In the rapidly evolving industries of energy storage systems (ESS) and electric vehicles (EVs), the importance of thermal management cannot be overstated. Cooling plates play a pivotal role in ensuring the efficiency, safety, and longevity of high-power battery systems. However, the manufacturing process of these components is intricate, involving multiple advanced techniques to meet the specific requirements of different applications.
The first step in the manufacturing of cooling plates is material preparation. The choice of materials directly influences the performance, durability, and efficiency of the cooling plates.
This process involves cutting raw materials, typically metals like aluminium or copper, into the desired size and shape. Precision in shearing is essential to ensure that the cooling plate meets the specific dimensions required for its application.
In cases where complex cross-sectional shapes are needed, extrusion is employed. This process involves forcing the material through a die to create long sections with consistent profiles. Extruded materials are often used in the production of channels or fins within the cooling plate.
Aluminum offered a good balance between performance and cost. The extrusion process enabled the production of channels that optimized fluid dynamics, reducing the overall size and weight of the cooling plates.
The extrusion process, while effective, introduced complexities in maintaining tight tolerances during subsequent machining steps, which could potentially impact the flow uniformity within the channels (Yu et al., 2010).
For more intricate designs, laser cutting provides high precision and flexibility. This technique is particularly useful when creating complex flow channels or chambers within the cooling plate. Laser cutting ensures minimal material waste and high accuracy.
Flow channels or chambers are the heart of a cooling plate, allowing the coolant to circulate and dissipate heat effectively. The design and processing of these channels are crucial to the cooling plate’s performance.
This method involves shaping the metal by pressing it into a die. Stamping is often used to create the initial form of the flow channels. It is a cost-effective process, suitable for high-volume production.
For more precise or complex channel designs, machining is employed. This process involves removing material from the workpiece using cutting tools. Machining allows for greater control over the flow channel dimensions, ensuring optimal fluid dynamics within the cooling plate.
This technique is used to form channels by blowing high-pressure air into the material. The technique creates channels by blowing high-pressure air into the material. Pressure blowing allows for rapid formation of internal flow channels and is lightweight. The process is ideally suited for cooling panels with simple structures and low power heat exchange capabilities.
The next step involves the processing of connectors and accessories, such as inlets, outlets, and mounting beams. These components are essential for integrating the cooling plate into the larger system, ensuring proper fluid flow and mechanical stability.
The fabrication of inlets and outlets is critical for ensuring that the coolant enters and exits the cooling plate efficiently. These components must be precisely aligned and securely attached to prevent leaks and ensure consistent fluid flow.
Mounting beams are often added to provide structural support and facilitate the installation of the cooling plate within the system. These beams must be robust and accurately positioned to withstand mechanical stresses during operation.
Welding is a critical process in the manufacturing of cooling plates, as it ensures the structural integrity and durability of the final product. Several welding techniques are commonly used in cooling plate production:
A vacuum brazed liquid cooling plate refers to a type of water-cooled plate that is fabricated by processing two metal plates with internal channels and fin structures (typically folded or scraped fins) and then carefully sealing them within a vacuum chamber for heating.
This welding method, also known as gas shielded welding, relies on nitrogen gas protection during brazing. It’s tolerant of part inaccuracies up to 0.2mm and can use flux for gap filling. Gas shielded brazing enhances material flow, ensuring strong horizontal and vertical welds with a typical strength of about 30KG. Unlike vacuum and heating-dependent methods, it supports continuous high-efficiency production and allows for cost-effective rework post-failure
FSW is a solid-state welding process that joins materials without melting them. This technique is well-suited for producing high-strength, defect-free welds in cooling plates. FSW is often used for aluminium cooling plates due to its ability to create robust joints without compromising the material’s properties.
CMT is a variant of gas metal arc welding (GMAW) that offers precise control over the heat input. This technique minimizes thermal distortion, making it ideal for welding thin materials or delicate components in cooling plates.
Once the cooling plate is welded and assembled, surface treatment is applied to enhance its durability, corrosion resistance, and thermal performance.
Polishing is often used to create a smooth, reflective surface on the cooling plate. A polished surface can improve the plate’s heat transfer efficiency and reduce the risk of corrosion. Polishing also enhances the aesthetic appearance of the cooling plate, which can be important for visible components in consumer products.
To prevent electrical conductivity and improve thermal insulation, an insulation coating may be applied. This coating creates a protective barrier, ensuring that the cooling plate can operate safely within high-voltage environments, such as in EV battery packs.
The final step in the manufacturing process is testing and verification. This stage is crucial for ensuring that the cooling plate meets all performance and safety requirements before it is integrated into the final product.
Leak testing is performed to ensure that the cooling plate is completely sealed and that no coolant will escape during operation. This test is typically conducted using pressurized air or a liquid dye, allowing engineers to detect even the smallest leaks.
The cooling plate’s ability to dissipate heat effectively is tested under various operating conditions. This involves measuring the plate’s thermal conductivity, heat transfer coefficient, and overall cooling efficiency.
Mechanical tests, such as tensile strength and fatigue testing, are conducted to assess the cooling plate’s structural integrity. These tests ensure that the cooling plate can withstand the mechanical stresses it will encounter during operation.
Mechanical tests, such as tensile strength and fatigue testing, are conducted to assess the cooling plate’s structural integrity. These tests ensure that the cooling plate can withstand the mechanical stresses it will encounter during operation.
A Polish energy storage company faced a unique challenge in designing cooling plates for a large-scale ESS project. The system required highly efficient cooling to manage the thermal loads of densely packed battery cells. Standard flow channel designs were inadequate, necessitating a custom solution.
The engineering team employed a combination of stamping and precision machining to create a hybrid channel design. Stamping was used for the primary channel outlines, while machining refined the channels to meet the exacting requirements for coolant flow. This dual approach allowed for the creation of complex geometries that maximized heat transfer while minimizing pressure drops.
The hybrid approach enabled the creation of highly efficient cooling channels without the need for completely bespoke manufacturing processes, which would have significantly increased costs.
Integrating stamped and machined components required careful alignment and joining techniques to avoid potential leaks and ensure uniform coolant distribution.
A Hungarian manufacturer of heavy-duty electric vehicles faced challenges in producing cooling plates that could withstand the extreme thermal and mechanical stresses typical of their applications. Traditional welding methods led to issues with joint integrity, particularly under prolonged high-temperature conditions.
To address this, the manufacturer adopted Friction Stir Welding (FSW) for the assembly of their cooling plates. FSW, a solid-state process, provided superior joint strength and eliminated the defects commonly associated with fusion welding. The resulting cooling plates exhibited excellent performance in terms of thermal conductivity and mechanical durability, even under the most demanding conditions.
FSW produced joints with exceptional strength and fatigue resistance, crucial for heavy-duty applications. The absence of melting in the process also preserved the material properties, leading to a more reliable cooling plate.
The adoption of FSW required significant investment in specialized equipment and training, which increased the initial production costs. However, these costs were justified by the enhanced performance and reduced failure rates in the final product.
The use of FSW in this case underscores the importance of selecting appropriate welding techniques based on the application’s specific requirements. For high-stress environments, the choice of welding method can significantly influence the long-term reliability and performance of cooling plates.
A Czech ESS manufacturer needed to protect its cooling plates from the harsh environmental conditions typical of outdoor installations. The challenge was to apply a surface treatment that would provide both corrosion resistance and electrical insulation without compromising the cooling efficiency.
The solution involved applying a dual-layer coating system. The first layer was an anodic oxidation coating, providing excellent corrosion resistance. The second layer was an insulation coating, specifically designed to prevent electrical conduction while maintaining thermal conductivity. This combination ensured that the cooling plates remained effective and durable throughout their operational life.
The dual-layer coating provided comprehensive protection, extending the lifespan of the cooling plates and ensuring safe operation in high-voltage environments. The approach also preserved the cooling efficiency, a critical factor in ESS applications.
The application of multiple coatings required precise control over the thickness and uniformity of each layer. Any deviations could lead to hotspots or reduced cooling performance, necessitating rigorous quality assurance protocols.
This case highlights the critical role of surface treatment in enhancing the durability and efficiency of cooling plates, especially in challenging environments. By carefully selecting and applying the right coatings, manufacturers can significantly improve the performance and reliability of their products.
A Polish startup specializing in electric vehicles faced significant challenges in ensuring the reliability of its cooling plates during the development of its first prototype. Given the critical role of thermal management in EV performance, the company implemented a rigorous testing and verification process.
The testing regime included extensive leak testing, thermal performance evaluation, and mechanical stress testing. The leak testing involved both air pressure and dye penetrant methods to detect any potential leaks at the earliest stages. Thermal performance was assessed under various load conditions, simulating real-world driving scenarios. Mechanical testing focused on the cooling plate’s ability to withstand vibrations and impacts typical of automotive environments.
The comprehensive testing regime provided the startup with valuable data, allowing for iterative improvements in the cooling plate design. Early detection of potential issues helped avoid costly recalls and performance failures in the field.
The extensive testing process added time and cost to the development cycle, but these were deemed necessary investments to ensure product quality and customer satisfaction.
The approach taken by this Polish startup emphasizes the importance of thorough testing and verification in the development of cooling plates, particularly for new entrants in the EV market. Rigorous testing not only ensures product reliability but also builds trust with customers and stakeholders.
The manufacturing of cooling plates is a complex and precise process, involving multiple steps to ensure the final product meets the high standards required in industries like energy storage and electric vehicles. From material preparation to testing and verification, each step is crucial in producing a cooling plate that delivers optimal performance, durability, and reliability.
For professionals understanding this process can help in making informed decisions when selecting suppliers or evaluating cooling plate technologies. Whether you’re a mechanical engineer, procurement manager, or involved in the high-voltage battery industry, this guide provides the insights needed to navigate the complexities of cooling plate manufacturing and make strategic choices for your projects.
I've worked in battery thermal management for over 5 years, handling lots of international projects. If you're curious about battery liquid cooling products or services, feel free to ask me any questions!
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