{
  "node": {
    "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"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:815",
      "source": "term:cylindrical-cell",
      "target": "topic:topic-chemistries",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:816",
      "source": "term:cylindrical-cell",
      "target": "term:jelly-roll",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:817",
      "source": "term:cylindrical-cell",
      "target": "term:can",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:818",
      "source": "term:cylindrical-cell",
      "target": "term:tabless-design",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:819",
      "source": "term:cylindrical-cell",
      "target": "term:prismatic-cell",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:820",
      "source": "term:cylindrical-cell",
      "target": "term:pouch-cell",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:821",
      "source": "term:cylindrical-cell",
      "target": "term:centre-pin",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/cylindrical-cell/winding",
      "source": "term:cylindrical-cell",
      "target": "term:winding",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    },
    {
      "id": "edge:823",
      "source": "term:cylindrical-cell",
      "target": "lesson:fundamentals/cell-production/",
      "type": "explainedIn",
      "properties": {
        "sourceFile": "terms.json",
        "url": "https://lemonergy.com/learn/fundamentals/cell-production/#formats"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-chemistries",
      "type": "Topic",
      "label": "Lithium-ion chemistries and cell formats",
      "properties": {
        "id": "topic-chemistries",
        "name": "Lithium-ion chemistries and cell formats",
        "lede": "The electrode materials that define a lithium-ion cell, the crystal structures behind them, and the shapes cells are built in.",
        "context": "Separate chemistry from form factor.",
        "example": "Two cylindrical cells can share dimensions yet differ in cathode, capacity and current limits.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-architecture/",
        "lesson_label": "Open cell architecture"
      }
    },
    {
      "id": "term:jelly-roll",
      "type": "Term",
      "label": "Jelly roll",
      "properties": {
        "id": "jelly-roll",
        "name": "Jelly roll",
        "section": "topic-components",
        "definition": "Electrodes and separators wound together into a spiral. It is the inside of a cylindrical cell and of many prismatic cells; large pouch cells usually use stacked sheets instead.",
        "related": [
          "winding",
          "cylindrical-cell",
          "prismatic-cell",
          "stacking"
        ],
        "lesson": "fundamentals/cell-architecture/#whole-cell",
        "example": {
          "title": "Unroll the geometry",
          "text": "A wound assembly contains long electrode and separator strips; the cylindrical exterior does not make its electrodes solid cylinders."
        },
        "url": "https://lemonergy.com/learn/glossary/jelly-roll/",
        "mentions": []
      }
    },
    {
      "id": "term:can",
      "type": "Term",
      "label": "Can",
      "properties": {
        "id": "can",
        "name": "Can",
        "aka": [
          "casing",
          "housing"
        ],
        "section": "topic-components",
        "definition": "The rigid metal case of a cylindrical or prismatic cell, usually nickel-plated steel or aluminium. It holds the stack under pressure, contains the electrolyte and, in a cylindrical cell, doubles as the negative terminal.",
        "related": [
          "cylindrical-cell",
          "prismatic-cell",
          "pouch-foil",
          "vent",
          "helium-leak-test"
        ],
        "url": "https://lemonergy.com/learn/glossary/can/",
        "mentions": [
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:tabless-design",
      "type": "Term",
      "label": "Tabless design",
      "properties": {
        "id": "tabless-design",
        "name": "Tabless design",
        "aka": [
          "full-tab",
          "shingled tab"
        ],
        "section": "topic-chemistries",
        "definition": "A cylindrical-cell construction in which the whole uncoated edge of each foil is folded and welded to the end cap instead of one or two narrow tabs. The current path shortens from metres to millimetres, cutting resistance and heating in large-format cells.",
        "related": [
          "tab",
          "cylindrical-cell",
          "internal-resistance",
          "tab-welding"
        ],
        "url": "https://lemonergy.com/learn/glossary/tabless-design/",
        "mentions": []
      }
    },
    {
      "id": "term:prismatic-cell",
      "type": "Term",
      "label": "Prismatic cell",
      "properties": {
        "id": "prismatic-cell",
        "name": "Prismatic cell",
        "section": "topic-chemistries",
        "definition": "A cell in a rigid rectangular metal case, holding either a flattened jelly roll or stacked sheets. Large prismatic cells pack tightly into battery packs.",
        "related": [
          "can",
          "jelly-roll",
          "stacking",
          "cylindrical-cell",
          "pouch-cell"
        ],
        "lesson": "fundamentals/cell-production/#formats",
        "example": {
          "title": "Geometry is one constraint",
          "text": "Two rectangular cells can fit similar spaces but use different terminals and electrical ratings."
        },
        "url": "https://lemonergy.com/learn/glossary/prismatic-cell/",
        "mentions": []
      }
    },
    {
      "id": "term:pouch-cell",
      "type": "Term",
      "label": "Pouch cell",
      "properties": {
        "id": "pouch-cell",
        "name": "Pouch cell",
        "aka": [
          "lithium polymer cell",
          "LiPo"
        ],
        "section": "topic-chemistries",
        "definition": "A cell sealed in a flexible bag of aluminium laminated with plastic, holding stacked electrode sheets in larger cells or a flattened wound roll in many small ones. It is light and easy to cool, but needs outside support and can visibly swell if gas forms inside.",
        "related": [
          "pouch-foil",
          "stacking",
          "swelling",
          "degassing",
          "prismatic-cell"
        ],
        "lesson": "fundamentals/cell-production/#formats",
        "example": {
          "title": "Include mechanical support",
          "text": "A pouch encloses layered electrodes. Support provided by the module is part of the complete design, separate from the active layers."
        },
        "url": "https://lemonergy.com/learn/glossary/pouch-cell/",
        "mentions": [
          "electrode"
        ]
      }
    },
    {
      "id": "term:centre-pin",
      "type": "Term",
      "label": "Centre pin",
      "properties": {
        "id": "centre-pin",
        "name": "Centre pin",
        "aka": [
          "center pin",
          "core pin"
        ],
        "section": "topic-components",
        "definition": "A hollow metal tube placed in the core of a cylindrical cell’s jelly roll, in the hole left by the winding mandrel. It stops the winding collapsing inward and keeps a clear channel for gas to reach the vent during failure; X-ray studies of 18650 cells in thermal runaway showed unsupported cores collapsing after venting.",
        "related": [
          "cylindrical-cell",
          "jelly-roll",
          "vent",
          "thermal-runaway",
          "winding",
          "internal-short-circuit"
        ],
        "url": "https://lemonergy.com/learn/glossary/centre-pin/",
        "mentions": []
      }
    },
    {
      "id": "term:winding",
      "type": "Term",
      "label": "Winding",
      "properties": {
        "id": "winding",
        "name": "Winding",
        "section": "topic-manufacturing",
        "definition": "Rolling the two electrode strips and two separator strips together around a mandrel into a jelly roll. It is fast and well understood, and it produces the round roll of a cylindrical cell or the flattened roll of many prismatic cells.",
        "related": [
          "jelly-roll",
          "stacking",
          "cylindrical-cell",
          "prismatic-cell"
        ],
        "lesson": "fundamentals/cell-production/#assembly",
        "url": "https://lemonergy.com/learn/glossary/winding/",
        "mentions": [
          "electrode",
          "separator"
        ]
      }
    },
    {
      "id": "lesson:fundamentals/cell-production/",
      "type": "Lesson",
      "label": "Lesson 3 · Cell production",
      "properties": {
        "url": "https://lemonergy.com/learn/fundamentals/cell-production/"
      }
    }
  ]
}