In 2021, a company located in Moss Landing, Monterey County, California, experienced an overheating issue with their 300 MW/1,200 MWh energy storage system on September 4th, which remains offline. Despite the response from the North County Fire Protection District, the overheating was contained and controlled without external assistance. However, the 300 MW unit remains offline for an uncertain duration, causing widespread power outages in the area and posing various safety risks. Additionally, some energy storage systems have experienced major disasters such as leaks and explosions due to thermal runaway.

Improper Temperature Control in Energy Storage Batteries Can Lead to Thermal Runaway

The past decade can indeed be referred to as the "Golden Decade" of flourishing development for energy storage systems. Global demand for energy storage has surged, and installations of these systems have proliferated worldwide like mushrooms after rain. However, a major challenge in the development of battery storage systems lies in effectively managing the heat generated during the charging and discharging processes.

If the heat generated by the batteries exceeds a certain limit, it can potentially lead to:

• If the batteries are not operated at the appropriate temperature, it can lead to a decline in battery performance, a significant reduction in lifespan, and may even result in damage to battery components and system shutdown.

• In severe cases, overheating of the batteries can cause them to reach a point where they cannot withstand the temperature, resulting in explosions and fires, leading to unimaginable losses. As battery storage extends onto the grid to supplement and support renewable energy generation, ensuring the safety of the grid remains a critical concern.

Energy storage on fire at Victorian Big Battery, Australia. Image: Fire Rescue Victoria

In the safety of large-scale commercial energy storage systems, the issue of lithium battery thermal runaway is of utmost importance. Essentially, this occurs when a fault causes excessive heat buildup within the battery. This can generate significant heat and trigger a self-accelerating reaction, potentially leading to fires or explosions. There are various reasons for thermal runaway, including internal defects in the batteries, malfunctions in the battery management system, and environmental contamination, among others.

To address this challenge, the lithium battery manufacturer MeritSun has invested significant financial and human resources into researching how to reduce the occurrence of thermal runaway in lithium batteries and minimize the losses associated with it. Currently, in the energy storage industry, air cooling (wind cooling) and liquid cooling are the two most common cooling mechanisms. So, how does one decide between air cooling and liquid cooling?

Air Cooling vs. Liquid Cooling: How to Choose？

Air Cooling:

An air cooling system utilizes air as the cooling medium, exchanging heat through convection to lower the temperature of the battery.

Air cooling systems have the advantages of simple construction, easy maintenance, and low cost. Air cooling involves using fans or blowers to circulate air around the battery pack for heat dissipation.

In an air cooling system, the battery pack is usually equipped with a radiator that absorbs the heat from the batteries. Subsequently, fans or blowers blow the surrounding air over the radiator to dissipate the heat.

The limitations of air cooling systems are primarily seen in their limited cooling capacity, especially in high-temperature environments, where they may not provide an equally effective cooling effect compared to liquid cooling. Additionally, this type of system typically requires fans for cooling, generating noise, and occupying additional space within the device or system, making it less suitable for noise-sensitive or space-constrained scenarios.

The cooling efficiency is also lower, making it challenging to achieve uniform battery cooling and maintain a consistent temperature distribution, potentially leading to overheating or overcooling in certain areas.

Furthermore, in situations with high heat generation, such as high-performance lithium-ion batteries, relying solely on air cooling may not effectively lower the temperature, resulting in increased operating temperatures that could impact battery performance and lifespan.

However, air has lower specific heat capacity and thermal conductivity, making it less suitable for high heat generation applications. Currently, it is more commonly used in:

• Consumer electronic products such as smartphones, laptops, and tablets.

• Low-power electric cars and electric bicycles.

• Small-scale energy storage systems.

Liquid Cooling:

A liquid cooling system utilizes a liquid as the cooling medium, dissipating the heat generated by the battery through convective heat exchange. The structure of a liquid cooling system typically involves one or multiple curved water pipes embedded within the casing. During operation, the inlet and outlet of the pipes are connected to an external circulating water system. The circulating water system delivers cold water to the pipes, which then flows through them. The cold water flowing along the pipes absorbs heat from the walls, which is then emitted by the batteries. Subsequently, the cold water warms up, and the heated water returns to the circulating water system from the pipe outlet.

Currently, China's leading lithium battery manufacturer, MeritSun, employs advanced liquid cooling systems in their commercial and industrial energy storage series to regulate the temperature during the operation of large-scale energy storage systems. This is because liquid cooling systems offer several advantages:

• Improved Heat Dissipation and Reduced Noise:

  Liquid cooling systems typically dissipate heat more effectively, leading to better temperature control and heat management. Additionally, liquid cooling systems generally generate less noise compared to air cooling fans.

  
  

• Enhanced Cooling Capacity and Uniform Cooling Distribution: 

  Liquid cooling can handle higher heat loads while maintaining lower operating temperatures. Liquid cooling systems provide a more uniform cooling distribution between battery units.

  
  

• Precise Temperature Control: 

  Liquid-cooled energy storage systems directly dissipate heat from the battery cells through the coolant, allowing for precise temperature control unaffected by external conditions.

  
  

• Safety, Cost-effectiveness, and Suitable for High-Capacity Energy Storage: 

  Liquid cooling systems are not only safer and more cost-effective but also more suitable for high-capacity energy storage. Compared to traditional air-cooled containers, liquid cooling systems can increase energy density by 100%, saving over 40% of the floor space.

  
  

• Energy Efficiency: 

  Liquid cooling systems can save approximately 30% more energy compared to air cooling systems. Simultaneously, they maintain lower cell temperatures and better temperature uniformity, effectively extending battery life, reducing economic input, and shortening the payback period.

MeritSun's Advanced Liquid Cooling in Large-Scale Energy Storage

As energy storage experts with 24 years of experience in lithium battery production and manufacturing, MeritSun has dedicated decades to researching high and low-temperature control technology for energy storage systems. Currently, all of MeritSun's large-scale energy storage systems utilize cutting-edge liquid cooling technology.

In fact, considering the entire system, designing an air cooling system would be simpler and more cost-effective. However, to achieve better performance and ensure the safety of the cabinets in the energy storage system, MeritSun opts for a more sophisticated modular design with a liquid cooling system. All components are pre-assembled and tested in the factory, eliminating the need for on-site installation and debugging. This creates an efficient, stable installation process, reducing costs and project timelines, ensuring system quality and performance, optimizing energy dissipation efficiency, and enhancing overall operational efficiency, and reliability.

While liquid cooling systems for energy storage equipment, especially lithium batteries, are relatively more complex compared to air cooling systems and require additional components such as pumps, radiators, and coolant circulation systems, which may increase space and weight, their advantages in lithium battery energy storage equipment are undeniable.

MeritSun's liquid cooling system effectively absorbs and dissipates the heat generated by the batteries through a high thermal conductivity liquid, achieving higher heat dissipation efficiency, maintaining a stable temperature within the battery pack, and improving energy storage efficiency. The liquid cooling system allows precise control of the coolant, ensuring safe operation and a long lifespan for the battery pack. This precise control is crucial for the cycling stability and performance optimization of lithium-ion batteries. Despite potential cost increases, the outstanding performance of the liquid cooling system makes it the preferred choice for MeritSun's commercial lithium-ion battery energy storage equipment, providing reliable support for a dependable and efficient energy storage system.

Partner with MeritSun for Advancing Safe, Stable, and Sustainable Green Energy Solutions

In conclusion, when considering the selection of an appropriate cooling system for an energy storage system, performance, safety, and lifespan are crucial factors. Careful consideration of the system's requirements and limitations is essential to making informed decisions regarding the cooling system to be used. As a dominant trend in the industry, liquid cooling systems are undoubtedly the preferred choice for high-performance and high-safety energy storage needs.

MeritSun, as a leading lithium battery manufacturer in the industry, employs reliable liquid cooling systems in their commercial and industrial energy storage cabinet products. If you are interested in learning more about MeritSun's commercial and industrial energy storage products and liquid cooling system services, we welcome you to visit our official website at www.meritsunpower.com to gather more information.

By George

MeritSun Power Limited

export-10@MeritSunpower.com

MeritSun was founded in 1999, we have 24 years of professional experience in energy and integrated solution services. We have 100+R&D teams,1368 employees,48 fully automatic production lines, and a 150,000 square meters factory, become the industry pioneers in battery suppliers through effective management.