Lithium battery fires and accidents are on the rise and present risks that can be mitigated if the technology is well understood.
• Secondary (rechargeable) lithium batteries are comprised of rechargeable cells containing an intercalated lithium compound for the anode and cathode. Rechargeable lithium batteries
are commonly referred to as “lithium-ion” batteries.
Single lithium-ion batteries (also referred to as cells) have an operating voltage (V) that ranges from
3.6–4.2V. Lithium ions move from the anode to the cathode during discharge. The ions reverse
direction during charging. The lithiated metal oxide or phosphate coating on the cathode defines the
“chemistry” of the battery.Lithium-ion batteries have electrolytes that are typically a mixture of organic carbonates such as
ethylene carbonate or diethyl carbonate. The flammability characteristics (flashpoint) of common
carbonates used in lithium-ion batteries vary from 18 to 145 degrees C.
Other than cell phones and tablets, most portable electronic/electrical devices operate above the normal operating voltage of single lithium-ion batteries (3.6–4.2V). For such devices, numerous cells
connected in packs provide the desired voltage and capacity. Connecting cells in parallel increases pack amperage and discharge capacity while connecting cells in series increases pack voltage. As an example, a 24V lithium-ion battery pack typically has six cells connected in series.
Many battery packs have built-in circuitry used to monitor and control the charging and discharging characteristics of the pack. As an example, circuitry will automatically manage the charging when the
pack cells reach 4.2V and/or if the temperature exceeds a preset value. The circuits will shut down the pack if the cells discharge below a preset value (e.g., 3.3V per cell).
The cylindrical cell (identified by “18650”) is similar in size and shape to an AA battery. It is the
“workhorse” of the lithium-ion battery industry and is used in a majority of commercially available battery packs.
BEST STORAGE AND USE PRACTICES
Procurement
• Purchase batteries from a reputable manufacturer or supplier.
• Avoid batteries shipped without protective packaging (i.e., hard plastic or equal)
• Inspect batteries upon receipt and safely dispose of damaged batteries.
Storage
• Store batteries away from combustible materials.
• Remove batteries from the device for long-term storage.
• Store the batteries at temperatures between 5°C and 20°C (41°F and 68°F).
• Separate fresh and depleted cells (or keep a log).
• If practical, store batteries in a metal storage cabinets.
• Avoid bulk-storage in non-laboratory areas such as offices.
• Visually inspect battery storage areas at least weekly.
• Charge batteries in storage to approximately 50% of capacity at least once every six months.
Chargers and Charging Practice
• Never charge a primary (disposable lithium or alkaline) battery; store one-time use batteries
separately.
• Charge or discharge the battery to approximately 50% of capacity before long-term storage.
• Use chargers or charging methods designed to charge in a safe manner cells or battery
• Disconnect batteries immediately if, during operation or charging, they emit an unusual
smell, develop heat, change shape/geometry, or behave abnormally. Dispose of the
batteries.
• Remove cells and pack from chargers promptly after charging is complete. Do not use the
charger as a storage location.
• Charge and store batteries in a fire-retardant container like a high quality LiPo Sack when
practical.
• Do not parallel charge batteries of varying age and charge status; chargers cannot monitor
the current of individual cells and initial voltage balancing can lead to high amperage,
battery damage, and heat generation. Check voltage before parallel charging; all batteries
should be within 0.5 Volts of each other.
• Do not overcharge (greater than 4.2V for most batteries) or over-discharge (below 3V) batteries.
Handling and Use
• Handle batteries and or battery-powered devices cautiously to not damage the battery casing or connections.
• Keep batteries from contacting conductive materials, water, seawater, strong oxidizers and strong acids.
• Do not place batteries in direct sunlight, on hot surfaces or in hot locations.
• Inspect batteries for signs of damage before use. Never use and promptly dispose of damaged or puffy batteries.
• Keep all flammable materials away from operating area.
• Allow time for cooling before charging a battery that is still warm from usage and using a battery that is still warm from charging.
• Consider cell casing construction (soft with vents) and protective shielding for battery research and experimental or evolving application and use.
Disposal
• Dispose of damaged cells and cells that no longer hold a substantial charge. To check the general condition of your cells, charge them, let them rest for an hour, then measure the voltage. If your cells are close to 4.2V, the cells are in good condition.
• Dispose of used batteries by taking them to an e. Media bin (if less than five pounds
Lithium battery system design is a highly interdisciplinary topic that requires qualified designers.
Best practices outlined in IEEE, Navy, NASA, and Department of Defense publications should be followed. Battery selection, protection, life, charging design, electric control systems, energy balance of the system, and warning labels are examples of topics that require thoughtful consideration.
Systems designed for mobile applications should apply best practices to ensure appropriate safeguards are in place. Designs should include a hazard assessment that identifies health, physical and environmental hazards, with all hazards appropriately mitigated through engineering and administrative controls. Examples of baseline criteria for system design include:
• Failure scenarios, including thermal runaway should be considered during design and testing so that a failure is not catastrophic.
• Maintain cells at manufacturers’ recommended operating temperatures during charging or discharging.
• Size/specify battery packs and chargers to limit the charge rate and discharge current of the battery during use to 50% of the rated value (or less).
• Practice electrical safety procedures for high capacity battery packs (50V or greater) that present electrical shock and arc hazards. Use personal protective equipment (PPE) and insulate or protect exposed conductors and terminals.
EMERGENCIES
Follow these steps if there is evidence of a battery malfunction (e.g., swelling, heating, or irregular odors). Use personal protective equipment, such as gloves, goggles/safety glasses and lab coat.
• If batteries are showing evidence of thermal runaway failure, be very cautious because the gases may be flammable and toxic and failure modes can be hazardous.
• Disconnect the battery (if possible).
• Remove the battery from the equipment/device (if possible).
• Place the battery in a metal or other container away from combustibles.
• Contact the local fire department or EH&S at 206.616.5530 and ask for advice on how to
proceed.
• Complete an Online Chemical Waste Collection Request or call EH&S at 206.616.5835.
• If a lithium battery fire occurs, use a CO2 (Class BC) or dry chemical (Class ABC) fire extinguisher. These are common to campus buildings. Lithium batteries do not have actual lithium metal so do not use a Class D fire extinguisher.
Post time: Mar-10-2023