Lithium-Ion Battery Labels: What Every Symbol Means

Why Lithium-Ion Battery Labels Matter

Every lithium-ion battery you buy or use has a label printed or stuck on it. Most people glance at it and move on, but those few lines and symbols actually tell you if the battery is safe, genuine, and legal to use or ship. Ignoring the label can get you into trouble with customs, airlines, or even cause safety issues. Understanding what’s written saves time and headaches.

Basic Information on the Label

At the top or in the biggest font you’ll usually find the brand, model number, and the words “Lithium Ion Battery” or “Li-ion”. Some labels also say “Rechargeable Li-ion Battery” to make it clear it’s not a primary cell. The model number is what you need when you search for a replacement or check compatibility.

Capacity Rating (mAh or Wh)

Capacity is shown as milliamp-hours (mAh) or watt-hours (Wh). For small cylindrical cells like 18650 or 21700 it’s usually in mAh (e.g., 3500 mAh). For power banks and laptop packs it’s common to see both mAh and Wh. A real battery never exaggerates capacity more than 5–10 % above the best cells available at that time. If a 18650 claims 9900 mAh, it’s fake.

Nominal Voltage and Voltage Range

Most lithium-ion cells have a nominal voltage of 3.6 V or 3.7 V. The label often shows the full range: “3.6 V – 4.2 V” or “3.7 V nominal, max 4.2 V”. This tells chargers and devices the safe charging limit. Some cobalt-free LFP cells are marked 3.2 V nominal.

Battery Chemistry Code

Real manufacturers print a short code that shows the exact chemistry: – INR = NMC (Nickel Manganese Cobalt) – ICR = LiCoO₂ (Cobalt) – IFR = LiFePO₄ (LFP) – NCA, NMC, etc. This matters when you match cells for a pack or choose the right charger.

Manufacturing Date and Batch Code

Freshness counts. Look for a date code like “2025-03” or “25C”. Lithium-ion batteries slowly lose capacity even when stored properly, so anything older than 2–3 years is already degraded before you start using it.

Common Safety Symbols You’ll See

These are the most frequent icons on lithium-ion battery labels:

• Crossed-out trash can with Li-ion below → do not throw in household waste
• Flame inside a circle with a line through it → no incineration
• Exploding battery icon → risk of fire or explosion if mishandled
• Keep away from children symbol

UN38.3 Test Mark

Any lithium-ion battery shipped by air must pass UN38.3 tests. The label (or the box) will have the UN38.3 logo or simply the text “UN38.3 Tested”. Without it, airlines and many forwarders will refuse the shipment. For loose cells it’s usually on the label; for finished packs it can be on the outer box.

Transport and Shipping Symbols

You’ll see one of these two labels since 2025 rules changed a bit:

• Class 9 hazardous goods diamond with “UN3480” (loose cells) or “UN3481” (batteries in equipment)
• The newer lithium battery handling label (red border, battery + flame icon) for excepted packages under 30 % state of charge

If you ship batteries yourself, the exact label you need depends on watt-hours and quantity.

Recycling and Disposal Symbols

Almost every label has the crossed-out wheeled bin and sometimes “Li-ion” underneath. It means the battery must go to a certified recycling point, not regular trash. Some countries fine companies heavily for wrong disposal.

CE, FCC, RoHS and Other Compliance Marks

– CE → meets European safety standards
– UKCA → same for UK after Brexit
– RoHS → no hazardous substances above limits
– FCC → electromagnetic compatibility (mostly on packs with protection circuits)
Missing marks in certain markets can block customs clearance.

Warning Texts You Should Never Ignore

Typical warnings printed in tiny font:

• Do not short circuit
• Do not disassemble
• Do not expose to temperatures above 60 °C
• Stop use if battery swells or leaks
• Use only specified charger

These are not just legal text – they describe real ways people damage batteries and start fires.

How to Spot Fake or Wrong Labels

Quick checks anyone can do:

• Capacity too good to be true (e.g., 5000 mAh in 18650 size)
• No UN38.3 mark on cells sold as “brand new”
• Printing is blurry or misaligned
• No date code or the date is years old
• Wrong voltage (claims 3.7 V but chemistry code shows LFP)

If more than one thing looks off, walk away.

Quick FAQ about Lithium-Ion Battery Labels

Q: Can I cover the label with my own sticker?
A: Never cover the original label completely. Customs and safety inspectors need to see it.

Q: My power bank has no Wh rating, only mAh. Is that legal?
A: In many countries now required to show Wh. Old stock is still allowed to be sold, but new production must have both.

Q: What does “Limited Charge 30 %” sticker mean?
A: The battery was shipped at 30 % or less state of charge to qualify for less strict air transport rules.

Q: Do button cells need the same labels?
A: Small coin cells under 0.3 g lithium are usually exempt from most labeling rules.

Next time you pick up a lithium-ion battery, take ten seconds to read the label. It tells you almost everything you need to know about safety, performance, and whether you can actually take it on a plane or ship it to your customer.