Functional and technical safety concepts

Example

Use in Lemonergy

Relate protection to faults, detection and response.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Connected concepts

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Functional safety

The discipline, standardised for vehicles in ISO 26262, of making sure electronic failures do not cause harm. Battery functions such as overvoltage protection are classified by risk into ASIL levels A to D, which set how redundant and verified their hardware and software must be.

Hazard analysis and risk assessment

The ISO 26262 step that lists the hazards a function could cause, rates each in its driving situation for severity (S0–S3), exposure (E0–E4) and controllability (C0–C3), and combines them into an ASIL or QM. Each hazard becomes a safety goal, such as ‘prevent cell overcharge leading to thermal runaway’, that the design must meet.

Hardware safety metrics

The ISO 26262 numbers showing that random hardware failures are under control. The single-point and latent fault metrics are the shares of failures that safety mechanisms cover — at least 99% and 90% for ASIL D — and PMHF is the residual rate of violating a safety goal, below 10⁻⁸ per hour (10 FIT) for ASIL D.

Redundant BMS architecture

A BMS design that duplicates safety-critical functions so no single failure can hide a hazard: an independent second voltage monitor beside the main measurement chip, two current sensors of different principle, a watchdog or second processor, and two separate paths to open the contactors. It is how BMS hardware reaches ASIL C or D.

Safety case

A structured argument, backed by evidence, that a system is acceptably safe for its intended use: hazard analysis, safety requirements, design analyses such as FMEA, and test and review results, all traced to one another. ISO 26262 requires one for every item with an ASIL, and a functional safety assessment reviews it before release.

References & further reading

Technical references

1. ISO 26262-1:2018 — Road vehicles — Functional safety — Part 1: Vocabulary

   International Organization for Standardization · 2018

   Technical reference · Scope and terminology of automotive electrical/electronic functional safety. The catalogue is not the full standard.