On March 21st, the "Implementation Plan for the Development of New Energy Storage in the 14th Five-Year Plan" was officially issued, marking the formal transformation of new energy storage from the initial stage of commercialization to large-scale development. However, as mentioned in the four basic principles in the plan, safety is always the bottom line of energy storage development. In the early stage of the development of new energy storage industry, some enterprises lacking core technologies were attracted to enter the industry by policies and subsidies. Irregular and unprofessional practices caused safety problems from time to time, and even caused personal injuries and property losses.
Scar of frequent energy storage accidents is the real reason
In the face of surging market demand and complex application scenarios, global energy storage safety accidents frequently occur, including projects involving some well-known energy storage suppliers. For example, on July 3, 221, a fire broke out in Australia's "Victoria Big Battery", the world's largest battery energy storage project using Tesla Megapack, and it took four days for the fire to go out.
in contrast, in China, three typical energy storage safety accidents have occurred in succession in the past year.
on January 12, 222, a truck loaded with energy storage system suddenly caught fire on the Beijing-Hong Kong-Macao Expressway. Fortunately, the driver found the accident vehicle in time, parked it in the emergency lane and called the police. When the fire rescue workers arrived at the scene, the car was burning violently, and the flames were sprayed out from time to time, with billowing smoke and explosions from time to time. Fortunately, the drivers and firefighters handled it in time like textbooks, which did not cause more serious casualties.
Only one month later, on February 18th, 222, an energy storage project in Jiangxi caught fire, and the battery compartment burned violently during the storage stage. After the scene 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 state of energy storage system was different when the above accidents occurred, but without exception, the shocking "scar" reflected the deficiency of system integration design ability and safety design of accident energy storage manufacturers. With the rapid growth of the energy storage industry, more and more enterprises have joined in, but some players with different technical levels have also brought unstable factors to the industry: the system integration design of some manufacturers only simply stacks lithium batteries, energy storage PCS and other equipment purchased from different brands into containers; The system has not been fully and effectively tested and debugged before delivery, and the protection implementation is not in place, which leads to great performance and safety hazards in the whole energy storage system product finally delivered to customers. From the perspective of "God", the design of fire protection system is only a small part of the safety protection measures of energy storage system, and the integration ability, later operation and maintenance and risk monitoring management level of energy storage system are more critical.
Project scale upgrading and protection need to be more comprehensive
Someone once joked that a single energy storage container may lose several million yuan when burned, but it may also be explosive charges if it is not well managed. In addition to the loss caused by equipment burning, the loss caused by equipment replacement may be delayed for 2-3 months, and the loss caused by grid connection or shutdown is immeasurable.
In 218, China's energy storage projects exceeded 1 MW, and safety problems began to emerge gradually. In the past year, the scale of domestic energy storage projects has jumped from 1 MW to GWh. In the eyes of some people in the industry, the quality or safety of energy storage products also follows Murphy's law, which is only a probability figure.
As the integration scale of energy storage system increases, the number of battery products or electrical equipment doubles, and the potential danger of quality problems also doubles; Secondly, the number and levels of series-parallel batteries increase, the combination of electricity and power electronics is more complicated, and the guarantee of energy storage safety is more difficult, which can not be completed by simple device stacking and fire fighting tools.
in order to effectively ensure the safety of energy storage, it is necessary not only to have excellent 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 as support, so as to achieve safety management and control from source control, process protection, terminal fire protection, etc., and ensure the long-term application safety of energy storage systems.
2) source control: as a common cause of energy storage fire, manufacturers need to strengthen the detection and prevention of energy storage system batteries and arcs. On the one hand, through system monitoring, the state analysis, pre-judgment and early warning of the battery can be achieved to prevent and block thermal runaway from the source; On the other hand, there are many electrical connections in the energy storage system, which may lead to arcing and equipment fire under complex working conditions. How to carry out arc detection and protection is particularly important for the safety of the energy storage system.
3) fire protection: on the basis of product quality and source fire prevention, the fire protection design of energy storage system is equally important for energy storage safety. How to detect and monitor the hidden dangers such as smoke, temperature and combustible gas through reasonable fire protection design; Scientific and reasonable design is needed to reduce the loss caused by uncontrolled thermal diffusion through the design of exhaust, pressure relief and explosion protection.
4) system design: in the energy storage system, there is a strong coupling relationship between batteries and PCS, BMS, EMS and other systems. If the batteries are purchased from different brands and assembled on site, the strong coupling relationship between the security guarantees of the systems will be forcibly broken, and the meticulous management, linkage protection control, electrical and fire safety of the system cannot be guaranteed, and the long-term operation process also brings about the uncertainty of security risks 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 manufacturers in electrochemistry, power electronics, electricity and other aspects, but also tests their deep understanding of the energy storage system and the deep accumulation of the operation of the entire energy storage industry.
It can be seen that daily consumers have become accustomed to "shopping around" and "having three guarantees after sale", so they should be more cautious in the selection of energy storage products. Energy storage safety is not a single link, and it needs to be considered from the whole system and the whole life cycle operation of the power station. The professional system integrator with energy storage core equipment and one-stop service system scheme are obviously the best choice. Only when the rights and responsibilities are clear and the after-sales service is guaranteed, can the safe and stable operation and income of the energy storage power station be escorted and the construction of a new power system be accelerated. (Text: Wei Zhi)