The Nickel Cadmium 129-ampere hour cell was tested in order to characterize the cell under controlled conditions. Results of charge characterization and discharge characterization are reported. Ampere hour efficiency, open circuit stand, and cycle life operation results are included. The battery is briefly described

Lear, J. W.

English

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'h. 
POCKET  NICKEL CADMIUM CELL AND  BATTERY  EVALUATION 
J.  Lear 
Martin  Marietta 
The  pocket NiCad battery  has  been  around  for  a  long  time,  and  I wish to thank  Floyd  and 
Jerry  for  permitting  me to  present  this  at  this  workshop.  Since  this is  a workshop, it is nice to 
present it. 
The reason why I would like t o  present  this  paper is that we were looking  at  a  military 
application that required  a  battery,  not an aerospace-type battery, but a NiCad battery  for  a 
military  application.  Nife  Corporation  of  Lincoln,  Rhode  Island  and  Sweden,  loaned us 22 cells 
to  test. 
Since  there  is  such  a  small  data  base  on  this  particular  battery  and  it  had  never  been  tested in 
a  military  application, I thought  it was an  excellent  opportunity to  test  it'and  to  present  some  of 
the  results  that  I  got  during  this  testing. 
(Figure  4-95) 
The  purpose  of  the  test was to  evaluate the 129-ampere hour cell to characterize  the cell 
under  controlled  conditions.  One  test is missing there. It was  an open-circuit  stand  test  which  I will 
talk  about  on  the  next  chart. 
(Figure  4-96) 
Again, Nife loaned us 22 cells of which five modules were monoblocks, five and six-cell 
monoblocks, and we divided them up into various tests. We had five of them on charge 
characterization, which later  on we went  into  ampere-hour  efficiency  tests. 
We put five on discharge characterization; we had five on  open  circuit  stand,  and  there were 
six that  just  sat  open  circuit  with  nothing going on. 
(Figure  4-97) 
This  is  a  little  bit  of  a  description of the cell. You can see i t  is  a big hummer,  not a small guy 
It is 15 inches tall and weighs roughly 15 pounds.  The  resistance  you will notice I have scratched 
out  there.  Nife was nice  enough to give me  some  updated  information.  It is 1.1  milliohms. 
(Figure 4-98) 
3 77 
https://ntrs.nasa.gov/search.jsp?R=19800012367 2020-03-21T18:19:00+00:00Z
We have  27-cubic  foot  test  chambers  at  Martin  Marietta. You can see that’s a five-cell 
monoblock,  and  you  can  see  how  much  space  it  takes  up  in  the  cube  itself.  The  total 22-cell battery 
weighed 330 pounds.  I  don’t  expect  you to run  out  and  put  it  in  a  spacecraft. 
(Figure 4-99) 
This is a  drawing  that was put  together  by  myself  and an illustrator  at  Martin  showing  the 
way  a  pocket NiCad plate  is  designed,  put  together  or  manufactured.  At  the  top is a roll of  metal 
steel  which  is 0.1  millimeters  thick.  It runs through  a  punch  press  that  has  needles  that  punches on 
either side of the plate, and you come out with a form plate that has got holes all perforated 
through  it. 
Previously, the  method was to  punch holes on one side.  But  now  they are punching holes on 
both sides  which gives them 30 percent  more  area  for  the  electrolyte to  flow through  the  plate. 
Little  briquets are then placed within  the  stamped  plates. As you can  see here,  the edges  are 
folded  over  and they interweave. When the  plate is all put  together,  they  are  a  nice,  solid  mesh 
plate.  Both  the  positive  and negative plates  are  made  this  way. 
(Figure 4- 100) 
You will notice  that  the  manufacturer  recommended  voltage  limits  on  the  right-hand  column. 
This  data was generated  after we  had  already  got  into  our  tests, well along into  our  tests,  and we 
had  made  some  assumptions  along  the way that  terminate  the voltages at  the selected voltages 
there.  And we  charge the cells at various rates; 5, 10, 15, and  25  amperes  constant  current  until 
either  a voltage limit  cutoff  or  a  time  cutoff. 
You will see  later  on  that  under  the  minus 10 condition,  I  have  made  an  error in selecting the 
voltages. I did not  know  what  the voltage cutoff was or  recommended. I had  arbitrarily  picked a 
number. 
(Figure 4- I 0 1 ) 
Here is the  result. You will see at  the  plus  40-  and  plus 25-degree state  during  the  charge 
categorization  test,  that  for  the  5, 10 through  the  25, we did  get  roughly 140 to 150  ampere-hours 
of  capacity out of the cells. 
But  in  the  minus 10 condition,  because  I had made  an  error in judgment of  picking too  low, 
we  did not get  full state  of charge. It is not  the problem  with  the  battery  but was a  problem  with 
me. So, I  didn’t have anything  to base my judgment  on,  and  I  just  went  ahead and  picked  a  number. 
(Figure 4- 102) 
This is some  of  the  typical charge characteristic curves that I have got. These charges 
represent the  capacity  that  I  took  out  on  a  previous  charge  at  the  various  temperatures.  In  other 
3 78 
words,  if  you  look  at  the 25-degree  charge  here,  I  took  out  roughly  130  ampere-hours  of  capacity 
out   o f  the cell at  the  particular  test,  and  that's  what I put  back  in. 
This  is  where I went  into  the gas evolution. You will notice I took out  roughly 80 to 90 
ampere-hours  of  capacity  at  that  minus  10-  and  40-degree  test. 
(Figure 4- 103) 
The  discharge  characterization is just  a  normal  nice,  smooth  curve  indicative  of  the  nickel- 
cadmium  system. I just  wanted  you to see  what  the  curves  looked  like  as  I  saw  them  during  the 
tests. 
(Figure 4- 104) 
Ampere-hours  efficiency  for  the  three  charge  conditions I was  working  with.  It  turned  out  I 
was  operating  somewhere  between 55- and  95-percent  ampere-hours  efficiently  through  the  charge 
characterization tests. It was 
terrestrial  applications. 
(Figure 4- 105) 
For  open-circuit  stand, 
that  we  took.  Periodically  we 
a very excellent system for ground operations communications or 
we went  actually  240  days,  but  I  plotted  out  200. We had  six  cells 
would  discharge  them. 
During  the  initial  characterization  test,  we  checked  out  the  capacity,  and  we  have got for  the 
22 cells,  an  average of  150.25  ampere-hours  out  of  129-ampere  hour cells,  which  indicated  we  had 
like  a  17-percent  excess  capacity  above  the  nameplate  capacity. 
Again, the cells  had  never  been  tested to  my  knowledge, I don't  think to Nife's  knowledge, in 
this  type  of  a  regime. So they also  were  a  little  bit  elated  with  some  of  the  data  that  we  got  for 
them. 
(Figure 4- 106) 
The five-cell was monoblock  that  I  had  for  discharge  characterization  test.  Nife  and I d o   n o t  
see  eye to eye  on  this  (they  are  in  the  crowd,  and  they  may  expound  on  that  later  on),  but  when  we 
did  the  characterization  test, I left  some of the cells  sitting  around  in  open-circuit  charge. Five of 
the cells,  (this  particular  monoblock),  were  low  in  electrolyte,  and  for  some  reason,  the  capacity 
was  low  when  we  went to test  them. I do   no t  have  an  explanation  for  it.  Nife  may  offer  some 
answer.  I do  not  have  an  answer  on  that.  I will let  it  go  at  that. 
(Figure  4- 107) 
For  terrestrial  application,  ground  power  communications,  the  system is excellent.  It  offers 
an  excellent  capacity  over  wide  operating  range  and  a  large  temperature  range.  Higher  cutoff  voltage 
3 79 
was  required,  as I showed  you. I had  picked the wrong  number.  Since  then  Nife  has  come  out  and 
has  come  up  with  a  set  of  limits  that we can  work  with  in  a  military-type  application.  Reasonable 
ampere-hour  efficiency is afforded  with  this  system. 
Through  the  open-circuit  stand  time, we have  only  lost 3 percent  a  month. I think we only 
went  down  like 25 percent  in 200 days.  That’s my results. 
DISCUSSION 
VOICE: How large was the  pocket? 
LEAR: How large was the  pocket?  129  ampere-hours. 
3 80 
INTRODUCTION:  TEST AND EVALUATION  OF 129 A h r  POCKET  PLATE 
NICKEL  CADMIUM  CELLS/BATTERY I N  SUPPORT OF 
I l I L I T A R Y   A P P L I C A T I O N .  
OBJECTIVE:  TO  CHARACTERIZE  TH   ENERGY  STORAGE  SYSTEM UNDER 
CONTROLLED  CONDITIONS. 
SCOPE : o CHARGE CHARACTERIZATION 
o AMPERE HOUR E F F I C I E N C Y  
o OPE!{ C I R C U I T   S T A N D  
o DISCHARGE  CHARACTERIZATION 
o CYCLE L I F E   O P E R A T I O N  
Figure 4-95 
TEST PRDGRAV 
o CONDITIOHIHG 
o CHARGE CHARACTERIZATION 
o OPEPI CIRCUIT STAND 
o CYCLE  EFFICIE:!CY 
o DISCHARGE CHAW\CTERIZATIOll  
o CYCLE L I F E  
- 
5 CELL DISCHARGE - 
CHARACTERIZATlON - 
:2 CELLS CYCLE L I F E  
I: ' iDITIOfIING 
22 CELLS+ OPEN CIRCUIT 
OPERATION 
- - - 
6 CELL- 
'DEGRADED ECFt:ARGE STAND 
CAPACITY 
5 CELL ELOCK 
l l lCLUDED 
ARTICLE 
If1 TEST 6 CELL- 110 TEST 
PROGRAM FLO'4 DIAGRAM 
Figure 4-96 
:IIFE L403 CELL  DESCRIPTION 
HEIGHT 405 m (15.9 i n .  
' I IOTH 144 m ( 7 . G  i n . )  
LE!IGTH 55 m ( 2 . 2  in.) 
l lE lGHT 6 .7  Kg (14.8 Lbs 
VOLUllE 2.0 L (0.53 g )  
ELECTROLYTE 
PES1STA:ICE / . I  /t? X- 
'FROI! 103% S.O.C.  TO  EO% 
DISCllARGE 0 25OC 
\ 
Figure 4-9 7 
3 82 
Figure 4-98 
3 83 
POCKET N I C K € L  
CADM I U M  PLATE, 
MANUFACTURING 
METAL SHEET 
~ \ \ y  OLD PERFORATION . METHOD 
30% MORE AREA U51NC 
NEW METHOD 
1 
Figure 4-99 
3 84 
CHARGE 
RATE 
( A I l P E R t S I  
TEllPERAIURE 
c o  
- 10 
25 
40 
-10 4n2 5  
- I n  
25 
40 
- 10 
40 25
S t L E C I E n  
CUTOFF 
VOLTAGE 
1 . 7 7  
I 63  
1 . 7 5  
1.5R 
1 . 6 2  
I .67 
1.76  
I .  70 
1.65 
1 . 7 7  
1.74 
1 . 7 0 '  
M l l l l r A C T U R L  
RlCnllllEtlOED 
CUTOFF 
I . R Z  
1.66 
1.88 
1.61 
I .  72 
I .  64 
1.89 
1.74 
1.66 
L94 
I. I8 
1.70 
ALL  DISCHARGES  COllDUCTED AT A C0NSTA:IT 10 PNPERE RPTE 
Figure 4- 100 
1.8 
I 1 ! .lO!C ' I 
1.7 
"" 
""t -"-L_7 
1.2 
1.1 
0 10 20 30 
TlHE HOURS 
COIISIAIlT  CURRENT- CllARGE CURVES AI 5 NIPERE 
RATE AS A FUI lCTlOI l  OF TEIIPEPATURE 
Figure 4- 1 02 
. . . . . . .  . . . . . .  - m .A. .:..""/-.I I 
: g , . . . . .  ! .. . /'. . . .  '., . . .  , I 1  
. . . . . . . .  , ...... - . .  -. ..... . .  I . . .  
I 
1 . 6 1  I 
.n 
2 
B . 1.4 
Y 
Y 
r 
2 
E 
1.3 
2 
Y " 
1.2 
1. I 
1.0 
0 2 4 6  8 10 I2 14 16 18 20 
. TIHE, IIOURS 
COIISTANT  CURREIIT  DISCHnRGE  CURVE  AT 10 AHPERE  RATE 
AS A FUl lCTlOl l  OF TEMPEMTURE TO 1.n VDC 
Figure 4- 103 
J 
5 10 15 71 25 
CH4RCE  CURREIIT.   AMPERES 
AllR E F F I C I E H C Y  iX k F U l l C T l O l l  OF CtlARGE  RATE AT 
SEVERAL  TEI IPERATUPES 
Figure 4- 1 04 
Figure 4- 1 05 
3 86 
DISCHARGE  CHARACTERIZATION AND CYCLE L I F E  TESTS 
o 5 CELL BLOCK  DESIGNATED FOR THE  DISCHARGE  CHARACTERIZATION  TEST  SUFFERED  AN 
UNEXPLAINED  ELECTROLYTE  LOSS  DURING 180 DAY OPEN CIRCUIT STORAGE PERIOD. 
o SUBSEQUENT CYCLING  AFTER  ESTORING  ELECTROLYTE TO SPECIFIED  LEVEL SHOWED 
A PERMANENT CAPACITY LOSS OF APPROXIMATELY 40%. 
o RESULTS  OF SUBSEQUENT CHARACTERIZATION AND CYCLE L I F E   T E S T I N G  ARE NOT 
CHARACTERISTIC OF NORMAL CELLS. 
Figure 4- 1 06 
w 
03 
03 
CELLS  DELIVERED  EXCELLENT  CAPACITY  AT  25OC AND 4OoC. 
HIGHER  CUTOFF  VOLTAGE  REQUIRED  AT  -1OOC  AT CHARGE RATES I N  EXCESS OF 5 AMPS. 
REASONABLE  AMPERE-HOUR E F F I C I E N C I E S  ARE  ACHIEVABLE  UNDER  PROPER CHARGE 
CONDIT IONS.  
C E L L S   E X H I B I T  GOOD CHARGE RETENTION  CHARhCTERISTICS  (APPROXIMATELY 3% LOSS 
PER MONTH AT  25OC) .  
ELECTROLYTE MANAGEMENT REQUIRED  TO  PREVENT  CAPACITY  LOSS. 
Figure 4- 107 


Pocket nickel cadmium cell and battery evaluation

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