Liquid cooling energy storage becomes mainstream
The energy storage industry is booming, and the cumulative installed capacity of new energy storage has reached 13.1GW. The new energy storage industry is full of vigor and vitality, hope and challenge coexist.
Energy storage should develop in the direction of large-scale, medium-to-long term, strong tolerance and high safety performance.
Liquid cooling has become a popular technical route on the thermal management track. Most of the new products of top 10 lithium ion battery manufacturers in China have added liquid cooling.
Thermal management of energy storage
Because of the thermal characteristics of batteries, thermal management has become a key link in the electrochemical energy storage industry chain.
From the perspective of the value and volume of the industrial chain, the cost of energy storage batteries in energy storage systems accounts for about 55%, PCS accounts for about 20%, BMS and EMS together account for about 11%, and thermal management accounts for about 2%-4%.
Thermal management accounts for a relatively small amount of value, but it plays a vital role. Thermal management is the key to ensuring the continuous and safe operation of energy storage systems.
The energy storage system generates a lot of heat and has limited space for heat dissipation. It is difficult to achieve temperature control under natural ventilation, and it is easy to damage the life and safety of the battery.
Compared with the power battery system, the batteries of the energy storage system have higher power, more quantity, and stronger heat generation, and the tight arrangement of the batteries leads to limited heat dissipation space, making it difficult to dissipate heat quickly and evenly, which may easily cause friction between the battery packs.
Heat accumulation and excessive operating temperature difference lead to frequent safety accidents of the energy storage system, which will eventually damage the life and safety of the battery.
Ideally, the thermal management design can control the temperature inside the energy storage system in the optimal temperature range for lithium battery operation (10-35°C) and ensure the temperature uniformity inside the battery pack, thus reducing the risk of battery life degradation and thermal runaway.
Energy storage thermal management technology route
At present, the mainstream technical routes of energy storage thermal management are air cooling and liquid cooling. Energy storage thermal management technology routes are mainly divided into air cooling, liquid cooling, heat pipe cooling, and phase change cooling, among which heat pipe and phase change cooling technologies are not yet mature.
The battery temperature is lowered by gas convection. It has the advantages of simple structure, easy maintenance, and low cost, but the heat dissipation efficiency, heat dissipation speed and temperature uniformity are poor. Suitable for occasions with low heat generation rate.
The battery temperature is reduced by liquid convection. The heat dissipation efficiency, heat dissipation speed and temperature uniformity are good, but the cost is high, and there is a risk of cooling liquid leakage.
It is suitable for occasions with high energy density of battery packs such as ternary lithium batteries, fast charging and discharging speeds, and large changes in ambient temperature.
Heat Pipe & Phase Change
The heat dissipation of the battery is achieved through the evaporation and heat absorption of the medium in the heat pipe and the phase change conversion of the material.
Among them, the liquid cooling technology directly dissipates heat through liquid convection, which can realize precise temperature control of the battery and ensure uniform cooling.
In contrast, the cost of air cooling technology is lower, but the heat dissipation efficiency is not high, and it is impossible to achieve precise temperature control of the battery.
Therefore, in low power scenarios, air cooling is still the mainstream, while in medium and high power scenarios, liquid cooling technology occupies a dominant position.
The liquid cooling system has the advantages of large specific heat capacity and rapid cooling, which can more effectively control the temperature of the battery, thereby ensuring the stable operation of the energy storage battery.
Liquid-cooled energy storage market
The energy storage market is thriving. Downstream energy storage integrators and lithium battery manufacturers have begun the process of deploying energy storage liquid cooling technology early, developing new products and updating product iterations with new technologies.
With the involvement of more and more practical application projects, liquid-cooled energy storage systems are rapidly becoming the mainstream technology route in the market.
At present, the proportion of liquid cooling technology in new large-scale storage projects on the power generation side/grid side is rapidly increasing, such as the 100MW/200MWh shared energy storage power station demonstration project of Ningxia Power Investment Ningdong Base, Gansu Linze 100MW/400MWh shared energy storage power station project etc.
And the application in actual projects is gradually increasing. For example, the Southern Power Grid Meizhou Baohu energy storage power station was officially put into operation in Wuhua County, Meizhou City, Guangdong Province recently. This is also the world’s first submerged liquid-cooled energy storage power station.
For the first time, China Southern Grid Energy Storage Company directly immersed the battery in the coolant in the cabin to achieve direct, rapid and sufficient cooling and cooling of the battery to ensure that the battery operates within the optimal temperature range.
Future potential of liquid cooling energy storage
The explosion of the energy storage market will continue. In order to effectively promote the consumption of new energy power, the release of large-scale and high-capacity energy storage power stations is accelerated.
As an important part of the energy storage system, the thermal management system will benefit from the increase in the installed capacity of energy storage. The scale of the energy storage temperature control market may continue to expand.
According to statistics, in 2022, China’s new energy storage projects will reach 7.3GW/15.9GWh, and the cumulative installed capacity will reach 13.1GW/27.1GWh.
Combined with the planning situation of various regions, it is estimated that by the end of 2025, the cumulative installed capacity of energy storage in China is expected to reach nearly 80GW.
According to analysis, the value of China’s energy storage temperature control shipments will reach 16.5 billion yuan in 2025. With the increase in energy storage capacity and charge-discharge rate, the proportion of medium and high-power energy storage products using liquid cooling will gradually increase, and liquid cooling is expected to become the future
The mainstream solution, in which the penetration rate of liquid cooling technology is expected to reach about 45% by 2025.
In the future, as renewable energy power stations and off-grid energy storage require larger battery capacity and higher system power density, the proportion of liquid-cooled energy storage will increase. Liquid-cooled energy storage will surely become the mainstream of the energy storage market by virtue of its comprehensive advantages.
It will stimulate energy storage system manufacturers’ enthusiasm for continuous deployment of new products and new technologies, promote the safety and economical improvement of energy storage systems, and provide more effective energy storage solutions.