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IEC 60285: Alkaline Secondary Batteries — Why NiCd Remains Irreplaceable at Temperature Extremes
Li-Ion Has the Highest Energy Density, Lead-Acid Is Cheapest — But Only NiCd Still Works at -40°C
IEC 60285:1999 specifies alkaline secondary battery (NiCd and NiMH) requirements. In substation DC supplies, railway signaling, and emergency lighting, NiCd remains dominant due to extreme temperature range (-40 to +60 °C) and 20–25 year life — despite one-third the energy density of Li-ion.
| Battery | -20°C Capacity | -40°C Capacity | Cycle Life | Typical Application |
|---|---|---|---|---|
| NiCd | >80% | >50% | 2,000–4,000 | Substation DC, railway, emergency lighting |
| VRLA | 20–30% | <10% | 300–500 | UPS, telecom |
| Li-ion | 30–50%(but charging at -20°C is dangerous) | Cannot charge | 500–2,000 | Consumer electronics, EVs |
The Li-ion low-temperature charging prohibition: Below 0 °C, charging Li-ion causes lithium metal to plate on the anode surface as dendrites — dendrites penetrate the separator causing internal short-circuits, potentially triggering thermal runaway. This is a fundamental physicochemical limitation. NiCd has no such issue — it can be safely charged at -40 °C, only with reduced charge acceptance. Arctic substation DC systems are almost exclusively NiCd.
TN Lab — Li-ion has the highest energy density. Lead-acid is cheapest. But at temperature extremes, NiCd remains irreplaceable.
