In the absence of a new car release, the only thing that can make Musk personally come out of the mountain is the first Model Y equipped with the 4680 Structural Battery (CTC) program.
In a tweeted reply that was about to be overwhelmed, Musk mentioned, "The new Model Y's structural battery will be another level of product." ”
And in the hot soil of China that is most likely to be stirred after the mass production of Tesla CTC technology -
In the Ningde era, the world power battery giant will not let go until 2025 to come up with mature products.
At the end of last year, Zeng Yuqun revealed that the CTP technology of the Ningde era has been upgraded to the third generation, and around 2025, the Ningde era will launch the fourth generation of highly integrated CTC battery system. By 2028, it is planned to upgrade to the fifth generation of intelligent CTC electric chassis system.
BYD, a pioneer in battery technology, a perfect layout of the whole industry chain, and a brother of the first generation of Chinese new energy vehicles, only inadvertently revealed in the unofficial caliber that seals will be equipped with this latest technology. Even in the important moment of the previous release of e-platform 3.0, this point was only brushed over with "battery body integration".
Therefore, from the official caliber, the first domestic manufacturers to eat crabs will be zero run C01. The C01 will be unveiled on the eve of the Beijing Auto Show, and the current promotional prefix is "the first mass production model to adopt the CTC solution."
From the perspective of other international car companies, Volkswagen and Volvo have also begun to have a layout - Volkswagen announced at last year's Power Day that it will mass-produce standard batteries in 2023, while optimizing the battery system structure in the form of CTP and CTC; while Volvo confirmed the introduction of square shell CTC process in a new battery factory built in cooperation with Northvolt.
Dare to ask where the road is?
In fact, Tesla is the only one that really lands in sight such a futuristic technology.
Industry insiders told the oxcart network that the CTC program as the overall solution in the technical system, the direction is right, but there are three major difficulties in doing it at present: one is that the standard needs to be broken, otherwise the battery system certification cannot be done; the second is that the whole vehicle needs to change the design; the third is that the vehicle production process needs to increase battery installation and testing, which was not done before.
At present, domestic OEMs are actually making gradual attempts along these three difficulties.
A domestic OEMs CTC program developers told Oxcart Network that now Tesla has landed, (their own CTC program) samples have been sent, but there is still a gap from the real CTC - "Although it is CTC, in fact, there is still a bit of CTP shadow, P to C part of the work is done by the main engine factory." ”
The so-called "a little CTP shadow" can be roughly understood as the current "one-step" integration of the battery cell and chassis, but the module and chassis are generally achievable.
At the same time, "the sample has been sent out", which means that the main engine factory does not blindly wait for the testing standard to be released, and innovation must be the product first and the standard.
In addition, the above-mentioned industry insiders also raised another level of problems to the oxcart network, that is, the relationship between the main engine factory and the battery factory that is bound and bound.
He believes that from the two directions of standardization and capacity maximization, standardized batteries, modules (conducive to standardization) and customized battery designs (conducive to capacity maximization) will be born.
From the perspective of the main engine factory, standardized batteries or modules are conducive to the unification of industry specifications, and the security of the entire supply chain is more secure; and from the perspective of large battery factories, customized batteries can be more bound to the main engine factory, and the right to speak will be higher.
It is not difficult to understand why tesla, BYD and other new energy vehicle heads and Ningde era, LG Chem and other power battery heads are competing for this track.
(Picture from Soochow Securities)
Finally, the industry view points out that CTC technology is the same, and the difference lies in the battery resources. If the battery is not standardized, there will always be a dilemma of binding and being bound. In the future, the CTC of the whole vehicle is likely to promote the standardization of the battery, because in the design process, the main engine factory will consciously lean on the standardization of the chassis size.
summary:
In general, CTC is indeed an important direction for the development of battery technology solutions in the future, but at present, only the old horse family in the west can really achieve mass production, and there is no semicolon. At the same time, the upstream and downstream reconstruction of the industry brought about by the new plan, the wrestling of the main engine factory and the battery factory, and the release of targeted testing standards are all new problems in the future large-scale landing to achieve the parity of power batteries and the lightweight of the body.