Liquid Cold Plate
What is Liquid Cold Plate?
A Liquid Cold Plate is an advanced heat exchanger that uses circulating liquid coolant to efficiently cool high-power electronics and industrial systems. Made from conductive metals like aluminum or copper, these plates feature internal microchannels that allow coolant (water, glycol, or dielectric fluid) to absorb heat from components through direct contact. This method far outperforms air cooling, offering 25-100x greater thermal conductivity—critical for EVs, data centers, power electronics, and aerospace applications. Cold plates operate in closed-loop systems: heat transfers from the component to the plate, the coolant removes it, and a radiator expels it before recirculation. Benefits include compact designs (replacing bulky heatsinks), silent operation (no fans), and scalability for extreme heat loads (kW+). They’re widely used in EV battery packs (preventing overheating), servers (CPU/GPU cooling), IGBT modules (industrial inverters), and medical lasers. Selection depends on material (copper for high conductivity, aluminum for lightweight), coolant type, and channel design (microchannels for precision, tube-embedded for durability). With unmatched efficiency and reliability, liquid cold plates are ideal for applications where traditional cooling fails, ensuring optimal performance and longevity in demanding environments.
Types of Liquid Cold Plate
Copper&Stainless Tube Liquid Cold Plate
1. Process: The tube can be round or flat (D-shaped). Bend the copper or stainless steel tube into the desired flow path. Use a copper plate or aluminum plate with good thermal conductivity (commonly, copper tube’s high thermal conductivity compensates for the shortcomings of aluminum base plates) as the base plate. Machine grooves in the base plate to match the tube shape. Insert the bent copper or stainless steel tube into the grooves in the base plate.
2. Copper Tube Water-Cooling Plate:
Advantages: Extremely high thermal conductivity, excellent heat dissipation, good ductility, and machinability;
Disadvantages: Relatively high raw material cost, relatively heavy weight, and average corrosion resistance.
3. Stainless Steel Tube Water-Cooling Plate:
Advantages: Excellent corrosion resistance, high strength and rigidity, and good pressure resistance;
Disadvantages: Poor thermal conductivity and difficult machining.
FSW (friction stir welding) liquid cold plates
Revolutionize Cooling with Friction Stir Welded (FSW) Liquid Cold Plates!
1. Process: The substrate and flow channel are prepared (typically made of a thermally conductive metal such as aluminum or copper alloy). High-speed rotation or linear vibration friction is applied to the substrate and flow channel interface, causing high-temperature plastic deformation. Solid-state metallurgical bonding is achieved under pressure (no solder required), forming a sealed flow channel.
2. Advantages: The metallurgical bond layer has extremely low thermal resistance, significantly improving thermal conductivity compared to brazing or gluing. Weld strength is ≥ 90% of the parent metal, with high pressure resistance and thermal fatigue resistance. Solid-state welding eliminates flux residue and is compatible with high-purity coolants. It supports dissimilar metal welding (e.g., aluminum substrate + copper flow channel).
3. Disadvantages: Large equipment investment, and single-piece processing time exceeds traditional brazing. The flow channel must be a continuous straight line or simple curve, making complex 3D paths difficult to achieve.
Vacuum Brazing / Welding Liquid Cold Plate
Ultra-Reliable Cooling – Vacuum Brazed/Welded Liquid Cold Plates for Extreme Thermal Performance!
1. Process:
Base material: High-purity aluminum alloy (6061/3003) or copper alloy (C1100), surface roughness ≤ Ra 1.6μm.
Pre-place a brazing foil (0.1-0.2mm thick) between the base and cover plates for precision assembly. Support columns (spacing ≤5mm) are added to the flow channel area to prevent collapse.
2. Advantages
Zero-oxidation metallurgical bonding: The vacuum environment eliminates oxide formation, and the weld bond strength is ≥85% of the parent metal (conventional brazing only 60-70%).
Ultimate flow channel precision: Microchannels as small as 0.05mm can be achieved (due to excellent brazing filler metal flowability), and the flow channel wall thickness can be as thin as 0.3mm.
Ultra-high sealing: The entire weld is porosity-free, with a burst pressure >15MPa (30% higher than conventional brazing).
Material property preservation: No softening of the heat-affected zone of the substrate (copper base hardness loss <5 HV). No Corrosion Risk: No flux is required, completely eliminating intergranular corrosion caused by residual Cl⁻.
3. Disadvantages
Extremely High Manufacturing Cost: Equipment investment >$2 million, and energy costs per piece are 3-5 times higher than conventional brazing.
Long Production Cycle: Vacuuming and step-by-step temperature ramping take 4-8 hours per furnace.
Strict Design Constraints: Assembly clearances must be controlled within 0.05-0.15mm (exceeding this range will result in brazing filler metal overflow or cold solder joints).
Large Size Limitation: Commercial vacuum furnaces typically have an effective volume of <2m³ (automotive battery cold plates require segmented welding).
Solder Paste Welded Liquid Cold Plate
Process:
Copper substrate (nickel-plated for oxidation protection) or aluminum substrate (electroless nickel plating required). Machine grooves or etch microchannels (depth 0.5-3mm). Screen-print SAC305 solder paste (Sn96.5/Ag3.0/Cu0.5) to the soldering area, thickness 0.1-0.15mm. Apply 0.5-1kg/cm² of pressure to the copper tube/aluminum cover to ensure proper adhesion. Peak temperature 240-250°C (copper) or 220-230°C (aluminum). Fill the solder joint with liquid solder paste (time <90 seconds). Remove flux residue with water washing, and X-ray to check voiding (requires <15%).
Advantages:
Ultra-low thermal budget: Soldering temperature <250°C (much lower than brazing temperatures of 600°C+), avoiding annealing and softening of the substrate (hardness retention >98% for copper). High-Precision Adaptation: Stencil printing offers positioning accuracy of ±0.05mm, making it suitable for cold plate manufacturing with microchannels (width ≥ 0.3mm).
Cost-Efficient: The process is compatible with SMT production lines, with a cycle time of less than 5 minutes per part (compared to several hours for soldering).
Repairability: The cover can be removed and replaced with localized heating, with repair costs 1/10th that of soldering.
Disadvantages:
Thermal reliability deficit: Solder paste thermal conductivity is approximately 60W/mK (only 1/6 that of copper), and the interfacial thermal resistance is as high as 0.1-0.3 cm²K/W.
Insufficient Mechanical Strength: The weld shear strength is less than 30MPa (aluminum brazing >80MPa), and it cannot withstand high pressures (burst pressure <3MPa).
Corrosion Failure Risk: The electrochemical potential difference (Cu-Sn ≈ 0.48V) triggers galvanic corrosion, requiring strict coolant pH control (6.5-7.5). Low temperature limit: long-term operating temperature ≤ 80℃ (SnAgCu eutectic melting point 217℃), tin whiskers are easily generated after thermal cycling, leading to short circuits.
FAQ
1. What is the production cycle for a water-cooling plate?
The sample cycle for a water-cooling plate is 12-15 days, and the mass production cycle is 20-25 days.
2. Does the water-cooling plate require mold fees?
Pressed tube water-cooling plates, welded water-cooling plates, and friction welded water-cooling plates do not require mold fees.
3. Can the water-cooling plate be tested?
Water-cooling plates can be tested for leaks using a pressure gauge (MPa).
Applications
