A nickel-hydrogen battery and a preparation method thereof

Abstract

The application discloses a nickel-hydrogen battery and a preparation method thereof. The nickel-hydrogen battery comprises a positive electrode sheet, a negative electrode sheet and an electrolyte. The positive electrode sheet comprises a positive electrode surface layer material and a positive electrode base material, and the negative electrode sheet comprises a negative electrode surface layer material and a negative electrode base material. The positive electrode surface layer material comprises: 80-98 parts by weight of cobalt-coated spherical nickel hydroxide; and 1-8 parts by weight of a transition metal oxide; wherein the transition metal oxide is selected from one or more of a group III B metal oxide or a group IV B metal oxide. The negative electrode surface layer material comprises: 80-90 parts by weight of La-Y-Ni hydrogen storage alloy; 0.1-0.5 parts by weight of a conductive agent; and 4-6 parts by weight of yttrium oxide. The electrolyte comprises: 8-20 parts by weight of KOH; 13-25 parts by weight of NaOH; 0.5-6 parts by weight of LiOH; and 50-80 parts by weight of water. The nickel-hydrogen battery has a long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to a nickel-hydrogen battery and a preparation method thereof. BACKGROUND

[0002] The nickel-hydrogen battery has the advantages of no memory effect, strong overcharge and discharge resistance and good safety. At present, the nickel-hydrogen battery has been widely used in electronic devices such as mobile communication and notebook computer, and some large-capacity nickel-hydrogen batteries are applied to gasoline / electric hybrid vehicles.

[0003] CN104362390A discloses a nickel-hydrogen battery, which comprises a steel shell, a combined cover cap is arranged at the upper opening of the steel shell through a sealing ring, and a positive plate and a negative plate separated by a diaphragm and an electrolyte are arranged in the steel shell. The positive electrode substrate is foamed nickel. The positive electrode surface material comprises cobalt-coated spherical nickel hydroxide, cobalt oxide or cobalt hydroxide, two or three of yttrium oxide, lanthanum oxide, zirconium dioxide, titanium dioxide and ytterbium oxide, PTFE emulsion and CMC powder. The negative electrode substrate is a nickel-plated perforated steel strip. The negative electrode surface material is AB5 or AB3 type hydrogen storage alloy powder, nickel powder, graphite, CMC solution and SBR emulsion. The electrolyte is composed of 1-5 parts by weight of LiOH·H2O, 20-25 parts by weight of NaOH, 1-5 parts by weight of KOH and 60-70 parts by weight of deionized water. The service life of the nickel-hydrogen battery is short.

[0004] CN102956893A discloses a nickel-hydrogen battery, which comprises a positive electrode, a negative electrode and an electrolyte. The active material of the positive electrode comprises nickel hydroxide, cobalt-coated spherical nickel hydroxide and yttrium oxide. The negative electrode substrate is a copper mesh. The active material of the negative electrode is hydrogen storage alloy powder. The electrolyte is potassium hydroxide, lithium hydroxide, potassium bromide, sodium hydroxide and barium hydroxide. The service life of the nickel-hydrogen battery is short.

[0005] CN102324578A discloses a nickel-hydrogen battery. The positive electrode material is composed of a positive electrode active material, an additive and a binder. The positive electrode active material is cobalt-coated sub-nickel, the additive is an oxide or hydroxide of calcium and yttrium elements, and the binder is polytetrafluoroethylene. The negative electrode active material is alloy powder. This scheme is not suitable for improving the service life of a hydrogen storage battery with La-Y-Ni system hydrogen storage alloy as a negative electrode component. SUMMARY

[0006] Therefore, one object of the present application is to provide a nickel-hydrogen battery. The service life of the nickel-hydrogen battery is long. Further, the discharge capacity of the nickel-hydrogen battery is high.

[0007] Another object of the present application is to provide a preparation method of a nickel-hydrogen battery. The preparation method can improve the service life of the nickel-hydrogen battery.

[0008] The technical purposes are achieved by the following technical solutions.

[0009] In one aspect, the application provides a nickel-hydrogen battery, comprising a positive electrode sheet, a negative electrode sheet and an electrolyte; the positive electrode sheet comprises a positive electrode surface layer material and a positive electrode base material, and the negative electrode sheet comprises a negative electrode surface layer material and a negative electrode base material;

[0010] The positive electrode surface layer material comprises:

[0011] Cobalt-coated spherical nickel hydroxide 80-98 parts by weight; and

[0012] Transition metal oxide 1-8 parts by weight;

[0013] The transition metal oxide is selected from one or more of a group III B metal oxide or a group IV B metal oxide;

[0014] The negative electrode surface layer material comprises:

[0015] La-Y-Ni hydrogen storage alloy 80-90 parts by weight;

[0016] Conductive agent 0.1-0.5 parts by weight; and

[0017] Yttrium oxide 4-6 parts by weight;

[0018] The conductive agent is selected from one or more of carbon black, acetylene black or graphene;

[0019] The electrolyte comprises:

[0020] KOH 8-20 parts by weight;

[0021] NaOH 13-25 parts by weight;

[0022] LiOH 0.5-6 parts by weight; and

[0023] Water 50-80 parts by weight.

[0024] According to the nickel-hydrogen battery of the application, preferably, the transition metal oxide is selected from one or more of zirconium oxide or yttrium oxide.

[0025] According to the nickel-hydrogen battery of the application, preferably, the length of the positive electrode sheet is 70-100 mm, the width is 30-50 mm, and the thickness is 0.3-0.8 mm;

[0026] The length of the negative electrode sheet is 105-150 mm, the width is 30-50 mm, and the thickness is 0.05-0.4 mm.

[0027] According to the nickel-hydrogen battery of the application, preferably, the La-Y-Ni hydrogen storage alloy has the following composition:

[0028] RE x Y y Ni d Mn a Al b M c

[0029] RE is selected from one or more of La, Ce, Sm, and Gd, and must contain La; M is selected from one or more of Co, Fe, and Cu.

[0030] Where 0.2≤x≤0.8, x+y=2, 0.1≤a≤0.4, 0.1≤b≤0.4, 0.1≤c≤0.5, 6.7≤a+b+c+d≤7.2; x, y, a, b, c, and d represent the molar fractions of each element.

[0031] In the nickel-metal hydride battery according to the present invention, preferably, the positive electrode substrate is nickel foam and the negative electrode substrate is nickel-plated steel strip.

[0032] According to the nickel-metal hydride battery of the present invention, preferably, the positive electrode surface material further includes a first binder, wherein the first binder is selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene;

[0033] The negative electrode surface material further includes a second binder, which is selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene.

[0034] According to the nickel-metal hydride battery of the present invention, preferably, the nickel-metal hydride battery further includes a separator and a casing;

[0035] The separator is located between the positive electrode and the negative electrode, and the separator is a sulfonated separator or a grafted separator;

[0036] The positive electrode, negative electrode, separator, and electrolyte are located inside the outer casing.

[0037] On the other hand, the present invention provides a method for preparing the above-mentioned nickel-metal hydride battery, comprising the following steps:

[0038] (1) Coating the positive electrode surface material onto the positive electrode substrate to obtain a positive electrode sheet;

[0039] (2) Coating the negative electrode surface material onto the negative electrode substrate to obtain a negative electrode sheet;

[0040] (3) The separator, negative electrode and positive electrode are wound into an electrode assembly; the electrode assembly is inserted into the casing to obtain a prefabricated battery;

[0041] (4) Add electrolyte to the prefabricated battery to obtain the prefabricated battery after electrolyte addition;

[0042] (5) Cap the prefabricated battery and then seal it under a pressure of less than or equal to 3000 Pa to obtain a nickel-metal hydride battery.

[0043] According to the preparation method of the present invention, preferably, in step (1), the positive electrode substrate is pre-pressed and then coated with adhesive to obtain a coated positive electrode substrate; the positive electrode surface material is coated on the coated positive electrode substrate and then rolled to obtain a positive electrode pre-product; the positive electrode pre-product is softened and trimmed to obtain a positive electrode sheet;

[0044] In step (2), a slurry containing a negative electrode surface material is coated onto a negative electrode substrate to obtain a negative electrode substrate coated with a negative electrode surface material; the negative electrode substrate coated with a negative electrode surface material is dried and then pressed into a sheet to obtain a negative electrode preform; the negative electrode preform is softened and trimmed to obtain a negative electrode sheet.

[0045] According to the preparation method of the present invention, preferably, the electrolyte is added to the prefabricated battery by vacuum injection.

[0046] The nickel-metal hydride battery of the present invention has a long service life. Furthermore, the nickel-metal hydride battery has a high discharge capacity. The preparation method of the present invention can further improve the service life of the nickel-metal hydride battery. Detailed Implementation

[0047] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0048] Nickel-metal hydride batteries

[0049] The nickel-metal hydride battery of the present invention includes a positive electrode, a negative electrode, and an electrolyte. In some embodiments, the nickel-metal hydride battery further includes one or more of a separator and a casing.

[0050] Positive electrode sheet

[0051] The positive electrode sheet of the present invention includes a positive electrode surface material and a positive electrode substrate. The positive electrode surface material is loaded on the positive electrode substrate.

[0052] The positive electrode surface material comprises cobalt-coated spherical nickel hydroxide and transition metal oxides. The positive electrode surface material may also include a first binder. In some embodiments, the positive electrode surface material consists of cobalt-coated spherical nickel hydroxide, transition metal oxides, and a first binder.

[0053] The transition metal oxide is selected from one or more Group IIIB or Group IVB metal oxides. Examples of Group IIIB metal oxides include, but are not limited to, rare earth oxides. Examples of Group IVB metal oxides include, but are not limited to, zirconium oxide and titanium oxide.

[0054] According to one embodiment of the present invention, the transition metal oxide is selected from one or more of zirconium oxide or yttrium oxide. In some embodiments, the transition metal oxide is zirconium oxide. In other embodiments, the transition metal oxide is yttrium oxide.

[0055] The first binder may be selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene. In some embodiments, the first binder is polytetrafluoroethylene. In other embodiments, the first binder is styrene-butadiene rubber.

[0056] This type of positive electrode surface material can improve the lifespan and discharge capacity of nickel-metal hydride batteries.

[0057] The amount of cobalt-coated spherical nickel hydroxide used is 80 to 98 parts by weight; preferably 85 to 95 parts by weight; more preferably 87 to 90 parts by weight.

[0058] The amount of transition metal oxide used is 1 to 8 parts by weight; preferably 2 to 6 parts by weight; more preferably 3 to 5 parts by weight. In some embodiments, the amount of transition metal oxide used is 3 to 4 parts by weight.

[0059] The amount of the first adhesive can be 0.5 to 5 parts by weight; preferably 1 to 4 parts by weight; more preferably 2 to 3 parts by weight.

[0060] Controlling the amount of each substance within the above range helps to improve the lifespan and discharge capacity of nickel-metal hydride batteries.

[0061] The positive electrode substrate can be nickel foam.

[0062] The length of the positive electrode sheet can be 70–100 mm; preferably 80–95 mm; more preferably 85–90 mm. The width of the positive electrode can be 30–50 mm; preferably 40–45 mm. The thickness of the positive electrode can be 0.3–0.8 mm; preferably 0.5–0.65 mm.

[0063] The positive electrode sheet of the present invention can be a positive electrode sheet that has undergone softening and trimming treatment.

[0064] Negative electrode sheet

[0065] The negative electrode sheet of the present invention includes a negative electrode surface material and a negative electrode substrate. The negative electrode surface material is loaded on the negative electrode substrate.

[0066] The negative electrode surface material includes a La-Y-Ni hydrogen storage alloy, yttrium oxide, and a conductive agent. The negative electrode surface material may also include a second binder. In some embodiments, the negative electrode surface material consists of a La-Y-Ni hydrogen storage alloy, yttrium oxide, a conductive agent, and a second binder.

[0067] The La-Y-Ni hydrogen storage alloy has the following composition:

[0068] RE x Y y Ni d Mn a Al b M c

[0069] RE is selected from one or more of La, Ce, Sm, and Gd, and must contain La. In some embodiments, RE is La. In other embodiments, RE is La and Mm. Mm is selected from one or more of Ce, Sm, and Gd. Preferably, Mm is Sm. The molar ratio of RE to Mm can be (0.5–2):1; preferably (0.8–1.5):1; more preferably (1–1.2):1.

[0070] x represents the molar number of RE. 0.2≤x≤0.8; preferably, 0.3≤x≤0.6; more preferably, 0.4≤x≤0.5.

[0071] y represents the mole fraction of Y. x + y = 2. 1.2 ≤ y ≤ 1.8; preferably, 1.4 ≤ y ≤ 1.7; more preferably, 1.5 ≤ y ≤ 1.6.

[0072] 'a' represents the molar number of Mn. 0.1 ≤ a ≤ 0.4; preferably, 0.2 ≤ a ≤ 0.3.

[0073] b represents the molar fraction of Al. 0.1 ≤ b ≤ 0.4; preferably, 0.2 ≤ b ≤ 0.3.

[0074] M is selected from one or more of Co, Fe, and Cu. According to one embodiment of the present invention, M is Fe. c represents the molar fraction of M. 0.1 ≤ c ≤ 0.5; preferably, 0.2 ≤ c ≤ 0.4; more preferably, 0.3 ≤ c ≤ 0.4.

[0075] d represents the molar fraction of Ni. 6.7≤a+b+c+d≤7.2; preferably, 6.8≤a+b+c+d≤7.1; more preferably, 6.9≤a+b+c+d≤7.0. 6≤d≤6.8; preferably, 6.2≤d≤6.5; more preferably, 6.3≤d≤6.4.

[0076] According to one embodiment of the present invention, the composition of the La-Y-Ni hydrogen storage alloy is: La 0.2 Sm 0.2 Y 1.6 Ni 6.3 Mn 0.2 Al 0.2 Fe 0.3 .

[0077] The La-Y-Ni hydrogen storage alloy can be prepared using methods commonly used in the field, such as vacuum induction melting, gas atomization, and mechanical alloying; it can also be purchased from the Baotou Rare Earth Research Institute.

[0078] The conductive agent is selected from one or more of carbon black, acetylene black, and graphene. The graphene is conductive graphene. In some embodiments, the conductive agent is acetylene black. In other embodiments, the conductive agent is graphene. In still other embodiments, the conductive agent is carbon black.

[0079] The second binder may be selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene. In some embodiments, the second binder is polytetrafluoroethylene. In other embodiments, the second binder is styrene-butadiene rubber. In still other embodiments, the second binder is sodium carboxymethyl cellulose.

[0080] This type of negative electrode surface material can improve the lifespan and discharge capacity of nickel-metal hydride batteries.

[0081] The amount of La-Y-Ni hydrogen storage alloy used is 80-90 parts by weight; preferably 83-88 parts by weight; more preferably 85-87 parts by weight.

[0082] The amount of conductive agent used is 0.1 to 0.5 parts by weight; preferably 0.2 to 0.4 parts by weight; more preferably 0.2 to 0.3 parts by weight.

[0083] The amount of the second adhesive can be 8 to 12 parts by weight; preferably 9 to 11 parts by weight; more preferably 10 to 11 parts by weight.

[0084] The amount of yttrium oxide can be 4 to 6 parts by weight; preferably 4 to 5 parts by weight.

[0085] Controlling the amount of each substance within the above range helps to improve the lifespan and discharge capacity of nickel-metal hydride batteries.

[0086] The negative electrode substrate can be nickel-plated steel strip.

[0087] The length of the negative electrode sheet can be 105–150 mm; preferably 110–140 mm; more preferably 120–130 mm. The width of the negative electrode can be 30–50 mm; preferably 40–45 mm. The thickness of the negative electrode can be 0.05–0.4 mm; preferably 0.2–0.3 mm.

[0088] The negative electrode sheet of the present invention can be a negative electrode sheet that has undergone softening and trimming treatment.

[0089] Electrolyte

[0090] The electrolyte of the present invention comprises KOH, NaOH, LiOH, and water. In some embodiments, the electrolyte is composed of KOH, NaOH, LiOH, and water.

[0091] The amount of KOH used is 8 to 20 parts by weight; preferably 10 to 15 parts by weight; more preferably 12 to 14 parts by weight.

[0092] The amount of NaOH used is 13 to 25 parts by weight; preferably 15 to 20 parts by weight; more preferably 18 to 19 parts by weight.

[0093] The amount of LiOH used is 0.5 to 6 parts by weight; preferably 1 to 4 parts by weight; more preferably 2 to 3 parts by weight.

[0094] The amount of water used is 50 to 80 parts by weight; preferably 60 to 70 parts by weight; more preferably 65 to 67 parts by weight.

[0095] The electrolyte composition described above can improve the discharge capacity and lifespan of nickel-metal hydride batteries.

[0096] The electrolyte filling amount in each casing can be 2.5–4 g; preferably 2.7–3 g; more preferably 2.7–2.8 g. This can improve the discharge capacity and lifespan of the nickel-metal hydride battery.

[0097] Separator and case

[0098] A separator is located between the positive and negative electrodes. The separator can be a sulfonated separator or a grafted separator. According to one embodiment of the present invention, the separator is a sulfonated separator.

[0099] The outer casing can be made of steel. The positive electrode, negative electrode, and separator are all wound inside the casing. The electrolyte fills the casing.

[0100] <Preparation Methods of Nickel-Metal Hydride Batteries>

[0101] The method for preparing the nickel-metal hydride battery of the present invention includes the following steps: (1) positive electrode preparation step; (2) negative electrode preparation step; (3) winding step; (4) electrolyte addition step; and (5) sealing step.

[0102] Positive electrode sheet preparation step

[0103] The positive electrode surface material is coated onto the positive electrode substrate to obtain the positive electrode sheet. The composition of the positive electrode surface material, the selection of the positive electrode substrate, and the length, width, and height of the positive electrode sheet are as described above and will not be repeated here.

[0104] Specifically, the positive electrode substrate is pre-pressed and then coated with adhesive to obtain an adhesive-coated positive electrode substrate; a positive electrode surface material is coated onto the adhesive-coated positive electrode substrate and then rolled to obtain a positive electrode pre-product; the positive electrode pre-product is softened and trimmed to obtain a positive electrode sheet.

[0105] The material used for coating can be polytetrafluoroethylene (PTFE). A brush can be used to coat the positive electrode surface material onto the positive electrode substrate. A scraper can be used to control the thickness. After rolling, the electrode can be cut to obtain positive electrode sheets of appropriate size.

[0106] The process may also include the following steps: mixing cobalt-coated spherical nickel hydroxide, transition metal oxide, and a first binder to obtain the positive electrode surface material. Mixing can be performed in a mixer, such as a three-dimensional mixer. The mixing time can be 0.5–5 h; preferably 1–4 h; more preferably 1.5–3 h.

[0107] Negative electrode sheet preparation step

[0108] A slurry containing a negative electrode surface material is coated onto a negative electrode substrate to obtain a negative electrode sheet. The slurry containing the negative electrode surface material includes the negative electrode surface material and water. The slurry containing the negative electrode surface material can be composed of the negative electrode surface material and water. The composition of the negative electrode surface material, the selection of the negative electrode substrate, and the length, width, and height of the negative electrode sheet are as described above and will not be repeated here.

[0109] Specifically, a slurry containing a negative electrode surface material is coated onto a negative electrode substrate to obtain a negative electrode substrate coated with the negative electrode surface material; the negative electrode substrate coated with the negative electrode surface material is dried and then pressed into a sheet to obtain a negative electrode preform; the negative electrode preform is softened and trimmed to obtain a negative electrode sheet. Drying can be carried out in a vacuum drying oven. The drying time can be 10–30 hours; preferably 15–25 hours. The sheet pressing can be carried out in a roller mill. The sheet can be cut after pressing to obtain a negative electrode sheet of suitable size.

[0110] The process may also include the following steps: mixing La-Y-Ni hydrogen storage alloy powder, a conductive agent, a second binder, yttrium oxide, and deionized water to obtain a slurry containing a negative electrode surface material. The mixing time can be 0.3–5 h; preferably 0.5–3 h; more preferably 2–3 h.

[0111] Winding step

[0112] The separator, negative electrode, and positive electrode are wound into an electrode assembly; the electrode assembly is then inserted into a casing to obtain a prefabricated battery. The separator and casing are as described above and will not be repeated here.

[0113] The separator is located between the negative electrode and the positive electrode. The widths of the positive and negative electrode are aligned.

[0114] Electrolyte addition step

[0115] The electrolyte is added to the prefabricated battery to obtain the prefabricated battery with electrolyte added. The composition of the electrolyte is as described above and will not be repeated here.

[0116] Electrolyte can be added to the prefabricated battery using a vacuum injection method. The electrolyte can be added in multiple stages; for example, 2 to 8 times, or 3 to 5 times.

[0117] The amount of electrolyte added can be 2.5-4g; preferably 2.7-3g; more preferably 2.7-2.8g.

[0118] Sealing step

[0119] After adding liquid, prefabricate the battery cap, and then seal it under a pressure of less than or equal to 3000 Pa.

[0120] The cap can be made by welding.

[0121] The sealing pressure is less than or equal to 3000 Pa; preferably, the sealing pressure is 500–2500 Pa; more preferably, the sealing pressure is 1000–2000 Pa. This can improve the service life of nickel-metal hydride batteries.

[0122] The raw materials are described below:

[0123] La-Y-Ni hydrogen storage alloy powder has the following composition: La 0.2 Sm 0.2 Y 1.6 Ni 6.3 Mn 0.2 Al 0.2 Fe 0.3 .

[0124] Sulfonated diaphragm: Purchased from Laizhou Lianyou Jinhao New Material Co., Ltd.

[0125] Examples 1 to 5

[0126] (1) Cobalt-coated spherical nickel hydroxide, transition metal oxide, and a first binder are mixed in a mixer to obtain the positive electrode surface material. The foamed nickel is pre-pressed and tabs are formed to obtain pretreated foamed nickel. Polytetrafluoroethylene is coated on the surface of the pretreated foamed nickel to obtain coated foamed nickel. The positive electrode surface material is coated onto the coated foamed nickel using a brush, and the thickness is controlled by a scraper; then it is rolled and cut to obtain the positive electrode preform. The positive electrode preform is softened and trimmed to obtain the positive electrode sheet.

[0127] The specific parameters for this step are shown in Table 1:

[0128] Table 1

[0129]

[0130] (2) La-Y-Ni hydrogen storage alloy powder, conductive agent, second binder, yttrium oxide, and deionized water are slurried to obtain a slurry containing a negative electrode surface material. The slurry containing the negative electrode surface material is coated onto a nickel-plated steel strip and then dried in a vacuum drying oven to obtain a coated negative electrode substrate. The coated negative electrode substrate is pressed into sheets in a roller mill and then cut to obtain a negative electrode preform. The negative electrode preform is softened and trimmed to obtain a negative electrode sheet.

[0131] The specific parameters for this step are shown in Table 2:

[0132] Table 2

[0133]

[0134] (3) The positive electrode, negative electrode, and sulfonated separator are wound into an electrode assembly using a winding machine. The sulfonated separator is located between the positive and negative electrode. The widths of the positive and negative electrode are aligned. The electrode assembly is then inserted into a casing to obtain a prefabricated battery. The casing is made of steel.

[0135] (4) The electrolyte consisting of KOH, NaOH, LiOH and deionized water is added to the prefabricated battery in three separate steps using a vacuum injection method to obtain the prefabricated battery after adding the electrolyte.

[0136] The specific parameters for this step are shown in Table 3:

[0137] Table 3

[0138]

[0139] (5) After adding liquid, the prefabricated battery is welded with a cap, the cap is pressed into the outer shell, and then sealed on a sealing machine to obtain a nickel-metal hydride battery.

[0140] The specific sealing pressure is shown in Table 4:

[0141] Table 4

[0142] Serial number Example 1 Example 2 Example 3 Example 4 Example 5 Sealing pressure (Pa) 1000 1500 1800 2000 1300

[0143] Example 6

[0144] Except for the sealing pressure of 0.1 MPa in step (5), the rest is the same as in Example 1.

[0145] Comparative example 1

[0146] Except for the positive electrode surface material, which is composed of 87 parts by weight of cobalt-coated spherical nickel oxide, 3 parts by weight of zirconium oxide, 0.2 parts by weight of acetylene black and 2 parts by weight of styrene-butadiene rubber, and the slurry containing the negative electrode surface material, which is composed of 85 parts by weight of La-Y-Ni hydrogen storage alloy powder, 8 parts by weight of sodium carboxymethyl cellulose and 7 parts by weight of deionized water, the rest is the same as in Example 1.

[0147] Comparative example 2

[0148] Except for replacing yttrium oxide with zinc oxide in step (2), the rest is the same as in Example 1.

[0149] The discharge capacity and cycle number of the batteries obtained from the test examples and comparative examples are shown in Table 5 below.

[0150] Discharge capacity: Charge at 360mA for 6 hours, let stand for 15 minutes, and then discharge at 360mA to 1.0V.

[0151] Cycle count: Charge at 1800mA for 1.2 hours, let stand for 15 minutes, and then discharge at 1800mA to 1.0V. Repeat the charge and discharge cycle as described above until the battery's discharge capacity drops to 80% of the initial discharge capacity, and record the number of charge and discharge cycles.

[0152] Table 5

[0153] Serial number Discharge capacity (mAh) Charging and discharging cycle number (times) Example 1 1823 382 Example 2 1837 367 Example 3 1820 385 Example 4 1856 365 Example 5 1833 379 Example 6 1839 352 Comparative example 1 — 184 Comparative example 2 — 193

[0154] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A nickel-metal hydride battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte; the positive electrode includes a positive electrode surface material and a positive electrode substrate, and the negative electrode includes a negative electrode surface material and a negative electrode substrate; The positive electrode surface material includes: 80-98 parts by weight of cobalt-coated spherical nickel hydroxide; and Zirconia 1 to 8 parts by weight; The negative electrode surface material includes: 80-90 parts by weight of La-Y-Ni hydrogen storage alloy; Conductive agent 0.1 to 0.5 parts by weight; 4 to 6 parts by weight of yttrium oxide; The conductive agent is selected from one or both of carbon black and graphene; The La-Y-Ni hydrogen storage alloy has the following composition: RE x AND y Neither d Mn a To the b M c Where RE is La and Sm, and M is selected from one or more of Co, Fe, and Cu; Wherein, 0.4≤x≤0.5, 1.5≤y≤1.6, x+y=2, 0.2≤a≤0.3, 0.2≤b≤0.3, 0.3≤c≤0.4, 6.3≤d≤6.4, 6.7≤a+b+c+d≤7.2; x, y, a, b, c, and d represent the molar fractions of each element. The electrolyte comprises:

2. The nickel-metal hydride battery according to claim 1, characterized in that, The conductive agent is acetylene black.

3. The nickel-metal hydride battery according to claim 1, characterized in that: The positive electrode sheet has a length of 70–100 mm, a width of 30–50 mm, and a thickness of 0.3–0.8 mm. The negative electrode sheet has a length of 105–150 mm, a width of 30–50 mm, and a thickness of 0.05–0.4 mm.

4. The nickel-metal hydride battery according to claim 1, characterized in that, The positive electrode substrate is nickel foam, and the negative electrode substrate is nickel-plated steel strip.

5. The nickel-metal hydride battery according to claim 1, characterized in that: The positive electrode surface material further includes a first binder, wherein the first binder is selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene; The negative electrode surface material further includes a second binder, which is selected from one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, or polytetrafluoroethylene.

6. The nickel-metal hydride battery according to any one of claims 1 to 5, characterized in that, The nickel-metal hydride battery also includes a separator and a casing; The separator is located between the positive electrode and the negative electrode, and the separator is a sulfonated separator or a grafted separator; The positive electrode, negative electrode, separator, and electrolyte are located inside the outer casing.

7. The method for preparing a nickel-metal hydride battery according to claim 6, characterized in that, Includes the following steps: (1) Coating the positive electrode surface material onto the positive electrode substrate to obtain a positive electrode sheet; (2) Coating the negative electrode surface material onto the negative electrode substrate to obtain a negative electrode sheet; (3) Wind the diaphragm, negative electrode, and positive electrode into an electrode assembly; The electrode assembly is inserted into the casing to obtain a prefabricated battery; (4) Add electrolyte to the prefabricated battery to obtain the prefabricated battery after electrolyte addition; (5) Cap the prefabricated battery and then seal it under a pressure of less than or equal to 3000 Pa to obtain a nickel-metal hydride battery.

8. The preparation method according to claim 7, characterized in that: In step (1), the positive electrode substrate is pre-pressed and then coated with adhesive to obtain a coated positive electrode substrate; the positive electrode surface material is coated on the coated positive electrode substrate and then rolled to obtain a positive electrode pre-product; the positive electrode pre-product is softened and trimmed to obtain a positive electrode sheet; In step (2), a slurry containing a negative electrode surface material is coated onto a negative electrode substrate to obtain a negative electrode substrate coated with a negative electrode surface material; the negative electrode substrate coated with a negative electrode surface material is dried and then pressed into a sheet to obtain a negative electrode preform; the negative electrode preform is softened and trimmed to obtain a negative electrode sheet.

9. The preparation method according to claim 8, characterized in that, Electrolyte is added to the prefabricated battery using a vacuum injection method.

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