Inspect against an approved baseline
A receiving inspection is useful only when it checks a defined product. Keep the approved specification, drawing, label artwork, connector information and revision history together. State the supplier's model identifier and any customer part number. Decide which characteristics are critical to the equipment and how each will be verified. An inspection plan should be appropriate to the project and carried out by trained personnel. It should never rely on opening a sealed pack or improvising hazardous electrical tests during routine receiving.
Check identification before measurements
Confirm the shipping documents, labels and lot information match the purchase order. Inspect the packaging for damage and check for visible deformation, damaged cables or other abnormal conditions before handling or testing the pack. Use the agreed process for isolating and reporting suspect goods. Record photographs and lot identifiers so the supplier can investigate a specific shipment. Avoid treating an unmarked unit as equivalent merely because its color and general shape resemble the approved sample.
Verify interfaces and mechanical features
Check the agreed overall dimensions, mounting details, connector type, cable length, polarity markings and relevant tolerances. Use an appropriate fixture or drawing-based method rather than relying on visual comparison alone. Ensure that inspection covers the features that affect assembly, including cable exits and access to mounting points. A small change in connector keying or orientation can stop production even when the electrical ratings remain correct. Capture deviations before the packs reach the assembly line.
Use controlled electrical acceptance checks
Select electrical checks with the supplier and qualified engineering team. An agreed open-circuit voltage window may be one receiving criterion, but it does not prove capacity or complete health. Where capacity sampling is required, define the charging procedure, rest time, load, temperature and discharge endpoint. Retain results with the tested unit identification and instrument information. Do not compare measurements from different methods as though they were interchangeable. Escalate abnormal readings through the agreed quality process rather than experimenting with recovery.
Close the loop on changes and trends
Track repeated deviations by lot and characteristic so that quality discussions use evidence. Ask the supplier to explain substitutions or revisions before accepting them into the approved configuration. A change in cell model, protection hardware, firmware or construction can require engineering review even when the commercial model name stays the same. Periodically compare incoming results with the approved sample and specification. This approach supports consistent OEM procurement without assuming that a single initial sample guarantees every future shipment will behave identically. Retain the disposition of rejected or conditionally accepted lots so later investigations can reconstruct what happened without relying on memory.
Sources & further reading
Prepared for the 18650 battery packs collection. General engineering guidance does not replace a model-specific datasheet or application validation. Source review: 4 November 2026.