New energy vehicles have more complex thermal management needs. They are harder for batteries, motors, and electronics than traditional vehicles. In this article, we’ll delve into the specific challenges of battery thermal management. Currently, mainstream technical solutions include air-cooling, liquid-cooling, and direct-cooling. The cost of liquid-cooled plates is decreasing. Battery safety and performance standards are rising. As a result, liquid cooling has become the main technology for battery thermal management. Cold Plate & Welding: Thermal Management Battery thermal management must address three key challenges: dissipating heat from and heating battery cells, maintaining temperature balance within the battery pack, and managing thermal expansion and contraction of liquid-cooled components. An effective cooling system is crucial for new energy vehicles. It must, for example, use aluminum alloy liquid-cooled radiators to meet these challenges.
Table of Contents
Cold Plate & Welding: Challenges in Thermal Management
Liquid Cold Plates are the main method for managing battery heat in new energy vehicles. However, they face several challenges in use. Here are the key aspects:
Design Complexity: Designers must know fluid dynamics, materials science, and heat transfer. They need this to navigate complex design requirements. For instance, bad design may lead to a 30% increase in coolant flow resistance. This increase would hurt cooling efficiency.
Manufacturing Complexity: Machining flow paths must be precise. Using high-quality materials raises costs. Employing high-precision machining techniques can escalate manufacturing costs by up to 20%.
Maintenance Difficulty: Maintenance requires special equipment and staff. This is a challenge for some users. They may find it too expensive.
Leakage Risk: We need strong measures to stop coolant leaks. They can cause big damage to the battery. This shows the need for professional protection rules.
Cooling Effect: Many factors affect how well cooling works. These include flow rate, pressure drop, and temperature changes. They make cooling prone to instability. It needs careful monitoring and adjustment.
Liquid Cooling Plate Applications
There are currently four main uses for liquid-cooled panels: power and energy storage battery packs, high heat flow density liquid-cooled components, and new liquid-cooled components.
Power Battery Packs: Liquid-cooled plates are widely used in power battery packs. They manage the heat of high-capacity batteries in new energy vehicles. This application ensures consistent performance and safety under various operating conditions.
Energy Storage Battery Packs: The panels are vital. They keep batteries at the best temperature. Batteries are in energy storage systems, which are crucial for renewable energy and grid stability.
High Heat Flow Density Liquid-Cooled Heat Transfer Components: This category includes components that handle high heat, such as inverter heat exchangers and IGBT heat exchangers. It also includes photovoltaic panel liquid cooling systems. These applications are critical in high-performance electronics and renewable energy systems.
New Liquid-Cooled Heat Transfer Components: Liquid-cooled panels are being used in new ways. This includes freeze dryer and chiller heat exchange components. These parts are crucial for industrial processes. They need precise temperature control and efficient heat dissipation.
Liquid-cooled plates can be broadly divided into four categories according to the type of process:
Vacuum Brazing Cold Plate (Aluminum Vacuum Brazing Cold Plate): This method has great heat performance. It is also strong. So, it is ideal for high-reliability uses.
Friction Stir Welding Type Water-Cooled Plate (FSW Cold Plate): It is known for its strong welds and reliability. This type is good for applications where toughness is vital.
Exposed Tube Cold Plate: This design allows direct contact between the coolant and the tubes. It offers efficient heat transfer and is easy to make.
Aluminum/Copper Plate Long Hole Drilled: This type has long drilled holes in aluminum or copper plates. It offers a low-cost solution with good heat conduction and strength.
Why choose aluminum for liquid-cooled Plates?
There are many reasons to select aluminum. It is the best material for liquid-cooled panels.
High Thermal Conductivity: Aluminum has great thermal conductivity. It beats stainless steel by over threefold and copper’s too. Aluminum has superior thermal conductivity. It lets liquid-cooled panels made from it dissipate heat more efficiently, even at the same mass.
Lightweight: Aluminum is much lighter than other common metals. So, liquid cooling panels made from aluminum are lighter than those made from other materials. This lightweight characteristic contributes to overall vehicle weight reduction and enhanced energy efficiency.
Corrosion Resistance: Aluminum resists corrosion well. This allows panels to withstand exposure to liquid. This corrosion resistance ensures the cooling system lasts. It is reliable, even in harsh conditions.
Ease of Processing: Aluminum is renowned for its ease of processing compared to other metals. It can be easily machined, formed, and fabricated into complex shapes. This helps in making intricate liquid-cooled panels.
But, it’s important to acknowledge that aluminum has drawbacks. This is especially true in welding:
Lower Melting Point: Aluminum has a lower melting point than other metals. This causes a larger heat-affected zone during welding. This can lead to the formation of pores and cracks, compromising weld quality and structural integrity.
Thicker Oxide Film: Aluminum tends to form a thick oxide film on its surface. This requires pretreatment to ensure good adhesion and weld quality.
Higher Thermal Expansion Coefficient: Aluminum has a higher expansion coefficient. This leads to more thermal deformation during welding. Specialized techniques are required to control welding deformation and maintain dimensional stability.
Despite these challenges. But, the many benefits of aluminum make it a preferred choice for liquid-cooled panels. It strikes a balance between performance, durability, and ease of manufacturing.
Challenges in Welding Liquid-Cooled Plates
When the welding quality of liquid cooling plates does not meet standards, several problems may arise:
Poor Quality of the Weld: Weak strength at the weld can lead to later cracking and leakage. This compromises the structural integrity and safety of the cooling system.
Reduced Heat Dissipation: Bad welding creates too much heat after welding. This harms how well the cooling plate can get rid of the heat. This can lead to overheating issues and decreased performance of the system.
Decreased Thermal Conductivity: Bad welding lowers the aluminum’s thermal conductivity. This hinders heat transfer in the cooling plate This undermines the overall cooling effectiveness of the system.
Influence on Material Performance: Poor welding can cause material deformation. It can also cause grain growth and related problems. These issues hurt the plate’s strength and performance. This compromises the durability and reliability of the cooling system.
Currently, there are three mainstream welding processes for liquid-cooled plates:
Friction Stir Welding: This method offers high weld strength and reliability, allowing for replenishment. However, it may lead to profile welding issues or cold plate tampering.
Gas Shielded Welding: This technique is cost-effective and offers good pressure resistance. However, it needs added materials and heat treatment. This increases process complexity.
Vacuum Brazing Welding: It is known for its high-quality weld seams and simplicity. The process ensures good weld integrity. However, it comes with higher costs compared to other methods.
To address these challenges and improve the plates, Trumonytechs’s staff focuses on:
Selecting Appropriate Welding Method: Choose the best welding method based on the application’s needs and the materials.
Strictly Controlling Welding Parameters: We must control welding parameters precisely. These include temperature, pressure, and welding speed. We do this to get the best results.
Testing Weld Seam Quality: We will test the weld seams thoroughly. This will find defects or inconsistencies. It will also ensure they meet quality standards.
Selecting Suitable Filler Material and Shielding Gas: We use high-quality filler materials and shielding gases. They improve weld quality and integrity. This makes the cooling system work better.
Weld seam qualification by trumonytechs Technology
At the end of the liquid-cooled plate welding process, the following are some of the common inspection methods used in the industry:
Visual inspection method: You judge weld quality by looking at the weld’s appearance. This includes weld integrity, uniformity, cracks, slagging, and porosity.
Radiographic testing: X-ray or gamma radiation is used for fluoroscopy or photography of the weld. It is used to find the internal cracks, porosity, etc. of the weld.
Ultrasonic detection: the use of ultrasonic waves on the weld seam
Magnetic particle detection: They apply magnetic powder after welding. They detect defects by watching the powder’s distribution in the weld.
Eddy current detection: using the principle of eddy current induction to carry out the detection.
The staff of Trumonytechs will test the weld seam quality after each weld. They will pick the method based on the actual situation. If needed, they will use a mix of methods to ensure the quality of the liquid-cooled plate.
