Introduction of temperature controller in energy storage

Driven by factors such as the popularization of renewable energy power generation, battery cost reduction, and low-carbon emission reduction, the installed capacity of energy storage is expected to continue to increase in the future, and the proportion of new energy storage (electrochemical energy storage, etc.) will also gradually increase.

Why do energy storage systems need temperature controller

This is due to the explosive growth of the energy storage market. The temperature controller is a key measure to prevent the capacity decay, life shortening, and thermal runaway of the energy storage system.

The basic requirements of temperature controller: temperature controller control the surface temperature and humidity of the single battery + avoid local hot spots in the battery system.

Temperature has a great impact on the performance of lithium batteries in electrochemical storage systems, such as capacity, power, and safety. Therefore, in practical applications, effective thermal management system of batteries is required.

Compared with the power battery system, the storage system gathers more batteries, and the battery capacity and power are also larger: A large number of batteries are closely arranged in a space, and the operating conditions are complex and changeable, sometimes high rate, sometimes low rate, which is easy to cause problems such as uneven heat production, uneven temperature distribution, and large temperature difference between batteries.

These problems may lead to a decline in the charge-discharge performance, capacity, and lifespan of some batteries, thereby affecting the performance of the entire system. In severe cases, thermal runaway may occur, resulting in safety accidents. The effects of temperature on the performance of lithium batteries systems include:

Capacity fade:
The loss of active lithium-ion batteries at high temperatures leads to the capacity decay of lithium iron phosphate batteries, which makes the actual operating capacity of the battery storage system rapidly decay.

Thermal runaway:
During the charging and discharging process of the battery, part of the chemical energy (discharging) or electrical energy (charging) will be converted into heat energy, if the heat energy cannot be dissipated in time and accumulate inside the battery to form a high temperature, it may cause a short circuit of the positive and negative electrodes, causing safety problems such as combustion and explosion, in the storage system, a thermal runaway of a battery may cause a chain effect and cause a major accident.

Low temperature characteristics:
The transport properties of the electrolyte, the diffusion rate of lithium, and the charge transfer rate at the interface between the electrode and the electrolyte all decrease significantly at low temperatures, and thus the capacity of the lithium battery decreases.

Therefore, cycling of lithium batteries at low temperatures may lead to the precipitation and accumulation of lithium in the negative electrode, and the formation of lithium dendrites, which may cause irreversible capacity loss, reduce the capacity and thermal safety of the battery, or puncture the diaphragm and cause a short circuit.

This is due to the explosive growth of the energy storage market. In addition to stipulating that ternary lithium battery shall not be used in large energy storage systems, temperature controller is a key measure to prevent the capacity decay, life shortening, and thermal runaway of the storage system.

The storage system has a large number of batteries, large battery capacity and power, and requires effective battery thermal management.

Otherwise, it may lead to a decline in battery charge and discharge performance, capacity, and life, or even lead to thermal runaway, resulting in safety accidents.

In addition, under the general trend of large-capacity energy storage systems on the power generation side and high battery rates of storage systems for peak regulation and frequency regulation, the importance of temperature controller will continue to increase.

Requirements for temperature controller in energy storage systems

Control the surface temperature and humidity of the single battery: maintain the best working temperature and humidity,
1) Temperature +15°C-+35°C;
2) The relative humidity is between 5%-95% and there is no condensation;

Avoid local hot spots in the battery system: The temperature difference between cells does not exceed 5°C to avoid local hot spots. With the trend of large-capacity storage systems and high battery rates, temperature controller is becoming more and more important.

Classified by function, electrochemical energy storage can be divided into two types: energy-based energy storage (high energy input/output) and power-based energy storage (instantaneous high-power input/output). From the general trend of large capacity and high battery rate, the importance of temperature controller will continue to rise in the future.

Energy storage:

It needs to meet the discharge demand for a long time, and is suitable for energy storage on the new energy generation side, peak-valley spread arbitrage on the user side, etc. The future trend is that the project capacity will continue to expand.

Looking forward to the future, under the general trend of high growth rate of installed capacity + expansion of allocation and storage ratio of new energy power generation projects such as wind and solar, energy storage projects on the power generation side are expected to accelerate the increase in volume, and the project capacity will also expand.

Therefore, for energy-based storage projects, the increase in the capacity of the battery system will increase the heat production of the project, and the demand and importance of temperature controller will increase accordingly.

Power storage:

It needs to meet high-power discharge requirements, and is suitable for grid-side peak regulation and frequency regulation scenarios. The future trend is to increase the rate of batteries.

Scenarios such as joint frequency regulation of thermal power units and auxiliary services of storage and frequency regulation on the grid side require batteries to achieve high-rate charge and discharge requirements, meet minute-, second-, and even millisecond-level power regulation capabilities, and respond quickly to load changes.

Looking forward to the future, the increase in the installed capacity of new energy power generation projects will increase the demand for peak regulation and frequency regulation on the grid side.

The high rate of the battery drives the power density of the energy storage system to continue to increase, so the heat generation will continue to increase, and the demand and importance of temperature controller will also increase.

Large-capacity lithium battery energy storage temperature controller technology

At present, the temperature controller technologies that can be used in large-capacity lithium-ion battery storage systems mainly include air cooling and liquid cooling.

Air cooling and liquid cooling temperature controller technologes have been applied on a large scale, and the technologies under development include heat pipe cooling and phase change cooling.

Air cooling temperature controller technology:

Heat exchange with air as medium. Air cooling has simple structure, low cost and easy maintenance. Compared with liquid cooling and phase change material cooling, air cooling has better stability.

However, the low thermal conductivity of air limits the cooling performance of the air cooling system, so the cooling speed of the air cooling system is slow and the heat dissipation effect is poor.

Although forced air cooling can enhance airflow movement and improve heat dissipation efficiency, the use of fans or air pumps to force convection will cause system energy loss.

Liquid cooling features temperature controller technology:

Heat exchange with liquid as medium. The coolant of liquid cooling is liquid. Compared with air, liquid has the advantages of larger specific heat capacity, fast temperature transfer, and large heat absorption.

The heat removed by the same volume of liquid is significantly greater than that of air cooling, and the efficiency of heat conduction is also significantly higher than that of air cooling, and the liquid cooling technology has obvious advantages.

For relevant industry information, please refer to energy storage liquid cooling companies.

Competitive analysis of energy storage temperature controller industry

Industry competition

With the advantages of technical homology and lower switching costs, temperature controller companies have successively deployed energy storage tracks.

Energy storage temperature controller and data centers, industrial refrigeration equipment have certain similarities in system design, heat dissipation methods, temperature controller requirements, etc.

The experience and technology of temperature controller technology subdivision track companies can be transplanted into energy storage scenarios and become important players.

Potential competition

For general civil air-conditioning companies, it is not easy to enter the temperature controller field across borders, and there are certain technical barriers in the industry.

The temperature controller requires higher temperature controller technology and operational reliability than the civil refrigeration field.

For ordinary civil air conditioners, the air conditioners used in the air cooling system need to be upgraded accordingly in terms of air circulation, heat dissipation efficiency, stability, service life, and reliability.

Downstream customers

Diversified scenarios to meet the customization needs of temperature controller products.

There are different application scenarios downstream of energy storage, and the requirements for temperature controller products are different, and there are strong differences in models and customer needs.

Due to the high degree of customization, sufficient project experience and customer accumulation are required to form an advantage.

Upstream suppliers

There are many kinds of raw materials, and there are many customized materials. The cost side of the temperature controller companies mainly includes the refrigeration equipment group, the electronic component group, the copper-aluminum cable and other basic material groups.

Due to different application scenarios and downstream customers, there are certain differences in the overall proportion. On average, standardized raw materials purchased account for about 60%, and customized materials account for 40%.

Alternatives

With better heat dissipation properties and temperature uniformity, energy storage products using liquid cooling technology will gradually replace air cooling.