JM Lithium Battery Series 30：What happens if lithium-ion battery is not used for long time?
Table of Contents
Lithium-ion batteries are everywhere—from smartphones and laptops to EVs and portable power stations. They’re popular because they hold more energy, are lighter, and lose charge slower than older battery types. But many people don’t realize that leaving a lithium-ion battery unused for months can cause permanent damage. Whether you’re storing a spare battery or a seasonal EV, inactivity can hurt its performance, safety, and how long it lasts.
1. What Happens When Lithium-Ion Batteries Sit Unused
The biggest change is lost capacity. A lithium-ion battery left idle for 6 months or more may only hold 80-90% of its original charge, and this gets worse over time. It will also charge slower and run out of power faster because its internal resistance goes up. In extreme cases, the battery can die completely. If it discharges too much (below 2.5V per cell), it might not recharge at all. Rarely, deep discharge can cause swelling, leakage, or overheating—especially with low-quality or damaged batteries.
2. Why Inactivity Hurts Lithium-Ion Batteries
All lithium-ion batteries lose charge naturally, even when not in use. High-quality ones lose about 1-2% per month, but heat or age speeds this up. When the battery’s charge drops too low, its internal chemicals break down. A thin protective layer inside the battery (called the SEI layer) wears out, and the materials that store energy change shape. This makes it harder for the battery to hold and release power.
3. How Lithium-Ion Compares to Other Batteries
Here’s a quick look at how different batteries hold up when unused:
| Battery Type | Capacity Loss After 1 Year | Self-Discharge Rate | Risk of Permanent Damage |
|---|---|---|---|
| Lithium-Ion | 10-20% | 1-2% per month | High (if charge drops too low) |
| Lead-Acid | 30-40% | 5-10% per month | Moderate (can often be reconditioned) |
| Nickel-Cadmium (NiCd) | 20-30% | 15-20% per month | Low (more resistant to deep discharge) |
Lithium-ion batteries lose charge slower than lead-acid or NiCd batteries, but they’re more sensitive to deep discharge from inactivity. Unlike lead-acid batteries, lithium-ion damage from being left dead is usually permanent.
4. Simple Tips to Store Lithium-Ion Batteries
To avoid damage during storage, follow these easy steps:
- First, charge the battery to 40-60% before putting it away. This keeps it stable without straining it.
- Second, store it in a cool, dry place—ideally 15-25°C (59-77°F). Heat above 30°C (86°F) speeds up damage, and freezing temperatures can hurt it too.
- Third, check it every 3-6 months and recharge it back to 40-60%.
- Finally, never store it fully charged or fully discharged—both states cause unnecessary stress.
Lithium-ion batteries are reliable, but they need proper care during inactivity. Leaving them unused for months leads to lost capacity, slower charging, and safety risks, all from natural discharge and internal wear. By following simple storage rules—partial charge, cool storage, and regular checks—you can keep your batteries in good condition for years. Whether you’re a consumer with spare gadgets or a business managing EVs, knowing how to store lithium-ion batteries saves you money and avoids frustration.
