Thermal Management Industry Embraces Broad Prospects with Ample Opportunities in Niche Segments
The market size may grow steadily, and the penetration rate of liquid cooling is expected to continue to increase: my country’s dual-carbon policy is currently being accelerated, and the new energy track has broad space. Benefiting from the vigorous promotion of the dual-carbon policy, China’s domestic energy storage temperature control, new energy vehicle thermal management and other temperature control equipment application scenarios have maintained rapid growth. In addition, with the development of the Internet, big data, cloud computing, and informatization, the demand for temperature control equipment in data centers and 5G base station application scenarios is also relatively strong. Guanyan Tianxia said that it can be foreseen that the market size of my country’s temperature control equipment may grow steadily in the future.
In terms of technical path, China’s temperature control equipment inventory will continue to be dominated by air cooling in the future, but the penetration rate of liquid cooling is expected to continue to increase: the liquid cooling system mainly includes water cooling plates, water cooling pipes, water cooling systems, heat exchange fans, etc.; and the air cooling system structure is relatively simple. Compared with the two, the design difficulty of the liquid cooling system is complex and the cost is higher, but its heat dissipation efficiency and speed are high, and it has a wide range of applications and occupies less space.
Currently, SmartPropel Energy is promoting outdoor liquid-cooled 200KW/372KWh industrial and commercial solar energy battery storage cabinet, whose advantages are mainly proximity to heat sources, uniform temperature, and low energy consumption. They are also more suitable for outdoor environments than air cooling. At the same time, manufacturers such as Sungrow Power and BYD are also actively launching liquid cooled high voltage lithium iron phosphate battery cabinet system products for outdoor energy storage systems. Outdoor liquid-cooled electric cabinets can be widely used in photovoltaic energy storage, wind power energy storage, grid energy storage, commercial energy storage and other energy storage scenarios. In the future, the penetration rate of liquid cooling technology products for temperature control equipment in China is expected to continue to increase.
Air and Liquid Cooling in Scaled Application; Emerging Technologies Include Heat Pipe and Phase Change Cooling
Three Temperature Ranges of Lithium-Ion Batteries
At present, there are four main temperature control technologies that can be used in large-capacity lithium-ion battery energy storage systems, which are suitable for application scenarios with different heat generation rates and ambient temperatures:
Air cooling: using air as the medium for heat exchange, it has the advantages of simple structure, light weight, high reliability, long life and low cost. However, due to the low specific heat capacity and thermal conductivity of air, the heat dissipation speed and efficiency of the air cooling system are not high, so air cooling is more suitable for occasions with low heat generation rate of the battery;
Liquid cooling: using liquid as the medium for heat exchange, the liquid cooling medium has a high heat transfer coefficient, large specific heat capacity, and fast cooling speed, which can effectively reduce the maximum temperature of the battery and improve the uniformity of temperature distribution; the liquid cooling system has a complex structure and high cost, but has a high heat dissipation speed and efficiency. At present, most electric vehicles use Liquid cooling system;
Heat pipe cooling: Relying on the phase change of the cooling medium in the pipe to achieve heat exchange, it has higher heat dissipation speed and efficiency than the liquid cooling system, and has a lower risk of cooling medium leakage, but the cost is higher; it is suitable for lithium battery systems that often work at high rate conditions;
Phase change cooling: Absorbing heat through phase change materials, and combining air cooling, liquid cooling, air conditioning systems to export heat, it has the advantages of compact structure, low contact thermal resistance, and good cooling effect, but phase change materials take up space and are expensive; it is often used in combination with other thermal management technologies to achieve uniform battery temperature distribution, reduce contact thermal resistance, and increase heat dissipation speed.
Advantages of Liquid Cooling: Direct and Indirect Contact Methods
Main Components of a Liquid Cooling System
Liquid Cooling Pipeline Layout
Liquid cooling: Liquid is used as the cooling medium to remove the heat generated by the battery through convection heat transfer.
Main components: liquid cooling plate, liquid cooling unit (heater optional), liquid cooling pipeline (including temperature sensor, valve), high and low pressure wiring harness; coolant (ethylene glycol aqueous solution), etc.
There are two contact modes between liquid and battery: one is direct contact, the battery cell or module is immersed in liquid (such as electrically insulating silicone oil), allowing the liquid to directly cool the battery; the other is to set a cooling channel or cold plate between the batteries, allowing the liquid to indirectly cool the battery.
There are certain technical barriers to liquid cooling solutions. The application of direct contact liquid cooling is still immature. The indirect contact type needs to be customized according to the actual application, such as the number of flow channels, flow rate, flow rate, etc. For different projects of different energy storage integrators, the thermal management solutions vary greatly. For liquid cooling host suppliers, their core competitive factors lie in customization capabilities and long-term know-how accumulation of heat dissipation solutions.
The liquid cooling plate is a key component for thermal management of the liquid cooling system. Before manufacturing, it is often necessary to jointly develop and design with customers, confirm the selection and match it with the battery. At present, the battery liquid cooling plate is still in an oligopolistic competition pattern. The liquid cooling plate often needs to be integrated with the battery system. The production line is non-standard and the product is highly customized. It is not easy to switch between different processes. Downstream customers will give priority to manufacturers with liquid cooling plate design capabilities.
Technology Trends: Air Cooling Dominates Currently, with Liquid Cooling Share Expected to Rise in the Mid-Term
Comparison of Capital Investment Between Air Cooling and Liquid Cooling Systems
Comparison of Operating Energy Consumption Between Air Cooling and Liquid Cooling
Energy storage temperature control is mainly based on air cooling and liquid cooling. We mainly compare the two from four aspects: battery pack temperature, operating energy consumption, battery thermal runaway risk, and fixed asset investment:
Battery pack temperature: Under the same inlet temperature and extreme wind speed and flow rate, the temperature of the liquid-cooled battery pack is 30-40 degrees Celsius, while the temperature of the air-cooled battery pack is 37-45 degrees Celsius; liquid cooling has better temperature uniformity.
Operation energy consumption: According to experimental research, in order to achieve the same average battery temperature, air cooling requires 2-3 times more energy consumption than liquid cooling; the maximum temperature of the battery pack under the same power consumption, air cooling is 3-5 degrees Celsius higher than liquid cooling; liquid cooling has lower power consumption.
Battery thermal runaway risk: Due to factors such as air specific heat capacity and small convection heat transfer coefficient, the heat transfer efficiency of battery air cooling technology is low, the battery heat generation increases, which will cause the battery temperature to be too high and there is a risk of thermal runaway; the liquid cooling system can greatly reduce the risk of thermal runaway of the battery.
Fixed asset investment: According to NREL data, the current battery investment cost for a 4-hour battery energy storage system is 1,900 RMB (300 USD) per kilowatt-hour. The thermal management system is estimated to account for 2-4% of the battery cost. The liquid cooling system can more easily ensure that the battery operates at a comfortable temperature. Compared with the air cooling system, it can extend the battery life by more than 20%. In terms of the overall life cycle, liquid cooling investment is less.
At present, energy storage temperature control is mainly air cooling, mainly due to the following reasons:
1) The current energy storage projects have relatively low requirements for cooling efficiency: the projects with relatively small power density and power density such as communication base stations and small ground power stations account for a relatively high proportion of installed capacity in the industry, and the cooling efficiency of the air cooling solution can meet the safety standards of the project;
2) The cost of air cooling equipment is lower than that of liquid cooling, and the current energy storage projects are more sensitive to costs: the value of air cooling and liquid cooling per GWh is about RMB 30 million and RMB 90 million, of which the liquid cooling host is about RMB 50 million. Since the current energy storage projects are not economical in some application scenarios, coupled with the current rising battery costs, downstream demand is highly sensitive to installation costs, so they tend to choose lower-cost air cooling solutions.
We expect that the proportion of liquid cooling will continue to rise in the medium term, mainly because the heat generation of energy storage projects will continue to increase, and the cooling efficiency of air cooling may not be able to meet the heat dissipation needs of some projects: In the medium term, the installed capacity of energy storage projects with larger battery capacity and higher system power density, such as new energy power stations and off-grid energy storage, will increase, and the requirements for peak and frequency regulation performance of power storage will increase, which will drive the average heat generation of energy storage projects to increase. At that time, the demand for liquid cooling with higher cooling efficiency will be expected to increase.
In addition, the choice of technical direction is related to the environment and heat generation of the project. For example, air cooling in extremely high temperature areas will affect the cooling effect, and liquid cooling in extremely low temperature areas will have the risk of icing; air cooling is sufficient to meet the needs of projects with lower heat generation, while liquid cooling is required for projects with higher heat generation; Therefore, in the medium term, although the proportion of liquid cooling will increase, the two technologies will still have their application scenarios. Newly installed energy storage projects are likely to choose air cooling solutions:
1) Located in extremely low temperature and water-scarce areas;
2) Small ground power stations, household, and communication base station projects with low heat generation; liquid cooling solutions are likely to be chosen: Located in extremely high temperature areas.
Rapid Growth in Energy Storage Demand and Liquid Cooling Adoption Expands the Thermal Management Market
Energy storage application scenarios involve a variety of power scenarios such as the power supply side, the grid side, the user side, and distributed microgrids. The diversity of application scenarios determines the diversification of energy storage technology. Among them, electrochemical energy storage technologies represented by lithium-ion batteries, sodium-ion batteries, and flow batteries have achieved rapid development both at home and abroad in recent years, and the scale of application has moved from megawatt-level demonstration applications to gigawatt-level large-scale applications. The global installed capacity of electrochemical energy storage is expected to be about 65GWh, and it can reach 1160GWh by 2030, of which 70% comes from the power generation side, which is the main source of power to support electrochemical energy storage installations.
The energy storage temperature control market is expected to reach 16.5 billion RMB in 2025: According to data disclosed in 2020, the value of energy storage temperature control accounts for about 3%-5% of the value of the entire energy storage system. According to national policies on reducing the cost of energy storage systems, diversified energy storage systems will be strongly promoted, and the value of energy storage temperature control is expected to continue to increase. According to GGII statistics, the shipment volume of power energy storage systems in 2021 was 29GWh, a year-on-year increase of 341%. The high growth of electrochemical energy storage systems is driving the rapid development of energy storage temperature control. According to GGII estimates, the scale of China’s energy storage temperature control market will increase from 4.66 billion yuan to 16.46 billion yuan from 2022 to 2025, with a CAGR of 52.3%. Liquid cooling, as a medium- and long-term technical solution, may gradually increase its market penetration. GGII predicts that the market share of liquid cooling will reach about 45% in 2025.
