Stabilized nickel-zinc battery

Claim 2

A sealed alkaline nickel zinc cell comprising: A. a nickel-nickel hydroxide cathode; B. a zinc-zinc oxide anode comprising: (1) a corrosion inhibitor selected from the group consisting of (a) from 0.5 to 10.0 weight percent of PbO, (b) from 0.5 to 10.0 weight percent of SnO 2 , (c) from more than zero to 1.0 weight percent of Tl 2 O 3 , (d) from more than zero to 1.0 weight percent of In(OH) 3 , and (e) mixtures thereof, provided that the total weight percent of corrosion inhibitor does not exceed 10.0 weight percent and the weight percent of Tl 2 O 3 plus In(OH) 3 does not exceed 1.0 weight percent; (2) from 0.5 to 10.0 weight percent of a slight corrosion accelerator selected from the group consisting of (a) CdO, (b) Bi 2 O 3 , (c) Ga 2 O 3 , and (d) mixtures thereof, provided that the total weight percent of slight corrosion accelerators does not exceed 10.0 weight percent; and (3) zinc active material; wherein the weight percentages are based on the total weight of the corrosion inhibitor, slight corrosion accelerator, and zinc active material when the anode is in the uncharged state; C. a mass transport separator; D. an alkaline electrolyte; and E. means for charging the cell by interrupted current wherein the charge frequency is from more than zero to 16 Hertz and the rest interval between charge pulses is a minimum of 60 milliseconds.

Claim 3

The cell of claim 1 wherein the corrosion inhibitor in the zinc anode comprises from 1.0 to 5.0 weight percent of a member selected from the group consisting of PbO, SnO 2 , and mixtures thereof.

Claim 4

The cell of claim 1 wherein the corrosion inhibitor comprises from 0.1 to 0.5 weight percent of a member selected from the group consisting of Tl 2 O 3 , In(OH) 3 , and mixtures thereof.

Claim 5

The cell of claim 1 wherein the corrosion inhibitor in the zinc anode comprises from 0.5 to 10.0 weight percent of PbO.

Claim 6

The cell of claim 4 wherein the corrosion inhibitor in the anode comprises from 1.0 to 5.0 weight percent of PbO.

Claim 7

The cell of claim 1 wherein the slight corrosion accelerator in the zinc anode comprises from 1.0 to 5.0 weight percent.

Claim 8

The cell of claim 1 wherein the slight corrosion accelerator in the zinc anode comprises from 0.5 to 10.0 weight percent of CdO.

Claim 9

The cell of claim 7 wherein the weight percent of CdO is from 1.0 to 5.0.

Claim 10

The cell of claim 1 wherein the charge frequency is from 5 to 10 Hertz.

Claim 11

The cell of claim 1 wherein the rest interval between charge pulses is a minimum of 70 milliseconds.

Claim 12

The cell of claim 10 wherein the charge frequency is from 5 to 10 Hertz.

Claim 13

The cell of claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 wherein the mass-transport separator comprises: (1) a barrier layer comprising a microporous polyolefin membrane which is coated on one side with a mixture of (a) fine particles of a low hydrogen overpotential material having a hydrogen overpotential in alkaline solution lower than that of zinc; and (b) a cationic electrolyte absorbent polymeric resin, wherein the weight ratio of low hydrogen overpotential material to resin is from about 2:1 to about 5:1; (2) a cationic electrolyte absorbent semipermeable membrane of a hydroxyl containing polymer placed in contact with the barrier layer and located between the barrier layer and the anode; and (3) two protective layers comprising microporous polyolefin membranes; wherein the barrier layer and the cationic electrolyte absorbent semipermeable membrane are sandwiched between and in contact with the two protective layers.

Claim 14

The cell of claim 12 wherein the ratio of low hydrogen overpotential material to cellulose acetate is from 2:1 to 3:1.

Claim 15

The cell of claim 12 wherein the low hydrogen overpotential material is nickel.

Claim 16

The cell of claim 12 wherein the hydroxyl containing polymer is cellulose.

Claim 17

A sealed cell according to claim 12 which further includes a pressure cutoff switch which stops the charging of the cell when the internal pressure reaches a selected value in the range of from 5.0 to 8.0 psig.

Claim 18

A sealed cell according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11 which further includes a pressure cutoff switch which stops the charging of the cell when the internal pressure reaches a selected value in the range of from 5.0 to 8.0 psig.

Claim 19

The cell of claim 12 wherein the cationic electrolyte absorbent resin is cellulose acetate.

Claim 20

A sealed cell according to claim 18 which further includes a pressure cutoff switch which stops the charging of the cell when the internal pressure reaches a selected value in the range of from 5.0 to 8.0 psig.

Claim 21

A nickel-zinc power system comprising: I. two or more sealed alkaline nickel-zinc cells each comprising A. a nickel-nickel hydroxide cathode; B. a zinc-zinc oxide anode comprising: (1) a corrosion inhibitor selected from the group consisting of (a) from 0.5 to 10.0 weight percent of PbO, (b) from 0.5 to 10.0 weight percent of SnO 2 , (c) from more than zero to 1.0 weight percent of Tl 2 O 3 , (d) from more than zero to 1.0 weight percent of In(OH) 3 , and (e) mixtures thereof, provided that the total weight percent of corrosion inhibitor does not exceed 10.0 weight percent and the weight percent of Tl 2 O 3 plus In(OH) 3 does not exceed 1.0 weight percent; (2) from 0.5 to 10.0 weight percent of a slight corrosion accelerator selected from the group consisting of (a) CdO, (b) Bi 2 O 3 , (c) Ga 2 O 3 , and (d) mixtures thereof, provided that the total weight percent of slight corrosion accelerators does not exceed 10.0 weight percent; and (3) zinc-active material; wherein the weight percentages are based on the total weight of the corrosion inhibitor, slight corrosion accelerator, and zinc active material when the anode is in the uncharged state; C. a mass transport separator comprising (1) a barrier layer comprising a microporous polyolefin membrane which is coated on one side with a mixture of (a) fine particles of a low hydrogen overpotential material having a hydrogen overpotential in alkaline solution lower than that of zinc; and (b) a cationic electrolyte absorbent polymeric resin, wherein the weight ratio of low hydrogen overpotential material to resin is from about 2:1 to about 5:1; (2) a cationic electrolyte absorbent semipermeable membrane of a hydroxyl cotaining polymer place in contact with the barrier layer between the barrier layer and the anode; and (3) two protective layers comprising microporous polyolefin membranes; wherein the barrier layer and the cationic electrolyte absorbent semipermeable membrane are sandwiched between and in contact with the two protective layers; D. an alkaline electrolyte; and E. a pressure cutoff switch which stops the charging of the cell when the internal pressure reaches a preselected value in the range of from 5.0 to 8.0 psig and is attached to each cell and series connected to the charge in a separate circuit; and II. means for charging the cells by interrupted current wherein the charge frequency is from about 1 to less than 16 Hertz and the rest interval between charge pulses is a minimum of 60 milliseconds; the sealed nickel-zinc cell being connected in series to the charging means so that when the internal gas pressure of any cell reaches the preselected value in the range of 5.0 to 8.0 psig, all of the cells stop charging.

Claim 22

A nickel-zinc power system comprising: I. two or more sealed alkaline nickel-zinc cells each comprising A. a nickel-nickel hydroxide cathode; B. a zinc-zinc oxide anode comprising: (1) a corrosion inhibitor selected from the group consisting of (a) from 0.5 to 10.0 weight percent of PbO, (b) from 0.5 to 10.0 weight percent of SnO 2 , (c) from more than zero to 1.0 weight percent of Tl 2 O 3 , (d) from more than zero to 1.0 weight percent of In(OH) 3 , and (e) mixtures thereof, provided that the total weight percent of corrosion inhibitor does not exceed 10.0 weight percent and the weight percent of Tl 2 O 3 plus In(OH) 3 does not exceed 1.0 weight percent; (2) from 0.5 to 10.0 weight percent of a slight corrosion accelerator selected from the group consisting of (a) CdO, (b) Bi 2 O 3 , (c) Ga 2 O 3 , and (d) mixtures thereof, provided that the total weight percent of slight corrosion accelerators does not exceed 10.0 weight percent; and (3) zinc-active material; wherein the weight percentages are based on the total weight of the corrosion inhibitor, slight corrosion accelerator, and zinc active material when the anode is in the uncharged state; C. a mass transport separator comprising (1) a barrier layer comprising a microporous polyolefin membrane which is coated on one side with a mixture of (a) fine particles of a low hydrogen overpotential material having a hydrogen overpotential in alkaline solution lower than that of zinc; and (b) a cationic electrolyte absorbent polymeric resin, wherein the weight ratio of low hydrogen overpotential material to resin is from about 2:1 to about 5:1; (2) a cationic electrolyte absorbent semipermeable membrane of a hydroxyl cotaining polymer place in contact with the barrier layer between the barrier layer and the anode; and (3) two protective layers comprising microporous polyolefin membranes; wherein the barrier layer and the cationic electrolyte absorbent semipermeable membrane are sandwiched between and in contact with the two protective layers; D. an alkaline electrolyte; and E. a pressure cutoff switch which stops the charging of the cell when the internal pressure reaches a preselected value in the range of from 5.0 to 8.0 psig and is attached to each cell and series connected to the charge in a separate circuit; and II. means for charging the cells by interrupted current wherein the charge frequency is from about 1 to less than 16 Hertz and the rest interval between charge pulses is a minimum of 60 milliseconds; the sealed nickel-zinc cell being connected in series to the charging means so that when the internal gas pressure of any cell reaches the preselected value in the range of 5.0 to 8.0 psig, all of the cells stop charging.

Claim 23

The power system of claim 20 wherein the corrosion inhibitor in the zinc anode comprises from 1.0 to 5.0 weight percent of a member selected from the group consisting of PbO, SnO 2 , and mixtures thereof.

Claim 24

The power system of claim 20 wherein the corrosion inhibitor in the zinc anode comprises from 0.1 to 0.5 weight percent of a member selected from the group consisting of Tl 2 O 3 , In(OH) 3 , and mixtures thereof.

Claim 25

The power system of claim 20 wherein the corrosion inhibitor in the zinc anode comprises from 0.5 to 10 weight percent of PbO.

Claim 26

The power system of claim 23 wherein the corrosion inhibitor in the zinc anode comprises from 1.0 to 5.0 weight percent of PbO.

Claim 27

The power system of claim 20 wherein the slight corrosion accelerator in zinc anode comprises from 0.5 to 10.0 weight percent of CdO.

Claim 28

The power system of claim 25 wherein the weight percent of CdO is from 1.0 to 5.0.

Claim 29

The power system of claim 20 wherein the charge frequency is from 5 to 10 Hertz.

Claim 30

The power system of claim 20 wherein the rest interval between charge pulses in a minimum of 70 milliseconds.

Claim 31

The power system of claim 28 wherein the charge frequency is from 5 to 10 Hertz.

Claim 32

The power system of claim 20 wherein the ratio of low hydrogen overpotential material to cellulose acetate is from 2:1 to 3:1.

Claim 33

The power system of claim 20 wherein the low hydrogen overpotential material is nickel.

Claim 34

The power system of claim 20 wherein the hydroxyl containing polymer is cellulose.

Claim 35

The power system of claim 20 wherein the cationic electrolyte absorbent resin is cellulose acetate.