{
  "node": {
    "id": "term:exothermic",
    "type": "Term",
    "label": "Exothermic and endothermic",
    "properties": {
      "id": "exothermic",
      "name": "Exothermic and endothermic",
      "section": "topic-safety",
      "definition": "A reaction that releases heat is exothermic; one that absorbs it is endothermic. Thermal runaway is a chain of exothermic reactions; a few cell processes, such as graphite lithiation at some stages, are mildly endothermic and cool the cell.",
      "related": [
        "thermal-runaway",
        "heat-generation",
        "entropy-coefficient"
      ],
      "url": "https://lemonergy.com/learn/glossary/exothermic/",
      "mentions": [
        "graphite",
        "calcination"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:3658",
      "source": "term:exothermic",
      "target": "topic:topic-safety",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:3659",
      "source": "term:exothermic",
      "target": "term:thermal-runaway",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:3660",
      "source": "term:exothermic",
      "target": "term:heat-generation",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:3661",
      "source": "term:exothermic",
      "target": "term:entropy-coefficient",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/exothermic/graphite",
      "source": "term:exothermic",
      "target": "term:graphite",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/exothermic/calcination",
      "source": "term:exothermic",
      "target": "term:calcination",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "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:heat-generation",
      "type": "Term",
      "label": "Heat generation",
      "properties": {
        "id": "heat-generation",
        "name": "Heat generation",
        "aka": [
          "Bernardi equation"
        ],
        "section": "topic-thermal",
        "definition": "The heat a cell produces in operation: an irreversible part equal to current times overpotential, and a reversible part from the entropy change, I·T·dE/dT. The Bernardi equation sums them and feeds every thermal model.",
        "formula": "q = I(V − E_OCV) + I·T·(dE/dT)",
        "unit": "W",
        "related": [
          "entropy-coefficient",
          "internal-resistance",
          "thermal-model",
          "thermal-management",
          "exothermic"
        ],
        "example": {
          "title": "Keep reversible and irreversible heat separate",
          "text": "With charging current +5 A and terminal voltage 0.10 V above OCV, the irreversible term is 0.50 W. At 300 K with dE/dT = +0.1 mV/K, the reversible contribution is +0.15 W, giving 0.65 W under this sign convention."
        },
        "url": "https://lemonergy.com/learn/glossary/heat-generation/",
        "mentions": [
          "overpotential"
        ]
      }
    },
    {
      "id": "term:entropy-coefficient",
      "type": "Term",
      "label": "Entropy coefficient",
      "properties": {
        "id": "entropy-coefficient",
        "name": "Entropy coefficient",
        "section": "topic-electrochemistry",
        "definition": "The change of open-circuit voltage with temperature, dE/dT, usually a fraction of a millivolt per kelvin and varying with state of charge. It sets the reversible heat a cell absorbs or releases, which can be a large share of total heat at low current.",
        "formula": "q_rev = I·T·(dE/dT)",
        "unit": "mV/K",
        "related": [
          "heat-generation",
          "gibbs-free-energy",
          "open-circuit-voltage"
        ],
        "example": {
          "title": "Track reversible heat with the sign convention",
          "text": "With positive charging current of 5 A, temperature 300 K and dE/dT = 0.1 mV/K, q_rev = IT(dE/dT) gives +0.15 W. Reversing the current reverses this contribution."
        },
        "notes": [
          "The glossary plot takes positive heat as heat released. Other sources may use positive-discharge current and a different written sign."
        ],
        "url": "https://lemonergy.com/learn/glossary/entropy-coefficient/",
        "mentions": [
          "state-of-charge"
        ]
      }
    },
    {
      "id": "term:graphite",
      "type": "Term",
      "label": "Graphite",
      "properties": {
        "id": "graphite",
        "name": "Graphite",
        "section": "topic-components",
        "definition": "Layered carbon, the negative active material of nearly all lithium-ion cells. Lithium intercalates between its layers up to LiC₆, a theoretical 372 mAh/g, at a potential about 0.1 V above lithium metal.",
        "related": [
          "anode-active-material",
          "intercalation",
          "natural-graphite",
          "synthetic-graphite",
          "lithium-plating"
        ],
        "lesson": "fundamentals/cell-anatomy/#components",
        "example": {
          "title": "Compare matching mass bases",
          "text": "A graphite value per gram of active material cannot be directly compared with a value including binder, additive and foil."
        },
        "url": "https://lemonergy.com/learn/glossary/graphite/",
        "mentions": [
          "milliampere-hour",
          "active-material"
        ]
      }
    },
    {
      "id": "term:calcination",
      "type": "Term",
      "label": "Calcination",
      "properties": {
        "id": "calcination",
        "name": "Calcination",
        "aka": [
          "lithiation",
          "sintering of CAM"
        ],
        "section": "topic-manufacturing",
        "definition": "Firing the precursor with a lithium source — lithium carbonate or, for high-nickel materials, lithium hydroxide — at 700–900 °C in kilns to form the layered oxide. Atmosphere and temperature profile control the crystal quality.",
        "related": [
          "precursor",
          "cathode-active-material",
          "lithium-hydroxide",
          "lithium-carbonate"
        ],
        "url": "https://lemonergy.com/learn/glossary/calcination/",
        "mentions": [
          "layered-oxide"
        ]
      }
    }
  ]
}