Battery & BMS Validation
EV and energy storage test for safety, accuracy, and lifetime
Overview
Validation workflows for cells, modules, and packs: SOC/SOH accuracy, protection stability, and thermal behavior across operating windows. We combine cycling, IR characterization, and safety tests to reduce field failures.
Industry Challenges
SOC drift under dynamic load and temperature swings
Overcharge/overdischarge protection instability
Internal resistance rise and capacity fade over time
Thermal gradients causing measurement error
Cell imbalance and inconsistent aging
Standards & Specifications
Core Principles
SOC Estimation (Coulomb Counting)
SOC(t) = SOC(t₀) + (1/Qₙ) × ∫I(t)dt × η Where: • Qₙ = Nominal capacity (Ah) • η = Coulombic efficiency (~99.5% for Li-ion) • I > 0 for charge, I < 0 for discharge Drift sources: current offset, temperature, aging Correction: OCV-SOC lookup after rest periods Ref: IEC 62660-1 Annex B
Internal Resistance Measurement
DCIR (pulse method): R_DC = ΔV / ΔI (measured at t = 10s or 18s per standard) ACIR (1kHz typical): Z = V_ac / I_ac at specified frequency EIS (Electrochemical Impedance Spectroscopy): Z(ω) = R_ohmic + R_ct/(1+jωτ) + Z_Warburg IR increases 2-3× from 25°C to -20°C Ref: IEC 62660-1 §7.4, USABC procedures
Heat Generation Model
Total heat: P_total = P_irreversible + P_reversible P_irreversible = I² × R_internal (Joule heating) P_reversible = I × T × (∂OCV/∂T) (entropic heat) For Li-ion: ∂OCV/∂T ≈ -0.2 to +0.5 mV/K (SOC dependent) At high C-rates, Joule heating dominates Ref: J. Electrochem. Soc., Bernardi equation (1985)
Protection Thresholds
Typical thresholds (cell level): • OVP: 4.20-4.35V (Li-ion), hysteresis ~50mV • UVP: 2.50-3.00V, hysteresis ~100mV • OCP: 1-3C continuous, 5-10C pulse • OTP: 45-60°C charge, 60-80°C discharge Response time: <100ms for OCP, <1s for OVP/UVP Ref: UL 2580, GB/T 31485
SOH Definition
Capacity-based SOH: SOH_Q = Q_measured / Q_rated × 100% Resistance-based SOH: SOH_R = (R_EOL - R_current) / (R_EOL - R_BOL) × 100% Power-based SOH: SOH_P = P_available / P_rated × 100% EOL criteria: typically 80% SOH_Q or 200% R increase Ref: ISO 12405-4, SAE J2464
Typical Test Tasks
Charge/Discharge Cycling
- Capacity TestMeasure Q at standard C-rates
- EfficiencyRound-trip energy efficiency over cycles
- Degradation TrackingCapacity vs. cycle count and temperature
- Rest PeriodsOCV relaxation for SOC correction
IR & Pulse Tests
- DCIR vs SOCΔV/ΔI across SOC points
- Temperature SweepIR vs. temperature correlation
- Pulse LoadTransient droop under step current
- Dynamic ProfileDrive-cycle emulation for realism
BMS Protection
- OVP/UVPTrigger thresholds and recovery
- OCP/ShortProtection speed and latch behavior
- Thermal CutoffTrip limits and hysteresis
- Cell BalancingBalance current and equalization time
Data Logging
- Cell VoltageMulti-channel logging with calibration
- Pack CurrentSynchronized current sensing
- TemperatureThermocouple or RTD mapping
- Event MarkersLog protection triggers and resets
Recommended Configuration
Battery Simulator / DC Power Supply
- Bidirectional sourcing/sinking (if needed)
- Remote sense and low noise
- Programmable profiles and telemetry
DC Electronic Load
- Dynamic mode for pulse testing
- Slew rate matched to DUT
- Load profiles for drive cycles
DAQ / Recorder
- Multi-channel voltage/temperature input
- Synchronized sampling
- Long-duration logging
Accessories
- Kelvin clips and low-resistance shunts
- Thermocouples or RTDs with adhesive pads
- Battery-safe harnesses and fusing
- Environmental chamber interface (optional)
Software
- Cycle automation and profile scripting
- SOC/SOH modeling tools
- Data visualization and report templates
Our Services
Test Plan Definition
Profiles for capacity, IR, and protection validation
BMS Algorithm Review
SOC/SOH model tuning and error analysis
Thermal Test Setup
Sensor placement and calibration guidance
Automation & Reporting
Batch testing with automated logs and summaries
Our Capabilities
Cycling & Capacity Tests
Charge/discharge profiles for capacity, efficiency, and degradation
IR & Pulse Characterization
DCIR/ACIR measurement vs. SOC and temperature
BMS Protection Validation
OVP/UVP/OCP trigger and recovery verification
Thermal Correlation
Temperature mapping and correlation to SOC/SOH drift
Recommended Products
Battery Simulators / DC Power Supplies
Bidirectional sourcing with low noise and telemetry
View Products →DC Electronic Loads
Pulse and dynamic discharge profiles
View Products →High-Accuracy DMMs
Voltage/current measurement for SOC/IR calculations
View Products →DAQ / Data Loggers
Multi-channel logging for cell voltages and temperature
View Products →Key Applications
Need a battery/BMS validation setup?
Share your cell chemistry, C-rates, and safety targets. We will propose the right test stack and workflow.