With some difficulty, I located this: https://www.google.com/patents/WO1990010935A1
This is text only. A facsimile with the drawing and whatnot is here: http://worldwide.espacenet.com/publicationDetails/originalDocument;jsessionid=1390745C5115A135F05177764A1A7766.espacenet_levelx_prod_3?CC=WO&NR=9010935A1&KC=A1&FT=D&ND=&date=19900920&DB=&&locale=en_EP Fig. III-7E on p. 16 is titled "Specific Excess Energy, Megajoules." It shows the cell produced ~18 MJ. That was a lot for the early days. - Jed
