Energy storage system safety classification being studied

The responsibility for fire design review and acceptance was transferred from the former public security fire department to the housing and construction department in 2019. Regarding the fire design review and acceptance of new construction projects such as energy storage power plants, we surveyed about 6-7 provinces' housing and construction departments in June and July, and all of them are following up on the fire review and acceptance of energy storage power plants.

There are two aspects of confusion: on the one hand, the acceptance of large-scale containerized energy storage power stations; on the other hand, the acceptance of station-type energy storage power stations. The confusion lies in: first, the national standard 51048 in the revision, the standard has not come out, the lack of standards and norms, to the provinces and cities in the acceptance process brings difficulties. At the same time, we also understand that many provinces and cities are preparing local design review or acceptance standards and technical guidelines, and our institute is also actively participating in the preparation of this work.

Our institute has also done a lot of research on fire safety solutions for energy storage power stations, including policy support. Among them, the safety aspect we also think is a dynamic process. First of all, the safety of the whole industrial chain needs to be emphasized from the preliminary design to the final operation and management. The case of the bus mentioned in the report just now is quite good. In the course of our research, we also found that buses are also equipped with lithium batteries, and at the same time, there is an early warning system. According to my understanding, the bus warning alarm frequency is quite a lot, but the frequency of real combustion is not too much, so we must consider multi-level warning or very early warning in the energy storage system to achieve the goal of early prevention and control.

Secondly, in terms of safety, we should pay active attention to the direction of the new battery or energy storage system, one invention is the solid-state battery mentioned earlier, and the other invention is a new cooling method - liquid cooling. There are different forms of liquid cooling, such as full immersion liquid cooling program, the effect may also be good, this may also be a direction to improve safety.

Third, in order to allow lithium batteries to be used safely in multiple fields and scenarios, our institute is working with relevant organizations to study the classification of safety levels of energy storage systems. From the core, system, warning, protection, management of the five dimensions to evaluate the level of energy storage system, to give it a safety rating. Different levels may have different safety measures or safety requirements in the future.

How can energy storage fire protection system really play a due role?

Zhuo Ping: Today, listening to this energy storage safety and risk prevention and control will be particularly encouraged by the industry inside the big names, are talking to us about fire and safety issues, from the battery's intrinsic safety, energy storage modules to the safety of the system integration design, these are constantly progressing. To the piece of fire rescue, including fire products, the current situation from the earliest time we carried out research on energy storage found that the targeted fire alarm products and fire extinguishing products standards are missing. That is to say, energy storage systems are currently installed in the fire products, but it is not yet clear that the fire products really play a role in the effect. The National Energy Board's latest release of "twenty-five requirements to prevent power production accidents (draft)", put forward the fire extinguishing system should meet the extinguishing module-level battery fire and 24h non-reignition, personal understanding is that I hope to give the energy storage fire protection products to a fire suppression based on the support. For example, energy storage systems applied in the fire alarm system, fire extinguishing system can be tested on a unified platform, and the results of the test has credibility, this is a very important thing.

We can all see that electric cars and electric buses are two types of electric transportation in the country's new energy development is relatively fast, but the fire of electric cars according to the data released by the Ministry of Emergency Management in the first quarter of this year reached a level of almost 7 average daily. But why haven't there been so many fires in electric buses, represented by electric buses? The actual problem is that we have researched and formulated special testing standards for fire warning and alarm products as well as fire extinguishing products for electric buses, and we have also carried out technical appraisal of such fire protection products. There are some qualified fire protection products applied to electric buses, so now fires in electric buses are basically prevented and controlled.

I believe that so many people are now concerned about the safety of energy storage, and once the standards for fire protection products are established, the fire warning and alarm capability and fire extinguishing capability of fire protection products will be able to reach a relatively reliable level. If the place of application of the energy storage system can effectively realize the fire warning, fire alarm, and finally be able to realize the fire can be controlled, it will be more places of application, and the application will be more extensive, it will not be like the vast majority of the present are containerized use.
Just now you also said the container and station type energy storage power station. At present, we generally refer to the battery container as a structure, and the station type is executed in accordance with the building. Just now you have made a very good point, we have done a lot of work from the system level, from the containerized level, but there are still some problems in terms of station-type design. One is the station-type energy storage power station, because it involves the whole room, the whole building fire alarm system design and fire suppression system design, and the container is not a completely equivalent concept. Secondly, in the future, more household energy storage products will also enter the occupied or densely populated places, so that the fire design involves many other complex elements need to be considered.
Energy storage process safety should attract more attention

A lot of people focus on fire, battery thermal runaway, energy storage plant in the construction, implementation process, of course, the fire is the most important and largest, in addition to the fire there are also electrical modules, such as due to the battery inconsistency triggered by the failure. In addition to batteries there are also PCS, transformers, which can likewise fail, thus affecting the normal operation of the power station. In addition to fire and electrical there is also dust, which can have an impact on reducing insulation or heat dissipation, etc. There are also simple wiring harnesses, including wiring harness placement, wiring harness fire treatment and so on. Just now Sun academician to, failure is mainly three aspects, one is battery safety, one is process safety, one is fire safety. The formation of energy storage power plant design and development, more attention is paid to the process safety.

The first thing is to establish a set of special needs of the energy storage power station, for example, what is the current and voltage, over-voltage and over-current charging in the charging process. With the development of artificial intelligence technology now, let's say the establishment of valves, and toxic gases in the battery compartment, but also includes the electric cell, are the selection of special data. With the data, how to carry out high-energy warning? We all know that failure occurs one in the early stage, one in the developmental stage, and one in the dangerous stage. According to the trend to make early warning. We, Xinyuan Smart Storage, have done a lot of practical work in this area, including other equipment in addition to electric cores, such as air conditioners, fans, transformers and so on. Our early warning can achieve good results if handled reasonably.

In general, one is with the technology, one is with the growth of experience, there are still many problems in the integration of power plants, such as fire protection. In addition to standards there are management, operational norms, institutional aspects and so on. I believe that the results will get better and better with continuous development.