Should energy storage systems be air-cooled or liquid-cooled?

1. What is an Air-Cooled Battery Energy Storage Pack?

An air-cooled battery energy storage pack is an energy storage system module that uses air as the primary heat dissipation medium, controlling battery temperature through airflow driven by a fan. Its simple structure, low cost, and ease of maintenance have made it a common cooling method in commercial and industrial energy storage, small-scale energy storage devices, and some outdoor energy storage enclosures. In energy storage systems, batteries continuously generate heat during charging and discharging, and temperature is the most sensitive factor affecting battery safety and lifespan. Therefore, establishing a stable and reliable heat dissipation method is crucial. The air-cooled energy storage pack is a practical technical solution developed to meet this need.

The core principle of an air-cooled battery energy storage pack is to use a fan to force airflow through a set airflow path, allowing relatively cool outside air to pass through the battery module, continuously exchanging internal heat to remove excess heat. Its heat dissipation efficiency depends on factors such as fan power, airflow path design, battery layout, and environmental conditions. In terms of structural design, air-cooled energy storage packs typically have pre-installed air inlets and outlets, and use components such as ventilation screens and filter cotton to block dust. Internally, gaps between battery cells ensure airflow. To stabilize cooling, the system is also equipped with temperature sensors and a BMS (Battery Management System) to monitor battery temperature in real time and automatically adjust fan speed or activate cooling programs based on temperature changes.

Due to air cooling, air-cooled energy storage packs have significant advantages in cost and structure. Air, as a natural heat dissipation medium, requires no additional materials, resulting in a simpler system structure. The absence of complex components such as coolant piping, cold plates, and water pumps makes the overall cost lower than liquid-cooled solutions. Furthermore, it has fewer potential points of failure, is easier to maintain, and eliminates concerns about leaks, corrosion, or water pump lifespan. In small to medium-sized energy storage applications, this simple and cost-effective structure makes air cooling a mainstream choice.

However, the heat dissipation capacity of air-cooled energy storage packs is limited by ambient temperature and airflow. When the system is installed in high-temperature areas or enclosed spaces, the high temperature of the air itself leads to a significant decrease in heat dissipation efficiency. As the power density of energy storage systems continues to increase, the internal heat generation of batteries also increases. Air cooling may struggle to maintain ideal temperature control under high load and high temperature conditions, leading to larger temperature fluctuations and making temperature differences more difficult to control. This directly impacts battery life, causing cells within the same system to operate at different temperatures, resulting in inconsistent degradation rates. Furthermore, air cooling in high-temperature environments places higher demands on safety management, potentially requiring increased fan counts or enhanced air circulation to improve heat dissipation.

Despite this, air-cooled battery energy storage packs still hold a significant position in the market. For applications with lower power density requirements, milder temperature environments, and budget-sensitive needs, it is a mature and reliable choice. In commercial and industrial energy storage, air cooling is suitable for relatively low-intensity applications such as peak shaving and load smoothing. In residential energy storage, due to lower heat generation and limited size, air cooling easily meets heat dissipation requirements. Additionally, some energy storage systems emphasizing rapid deployment, such as outdoor integrated cabinets or leased energy storage devices, also tend to adopt air-cooled solutions due to their simple structure, ease of maintenance, and lower deployment costs.

With the development of energy storage technology, air-cooled battery energy storage packs are constantly being optimized. Manufacturers are improving their overall performance through more efficient airflow designs, more energy-efficient fans, and more intelligent temperature control algorithms, attempting to further improve heat dissipation efficiency without significantly increasing costs. Under reasonable environmental conditions and application scenarios, air cooling remains an economical and stable energy storage cooling method.

Overall, air-cooled battery energy storage packs are energy storage systems that use air as the primary heat dissipation medium. They regulate battery temperature by using fans to drive airflow, offering advantages such as simple structure, low cost, and easy maintenance, making them particularly suitable for small-scale and medium-power energy storage applications. As the energy storage industry continues to pursue economic efficiency and reliability, air cooling will remain an important component of energy storage cooling technology for a considerable period.

2. What is a Liquid-Cooled Battery Energy Storage Pack?

A liquid-cooled battery energy storage pack is an energy storage technology that uses a liquid circulation system for battery temperature control. Compared to traditional air cooling, it offers higher heat dissipation efficiency, more precise temperature control, and greater adaptability. As the power density of energy storage systems continues to increase, operating environments become more complex, and battery safety requirements continue to rise, liquid-cooled energy storage solutions are gradually becoming the industry mainstream, especially suitable for large-scale energy storage power stations, high-power industrial and commercial energy storage, and scenarios with stringent temperature control requirements.

The core principle of a liquid-cooled energy storage pack is to rapidly remove the heat generated by the battery during charging and discharging by circulating coolant between battery modules, inside cold plates, or in liquid-cooled pipelines. Compared to air, liquids have a higher specific heat capacity and higher thermal conductivity, thus absorbing a large amount of heat in a shorter time and releasing it stably through the heat sink. The entire system typically consists of coolant, liquid cooling plates, a circulating pump, a heat exchanger, temperature sensors, and a controller. During operation, the control system adjusts the flow rate or activates a cooling program in real time based on the battery temperature, ensuring the energy storage pack remains within the ideal temperature range.

The greatest advantage of liquid cooling technology is its excellent temperature consistency and precision control. Batteries exhibit significant temperature sensitivity during operation; excessively high temperatures accelerate aging, and uneven temperatures lead to inconsistent aging rates among individual cells, affecting the overall lifespan and safety of the entire pack. Liquid cooling systems can control battery temperature differences within a very small range, maintaining a highly consistent operating state across the entire battery cluster. This stability not only extends battery life but also improves the overall efficiency of the energy storage system, ensuring reliability even under high-rate charging/discharging or continuous long-term operation.

With the continuous expansion of energy storage scale, the advantages of liquid-cooled energy storage packs are becoming increasingly apparent. Large-scale energy storage power stations typically consist of hundreds or even thousands of energy storage units, with high power density and high operating intensity. If relying on air cooling, temperature accumulation is highly likely during high-temperature seasons or under high-load conditions, thus affecting system stability. Liquid cooling can maintain stable operation in harsh environments such as high outdoor temperatures, desert climates, and high humidity areas, ensuring the energy storage system remains safe and efficient year-round. Therefore, liquid cooling solutions are rapidly gaining popularity in new energy storage power plants, energy storage systems配套 with wind and solar power generation, and large-scale industrial and commercial energy storage projects.

Furthermore, as the energy storage industry pursues enhanced safety, liquid cooling systems are being given even greater value. Lithium batteries can experience thermal runaway under abnormal conditions, and liquid cooling systems can effectively suppress the rate of temperature rise, buying time for early warning and system protection. Some advanced liquid-cooled energy storage packs also integrate the liquid cooling system with the BMS (Battery Management System), using precise temperature measurement and dynamic control to rapidly cool the system in emergency situations, preventing further risk escalation. This capability is difficult to achieve with air cooling and is one of the key reasons why liquid-cooled energy storage packs are considered safer.

While liquid cooling technology exhibits significant performance advantages, its structure is more complex and its cost is higher than that of air-cooled solutions. Liquid cooling systems require more precise design, including pipe sealing, pump reliability, liquid longevity, and corrosion and leak prevention measures. Meanwhile, it requires professional personnel for installation and maintenance, has numerous potential points of failure, and demands higher standards for long-term operational monitoring and maintenance. However, in large-scale energy storage projects, these costs are usually offset by factors such as extended system lifespan, improved operating efficiency, and reduced safety risks.

In recent years, liquid-cooled energy storage packs have also been continuously iterating and upgrading. The next generation of liquid cooling technology is developing towards high-efficiency integration, including lighter module designs, more energy-efficient pumps, more intelligent temperature control algorithms, and module-level monitoring technology. Some advanced energy storage products even integrate the liquid cooling system with the battery enclosure, BMS, and fire suppression system, making the energy storage system both compact and highly safe and maintainable. With the maturity of liquid cooling technology and further cost reductions, it is gradually becoming an industry standard.

A liquid-cooled battery energy storage pack is an energy storage system that uses liquid as a heat dissipation medium and achieves efficient temperature control through circulating cooling technology. With its excellent heat dissipation efficiency, precise temperature control capabilities, high safety, and adaptability to complex environments, it is becoming the preferred solution in the medium to large-scale energy storage field. As the energy storage industry develops towards higher density and higher security, the value of liquid cooling technology will become increasingly prominent, and will continue to drive energy storage equipment towards greater reliability, efficiency, and intelligence.

3. In high-temperature environments, which is more reliable: air-cooled or liquid-cooled energy storage packs?

With the intensification of global climate change and the increasing frequency of high-temperature weather, the stability of energy storage systems in hot environments has become a focus of industry attention. Temperature not only affects battery life but also directly relates to safety. In high-temperature environments, the performance differences between traditional air-cooled energy storage packs and emerging liquid-cooled energy storage packs are becoming increasingly apparent. Therefore, many projects ask during the selection process: in high-temperature environments of 35℃, 40℃, or even 50℃, which cooling method is more reliable?

To answer this question, a comparison needs to be made from multiple dimensions, including heat dissipation capacity, temperature control accuracy, operational stability, and long-term safety.

First, heat dissipation efficiency at high temperatures is one of the key considerations. Air-cooled energy storage packs rely on air as a heat dissipation medium. High-temperature environments mean that the air temperature itself is high. When the ambient temperature is close to or higher than the optimal operating temperature range of the battery (generally 15℃～35℃), the heat that the air-cooling system can remove will be significantly reduced. Higher fan speeds result in greater noise and higher energy consumption, but heat dissipation efficiency is still limited by air temperature. Therefore, in environments above 40℃, air cooling often struggles to maintain a stable battery temperature control range, especially under high-rate or continuous charge-discharge conditions, easily leading to temperature accumulation and affecting system operation.

In contrast, liquid-cooled energy storage packs use coolant as the medium. The specific heat capacity of liquid is far higher than that of air, allowing for more rapid and effective heat dissipation from the battery. Even in high-temperature environments, liquid cooling systems can maintain strong heat dissipation capabilities through circulating pumps, heat exchangers, or refrigeration units. When the ambient temperature reaches 40℃ or even higher, liquid cooling can still control the battery temperature within a relatively narrow range, maintaining its ideal operating condition. Therefore, in hot regions such as the Middle East, Southeast Asia, large industrial parks, or outdoor energy storage stations, liquid cooling's heat dissipation efficiency is significantly superior to air cooling.

Secondly, there is the issue of temperature uniformity. The greater the temperature difference between batteries, the more inconsistent the rate of degradation, the worse the capacity consistency, and the more difficult it is to guarantee long-term performance and safety. Air cooling, due to unstable airflow paths, coupled with issues such as wind speed reduction, module obstruction, and air short circuits, is prone to generating large temperature differences. Some air-cooled energy storage packs experience internal temperature differences exceeding 10°C, which further amplifies aging variations between cells under high-temperature conditions.

Liquid cooling systems, on the other hand, can evenly cover the battery modules using cold plates or liquid cooling pipes, allowing the coolant to flow in a controlled direction and at a stable rate, thus maintaining a similar temperature across all cells. Most liquid-cooled energy storage packs can control temperature differences within 3°C, with advanced solutions achieving below 2°C. In long-term operation, this temperature uniformity not only improves cycle life but also significantly reduces the risk of thermal runaway.

Furthermore, there's the issue of system stability and safety. In high-temperature environments, air-cooled systems often need to operate at full speed for extended periods, increasing noise and energy consumption, and implying accelerated wear on mechanical components and a higher probability of failure. More importantly, if the system is under continuous full load, a decline in fan performance or blockage of air ducts by dust can lead to rapid temperature runaway, posing a greater safety hazard.

Liquid cooling systems, however, possess stronger resistance to external temperature disturbances. As long as the cooling circuit remains operational, liquid cooling systems can operate within a relatively independent temperature control path, reducing the direct impact of ambient temperature on the battery. Many liquid-cooled energy storage packs can even actively cool under extreme climates by linking the coolant with the refrigeration unit. High temperatures not only prevent the liquid cooling system from operating at full load but can also be smoothly managed by a rationally adjusted temperature control algorithm, thus ensuring long-term stable operation.

However, reliability depends not only on performance but also on system complexity and maintenance requirements. Air-cooled systems have a simpler structure, fewer points of failure, are easier to maintain, and are less expensive. However, in high-temperature regions, to compensate for heat dissipation capacity, it is often necessary to increase airflow, the number of fans, or upgrade the enclosure's heat dissipation structure, which actually increases maintenance workload and operating costs.

While liquid cooling systems are structurally more complex, modern liquid cooling solutions have significantly reduced failure rates. Longer pump lifespan, improved coolant stability, and mature sealing technology enable liquid cooling systems to operate continuously for many years. In high-temperature regions, liquid cooling systems are not only more stable but also offer greater safety redundancy.

In summary, in environments with consistently low temperatures, air-cooled energy storage packs still offer advantages such as low cost and ease of maintenance, making them suitable for small to medium-sized energy storage applications. However, in areas with extreme summer temperatures, continuous high-load conditions, large-scale energy storage power stations, and applications with extremely high safety requirements, liquid-cooled energy storage packs are undoubtedly more reliable. They not only meet the challenges of high-temperature environments but also improve battery life, consistency, and overall safety.

Therefore, if the project is located in a high-temperature region or the energy storage system requires long-term high-power operation, then a liquid-cooled solution is almost certainly the more reasonable choice. In scenarios with milder temperatures and lower power requirements, air cooling remains a cost-effective solution. The final selection should be based on a comprehensive assessment of the application scenario, budget, safety requirements, and long-term operation and maintenance costs.

4. What are the advantages and characteristics of air-cooled and liquid-cooled energy storage packs?

With the large-scale application of energy storage systems, battery temperature control has become a crucial factor affecting the stability, safety, and lifespan of energy storage. Currently, the industry mainly uses air-cooling and liquid-cooling methods, each with its own distinct technical characteristics and application advantages. To facilitate selection and understanding, the advantages and characteristics of air-cooled and liquid-cooled energy storage packs will be introduced below in terms of performance, structure, safety, and application adaptability.

(1) Advantages and characteristics of air-cooled energy storage packs:
Simple structure and lower system cost:
Air-cooled systems mainly rely on fans, air ducts, and external air for heat dissipation. Due to the absence of complex components such as liquid channels, cold plates, and pumps, manufacturing costs are low, and the assembly process is simple, making the overall system lighter. For projects with limited budgets or low heat dissipation requirements, air cooling can significantly reduce procurement costs while ensuring basic temperature control.

Easy maintenance and high reliability:
One advantage of air-cooled energy storage packs is their ease of maintenance. The fan is the main maintainable component; routine checks typically only require cleaning the filter and confirming the fan's operating status. Due to its simple structure and fewer potential points of failure, air-cooled energy storage packs eliminate risks such as liquid leaks and electric pump malfunctions, making them more reliable in environments lacking specialized maintenance personnel.

Easy Installation and Deployment, Suitable for Lightweight Scenarios: Air-cooled energy storage packs are lightweight and flexible in size, requiring no additional liquid cooling equipment or piping. Therefore, they are commonly used in residential, mobile, and small-scale commercial energy storage applications. Whether wall-mounted, rack-mounted, or simply deployed outdoors, air-cooled solutions offer faster installation efficiency.

High Cost-Effectiveness, Suitable for Low-to-Medium Power Density Systems: For applications with low heat generation and low operating intensity, such as home photovoltaic energy storage systems, small UPS systems, and distributed photovoltaic energy storage, air cooling provides sufficient heat dissipation to meet operational needs and achieve stable operation at a lower cost. This gives them long-term competitiveness in certain cost-sensitive markets.

Fast System Response and Controllable Noise: Air-cooled systems can quickly respond to temperature changes by adjusting fan speed, offering flexible adjustments and efficiently meeting the dynamic temperature control requirements of the system. Modern air-cooled systems also employ low-noise fans and optimized airflow designs, balancing heat dissipation efficiency and operational comfort.

(2) Advantages of Liquid-Cooled Energy Storage Packs
Strong Heat Dissipation Capacity, Suitable for High Heat Load Conditions:Liquid cooling systems rely on coolant circulating in liquid cooling plates or channels to achieve efficient heat exchange. Liquids have a much higher specific heat capacity than air, thus quickly removing a large amount of heat. Whether for high-rate charging and discharging, continuous full-power operation, or outdoor applications in high-temperature seasons, liquid cooling is significantly superior to air cooling in terms of heat dissipation efficiency.

High Temperature Control Accuracy, Small Battery Temperature Difference:Battery consistency determines the lifespan of the energy storage system, and temperature difference is a key factor affecting consistency. Liquid cooling systems can control the battery temperature difference within 2–3℃, far less than the common 6–10℃ temperature difference range of air-cooled energy storage packs. This temperature consistency not only slows down degradation but also significantly improves the overall lifespan and stability of the energy storage pack. High-Temperature Adaptability and Enhanced Reliability for Continuous Operation

In environments where ambient temperatures exceed 35°C or even 40°C, air cooling efficiency significantly decreases. Liquid cooling systems, however, are independent of ambient air temperature, maintaining stable temperature control through liquid circulation and heat exchange devices. Therefore, in extreme environments such as the Middle East, high-altitude regions, and high-temperature factories, liquid-cooled energy storage packs are almost the only solution for long-term reliable operation.

Higher Safety and Effective Reduction of Thermal Runaway Risk
Batteries are more prone to thermal runaway under high temperatures or prolonged loads. Liquid cooling, with its excellent heat absorption capacity, can quickly remove heat generated by the battery cells, preventing localized overheating of the system. Simultaneously, the linkage between liquid cooling and the BMS enables more precise temperature monitoring, allowing for early detection and response to abnormal temperatures, thus improving overall safety.

Suitable for Large-Scale Power Plants, High-Density Energy Storage, and Advanced Applications
As energy storage develops towards "large capacity, high density, and high power," liquid cooling has become the mainstream solution for newly built large-scale energy storage power plants. Whether it's an outdoor integrated cabinet, a containerized energy storage station, or an integrated power station combining generation, grid, load, and storage, liquid cooling maintains high stability over long-term operation, with an overall system lifespan superior to air-cooled solutions.

Superior Lifecycle Economics
Although liquid cooling has a higher initial cost, its advantages, such as reduced degradation, less maintenance, and more stable long-term operation, make it more economically valuable in the long run. For scenarios with frequent charging and discharging or high performance requirements, the overall benefits of liquid cooling solutions far outweigh those of air-cooled systems.

Air-cooled energy storage packs, with their core advantages of "simplicity, economy, and convenience," are suitable for small to medium-sized energy storage scenarios with light loads, mild environments, and budget constraints.

Liquid-cooled energy storage packs, with their main advantages of "strong heat dissipation, high stability, and high safety," are more suitable for specialized applications such as high-temperature, high-power-density, and large-scale energy storage power stations.

Comparison of advantages and features between air-cooled and liquid-cooled energy storage packs：

5. Frequently Asked Questions about Air-Cooled and Liquid-Cooled Energy Storage Packs

With the development of the energy storage industry, air cooling and liquid cooling have become the two most mainstream battery temperature control methods. However, many users still have questions about how to choose between them, the differences in application scenarios, and safety differences.

Q1. What are the main differences between air-cooled and liquid-cooled energy storage packs?
Air cooling primarily uses a fan to drive airflow to remove heat; liquid cooling uses coolant flowing through cold plates or liquid cooling pipes to dissipate heat. The former has a simpler structure and lower cost, while the latter has stronger heat dissipation capabilities and higher temperature control accuracy. Simply put, air cooling is more suitable for lightweight, low-heat-dissipation scenarios; liquid cooling is more suitable for high-power, high-temperature, and high-safety scenarios.

Q2. Which heat dissipation method is more suitable for high-temperature environments?
Liquid-cooled energy storage packs have a greater advantage in high-temperature environments.
When the ambient temperature exceeds 35℃, the air's heat dissipation capacity decreases, limiting the efficiency of air-cooled systems. Liquid-cooled systems, however, do not rely on air temperature; they exchange heat through circulating coolant, enabling stable control of battery temperature. Therefore, in conditions such as deserts, high-temperature factories, and exposed environments at the seaside, liquid cooling is significantly more reliable than air cooling.

Q3. Will insufficient heat dissipation cause safety issues with air-cooled energy storage packs?
Under normal operating conditions and with proper design, air-cooled energy storage packs are safe. However, the risk increases in the following situations:
High ambient temperature (> 40℃)
Continuous high-rate charging and discharging of the battery
Blocked air ducts, aging or damaged fans
Insufficient heat dissipation space
Therefore, air-cooled systems are more suitable for light-load, low-to-medium power density scenarios. For more demanding environments, liquid-cooled systems offer more reliable safety.

Q4. Is there a risk of leakage with liquid-cooled systems? Does it affect safety?
Liquid-cooled systems do have a risk of liquid leakage, but standard designs use insulating coolants and are equipped with leak detection and pressure monitoring devices. As long as proper installation, regular maintenance, and compliant design are implemented, liquid-cooled systems are very safe. In actual projects, the high temperature control accuracy of liquid-cooled systems reduces the risk of thermal runaway, making their overall safety superior to air-cooled systems.

Q5. What scenarios are air-cooled energy storage packs suitable for?
Air-cooled solutions are generally used in scenarios with lower heat dissipation requirements, discontinuous loads, and cost sensitivity, such as: Residential photovoltaic-storage systems; Small commercial energy storage; Mobile energy storage vehicles; Small energy storage stations in cooler regions; UPS or backup power supply scenarios. In these scenarios, heat generation is limited, and air cooling can adequately meet operational needs.

Q6. What are the typical applications of liquid-cooled energy storage packages?
Liquid cooling is more suitable for high-intensity, large-scale applications, such as: Containerized large-scale energy storage power stations; High-load energy storage systems in industrial parks; Grid-friendly frequency regulation/peak shaving energy storage; Projects requiring long-term full-power operation; Harsh environments such as high temperatures, coastal areas, and deserts. These environments have high requirements for heat dissipation capacity, reliability, and temperature control accuracy, making liquid cooling the mainstream choice.

Q7. Is a liquid cooling system more energy-efficient than air cooling?
In low-load scenarios, air cooling is more energy-efficient because the fan consumes less power. However, in high-load or high-temperature environments, liquid cooling has higher heat dissipation efficiency, achieving effective cooling with lower energy consumption, thus being more energy-efficient. Therefore, power consumption cannot be simply compared; a comprehensive judgment should be made based on the specific application scenario.

Q8. Why are liquid-cooled energy storage packs becoming increasingly popular?
The industry is moving towards "high capacity, high power, and high energy density," leading to more stringent requirements for battery thermal management. Liquid cooling offers advantages including: precise temperature control, small temperature difference, strong heat dissipation, longer battery life, better system stability, and support for higher energy density designs. These factors make it the mainstream configuration for large-scale energy storage power stations.

Q9. Will air-cooled energy storage packs be completely replaced by liquid cooling?
No.
Air cooling still has irreplaceable advantages in many scenarios, such as: cost-sensitive markets, scenarios with limited installation locations, mobile energy storage, residential energy storage, and temperate climates. While liquid cooling offers superior performance, its higher cost and more complex structure prevent it from fully covering the lightweight market segment where air cooling is prevalent.

Q10. How to determine whether to choose air cooling or liquid cooling?
You can judge based on the following three core indicators:
Is the power density high? If so, prioritize liquid cooling.
Is the ambient temperature extreme? Choose liquid cooling for high-temperature scenarios.
Is your budget limited? For cost-sensitive scenarios, air cooling is preferable.
Ultimately, a comprehensive evaluation should be conducted considering factors such as project scale, application load, ambient temperature, and operational capabilities.

Air-cooled and liquid-cooled energy storage packages each have their advantages; there is no absolute superiority or inferiority. The correct choice should be based on the application scenario, heat load, ambient temperature, and budget requirements. By fully understanding the characteristics and differences between the two, energy storage systems can achieve higher efficiency, longer lifespan, and enhanced security.