Nickel-metal hydride battery with improved separator
A nickel-metal hydride electrochemical cell. The electrochemical cell includes separators electrical the positive electrode from the negative electrodes. The separators preferably have a hi-pot resistance greater than 400 volts, an ionic resistance less than 15 ohm-cm. The separator may additionally have an absorbency between 30% and 50% at 100 psi.
1 . A nickel-metal hydride electrochemical cell, comprising:
a positive electrode including a nickel-hydroxide active material;
a negative electrode including a hydrogen storage alloy active material;
a separator electrical insulating said positive electrode form said negative electrode, said separator having a hi-pot resistance greater than 400 volts, and an ionic resistance less than 15 ohm-cm; and
an alkaline electrolyte.
2 . The electrochemical cell of claim 1 , wherein said separator has an absorbency between 30% and 50% relative to said alkaline electrolyte at 100 psi.
3 . The electrochemical cell of claim 1 , wherein said separator has an absorbency between 35% and 48% relative to said alkaline electrolyte at 100 psi.
4 . The electrochemical cell of claim 1 , wherein said separator has an absorbency between 38% and 46% relative to said alkaline electrolyte at 100 psi.
5 . The electrochemical cell of claim 1 , wherein said separator has a hi-pot resistance greater than 500 volts.
6 . The electrochemical cell of claim 1 , wherein said separator has an ionic resistance less than 12 ohms-cm.
7 . The electrochemical cell of claim 1 , wherein said separator has an ionic resistance less than 10 ohm-cm.
8 . The electrochemical cell of claim 1 , wherein said alkaline electrolyte is an aqueous solution of an alkali metal hydroxide.
9 . The electrochemical cell of claim 8 , wherein said alkali metal hydroxide comprises potassium hydroxide, lithium hydroxide or sodium hydroxide.