13 key safety considerations when choosing a stationary energy storage system-Energy Storage News

2021-11-25 06:21:06 By : Mr. Sndrew Tan

The recent battery incident has become news. Therefore, the topic of safety has once again become a key factor in choosing an energy storage system. Given that there are many alternatives on the market, we believe that a proper search should lead buyers to the safest option. 

When designing Leclanché's new LeBlock modular fixed solution, our engineering team spent years researching and comparing all possible architectures and options. We have refined some learning content here to help you make wise choices when planning your battery installation and to ensure that you have considered the safest option.

In terms of safety, we distinguish between primary safety (what can be done to prevent accidents) and secondary safety (how to better control and manage hazards after an accident). The main safety is directly related to the battery itself. 

There are different types of batteries; each has its advantages. But the most important thing is to consider whether the battery complies with IEC62619. As stated in its title "Secondary batteries and batteries containing alkaline or other non-acid electrolytes-Safety requirements for secondary lithium batteries and batteries used in industrial applications", this standard specifically addresses the safety of batteries.

For modules and racks: Ensure that the battery complies with UL 1973 and IEC 62619 standards. 

Choosing a battery certified by UL9540A means that the system has been tested to simulate a thermal runaway event to check whether the fire will not spread.

As a battery manufacturer with a history of 110 years, Leclanché has extensive experience in battery integration considering mechanical, thermal, electrical and safety constraints. All systems used in marine, transportation or stationary applications undergo an extensive testing and certification process.

The use of safe and standard-compliant components is the mandatory first step to ensure the highest level of safety; however, how the battery is used is also critical. This is why the battery management system (BMS) should ensure that the battery does not exceed its limits. In order to provide this kind of functional safety, the BMS must pass the IEC61508 certification, which is the functional safety standard for electrical/electronic/programmable electronic safety-related systems.

BMS generates a large amount of data, which is read by energy management software (EMS), stored locally and regularly backed up to a secure cloud system. All these data can be used for analysis purposes to detect possible battery misbehavior or deviations at an early stage and optimize system operation.

Separating the energy storage system and separating the battery system in a sturdy enclosure helps prevent the fire incident from spreading to the entire site.

LeBlock is Leclanché's new, safe, modular, scalable, plug-and-play energy storage solution. It aims to simplify logistics and reduce overall costs and carbon footprint.

With LeBlock, the battery module is placed in a compact housing based on powerful container technology. This helps control potential fires in each block.

The case is highly fire-resistant and provides the required thermal insulation function to minimize auxiliary energy consumption to keep the battery at a specific temperature (usually between 20 and 23°C) without being affected by the outside temperature. 

Zoning provides a passive way to improve safety, but there are also some active fire fighting methods. The goal of the fire suppression system is to prevent non-battery fires from spreading to other batteries in the block — to prevent small accidents involving a few batteries from turning into large-scale fires, the consequence of which may be to replace the entire container — or worse, the entire website. The standard fire detection and extinguishing system consists of smoke and heat detection sensors integrated in the aerosol extinguishing system, with automatic activation function.

Personnel safety is the key. Even if a site is safe, employees will work nearby for maintenance and routine system inspections. When a fire or explosion occurs, they may stand next to the battery pack. To protect their safety, the deflagration panel can direct any internal pressure upward. It ensures that people working in the area are protected from side explosions.

LeBlock is equipped with a deflagration panel that complies with NFPA 68.

When an accident occurs, the correct behavior of emergency personnel is not always clear, and may vary depending on the system and local conditions. Therefore, it is very important to develop a site-specific emergency action plan and cooperate with local first responders to provide training.

During an accident, the LeBlock enclosure should remain unopened until its temperature reaches a non-critical range, and the surrounding environment should be monitored and cooled if necessary.

If the EMS, BMS, or any other safety device detects a safety problem or battery abnormality, the battery system must be shut down immediately for a controlled shutdown. It is also important to have a manual "emergency stop" that can be performed by the operator or emergency personnel.

Most batteries are "floating", which means that each polarity is isolated from ground. Advanced insulation monitoring equipment that meets the IEC 615557 standard must ensure that the insulation does not degrade or short-circuit to ground. The granularity of the isolation measurement should be small enough to ensure good measurement accuracy and be limited to a small number of batteries that will be disconnected by the emergency stop function.

In the LeBlock architecture, each Combi Block has its own isolation monitoring, which can automatically detect isolation failures and disconnect the battery before serious problems occur.

In the United States, energy storage systems need to comply with NFPA 855 to mitigate potential hazards. 

In the IEC world, the system must be designed in accordance with the safety requirements of IEC 62933 Part 2, Grid Integrated Energy Enhancement System.

The design and construction of LeBlock have been verified by DEKRA and comply with UL9540, NFPA 855 and IEC62933.

To ensure safety, the system must be equipped with all necessary disconnect devices, such as load disconnect switches, to ensure safe isolation of maintenance operations.

Check compliance with all relevant IEC and UL electrical safety installation standards through advanced fuse systems-especially those that protect devices from short-circuits between polarities.

Lithium batteries are determined to be classified as 9 dangerous goods for transportation. The battery system must be transported by air, sea, rail or road in accordance with UN38.3 standards.

The LeBlock system has passed UN38.3 certification and can be transported to its operating location with full staff. At the end of the system's life, the certification is still valid, and the battery blocks can be transported directly to the appropriate recycling point without any additional packaging.