What is the appearance of the car after installing the crossbeam - battery tray?
After the installation of the crossbeam and the battery tray, what is formed is the lower shell structure (Base Tray) of the power battery pack, which is the core load-bearing framework of the entire battery system.
The specific composition and functions are as follows:
Structure definition: The crossbeam is usually welded or integrated into the left and right frames and the interior of the battery tray, together with the longitudinal beam, forming a cage-like framework structure, which is used to fix the cell modules, water cooling plates, and BMS, etc.
Core function: This combination mainly performs the functions of bearing the weight of the battery, resisting impact and preventing bottoming out, and transmitting collision force. In some advanced designs (such as CTB/CTC technology), it is also integrated with the vehicle chassis and directly participates in the torsional stiffness support of the entire vehicle.
Subsequent components are installed on this structure, followed by the installation of battery cells/modules, thermal management systems (such as liquid cooling plates), and upper cover seals, ultimately forming a complete power battery pack.
In summary, "crossbeam + battery tray" is the bottom load-bearing base of the battery pack. After installation, it needs to be further assembled with internal electrical and thermal management components to become a usable battery system.
After installing the crossbeam inside the vehicle battery tray, the core function is to enhance the structural stiffness, distribute the load, and strengthen the battery safety protection. This is manifested in the following aspects:
Enhance structural stiffness and bearing capacity: The crossbeam, together with the longitudinal beam and the frame, forms a framework structure, significantly improving the torsional stiffness and bending strength of the tray, effectively supporting the weight of the cell modules and bearing the longitudinal and lateral loads generated during vehicle acceleration, deceleration, steering, and bumps.
Resist external impact and collision protection: In side impact or bottom scraping conditions, the crossbeam, as a key force-bearing component, can block lateral intrusion forces and prevent the battery pack from being squeezed and deformed; some designs also include collapse energy absorption structures to ensure the integrity of the gas seal and reduce the risk of battery thermal runaway.
Optimize internal layout and thermal management: The crossbeam is used to separate and fix the cell modules, providing space for electrical component installation; at the same time, it can serve as a support base for water cooling plates and other thermal management components, assisting in the uniform distribution of heat and improving system stability.
Participate in the integrated integration of the entire vehicle: In modern CTC/CTB technology, the crossbeam of the tray is deeply connected to the vehicle floor, becoming a part of the vehicle structure, assisting in transmitting collision force and improving the overall safety and space utilization of the chassis.
As technology progresses, the third-generation trays tend to eliminate some internal crossbeams to improve space utilization, but the strengthened crossbeams in key positions are still indispensable structural elements for ensuring battery safety.
When a fault occurs after installing the crossbeam and battery tray in a vehicle, it usually results from welding thermal deformation causing sealing failure, installation surface unevenness leading to high-voltage leakage risks, or structural stress damaging the internal cells. Such problems often occur during maintenance, replacement, or manufacturing assembly and require the focus on the following core risks:
Common fault manifestations
Insulation/leakage alarm: The sealing surface of the tray is deformed due to welding stress, resulting in insufficient compression of the sealing ring, allowing rainwater or car washing water to seep in and causing a decrease in the insulation resistance of the high-voltage system.
Battery fault light on/off/power limit: The bottom plate or crossbeam of the tray is locally deformed, squeezing the internal cells, or the liquid cooling pipes are damaged or cracked during welding/installation, triggering BMS temperature or pressure abnormal protection.
Chassis abnormal noise and vibration: The installation bolt holes are skewed or the support surface is deformed, causing uneven pre-tightening force between the tray and the vehicle longitudinal beam during driving, resulting in metal friction sounds or abnormal resonance.
Charging interruption: The installation surface of the ventilation valve is not flat, causing a water ingress risk, which then leads to an electrical circuit fault, and in extreme cases, may trigger a thermal runaway warning. Visual inspection of seals and deformation: Check if the sealing surfaces at the edges of the tray have obvious warping or concavity, and whether the sealing ring is exposed or broken; Examine if there are any cracks or cracks in the weld seams of the crossbeam.
Measure the installation flatness: Use a level or feeler gauge to detect the fit between the tray and the vehicle installation surface, confirm if the bolt holes are aligned, and strictly prohibit forcefully tightening to cause secondary deformation.
Read the BMS data stream: Connect the diagnostic instrument, focus on checking the insulation resistance value, the voltage balance degree of individual cells, and the coolant flow/temperature, to determine if there is any hidden leakage or thermal management failure.
Airtightness test: If the seal is suspected to be damaged, a pressure retention test of the battery pack should be conducted to confirm if there are any leakage points (note: non-professionals should not disassemble it themselves to avoid damaging the explosion-proof valve). Handling suggestions
Stop charging immediately and avoid high-load driving: If an insulation fault or battery fault indicator is reported, there is a fire hazard. The vehicle should be towed to a professional service center as soon as possible.
Do not attempt to correct deformation by yourself: Once the aluminum tray is deformed, forcefully tapping for correction will damage the material's crystal structure and reduce the collision energy absorption capacity. It needs to be returned to the factory for replacement or professional repair.
Trace the source of the process: If such issues occur after repair, check whether the wrong welding fixtures were used or the "reverse deformation" process was not executed, resulting in excessive residual stress. If the vehicle is still within the warranty period or has just completed repair, please directly contact the brand-authorized service center for a special inspection of the high-voltage system. Do not disassemble the battery pack by yourself.
If you want to know more, keep reading the other articles on this site!
Please call us if you need such products.
Zhuo Meng Shanghai Auto Co., Ltd. is committed to selling MG&MAXUS auto parts welcome to buy.
