Worried your lithium battery-powered products will fail in winter? This failure might not be temporary. It could cause permanent damage, leading to costly returns and unhappy customers.
Yes, extreme cold can permanently damage lithium batteries1, but the real danger is charging them below 0°C (32°F). This causes irreversible lithium plating, which reduces capacity and creates safety hazards. Using them in the cold is generally fine, but charging is what causes permanent harm.
I’ve seen many clients, like Michael from the US, get this wrong. They focus on whether the battery works in the cold, but they miss the critical detail that causes permanent failure. It's a costly mistake. Let's break down exactly what you need to know to avoid it.
How cold is too cold for lithium batteries?
You need to define the operating temperature for your product, but the battery specs are confusing. Getting this wrong means your devices could fail unexpectedly in cold weather, damaging your brand's reputation.
For standard lithium-ion batteries, "too cold" for charging is anything below 0°C (32°F). For discharging, performance drops significantly below -10°C (14°F), and most stop working around -20°C (-4°F). These are the critical numbers you need for your product design.
The most important thing to understand is that temperature affects charging and discharging differently. I always emphasize this to my clients because mixing them up leads to product failure.
Charging vs. Discharging: Two Different Rules
Charging a lithium battery is a delicate chemical process. You are moving lithium ions and embedding them into the anode. This process is very sensitive to temperature. Discharging, or using the battery, is simply releasing those ions. It's a more robust process and can tolerate colder temperatures, though not without consequences. The golden rule is this: never charge a standard lithium battery when its cell temperature is below freezing (0°C / 32°F). Using it is okay, but charging it is fatal for the battery's health.
Temperature Limits by Battery Chemistry
Different lithium chemistries have slightly different tolerances, but the rule about charging below freezing is nearly universal for standard cells. Here’s a simple breakdown of what you can expect from the batteries we manufacture at Litop.
| Battery Chemistry | Safe Charging Range | Safe Discharging Range |
|---|---|---|
| Lithium-ion (Li-ion) | 0°C to 45°C (32°F to 113°F) | -20°C to 60°C (-4°F to 140°F) |
| Lithium Polymer (LiPo) | 0°C to 45°C (32°F to 113°F) | -20°C to 60°C (-4°F to 140°F) |
| LiFePO4 | 0°C to 45°C (32°F to 113°F) | -20°C to 60°C (-4°F to 140°F) |
| Litop Low-Temp | -20°C to 45°C (-4°F to 113°F) | -40°C to 60°C (-40°F to 140°F) |
Why Performance Drops in the Cold
Think of the electrolyte inside the battery as a liquid highway for lithium ions. As the temperature drops, this liquid gets thicker, like honey in a refrigerator. This slowdown increases the battery's internal resistance. When you try to draw power (discharge), the high resistance causes the voltage to drop sharply. The device thinks the battery is empty and shuts down. For charging, the slow-moving ions can't get into the anode fast enough. This creates a dangerous "traffic jam" on the surface, which we'll discuss next. For clients with products in cold regions, we offer custom low-temperature batteries2 that use a special electrolyte formula to keep that highway flowing smoothly even in extreme cold.
Does freezing harm lithium batteries?
Your device was left in a freezing car overnight and now it won't work. You are tempted to just plug it in to warm it up, but this could be a fatal mistake.
Freezing (storing a battery below 0°C) does not inherently harm it. The damage happens when you try to charge the battery while it is still frozen. This causes permanent capacity loss and creates serious safety risks. Always warm a battery to above freezing before charging.
This is the single most important insight I share with procurement officers and engineers. The damage from cold charging is not temporary. It is permanent and cumulative. Each time it happens, the battery gets worse until it fails completely.
What is Lithium Plating?
When you try to charge a cold battery, the lithium ions are sluggish. They can't move into their proper home inside the anode structure. Instead, they deposit on the surface of the anode as metallic lithium. This process is called "lithium plating." Think of it like trying to pack a suitcase in a hurry. Instead of neatly folding clothes and putting them inside, you just pile them on top. This pile of metallic lithium does two terrible things. First, it's no longer available to produce energy, so your battery's capacity is permanently reduced. Second, this plating can grow into sharp, needle-like structures called dendrites. If these dendrites grow long enough to puncture the separator between the anode and cathode, they create an internal short circuit. This can lead to rapid overheating and even a fire.
The Role of the Battery Management System (BMS)
The BMS is the brain of your battery pack. Its job is to protect the lithium cells from dangerous conditions like over-charging, over-discharging, and extreme temperatures. A basic BMS will monitor voltage and current. But for a product that might be used or charged in a cold environment, a basic BMS is not enough. You need one with a temperature sensor (NTC thermistor) that measures the cell's temperature. This is the first step. The second, and most critical, step is what the BMS does with that temperature information.
The Most Important Feature: Low-Temperature Charging Protection
This is the feature I tell my customers they must demand from any supplier. A quality BMS with low-temperature charging protection will actively prevent the charger from delivering current if the battery's temperature is below 0°C (32°F). It will simply refuse to charge until the battery warms up to a safe level. Without this feature, your product is a "warranty assassin." You sell it to a customer in a cold climate, they plug it in while it's frozen, and the battery is permanently damaged. They will blame your product for having a bad battery life, and you will face endless warranty claims. This is a non-negotiable feature for any reliable product.
At what temperature do lithium batteries stop working?
Your device is rated for outdoor use, but customers complain it dies in the cold. You need to know the exact temperature where the battery will completely stop providing power.
A standard lithium battery will generally stop working around -20°C (-4°F). While it may still hold a charge, its internal resistance becomes too high to deliver usable power. The device's electronics will register a low voltage and shut down to protect itself.
A "dead" battery in the cold isn't always empty. This confuses many people. The battery might be at 50% charge, but the device shuts down anyway. Understanding why this happens is key to designing a reliable product for cold environments.
The Science of a "Dead" Cold Battery
As we discussed, cold temperatures increase a battery's internal resistance. When your device tries to pull power, this high resistance causes an immediate and severe drop in voltage. This is called "voltage sag." Every electronic device has a minimum voltage it needs to operate, known as the "cutoff voltage." At around -20°C (-4°F), the voltage sag on a standard lithium battery is so extreme that the moment you turn the device on, the battery's output voltage drops below the cutoff level. The device's protective circuits see this low voltage and assume the battery is empty, so they shut the device down to prevent damage. The battery isn't empty, it just can't deliver the power. If you bring that same battery inside and let it warm up, it will work perfectly again.
Available Capacity vs. Temperature
The cold doesn't just make the battery stop working at a certain point; it gradually reduces the amount of energy you can access. The total energy is still there, but you can't get it out. This table gives a rough idea of how much of the battery's rated capacity you can actually use at different temperatures.
| Temperature | Available Capacity (Approx.) |
|---|---|
| 25°C (77°F) | 100% |
| 0°C (32°F) | 80% |
| -10°C (14°F) | 65% |
| -20°C (-4°F) | 50% (but often unusable due to voltage sag) |
Solutions for Extreme Cold Environments
For clients who make devices for ski patrols, arctic researchers, or trucking logistics in Canada, a standard battery is not an option. At Litop, we've developed two primary solutions. The first is our line of custom low-temperature batteries. These use a specialized electrolyte and material formulation that maintains low internal resistance down to -40°C. They can be safely discharged at these temperatures and can even be charged at temperatures as low as -20°C (-4°F). The second solution is an integrated heating system. We can design a battery pack that includes a thin heating foil. The BMS will use a small amount of the battery's own energy to warm the cells to a safe temperature (e.g., above 5°C) before allowing the device to draw power or begin charging. This ensures peak performance and safe charging, no matter the outside temperature.
Conclusion
To summarize, using lithium batteries in the cold is acceptable, but charging them below freezing causes permanent damage. The key is prevention. Always ensure your battery's BMS includes low-temperature charging protection. This simple feature will save you from costly failures and protect your brand's reputation.
