{
  "last_updated": "2026-01-18T22:38:39.761Z",
  "version": "2026-01-18",
  "changelog_url": "https://evolvebattery.us/data/changelog",
  "facts": [
    {
      "key": "contactor",
      "label": "Contactor",
      "value": "An electrically controlled switch designed to handle high DC voltages and currents in battery systems. Contactors provide the main disconnect mechanism for isolating the battery pack from the load.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/contactor"
      ]
    },
    {
      "key": "precharge-circuit",
      "label": "Precharge Circuit",
      "value": "A circuit that limits inrush current when initially energizing high-voltage bus capacitors by using a current-limiting resistor in series with a bypass contactor.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/precharge-circuit"
      ]
    },
    {
      "key": "hvil",
      "label": "HVIL (High-Voltage Interlock Loop)",
      "value": "A safety circuit that monitors the physical integrity of all high-voltage connections. If any HV connector is disconnected, the HVIL circuit opens, triggering immediate system shutdown.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/hvil"
      ]
    },
    {
      "key": "isolation-monitoring",
      "label": "Isolation Monitoring",
      "value": "Continuous measurement of electrical resistance between high-voltage conductors and chassis ground to detect insulation faults before they become hazardous.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/isolation-monitoring"
      ]
    },
    {
      "key": "bus-capacitor",
      "label": "Bus Capacitor",
      "value": "Large capacitors placed on the high-voltage bus to stabilize voltage during transient loads and provide local energy storage for high-frequency power demands.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/bus-capacitor"
      ]
    },
    {
      "key": "arc-flash",
      "label": "Arc Flash",
      "value": "An electrical explosion caused by rapid release of energy during a short circuit or disconnect under load in high-voltage DC systems. Extremely dangerous due to intense heat and pressure wave.",
      "category": "high-voltage",
      "source_pages": [
        "https://evolvebattery.us/glossary/arc-flash"
      ]
    },
    {
      "key": "bms",
      "label": "BMS (Battery Management System)",
      "value": "Electronic system that monitors and manages battery pack operation, including cell voltage monitoring, temperature sensing, current measurement, state estimation, and safety protection.",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/bms"
      ]
    },
    {
      "key": "soc",
      "label": "SOC (State of Charge)",
      "value": "Estimate of remaining battery capacity expressed as a percentage of total usable capacity. Analogous to a fuel gauge in vehicles.",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/soc"
      ]
    },
    {
      "key": "soh",
      "label": "SOH (State of Health)",
      "value": "Estimate of battery degradation relative to new condition, typically expressed as percentage of original capacity or power capability remaining.",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/soh"
      ]
    },
    {
      "key": "cell-balancing",
      "label": "Cell Balancing",
      "value": "Process of equalizing charge across cells in a series string by redistributing charge (active balancing) or dissipating excess charge as heat (passive balancing).",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/cell-balancing"
      ]
    },
    {
      "key": "can-bus",
      "label": "CAN Bus (Controller Area Network)",
      "value": "Multi-master serial communication protocol designed for reliable communication in automotive and industrial environments. Common interface for BMS communication.",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/can-bus"
      ]
    },
    {
      "key": "coulomb-counting",
      "label": "Coulomb Counting",
      "value": "Method of estimating state-of-charge by integrating current flow over time (1 coulomb = 1 ampere-second). Primary technique used by BMS for SOC estimation.",
      "category": "bms-communication",
      "source_pages": [
        "https://evolvebattery.us/glossary/coulomb-counting"
      ]
    },
    {
      "key": "thermal-runaway",
      "label": "Thermal Runaway",
      "value": "Self-accelerating exothermic reaction in a lithium-ion cell where internal heat generation exceeds heat dissipation, leading to rapid temperature rise, gas generation, and potential fire.",
      "category": "thermal",
      "source_pages": [
        "https://evolvebattery.us/glossary/thermal-runaway"
      ]
    },
    {
      "key": "thermal-interface-material",
      "label": "Thermal Interface Material (TIM)",
      "value": "Material placed between heat-generating components and heat sinks to improve thermal conductivity by filling microscopic air gaps. Common types include thermal paste, pads, and phase-change materials.",
      "category": "thermal",
      "source_pages": [
        "https://evolvebattery.us/glossary/thermal-interface-material"
      ]
    },
    {
      "key": "cold-plate",
      "label": "Cold Plate",
      "value": "Heat exchanger with internal liquid coolant channels designed to remove heat from battery modules through conduction. Typically aluminum or copper construction.",
      "category": "thermal",
      "source_pages": [
        "https://evolvebattery.us/glossary/cold-plate"
      ]
    },
    {
      "key": "convection-cooling",
      "label": "Convection Cooling",
      "value": "Heat transfer method using fluid flow (air or liquid) over surfaces to remove heat. Natural convection relies on buoyancy; forced convection uses fans or pumps.",
      "category": "thermal",
      "source_pages": [
        "https://evolvebattery.us/glossary/convection-cooling"
      ]
    },
    {
      "key": "conduction-cooling",
      "label": "Conduction Cooling",
      "value": "Heat transfer through direct contact between solid materials. Primary mechanism for moving heat from battery cells to cooling system.",
      "category": "thermal",
      "source_pages": [
        "https://evolvebattery.us/glossary/conduction-cooling"
      ]
    },
    {
      "key": "overcharge",
      "label": "Overcharge",
      "value": "Condition where a lithium-ion cell voltage exceeds its maximum safe voltage, causing electrolyte decomposition, lithium plating, gas generation, and potential thermal runaway.",
      "category": "safety-testing",
      "source_pages": [
        "https://evolvebattery.us/glossary/overcharge"
      ]
    },
    {
      "key": "short-circuit",
      "label": "Short Circuit",
      "value": "Unintended low-resistance path that allows excessive current flow, potentially causing rapid heating, component damage, and fire. Can be internal to a cell or external.",
      "category": "safety-testing",
      "source_pages": [
        "https://evolvebattery.us/glossary/short-circuit"
      ]
    },
    {
      "key": "fmea",
      "label": "FMEA (Failure Modes and Effects Analysis)",
      "value": "Systematic methodology for identifying potential failure modes in a system, assessing their severity and likelihood, and implementing mitigation strategies.",
      "category": "safety-testing",
      "source_pages": [
        "https://evolvebattery.us/glossary/fmea"
      ]
    },
    {
      "key": "wire-bonding",
      "label": "Wire Bonding",
      "value": "Cell interconnection method using multiple small-diameter aluminum or copper wires ultrasonically welded to cell terminals. Provides flexible, low-stress connection.",
      "category": "mechanical",
      "source_pages": [
        "https://evolvebattery.us/glossary/wire-bonding"
      ]
    },
    {
      "key": "tab-welding",
      "label": "Tab Welding",
      "value": "Cell interconnection method using resistance or laser welding to attach nickel tabs or bus bars to cell terminals. Common for prismatic and pouch cells.",
      "category": "mechanical",
      "source_pages": [
        "https://evolvebattery.us/glossary/tab-welding"
      ]
    },
    {
      "key": "energy-density",
      "label": "Energy Density",
      "value": "Energy storage capacity per unit mass (Wh/kg, gravimetric) or per unit volume (Wh/L, volumetric). Key performance metric for mobile applications.",
      "category": "mechanical",
      "source_pages": [
        "https://evolvebattery.us/glossary/energy-density"
      ]
    },
    {
      "key": "power-density",
      "label": "Power Density",
      "value": "Power delivery capability per unit mass (W/kg) or volume (W/L). Critical for applications requiring high acceleration or peak power.",
      "category": "mechanical",
      "source_pages": [
        "https://evolvebattery.us/glossary/power-density"
      ]
    },
    {
      "key": "c-rate",
      "label": "C-Rate",
      "value": "Measure of charge or discharge current relative to battery capacity. 1C means the battery is fully discharged in 1 hour; 2C means 30 minutes.",
      "category": "cells-chemistry",
      "source_pages": [
        "https://evolvebattery.us/glossary/c-rate"
      ]
    },
    {
      "key": "cycle-life",
      "label": "Cycle Life",
      "value": "Number of charge-discharge cycles a battery can complete before capacity degrades to a specified percentage (typically 80%) of original capacity.",
      "category": "cells-chemistry",
      "source_pages": [
        "https://evolvebattery.us/glossary/cycle-life"
      ]
    },
    {
      "key": "depth-of-discharge",
      "label": "Depth of Discharge (DOD)",
      "value": "Percentage of battery capacity that has been discharged relative to total capacity. 80% DOD means 80% of capacity used, 20% remaining.",
      "category": "cells-chemistry",
      "source_pages": [
        "https://evolvebattery.us/glossary/depth-of-discharge"
      ]
    },
    {
      "key": "nominal-voltage",
      "label": "Nominal Voltage",
      "value": "Representative voltage of a battery cell or pack, typically near mid-point of discharge. For lithium-ion cells, typically 3.6V or 3.7V depending on chemistry.",
      "category": "cells-chemistry",
      "source_pages": [
        "https://evolvebattery.us/glossary/nominal-voltage"
      ]
    },
    {
      "key": "internal-resistance",
      "label": "Internal Resistance",
      "value": "Total opposition to current flow within a battery cell, including ionic resistance in electrolyte and electronic resistance in electrodes and current collectors. Increases with age and low temperature.",
      "category": "cells-chemistry",
      "source_pages": [
        "https://evolvebattery.us/glossary/internal-resistance"
      ]
    },
    {
      "key": "continuous-power",
      "label": "Continuous Power",
      "value": "Maximum power that a battery system can sustain indefinitely without thermal limiting or degradation. Typically limited by thermal management capability.",
      "category": "power-energy",
      "source_pages": [
        "https://evolvebattery.us/glossary/continuous-power"
      ]
    },
    {
      "key": "peak-power",
      "label": "Peak Power",
      "value": "Maximum instantaneous power capability, typically limited by cell discharge capability and voltage sag. Usually specified with duration (e.g., 10-second peak).",
      "category": "power-energy",
      "source_pages": [
        "https://evolvebattery.us/glossary/peak-power"
      ]
    },
    {
      "key": "discharge-profile",
      "label": "Discharge Profile",
      "value": "Time-varying pattern of current or power draw from a battery during operation. Can be constant, pulsed, or variable depending on application.",
      "category": "power-energy",
      "source_pages": [
        "https://evolvebattery.us/glossary/discharge-profile"
      ]
    }
  ]
}