IBC Instrument Range 2012

Thermal Hazard Technology

IBC Isothermal Battery Calorimeter

Calorimetry applied to secondary lithium cells Areas of improvement in cells for electric vehicle applications:  Lower cost  Greater energy density  Faster charging and discharging rates  Smaller heat release during use

“Performance” Testing with IBC

 Higher safe operating temperature  Less energy released during decomposition  Better resistance to physical/electrical abuse

“Safety” Testing with ARC

 Should not release hazardous gases during decomposition

MS/GC

Isothermal Calorimetry In Principle  Heat flow (dQ/dt) is the measured parameter  Measured heat flow is measured directly in units of

watts/milliwatts/microwatts  Total heat release is obtained from the integral of

heat flow over time  Sample temperature remains constant (isothermal)

The heart of any calorimeter is the temperature control system. The IBC typically maintains sample temperature to within +/- 0.001 C. At equilibrium, the temperature of the sample cell will be constant and there is no heat flux.

An exothermic process (such as discharging) causes the temperature of the sample to increase. In response, the control algorithm removes power from the sample cell to return and maintain its temperature. The reverse is true for an endothermic response (such as initial charging).

The power added to or removed from the sample is equal to the power absorbed or produced by the sample. The IBC Peltier modules control the sample temperature over the temperature range of –10 C to 80 C. Models for large prismatic cells use a refrigerated circulation system for temperature control and use the peltier elements for heat sensing only. This allows operation at -30 C.

IBC Software Interface • Windows®-based (XP, Vista, 7, 8) • Light-weight, undemanding (works on a netbook) • Simple to use • Separate control and analysis packages

IBC Model Range – Coin Cells to Large Prismatic Cells IBC Model Name

Test Cell Size

Applicable Tests

IBC-CC

Coin cell

Cp, Cycling, Isothermal

IBC

18650, 26650 or larger cylindrical

Cp, Cycling, Isothermal

IBC-P

Small prismatic

IBC-PL

Large prismatic

IBC-SD

Cylindrical

IBC-SD4

Cylindrical (4 samples)

Cp, Cycling, Isothermal Cp, Cycling, Isothermal

Self-discharge Self-discharge

IBC Application: Coin Cells Applications requirements: Low current cycling 50-0.01mA internal cycler High sensitivity 0.1uW sensitivity Heat capacity measurement Automated Cp measurement

Several different diameters and thicknesses of cell Up to 25mm diameter, up to 6mm height

IBC-CC Instrument Data Heat Capacity Test Data

Cycling Test Data

-∆T

+∆T

Coin cell heat capacity = 0.927 J/gK

Cycling to demonstrate battery life-cycle

IBC Application: 18650 Applications requirements: Wide range of currents cycling Connections for external cycler Mix of sensitivity and dynamic range

+/-10W dynamic range, sub mW sensitivity Heat capacity measurement Automated Cp measurement Other sizes of cylindrical cells can be

tested Spacers can provided to meet customer requirement (26650, D cell etc.)

IBC Instrument Data Heat Capacity Test Data

Cycling Test Data

Example Test results: Cell A Cp: 0.83 J/gK

Electrical Energy: 8.96 KJ

Thermal Energy: 0.71 KJ

Efficiency: 92.6%

Cell B Cp: 0.80 J/gK

Electrical Energy: 9.43 KJ

Thermal Energy: 0.35 KJ

Efficiency: 96.4%

IBC Application: Prismatic Cell Applications requirements: High current cycling (up to 100 amps) Low impedance connections to external cycler High dynamic range with decent sensitivity

+/-30W dynamic range, 10mW sensitivity Heat capacity measurement Automated Cp measurement Possibility for low temperature cycling

Refrigerated circulator for -30oC operation Safety features to avoid thermal runaway Cycler cut-out when safe temp is exceeded

IBC-PL Instrument Data Cycling Test Data

50A Discharge at 20oC 4747 Joules of Heat (95 Joules per Amp)

30A Discharge at –10oC 3387 Joules of Heat (113 Joules per Amp)

IBC Application: Self-discharge Applications requirements: Self discharge and accelerated self-discharge Fixed resistance used to for ASD Sensitivity and stability must be very good RMS noise 1µW, stability +/-0.005C, Need to run multiple samples/references Up to 4 samples plus 4 references Operation from ambient to elevated temp Range of operation ambient +5oC – 100oC Low signal drift 0.2µW drift over 1 hour

IBC Users Worldwide