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        "lede": "How cells fail dangerously, how that is tested, and what is built in to stop it.",
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          "title": "Different conduction paths",
          "text": "A separator prevents direct electronic contact while permitting ionic transport through its electrolyte-filled structure."
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        "mentions": []
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        "name": "Ceramic-coated separator",
        "section": "topic-electrolytes",
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      "id": "term:onset-temperature",
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      "label": "Onset temperature",
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        "definition": "The temperature at which a cell begins to generate heat by itself, as the SEI starts to decompose, typically 80–120 °C. Measured in an accelerating rate calorimeter, it marks the start of the path to thermal runaway, not the runaway itself.",
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        "definition": "The two commodity polyolefins of a cell. Almost every separator is PE, PP or a layered combination: PE melts near 130 °C and closes its pores, while PP keeps its shape to about 165 °C. PP also forms the heat-sealing inner layer of pouch foil, and both appear in packs as insulating films and moulded parts.",
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        "mentions": []
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      "id": "lesson:fundamentals/cell-architecture/",
      "type": "Lesson",
      "label": "Lesson 1B · Cell architecture",
      "properties": {
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}