NOVELTY - A super entropy change method of Ab4.7 non-stoichiometric ratio of hydrogen storage alloy involves preparing substrate hydrogen storage alloy by selecting and preparing materials, and putting prepared metal furnace material in an induction melting furnace crucible, followed by mixing rare earth metal comprising lanthanum, cerium, neodymium, and praseodymium. The prepared metal furnace material is put in an induction melting furnace crucible. The induction melting furnace crucible is vacuumized at a vacuum degree of 10-2, in the presence of argon gas, followed by performing lithiation process.    USE - Method for super entropy change of Ab4.7 non-stoichiometric ratio of hydrogen storage alloy.    ADVANTAGE - The method enables increasing low temperature discharge voltage of Ni-MH battery to 280mV at -36 degrees C.    DETAILED DESCRIPTION - A super entropy change method of Ab4.7 non-stoichiometric ratio of hydrogen storage alloy involves preparing substrate hydrogen storage alloy (MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05)) by selecting and preparing materials according to ratio of Ni(4.3)Al(0.3)Fe(0.05)Sn(0.05), where the Mm is mixed rare earth metal ingot, Ni is metal nickel plate, Al is metal aluminum block, Fe is metal iron rod and Sn is metal tin plate, and the metal purities are 99.95 wt.%, followed by mixing rare earth metal comprising lanthanum (61 wt.%), cerium (20 wt.%), neodymium (15 wt.%), praseodymium (4 wt.%). The prepared metal furnace material is put in an induction melting furnace crucible, where oxide skins of the mixing rare earth metal and the iron rod in the induction melting furnace crucible are removed by a induction melting furnace crucible. The induction melting furnace crucible is vacuumized at a vacuum degree of 10-2, in the presence of argon gas as a protective atmosphere, increasing electric power until all metal furnace materials are melted, smelting at 1450 plus minus 50 degrees C for 20 minutes, casting and discharging to obtain MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) substrate hydrogen storage alloy, where the entropy change metal Al and tin are added in an inducted and smelted way. Lithiation process is performed using MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) substrate hydrogen storage alloy by crushing the MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) substrate hydrogen storage alloy ingot into powder, sieving with 300-mesh sieve, bringing the metal lithium to the bottom of the crucible according to the weight ratio of hydrogen storage alloy powder and metal lithium of 100:0.5, scattering the substrate hydrogen storage alloy powder, covering the upper cover of the crucible, placing in a resistance furnace, pumping vacuum with mechanical pump until the vacuum degree reaches 10-2, filling argon gas as protective atmosphere, heating an electric furnace at 542 degrees C for 1.5 hours, preserving heat for 20 hours, and raising the temperature to 903 degrees C for 3 hours followed by preserving heat at 903 degrees C for 0.5 hour and cooling the furnace at room temperature to obtain the lithiated MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) hydrogen storage alloy powder aggregate, or the weighing hydrogen storage alloy powder and metal lithium at a ratio of 100:1, bringing the metal lithium to the bottom of the crucible according to the weight ratio of hydrogen storage alloy powder and metal lithium of 100:2, scattering the substrate hydrogen storage alloy powder, covering the upper cover of the crucible, placing in a resistance furnace, pumping vacuum with mechanical pump until the vacuum degree reaches 10-2, filling argon gas as protective atmosphere, heating the electric furnace at 260 degrees C for 1.2 hours, followed by preserving heat for 18 hours at 813 degrees C and cooling the furnace to room temperature to obtain the lithiated MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) hydrogen storage alloy powder aggregate. MH-Ni battery negative electrode plate is prepared for MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) hydrogen storage alloy powder agglomerates by crushing the obtained lithium of MmNi(4.3)Al(0.3)Fe(0.05)Sn(0.05) hydrogen storage alloy powder agglomerates into powder cake, adding 10 g of carboxymethyl cellulose (CMC) with concentration of 2 wt.%, 8 g of polyvinyl alcohol (PVA) with concentration of 0.8 wt.% and 7 g of crosslinked sodium polyacrylate with concentration of 1 wt.% to 100 g of the hydrogen-storage alloy powder cake, pouring the alloy powder cake and the three adheasives of CMC, PVA and sodium salt of poly(acrylic) acid to a mixer, stirring for 2 hours, standing for 2 hours, moving to a hopper of a battery pole plate machine, using nickel plating punching steel belt as the current collector, mechanically drawing by the battery pole plate machine, rolling, drying to obtain a battery negative electrode plate. The super entropy change reaction of the battery negative electrode plate in nickel metal hydride (Ni- MH) battery is performed by cutting battery negative electrode plate, removing burrs, electrochemically measuring the area specific capacity for self-assembling a square simulation battery of 100 ampere-hour, selecting the market sintering nickel anode as the square simulation battery of 100 ampere-hour, quantifying the number of the sintering nickel anodes according to the area specific capacity of the market sintering nickel anode and ensuring the number to satisfy 100 ampere-hour requirement, designing the battery negative electrode plate according to the total capacity of 170 ampere-hours, converting the area of the supposed negative electrode plate according to the measured electrochemical area specific capacity value and ensuring that the number of the negative electrode plates is more than one of the number of the sintering nickel anode plates, selecting polypropylene non-woven cloth type battery diaphragm, repeatedly stacking according to the sequence of one sintering nickel anode plate, one polypropylene non-woven cloth type battery diaphragm and one negative electrode plate, after all the positive and negative electrode plates are placed completely, welding respectively tabs of the positive and negative electrode plates together, at the same time welding an electrode outgoing wire on the positive and negative electrode tabs to form a square battery core, placing the battery core into a stainless steel battery shell, using the total number, 270 ampere hours of the design capacity of the positive and negative electrode as a base number, obtaining a weight value by multiplying the base number with 1.88 amp-hour coefficient, injecting potassium hydroxide aqueous solution to the stainless steel battery shell, sealing the battery shell, charging the simulation battery with the sealed shell for 13.5 hours with the speed of 10 ampere current, putting in the oven at temperature of 50 plus minus 1 degrees C, keeping constant temperature and carrying out heat preservation for 96 hours, all super entropy change reactions of AB4.7 non-stoichiometric ratio hydrogen storage alloy before molding of the AB4.7 non-stoichiometric hydrogen storage alloy battery are completed.