1、Lessons Learned Entry: 1410Lesson Info:a71 Lesson Number: 1410a71 Lesson Date: 2004-01-01a71 Submitting Organization: JPLa71 Submitted by: David OberhettingerSubject: In-Flight Passivation of Lithium-Based Spacecraft Batteries (2003) Abstract: A testbed incident affecting the Mars Exploration Rover
2、(MER) flight computer alerted JPL to the consequences of a failure to consider passivation effects on the rovers lithium primary batteries. A passivation-induced voltage transient during a mission critical event could cause PORs, leading to corrupted memory, repeated reboots, and possible loss of mi
3、ssion. Characterize and plan for battery passivation and its effects, and consider designing spacecraft circuitry to tolerate such effects.Description of Driving Event: Passivation is a phenomenon that can affect the performance of lithium batteries. Under no-load conditions, a passivation layer of
4、lithium chloride (LiCl) forms on the surface of the lithium anode and protects the cells from discharging. This effect is responsible for the batterys long shelf life, but the high resistance of the passivation layer may cause the cells voltage to dip during use when a load is applied. As the batter
5、y discharges, the passivation layer dissipates and allows the cell to reach a peak voltage value. Passivation increases along with time and temperature; if the circuit cannot accommodate a voltage delay, the battery pack should be depassivated prior to use.Provided by IHSNot for ResaleNo reproductio
6、n or networking permitted without license from IHS-,-,-refer to D descriptionDA simulated brownout during testing of the Entry, Descent, and Landing (EDL) flight software caused repetitive rebooting of the Mars Exploration Rover (MER) flight computer. A drop in the bus voltage during the simulated t
7、ransition from the solar arrays to the primary batteries in the MER Lander caused the software to erroneously assume that the batteries had failed. The Lander contains five primary (non-rechargeable) lithium sulfur dioxide (LiSO2) batteries to support EDL and initial landed operations. The problem w
8、as traced to a passivation layer inhibiting the Lander batteries from producing full power during the transition (Reference (1). Neither the MER circuit design nor the in-flight battery management procedures allowed for an initial output from the primary batteries (about 25 volts) that was significa
9、ntly less than the 30-volt bus voltage. (Passivation is not usually a concern for secondary (rechargeable) spacecraft batteries because they are in continuous use.) A similar brownout during a mission critical event, such as EDL, could cause power on reset (POR) transients leading to corrupted memor
10、y, repeated reboots, and possible loss of mission.References: Jet Propulsion Laboratory (JPL) Problem/Failure Report No. Z79633, February 28, 2003. Additional Key Words: battery passivation, battery depassivation, RAD6000, VME, battery chemistry, power/pyro subsystemLesson(s) Learned: Assume that a
11、dormant lithium chemistry spacecraft battery will develop a passivation layer and that the effects on the spacecraft circuitry may be significant:a71 Lithium-based spacecraft batteries should be characterized and depassivation measures planned, as requiredProvided by IHSNot for ResaleNo reproduction
12、 or networking permitted without license from IHS-,-,-a71 A standard Department of Defense practice is to characterize and depassivate each spacecraft battery lot- both on the ground and in flight.Recommendation(s): 1. Review the spacecraft power subsystem design for battery passivation effects, cha
13、racterize the spacecraft and mission vulnerability to such effects, and plan for implementation of battery depassivation measures at appropriate mission milestones.2. Conduct ground tests on spacecraft batteries using batteries from the same lot, and test them again in-flight to verify passivation c
14、haracteristics and their effect on voltage output. Assure an adequate supply of spare battery cells.3. Design spacecraft circuitry to tolerate voltage transients from battery passivation effects.Evidence of Recurrence Control Effectiveness: Corrective Action Notice No. Z83898 was opened by JPL on Ma
15、y 11, 2004 to initiate and document appropriate Laboratory-wide corrective action on the above recommendations. (A plan was prepared on September 14, 2004 for documentation of the new method for in-flight battery passivation and for review of future flight projects with primary batteries to ensure d
16、esigns incorporate a depassivation circuit.)Documents Related to Lesson: N/AMission Directorate(s): a71 Exploration Systemsa71 Sciencea71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Flight Equipmenta71 Flight Operationsa71 Ground Equipmenta71 Ground Operationsa71 Hardwarea7
17、1 Packaging Handling Storagea71 Payloadsa71 Risk Management/AssessmentProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71 Safety & Mission Assurancea71 Softwarea71 Spacecrafta71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2004-05-20a71 Approval Name: Carol Dumaina71 Approval Organization: JPLa71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
