CN1300867C - Method for preparing sintered nickel anode for quickly charging type secondary battery - Google Patents

Abstract

The present invention belongs to the preparation technical field of a sintered nickel anode of an alkaline secondary cell. By enhancing the utilization rate of an active substance in an anode at high temperature, the problem of cell temperature rise caused by quick charge is solved. The present invention is characterized in that a nickel anode soaked in a Li, Y, Mg compound is irradiated by a <60> Co source; Li, Y, Mg in the micropores of the nickel anode are generated to memory effect and structure shaping, so the utilization rate of the active substance in the anode at high temperature is enhanced. The present invention has the advantages of simple manufacturing process and strong operability, can fully exert the functions of the Li in electrolyte, and is suitable for preparing the sintered nickel anode of a quick charge type alkaline secondary cell.

Description

The preparation method of sintered nickel anode for quickly charging type secondary battery

Technical field:

The invention belongs to the preparing technical field of alkaline secondary cell sintrered nickel anode.

Background technology:

The large-scale MH-Ni battery pack of using on the electric automobile, the battery heat radiation is restricted, quick charge is created in the seldom Joule heat on the every monocell, accumulate make the temperature of battery pack reach easily+60 ℃, the occasion that ambient temperature self is higher or the density of charging current is excessive or battery pack uses the later stage internal resistance to raise particularly, the temperature accumulation just is more prone to.And anode Ni (OH) ₂Active material among the/NiOOH promotes this temperature accumulation conversely along with the rising utilance of temperature reduces, and forms vicious circle.Under this background, improve the anode quick charge capability, one of prerequisite is to improve the utilance under the active material high temperature in the anode, and keeps certain overpotential for oxygen evolution and avoid separating out of oxygen as far as possible; Because it is more and more higher that field such as electric automobile requires for quickly charging battery performance etc., further improves sintered type Ni anode active material utilization in the time of+45 ℃～+ 60 ℃, be to improve one of problem that the quickly charging battery performance must solve.According to the experience accumulation that addresses this problem in decades, according to following preferred sequence, add column element: Li 〉=Cd＞Y 〉=Co 〉=Zn＞V 〉=Gd 〉=Ca 〉=Sr 〉=Mg 〉=Al down in the anode, can improve the quickly charging battery ability, improve overpotential for oxygen evolution, avoid battery to fill temperature rise soon, improve the active material utilization under ℃ high temperature of battery+60.But insoluble deep-seated problem is: 1. Li is easy to migration in the battery charging/discharging process, be difficult to be fixed on the sintering Ni anode or be concentrated in the anode region and play one's part to the full, can only join in the electrolyte its effect of performance at present, and adding proportion is subjected to the restriction of other factors in electrolyte; 2. the use of Cd is owing to the strictness of environmental consciousness raising and corresponding rules, and people more and more are unwilling to use, and the Cd compound that adds on the positive pole is moved on the negative pole obstruction negative pole charge/discharge work in the charge process; Though it is obvious that 3. the Y compound adds high temp effect, the excessive decline that causes room temperature and low temperature discharge capacity; 4. add Co in anode, must add a large amount of expensive Co guaranteeing enough characteristics, and redundance causes the decline of interdischarge interval voltage among a large amount of Co; 5. element additive effects such as Zn, V, Gd, Ca, Sr, Al, Mg can not show a candle to above-mentioned element, and based on booster action.Chinese patent discloses the patent that is entitled as " can stablize the alkaline battery that uses in wide temperature range " for No. 01116864.1, and this patent waits the generation that improves anodal high temperature charge performance and suppress oxygen by adding Y or other rare earth compound; Another Chinese patent discloses the patent that is entitled as " nickel positive electrode plate and the manufacture method thereof that are used for alkaline battery " for No. 00801209.1, and this patent is added the high temperature utilance that Gd and Y improve active material in the sintering Ni anode in sintering Ni anode.Make the similar approach that is used for improving non-sintering Ni anode high-temperature behavior No. 95115816.3 and No. 97114882.1 detailed announcement be arranged also jointly with Mg, Al, In salt and the co-precipitation of Co salt or Y, Co at Chinese patent.But the common defects of above-mentioned patent is: 1. the effect of Li is not fully played; 2. complex process, poor operability.

Summary of the invention:

The object of the present invention is to provide a kind of technology simple, workable and give full play to the preparation method of fast stamp sintrered nickel anode of the effect of Li in the electrolyte.

Realize the present invention institute based on cardinal principle be: based on the compound of saturated Li, the compound with a spot of rich yttrium mixed rare earth MY and Mg is auxilliary simultaneously, be filled in the micropore of commercially available ordinary sinter nickel anode, be what lead in order to gamma-radiation under the room temperature ⁶⁰Co irradiation bomb irradiation doses, make Li in the micropore of nickel anode etc. produce memory effect and structure typing, afterwards in the battery charging/discharging use, be easy to the Li of migration and Mg etc., even migration is in electrolyte, because the effect of memory effect, in the quick charge process, Li etc. revert in the stereotyped structure in the micropore of original nickel anode easily, are beneficial to Li etc. and give full play to the effect that improves active material utilance under high-temperature condition in the nickel anode.

The present invention takes following technical scheme to realize: with commercially available purity is 99.5% rich yttrium mixed rare earth oxide M Y, 96% the special-purpose LiOH of battery, 99.5% Mg (NO ₃) ₂6H ₂O, 99% HNO ₃, 99% KOH and the commercially available Co of containing type and contain Zn type sintered type Ni (OH) ₂/ NiOOH nickel anode is raw material; The percentage by weight of wherein rich yttrium mixed rare earth MY middle rare earth element consists of: Y is 88.2%, and Er is 6.9%, and Ho is 1.4%, and Yb is 1.2%, and other rare earth summation such as Gd is 2.3%, with nitric acid it is mixed with the MY (NO of 1mol/L ₃) ₃Standby.Mg (NO ₃) ₂6H ₂O be mixed with 0.8mol/L and with the MY (NO of 1mol/L ₃) ₃Equal-volume mixes, and is mixed with and contains MY ³⁺And Mg ²⁺The MY-Mg mixed liquor standby; Sintering Ni anode strip boils wetting, sinter layer cutting-up, cuts out out long 5cm through distilled water, the rectangular electrodes sheet of wide 1cm, it on Ni sheet in the impulse spot welder welding as lead-in wire; This electrode slice is put into+65 ℃ ± 5 ℃ saturated LiOH solution in hot dipping 1～2 hour, taking-up washes the surface crystallization thing with distilled water, and then be transferred in the MY-Mg mixed liquor soaking at room temperature 24 hours, from this mixed liquor, take out, be put back in original saturated LiOH solution, after 1～6 hour this electrode slice be put into together with the saturated LiOH solution that soaks it and the container of splendid attire thereof in soaking at room temperature ⁶⁰The assigned address of Co irradiation bomb is lifted out from irradiation well ⁶⁰The Co irradiation bomb, irradiation 8～40 Megarads are taken out this electrode slice with distilled water and are cleaned, and oven dry obtains required sintrered nickel anode.

Clamp this positive plate with 6 Φ 10mm garden negative plates, each 3 garden shape negative plate of positive plate both sides and connect with the nickel sheet, separate with nylon diaphragm between the positive and negative electrode, be soaked in the simulated battery that composition is just limiting in the 6mol/L KOH solution, this negative electrode active material is selected AB ₅The class hydrogen-storage alloy powder, this powder mixes, colds pressing and obtain by mass ratio with carbonyl Ni powder at 1: 5, and the discharge capacity of this negative plate is designed to 150% of blank positive electrode capacity.Test this simulated battery performance with the DC-5 cell tester, ultra low temperature freezer and water bath with thermostatic control are respectively applied for low temperature and high temperature test, the constant temperature of high and low temperature test is defined as: be charged to anodal rated capacity, cryogenic freezing or heat discharge into the cut-ff voltage of regulation after 8 hours.

Preparation method of the present invention has remarkable advantage, and technological process is short, and preparation condition is easy to control, and simple to operate, cost is low, has reached goal of the invention.

Embodiment:

Embodiment 1:

Getting the 500ml molar concentration is the MY (NO of 1mol/L ₃) ₃Mg (NO with the 0.8mol/L of equal volume ₃) ₂6H ₂O is mixed with and contains MY ³⁺And Mg ²⁺The MY-Mg mixed liquor standby; Containing Co type sintering Ni anode strip boils wetting, sinter layer cutting-up, cuts out out long 5cm through distilled water, the rectangular electrodes sheet of wide 1cm, go up the Ni sheet as lead-in wire with impulse spot welder welding on it, this electrode slice is put into+65 ℃ ± 5 ℃ saturated LiOH solution in hot dipping, hot dipping time t ₁=1 hour, take out and to wash the surface crystallization thing, and then be transferred in the MY-Mg mixed liquor soaking at room temperature 24 hours with distilled water, from this mixed liquor, take out, be put back in original saturated LiOH solution, at soaking at room temperature t ₂After=6 hours with this electrode slice together with the saturated LiOH solution that soaks it, and the container of splendid attire is put into together ⁶⁰The assigned address of Co irradiation bomb is used ⁶⁰Co irradiation bomb irradiation, irradiation metering R=8 Megarad is taken out this electrode slice with distilled water and is cleaned oven dry; Clamp this positive plate with 6 Φ 10mm garden negative plates, each 3 garden shape negative plate of positive plate both sides and connect with the nickel sheet, separate with nylon diaphragm between the positive and negative electrode, be soaked in the simulated battery that composition is just limiting in the 6mol/LKOH solution, this negative electrode active material is selected AB ₅The class hydrogen-storage alloy powder, this powder mixes, colds pressing and obtain by mass ratio with carbonyl Ni powder at 1: 5, and the discharge capacity of this negative plate is designed to 150% of blank positive electrode capacity.Test this simulated battery performance with the DC-5 cell tester, ultra low temperature freezer and water bath with thermostatic control are respectively applied for low temperature and high temperature test; The anodal charge condition of high and low temperature test is: Ic=83mA/cm ³, being charged to anodal rated capacity, cryogenic freezing or heat discharge into cut-ff voltage after 8 hours be 0.8V.Cycling life test is carried out at+19 ℃ ± 4 ℃, sets Ic=I _d=410mA/cm ³, the anodal room temperature heap(ed) capacity of charging tolerance limit=98%, discharge cut-off voltage 0.8V.Charged experiment is carried out chargeability Q under+20 ℃ ± 4 ℃ _HAccording to formula Q _H=C _b/ 0.5 (C _a+ C _c) calculating, wherein C _aBe the last discharge capacity before charged, C _bBe the discharge capacity first of starting shooting after charged, C _cDischarge capacity when starting shooting for the second time normally charge and discharge for charged back, the charged time is 120 hours.The multiplying power discharging property test is carried out under+18 ℃ ± 4 ℃, with Ic=200mA/cm ³Be charged to heap(ed) capacity, discharge cut-off voltage is 0.6V.The wide warm area discharge performance that obtains, cycle life, multiplying power discharging property, charging performance are listed in table 1～3 respectively

Embodiment 2:

Get t ₁=2 hours; t ₂=1 hour; The R=40 Megarad; All the other are with embodiment 1.Institute's obtained performance index is listed in table 1～3 respectively.

Embodiment 3:

Get t ₁=1.4 hours; t ₂=4 hours; The R=20 Megarad; All the other are with embodiment 1.Institute's obtained performance index is listed in table 1～3 respectively.

Embodiment 4:

With containing Zn type sintered type Ni (OH) ₂/ NiOOH nickel anode replaces containing Co type nickel anode, gets t ₁=1.5 hours; t ₂=3 hours; The R=24 Megarad; All the other are with embodiment 1.Institute's obtained performance index is listed in table 1～3 respectively.

Embodiment 5:

Get t ₁=1.8 hours; t ₂=4.4 hours; The R=18 Megarad; All the other are with embodiment 4.Institute's obtained performance index is listed in table 1～3 respectively.

Embodiment 6:

Get t ₁=1.2 hours; t ₂=2.6 hours; The R=15 Megarad; All the other are with embodiment 4.Institute's obtained performance index is listed in table 1～3 respectively.

Table 1: at I _c=I _d=83mA/cm ³The time, the discharge capacity mAh/cm of sintering Ni anode under different temperatures ³

Table 2: at room temperature and I _d=83mA/cm ³The time, sintering Ni anode is in different I _cUnder discharge capacity .mAh/cm ³

Table 3: sintering Ni anode is cycle life, multiplying power discharging and charging performance at room temperature

Sample	Cycle life performance mAh/cm 3		Multiplying power discharging property mAh/cm 3		Charging performance
						300 times	450 times	I d＝1640mA/cm 3	I d＝2460mA/cm 3	％
	Contain the Co blank	389	369	378	242						82.1
Contain the Zn blank						381	367	374	243	80.2
	Embodiment 1	390	381	382	264						82.5
Embodiment 2						391	383	387	270	78.4
	Embodiment 3	389	382	381	268						85.3
Embodiment 4						384	381	378	261	83.4
	Embodiment 5	380	374	379	254						67.4
Embodiment 6						381	375	371	266	77.5

Claims (1)

1. A method for preparing a sintered nickel anode for a fast-charging alkaline secondary battery, characterized in that: the yttrium-rich mixed rare earth MY is prepared into 1mol/L MY(NO ₃ ) ₃ with nitric acid, wherein the yttrium-rich mixed rare earth The weight percent composition of rare earth elements in rare earth MY is: Y is 88.2%, Er is 6.9%, Ho is 1.4%, Yb is 1.2%, and the sum of Gd and other rare earth elements is 2.3%; Mg(NO ₃ ) ₂ ·6H ₂ O Prepared to 0.8mol/L and mixed with 1mol/L MY(NO ₃ ) ₃ in equal volume to prepare a MY-Mg mixture containing MY ³⁺ and Mg ²⁺ ; the sintered Ni anode was boiled with distilled water to wet and sinter Cut and cut out a rectangular electrode sheet with a length of 5 cm and a width of 1 cm; use a pulse spot welder to weld a Ni sheet on it as a lead wire; put the electrode sheet into a saturated LiOH solution at +65°C±5°C and hot-dip for 1 ~2 hours, take it out and wash off the surface crystals with distilled water, and then transfer it to the MY-Mg mixture and soak it at room temperature for 24 hours, take it out from the mixture, put it back into the original saturated LiOH solution, and leave it at room temperature After soaking for 1 to 6 hours, put the electrode piece together with the soaked saturated LiOH solution and its containing container at the designated position of the ⁶⁰ Co radiation source, lift ^{the 60} Co radiation source from the irradiation well, and irradiate for 8 to 8 hours. 40 Mrad, and then take out the electrode sheet, wash it with distilled water, and dry it to obtain the required sintered nickel anode.