Super variant form of CTP
The so-called CTC, that is, Cell to Chassis, can literally be simply understood as that the battery is directly installed on the chassis.
"The old flashlight is a metal shell with a standard battery. The metal shell is not only the shell of the battery, but also the structure of the flashlight itself, which can be considered as CTC structure. Otherwise, you have to make a battery box and stuff it into a flashlight (not CTC). " The person in charge of new energy technology of a domestic brand was interviewed by Oxcart. com。
Generally speaking, the assembly relationship of power batteries of new energy vehicles from small to large is: battery-module-whole battery (PACK). The batteries are connected in series and parallel to form a module, and the modules are connected in series and parallel to form a battery pack. Together with power distribution module and battery management system (BMS), hardware and software constitute a complete package.
Before the CTC scheme, the most advanced mass production scheme was CTP(Cell tp Pack), and there was no module technology. BYD blade battery is the most widely known application of CTP technology.
CTP technology directly integrates battery cells into a battery pack by canceling the module design, and the battery pack is integrated into the body floor as a part of the vehicle structure.
In this way, materials such as side plates and end plates (module structural members), cross beams and longitudinal beams (battery packaging and supporting structures) originally used to separate modules and help modules connect are reduced, which greatly simplifies the whole battery structure, releases the utilization space, expands the battery capacity of the same size and reduces the battery quality, thus improving the battery energy density and reducing the cost.
According to the data released by BYD, compared with the traditional lithium iron phosphate battery, the energy density of the blade battery is increased by 50%, while the manufacturing cost is reduced by 30%.
Further to the CTC scheme, the box of the primary battery system is combined with the car body structure, and the car body floor is used as the battery cover, or the battery pack has an independent cover to replace the car body floor, which is unprecedented in integration.
Cui Dongshu, Secretary General of the Federation, pointed out to Oxcart. Com: "CTC technology is a relatively integrated technology, which makes the battery energy density more effectively improved, the vehicle design lighter, and forms a more independent and personalized design for the vehicle, which is a better thing for the vehicle enterprises and also makes the vehicle and battery design more effectively matched."
TF Securities believes that CTC scheme is an important development direction of battery grouping technology for electric vehicles in the future. With the increasing demand for convenience and lightweight of electric vehicles, CTC will gradually become an important direction of technology research and development and application.
According to the data of a CTC integrated chassis manufacturing company, its 1.0 product achieved 15% body weight reduction and 20% cost reduction.
Tesla proofing, BYD opening
Looking at all potential players at home and abroad, the pioneer Tesla is still the closest to mass production.
At the Giga Fest event held at the Berlin factory last year, Tesla demonstrated the 4680 structural battery (CTC) scheme-the 4680 battery pack canceled the module design, and the batteries were densely arranged in the vehicle chassis. The battery "upper cover" shouldered the two functions of sealing the battery and the body floor, and the seat could be directly installed on the battery pack.
After adopting CTC scheme, the rigidity and thermal runaway management of battery pack as a structural member have higher requirements.
According to a patent "Integrated Energy Storage System" (patent number US 20210159567A1) published by Tesla in June last year, the solution is to fill resin materials between cells and above and below cells to enhance structural support and play a role in thermal protection. In the aspect of thermal runaway management, one side of the battery pack is equipped with eight pressure relief valves, which open when thermal runaway occurs, reducing the risk of battery fire.
In addition, the battery is changed to bus connection; The arrangement of the serpentine tubes is parallel to the direction of the vehicle axle. By reducing the length of the serpentine tube, the flow resistance is reduced and the cooling uniformity is improved, which also shows Tesla's preparation for mass production of CTC technology.
Last year, Q2 Musk announced that he would no longer attend the follow-up earnings conference. After being absent for only one quarter, Ma Lao appeared at the 20021Q4 financial report meeting because he wanted to update the product roadmap. In the absence of a new car release, only the first Model Y equipped with the 4680 structured battery (CTC) scheme can make Musk personally go out.
In a Twitter reply that is about to be overwhelmed, Musk mentioned that "the structural battery of the new Model Y will be another level of product."
In this hot land of China, Tesla CTC technology is most likely to be stirred after mass production-
The undisputed world power battery giant Contemporary Ampere Technology Co., Ltd. will not produce mature products until 2025.
At the end of last year, Zeng Yuqun revealed that CTP technology of Contemporary Ampere Technology Co., Ltd. has been upgraded to the third generation. Around 2025, Contemporary Ampere Technology Co., Ltd. will launch the fourth generation of highly integrated CTC battery system. By 2028, it is planned to upgrade to the fifth generation intelligent CTC electric chassis system.
BYD, a pioneer in battery technology and a complete industrial chain layout, is the first generation of new energy vehicles in China, but it is inadvertently revealed in unofficial terms that seals will carry this latest technology. Even at the important moment before the release of E platform 3.0, this point was only taken away by "battery integration".
In this way, from the official point of view, the first domestic manufacturer to eat crabs will be Zero Run C0 1. C0 1 will be released on the eve of Beijing Auto Show. At present, the promotion prefix is "the first mass production vehicle adopting CTC scheme".
From the perspective of other international car companies, Volkswagen and Volvo have also begun Power Day out-Volkswagen announced last year that it will mass-produce standard batteries in 2023, and at the same time optimize the battery system structure through CTP and CTC; On the other hand, Volvo has confirmed that it will introduce square-shell CTC technology into a brand-new battery factory built in cooperation with Northvolt.
Where is the road?
In fact, such future technology is really in sight, and only the Tesla family.
The insider told the ox cart. Com believes that CTC scheme, as the overall scheme in the technical system, is in the right direction, but there are three major difficulties in doing it at present: first, it is necessary to break through the standards, otherwise it is impossible to do battery system certification; Second, the whole vehicle needs to change its design; Third, the vehicle production process needs to increase battery installation and testing, which was not available before.
At present, domestic OEMs are actually trying step by step along these three difficulties.
The research and development personnel of CTC scheme of a domestic main engine factory told Oxcart. Tesla has landed now. Although the sample has been sent out, there is still a gap from the real CTC-"Although it is CTC, there is actually a shadow of CTP, and part of the work from P to C is completed by the main engine factory."
The so-called "a little shadow of CTP" can be roughly understood as "one step in place" to achieve the degree of integration from battery to chassis, but the module to chassis can be achieved.
At the same time, "samples have been sent" means that the OEM does not blindly wait for the release of testing standards, and innovation must be product first and standards first.
In addition, the above-mentioned insiders also raised another question to Niuche.com, that is, the binding and tied relationship between the main engine factory and the battery factory.
He believes that standardization and capacity maximization will lead to standardized batteries, modules (conducive to standardization) and customized battery design (conducive to capacity maximization).
From the OEM's point of view, standardized batteries or modules are conducive to the unification of industry norms, and the safety of the entire supply chain is more guaranteed; From the perspective of a large battery factory, customized batteries can be better bound to the main engine factory and have a higher voice.
It is not difficult to understand why the heads of new energy vehicles such as Tesla and BYD, and the heads of power batteries such as Contemporary Ampere Technology Co., Ltd. and LG Chem are all rushing to this track.
Finally, the industry point of view points out that CTC technology is the same, and the difference lies in battery resources. If the battery is not standardized, there will always be the dilemma of binding and being bound. In the future, CTC may promote the standardization of batteries, because in the design process, the OEM will consciously standardize the chassis size.
Summary:
Generally speaking, CTC is indeed an important direction for the development of battery technology solutions in the future, but at present, only the old horses 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 by the new scheme, the wrestling between the main engine factory and the battery factory, and the release of targeted testing standards are all new problems for large-scale implementation in the future to realize the parity of power batteries and the lightweight of the car body.