Winter Warning: Why Li-Ion Batteries Don’t Belong in the Cold

Most people understand that lithium-ion batteries shouldn’t be exposed to high heat. But very few realize that cold temperatures can be just as damaging — and even more deceptive.

As we head into winter, this is a critical safety message for schools, districts, families, and workplaces that use battery-powered devices, tools, and equipment.

The Hidden Winter Hazard: Separator Damage

Inside every lithium-ion battery is a thin, porous separator—a film that keeps the positive and negative electrodes from touching. It is the only physical barrier preventing a short circuit.

When batteries are exposed to temperatures below 32°F (0°C):

• The separator can shrink, harden, or crack.

• Internal components contract at different rates.

• Microscopic fractures can form — invisible to the eye.

And here’s what makes this especially dangerous: ❗ Damage done in winter may not show up until spring or summer.

A cracked separator doesn’t always cause an immediate failure. Instead, it becomes a time bomb, waiting for the right conditions — often charging, heavy use, or warm weather — to trigger:

• Internal short circuit

• Overheating

• Off-gassing

• Fire

• Thermal runaway

Common Items at Risk in Winter

If they’re stored in garages, sheds, or cold cars, the following are at risk:

• Power tool batteries

• E-bike, e-scooter, and hoverboard packs

• Portable chargers and power banks

• Lawn equipment packs (leaf blowers, chainsaws, trimmers)

• Drone batteries

• RC car/boat/aircraft batteries

Schools may also see risks with:

• Robotics club batteries

• Science/STEM demo batteries

• Chromebook carts stored in unheated spaces

• Custodial or grounds equipment

Safe Winter Storage Guidelines

To protect the battery — and the building — follow these best practices:

1. Bring them indoors

Store all Li-ion batteries inside at 40–70°F (4–21°C) whenever possible.

2. Never charge a cold battery

Charging a frozen or near-frozen battery dramatically increases the chance of failure. Allow batteries to return to room temperature slowly before charging.

3. Avoid sheds, garages, and unheated storage rooms

Even if the equipment stays there, the battery should not.

4. Create a “Winter Battery Storage Plan”

Schools, districts, and facilities should designate:

• Indoor charging areas

• Temperature-controlled storage

• Signage reminding staff not to store batteries in cold zones

5. Inspect batteries that were exposed to cold

Look for:

• Swelling

• Cracks

• Odd smells

• Discoloration

• Reduced performance

If in doubt, remove from service and dispose of properly.

Why This Matters for K-12 Safety

Cold-weather damage to Li-ion batteries can directly impact:

• Science/STEM labs

• Robotics and engineering programs

• Technology departments

• Grounds and janitorial teams

• Transportation

• Athletics and extracurricular clubs

Schools depend on this technology — and therefore must understand its risks. Duty of Care includes the environment in which we store and use modern energy systems.

Closing

Lithium-ion batteries are safe when handled correctly — and dangerous when they’re not. This winter, take a proactive approach: Bring them indoors. Store them warm. Charge them carefully.

Small steps today prevent major incidents tomorrow.

If your school or district needs help reviewing storage, charging, or winter battery protocols, 

👉 Kevin Doyle Consulting can support you with audits, training, and readiness planning.