{
  "node": {
    "id": "term:thermal-runaway-energy",
    "type": "Term",
    "label": "Thermal-runaway energy",
    "properties": {
      "id": "thermal-runaway-energy",
      "name": "Thermal-runaway energy",
      "aka": [
        "heat release in thermal runaway",
        "total heat release"
      ],
      "section": "topic-safety",
      "definition": "The heat a cell releases when it fails, which exceeds its stored electrical energy because decomposition reactions add heat of their own. Calorimetry on 18650 cells has measured decomposition energy up to about twice the electrical energy, and combustion of the vented contents up to about six times, so a battery fire carries far more energy than its kWh rating.",
      "related": [
        "thermal-runaway",
        "accelerating-rate-calorimetry",
        "off-gas",
        "flammability",
        "nominal-energy",
        "fire-suppression"
      ],
      "url": "https://lemonergy.com/learn/glossary/thermal-runaway-energy/",
      "mentions": [
        "kilowatt-hour",
        "cylindrical-cell"
      ]
    }
  },
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      "id": "edge:6643",
      "source": "term:thermal-runaway-energy",
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    {
      "id": "edge:6644",
      "source": "term:thermal-runaway-energy",
      "target": "term:nominal-energy",
      "type": "relatedTo",
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      "id": "edge:6645",
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        "meaning": "Related context; not a causal claim"
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      "id": "edge:mentions/thermal-runaway-energy/kilowatt-hour",
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    {
      "id": "topic:topic-safety",
      "type": "Topic",
      "label": "Safety and abuse",
      "properties": {
        "id": "topic-safety",
        "name": "Safety and abuse",
        "lede": "How cells fail dangerously, how that is tested, and what is built in to stop it.",
        "context": "Connect mechanisms with appropriate test evidence.",
        "example": "A low normal-load temperature does not demonstrate thermal-runaway containment.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/battery-aging/",
        "lesson_label": "Open degradation mechanisms"
      }
    },
    {
      "id": "term:thermal-runaway",
      "type": "Term",
      "label": "Thermal runaway",
      "properties": {
        "id": "thermal-runaway",
        "name": "Thermal runaway",
        "section": "topic-safety",
        "definition": "Self-accelerating heating in a cell: heat speeds up reactions that release more heat, until the cell vents, catches fire or ruptures. An internal short, overcharge or external heating can trigger it.",
        "related": [
          "onset-temperature",
          "thermal-propagation",
          "venting",
          "separator-shutdown",
          "thermal-runaway-energy",
          "exothermic"
        ],
        "lesson": "fundamentals/cell-anatomy/#short-circuit",
        "url": "https://lemonergy.com/learn/glossary/thermal-runaway/",
        "mentions": [
          "overcharge"
        ]
      }
    },
    {
      "id": "term:accelerating-rate-calorimetry",
      "type": "Term",
      "label": "Accelerating rate calorimetry",
      "properties": {
        "id": "accelerating-rate-calorimetry",
        "name": "Accelerating rate calorimetry",
        "abbr": "ARC",
        "section": "topic-safety",
        "definition": "A test in which a cell sits in an adiabatic chamber that follows its temperature, so any self-heating is not lost to the surroundings. It measures the onset temperature, the self-heating rate and the temperature at which runaway becomes unstoppable.",
        "related": [
          "onset-temperature",
          "thermal-runaway",
          "differential-scanning-calorimetry"
        ],
        "url": "https://lemonergy.com/learn/glossary/accelerating-rate-calorimetry/",
        "mentions": [
          "adiabatic-isothermal"
        ]
      }
    },
    {
      "id": "term:off-gas",
      "type": "Term",
      "label": "Off-gas",
      "properties": {
        "id": "off-gas",
        "name": "Off-gas",
        "aka": [
          "vent gas"
        ],
        "section": "topic-safety",
        "definition": "The mixture released when a cell vents: electrolyte vapour, hydrogen, carbon monoxide, carbon dioxide and hydrocarbons, with hydrogen fluoride. It is flammable and toxic, and gas sensors detect it before smoke or heat in a storage container.",
        "related": [
          "venting",
          "hydrofluoric-acid",
          "gas-detection",
          "thermal-runaway"
        ],
        "url": "https://lemonergy.com/learn/glossary/off-gas/",
        "mentions": [
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:flammability",
      "type": "Term",
      "label": "Flammability",
      "properties": {
        "id": "flammability",
        "name": "Flammability",
        "section": "topic-safety",
        "definition": "The property that makes lithium-ion fires hard to fight: the carbonate solvents have flash points near room temperature, and the positive electrode releases its own oxygen when hot, so the fire does not need air. Solid and non-flammable electrolytes aim to remove this.",
        "related": [
          "carbonate-solvent",
          "thermal-runaway",
          "solid-state-battery",
          "fire-suppression"
        ],
        "url": "https://lemonergy.com/learn/glossary/flammability/",
        "mentions": [
          "electrode",
          "positive-electrode"
        ]
      }
    },
    {
      "id": "term:nominal-energy",
      "type": "Term",
      "label": "Nominal energy",
      "properties": {
        "id": "nominal-energy",
        "name": "Nominal energy",
        "section": "topic-ratings",
        "definition": "Nominal capacity times nominal voltage, in watt-hours: the headline energy figure on a datasheet. The energy actually delivered depends on the load, the temperature and how the voltage curve is weighted.",
        "formula": "E = Q × V_nominal",
        "unit": "Wh",
        "related": [
          "nominal-capacity",
          "nominal-voltage",
          "watt-hour",
          "energy-density"
        ],
        "lesson": "fundamentals/capacity-and-c-rate/#energy",
        "example": {
          "title": "Turn capacity into a nominal energy",
          "text": "A 5 Ah cell with a nominal voltage of 3.6 V has 18 Wh of nominal energy. This estimate uses the nominal voltage; delivered energy is the integral of measured terminal voltage multiplied by current."
        },
        "url": "https://lemonergy.com/learn/glossary/nominal-energy/",
        "mentions": [
          "datasheet",
          "discharge-curve"
        ]
      }
    },
    {
      "id": "term:fire-suppression",
      "type": "Term",
      "label": "Fire suppression",
      "properties": {
        "id": "fire-suppression",
        "name": "Fire suppression",
        "section": "topic-safety",
        "definition": "Systems that cool or smother a battery fire: water mist and flooding for cooling, inert gas or aerosol for enclosed storage containers. Because the cell makes its own oxygen, suppression mainly limits spread and cools neighbours rather than extinguishing the failing cell.",
        "related": [
          "flammability",
          "thermal-propagation",
          "gas-detection",
          "stationary-storage",
          "firefighter-access"
        ],
        "url": "https://lemonergy.com/learn/glossary/fire-suppression/",
        "mentions": []
      }
    },
    {
      "id": "term:kilowatt-hour",
      "type": "Term",
      "label": "Kilowatt-hour",
      "properties": {
        "id": "kilowatt-hour",
        "name": "Kilowatt-hour",
        "abbr": "kWh",
        "section": "topic-units",
        "definition": "One thousand watt-hours, the unit for pack and system energy. An electric car carries 40–100 kWh; grid storage is quoted in megawatt-hours (1000 kWh) and factory output in gigawatt-hours per year.",
        "unit": "kWh",
        "related": [
          "watt-hour",
          "nominal-energy",
          "cost-per-kwh",
          "gigafactory"
        ],
        "url": "https://lemonergy.com/learn/glossary/kilowatt-hour/",
        "mentions": []
      }
    },
    {
      "id": "term:cylindrical-cell",
      "type": "Term",
      "label": "Cylindrical cell",
      "properties": {
        "id": "cylindrical-cell",
        "name": "Cylindrical cell",
        "aka": [
          "18650",
          "21700",
          "4680"
        ],
        "section": "topic-chemistries",
        "definition": "A cell made by winding the electrodes into a jelly roll and sealing it in a round metal can. Sizes are named by their dimensions: a 21700 cell is 21 mm across and 70 mm long.",
        "related": [
          "jelly-roll",
          "can",
          "tabless-design",
          "prismatic-cell",
          "pouch-cell",
          "centre-pin"
        ],
        "lesson": "fundamentals/cell-production/#formats",
        "example": {
          "title": "Shape versus ratings",
          "text": "A cylindrical shape does not supply the model’s capacity, resistance or voltage limits; those belong to the actual cell."
        },
        "url": "https://lemonergy.com/learn/glossary/cylindrical-cell/",
        "mentions": [
          "winding"
        ]
      }
    },
    {
      "id": "reference:feng-runaway",
      "type": "Reference",
      "label": "Thermal runaway mechanism of lithium ion battery for electric vehicles: A review",
      "properties": {
        "title": "Thermal runaway mechanism of lithium ion battery for electric vehicles: A review",
        "publisher": "Energy Storage Materials",
        "url": "https://doi.org/10.1016/j.ensm.2017.05.013",
        "type": "Review article",
        "scope": "Electrical, mechanical and thermal abuse; thermal-runaway mechanisms and propagation.",
        "year": 2018,
        "authors": [
          "Xuning Feng et al."
        ],
        "accessed": "2026-10-27"
      }
    }
  ]
}