Text | Whoops
Since Xiaopeng got into an unpleasant fight with Tesla, Zero Run has become the one that most resembles a "Tesla disciple".
At the beginning of April, Tesla just held the cyber Rodeo opening event at the Texas Gigafactory, and the new version of the Model Y, which took the lead in switching to the 4680 cell CTC battery pack, is naturally the protagonist. Only half a month later, zero running on the other side of the ocean released the CTC battery technology that will be installed in the new car C01, which has the potential to cut off the "master".
Improve, improve, or xx's improvement
The so-called CTC, that is, Cell-to-Chassis, was mentioned in "The Most Difficult Level to Do Batteries, is the Name", which is directly "to" the chassis /chassis (chassis) by the cell . The battery pack and the body chassis are integrated at this time, you have me, I have you, you are me, I am you.
Most of the truths in the world are the same, and removing the intermediate redundant structure will always bring about an increase in efficiency, weight, space and so on. Tesla's original statement was that the new model Y, which uses an integrated die-cast front/rear body, 4680 battery cells and CTC battery packs, has reduced weight by 10% and increased battery life by 14% (note that CTC itself is not only responsible).
The number given by the zero run side is also very beautiful, CTC makes the endurance increase by 10%, the vertical space of the vehicle increases by 10mm, and the battery layout space increases by 14.5%. In addition, on the basis of the above, the zero-run CTC also increases the body torsional rigidity by 25%, and the lightweight coefficient increases by 20%, which is not mentioned when Tesla Amway CTC, as to whether it is not improved or too lazy to say, we do not know.
Anyway, in a word, I want to say cow B.
What would the world be like without CTC?
Whenever a company (not limited to car companies) proposes a breakthrough new technology, in front of those sparkling beautiful data PPT, you need to calm down and ask yourself:
What was everyone in the industry doing before this new technology came along? Why didn't anyone think it was possible to do this before? Is it that others did not expect it, or is there any reason why others are reluctant to do it? Will there be any cost to this? If there is no cost and compromise why only you are a big smart? (A recent case is "Once the skateboard chassis is shot, there is no car-building anxiety?") 》）
It is not at all a disparagement of innovation, because the history of finding complete cases can be answered one by one, and it still seems reasonable and promising.
Just want to emphasize: only by raising and thinking about these few questions and clarifying the most basic context of the development of this field, you – obviously unable to know all the power – will it be possible (but it is possible) to initially determine whether a new technology that seems to be exploding or explosive is a real industry-breaking revolution or a ruthless PE/VC harvester.
The latter is also known as the reverse harvesting of dropout pseudo-nerds against highly educated turtles.
Pull away, hug back to CTC.
Today's most conventional electric vehicle battery system is like this: the smallest indivisible unit is called the cell / monomer / cell, according to what it looks like can be divided into cylinders, soft bags, square shells and other categories, we are familiar with 18650/2170/4680, etc., is to describe the specifications of the cylindrical cell.
A module on the Tesla Model S
Several cells/cells are densely arranged to form a module/module, and the battery power demand of pure electric vehicles is large, so several modules are often needed. These cell modules are placed inside the metal housing, plus cooling, circuits, battery control and other components, forming a complete battery pack/pack.
The battery pack/pack is the final product of the battery system, so the final step in the whole process is to load this "package" into the car.
Under the premise of the same cell specifications, if more cells are used to form a larger module, the number of modules that can be placed under the same size battery pack is reduced, but the total volume occupied by the gap between the module and the module is also smaller, so the battery pack can accommodate more cells, that is, a larger amount of power - this is the so-called "big module" battery pack.
Further, directly remove the gap between the module and the module, so that all the cells are tightly arranged into a huge module, the battery pack has and only one module, there is no module /module concept, the battery pack / pack is directly composed of a large number of cells / cells - this is the so-called CTP, Cell-to-Pack.
Tesla's CTC battery pack, CTC is also CTP
Note that when CTP is implemented, the "de-middleing" at the pack level is over: the cell cell is the smallest indivisible monomer, and the battery pack pack is the final complete finished product. The next step of CTC, which essentially goes beyond the "battery pack pack" level, is the integration between the battery system and the body (outside the battery system), and the hand extends outward from the battery pack itself.
Non-CTC conventional battery packs, whether oil-to-electricity or pure-electric platforms, can be considered "hanging" or "embedding" the body chassis/car body. Between the battery pack and the car body, the connection method is usually used such as bolts. You've definitely heard of some electric vehicles replacing battery packs due to malfunction or attenuation, and naturally require non-destructively removable means of connectivity.
The battery pack of the Porsche Taycan is bolted to the chassis by 28 bolts
This conventional practice has been used for many years, and it is also normal to talk about the early development of electric vehicles: the car, before the use of oil, the engine fuel tank screwed up; now with electricity, it is natural to screw the battery (package) up. Especially in the early stage of the development of electric vehicles, it is common for battery systems to have problems and need to be maintained, even if a battery cell is broken and needs to be repaired, the entire battery pack must be opened, "packaged and screwed up" is the logic of normal people.
But this conventional approach also creates significant structural redundancy, with a large sheet of metal on the floor at the bottom of the body and a whole plate on the housing on the battery pack. The role of the two is actually a lot of overlap, the body floor is protective of the top of the battery pack, and properly designed to protect the occupants from battery explosion damage (or is it that the two layers of the board will never be safe, nor is it).
Chevrolet Bolt/Buick Micro Blue 7's SMC battery pack covers
In fact, at present, some manufacturers' battery packs, the upper shell is made of lighter non-metallic materials such as fiberglass. They are protected by the body structure and do not need to bear the main impact resistance, but are only responsible for sealing the battery pack and suppressing the threat of the battery pack upward to the crew compartment.
At the feet of the occupants is a metal body floor, then a hard board on the housing of the battery pack, and then there is the thing that really provides electricity (cell cell). And CTC, simply and rudely speaking, is to integrate these two boards into one piece - yes, a lot of technical analysis is a mess, and the road is actually such a thing.
CTC, zero run did not go tesla's way
"Turning two boards into one board" is as simple as it is understood, but it does not mean that CTC is easy. Directly the body floor as the battery pack cover, we do not talk about this "floor and upper cover" is calculated as a body or a battery, the connection between the battery system and the body can no longer be just a bolt.
Zero run CTC, note that the exploded diagram is without a battery pack cover, and the body floor itself is used as the upper cover
The reason is simple, the bolts are not enough to guarantee high standard sealing performance, and need to be combined with other connection methods with better sealing – the result is that almost non-destructive disassembly and replacement can no longer be achieved.
Previously bolted together, two separately sealed parts were: the bottom of the body was welded together, and the water you drove would not seep through the floor slit; the battery pack was strictly sealed, IP68 at every turn. As for the requirements between the two, there is not so high a requirement, the bolt installation is also convenient to disassemble and convenient, and the battery problem can even be directly replaced by the whole package.
CTC currently has two main implementation methods, one is to "first seal the battery pack, the body side of the leak first", the other is "first lay the body floor, the battery is first open". Academician Ouyang Minggao called the former CTC, and believed that the latter should be called "CTV (vehicle)", and we will not distinguish between them here.
From the 2022 electric hundred people will Ouyang Minggao, note that the "power exchange" here does not refer to the kind of Weilai
The first solution is the way Tesla uses, first to meet the sealing needs of the battery system. Looking only at the battery side, the production and manufacturing, including the sealing, are not much different from the previous non-CTC battery packs, so it is considered that the risk is more controllable. However, because it is necessary to manufacture a complete battery pack first, the shape of the battery pack, especially the upper shell, will be limited to a certain extent, and the improvement space for the efficiency of the vehicle/body structure may not be as good as the second plan (of course, it may be too early to talk about this at the moment).
Note that in 9A, the body part is floorless, different from the Taycan above
Tesla showed the CTC battery pack disassembled, and the seat was mounted directly on the housing on the battery pack
The second option is today's zero-run option, the body is a complete body sent over, and the battery pack is a "open" state without a lid at this time. While the battery part is installed to the body, the lower housing of the battery pack is sealed with the body floor and the upper shell. This practice prioritizes crew compartment tightness, but it is clear that battery sealing is far more important than crew compartment at this time. When installing and sealing the battery part, the body structure has been basically completed, and the installation process will be more complicated and cumbersome to take into account such a large "burden" on the body.
Therefore, compared to the solution one used by Tesla, the CTC of zero running carries more unknown risks.
Of course, the second plan also has its own advantages, because the floor part is welded to the body to become one, you can easily design a variety of cross-stringer structures, and there is no need to consider the battery pack when connecting the body as in the first plan to avoid the surrounding structure, compared to the body of the first plan "borrowing" the battery cover will have the advantage of structural efficiency. In other words, in terms of combining weight, material process (cost), stiffness targets, etc., better body performance can be obtained at the overall level (the same cost is lighter, the same weight is stiffer, etc.).
Zero-run CTC, the body is complete, the battery is open-covered
Black technology, but not so black
CTC can indeed significantly improve the overall performance of electric vehicles.
First, for battery systems, a layer of redundancy is removed, and the battery system can have more space, or/and can give up space in the height direction to the crew compartment, or/and lower the body height and increase ground clearance. In short, the space is more compact, how to use it to see the mood of the boss.
Secondly, the redundancy of just one layer of board is not obvious in vertical space, but the weight reduction is real. The lightweight advantage of CTC's "losing a layer of board" is quite tempting for pure electric vehicles. The increased reinforcement effect of CTC on the body structure will make the body material required under the same stiffness target less, and indirectly promote lightweight.
Finally, CTC enables (or forces) the battery pack housing to be connected to the body in a more secure way – after all, the shell itself becomes part of the body, which increases the contribution of the battery pack to the stiffness of the body. In fact, the conventional battery pack can already bring about a 50% stiffness increase, improve the vehicle NVH and other related performance, after the CTC battery pack for the body stiffness contribution may be greater.
The battery pack connection method of the MEB pure electric platform
Since CTC technology is so tempting, then back to the beginning of the question, why have there been sporadic car companies to start applying it until today?
We have explained the difference in sealing methods, zero-run CTC is a more risky way, even if the Tesla CTC battery pack is less difficult to seal, there is a certain risk of crew compartment sealing, especially after long-term use of durability. It is entirely possible that these risks have been addressed, of course, but no one can conclude that they do not exist until it is long enough.
The problem of after-sales maintenance is not difficult to understand. If the battery fails in the conventional battery pack, replacing the battery pack is a matter of tightening the bolts, and even weilai relies on power replacement to replenish energy. After CTC, once there is a condition inside the battery pack, replacing or opening the battery pack must mean disassembling and replacing the body body. With the hidden danger of secondary sealing, whether the disassembly of the CTC battery pack will affect the body structure, no one can give a conclusive answer now, and no one knows whether there is a problem before the problem appears.
Of course, you can say that you buy an electric car only for two years to change, but the entire value chain is open, as long as the electric car has been driven, sooner or later it will encounter battery failure, if the tail end of the maintenance work is difficult and costly, the entire cycle is shortened or the cost of the cycle has increased, it will inevitably be transmitted to the front end of the new car retention rate, there is no completely unaffected way to buy a car.
But then again, pointing out and acknowledging these costs and risks is not the same as denying that CTC technology is the trend of the times. The various technological advances in this world have rarely been all-round without sacrifice or compromise. If everything is based on the purpose of security and low cost as the creed, today's streets should be full of all-steel bodies, naturally aspirated, carburetor injection, manual transmission of the original car, technological progress and social development will be slowly outrageous.
Technological progress for the promotion of social development, must have a sacrifice, only when someone is willing to "risk" for the sake of "sweetness", can create a spiral of opportunities for comprehensive perfection. Conversely, we cannot simply make new technologies mature as soon as possible, and hide their temporary immaturity and unknowns from people. There is no one-way correctness in this world, only to find a balance in contradictions, to weigh between advances and retreats.
CTC belongs to the underlying underlying technology of "utility post-production", which is not intuitive at a glance. In other words, the impact of CTC on the performance of the whole vehicle is transmitted through "several hands". CTC will reduce weight, increase space, increase endurance, improve stiffness and improve NVH, but you will never know which aspects of the many advantages are only changed by CTC. There is no parallel universe that is exactly the same except for no CTC to compare to you.
You can only say CTC bull B, but you can't quantify how much CTC brings to the B value of cattle. CTC can reduce weight, but you can also put the weight lost into more batteries, lay more sound insulation materials, install larger horsepower motors; CTC can improve stiffness, but you can also save materials in advance to reduce the stiffness of the body body, and then use CTC to make up for it; CTC's contribution to lightweight and stiffness, car companies can use to improve performance, but also can be used to save costs, or both, which is more or less to see the choice.
In the end, consumers pay for the actual performance and performance of the vehicle, while CTC and the like are only technical means to achieve it. Even whether it can be realized or not is another matter, and it is not uncommon to exhaust advanced technology, subjectively work hard, and be willing to make a lump of success. So CTC is actually not going to be the protagonist in the spotlight — unless it's forced to be rendered as some kind of black technology that changes everything.
Volkswagen may only try CTP and CTC on the next generation platform SSP
CTC itself is not so advanced cutting-edge technology, three or two sentences down the children can understand a rough idea, most of the large car companies have the technical strength of CTC, but their respective power, resources and situations are different, the rhythm and practice are also different.
Tesla uses A CTC battery pack on the Model Y, and the background is that the Model 3/Y kills the four parties to earn soft, and it is not inevitable to choose to break through and further increase the advantage at this time. The new plants in Texas and Berlin did not have the sunk costs of the old equipment and also gave a good opportunity for product iteration. As for aggressive risks and maintenance costs, when did Tesla ever care about that? When does Tesla need to care about this?
The zero-run situation is the same or different. The same is that there is no sunk cost, because the sales of models before zero run are not much, and the subsequent revenue generation ability of models other than C11 is also limited. At this time, the first to change lanes, zero run decided to be easier than those head car companies, and the late starter also has the advantage of being a late starter.
The difference is that zero run needs to take more risks and break more doubts, especially choosing a CTC method that is more risky than Tesla, and zero run has not accumulated enough word of mouth and market trust (although Tesla's reputation in manufacturing is not good, but it is enough). If Tesla engages in CTC, it is the lack of a decent competitive environment of "try to try", then the use of CTC for zero running is more or less mixed with a little bit of risk in order to break the game and exchange risk for product competitiveness.
There is nothing good or bad, admitting that runners are more likely to be unstable, and wishing that this rush is finally worth it.