Verify Genuine Battery Cells from Chinese Suppliers
Reminder: Outer wraps and stickers can both be faked. Appearance alone cannot give a 100% verdict. Many refurbished cells are re-wrapped and given a reprinted QR code.
1. Appearance and code pre-screening (no tools needed)
QR code / laser code check — Genuine cells from major manufacturers (CATL, EVE, Panasonic, Samsung, etc.) are laser-etched into the metal shell, not added later as a sticker QR code. Every cell QR code and serial number is unique, and scanning it should return the brand, model, capacity, batch and production date.
Red flag — A sticker QR code, a scan that returns no information, several cells with exactly the same QR code pattern, or a code that has been ground down all point to a high probability of refurbishment or counterfeiting.
Terminal and tab inspection — Brand-new A-grade cells have flat terminals and neat original laser welds. Cells pulled from used packs and refurbished show welding marks and grinding or polishing marks (sellers polish to hide old weld spots). Under a magnifier the weld seam looks rough and uneven.
Shell and dimensions — The wrap is smooth, without wrinkles, bulges or dents. Measure thickness and diameter with calipers; genuine cells of the same model show extremely small dimensional deviation. Bulging and inconsistent thickness basically mean old cells.
Weight comparison — Weigh cells on a precision electronic scale. Genuine cells of the same model have a fixed standard weight. Fakes and refurbished cells usually run light (not enough active material inside). Compare against a cell you already know to be genuine.
2. Traceability and document verification (a must when purchasing)
Ask the supplier for the original factory batch test report — The code on the report must match the cell QR code one to one, and must include capacity, internal resistance, self-discharge and OCV (open circuit voltage).
Contact the cell brand's official customer service — Submit the serial number or batch number for back-end verification. Note that not every brand opens up QR verification; some can only be checked manually.
Reasons to walk away — No original factory report, screenshots only, or codes that do not match. All of these are basically doubtful.
3. Instrument testing (the core step that separates overstated specs from refurbished cells)
Equipment needed: internal resistance tester, capacity grading cabinet
Open circuit voltage (OCV): brand-new cells from the same batch show very high static voltage consistency, so the voltage spread is small. Used cells taken from packs show a large spread.
AC internal resistance: genuine cells of the same model have internal resistance inside a fixed range. Refurbished or poor-quality cells run high, and internal resistance across the batch is scattered and widely different (this is very hard to fake).
Capacity grading test: charge fully, then discharge at constant current, and check whether measured capacity is close to nominal capacity. Many fake cells print a large capacity on the shell while the real discharge capacity falls far short.
Self-discharge test: charge fully and let the cells rest for 7~14 days, then measure voltage drop. Old cells self-discharge noticeably more and lose voltage fast.
4. Quick red-flag checklist
- B grade is not the same as counterfeit — B-grade cells are genuine cells rejected by the original factory for failing to meet standard. Their parameters are poor and they are not counterfeit, but they are not brand-new A-grade cells either.
- Appearance alone can be faked — Wrapping, inkjet printing and polishing of terminals can all be done. Internal resistance plus capacity consistency are the indicators that refurbishment finds very hard to disguise.
- Safety reminder — Do not take cells apart yourself; there is a risk of fire and explosion.
5. Simple priority summary
- Scan the code and check the serial number (brand official traceability)
- Compare appearance, terminals, weight and dimensions
- Quick screen with internal resistance and open circuit voltage
- Capacity grading test (the final verdict)
- Request the original factory quality inspection report
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Compiled by Novel Home Goods (Yiwu foreign trade and one-stop sourcing services) for overseas buyers sourcing in China. We provide sourcing, inspection and local support in Yiwu.