Charging lithium batteries: Do you know your duty of care?
Every year, lithium batteries cause about 6,000 fire incidents in Germany. A number of these fires result in considerable property damage. A large part is due to errors during the charging process - which increasingly results in legal disputes between property insurers and policyholders. Find out below what lawyers consider negligent behaviour when charging lithium batteries and which general duties of care you should strictly observe. This will help you increase safety in your business and avoid unnecessary complications in the event of an insurance claim.
Risk of fire increases when charging lithium batteries
Statistics show that the most significant fire risk comes when lithium batteries are charged. This is especially true if a defective lithium battery is connected to a charger and the supplied energy can no longer be converted correctly. A wide variety of events can cause defects. For example, mechanical damage to the lithium battery (dropping, knocking, crushing) or improper storage (thermal stress, exposure to moisture, deep discharge due to excessive storage without regular trickle charging). But even when charging undamaged lithium batteries, things can go wrong: For example, overcharging the battery due to too high a charging voltage or too long a charging time. Exposure to high external heat can also be dangerous. In short, there are many sources of error for the user when charging lithium batteries.
Fire experiment: See what happens when there are charging errors!
See in the video how quickly a lithium fire develops. The DENIOS fire test illustrates the overcharging of a lithium module.
Twelve lithium battery cells were put together in a module for the test. This corresponds to about 2kW of power (an e-car battery has about 100 kW). The lithium module was subjected to an increased charging voltage. When this reaches a value of slightly more than 5V, a reaction occurs, and the lithium battery goes up in fire and smoke cell by cell (thermal runaway). A temperature measurement shows approx—800 °C on the battery.
Your 4 most important duties of care
The subject of legal disputes between property insurers and policyholders is usually whether the user acted negligently when using the lithium battery and thus culpably caused the fire. The following duties of care should be observed in any case, as contraventions are not only dangerous but are also classified as negligence by lawyers:
Only charge lithium batteries with adequate fire protection.
Lithium batteries should never be charged near flammable materials or objects. Also, do not charge lithium batteries in places where high temperatures or sunlight are to be expected. Since the charging process itself generates heat, you should never cover lithium batteries when charging. Especially if you want to charge many devices simultaneously, you should avoid heat build-up in closed rooms or cabinets. This can be problematic during operation, for example, if devices are to be locked up or protected from unauthorized access during charging.
Safe charging of lithium batteries is ensured in professional battery charging cabinets and charging rooms that offer 90 minutes of fire protection on both sides. Unlike standard hazardous materials cabinets, charging cabinets for lithium batteries should have 90 minutes of fire protection from the outside and from the inside. If you want to charge several devices simultaneously in a charging cabinet, it should have technical ventilation to prevent heat build-up inside the cabinet. Setting cabinets with integrated extinguishing systems are also available depending on the operational safety concept. Depending on the application requirements, loading lockers from DENIOS can be equipped with a wide variety of safety components. For example, with additional fire protection and extinguishing technology, vertical F90 partition walls for separate storage and loading, or technical ventilation with upstream sensory temperature control.
Charge lithium batteries only under supervision or monitoring
The charging of a lithium battery should always take place under supervision to be able to react quickly in case of complications. This is, of course, problematic in companies where staff supervision cannot be guaranteed continuously. For example, if staff are not present throughout or during non-operational times such as at night or on weekends.
Technical systems can support you in monitoring charging processes. Professional charging cabinets for lithium batteries have an integrated sensor system (smoke detector and temperature sensor) and sound an alarm if smoke develops. A potential-free contact enables the alarm to be forwarded to the building management system. In models with an integrated aerosol fire suppression system, this is automatically triggered when the critical indoor temperature is exceeded. With the appropriate accessories, different alarms can be differentiated (e.g. different temperature levels) and transmitted directly to your smartphone via the mobile network. Lithium cargo compartments can be individually equipped with state-of-the-art control technology and sensors to continuously record a wide range of parameters. In an emergency, alarms can be triggered automatically and locking or extinguishing systems activated.
Observe the manufacturer's safety instructions.
Manufacturers of battery-operated devices note essential safety instructions in the operating instructions. They note that you may only use the original charger supplied to charge the battery. This is because only this charger is correctly matched to the battery installed in the device. The use of counterfeits is not advisable. Further specifications concern, for example, the temperature window in which the battery may be charged, the maximum charging times that should not be exceeded or cooling times that must be observed after use before setting. Be sure to adhere to the manufacturer's specifications and, if necessary, incorporate them into your operating instructions.
Be cautious if you do not know the condition of the battery.
You should not charge a lithium battery carelessly if you do not know any previous damage. For example, this may be the case if you have bought or rented used equipment. However, devices that several employees use can also harbour corresponding risks. Before each charging process, you should visually check a lithium battery for external damage (e.g., cracked, dented or inflated casing). The lithium battery must never be connected to a charger if damage is detected. Operational incidents involving lithium battery damage should be reported, and the battery should subsequently be inspected. We recommend that these preventive measures be recorded in an operating manual and that employees be sensitized accordingly. All previously mentioned care duties should also be observed to exclude residual risks.
Safe charging of lithium batteries with charging cabinets and charging compartments from DENIOS