Battery revolution of BYD CTB technology, is it the best
- Development trend of power battery
- CTP, CTC, CTB, which one is the best?
- BYD CTB battery technology
- Summary and outlook
Nowadays, affected by the shortage of many automotive raw materials such as automotive-grade chips and wiring harnesses, the research and development progress and production progress of world car companies have been affected to varying degrees. As a leader in the field of new energy vehicles and a leader in the battery industry, BYD is very strong, and Byd blade battery is extremely competitive.
Development trend of power battery
The change from oil to electricity and the change in power mode brings about an increase in power. The biggest advantage of adding the form of cell-module-battery pack is to distinguish the cell according to the form of the module for better performance. Management and post-maintenance are relatively simple.
However, in order to connect with each other in series, it is inevitable to use a large number of cables and structural components for connection, and there will be many redundant structures, which not only reduces the utilization rate of the battery pack, but also makes the entire power battery very heavy.
Similarly, the oil-to-electric models using the above-mentioned “small module” battery packs inevitably have some problems, namely, the battery life problems caused by the surge in weight and low space utilization, the outstanding chassis that affects the appearance, and the waterproof insulation of the cells. Safety issues such as thermal intractability.
In order to solve the above problems, the concept of CTP has been proposed, that is, the modules are omitted or reduced, and the cells are directly arranged in the battery pack. For example, BYD’s blade battery is one of the examples. It directly adopts a module-free design, which greatly reduces the internal cables and structural parts, and effectively improves the volumetric energy density of the battery pack.
As the main carrier of battery energy density, in theory, as long as the number of cells is sufficient, the battery life of the vehicle can be effectively improved. However, there are many problems involved. Take a fuel vehicle as a comparison example: a fuel vehicle with a 60L fuel tank weighs only 60kg, and a model with a fuel tank weight of 100kg is already a large SUV. In contrast to the power battery, a battery pack with a battery life of only 400km can easily weigh more than 300kg.
At this point, two different technologies began to emerge. One is CTC technology headed by Tesla and Leapmotor, and the other is CTB technology headed by BYD. The two technical routes seem to be the same, but they are actually different in structure and specific performance.
CTP, CTC, CTB, which one is the best?
CTP is a technology aimed at simplifying the battery pack, but there are also many intermediate steps to install the battery pack on the chassis, and the chassis needs to be redundantly designed. This is the CTC (Cell To Chassis) technology, that is, the cells are directly integrated on the chassis.
The main difference between the CTC and the traditional battery installation method is the elimination of the battery pack upper cover or the cockpit floor, which further simplifies the body cables and structural parts. Different manufacturers have slightly different handling methods. For example, Leapmotor’s CTC solution is to cancel the upper cover of the battery pack, while Tesla’s CTC solution is to cancel the cockpit floor. And there is another odm best lithium battery manufacturer which is specialized in lithium iron phosphate battery and lithium battery/ pack.
Tesla’s CTC solution, also known as structural battery, uses 4680 batteries and integrates the cabin beam and the seats in the battery pack. In other words, it is also CTC, Tesla’s integration is still higher than that of Zero Run, but there is almost no possibility of battery repair or replacement.
BYD’s CTB (Cell To Body) is actually somewhat similar to CTC technology, in that the cells are directly installed in the chassis. However, the difference is that CTC still treats the battery pack as a separate object to be protected, while BYD’s CTB uses the high safety and structural strength of the blade battery to integrate it into the overall design of the body.
The battery cell of the blade battery and the entire battery pack form a structure similar to honeycomb aluminum, which itself can play the role of a body structure.
Therefore, CTP is just a battery pack technology, while CTC and CTB are a type of vehicle technology. Although in terms of integration, CTB is slightly inferior to Tesla’s CTC solution, which means that BYD’s manufacturing cost will be slightly higher than Tesla’s. However, in terms of structural safety and maintainability, BYD’s CTB is still better. Obviously, this solution is more beneficial to users.
BYD CTB battery technology
Taking electric vehicles as an example, the most direct way to increase the battery life is to increase the battery capacity. However, the increase in battery capacity is accompanied by an increase in the weight of the battery, which in turn leads to an increase in power consumption.
Therefore, the higher the battery capacity, the smaller the gain for battery life. At the same time, the larger the battery capacity, the higher the potential safety hazard in theory.
Therefore, how to improve the comprehensive performance of electric vehicles on the premise of “subtracting” electric vehicles has become a difficult problem in the current development of electric vehicle technology. As a leader in new energy vehicles, BYD’s CTB technology provides a standard solution.
The so-called CTB technology, that is, the integration of the battery and the body. To put it bluntly, it is to integrate the battery pack with the chassis, so that the battery pack directly becomes a part of the body structure. The power battery is both an energy body and a structural body.
So, what are the advantages of CTB technology? First of all, by canceling the design of the module and the upper casing of the battery pack, more cells can be loaded in a limited space, thereby increasing the battery capacity and increasing the cruising range.
Taking the BYD Seal equipped with CTB technology as an example, the optimized structure increases the utilization rate of the power battery system by 66%, and at the same time increases the energy density of the system by 10%, thereby achieving a cruising range of 700km.
Secondly, CTB technology can reduce the weight of vehicle battery components while enhancing the overall strength of the vehicle. In addition, CTB technology adheres the blade battery to the tray and the upper cover to form a sandwich structure similar to the honeycomb aluminum plate.
In this way, the blade battery with high safety, coupled with the stronger sandwich structure formed by CTB technology, The structural strength of the entire battery pack is greatly improved.
Taking the BYD Seal equipped with CTB technology as an example, the torsional stiffness of its body reaches 40,500N m/°, which not only greatly improves the safety of the whole vehicle, but also makes the vehicle’s handling response more flexible.
With the support of CTB technology, the sandwich-structured battery pack can be crushed by a truck weighing up to 50 tons without emitting smoke or fire, and the cells are still in a safe state, and can still be used normally after being loaded again, which shows its high strength.
In addition, a hidden advantage of CTB technology is that, because the structure of power battery packs is not as complicated as that of traditional battery packs, the usage of parts and components is reduced, which can make production more efficient. Compared with the model, the cost-effectiveness The advantages will be more obvious.
Compared with the CTP technology that directly omits the module and the CTC technology battery pack is still an individual that needs to be protected, BYD’s CTB technology is obviously more advantageous in terms of overall structure.
BYD CTB technology can be seen as an evolution based on CTP technology. Compared with CTC technology, although the battery is also directly installed in the chassis, BYD can make use of the high safety and high structural strength of the blade battery to make the overall body strength and safety higher.
Summary and outlook
To sum up, Tesla’s CTC technical solution is relatively radical, with high integration, but relatively poor flexibility and poor maintainability. Leapmotor’s CTC is not as lightweight as Tesla’s, and the risk of battery compartment sealing performance is high.
BYD’s CTB solution is just right in terms of light weight and integration, and has high security, which is more in line with future development trends. The integration of battery and body will take a different path from battery swapping. Whether the current battery density and performance can support the vigorous development of this technology still needs to be verified.