{
  "node": {
    "id": "term:safety-concept",
    "type": "Term",
    "label": "Functional and technical safety concepts",
    "properties": {
      "id": "safety-concept",
      "name": "Functional and technical safety concepts",
      "abbr": "FSC, TSC",
      "aka": [
        "functional safety concept",
        "technical safety concept"
      ],
      "section": "topic-hvsafety",
      "definition": "The two layers that turn safety goals into a design under ISO 26262. The functional safety concept states what must happen — detect a cell above its voltage limit and open the contactors within a set time — without naming parts; the technical safety concept allocates those requirements to hardware and software, such as a specific monitoring chip, diagnostic and contactor driver.",
      "related": [
        "hara",
        "functional-safety",
        "hardware-safety-metrics",
        "safety-case",
        "redundant-bms"
      ],
      "url": "https://lemonergy.com/learn/glossary/safety-concept/",
      "mentions": [
        "contactor"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:5142",
      "source": "term:safety-concept",
      "target": "topic:topic-hvsafety",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:5143",
      "source": "term:safety-concept",
      "target": "term:hara",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5144",
      "source": "term:safety-concept",
      "target": "term:functional-safety",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5145",
      "source": "term:safety-concept",
      "target": "term:hardware-safety-metrics",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5146",
      "source": "term:safety-concept",
      "target": "term:safety-case",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:5147",
      "source": "term:safety-concept",
      "target": "term:redundant-bms",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/safety-concept/contactor",
      "source": "term:safety-concept",
      "target": "term:contactor",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:5149",
      "source": "term:safety-concept",
      "target": "reference:iso-functional",
      "type": "cites",
      "properties": {
        "sourceFile": "wiki-references.json",
        "scope": "direct technical reference"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-hvsafety",
      "type": "Topic",
      "label": "High-voltage and functional safety",
      "properties": {
        "id": "topic-hvsafety",
        "name": "High-voltage and functional safety",
        "lede": "Keeping people safe from the pack’s voltage and keeping its electronics safe when they fail: insulation, switching, fusing and the functional-safety process.",
        "context": "Relate protection to faults, detection and response.",
        "example": "Normal-operation current limits do not demonstrate correct contactor behavior under a welded-contact or sensor fault.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-basics/",
        "lesson_label": "Open battery basics"
      }
    },
    {
      "id": "term:hara",
      "type": "Term",
      "label": "Hazard analysis and risk assessment",
      "properties": {
        "id": "hara",
        "name": "Hazard analysis and risk assessment",
        "abbr": "HARA",
        "section": "topic-hvsafety",
        "definition": "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.",
        "related": [
          "functional-safety",
          "safety-concept",
          "fmea",
          "safety-case",
          "thermal-runaway"
        ],
        "url": "https://lemonergy.com/learn/glossary/hara/",
        "mentions": [
          "overcharge"
        ]
      }
    },
    {
      "id": "term:functional-safety",
      "type": "Term",
      "label": "Functional safety",
      "properties": {
        "id": "functional-safety",
        "name": "Functional safety",
        "abbr": "ISO 26262",
        "aka": [
          "ASIL"
        ],
        "section": "topic-hvsafety",
        "definition": "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.",
        "related": [
          "bms",
          "high-voltage-interlock",
          "insulation-resistance",
          "fmea",
          "mcu",
          "iso-13849"
        ],
        "url": "https://lemonergy.com/learn/glossary/functional-safety/",
        "mentions": []
      }
    },
    {
      "id": "term:hardware-safety-metrics",
      "type": "Term",
      "label": "Hardware safety metrics",
      "properties": {
        "id": "hardware-safety-metrics",
        "name": "Hardware safety metrics",
        "abbr": "SPFM, LFM, PMHF",
        "aka": [
          "single-point fault metric",
          "latent fault metric",
          "probabilistic metric for random hardware failures",
          "hardware architectural metrics"
        ],
        "section": "topic-hvsafety",
        "definition": "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.",
        "related": [
          "functional-safety",
          "diagnostic-coverage",
          "safety-concept",
          "fmea",
          "redundant-bms"
        ],
        "url": "https://lemonergy.com/learn/glossary/hardware-safety-metrics/",
        "mentions": []
      }
    },
    {
      "id": "term:safety-case",
      "type": "Term",
      "label": "Safety case",
      "properties": {
        "id": "safety-case",
        "name": "Safety case",
        "aka": [
          "safety argument"
        ],
        "section": "topic-hvsafety",
        "definition": "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.",
        "related": [
          "functional-safety",
          "hara",
          "safety-concept",
          "fmea",
          "hardware-safety-metrics"
        ],
        "url": "https://lemonergy.com/learn/glossary/safety-case/",
        "mentions": []
      }
    },
    {
      "id": "term:redundant-bms",
      "type": "Term",
      "label": "Redundant BMS architecture",
      "properties": {
        "id": "redundant-bms",
        "name": "Redundant BMS architecture",
        "aka": [
          "redundant BMS",
          "secondary safety monitor"
        ],
        "section": "topic-pack",
        "definition": "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.",
        "related": [
          "functional-safety",
          "bms-architecture",
          "hardware-safety-metrics",
          "lockstep-core",
          "current-sensor",
          "diagnostic-coverage"
        ],
        "url": "https://lemonergy.com/learn/glossary/redundant-bms/",
        "mentions": [
          "bms"
        ]
      }
    },
    {
      "id": "term:contactor",
      "type": "Term",
      "label": "Contactor",
      "properties": {
        "id": "contactor",
        "name": "Contactor",
        "section": "topic-hvsafety",
        "definition": "A heavy-duty electrically operated switch that connects the pack to the vehicle or inverter and opens it on fault or shutdown. Packs use at least two, one per pole, plus a pre-charge path to avoid welding them on the first connection.",
        "related": [
          "pre-charge",
          "battery-disconnect-unit",
          "pyrofuse",
          "bms"
        ],
        "url": "https://lemonergy.com/learn/glossary/contactor/",
        "mentions": [
          "inverter"
        ]
      }
    },
    {
      "id": "reference:iso-functional",
      "type": "Reference",
      "label": "ISO 26262-1:2018 — Road vehicles — Functional safety — Part 1: Vocabulary",
      "properties": {
        "title": "ISO 26262-1:2018 — Road vehicles — Functional safety — Part 1: Vocabulary",
        "publisher": "International Organization for Standardization",
        "url": "https://www.iso.org/standard/68383.html",
        "type": "Standard catalogue",
        "scope": "Scope and terminology of automotive electrical/electronic functional safety. The catalogue is not the full standard.",
        "year": 2018,
        "accessed": "2026-10-27"
      }
    }
  ]
}