What is a Battery Cooling Plate? Composition and Requirements

Battery thermal management systems are key technologies to address issues related to battery heat generation, ensuring the performance, safety, and lifespan of power batteries.

The main functions of the thermal management system include:

1.?Effective heat dissipation when battery temperatures are high to prevent thermal runaway incidents.

2.?Preheating to raise the temperature of the batteries at low temperatures, ensuring charging and discharging performance and safety in cold conditions.

3.?Reducing temperature differences within the battery pack to prevent the formation of local hot spots, slowing down the degradation of the battery pack. In some special cases, traditional air cooling is no longer sufficient, and liquid cooling systems must be adopted. Excellent liquid cooling plate technology and related pipeline connection technology ensure operation at the appropriate temperature.

The liquid cooling plate is the core component of the battery thermal management liquid cooling module. In electric vehicles, the cooling system mainly includes cooling for the drive motor, vehicle controller, and DC, as well as for the power battery and on-board charger. Currently, the main power batteries in electric vehicles are lithium-ion batteries, which are sensitive to temperature changes. The temperature environment within the battery pack has a significant impact on the reliability, lifespan, and performance of the cells, making battery thermal management an essential safeguard for the operation of new energy vehicles. The liquid cooling plate is one of the most critical components in the battery pack’s liquid cooling system. Excess heat generated by the battery is transferred through contact with the surface of the plate-shaped aluminum device, which is then taken away by the coolant flowing through the internal channels of the device. This plate-shaped aluminum device is the liquid cooling plate.

The battery cooling plate is a key component in the EV thermal management system. This article will provide a detailed introduction to its structure, material selection, technical requirements, and future development trends.

A.?Structure of the Battery Cooling Plate

The structure of a battery cooling plate typically includes the following key parts:

Base Plate: It is the main body of the cooling plate, usually made of high thermal conductivity materials such as aluminum or copper, to provide good thermal contact with the battery surface.

Flow Channels: They are the paths through which the coolant flows within the cooling plate.

Extended Surfaces or Fins: To increase the contact area with the coolant and improve heat exchange efficiency, fins or other extended surfaces may be designed on the cooling plate.

Inlets and Outlets: There are specific inlets and outlets on the cooling plate for the entry and exit of the coolant, and the design of these parts needs to ensure uniform fluid flow and minimal pressure loss.

Connectors: They are used to secure the cooling plate to the battery pack while ensuring good contact between the cooling plate and the battery.

Seals: They are used to ensure the sealing between the cooling plate and the battery, as well as between various parts of the cooling plate, to prevent coolant leakage.

Sensor Integration: In some designs, the cooling plate may be integrated with temperature sensors to monitor the temperature of the battery and coolant, providing feedback for the thermal management system.

B.?Common Materials for Battery Cooling Plates

Aluminum Alloy: It is a lightweight, high-strength material with good thermal conductivity, widely used in automotive electronic radiators, air conditioning equipment, and battery cooling plates. Aluminum alloy has good heat dissipation performance, is lightweight, and relatively inexpensive, suitable for mass production. Therefore, aluminum alloy is the most commonly used material for battery cooling plates and represents a mature technology.

Copper Alloy: It is a corrosion-resistant material with good thermal and mechanical properties. Compared to aluminum alloy, copper alloy is more expensive but has better thermal conductivity and higher strength. In high-power batteries, copper alloy used as a cooling plate material can improve heat dissipation and extend the battery life.

Carbon Fiber: It is a high-strength, lightweight, and high-temperature-resistant material with excellent thermal and electrical conductivity. In electric vehicles, using carbon fiber to make cooling plates can effectively reduce the operating temperature of the battery and improve its cycle life. However, due to the high cost of carbon fiber, it is still in the research phase.

Ceramic: It is a chemically stable, thermally conductive, corrosion-resistant, and wear-resistant material. Ceramic materials have good performance stability and strength in high-temperature environments. In battery cooling devices, ceramic’s thermal and chemical stability stand out, but its production cost is high, and further research is needed for increased use.

Overall, aluminum alloy and copper alloy are the most commonly used materials for battery cooling plates, with mature processes, excellent heat dissipation effects, and cost-effectiveness. Carbon fiber and ceramic have excellent performance but are more expensive, and their scope of application needs further expansion. When selecting a battery cooling plate, it is necessary to choose the appropriate material based on actual application needs.

C.?Technical Quality Requirements for Liquid Cooling Plates

High Heat Dissipation Capacity: The heat dissipation capacity of a liquid cooling plate refers to its ability to absorb heat. The greater the heat dissipation capacity, the more heat the liquid cooling plate can absorb, thus cooling electronic devices more effectively.

High Reliability, Ensuring Plate Sealing: The reliability of a liquid cooling plate refers to its ability to function normally over a long period of use. The liquid cooling plate must be able to withstand high pressure, high flow rates, and high temperatures, and resist corrosion and leaks.

Precise Heat Dissipation Design: The heat dissipation design of a liquid cooling plate needs to be precise to ensure that heat is absorbed uniformly and transferred to the coolant, avoiding excessive temperature differences within the system.

Strict Control of Plate Weight: The weight of the liquid cooling plate needs to be strictly controlled to avoid increasing the weight and volume of electronic devices.

Some factors that affect the quality of liquid cooling technology include:

Materials: The materials of the liquid cooling plate need to have good thermal conductivity and corrosion resistance. Common materials for liquid cooling plates include copper, aluminum, stainless steel, etc.

Structure: The structure of the liquid cooling plate needs to effectively absorb heat and transfer it to the coolant. Common structures include microchannel structures, pin structures, etc.

Process: The process of the liquid cooling plate needs to be refined to ensure sealing and reliability. Common processes for liquid cooling plates include welding, brazing, bonding, etc.

Liquid cooling system equipment should undergo relevant tests before leaving the factory and meet national and industry standards, as well as design requirements, including appearance quality, performance, water quality performance, environmental adaptability, working methods, and other aspects of testing and verification.

D.?Types of Battery Cooling Plates

Based on the cooling method, battery cooling plates can be divided into the following categories:

Air-cooled Battery Cooling Plates: Air-cooled battery cooling plates use fans to blow air over the battery surface to remove heat. They are simple in structure, and low in cost, but have lower cooling efficiency, and are suitable for low-power battery applications.

Liquid-cooled Battery Cooling Plates: Liquid-cooled battery cooling plates use circulating coolant to absorb heat generated by the batteries. They have high cooling efficiency and are suitable for high-power battery applications.

Phase Change Material Battery Cooling Plates: Phase change material battery cooling plates use the heat absorption and release characteristics of phase change materials to absorb and release heat generated by the batteries. They have good heat dissipation effects and temperature uniformity but are more expensive.

The production process of liquid cooling plates is much more complex than that of air-cooled heat sinks. The main processes of liquid cooling plate production technology include raw material stamping, cleaning, solder flux application, riveting, brazing, inspection, and sealing, with common production technologies including embedded tube process, profile + welding, machine processing + welding, and die casting + welding.

E.?Future Development Trends of Battery Cooling Plates

As the power of electric vehicle batteries continues to increase, the technology of battery cooling plates will also continue to develop. In the future, it may develop in the following directions:

Integrated Design: With the development of electric vehicle technology, the design of battery cooling plates tends to be more closely integrated with the battery pack to improve space utilization and thermal management efficiency.

Diversified Cooling Methods: The cooling methods of battery cooling plates will become more diversified, including bottom cooling, side cooling, and multi-face cooling, to adapt to the needs of different battery designs and layouts.

Material Innovation: To improve cooling efficiency and reduce costs, there may be breakthroughs in the materials of battery cooling plates, such as using lighter, better thermally conductive materials or composite materials.

Intelligent Control: Battery cooling plates will be more deeply integrated with the battery management system to achieve intelligent temperature control, adapting to different working conditions and driving modes.

Improved Heat Dissipation Efficiency: With the increase in battery energy density, the heat generation per unit volume increases, and battery cooling plates need to have higher heat dissipation efficiency to meet the cooling requirements.

Market Size Growth: With the rapid growth of the new energy vehicle market, the market demand for battery cooling plates is expected to continue to expand, especially in passenger cars, commercial vehicles, and energy storage fields.

Battery cooling plates are a critical technology for ensuring the safe and efficient operation of electric vehicle batteries. As technology continues to advance and market demand grows, battery cooling plates will play an increasingly vital role in the field of thermal management for electric vehicles.