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The Keys to Safe Lithium-Ion Battery Storage

April 5, 2023
The dangers and risks of lithium-ion batteries and how to safely store, charge, and transport them.

Since their launch in the early 1990s, lithium-ion batteries have gradually replaced old technologies due to their high performance and compact design. They are pervasive, with new uses being adopted seemingly every day in a wide range of industries.

While this technology has significant advantages over its predecessors, lithium-ion batteries are not as safe as you might imagine. Incorrectly handling lithium-ion batteries is potentially hazardous. Explosions or fires from lithium-ion batteries can have disastrous consequences with equipment, facilities, and, in the worst case, people being harmed. Because of these risks, it’s critical to understand the dangers of lithium-ion batteries and how to safely store and charge them.

How a Lithium-Ion Battery Works

Understanding how lithium-ion batteries work is a helpful first step in evaluating and mitigating their potential hazards. There are many different types of batteries where lithium is used in a pure or bonded form. However, these lithium cells fall into two categories, secondary or rechargeable cells, and primary or non-rechargeable cells. We’ll focus on the secondary, rechargeable type.

Inside each lithium cell, there's a positive and a negative electrode—the anode and the cathode—with an ion-conducting electrolyte between them. 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 because it stops direct contact between the anode and cathode to prevent 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 electrical work. At the same time, the lithium ions cross through the electrolyte fluid and the separator over to the cathode.

Common Lithium-Ion Battery Issues

Lithium batteries can present a considerable safety hazard if they are incorrectly handled or stored. Some common issues with lithium-ion batteries are fire hazards due to thermal runaway, deep discharge or mechanical deformation.

Thermal runaway can be triggered by thermal loads, 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. Then, 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 that once set in motion, only takes a few minutes until the battery burns and explodes. These thermal runaways are especially dangerous since they are often caused by short circuits that are not apparent upon visual inspection.

If lithium-ion batteries are not used for a long period of time, they can completely discharge. Decomposition of the electrolyte liquid can then lead to the formation of easily combustible gases. If an attempt is made to recharge a discharged lithium-ion cell, the supplied energy can no longer be correctly converted due to insufficient electrolyte fluid. The resulting deep discharge can result in a short circuit or fire.

Lithium-ion batteries can be damaged during handling, including collisions with operating vehicles or being dropped. This can lead to internal short-circuiting and fire within the battery if the cells are deformed as a result. In rare cases, it’s possible that particles that are falsely released into the cell during production can damage them from the inside over time with internal short circuits as a possibility.

Measures for Loss Prevention

With no unified legislation, the storage of lithium-ion batteries poses a dilemma for many companies. Generally, the potential risk associated with lithium batteries increases as the amount of energy stored by the batteries increases and as the number of stored batteries increases. For example, handheld power tool batteries have less energy than a forklift battery but a facility with hundreds of hand tools has more potential risk than a facility with only a few rechargeable tools.

With this in mind, here are some tips for safely storing and transporting lithium-ion batteries; Observe the manufacturer’s instructions, protect battery poles from short-circuit, protect batteries from mechanical deformation, don’t expose to direct and long-term high temperatures including direct sunlight, ensure structural or spatial separation of a least 8 feet (2.5 meters) from other combustible materials when no automatic extinguishing equipment is present, and ensure damaged batteries are immediately removed from storage and production areas.

Safe Storage Solutions

Because of the inherent risks behind lithium-ion batteries, many companies use fire-safe cabinets to store their batteries when not in use. Unlike standard steel storage cabinets, fire-safe cabinets are designed to store hazardous materials, including lithium-ion batteries. They feature solidly welded construction and integrated vents for passive ventilation and are insulated with fireproof, 150-millimeter mineral wool panels (A class material, non-combustible). They also include thermo-dissipative media (class D fire), and visual identification on all sides to alert emergency personnel of contents and hazards.

Fire-safe cabinets can store new, questionable, damaged, defective or end-of-life batteries of all shapes and sizes. The key benefit of these special storage cabinets is that they offer companies up to two hours of fire resistance. This becomes incredibly valuable time in the event of an emergency to clear a facility, alert the proper authorities, and ensure that a fire doesn’t spread. Storage cabinet solutions can also double as rechargeable centers for batteries. This allows the batteries to safely recharge overnight or in off-hours when there are fewer (if any) people present.

As mentioned before, the placement of batteries is critical to safety. This holds true for storage as well. Lithium-ion battery storage cabinets should keep them away from any other combustible material. Storage solutions can also feature transportation bases to allow for quick and safe cabinet removal from a facility should the need arise.

While there are no clear regulations and requirements for safely storing lithium-ion batteries yet, that shouldn’t stop organizations from taking the necessary steps to provide suitable storage and charging solutions for lithium-ion batteries. Failure to do so may result in companies being personally liable by insurers if inadequate fire measures are taken.

In all safety cases, preparation is key. Whether you are currently using lithium-ion batteries or are planning to soon, knowing the dangers they present and having an action plan to mitigate their harm can help you prevent the worst-case scenarios.