"Model 3 is the first car to adopt a domain controller structure, and its volume is also relatively large and typical." Ding Qi, chief analyst of , CITIC Securities' cloud infrastructure industry, told Interface News.
"dismantling car" is contagious in the securities industry. After Haitong International dismantled BYD "yuan" on June 26 and wrote an 87-page research report, CITIC Securities also joined the ranks of car dismantling on July 18.
In the research report of "Tesla Series Research Topics in the New Energy Vehicle Industry: Looking at the Development Trends of Smart Electric Vehicles from the Disassembly of Model 3", CITIC Securities stated that its research department TMTh and the automobile team worked together with multiple companies and institutions to completely disassemble a Tesla Model 3 in two months.
By dismantling Tesla Model 3, this research report analyzes the development trend of smart electric vehicle from 6 aspects.
As a leading manufacturer in the world's electric vehicle field, Tesla has shown unique design ideas in many aspects. In Ding Qi's view, Tesla's domain controller, integrated die-casting, multi-screen and connected smart cockpits will all be the common trends in the future development of smart cars.
1. Domain controller
"Software and hardware must be decoupled , and computing power must move from distribution to concentration."
research report believes that if a car wants to continuously iterate software based on data and user feedback like a mobile phone, the existing E/E architecture will inevitably undergo major changes. The main reason why Tesla Model 3 is the first to move from a distributed architecture to a domain-based centralized architecture is far ahead of many car manufacturers.
body domain
According to Tesla's ideas, each controller should be responsible for controlling the components nearby, rather than all similar components in the entire vehicle. Therefore, Tesla's three body domain controllers are distributed in front of the front body, the left front door and the right front door respectively to achieve nearby control.
Driving Domain
Intelligent Driving is also a major feature of Tesla. This part of the functions are performed through its autonomous driving domain controller (AP). The core of this part lies in the FSD chip independently developed by Tesla, and the remaining configurations are no essential difference from other current autonomous driving controller solutions.
CITIC Securities predicts that in the future, innovation in the autonomous driving field will still be concentrated on the chip end. In addition, innovations in sensors such as lidar and 4D millimeter wave radar can also greatly promote intelligent driving.
cockpit domain
From the continuous approach of Tesla's car machine and games, we can see the first direction of the future cockpit domain development, that is, continue to promote large computing power and strong ecology; the second direction of development is the possibility of integration with autonomous driving controllers. There are quite a lot of signs of the integration of the two, such as Bosch , Denso and other mainstream suppliers have integrated ADAS functions in cockpit domain controllers, and this trend is expected to become popular in the future.
electronic control domain
Model 3 is the first pure electric vehicle to use a full SiC power module motor controller, setting a precedent for SiC applications. The many advantages of IGBT are: Before the launch of Model 3, all new energy vehicles on the world adopted the IGBT solution. Model 3 uses SiC module to replace IGBT module , which accelerates the promotion and application of SiC all-wide bandgap semiconductors in the automotive field. After
Model 3 formed a "demonstration effect", many car manufacturers followed up on SiC solutions. Compared with IGBT, SiC can drive multiple performance improvements and has significant advantages. However, the high cost of SiC restricts the pace of popularization. CITIC Securities predicts that SiC and Si-IGBT may develop simultaneously in the future and complement each other.
power domain
The standard battery life version disassembled this time is equipped with 96 voltage sampling points, the number is the same as Model S. On average, one voltage value is measured in parallel for every 31 batteries. There are 4 battery packs in the whole vehicle, each of which consists of 24 series and 31 battery packs, which put forward high requirements for current equalization and other aspects.
In the future, with the application of 4680 large cylindrical batteries, the number of bicycle batteries will be further reduced, which will help BMS to more accurately control.
2. Wire Harness and Connector
Wire Harness
Reduce the complexity of the wiring harness and rely on innovation in electronic and electrical architecture.
Model 3 re-divides the "domain" and performs cross-domain fusion based on Model S and Model X. Each ECU is no longer divided by function, but is directly divided into four parts: CCM (central processing module), BCM LH (left body control module, LBCM), FBCM (front body control module), and BCM RH (right body control module, RBCM) based on physical locations.
uses a small number of high-performance computing units to replace the dispersed ECU, migrating the functions that need to be implemented into several major modules through software, thereby further improving the set to degrees. Therefore, the wiring harness length of Model 3 is further shortened to 1.5km.
In addition to the architecture adjustment and shortening the length of the wiring harness, it was found that Model 3 uses aluminum wires instead of traditional copper wires in high-voltage wiring harnesses to further achieve lightweighting.
connector
On the connector of the power battery-electric high-voltage wiring harness, the Model 3 uses TE's HC Stak 25.
The structure and function are similar to HC Stak 35. The difference lies in the size. HC Stak 25 is smaller than HC Stak 35. Therefore, the terminal at the socket end of the HC Stak 25 is composed of 20-piece DEFCON terminals (HC Stak 35 is 35 pieces), and different models share the same connector terminal. The connector terminals can quickly complete the assembly of different models through the change of quantity stacking, which reflects the cost control advantages brought by the modular production of connectors. In terms of
material, the Model 3 connector material is nylon plastic material. CITIC Securities believes that the application of metal alloy shells will become more popular in the future.
3. Battery
Model 3 battery pack uses 4 large modules. Compared with the iD.4 X and BMW iX3 battery packs of the same period, it uses large module technology, with higher integration and cleaner internal layout. The battery pack technology is still in the leading position.
4680 While the battery expands its size and increases its capacity, the all-pole ear structure reduces the loss caused by resistance heating and battery cooling, and ultimately the effective energy and energy density of the battery increase. In addition, due to the small heat generation and fast heat dissipation of all poles, physical conditions are created for the 4680 battery to achieve high-power fast charging.
4680 battery achieves an impossible triangle of "high energy density, high magnification and low cost" through new structures and new materials. In the case of achieving high energy density and high magnification, the 4680 large battery cell dilutes the cost of inactive substances, and makes the overall single Wh cost as high as possible, so as to simplify the production process and save costs.
4. Motor electronic control
assembly, Model 3/Y is equipped with a three-in-one drive system for driving motors, motor controllers, and single-speed transmissions, with high integration. In terms of
motors, it has evolved towards high power and low energy consumption, and its performance and cost are continuously optimized. From Model S/X to Model 3, Tesla switched from induction motor to permanent magnet synchronous motor , and the dual motor versions were both induction motors from front and back to induction backward and permanent magnet motor .
At the same time, "Xiao San Electric" is integrated with the battery pack, making the space layout more compact. CITIC Securities judged that with the further improvement of the integration of electric drive products, in addition to the three-in-one integration of motors, motor controllers, and reducer drive systems, power supply devices such as PDU, DC/DC, charger OBC can also be integrated with them to form the evolution of "three-in-one" to "N-in-one".
5. Thermal management
Tesla thermal management system has undergone 4 generations of development and is constantly innovating in structural integration. The fourth generation thermal management system uses eight-way valves to integrate cooling and heating circuits to achieve integrated thermal management of the entire vehicle. The energy efficiency is improved under the eight-way valve design, and the system integration reduces costs.
Tesla thermal management valve class is evolving towards a highly integrated direction, realizing heat distribution with more complex management and control strategies.
6. Automobile body
In terms of body materials and processes, Model 3 uses a mixed body of steel and aluminum, and the manufacturing process is mainly stamping and welding.
lightweight can not only meet energy saving, but also improve battery life. "Aluminum instead of steel" is the best choice; high-pressure die-casting is the most efficient molding method for aluminum alloy materials, and Tesla is the first to propose integrated die-casting.CITIC Securities judged that the overall die-casting cost reduction and efficiency increase is the general trend. In terms of headlights, the Model 3 exterior is matched with both technology and beauty, and the headlights are made of matrix LED light sources. In terms of glass, Tesla's panoramic skylight leads the industry trend and replaces traditional skylights. In addition, CITIC Securities pointed out that the Tesla Model 3 chassis is gradually being controlled in line, and the control of the chassis is the only way to achieve high-level autonomous driving.
