IBC

Isothermal

Battery Calorimeter

Thermal Hazard Technology

Calorimetry applied to secondary lithium cells

Areas of improvement in cells for electric vehicle applications:

Lower cost

Greater energy density “Performance”

Faster charging and discharging rates Testing with IBC

Smaller heat release during use

Higher safe operating temperature “Safety”

Less energy released during decomposition Testing with ARC

Better resistance to physical/electrical abuse

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 temperaturecontrol system. The IBC typically maintainssample temperature to within +/- 0.001 C.

At equilibrium, the temperature of the sample cellwill be constant and there is no heat flux.

An exothermic process (such as discharging)causes the temperature of the sample toincrease. In response, the control algorithmremoves power from the sample cell to returnand maintain its temperature. The reverse is truefor an endothermic response (such as initialcharging).

The power added to or removed from the sample is equal to the power absorbed orproduced by the sample. The IBC Peltier modules control the sample temperature over thetemperature range of –10 C to 80 C.

Models for large prismatic cells use a refrigerated circulation system for temperature controland 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

IBC18650, 26650 or larger

cylindrical

Cp, Cycling, Isothermal

IBC-PSmall prismatic

Cp, Cycling, Isothermal

IBC-PL Large prismaticCp, Cycling, Isothermal

IBC-SD CylindricalSelf-discharge

IBC-SD4 Cylindrical (4 samples)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

-∆T

+∆T

Heat Capacity Test Data Cycling Test Data

Coin cell heat capacity = 0.927 J/gK Cycling to demonstrate battery life-cycle

IBC Application: 18650Applications 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 DataHeat 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 DataCycling Test Data

30A Discharge at

–10oC

3387 Joules of

Heat

(113 Joules per

Amp)

50A Discharge at

20oC

4747 Joules of

Heat

(95 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