U.S. patents filed on the topic of nickel/metal hydride (Ni/MH) batteries have been reviewed, starting from active materials, to electrode fabrication, cell assembly, multi-cell construction, system integration, application, and finally recovering and recycling. In each category, a general description about the principle and direction of development is given. Both the metal hydride (MH) alloy and nickel hydroxide as active materials in negative and positive electrodes, respectively, are reviewed extensively. Both thermal and battery management systems (BMSs) are also discussed.

https://www.mdpi.com/2313-0105/2/2/10/pdf

Reviews on the U.S. Patents Regarding Nickel/Metal Hydride Batteries

Nickel-metal hydride batteries and electrodes are capable of increased power output and recharge rates. The electrodes and batteries produced therefrom exhibit increased internal conductance. The positive and negative electrodes may be formed by pressing powdered metal hydride active materials into the porous metal substrates. The substrates are formed from copper, copper-plated nickel, or a copper-nickel alloy, and additionally may be plated with a material which is electrically conductive and resistant to corrosion in the battery environment, such as nickel. The positive electrodes can also include high-conductivity regions on the substrate. These regions have a higher electrical conductivity than the rest of the substrate. Each electrode (1) may include a tab (2), which may be made of nickel, or nickel-plated copper.

High power nickel-metal hydride batteries and high power alloys/electrodes for use therein

A modified Ti—V—Zr—Ni—Mn—Cr electrochemical hydrogen storage alloy which has at least one of the following characteristics: 1) an increased charge/discharge rate capability over that the base Ti—V—Zr—Ni—Mn—Cr electrochemical hydrogen storage alloy; 2) a formation cycling requirement which is reduced to one tenth that of the base Ti—V—Zr—Ni—Mn—Cr electrochemical hydrogen storage alloy; or 3) an oxide surface layer having a higher electrochemical hydrogen storage catalytic activity than the base Ti—V—Zr—Ni—Mn—Cr electrochemical hydrogen storage alloy

Modified electrochemical hydrogen storage alloy having increased capacity, rate capability and catalytic activity

An improved metal hydride hydrogen storage alloy electrochemical cell (10) includes a positive electrode (20) and a negative electrode (30) having disposed therebetween, a polymer electrolyte (40). The polymer electrolyte (40) comprises a polymer support structure fabricated of, for example, polyvinyl alcohol or polyvinyl acetate, and having dispersed therein an electrolyte active species such as, for example, KOH. The improved electrolyte for a metal hydride hydrogen storage alloy cell provides a battery cell free from electrolyte leakage, and having ionic conductivities which allow for an efficient use of the metal hydride electrodes.

Metal hydride electrochemical cell having a polymer electrolyte

The present invention discloses a method to make a high rate, fast oxygen recombination and long life rechargeable metal oxide-hydride batteries, and in particular, rechargeable nickel-hydride batteries. The battery, according to this invention, is composed of a high rate, fast oxygen recombination and long life hydrogen storage electrode as a negative electrode. The hydrogen storage material is prepared to have a thin oxide top surface layer and a metal-rich subsurface layer, especially a nickel-rich subsurface layer. In the microstructure, it is preferable that it consists of a nickel-rich composition in one type of the grains and/or in grain boundaries. The hydride electrode made has an electrochemical capacity from 1.15 to 2.40 AH/cc. Before or after cell assembly, sealing, and/or using, the hydrogen storage electrode is chemically or electrochemically precharged to a state having a half-cell open circuit potential of -0.790 to -0.905 V vs. Hg/HgO reference electrode, and to have an initial charging potential of -0.830 to -1.005 V vs. Hg/HgO reference electrode at a current density of 100 mA/g of active material. The hydrogen storage electrode is composed of at least a hydrogen storage material (alloy), and/or its hydride thereof. The hydrogen storage material consists of nickel and at least five other elements as modifiers; where the atomic mole percent of nickel in the material is greater than 18 at. % but less than 80 at. %, preferably greater than 30 at. % but less than 65 at. %. The modifiers include: (a) at least two hydride formers selected from the group of Ti, Zr, Hf, V, Nb, Ta, Y, Sc, Mg, Ca, Pd, and rare earth metals; (b) at least one de-stabilizing agent selected from the group of Cr, Mn, Fe, Co, Cu, Zn, Mo, Sn, C, B, Sb, Si, Bi Ge, Ga, N, O, and Sn; (c) at least one element selected from the group of corrosion resisting agents selected from the group consisting of Cr, Co, W, Mo, Nb, Hf, and Ta; and (d) at least one element selected from the groups of oxygen getters, catalysts, or the combinations. The oxygen getter is selected from the group consisting of alkali metals, Ca, Al, Sr, Ba, Zr, Hf, Ti, rare earth metals, P, and S. The catalyst is selected from the group consisting Cu, Mn, W, Mo, Pd, Co and O.

Method for making high charging efficiency and fast oxygen recombination rechargeable hydride batteries

An electrochemical hydrogen storage alloy having decreased hydrogen overpressure as well as other desirable operational parameters, comprising on an atomic percent basis: 14 to 22 percent vanadium; 28 to 39 percent nickel; 7 to 15 percent titanium; 15 to 34 percent zirconium; and at least one member selected from the group consisting of 0.001 to 7 percent chromium, 0.001 to 7 percent cobalt, 0.001 to 7 percent iron, 0.001 to 3.6 percent manganese, and 0.001 to 2.7 percent aluminum, wherein the atomic ratio of the vanadium to zirconium is in the range of 1:2.26 to 1:0.68. An electrochemical hydrogen storage alloy having a reduced self-discharge rate comprising an alloy having a heterogeneous, disordered microstructure resulting from changes in the mutual solubility of the elements of the alloy, wherein hydrogen in a particular phase is not easily discharged either though low surface area, or an oxide of limited porosity or catalytic property.

Masayuki Hirota

Papers

Electrode alloy having decreased hydrogen overpressure and/or low self-discharge