{
  "node": {
    "id": "term:reduced-order-model",
    "type": "Term",
    "label": "Reduced-order model",
    "properties": {
      "id": "reduced-order-model",
      "name": "Reduced-order model",
      "abbr": "ROM",
      "aka": [
        "model order reduction"
      ],
      "section": "topic-transport",
      "definition": "A simplified version of a detailed model that keeps its dominant behaviour with far fewer states. The single-particle model is one reduction of the Newman model; others use polynomial profiles, Padé approximation or proper orthogonal decomposition. A ROM gives a BMS internal quantities, such as lithium concentration in the electrodes, that an equivalent circuit model cannot.",
      "related": [
        "newman-model",
        "single-particle-model",
        "state-space-model",
        "equivalent-circuit-model",
        "bms"
      ],
      "url": "https://lemonergy.com/learn/glossary/reduced-order-model/",
      "mentions": [
        "reduction"
      ]
    }
  },
  "edges": [
    {
      "id": "edge:168",
      "source": "term:reduced-order-model",
      "target": "workflow:rc-response",
      "type": "usedIn",
      "properties": {
        "sourceFile": "wiki-blocks.json"
      }
    },
    {
      "id": "edge:4798",
      "source": "term:reduced-order-model",
      "target": "topic:topic-transport",
      "type": "belongsTo",
      "properties": {
        "sourceFile": "terms.json"
      }
    },
    {
      "id": "edge:4799",
      "source": "term:reduced-order-model",
      "target": "term:newman-model",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4800",
      "source": "term:reduced-order-model",
      "target": "term:single-particle-model",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4801",
      "source": "term:reduced-order-model",
      "target": "term:state-space-model",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4802",
      "source": "term:reduced-order-model",
      "target": "term:equivalent-circuit-model",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:4803",
      "source": "term:reduced-order-model",
      "target": "term:bms",
      "type": "relatedTo",
      "properties": {
        "sourceFile": "terms.json",
        "meaning": "Related context; not a causal claim"
      }
    },
    {
      "id": "edge:mentions/reduced-order-model/reduction",
      "source": "term:reduced-order-model",
      "target": "term:reduction",
      "type": "mentions",
      "properties": {
        "sourceFile": "terms.json",
        "method": "build_glossary.mention_index + mentions",
        "field": "definition",
        "meaning": "Text mention; not a causal claim"
      }
    }
  ],
  "neighbors": [
    {
      "id": "workflow:rc-response",
      "type": "Workflow",
      "label": "Observe an RC time constant",
      "properties": {
        "id": "rc-response",
        "title": "Observe an RC time constant",
        "kind": "studio",
        "summary": "An RC circuit uses source, resistor, capacitor and reference blocks.",
        "steps": [
          "Keep R = 1 Ω and C = 1 F.",
          "Inspect capacitor voltage after one and two time constants."
        ],
        "example": "From zero initial voltage with a 1 V step, ideal capacitor voltage is about 0.632 V at 1 s and 0.865 V at 2 s.",
        "observe": "Doubling resistance or capacitance doubles the time constant.",
        "limits": "This generic circuit does not identify cell parameters from measurements.",
        "url": "https://design.lemonergy.com/cosim.html?example=physical-rc",
        "label": "Open the RC example",
        "evidence": [
          "js/physical-network.js",
          "js/studio-examples.js"
        ]
      }
    },
    {
      "id": "topic:topic-transport",
      "type": "Topic",
      "label": "Transport and modelling",
      "properties": {
        "id": "topic-transport",
        "name": "Transport and modelling",
        "lede": "How ions move, and the equations and models that describe a cell.",
        "context": "Specify phase, direction and boundaries.",
        "example": "The same concentration difference across 10 μm gives ten times the gradient across 100 μm; at equal D, first-law flux magnitude is ten times greater.",
        "lesson_url": "https://lemonergy.com/learn/transport/ficks-first-law/",
        "lesson_label": "Open diffusion"
      }
    },
    {
      "id": "term:newman-model",
      "type": "Term",
      "label": "Newman model",
      "properties": {
        "id": "newman-model",
        "name": "Newman model",
        "abbr": "P2D",
        "aka": [
          "pseudo-two-dimensional model",
          "Doyle–Fuller–Newman",
          "DFN"
        ],
        "section": "topic-transport",
        "definition": "The standard physics-based lithium-ion cell model: porous-electrode theory across the cell thickness, with solid diffusion solved in a representative spherical particle at every point — hence pseudo-two-dimensional. It predicts voltage from first principles but needs dozens of parameters.",
        "related": [
          "porous-electrode-theory",
          "single-particle-model",
          "butler-volmer",
          "ficks-second-law",
          "parameterisation",
          "pybamm"
        ],
        "url": "https://lemonergy.com/learn/glossary/newman-model/",
        "mentions": [
          "diffusion"
        ]
      }
    },
    {
      "id": "term:single-particle-model",
      "type": "Term",
      "label": "Single-particle model",
      "properties": {
        "id": "single-particle-model",
        "name": "Single-particle model",
        "abbr": "SPM",
        "section": "topic-transport",
        "definition": "A simplified physics model that represents each electrode as one spherical particle and neglects electrolyte gradients. It runs fast enough for a BMS and is accurate at low to moderate currents.",
        "related": [
          "newman-model",
          "equivalent-circuit-model",
          "solid-state-diffusion",
          "bms"
        ],
        "url": "https://lemonergy.com/learn/glossary/single-particle-model/",
        "mentions": [
          "electrode",
          "electrolyte"
        ]
      }
    },
    {
      "id": "term:state-space-model",
      "type": "Term",
      "label": "State-space model",
      "properties": {
        "id": "state-space-model",
        "name": "State-space model",
        "aka": [
          "state-space representation"
        ],
        "section": "topic-transport",
        "definition": "A model written as first-order equations for a set of internal states — such as state of charge and the voltages across RC pairs — plus an output equation for the measured terminal voltage. Kalman filters and other observers need this form, so equivalent circuit and reduced physics models are cast this way for a BMS.",
        "formula": "ẋ = A·x + B·u; y = C·x + D·u",
        "related": [
          "kalman-filter",
          "equivalent-circuit-model",
          "rc-pair",
          "reduced-order-model",
          "state-of-charge"
        ],
        "example": {
          "title": "Read a one-state thermal model",
          "text": "Let x be temperature rise and u heating power. With ẋ = −0.01x + 0.002u, the time constant is 100 s and a steady 10 W input gives x = 2 K. The output y = x directly reports temperature rise."
        },
        "url": "https://lemonergy.com/learn/glossary/state-space-model/",
        "mentions": [
          "voltage",
          "bms"
        ]
      }
    },
    {
      "id": "term:equivalent-circuit-model",
      "type": "Term",
      "label": "Equivalent circuit model",
      "properties": {
        "id": "equivalent-circuit-model",
        "name": "Equivalent circuit model",
        "abbr": "ECM",
        "aka": [
          "Thevenin model"
        ],
        "section": "topic-transport",
        "definition": "A cell model built from a voltage source for OCV, a series resistor and one or more RC pairs for the slower dynamics. Its few parameters are fitted from pulse tests, and it is what most battery management systems run in real time.",
        "related": [
          "rc-pair",
          "open-circuit-voltage",
          "hppc",
          "kalman-filter",
          "single-particle-model"
        ],
        "url": "https://lemonergy.com/learn/glossary/equivalent-circuit-model/",
        "mentions": []
      }
    },
    {
      "id": "term:bms",
      "type": "Term",
      "label": "Battery management system",
      "properties": {
        "id": "bms",
        "name": "Battery management system",
        "abbr": "BMS",
        "section": "topic-pack",
        "definition": "The electronics and software that keep a battery inside its safe window: measuring every cell voltage and many temperatures, estimating SOC and SOH, balancing cells, computing current limits, controlling the contactors and reporting over the vehicle network.",
        "related": [
          "state-of-charge",
          "cell-balancing",
          "state-of-power",
          "cell-supervision-circuit",
          "contactor",
          "can-bus"
        ],
        "lesson": "fundamentals/battery-basics/#cell-module-pack",
        "url": "https://lemonergy.com/learn/glossary/bms/",
        "mentions": [
          "state-of-health",
          "cell-voltage"
        ]
      }
    },
    {
      "id": "term:reduction",
      "type": "Term",
      "label": "Reduction",
      "properties": {
        "id": "reduction",
        "name": "Reduction",
        "section": "topic-electrochemistry",
        "definition": "Gain of electrons by a species. On discharge the positive electrode is reduced as it takes up lithium ions and electrons, which is why it is called the cathode.",
        "related": [
          "oxidation",
          "cathode",
          "redox-reaction"
        ],
        "url": "https://lemonergy.com/learn/glossary/reduction/",
        "mentions": [
          "electrode",
          "positive-electrode"
        ]
      }
    }
  ]
}