EP-WI-014 RevB
Specification for Acceptance Testing of Commercial Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) Cells
Engineering Directorate
Energy Systems Division
July 2000
National Aeronautics and Space Administration
Lyndon B. Johnson Space Center Houston, Texas
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Specification for Acceptance Testing of Commercial Nickel Metal Hydride (NiMH) and Nickel Cadmium (NiCd) Cells
Prepared by: Eric Darcy/EP5 Date SAFER Battery Lead 7/7/00 Power Systems Branch
Original Signed and Approved by
Thomas L. Davies / EP5 Date Chief, Power Systems Branch
Vincent D. Watkins Date Chief, GFE Assurance Branch
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REVISIONS VERSION CHANGES DATE -- Original version June 1998 A 3.2 Relaxed definition of C-rate by inserting an Sept. 1998 approximated C-rate. Table 2. Inserted new column for the Sanyo Fat 4/3A NiMH cell. B 3.2 Added NiCd cell treatment and internal July 2000 resistance measurement and criteria. Table 1. Changed charge rate and duration for NiMH cells for step 4. 3.5 Deleted recording required. 3.6 Deleted recording required. 4.0 Added plots and cell drawing to report. Table 2. Inserted three new rows for two Sanyo NiCd cells and one Sanyo NiMH cell.
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1.0 PURPOSE and SCOPE This document defines how a lot of commercial nickel metal hydride (NiMH) and nickel cadmium (NiCd) cells are accepted and certified for assembly into flight batteries for NASA. This specification is written is accordance with JSC SLP 4.6 “Procurement”. TwoSix cell designs are included in this document in Table 2. The contractor shall procure all cells, serialize them, cycle test them, perform leak checks, re-sleeve them, perform mass and dimensional checks, and deliver them to a NASA-designated site.
2.0 CELL PROCUREMENT The contractor shall procure all cells and obtain a certificate of compliance and material safety data sheet from the source.
3.0 ACCEPTANCE TESTS The following tests shall be performed on every cell. Failure on any test or measurement for which pass/fail criteria are given shall result in rejection of the non-conforming cell. Failure of rates exceeding 15% of lot shall constitute failure of the entire lot unless written exception is made by NASA-JSC. Equipment measuring voltages, temperature, and mass shall be calibrated with equipment traceable to a national standard.
3.1 CELL PREPARATION Once received, all cells shall be stripped of their insulating sleeves, washed as necessary to remove traces of electrolyte residue, and serialized.
CAUTION: Stripped cells should be handled very carefully and be stored in isolating trays or equivalent fixtures.
3.2 CAPACITY AND INTERNAL RESISTANCE The contractor shall cycle each cell according to Table 1. The C-rate shall be approximately based on the manufacturers rated capacity. Note step 1 can omitted if a cell OCV is less than 1.2V.
For NiCd cells, the charge process of step 4 must begin with the cells soaked at 0 C and be completed in a thermal environment convectively controlled to 0 C (-10 C for the high rate subC cell). This procedure will cause high oxygen pressure build-up in the cells because the oxygen recombination kinetics of the cell will be reduced. Allow cells to reach to ambient temperatures before moving on to step 3.
For NiMH cells, the charge process of step 4 is done in an environment at 25 2 C and ambient pressures.
During step 5, the a 100 ms current pulses shall be interrupt the constant current discharge after 30 minute into the discharge. The pulse step shall be at 10C for cells intended for high power density applications and at C/10 for cells intended for high energy density applications. The
internal resistance of the cell, Re, shall determined by Re = V/I. For high rate applications, reject any cell with an Re that is 15% above the average value for the lot.
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Allow cells to return to ambient before resuming cycling with step 3 and 5. Reject any cell not meeting the capacity criteria of Table 2 on step 5.
Table 1. Capacity Cycling Step Type Current Duration 1 Discharge 1C to 1V/cell 2 Charge C/10 16 hours 3 Discharge 1CC 1C to 1V/cell 4 Charge C/3 for NiMH 210 min for NiMH C/10 for NiCd 16 hours for NiCd 5 Discharge 1C to 1V/cell
3.3 LEAK CHECK The contractor shall verify each cell for KOH leaks with phenolphthalein around the crimp seal and seal vent areas. Reject any cell testing positive for leaks.
3.4 REFINISHING The contractor shall refinish the cells with an exterior teflon insulative washer inside the new sleeve according to his cell drawing.
3.5 MASS The contractor shall weigh each cell to within 1 mg. Reject any cell outside the range defined in Table 2.
3.6 DIMENSIONAL Diameter and height of each sleeved cell shall be within the tolerances shown in table 2. The diameter shall be measured at the maximum point along the length of the cell. The height shall be measured along the central axis of the cell at the maximum point. Reject any cells outside the ranges specified in table 2.
3.7 VISUAL Perform a visual inspection of each cell and remove any cell with defects in its sleeving or labeling. Pass/Fail: Damage to a degree which is deemed more than superficial from a mechanical or electrical insulating standpoint.
4.0 REPORTING For each lot subjected to the acceptance tests described herein, a report shall required provided the tabulated results of all tests. A charge/discharge plot of three typical cells during steps 4 and 5 of section 3.2. The contractor’s cell drawings shall also be included in the report.
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Table 2. Pass/Fail Criteria Cell P/N mass (g) length (mm) diameter (mm) capacity (Ah) TH3500SRI-01 52.0 2.0 67.00 +0.00, -1.00 17.00 +0.00, -0.70 3.000 min HR4/3FAUSRI-01 60.0 2.0 67.00 +0.00, -1.00 18.00 +0.00, -0.70 3.300 min HHR210SRI-02 38.0 2.0 50.00 +0.00, -1.50 16.80 +0.00, -0.70 1.600 min N-1900SCR 5456.0 43.00 +0.00, -1.50 23.00 +0.00, -0.70 1.500 min 2.0 KR-1400AE 31.0 2.0 50.00 +0.00, -1.50 17.00 +0.00, -0.70 1.100 min HR4/3AUXSRI-01 5255.0 67.00 +0.00, -1.00 17.00 +0.00, -0.70 3.000 min 2.0
5.0 REFERENCES
JSC SLP 4.6 Procurement JSC SLP 4.20 Statistical Techniques
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