Zinc-nickel cylindrical battery cell

Abstract

The invention discloses a zinc-nickel cylindrical battery cell, which belongs to the technical field of energy storage and comprises a nickel positive electrode, a zinc negative electrode, a negative electrode current collector, a diaphragm and an insulating layer, the negative current collector, the zinc negative electrode, the diaphragm and the nickel positive electrode are sequentially wound and attached from inside to outside; the zinc negative electrode covers the two surfaces of the nickel positive electrode and is positioned on the outermost side after being wound; the insulating layer is wound and attached to the exposed surface of the zinc negative electrode on the side surface of the battery cell cylinder; active substances I are loaded on two surfaces of the nickel positive electrode; and an active substance II is loaded on the single side of the zinc negative electrode. The battery cell can be arranged in the nickel-plated steel cylindrical battery shell without obvious side reaction, so that the service life of the battery is effectively prolonged, and the reliability of the battery is effectively improved; according to the battery cell with the structure, the nickel positive electrode and the zinc negative electrode can easily form a good electronic path with the positive electrode and the negative electrode of the battery shell; the two surfaces of the negative electrode current collector and the non-loaded electrode material surface of the zinc negative electrode have pressing force due to the winding effect, and the zinc negative electrode and the current collector have a relatively large contact area, so that the uniform distribution of negative electrode current is facilitated.

Description

Technical Field

[0001] This application belongs to the technical field of energy storage, and particularly relates to a zinc-nickel cylindrical battery cell. Background Art

[0002] Compared with organic lithium-ion batteries and organic sodium-ion batteries, aqueous zinc-nickel secondary batteries have obvious advantages in terms of safety and have broad application prospects in the fields of power tools and low-speed electric vehicles. Cylindrical batteries have a long development time, high standardization, mature processes, good heat dissipation, and high shell pressure resistance. Considering the voltage window of the aqueous electrolyte and the working voltage of the zinc-nickel battery, the development of cylindrical zinc-nickel batteries will better meet the market demand.

[0003] The zinc-nickel cylindrical battery cell needs to include a wound nickel positive electrode, a zinc negative electrode, and a separator. After the separator is placed between the positive and negative electrodes and wound into a cylinder, it is placed into the battery case. The positive and negative electrodes do not conduct electrons. The nickel positive electrode and the zinc negative electrode respectively form an electron path with the positive and negative electrodes of the battery. After injecting the electrolyte, it can start working according to the charge and discharge procedure. Cylindrical batteries generally use nickel-plated steel shells as the battery case. The traditional structure with the negative electrode on the outermost side of the cell inevitably causes electron conduction between nickel and zinc in the alkaline electrolyte, aggravating the occurrence of side reactions and having an extremely adverse impact on the battery performance. Summary of the Invention

[0004] To solve the above technical problems, this application provides a zinc-nickel cylindrical battery cell, which can effectively avoid electron conduction between the zinc negative electrode and the nickel-plated cylindrical steel shell, and effectively reduce the occurrence of side reactions.

[0005] To achieve the above invention purpose, this application provides the following technical solutions:

[0006] On the one hand, this application provides a zinc-nickel cylindrical battery cell, including a nickel positive electrode, a zinc negative electrode, a negative current collector, a separator, and an insulating layer;

[0007] The negative current collector, zinc negative electrode, separator, and nickel positive electrode are wound and adhered to each other from the inside out to form a cell cylinder;

[0008] The zinc negative electrode covers both sides of the nickel positive electrode and is on the outermost side after winding;

[0009] The insulating layer is wound and adhered to the outside of the zinc negative electrode exposed on the side of the cell cylinder;

[0010] The nickel positive electrode is double-sidedly loaded with active material I;

[0011] The zinc negative electrode is single-sidedly loaded with active material II.

[0012] Optionally, the active material I includes nickel hydroxide;

[0013] The active substance II is selected from at least one of zinc oxide, zinc powder, and zinc hydroxide.

[0014] Optionally, the nickel positive electrode, the zinc negative electrode, the separator, and the insulating layer are independently rectangular.

[0015] Optionally, the zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle to the active substance surface, the folding line is parallel to the reel, and the nickel positive electrode is placed between the active substance surfaces of the zinc negative electrode.

[0016] Optionally, the separator is located between the nickel positive electrode and the zinc negative electrode.

[0017] Optionally, the negative electrode current collector includes a negative electrode fitting portion and an ear portion;

[0018] The negative electrode fitting portion and the ear portion are independently rectangular;

[0019] The negative electrode fitting portion is attached to one side of the folded zinc negative electrode;

[0020] The long side of the ear portion is collinear with the short side of the negative electrode fitting portion;

[0021] The short side of the ear portion is collinear with the long side of the negative electrode fitting portion;

[0022] The ear portion is close to the folding line side;

[0023] The width of the short side of the ear portion is 1 to 5 mm.

[0024] Preferably, the width of the short side of the ear portion is 2 to 4 mm.

[0025] Optionally, the width of the short side of the ear portion is independently selected from any value of 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or the range value between any two of them.

[0026] Optionally, one side of the nickel positive electrode includes a portion without loaded active substance;

[0027] The portion without loaded active substance is rectangular;

[0028] The long side of the portion without loaded active substance coincides with and is equal in length to the short side of the nickel positive electrode;

[0029] The width of the short side of the portion without loaded active substance is 4 to 10 mm.

[0030] Preferably, the width of the short side of the portion without loaded active substance is 5 to 8 mm.

[0031] Optionally, the short side width of the portion without the loaded active material is independently selected from any value among 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or a range value between any two of them.

[0032] Optionally, the side of the nickel positive electrode containing the portion without the loaded active material is placed facing away from the negative electrode current collector side.

[0033] Optionally, one end of the portion without the loaded active material of the nickel positive electrode is placed away from the zinc negative electrode folding line side.

[0034] Optionally, the zinc-nickel cylindrical battery cell starts winding from the zinc negative electrode folding line and winds inward along one side of the negative electrode current collector.

[0035] Optionally, after winding, the side of the nickel positive electrode without the loaded active material faces outward and is located on the outermost side, not completely wrapped by the separator, the zinc negative electrode and the insulating layer.

[0036] Optionally, after winding, the zinc negative electrode facing the side of the nickel positive electrode without the loaded active material extends 1 - 3 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode and continues along the winding direction.

[0037] Preferably, after winding, the zinc negative electrode facing the side of the nickel positive electrode without the loaded active material extends 1.5 - 2.5 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode and continues along the winding direction.

[0038] Optionally, the separator on the side facing the side of the nickel positive electrode without the loaded active material extends 1 - 3 mm along the long side direction based on the short side of the zinc negative electrode facing the side of the nickel positive electrode without the loaded active material and continues along the winding direction.

[0039] Preferably, the separator on the side facing the side of the nickel positive electrode without the loaded active material extends 1.5 - 2.5 mm along the long side direction based on the short side of the zinc negative electrode facing the side of the nickel positive electrode without the loaded active material and continues along the winding direction.

[0040] Optionally, after winding, the separator facing the side of the nickel positive electrode with the loaded active material extends 1 - 3 mm along the long side direction based on the short side of the rectangle of the loaded active material portion of the side of the nickel positive electrode with the loaded active material and extends along the winding direction.

[0041] Preferably, after winding, the separator facing the side of the nickel positive electrode with the loaded active material extends 1.5 - 2.5 mm along the long side direction based on the short side of the rectangle of the loaded active material portion of the side of the nickel positive electrode with the loaded active material and extends along the winding direction.

[0042] Optionally, the zinc negative electrode facing the nickel positive electrode with the part of the surface not loaded with the active material is shortened by 1-3 mm in the winding direction based on the short side of the rectangle of the separator facing the nickel positive electrode with the part of the surface not loaded with the active material along the long side direction.

[0043] Preferably, the zinc negative electrode facing the nickel positive electrode with the part of the surface not loaded with the active material is shortened by 1.5-2.5 mm in the winding direction based on the short side of the rectangle of the separator facing the nickel positive electrode with the part of the surface not loaded with the active material along the long side direction.

[0044] Optionally, the insulating layer is attached to the zinc negative electrode exposed on the outside of the battery cell, neither completely covering the part of the nickel positive electrode not loaded with the active material, nor leaving any exposed part of the zinc negative electrode on the side of the cylindrical battery cell, and in the winding direction, based on the short side edge of the outermost zinc negative electrode, the rectangular edge of the insulating layer extends outward by 1-5 mm.

[0045] Preferably, the insulating layer is attached to the zinc negative electrode exposed on the outside of the battery cell, neither completely covering the part of the nickel positive electrode not loaded with the active material, nor leaving any exposed part of the zinc negative electrode on the side of the cylindrical battery cell, and in the winding direction, based on the short side edge of the outermost zinc negative electrode, the rectangular edge of the insulating layer extends outward by 2-4 mm.

[0046] Optionally, the insulating layer includes at least one of polyethylene, polypropylene, and polytetrafluoroethylene.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] The battery cell of the present application can be placed in a nickel-plated steel cylindrical battery case without significant side reactions, effectively improving the battery life and reliability; the battery cell with the structure of the present application can easily form a good electronic path between the nickel positive electrode and the zinc negative electrode and the positive and negative electrodes of the battery case; due to the winding effect, both sides of the negative electrode current collector have a pressing force on the zinc negative electrode with the electrode material surface not loaded, and the contact area between the zinc negative electrode and the current collector increases, making the negative electrode current distribution more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 It is a schematic structural diagram of the wound battery cell of the zinc-nickel cylindrical battery of the present application (note: 1 represents the positive electrode; 101 represents the part of the positive electrode not loaded with the active material; 2 represents the zinc negative electrode; 3 represents the negative electrode current collector; 301 represents the tab; 4 represents the separator; 5 represents the insulating layer);

[0051] Figure 2 For the performance of the zinc-nickel cylindrical battery of the battery cell of this application. Specific embodiments

[0052] The following will further elaborate on this application in combination with specific embodiments. The following descriptions are only several embodiments of this application and do not impose any form of limitation on this application. Although this application is disclosed as preferred embodiments, it is not intended to limit this application. Any person skilled in the relevant art can make some changes or modifications within the scope of the technical solutions of this application by using the disclosed technical content, which are equivalent to equivalent implementation cases and all fall within the scope of the technical solutions.

[0053] Unless otherwise specified, the raw materials in the embodiments of this application are purchased through commercial channels and used directly without any special treatment.

[0054] Unless otherwise specified, the analysis methods in the embodiments adopt the conventional settings and conventional analysis methods of the instruments or equipment.

[0055] Embodiment 1

[0056] The cylindrical battery cell described in this application is assembled in the following manner:

[0057] As Figure 1 shown, it includes a nickel positive electrode, a zinc negative electrode, a negative electrode current collector, a separator, and an insulating layer. The positive electrode nickel foam substrate is double-sidedly loaded with active substances, and the zinc negative electrode is a zinc foil single-sidedly loaded with active substances;

[0058] The zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle on the active substance surface, and the nickel positive electrode is placed between the active substance surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the folding line is parallel to the reel;

[0059] The negative electrode current collector includes a rectangular negative electrode zinc foil bonding part and an ear part; the negative electrode bonding part is bonded to one side of the folded zinc negative electrode; the ear part is rectangular, the long side of the ear part is collinear with the short side of the zinc foil bonding part, and the short side of the ear part is collinear with the long side of the zinc foil bonding part; the ear part is close to the folding line side; the width of the short side of the rectangular ear is 4 mm;

[0060] One side of the nickel positive electrode includes a rectangular part without loaded active substances. The long side of the part without loaded active substances coincides with and is equal to the short side of the positive electrode rectangle, and the width of the short side of the part without loaded active substances is 8 mm;

[0061] The side of the nickel positive electrode containing the surface without loaded active substances is placed facing away from the negative electrode current collector; one end of the rectangular part without loaded active substances of the nickel positive electrode is placed away from the folding line side of the zinc negative electrode;

[0062] The winding of the battery cell starts from the folding line of the zinc negative electrode and winds inward along one side of the negative current collector; after winding, the side of the positive electrode without loaded active material faces outward and is located on the outermost side, and there is no separator wrapping the zinc negative electrode.

[0063] After winding, the zinc negative electrode facing the nickel positive electrode without the side of the unloaded active material extends 2 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode cell and continues to extend along the winding direction; the separator on the side facing the nickel positive electrode without the side of the unloaded active material extends 2 mm along the long side direction based on the short side of the zinc negative electrode facing the nickel positive electrode without the side of the unloaded active material and continues to extend along the winding direction.

[0064] After winding, the separator facing the nickel positive electrode with the side of the unloaded active material extends 2 mm along the long side direction based on the short side of the rectangle of the rectangular part of the loaded active material with the side of the unloaded active material on the outermost side of the nickel positive electrode cell and extends along the winding direction; the zinc negative electrode facing the nickel positive electrode with the side of the unloaded active material shortens 2 mm along the long side direction based on the short side of the rectangle of the separator facing the nickel positive electrode with the side of the unloaded active material and extends along the winding direction.

[0065] The insulating layer is rectangular and fits with the zinc negative electrode exposed on the outside of the battery cell. It is necessary to ensure that it does not completely cover the part of the nickel positive electrode without loaded active material, and at the same time ensure that there is no exposed part of the zinc negative electrode on the side of the cylindrical battery cell, and the rectangular edge of the insulating layer extends 4 mm outward in the reel direction; the material of the insulating layer is polyethylene.

[0066] The electrolyte uses 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive active material is nickel hydroxide (92%), and also includes cobalt oxide (2%), carbon nanotubes (2%) and binder (4%); the negative active material is zinc oxide and zinc powder (mass ratio is 5:3, accounting for 88% in total), and also includes carbon nanotubes (5%), indium hydroxide (2%) and binder (5%).

[0067] The performance is as Figure 2 shown. For this cylindrical battery, it is charged and discharged in a constant current of 0.5 A, the discharge cut-off voltage is 1.2 V, the Coulomb efficiency is greater than 90%, the energy efficiency is greater than 80%, the discharge capacity is greater than 1.2 Ah, and it can be cycled more than 50 times.

[0068] Example 2

[0069] The cylindrical battery cell described in this application is used, but a separator is used as the insulating layer. The separator facing the positive electrode without the coated active material surface after winding is continued to extend outward along the winding direction so that it wraps the surface of the zinc negative electrode without the coated active material. Based on the edge of the short side of the outermost zinc negative electrode, it continues to extend 3 mm, but it is necessary to ensure that there is an exposed part of the positive electrode without loaded active material on the outside of the battery cell.

[0070] Assemble in the following way:

[0071] It includes a nickel positive electrode, a zinc negative electrode, a negative current collector, and a separator. The nickel foam substrate of the positive electrode is loaded with active materials on both sides, and the zinc negative electrode is a zinc foil loaded with active materials on one side.

[0072] The zinc negative electrode is folded face-to-face along the perpendicular line of the long side of the rectangle on the active material surface, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the folding line is parallel to the reel.

[0073] The negative current collector includes a rectangular negative zinc foil bonding part and an ear part; the negative bonding part is bonded to one side of the folded zinc negative electrode; the ear part is rectangular, the long side of the ear part is collinear with the short side of the zinc foil bonding part, and the short side of the ear part is collinear with the long side of the zinc foil bonding part; the ear part is close to the folding line side; the short side width of the rectangular ear is 4 mm.

[0074] One side of the nickel positive electrode includes a rectangular part without loaded active materials, the long side of the part without loaded active materials coincides with and is equal in length to the short side of the positive electrode rectangle, and the short side width of the part without loaded active materials is 8 mm.

[0075] The side of the nickel positive electrode containing the surface without loaded active materials is placed facing away from the negative current collector; one end of the rectangular part without loaded active materials of the nickel positive electrode is placed away from the folding line side of the zinc negative electrode.

[0076] The winding of the battery cell starts from the folding line of the zinc negative electrode and winds inward along one side of the negative current collector; after winding, the side of the positive electrode without loaded active materials faces outward and is located on the outermost side, and there is no separator wrapping the zinc negative electrode.

[0077] After winding, the zinc negative electrode facing the nickel positive electrode and not containing the surface without loaded active materials extends 2 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode battery cell and continues along the winding direction.

[0078] After winding, the separator facing the nickel positive electrode and containing the surface without loaded active materials shortens 2 mm along the long side direction based on the short side of the rectangle of the part of the nickel positive electrode battery cell's outermost surface containing the surface without loaded active materials and loaded with active materials and along the winding direction; the zinc negative electrode facing the nickel positive electrode and containing the surface without loaded active materials shortens 2 mm along the long side direction based on the short side of the rectangle of the separator facing the nickel positive electrode and containing the surface without loaded active materials and along the winding direction.

[0079] The electrolyte used is 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive active material is nickel hydroxide (92%), and also includes cobaltous oxide (2%), carbon nanotubes (2%), and binder (4%); the negative active material is zinc oxide and zinc powder (mass ratio 5:3, totaling 88%), and also includes carbon nanotubes (5%), indium hydroxide (2%), and binder (5%).

[0080] The cylindrical battery is charged and discharged in a constant current of 0.5 A. The discharge cut-off voltage is 1.2 V, the Coulomb efficiency is greater than 90%, the energy efficiency is greater than 80%, the discharge capacity is greater than 1.2 Ah, and it can be cycled more than 50 times.

[0081] Comparative Example 1

[0082] The cylindrical battery cell does not use a negative current collector and an insulating layer, but uses a positive ear. The conduction of negative electrons is achieved by the contact between the zinc-coated side of the zinc negative electrode and the cylindrical outer shell of the cylindrical battery. The positive electrode uses a rectangular nickel ear, and the ear is welded to the part of the positive electrode without loaded active material.

[0083] The assembly method is as follows:

[0084] It includes a nickel positive electrode, a zinc negative electrode, and a separator. The nickel positive electrode is loaded with active material on both sides, and the zinc negative electrode is a zinc foil loaded with active material on one side;

[0085] The zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle on the active material surface, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the folding line is parallel to the reel;

[0086] A nickel rectangular ear is used, with a long side of 40 mm, a short side of 3 mm, and a thickness of 100 microns. The ear is welded to the part of the positive electrode without loaded active material by ultrasonic welding. The long side of the ear is perpendicular to the long side of the nickel foam, the fitting length of the long side of the ear and the nickel foam is 10 mm, and the long side of the ear is flush with the short side of the nickel positive electrode.

[0087] The winding of the battery cell starts from the folding line of the zinc negative electrode and winds inward; after winding, the outermost layer of the cylindrical side of the battery cell is the zinc foil without loaded negative active material; there are negative electrodes with loaded active material on both sides of the nickel positive electrode facing it, and the positive and negative electrodes are separated by a separator. The short side edges of the zinc negative electrodes on both sides of the nickel positive electrode extend 3 mm along the winding direction of the battery cell, based on the short side edge of the nickel positive electrode. As for the short side edge of the rectangular separator between the positive and negative electrodes along the winding direction of the battery cell, it extends 3 mm based on the extremely short side edge of the zinc negative electrode.

[0088] The electrolyte uses 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive active material is nickel hydroxide (92%), and also includes cobalt oxide (2%), carbon nanotubes (2%), and binder (4%). The negative active material is zinc oxide and zinc powder (mass ratio 5:3, accounting for 88% in total), and also includes carbon nanotubes (5%), indium hydroxide (2%), and binder (5%).

[0089] The cylindrical battery is charged and discharged in a constant current of 0.5 A. The discharge cut-off voltage is 1.2 V, the Coulomb efficiency is greater than 90%, the energy efficiency is greater than 80%, the discharge capacity is greater than 1.2 Ah, and the number of cycles is less than 30 times.

[0090] Comparative Example 2

[0091] The cylindrical battery cell does not use an insulating layer, but uses a positive electrode with tabs and a rectangular copper foil negative electrode current collector without tabs. The positive electrode uses a rectangular nickel tab with a short side of 4 mm, a long side of 90 mm, and a thickness of 100 microns; the tab is welded to the part of the positive electrode without loaded active material by ultrasonic welding. The long side of the tab is perpendicular to the long side of the nickel positive electrode, the long side of the tab is attached to the short side of the nickel positive electrode on the side without loaded active material, the short side of the tab is attached to one long side of the nickel positive electrode, and the overlapping area between the tab and the part of the nickel positive electrode without loaded active material is rectangular. The short side length of the rectangular copper foil current collector is 55 mm, and the long side length is 220 mm.

[0092] The assembly method is as follows:

[0093] It includes a nickel positive electrode, a zinc negative electrode, a negative copper foil current collector, and a separator. The nickel positive electrode is double-sidedly loaded with active material, and the zinc negative electrode is a zinc foil single-sidedly loaded with active material;

[0094] The zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle on the active material surface, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the folding line is parallel to the reel; the negative copper foil current collector is attached to the side of the zinc negative electrode without coated active material, and one short side of the negative copper foil current collector coincides with the folding line.

[0095] The winding of the battery cell starts from the folding line of the zinc negative electrode and winds inward along one side of the negative current collector; the nickel positive electrode with active material loaded on both sides faces the negative electrode and the positive and negative electrodes are separated by the separator; the short side edges of the zinc negative electrode on both sides of the nickel positive electrode extend 3 mm along the winding direction of the battery cell based on the short side edge of the nickel positive electrode; the short side edge of the rectangular separator placed between the positive and negative electrodes extends 3 mm along the winding direction of the battery cell based on the extremely short side edge of the zinc negative electrode. After winding, the negative copper foil current collector wraps the outermost layer of the battery cell.

[0096] The electrolyte uses 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive electrode active material is nickel hydroxide (92%), and also includes cobaltous oxide (2%), carbon nanotubes (2%), and binder (4%); the negative electrode active material is zinc oxide and zinc powder (mass ratio 5:3, accounting for 88% in total), and also includes carbon nanotubes (5%), indium hydroxide (2%), and binder (5%).

[0097] This cylindrical battery is charged and discharged in a constant current of 0.5 A. The discharge cut-off voltage is 1.2 V, the Coulomb efficiency is greater than 90%, the energy efficiency is greater than 80%, the discharge capacity is greater than 1.2 Ah, and the number of cycles is less than 30 times.

[0098] Comparative Example 3

[0099] The cylindrical battery cell described in this application but without using an insulating layer is assembled in the following manner:

[0100] It includes a nickel positive electrode, a zinc negative electrode, a negative electrode current collector, and a separator. The positive electrode nickel foam substrate is double-sidedly loaded with active materials, and the zinc negative electrode is a zinc foil single-sidedly loaded with active materials;

[0101] The zinc negative electrode is folded face-to-face along the perpendicular line of the long side of the rectangle on the active material surface, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the folding line is parallel to the reel;

[0102] The negative electrode current collector includes a rectangular negative electrode zinc foil bonding part and an ear part; the negative electrode bonding part is bonded to one side of the folded zinc negative electrode; the ear part is rectangular, the long side of the ear part is collinear with the short side of the zinc foil bonding part, and the short side of the ear part is collinear with the long side of the zinc foil bonding part; the ear part is close to the folding line side; the short side width of the rectangular ear is 4 mm;

[0103] One side of the nickel positive electrode includes a rectangular part without loaded active materials, the long side of the part without loaded active materials coincides with and is equal in length to the short side of the positive electrode rectangle, and the short side width of the part without loaded active materials is 8 mm;

[0104] The side of the nickel positive electrode containing the surface without loaded active materials is placed facing away from the negative electrode current collector; one end of the rectangular part without loaded active materials of the nickel positive electrode is placed away from the side of the zinc negative electrode folding line;

[0105] The winding of the battery cell starts from the folding line of the zinc negative electrode and winds inward along one side of the negative electrode current collector; after winding, the side of the positive electrode without loaded active materials faces outward and is located on the outermost side, and there is no separator wrapping the zinc negative electrode;

[0106] After winding, the zinc negative electrode facing the nickel positive electrode without the surface without loaded active materials extends 2 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode battery cell and continues to extend along the winding direction; the separator on the side facing the nickel positive electrode without the surface without loaded active materials extends 2 mm along the long side direction based on the short side of the zinc negative electrode facing the nickel positive electrode without the surface without loaded active materials and continues to extend along the winding direction;

[0107] After winding, the separator facing the nickel positive electrode with the surface without loaded active materials extends 2 mm along the long side direction based on the short side of the rectangle of the part of the nickel positive electrode battery cell with the surface without loaded active materials and loaded with active materials and extends along the winding direction; the zinc negative electrode facing the nickel positive electrode with the surface without loaded active materials shortens 2 mm along the long side direction based on the short side of the rectangle of the separator facing the nickel positive electrode with the surface without loaded active materials and extends along the winding direction;

[0108] The electrolyte uses 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive active material is nickel hydroxide (92%), and also includes cobaltous oxide (2%), carbon nanotubes (2%) and binder (4%). The negative active material is zinc oxide and zinc powder (mass ratio 5:3, accounting for 88% in total), and also includes carbon nanotubes (5%), indium hydroxide (2%) and binder (5%).

[0109] The battery is short-circuited, generating a large amount of gas, and the battery cannot be charged or discharged.

[0110] Comparative Example 4

[0111] The cylindrical battery cell described in the present application is used, but the negative current collector is not used, and only the copper tab is directly welded to the negative zinc foil. The used copper rectangular tab has a long side of 40 mm, a short side of 3 mm, and a thickness of 100 microns. The tab is welded to the negative zinc foil by ultrasonic welding. The long side of the tab coincides with the fold line, and the part where the long side of the tab fits the zinc foil is rectangular, with a long side of 10 mm.

[0112] The battery cell is assembled in the following manner:

[0113] It includes a nickel positive electrode, a zinc negative electrode, a separator and an insulating layer. The positive nickel foam substrate is double-sidedly loaded with active material, and the zinc negative electrode is a zinc foil single-sidedly loaded with active material;

[0114] The zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle on the active material surface, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; the separator is located between the positive and negative electrodes; the fold line is parallel to the reel;

[0115] One side of the nickel positive electrode includes a rectangular part without loaded active material. The long side of the part without loaded active material coincides with and is equal in length to the short side of the positive rectangle, and the width of the short side of the part without loaded active material is 8 mm;

[0116] The nickel positive electrode with the surface without loaded active material is placed facing the outside of the winding; one end of the rectangular part without loaded active material of the nickel positive electrode is placed away from the side of the zinc negative electrode fold line;

[0117] The winding of the battery cell starts from the fold line of the zinc negative electrode and winds inwards; after winding, the side of the positive electrode without loaded active material faces outwards and is located on the outermost side, and the insulating layer, the separator and the zinc negative electrode are wrapped;

[0118] After winding, the zinc negative electrode facing the nickel positive electrode without the surface without loaded active material extends 2 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode battery cell and continues along the winding direction; the separator on the side facing the nickel positive electrode without the surface without loaded active material extends 2 mm along the long side direction based on the short side of the zinc negative electrode facing the nickel positive electrode without the surface without loaded active material and continues along the winding direction;

[0119] After winding, the separator facing the nickel positive electrode with the side without loaded active material extends 2 mm along the long side direction based on the short side of the rectangle of the rectangular part of the nickel positive electrode cell's outermost side without loaded active material along the winding direction; the zinc negative electrode facing the nickel positive electrode with the side without loaded active material shortens 2 mm along the long side direction based on the short side of the rectangle of the separator facing the nickel positive electrode with the side without loaded active material along the winding direction.

[0120] The insulating layer is rectangular and is attached to the zinc negative electrode exposed on the outside of the cell. It is necessary to ensure that it does not completely cover the part of the nickel positive electrode without loaded active material, and also ensure that there is no exposed part of the zinc negative electrode on the side of the cylindrical cell, and the rectangular edge of the insulating layer extends 4 mm outward in the reel direction; the material of the insulating layer is polyethylene.

[0121] The electrolyte uses 4M potassium hydroxide + 2M potassium fluoride + 1M potassium carbonate; the positive electrode active material is nickel hydroxide (92%), and also includes cobalt oxide (2%), carbon nanotubes (2%) and binder (4%), and the negative electrode active material is zinc oxide and zinc powder (mass ratio is 5:3, accounting for 88% in total), and also includes carbon nanotubes (5%), indium hydroxide (2%) and binder (5%).

[0122] This cylindrical battery is charged and discharged in a constant current of 0.5 A. The discharge cut-off voltage is 1.2 V, the Coulomb efficiency is greater than 90%, the energy efficiency is greater than 80%, the discharge capacity is greater than 1.2 Ah, and the number of cycles is less than 30 times.

[0123] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the technical content disclosed above is equivalent to equivalent implementation cases and all belong to the scope of the technical solution.

Claims

1. A zinc-nickel cylindrical battery cell, characterized in that, It includes a nickel positive electrode, a zinc negative electrode, a negative electrode current collector, a separator, and an insulating layer; The negative electrode current collector, the zinc negative electrode, the separator, and the nickel positive electrode are wound and adhered to each other in sequence from the inside out to form a cylindrical battery cell; The zinc negative electrode covers both sides of the nickel positive electrode and is located on the outermost side after winding; The insulating layer is wound and adhered to the outside of the zinc negative electrode exposed on the side of the cylindrical battery cell; The nickel positive electrode is double-sidedly loaded with active material I; The zinc negative electrode is single-sidedly loaded with active material II.

2. The zinc-nickel cylindrical battery cell according to claim 1, characterized in that, The active material I includes nickel hydroxide; The active material II is selected from at least one of zinc oxide, zinc powder, and zinc hydroxide.

3. The zinc-nickel cylindrical battery cell according to claim 1 or 2, characterized in that, The nickel positive electrode, the zinc negative electrode, the separator, and the insulating layer are independently rectangular; Preferably, the zinc negative electrode is folded face to face along the perpendicular line of the long side of the rectangle on the active material surface, and the folding line is parallel to the reel, and the nickel positive electrode is placed between the active material surfaces of the zinc negative electrode; Preferably, the separator is located between the nickel positive electrode and the zinc negative electrode.

4. The zinc-nickel cylindrical battery cell according to claim 3, characterized in that, The negative electrode current collector includes a negative electrode fitting part and an ear part; The negative electrode fitting part and the ear part are independently rectangular; The negative electrode fitting part is adhered to one side of the folded zinc negative electrode; The long side of the ear part is collinear with the short side of the negative electrode fitting part; The short side of the ear part is collinear with the long side of the negative electrode fitting part; The ear part is close to the folding line side; The width of the short side of the ear part is 1 - 5 mm.

5. The zinc-nickel cylindrical battery cell according to claim 4, characterized in that, One side of the nickel positive electrode contains a part without loaded active material; The part without loaded active material is rectangular; The long side of the part without loaded active material coincides with and is equal in length to the short side of the nickel positive electrode; The width of the short side of the part without loaded active material is 4 - 10 mm.

6. The zinc-nickel cylindrical battery cell according to claim 5, characterized in that, The side of the nickel positive electrode containing the part without loaded active material is placed on the side facing away from the negative electrode current collector; Preferably, one end of the part of the nickel positive electrode without loaded active material is placed away from the side of the zinc negative electrode folding line.

7. The zinc-nickel cylindrical battery cell according to claim 6, characterized in that, The zinc-nickel cylindrical battery cell starts winding from the folding line of the zinc negative electrode and winds inward along one side of the negative electrode current collector; Preferably, after winding, the side of the nickel positive electrode without loaded active material faces outward and is located on the outermost side, and is not completely wrapped by the separator, the zinc negative electrode, and the insulating layer.

8. The zinc-nickel cylindrical battery cell according to claim 7, characterized in that, After winding, the zinc negative electrode facing the side of the nickel positive electrode without the part without loaded active material extends 1 - 3 mm along the long side direction based on the short side of the outermost rectangle of the nickel positive electrode and continues along the winding direction; Preferably, the separator on the side facing the side of the nickel positive electrode without the part without loaded active material extends 1 - 3 mm along the long side direction based on the short side of the zinc negative electrode on the side facing the side of the nickel positive electrode without the part without loaded active material and continues along the winding direction.

9. The zinc-nickel cylindrical battery cell according to claim 8, characterized in that, After winding, the separator facing the side of the nickel positive electrode with the part without loaded active material extends 1 - 3 mm along the long side direction based on the short side of the rectangle of the loaded active material part of the side of the nickel positive electrode with the part without loaded active material and extends along the winding direction; Preferably, the zinc negative electrode facing the side of the nickel positive electrode with the part without loaded active material shortens 1 - 3 mm along the long side direction based on the short side of the rectangle of the separator facing the side of the nickel positive electrode with the part without loaded active material and along the winding direction.

10. A zinc-nickel cylindrical battery cell according to claim 9, characterized in that, The insulating layer is attached to the zinc negative electrode exposed outside the battery cell, neither completely covering the part of the nickel positive electrode without loaded active material nor leaving any exposed part of the zinc negative electrode on the side of the cylindrical battery cell. At the rectangular edge of the insulating layer in the winding direction, it extends 1 to 5 mm outward based on the short-side edge of the outermost zinc negative electrode. Preferably, the insulating layer includes at least one of polyethylene, polypropylene, and polytetrafluoroethylene.

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