There are two main types of CTC battery integration schemes, the first is battery pack chassis integration, which is to directly integrate the battery pack into the chassis frame to replace the floor, or directly use the crew compartment floor as the upper cover of the battery to realize the integrated design of the body floor and chassis;
The second is the integration of the battery cell chassis, which is welding or gluing the shell of the battery cell to the chassis structure, changing the manufacturing form of the battery. The former has high reliability, while the latter has obvious integration advantages but is technically difficult and cannot be replaced.
CTC is essentially the idea of chassis platforming, and theoretically, the power can be increased by 5% on the existing chassis technology, and the degree of vehicle electrification continues to be improved.
In 2018, when electric vehicles were gradually popularized, Jiewei and Suzhou Konip had a patent layout for this technology. On August 20, CATL proposed the CTC plan, allowing the electric vehicle industry to focus on this concept; The emphasis on this technology at Tesla Battery Day in September brought the product’s popularity to a climax, and mass production is expected in 8. The new force Leap C9 will lead Tesla to become the first production model equipped with CTC battery technology. Tesla will also launch a new model Y with an integrated stamping body + CTC structure this year, and the mass production of CTC is ready to go.
Key enterprise analysis
The traditional MTP battery module stacking technology requires several square cells to be combined to form a module, and then multiple modules are installed to form a battery pack. Due to the requirements of safety and stability, each module is protected by a metal shell and is equipped with cooling fans, heat dissipation channels, insulation devices, etc. In the battery pack, it is also necessary to install multiple additional modules, a large number of screws, and other connectors. The overall energy density of the power battery is greatly reduced, and the cost per unit of electricity is increased.
CTP’s company progress and patent layout scheme directly forms a single cell into one or several arrays (modules) and installs them into the battery pack, which greatly reduces the number of modules, eliminates the process of forming modules and then installing them into the battery packs and the cost therein, and can be installed on new energy vehicles after forming battery packs. After using CTP technology, the space utilization of the battery pack is improved, the volumetric energy density is improved, and unnecessary module parts are reduced, but the requirements for technical capabilities are improved, and the safety performance is not as good as the combination of module stacking.
Tesla, longitudinal large module
The battery modules of early models are mainly arranged horizontally, with many modules and low space utilization. The Model 2016 that left the factory in 3 completely changed the previous battery pack structure, changing the layout to a longitudinal large module, and the whole vehicle only has four power battery modules, using a long strip of large modules to challenge the available space of the battery pack. The successful application of the Tesla Model 3 proves the feasibility of large or non-module battery packs.
CATL, large module scheme
CATL’s CTP scheme uses multiple long grooves, adjacent long grooves are thermally isolated by separators, and the battery is installed in the groove to form a large module and fix. At the same time, the cell array is fixed and connected through the fixed connection part, which improves the strength of the battery pack, which in turn makes the battery pack better fixed at the bottom of the car and improves the overall stability. On May 2022, 5, Zeng Yuqun, chairman of CATL, said at the results conference that it plans to officially release Kirin batteries in the second quarter of this year. The Kirin battery is the third generation of CTP (High-Efficiency Grouping) technology of CATL, under the same electrochemical system, the Kirin battery has a 5% higher energy density than a large cylindrical battery.
BYD, “blade battery” module-free solution
Another CTP scheme from BYD is to form a power battery pack by simplifying the battery module. First, the single cells are placed in series. In a simplified battery module, the battery module structure includes coolant channels and the length corresponds to the battery pack. Then the simple module is placed in the power battery pack. BYD invented blade cells for its CTP scheme, which are significantly longer and thinner than traditional square cells, and these blade cells are arranged together in an array and inserted into the battery pack like “blades”. The blade cell has a large relative heat dissipation area, and as the thickness decreases, the increase in cell and pack temperature during operation will decrease, and the heat dissipation performance of the battery is significantly improved.
Hive Energy, lamination technology
The CTP scheme adopted by Hive stacks cells into the battery pack, replacing the scheme of forming modules by adding thermal isolation separators to form different cell slots. At the same time, considering the thermal runaway and fire problems in the battery, the heat dissipation of the battery pack is improved, so that the installation slot of each cell has a breathable valve, and the heat dissipation channel is increased. The laminated battery has a higher space utilization rate than the winding battery, so the energy density of the cell is higher, the number of tabs of the laminated battery is nearly twice as much as that of the winding battery, and the internal resistance of the battery will be reduced, and the battery heat generation is small, and the battery life is longer.
Zero runs, big module solution
So far, Leapmotor has launched a total of 3 battery platforms, which support the 3 released cars, namely: S platform, T platform, and C platform. As far as the S platform is concerned, Zerorun refers to Tesla Model S technology, using mature cylindrical 18650 and 21700 cells, horizontal arrangement + two-layer module. As far as the T platform is concerned, the integrated through-through large module scheme is adopted, and the space utilization rate reaches 83%, and the T03 large module scheme is similar to CTP, which is the idea that many models like at present. For the C platform, Zerorun still adopts large module technology, which is called a high-integration integrated large module.
Compared with the traditional MTP technology, the CTP solution has reduced overall cost and improved energy density, but there are still bottlenecks in safety performance and technology research and development. In order to break through the bottleneck and further reduce costs and increase efficiency, the layout of domestic and foreign battery factories and automakers on CTC is also showing a trend of blooming.
Conclusion
The CTC technology uses the car’s underbody as a battery box, integrating the cells into the chassis frame and thus increasing the usable volume. This article includes the basic fundamental of CTC technology with a few models by different companies.
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