Battery knowledge · Modules, packs and battery management
Secondary protection
A second, independent protection layer in a lithium-ion pack that acts if the primary protection circuit fails. A separate chip watches each cell’s voltage and, on overcharge, drives a heater inside a three-terminal fuse so that it blows for good; the same fuse also opens on overcurrent. Laptop and power-tool packs routinely carry one.
- Also called
- secondary protection IC, self-control protector, three-terminal fuse, overvoltage protector, chemical fuse
Example
Modules, packs and battery management: an example situation
Twelve 3.6 V, 5 Ah cells in 6s2p give 21.6 V, 10 Ah and 216 Wh nominally before other restrictions.
Read Secondary protection alongside Fuse in this context. A link that melts and opens the circuit when current exceeds its rating. Packs use a main fuse in the high-voltage path and often a small fuse on each parallel cell connection, so one shorted cell does not drain its neighbours into the fault.
Use in Lemonergy
Make series/parallel architecture explicit.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Extended Kalman filtering for battery management systems of LiPB-based HEV battery packs: Part 2. Modeling and identification
Gregory L. Plett · Journal of Power Sources · 2004
Topic background · Battery charge balance, open-circuit voltage, ohmic loss, polarization dynamics and model identification; parameters require cell-specific data.
- Getting Started with the BQ76925
Texas Instruments · 2019
Topic background · A concrete BMS analog front-end example: cell voltage, current, temperature measurement and MCU integration.