Industrial & Commercial Energy Storage: Liquid Cooling – Cold Plate vs. Immersion

Liquid Cooling Systems: Enhancing Efficiency and Battery Life

Liquid cooling systems offer high heat dissipation efficiency and minimize temperature differences between battery clusters, significantly improving battery lifespan and overall lifecycle economics. The enhanced cooling capability directly leads to a substantial increase in energy density for energy storage systems. With advanced liquid cooling technology, the capacity of a single unit equivalent to a traditional 40-foot container can increase from 2.5MWh to 6.7MWh. Additionally, the footprint of energy storage stations with the same capacity can be reduced by over 50%. For future large-scale energy storage stations exceeding 100MWh, the land-saving benefits will be even more pronounced.

Liquid cooling can be categorized into two types based on contact methods: direct contact and indirect contact.

Indirect contact liquid cooling is commonly represented by cold plate cooling.

Direct contact liquid cooling is typically achieved through immersion cooling technology.

1. Cold Plate Cooling (Indirect Liquid Cooling)

In this method, the heat-generating components and the cooling medium do not directly contact each other. Cold plate cooling dissipates heat by directly contacting a liquid-filled cold plate or transferring heat to the cold plate via thermal conductive components. The heat is then carried away by the liquid circulating inside the cold plate.
Liquid cold plates are critical components for battery thermal management, often requiring joint development and design with customers to ensure compatibility with specific battery systems. Based on manufacturing processes, cold plates can be classified into blow-molded, brazed, and harmonica types.

Blow-molded plates are cost-effective and highly efficient, making them suitable for commercial vehicles and energy storage systems.

Brazed plates excel in sealing, weight, precision, and heat dissipation performance.

Production Process:

The manufacturing process for cold plates includes raw material stamping, cleaning, flux coating, riveting, brazing, testing, and sealing. Common production techniques include embedded tube, profile + welding, machining + welding, and die-casting + welding.

2. Immersion Cooling (Direct Liquid Cooling)

This method involves fully submerging battery cells in an insulating, non-toxic, and heat-dissipating liquid (a compound similar to “oil”). The liquid directly contacts the cells to dissipate heat, achieving efficient thermal management. The system is supported by oil circulation and refrigeration systems, using cooling oil as the medium to quickly and effectively remove heat, ensuring the cells operate within the optimal temperature range.

Since the immersion liquid contacts the cells comprehensively, it better controls temperature differences. Additionally, when non-oil-based coolants are used, the liquid itself can act as a fire suppressant, integrating thermal management and fire safety.

Types of Immersion Cooling Systems:

Immersion cooling systems can be divided into three main types: water-based, oil-based, and fluorine-based.

Advantages of Immersion Cooling

Superior Thermal Management: Batteries are submerged in insulating coolant, ensuring excellent heat dissipation and zero safety risks.

Optimal Thermal Solution: Maintains battery temperature differences below 2°C.

Adaptability: Suitable for harsh environments, including high/low temperatures and high altitudes.

Space Efficiency: No air ducts required, maximizing space utilization and system energy density.

Reduced Failure Rates: No fans or moving parts, lowering failure rates and secondary losses.

Scalability: Multiple cabinets can be freely combined to meet varying capacity requirements.