In the face of surging market demand and complex application scenarios, global energy storage safety accidents occur frequently, including projects involving some well-known energy storage suppliers. For example, on July 30, 2021, the world's largest battery energy storage project using Tesla's Megapack, Australia's "Victoria Large Battery", caught fire, and the fire burned for 4 days before it went out.
In contrast, in China, three typical energy storage safety accidents have occurred one after another in the past year.
On April 16, 2021, the news of a fire and explosion during the commissioning of an energy storage power station in Fengtai, Beijing, was hotly searched. Firefighters fought for 12 hours to completely extinguish the fire. The accident not only caused direct property losses of 16.6081 million yuan, but also caused many casualties, including 2 firefighters. This first domestic energy storage explosion accident attracted the attention of many media reports, and for the first time, the safety topic was brought to the front of the fire department, making all industries face up to the hidden dangers of the energy storage industry.
On January 12, 2022, a truck full of energy storage systems on the Beijing-Hong Kong-Macao Expressway suddenly caught fire. Fortunately, the driver found it in time, parked the accident vehicle in the emergency lane and called the police. When the fire rescue personnel arrived at the scene, the inside of the truck was burning violently. , the flames sprayed outwards from time to time, and billowing smoke was emitted from time to time, accompanied by explosions from time to time, but fortunately, the drivers and firefighters handled textbooks in a timely manner and did not cause more serious casualties.
After only one month, on February 18, 2022, a fire broke out in an energy storage project in Jiangxi that had been soaked in rain. The battery compartment burned violently during the storage stage. After the on-site personnel found it, they reported the fire in time, and the firefighters controlled the danger. , the cause of the accident is still under investigation.
The states of the energy storage systems were different when the above-mentioned accidents occurred, but without exception, the shocking "scars" all reflected the inadequacy of the system integration design capabilities and safety design of the accident energy storage manufacturers. With the rapid growth of the energy storage industry, more and more companies have joined in, but some players with uneven technical levels have also brought unstable factors to the industry: the system integration design of some manufacturers is only based on different procurement sources. Brand lithium batteries, energy storage PCS and other equipment are simply piled into containers; the system has not been fully and effectively tested and jointly debugged before delivery, and the protection implementation is not in place, resulting in the final delivery of the entire energy storage system to customers. The product has great performance and safety risks. From the "God's perspective", the design of fire protection system is only a small part of the safety protection measures of the energy storage system, and the integration capability of the energy storage system, post-operation and maintenance, and risk monitoring and management level are even more critical.
Project scale upgrade, protection needs to be more comprehensive
Someone once joked that a single energy storage container may lose several million yuan if it is burned, but if it is not managed well, it may also be an explosive pack. In addition to the loss of equipment burning, the equipment replacement may cause the project to be delayed for 2-3 months and the loss caused by grid connection or outage is also immeasurable.
In 2018, my country's energy storage projects exceeded 100 megawatts, and safety issues began to emerge gradually. In the past year, the scale of domestic energy storage projects has jumped from 100 megawatts to GWh. In the opinion of some people in the industry, the quality or safety of energy storage products also follows Murphy's Law, which is just a probability number.
With the increase in the integration scale of the energy storage system, the number of battery products or electrical equipment doubles, and the potential danger of quality problems also doubles; secondly, the number and levels of batteries in series and parallel increase, the combination of electrical and power electronics is more complex, and energy storage is safe. The difficulty of safeguarding is further increased, and it cannot be completed by simple device stacking and fire-fighting tools.
To effectively ensure the safety of energy storage, it is not only necessary to have strong technical strength in the fields of electrochemistry, electricity, power electronics, etc., but also to have the ability to organically combine hardware and software into a complex system for support. Source control, process protection, end fire protection and other layers of safety management and control ensure the long-term application safety of the energy storage system.
1) Quality management: At present, the cell packaging process of each manufacturer is different, and some are shoddy and even the cell part is directly exposed in the air. If thermal runaway occurs in a single cell, it will quickly spread to the entire container. High-quality materials and manufacturing processes are the premise of product safety. Energy storage system manufacturers need to do a good job in 360° quality control management, especially in key links such as cell raw materials, manufacturing processes, and testing and use to establish professional quality management standards. High-quality materials and advanced craftsmanship are applied to the products. At the same time, to do a good job in the safety management of energy storage in the whole life cycle, it is necessary not only to pay attention to the production and manufacturing links, but also to do a good job in risk prevention in multiple links such as storage, transportation, and installation.
2) Source control: As a common factor causing energy storage fires, manufacturers need to strengthen the detection and prevention of energy storage system cells and arcs. On the one hand, through system monitoring, it can analyze, predict and warn the battery state, and prevent and block thermal runaway from the source; on the other hand, due to the many electrical connections in the energy storage system, under complex operating conditions It may cause arcing phenomenon, which may cause equipment fire. How to carry out arc detection and protection is particularly important for the safety of energy storage systems.
3) Fire protection: On the basis of product quality and source fire protection, the fire protection design of the energy storage system is equally important to the safety of energy storage. How to detect and monitor hidden dangers such as smoke, temperature, and combustible gas through reasonable fire protection design; reduce the loss caused by thermal runaway diffusion through exhaust air pressure relief, explosion-proof design, etc., all require scientific and reasonable design.
4) System design: In the energy storage system, the battery has a strong coupling relationship with PCS, BMS, EMS and other systems. If it is purchased from different brands, and it is commissioned and assembled on site, the strong coupling relationship between the safety guarantees between the systems will be forcibly split and broken. The refined management, linkage protection control, electrical and fire safety cannot be guaranteed, and the long-term operation also brings uncertainty about potential safety hazards and system risks. How to break the information island of each unit of the energy storage system and truly integrate the energy storage system into an organic whole not only tests the technical strength of the manufacturer in electrochemistry, power electronics, electrical and other aspects, but also tests the manufacturer's deep understanding of the energy storage system and The profound accumulation of the operation of the entire energy storage industry.
It can be seen that daily consumers have become accustomed to "shopping around" and "three guarantees after sales", and they should be more cautious in the choice of energy storage products. Energy storage safety is not a single link. It needs to be considered from the entire life cycle of the entire system and power station. Professional system integrators with energy storage core equipment and one-stop service system solutions are obviously the best choice. Only with clear rights and responsibilities and guaranteed after-sales service can the safe and stable operation and revenue of the energy storage power station be guaranteed throughout the life cycle, and the construction of a new power system can be accelerated.
