{
  "node": {
    "id": "block:parabolic_film_thickness",
    "type": "Block",
    "label": "parabolic_film_thickness",
    "properties": {
      "id": "parabolic_film_thickness",
      "name": "parabolic_film_thickness",
      "kind": "core",
      "summary": "Square-root film growth relative to an authored reference thickness.",
      "behavior": "Thickness, elapsed time and acceleration factor are nonnegative; reference time is positive. Time units must be consistent. This relation is not an identified SEI, capacity-fade or SOH model.",
      "ports": [
        {
          "name": "return",
          "direction": "output",
          "unit": "same length unit",
          "description": "Scalar float or NumPy array following broadcasting."
        }
      ],
      "parameters": [
        {
          "key": "reference_thickness",
          "label": "reference thickness",
          "unit": "chosen length unit",
          "description": "Nonnegative reference thickness."
        },
        {
          "key": "elapsed_time",
          "label": "elapsed time",
          "unit": "chosen time unit",
          "description": "Nonnegative elapsed time."
        },
        {
          "key": "reference_time",
          "label": "reference time",
          "unit": "same time unit",
          "description": "Positive reference time.",
          "default": 1
        },
        {
          "key": "acceleration_factor",
          "label": "acceleration factor",
          "unit": "dimensionless",
          "description": "Nonnegative multiplier.",
          "default": 1
        }
      ],
      "equations": [
        "delta = delta_ref * sqrt((t / t_ref) * A)"
      ],
      "example": {
        "title": "Explore film growth",
        "text": "At a factor of one, 10 nm at 1 h becomes 20 nm at 4 h and 30 nm at 9 h.",
        "url": "https://lemonergy.com/learn/fundamentals/battery-aging/#sei",
        "label": "Open the worked lesson"
      },
      "limits": [
        "This does not identify SEI chemistry or fit state of health."
      ],
      "evidence": [
        "src/battery_core/aging.py"
      ],
      "caseIds": [
        "film-growth"
      ],
      "type": "parabolic_film_thickness",
      "implementationId": "parabolic_film_thickness",
      "url": "https://lemonergy.com/learn/glossary/blocks/parabolic_film_thickness/",
      "documentationUrl": "https://lemonergy.com/learn/glossary/blocks/parabolic_film_thickness/",
      "sourceFile": "block-library.json",
      "sourceRepository": "battery-core",
      "sourceRevision": "main",
      "reviewed": "2026-10-27"
    }
  },
  "incoming": [
    {
      "id": "edge:usesBlock/film-growth/0",
      "type": "usesBlock",
      "source": "workflow:film-growth",
      "target": "block:parabolic_film_thickness",
      "properties": {
        "sourceFile": "wiki-blocks.json",
        "position": 0,
        "name": "parabolic_film_thickness",
        "type": "parabolic_film_thickness",
        "role": "Core equation",
        "settings": [
          "Reference thickness",
          "Elapsed and reference time",
          "Acceleration factor"
        ]
      }
    }
  ],
  "neighbors": [
    {
      "id": "workflow:film-growth",
      "type": "Workflow",
      "label": "Explore film growth",
      "properties": {
        "id": "film-growth",
        "title": "Explore film growth",
        "kind": "core",
        "summary": "Lemonergy Core evaluates this relation.",
        "steps": [
          "Open the lesson and inspect the equation.",
          "Change one input while holding the others fixed."
        ],
        "example": "At a factor of one, 10 nm at 1 h becomes 20 nm at 4 h and 30 nm at 9 h.",
        "observe": "Compare the result with the equation and units.",
        "limits": "This does not identify SEI chemistry or fit state of health.",
        "url": "https://lemonergy.com/learn/fundamentals/battery-aging/#sei",
        "label": "Open the worked lesson",
        "evidence": [
          "src/battery_core/aging.py"
        ]
      }
    }
  ]
}