Lithium battery life cycle fire risk analysis

Lithium-ion batteries have an irreplaceable role in the field of consumer electronics and new energy vehicles because of their high energy density and long service life. At the same time, however, lithium-ion batteries have a high risk of fire and are prone to fire and explosion. According to incomplete statistics, there were 37 fire accidents related to the lithium battery industry in 2016, which were distributed in the production, transportation, application and recycling of lithium-ion batteries.

Therefore, the author conducts preliminary fire risk analysis for each stage of the life cycle of lithium-ion batteries, and shares the main contents of the lithium battery loss prevention guide VdS3103 issued by the German Insurance Association GDV and the German professional safety association VdS.

Risk in the production process

The production of lithium ion batteries is a chemical and mechanical process. The electrolyte inside the battery is a flammable liquid and the electrode is a combustible material. After the battery is made, electrical testing is required. During the formation phase (ie, the first charge is activated), there is a possibility of thermal runaway fire due to internal short circuit, liquid leakage, and overcharge. The high temperature aging stage of the battery with various temperatures also poses a fire hazard.

Risk in storage

Both production areas and storage warehouses have the potential to store semi-finished or finished products in a centralized manner. If the shelf spacing is small and the storage density is high, once the fire occurs, the fire spreads quickly and is prone to explosion. The German insurance industry association GDV and the German professional safety association VdS released the announcement of the safe storage of lithium batteries in May 2016. The batteries were classified according to their capacity, and relevant safety guidelines were given. The stack height, area, spacing and fire system settings were proposed. Wait for the request. This article will discuss the details in detail later.

Risk during transportation

Lithium batteries are mostly produced in Asia, and the transportation process is complicated, with at least one-third being transported by air. In the past 10 years, the FAA FAA recorded a total of 121 accidents involving batteries (including crashes), mostly caused by lithium batteries. Since April 2016, ICAO ICAO has banned passenger aircraft from transporting lithium-ion batteries (UN3480), except for lithium batteries in electronic equipment carried by crew members and passengers.

Risk during use

Lithium batteries are safe under normal conditions of use, but if the battery is overcharged, short-circuited, bumped, or ingress, there is a risk of fire and explosion. If it cannot be effectively controlled, it may even cause the electric vehicle to burn, which poses a threat to the safety of passengers.

It is also possible to ignite the charging pile during charging. The energy storage battery is centrally set and has a large capacity. If the fire is caused, the equipment will be powered off or burned and cannot be operated.

Risk during recycling

The types of batteries recovered are various, the status is unknown, and may be damaged or defective. It is easy to catch fire due to short circuit, liquid leakage, water ingress, etc., and more safety measures should be taken.

lithium battery Loss Prevention Guide VdS3103

In May 2016, the German Insurance Association GDV cooperated with the German professional safety association VdS to release the lithium battery loss prevention guide VdS3103. The guide provides recommendations for loss prevention for the storage and supply of lithium batteries in production and storage areas. The author translated and summarized the focus of the guide. Now share the following.

In this guide, lithium batteries are classified into lithium metal batteries (primary batteries/primary batteries) and lithium ion batteries (secondary batteries), and are classified into low-capacity, medium-capacity, and high-capacity batteries by capacity and weight.

Taking a common lithium ion battery as an example, a battery having a capacity of 100 Wh or less is a low capacity, and a battery having a weight of 100 Wh or more but a weight of less than or equal to 12 kg is a medium capacity, and a capacity of 100 Wh or more and/or a weight of more than 12 kg is a high capacity.

Lithium battery life cycle fire risk analysis and loss prevention guide

General security rules

The following safety rules should be observed at all times:

Follow the manufacturer's instructions for use and product technical data sheet

Prevent external short circuits (such as avoiding shorting of battery terminals)

Prevent internal short circuits (avoid mechanical damage)

Do not expose directly to high temperature or heat source radiation, such as sunlight.

Keep at least 2.5 meters from other combustible materials in areas where automatic fire suppression systems are not installed.

Immediately remove damaged or defective batteries from production and storage areas, temporarily placed outside of a safe distance, or stored in a separate area where the fire protection system is installed.

Only batteries tested in accordance with UN38.3 can be stored normally (except for prototypes after risk assessment).

Specific security rules

Low capacity battery

Just follow the general safety rules. If the amount of storage in an area is too large (more than 7 cubic meters or more than 6 European pallets), refer to the medium capacity battery.

Medium capacity battery

The medium-capacity battery storage area must be at least 5 meters away from other areas, or the structure should be fire-retardant. Avoid mixing with other products that will act as combustion improvers. The storage area should be monitored by a fire detection alarm system that is connected to a monitored monitoring center. If using a fire suppression system, consider using the recommended fire extinguishing agent in the product data sheet. If the amount of storage in an area is too large (covering an area of 60 square meters or more and/or storing more than 3 meters), refer to the high-capacity battery.

High capacity battery

There is currently no reliable information for adequate protection of high-capacity batteries. Therefore, security measures should be developed in consultation with insurance companies based on the specific circumstances of each case.

Possible measures include:

Isolate and limit the quantity

Store in a separate fire-retardant area or maintain a safe distance (above 5 meters)

Automatic fire extinguishing system

Supply in the production area

If a battery needs to be stored in the production area, the following conditions should be met:

Minimize the amount of storage (store only the daily usage)

Prepare adequate fire extinguishing equipment (fire extinguishers, fire hydrants)

The page contains the contents of the machine translation.