{
  "node": {
    "id": "term:cell-packing-arrangement",
    "type": "Term",
    "label": "Cell packing arrangement",
    "properties": {
      "id": "cell-packing-arrangement",
      "name": "Cell packing arrangement",
      "aka": [
        "hexagonal packing",
        "nested layout",
        "staggered layout",
        "square packing",
        "cubic layout"
      ],
      "section": "topic-pack",
      "definition": "How round cells sit side by side. Square packing, in rows and columns, fills π/4 ≈ 78.5 % of the footprint and leaves straight channels for cooling; hexagonal or nested packing, each row shifted by half a cell, fills π/(2√3) ≈ 90.7 % and needs about 13 % less area for the same cells.",
      "related": [
        "cylindrical-cell",
        "cell-holder",
        "cell-to-pack-ratio",
        "thermal-management",
        "series-parallel"
      ],
      "url": "https://lemonergy.com/learn/glossary/cell-packing-arrangement/",
      "mentions": []
    }
  },
  "edges": [
    {
      "id": "edge:belongsTo/term:cell-packing-arrangement/topic:topic-pack",
      "source": "term:cell-packing-arrangement",
      "target": "topic:topic-pack",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:relatedTo/term:cell-packing-arrangement/term:cylindrical-cell",
      "source": "term:cell-packing-arrangement",
      "target": "term:cylindrical-cell",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:cell-packing-arrangement/term:cell-holder",
      "source": "term:cell-packing-arrangement",
      "target": "term:cell-holder",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:cell-packing-arrangement/term:cell-to-pack-ratio",
      "source": "term:cell-packing-arrangement",
      "target": "term:cell-to-pack-ratio",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:cell-packing-arrangement/term:thermal-management",
      "source": "term:cell-packing-arrangement",
      "target": "term:thermal-management",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:relatedTo/term:cell-packing-arrangement/term:series-parallel",
      "source": "term:cell-packing-arrangement",
      "target": "term:series-parallel",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "id": "topic:topic-pack",
      "type": "Topic",
      "label": "Modules, packs and battery management",
      "properties": {
        "id": "topic-pack",
        "name": "Modules, packs and battery management",
        "lede": "From a single cell to a working battery system, and the electronics that keep it safe.",
        "context": "Make series/parallel architecture explicit.",
        "example": "Twelve 3.6 V, 5 Ah cells in 6s2p give 21.6 V, 10 Ah and 216 Wh nominally before other restrictions.",
        "lesson_url": "https://lemonergy.com/learn/fundamentals/cell-architecture/",
        "lesson_label": "Open cell architecture"
      }
    },
    {
      "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": "term:cell-holder",
      "type": "Term",
      "label": "Cell holder",
      "properties": {
        "id": "cell-holder",
        "name": "Cell holder",
        "aka": [
          "cell bracket",
          "cell carrier",
          "cell spacer",
          "cell frame"
        ],
        "section": "topic-pack",
        "definition": "A moulded plastic frame with a socket for each cylindrical cell, which fixes the spacing, stops cells rubbing through their wrappers under vibration and leaves gaps for air or potting. A few millimetres between cells also slows thermal propagation; many automotive modules use the same idea at larger scale.",
        "related": [
          "cylindrical-cell",
          "cell-packing-arrangement",
          "thermal-propagation",
          "potting-compound"
        ],
        "url": "https://lemonergy.com/learn/glossary/cell-holder/",
        "mentions": []
      }
    },
    {
      "id": "term:cell-to-pack-ratio",
      "type": "Term",
      "label": "Cell-to-pack ratio",
      "properties": {
        "id": "cell-to-pack-ratio",
        "name": "Cell-to-pack ratio",
        "aka": [
          "gravimetric cell-to-pack ratio",
          "GCTP"
        ],
        "section": "topic-ratings",
        "definition": "The share of a pack’s mass or volume that is cells rather than housing, cooling, busbars and electronics. It is typically 60–75 % by mass; raising it is the point of cell-to-pack and cell-to-chassis designs.",
        "unit": "%",
        "related": [
          "cell-to-pack",
          "specific-energy",
          "pack"
        ],
        "url": "https://lemonergy.com/learn/glossary/cell-to-pack-ratio/",
        "mentions": [
          "cell-to-chassis"
        ]
      }
    },
    {
      "id": "term:thermal-management",
      "type": "Term",
      "label": "Thermal management",
      "properties": {
        "id": "thermal-management",
        "name": "Thermal management",
        "abbr": "TMS",
        "aka": [
          "battery thermal management system",
          "BTMS"
        ],
        "section": "topic-thermal",
        "definition": "Keeping cells in their comfortable range, roughly 15–35 °C, and within a few degrees of each other: liquid cooling plates, refrigerant plates or immersion for heat removal, and heaters or waste heat for warming before fast charging in the cold.",
        "related": [
          "cooling-plate",
          "thermal-interface-material",
          "operating-temperature",
          "heat-generation",
          "preconditioning",
          "temperature-sensor"
        ],
        "url": "https://lemonergy.com/learn/glossary/thermal-management/",
        "mentions": [
          "fast-charging"
        ]
      }
    },
    {
      "id": "term:series-parallel",
      "type": "Term",
      "label": "Series and parallel connection",
      "properties": {
        "id": "series-parallel",
        "name": "Series and parallel connection",
        "aka": [
          "xSyP"
        ],
        "section": "topic-pack",
        "definition": "Cells in series add their voltages; cells in parallel add their capacities and share current. A pack is described as, for example, 96s4p: 96 groups in series, each of 4 cells in parallel. Series strings need balancing; parallel groups self-balance through their shared terminals.",
        "formula": "V = n_s·V_cell, Q = n_p·Q_cell",
        "related": [
          "module",
          "cell-balancing",
          "pack-voltage",
          "volt",
          "fuse"
        ],
        "lesson": "fundamentals/battery-basics/#cell-module-pack",
        "example": {
          "title": "Assemble an ideal 4s2p pack",
          "text": "Eight identical 3.6 V, 5 Ah cells arranged as four series groups with two cells in parallel give 14.4 V nominal, 10 Ah and 144 Wh. Interconnect losses, cell variation and usable voltage limits are additional constraints."
        },
        "url": "https://lemonergy.com/learn/glossary/series-parallel/",
        "mentions": []
      }
    }
  ]
}