Presentation on theme: "UN 38.3 Lithium-ion Battery Testing"— Presentation transcript:
1UN 38.3 Lithium-ion Battery Testing Vibration and Shock Testing Requirements
2UN 38.3 Lithium-ion Battery Testing Topics Key points of presentationUN 38.3 test overviewUN 38.3 vibration and shock test detailsMild and full hybrid electrical vehicle battery systemsVibration and shock issuesVibration test analysis and recommended changeShock test analysis and recommended changeSummaryBack-upTransportation scenariosCalculationsVibration IsolationAviation shock specification
3UN 38.3 Lithium-ion Battery Testing Requirements KEY POINTS Lithium-ion batteries designed for hybrid electric vehicles (HEV) are large and complicated structures.Lithium-ion HEV batteries are proven to be durable and safe for vehicle usage by extensive testing.Applying the existing vibration and shock requirements to lithium-ion batteries designed for use in HEVs will increase the cost of HEVs and delay the adoption of HEVs in the market.Existing vibration and shock requirements are not valid for heavier lithium-ion HEV batteries.The existing requirements can be modified for large batteries and still assure safe transportation.
4UN T1-T8 Tests UN 38.3 Manual Of Tests T1 – Altitude SimulationT2 – Thermal ShockT3 – VibrationT4 – Physical ShockT5 – External Short CircuitT6 – ImpactT7 – OverchargeT8 – Forced DischargeTests were designed primarily for cell phone and laptop cells and batteries.Tests simulate shipping environment and conditions, not the usage environmentAll tests must be passedTests are without packaging
5UN 38.3 Manual Of Tests T3 Vibration Testing Requirements 16 batteries8 Fully charged4 fresh and 4 with 50 cycles usage8 Discharged3 hrs in each of 3 mutually perpendicular mounting positionsLogarithmic sweep from 7Hz to 200Hz to 7Hz in 15 minutes7Hz to 18Hz at 1gn; amplitude decreasing18Hz to ~50Hz with 0.8mm amplitude; acceleration increasing to 8gn~50Hz to 200Hz at 8gn; amplitude decreasing200Hz to ~50Hz at 8gn; amplitude increasing~50Hz to 18Hz with 0.8mm amplitude: acceleration decreasing to 1gn18Hz to 7Hz at 1gn; amplitude increasing
6UN 38.3 Manual Of Tests Current T4 Shock Testing Requirements 16 batteries8 Fully charged4 fresh and 4 with 50 cycles usage8 Discharged18 shocks: 3 in negative and positive direction of 3 mutually perpendicular mounting positionsShock parametersNormal batteries: Half-sine, 150 gn peak acceleration, seconds pulse durationLarge batteries: Half-sine, 50 gn peak acceleration, seconds pulse durationNote: Large batteries have more than 500 grams ELC
7UN 38.3 Manual Of Tests Pass Criteria for Both Tests No mass lossNo leakage or ventingNo disassemblyNo ruptureNo fireOCV after test > 90% of OCV before test
8HEV Lithium-Ion Batteries Mild and Full Hybrid Applications Mild Hybrid ApplicationsOne electric motorVehicle FunctionsAssist during launch and accelerationStop/start engine when vehicle stopsRegen braking120 volts (32-36 cells)Less than 500Wh14 kg battery assembly400 x 250 x 150 mm16 x 10 x 6 inches
9HEV Lithium-Ion Batteries Mild and Full Hybrid Applications Multiple electric motorsVehicle FunctionAllows electric only propulsionStop/start engine when vehicle stopsRegen brakingvolts (approx cells)Less than 2000Wh45-50 kg battery1000 x 350 x 300mm40 x 14 x 12 inches
10HEV Lithium-Ion Batteries Typical Usage, Vibration and Shock OEM Vehicle Requirements Useful Life: 15 years/ 150,000 milesVibration Test RequirementsRandom vibration1.28 grms10 to 2000 Hz24 hours/axisShock Test RequirementsMild HEV Battery Assembly132 shocks/axis at 25g’s, half-sine, 15 ms6 shocks/axis at 100g’s, 11 msMild and Full HEV Package10 shocks/axis at 50g’s, 6 ms
11HEV Lithium-ion Battery Transportation Prototype or Development StageAir and vehicle modes utilized but mostly vehicleDomestic and internationalMultiple shipments possible for the same battery (some in the vehicle)Batteries have not passed UN 38.3 testingCompetent Authority will be used to allow shippingProductionVessel and vehicle modes normally5 or less shipments of battery before vehicle installationStarts in 2010Must pass UN 38.3 tests or obtain special approval
12UN 38.3 Vibration and Shock Testing Issues and Impact Per Delphi Analysis and Experience:Current battery pack designs for mild and full hybrid applications are expected to fail the T4 vibration testThey may also fail the T3 shock testRedesigning to pass UN vibration and shock tests would add development time, mass and cost to HEV battery systems :That have already met requirements for 15 years of vehicle usageThat will be shipped only a limited number of times and rarely be airImpactHEVs will be more costly to the consumer and possibly delayedAdoption of HEVs will be delayed along with their ecological and energy benefits
13UN 38.3 Vibration and Shock Testing Test Analysis Mild hybrid lithium-ion battery packs are about 14kg gross.Maximum T3 vibration force will be ~27,000N.T4 shock will be ~41,000N.Full hybrid lithium-ion packs are about 48kg gross. It is not a large battery by current definitions.Maximum T3 vibration force will be ~94,000N.T4 shock will be ~141,000N.
14Vibration Test Analysis HEV battery systems are assemblies of electronic controllers, sensors, air flow ducts, cabling, cell mounting fixtures, cells, trays, covers and attachment brackets.They are not “solid” like cells and laptop batteries.They will have several resonant frequencies under 200 Hz.Estimated force exerted on mild HEV batteries due to damping and resonance is approximately 27,000N.Full HEV battery force is approximately 94,000N.With the understanding that vibration test parameters are based on air transportation of small lithium cells and batteries, these parameters do not realistically apply to larger batteries.
15Vibration Test Analysis UN T3 testing of HEV batteries at these frequencies and 8gn is unreasonable because:Vibration of the transportation mode is reduced due to the mass of the pack.Test requires vibration to be “faithfully” transmitted to device, yet vibration would not directly pass from the transportation mode to the battery due to the isolation provided by the skid or container and the package.Force levels can not be transmitted by the transportation modeForce required to vibrate a large notebook computer battery (0.5 kg) is ~1000N.27,000N and 94,000N are very substantial forces2750kg wrecking ball fallingOr stopping a 550kg wrecking ball after falling 1 second (35kph/22mph) in 1 meter9500kg wrecking ball fallingOr stopping a 550kg wrecking ball after falling 1 second in 0.28 meters
16Vibration Test Analysis and Recommendation T3 Test Recommendation For batteries > 12kg:Reduce force level from 8gn to 2gnBasis for recommendationForce levels are more realistic and exceed current exerted forces.Force required to vibrate cell and notebook batteries at 8gn~1000N1000N applied to vibrate a mild hybrid battery is ~0.33g.2gn is equivalent to 5880N for a 12kg pack9 hours of swept-sine vibration testing at 2gn is still a severe test for a large battery.
17Shock Test Analysis and Recommendation T4 shock forces on mild HEV batteries would exceed 40,000N.Full HEV battery forces would be >140,000N.Again, with the understanding that these shock values are based on air transportation of small lithium cells and batteries, these parameters do not realistically apply to larger batteries.UN T4 testing of HEV battery packs at these forces is unreasonable because:These force levels could not be transmitted by the transportation modeForce required to shock cell phone and notebook batteries at 150gn~1500N1500N applied to shock a mild HEV battery (~500Wh, 12Kg) is ~6.5gn.There is no source for the additional 38,000N.Aviation specifications (RTCA) test for Crash Shock at 20g maximum.Recommend limiting acceleration to 50gn for all batteries > 12 kgFar exceeds realistic and expected levels50gn already is used in UN 38.3 for large batteries.
18SummaryMild and full HEVs will have lithium-ion batteries that will have to be tested according to UN 38.3 Manual of TestsUN 38.3 T3 vibration and T4 shock tests are unrealistic when applied to large batteriesIf these tests remain as currently written, conversion of the world vehicle fleet to hybrids will be delayedProposed T3 modification is to reduce g level from 8 to 2 for batteries 12kg or heavierProposed T4 modification is to reduce g level from 150 to 50 for batteries 12kg or heavier
20Back-up HEV Lithium-ion Battery Transportation Scenarios Prototype or Development StageBattery transported from manufacturer to airport by vehicleAirport to airportAirport to distribution center by vehicleDistribution center to HEV system integrator by vehicleHEV system from system integrator to OEM engineering by vehicleHEV (car) from OEM engineering to test site by vehicleHEV (car) back from test site to OEM engineering by vehicleHEV system from OEM engineering back to integrator by vehicleProduction StageBattery transported from manufacturer to marine port by vehicleMarine port to marine portMarine port to distribution center by vehicleHEV system from system integrator to OEM assembly plant by vehicle
21Resonant Vibration Force at 8gn Back-up CalculationsResonant Vibration Force at 8gnForce = [mass] x [acceleration]/[ξ, the damping constant]Damping constant is set at .04, empirical value based on testing similar designsMild Hybrid Force = 14x8x9.8/(.04) N or ~27,000N.Full Hybrid Force = 48x8x9.8/(.04) N or ~94,000N.Shock Force at 150gnForce = [mass] x [acceleration] x Dynamic Amplification FactorDynamic Amplification Factor is set at 2Mild Hybrid Force = 14x150x9.8x2N or ~41,000N.Full Hybrid Force = 48x150x9.8x2N or ~141,000N.
23Stopping a wrecking ball examples: Back-up CalculationsStopping a wrecking ball examples:550kg wrecking ball after falling 1sec in 1 meterForceavg x distance = mass x velocity2/2Forceavg = (mass x velocity2 ) / (2 x distance)Forceavg = 550kg x (9.8m/s)2 / (2 x 1m)Forceavg = kgm/s2Forceavg = 26411N550kg wrecking ball after falling 1sec in 0.28 metersForceavg = 550kg x (9.8m/s)2 / (2 x 0.28m)Forceavg = kgm/s2Forceavg = 94325N
24Back-up CalculationsVibration force required for a large notebook computerForce = [mass] x [acceleration]/[ξ, the damping constant]Damping constant is set at .04Force = .5 x 8 x 9.8/(0.04) ~ 1000N.Acceleration resulting from 1000N vibration force on a 12kg batteryAcceleration = Force x [ξ, the damping constant]/[mass]Acceleration = 1000N x [.04]/12kgAcceleration = 3.33m/sec2 or ~.33gn2gn force applied to a 12kg packForce = 12 x 2 x 9.8/(.04)Force = 5880N
25Force required to shock 0.5kg notebook batteries at 150gn Back-up CalculationsForce required to shock 0.5kg notebook batteries at 150gnForce = [mass] x [acceleration] x Dynamic Amplification FactorForce = 0.5 x 150 x 9.8 x 2NForce ~ 1500NAcceleration resulting from 1500N shock force on a 12kg batteryAcceleration = Force / [mass] / Dynamic Amplification FactorAcceleration = 1500N / 12kg / 2Acceleration = 62.5m/sec2 or ~6.5gn
26Back-up Aviation Equipment Shock Requirements “RTCA, Inc. is a private, not-for-profit corporation that develops consensus-based recommendations regarding communications, navigation, surveillance, and air traffic management (CNS/ATM) system issues. RTCA functions as a Federal Advisory Committee. Its recommendations are used by the Federal Aviation Administration (FAA) as the basis for policy, program, and regulatory decisions and by the private sector as the basis for development, investment and other business decisions.”Source: rtca.org
27Back-up RTCA Specification DO-160D: Environmental Conditions and Test Procedures for Airborne EquipmentShock“Saw Tooth” configuration pulses11ms pulse for standard testing or 20ms for low frequency testing18 shocks, 3 per orientation6gEquipment operatingCrash SafetySame as above except 1 shock/orientation at 20g