Transcript EVS-11-18ex

EVS-11-18e
Li-ion Batter y Safety
NHTSA Research Update
GTR (June 2016)
Stephen Summers
Chief
Crashworthiness Research
2016 Ongoing Argonne N.L.
Charging System – BMS System Safety Testing
Compliment research from prior project with qualified 3rd party validation data.
Critique of the procedures and expand to include AC charging and study the
applicability to other interfaces.
Critique of DC test procedure developed under NHTSA Research (SAE J1772
combo)
Validation Test of the procedure (BMW i3)
Document an AC equivalent procedure with validation (SAE J1772 Combo)
Document an equivalent procedure (CHAdeMO – paper study only)
2016 Ongoing Argonne N.L.
Shor t Circuit Testing – Soft to Hard (50mΩ - 1mΩ)
Develop and document short-circuit test procedures including system
boundary requirements necessary for proper safety testing. Include the
complete range of potential short circuit (over-current) conditions in the analysis.
Standards. Prepare recommendation for regulatory consideration.
Research and compare test methods and BMS diagnostic capabilities to
existing state-of-technology and best practices to identify areas for improvement.
Note: Novel test methods are being considered using correlated CAN data to
properly bound impedance boundaries to be tested on each application.
2016 Ongoing Argonne N.L.
Sequential Testing Review and Critique
Review the sequential BMS test procedures documentation and identify areas
to improve tests for simplicity and accuracy, and in addition identify areas not
covered in the report.
NOTE: ANL is leveraging their extensive vehicle test data base which was
developed through testing sponsored by the DOE (2008-present)
Several areas have been identified which may be simplified recommended
for improvement, including but not limited to:
BMS Operational Protection to prevent Over-Charge
BMS Ground Fault and Isolation Tests
BMS Over-Discharge protection and verification Test
Additional engineering resources have deployed by ANL
to expedite this area of the NHTSA research project
2016-2017 Ongoing Sandia N.L. & Naval Surface Warfare Center
Propagation Test – Initiation/ Provocation Development
Research and develop a robust thermal initiation method that represents the
chemical and electrical heat release of a single cell in thermal decomposition.
Characterization of cells to quantify minimal input thermal for provocation
Define method
Development of heater to provoke without exceeding a single cells’ thermal
Limitation based on characterization (above)
Variation boundaries and adaptation (cell structure )
Validation
Cell/Module/Pack
4th Quarter 2016 – 2nd Quarter 2017 - Argonne N.L.
Par tial Immersion – Design of experiments
Research the effects of a REESS system simulating damage from a vehicle
crash that is partially exposed to brackish (1.75% NaCl) or salt water (3.5% NaCl)
Pack Level DUT
50% immersion (intentionally leaving some cells/modules above the waterline
• damaged enclosure – allowing water to flow-in
• non-damaged enclosure – as designed by OEM
3.5% NaCl
1.75% NaCl
2014 – Present
Sandia and Idaho N.L.
Batter y State-of-Health and Stability Diagnostic
Tool Set Development
Research and develop embeddable technology to determine the safety related
health and stability of a Li-ion based RESS, particularly in one which has lost
communication or has been isolated as in the case of a vehicle crash, or post
crash circumstance.
Imaginary impedance (ohm)
-0.0002
-0.00015
-0.0001
-0.00005
0
0.001
0.002
25C
0.003
0.004
0.005
Real impedance
75C
125C
2014 – Present
Sandia and Idaho N.L.
Batter y State-of-Health and Stability Diagnostic
Tool Set Development
Research and develop embeddable technology to determine the safety related
health and stability of a Li-ion based RESS, particularly in one which has lost
communication or has been isolated as in the case of a vehicle crash, or post
crash circumstance.
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Rapid spectrum measurement (10 seconds)
Design compatible with in-situ applications
Limited frequency range (.0125 to 2k Hz)
Limited frequency resolution (octave steps)
Range and resolution traded for speed (one period of lowest frequency)
Based on Harmonic Compensated Synchronous Detection (HCSD)
2014 – Present
Sandia and Idaho N.L.
Batter y State-of-Health and Stability Diagnostic
Tool Set Development
• Based on Harmonic Compensated Synchronous Detection (HCSD)
• Sum of Sines (SOS) current excites battery with one period of lowest
frequency
• SOS octave frequency steps
• Captured voltage waveform synchronously detected at each frequency
• Validated with Electrochemical Impedance Spectroscopy (EIS)
2014 – Present
Sandia and Idaho N.L.
Batter y State-of-Health and Stability Diagnostic
Tool Set Development
• Validation complete using a 5 V IMB (single cell) 1P, 2P, 3P, 4P
• 50 V IMB in place and testing ongoing (3S1P, 3S2P, 3S4P)
• 300V IMB in development
Uses:
• On-board safety assessment
• Compliance test pass/fail criteria (simpler and more performance based)
• Safety in handling
QUESTIONS?