Safe Storage of Lithium-Ion Batteries
Lithium-based batteries offer high performance with a compact design. These advantages mean they are being increasingly used in electronic devices and vehicles.
Alongside these advantages, this technology also poses safety risks.
In order to evaluate the potential hazards associated with lithium batteries, understanding how they work can be very helpful. There are many different types of batteries where lithium is used in a pure or bonded form. Lithium cells are divided into primary (non-rechargeable) and secondary (rechargeable) cells. A battery pack is made up of several cells depending on capacity.
Each lithium cell has a positive and a negative electrode, the anode and the cathode. Between them, there is an ion-conducting electrolyte. This ensures the transport of the lithium ions between the electrodes during the charging and discharging processes. The separator is also an important part of the device. It stops direct contact between the anode and cathode and therefore prevents a short circuit.
During the discharging process lithium ions and electrons are released on the anode side. The electrons flow through the external circuit and perform the electrical work. At the same time, the lithium ions cross through the electrolyte fluid and the separator over to the cathode.
Lithium batteries can present a considerable safety hazard if they are incorrectly handled or stored. In addition, factory defects or contamination can pose safety risks. Deep discharge, fire, chemical reactions – each individual situation means a risk for workers, companies and the environment.
Some common issues with lithium-ion batteries are:
Fire hazard due to thermal runaway
If cells overheat there is a risk of thermal runaway. Thermal runaway can be triggered by many things, from thermal loads to mechanical damage or factory defects. This is an exothermic reaction, which can ignite the stored lithium and cause an extremely hot fire that produces its own oxygen.
High levels of heat energy vaporize the electrolyte fluid, creating additional heat and combustible gases. If the ignition temperature for a gas is exceeded, it will ignite and set fire to the battery. Thermal propagation can create a devastating chain reaction. Once set in motion, it only takes a few minutes until the battery will burn and explode.
Fire hazard due to deep discharge
If lithium-ion batteries are not used for a long period of time, they can completely discharge. Decomposition of the electrolyte liquid can lead to the formation of easily combustible gases. If an attempt is made to recharge the deeply discharged lithium-ion cells, the supplied energy can no longer be correctly converted due to the lack of electrolyte fluid. Deep discharge can result in a short circuit or fire.
Fire hazard due to mechanical deformation
When handling lithium-ion batteries, there is always a risk of damaging them. Collisions with operating vehicles or a fall on hard ground are just a few examples. If cells are deformed as a result, this can lead to internal short-circuiting and fire of the battery. In rare cases, it is possible that particles that are falsely released into the cell during production can damage them from the inside over time. Here, too, internal short circuits can occur.
When a lithium-ion battery burns it generates its own oxygen. Only special suppression powders and granules are suitable for combating Class D fires, which are classified by the presence of burning metals.
It is recommended to stock suppression powder or granules in sufficient quantities as a preventative measure. By covering the fire load with granules, oxygen is displaced and separated from the fuel. Like glass, the granules melt at a certain temperature. The granules absorb heat in the form of melting energy, cooling the fire. Additionally, an impermeable envelope is formed over the fire load. A reaction with oxygen is effectively prevented.
The outbreak of fire is not the only risk involved with lithium batteries. If there is a reaction, there is a risk of hazardous substances such as hydrochloric or hydrofluoric acids being released from inside the cell. This may appear in the form of vapor, which could injure workers through skin contact or inhalation.
The storage of lithium-ion batteries poses a dilemma for many companies because there is no unified legislation. To avoid and limit damage, safety measures can be taken depending on the individual case. Generally, the potential risk associated with lithium batteries increases as the amount of energy stored by the batteries increases, and as the number stored increases.
Keep these tips in mind when storing or transporting lithium-ion batteries:
· Observe manufacturer’s instructions (technical product datasheets)
· Protect battery poles from short-circuit
· Protect from mechanical deformation
· Do not expose to direct and long-term high temperatures or heat sources (including direct sunlight)
· Ensure structural or spatial separation (min. 2.5 m) from other combustible materials, if there is no automatic extinguishing equipment present
· Ensure damaged batteries are removed immediately from storage and production areas (store at a safe distance or in a fire-rated area until they are disposed of)
We are happy to support you in selecting the best combination for your needs. For over 30 years, we have provided expert advice on the safe storage of hazardous goods and offer the highest levels of fire protection.
Based on the proven technology of our hazardous substance cabinets, a powerful system was developed for the special hazard potential of storing lithium batteries. With double-sided fire protection, the SafeStore fulfills the increased requirements that in particular, property insurers place on the storage of lithium batteries.
Two tried and tested sizes with three to six storage levels provide tailored capacity for smaller and larger amounts of medium-power batteries. Height-adjustable heavy duty grid floors (397 lbs load capacity) provide the necessary flexibility. A tested, liquid-tight spill tray (powder-coated sheet steel) is used to absorb any leaking sparks from burning batteries.
The SafeStore has these basic features:
90 minutes fire protection
Stable, high-quality and scratch-resistant outer shell
Lockable doors by means of profile cylinders
Integrated lock status indicator (red / green)
Integrated transport base with optional plinth panel