A positive electrode cap, a preparation method of the positive electrode cap and a zinc-nickel cylindrical battery

Abstract

In order to overcome the problem that the positive cap of the zinc-nickel cylindrical battery in the prior art is damaged in the welding process of the positive cap and the tab, and then a side reaction occurs between the positive cap and the zinc negative electrode, a positive cap, a preparation method of the positive cap and a zinc-nickel cylindrical battery thereof are provided.The positive cap comprises a positive cap body, and the positive cap body comprises a bottom plate, and an insulating adhesive layer is arranged on the bottom plate.The insulating adhesive layer comprises insulating adhesive, and the insulating adhesive comprises inorganic additives, and the inorganic additives comprise first inorganic additives, and the first inorganic additives comprise cerium compounds.Cerium ions in the insulating adhesive of the positive cap provided by the application can dissolve in the electrolyte, re-deposit in the damaged area, form a repair barrier for the damaged area of the positive cap, prevent the contact between the positive cap and the zinc negative electrode, reduce the consumption of zinc, fundamentally inhibit the occurrence of the electrochemical corrosion reaction, solve the side reaction between the nickel-zinc cylindrical battery and the zinc negative electrode, and then improve the cycle performance and safety performance of the nickel-zinc cylindrical battery.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, specifically relating to insulating adhesive, a method for preparing the insulating adhesive, and a zinc-nickel cylindrical battery thereof. Background Technology

[0002] In the current battery market, commercially available zinc-nickel cylindrical batteries are widely used in various small electronic devices and portable tools. Currently, most commercially available zinc-nickel cylindrical batteries use nickel-plated steel as the positive electrode cap base plate.

[0003] A significant potential difference exists between nickel / iron metals and the zinc negative electrode, resulting in a highly unstable battery chemistry. During battery use and storage, side reactions such as hydrogen evolution and passivation frequently occur. Hydrogen evolution causes a rapid increase in internal pressure, leading to a rapid decrease in battery capacity. Passivation forms a layer on the electrode surface that hinders electrochemical reactions, significantly reducing charge and discharge efficiency. These combined side reactions drastically shorten the battery's cycle life, failing to meet long-term user needs. Furthermore, the battery's capacity recovery performance after long-term storage is extremely poor, severely impacting its practicality and market competitiveness.

[0004] To address the aforementioned issues, researchers in this field have implemented numerous improvement measures, such as using pure copper, tin-plated copper base plates, or tin-plated positive electrode cap base plates. While these measures have improved the side reactions, their application is limited due to the high cost of copper. Therefore, tin plating of the positive electrode cap base plate has become a superior measure. However, during the tab welding process, the large current can damage the tin plating layer of the base plate, which also fails to fundamentally solve the problem. Summary of the Invention

[0005] To address the problem in existing zinc-nickel cylindrical batteries where the welding process between the positive electrode cap and the tab damages the positive electrode cap, leading to side reactions between the positive electrode cap and the zinc negative electrode, this paper provides a positive electrode cap, a method for preparing the positive electrode cap, and a zinc-nickel cylindrical battery thereof.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] On one hand, the present invention provides a positive electrode cap, including a positive electrode cap body, the positive electrode cap body including a base plate, and an insulating adhesive layer disposed on the base plate;

[0008] The insulating adhesive layer includes an insulating adhesive, the insulating adhesive includes inorganic additives, the inorganic additives include a first inorganic additive, and the first inorganic additive includes cerium compounds.

[0009] Optionally, the cerium compounds include one or more of cerium oxides, cerium fluorides, or cerium chlorides;

[0010] The cerium oxide includes one or more of Ce2O3 and CeO2; and / or, the cerium fluoride includes one or more of CeF3 and CeF4; and / or, the cerium chloride includes one or more of CeCl3, CeCl4, CeCl3·7H2O, and K2CeCl5.

[0011] Optionally, the inorganic additive further includes a second inorganic additive, which includes one or more of silicon oxide, antimony oxide, wollastonite, asbestos, mica, and bismuth sulfate.

[0012] Optionally, the mass ratio of the first inorganic additive to the second inorganic additive is 1:10 to 1:1.

[0013] Optionally, the insulating adhesive further includes a leveling agent and an organic adhesive, wherein the leveling agent includes one or more of polydimethylsiloxane, silicone oil, and polyacrylic acid; and / or, the organic adhesive includes one or more of asphalt and natural rubber.

[0014] Optionally, the insulating adhesive comprises the following components by weight:

[0015] 3-8 parts leveling agent

[0016] 85-92 parts of organic glue

[0017] Inorganic additives 2-6 parts.

[0018] Optionally, the thickness of the insulating adhesive layer is 100-300 μm.

[0019] Optionally, a tin-plated layer is also provided on the base plate, and the tin-plated layer is disposed between the insulating adhesive layer and the base plate.

[0020] Optionally, the thickness of the tin plating layer is 3-5 μm.

[0021] Optionally, the method for preparing the positive electrode cap includes the following operations:

[0022] Take the positive electrode cap body and tin-plat it on the surface of its base plate;

[0023] The leveling agent, organic adhesive, and inorganic additives are mixed and thoroughly mixed to obtain an insulating adhesive.

[0024] The insulating adhesive is applied to the tin-plated layer surface of the positive electrode cap base plate and dried to obtain the positive electrode cap.

[0025] On the other hand, the present invention provides a nickel-zinc cylindrical battery, comprising a positive electrode, a negative electrode, an electrolyte, a positive electrode tab, and a positive electrode cap or a positive electrode cap prepared by the method for preparing the positive electrode cap.

[0026] The beneficial effects of this application are as follows:

[0027] The positive electrode cap provided in this application includes a positive electrode cap body, which includes a base plate. An insulating adhesive layer is disposed on the base plate. The insulating adhesive layer includes insulating adhesive, and the first additive in the insulating adhesive includes a cerium compound. In a nickel-zinc battery system, the cerium ions in the cerium compound can function through a dissolution-redeposition process. During the tab welding process, the tin plating layer of the positive electrode cap base plate may be damaged by the current, potentially causing the base plate to be exposed, leading to contact between the positive electrode cap and the electrolyte, affecting the performance of the nickel-zinc battery. In this case, the cerium ions in the insulating adhesive of this application... It dissolves in the electrolyte and redeposits in the damaged area, forming a new protective layer. This forms a repair barrier for the damaged area of ​​the positive electrode cap, further preventing contact between the positive electrode cap and the zinc negative electrode, thus reducing zinc consumption. In addition, the insulating adhesive layer, as a whole, has insulating properties, which can prevent the transfer of electrons between the positive electrode cap and the zinc negative electrode, preventing any potential micro-batteries from forming a complete circuit. This fundamentally inhibits the occurrence of electrochemical corrosion reactions, solves the side reactions between the nickel-zinc cylindrical battery and the zinc negative electrode, and thus improves the cycle performance and safety performance of the nickel-zinc cylindrical battery. Detailed Implementation

[0028] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] This invention provides a positive electrode cap, including a positive electrode cap body, the positive electrode cap body including a base plate, and an insulating adhesive layer disposed on the base plate;

[0030] The insulating adhesive layer includes an insulating adhesive, the insulating adhesive includes inorganic additives, the inorganic additives include a first inorganic additive, and the first inorganic additive includes cerium compounds.

[0031] Specifically, the positive electrode cap provided in this application includes a positive electrode cap body, the positive electrode cap body including a base plate, the base plate being provided with an insulating adhesive layer, the insulating adhesive layer including insulating adhesive, and the first additive in the insulating adhesive including a cerium compound. In a nickel-zinc battery system, the cerium ions in the cerium compound can play a role through a dissolution-redeposition process. During the tab welding process, the current may damage the tin plating layer of the positive electrode cap base plate, which may cause the base plate to be exposed, leading to contact between the positive electrode cap and the electrolyte, affecting the performance of the nickel-zinc battery. At this time, the cerium in the insulating adhesive of this application... Ions dissolve in the electrolyte and redeposit in the damaged area, forming a new protective layer. This creates a repair barrier for the damaged area of ​​the positive electrode cap, further preventing contact between the positive electrode cap and the zinc negative electrode and reducing zinc consumption. In addition, the insulating adhesive layer, as a whole, has insulating properties, preventing the transfer of electrons between the positive electrode cap and the zinc negative electrode. This prevents any potential micro-batteries from forming a complete circuit, fundamentally inhibiting electrochemical corrosion reactions, resolving side reactions between the nickel-zinc cylindrical battery and the zinc negative electrode, and thus improving the cycle performance and safety performance of the nickel-zinc cylindrical battery.

[0032] In some embodiments, the cerium compounds include one or more of cerium oxides, cerium fluorides, or cerium chlorides;

[0033] The cerium oxide includes one or more of Ce2O3 and CeO2; and / or, the cerium fluoride includes one or more of CeF3 and CeF4; and / or, the cerium chloride includes one or more of CeCl3, CeCl4, CeCl3·7H2O, and K2CeCl5.

[0034] Specifically, in the nickel-zinc battery system, cerium oxide can undergo a valence state change under certain conditions, achieving dissolution-redeposition through the valence state change of cerium ions; when the insulating adhesive layer is damaged and the electrolyte around the zinc negative electrode comes into contact with the exposed positive electrode cap bottom plate, Ce³⁺ can lose electrons in the damaged area and be re-oxidized to Ce. 4 ⁺, and deposited at the damaged site, forming a new protective layer, preventing further reaction between the positive electrode cap bottom plate and the zinc negative electrode, reducing zinc consumption, and playing a self-repairing and protective role.

[0035] Within the battery's internal environment, cerium ions from cerium fluorides can also participate in the dissolution-redeposition process. Some fluoride ions may detach from the electrolyte, allowing cerium ions to enter the electrolyte in some form. When these cerium ions encounter damaged areas of the insulating layer, they react with surrounding substances, redepositing to form new cerium fluoride or other cerium-containing compounds. This forms a protective layer in the damaged area, preventing micro-battery reactions and thus reducing corrosion of the zinc anode.

[0036] In the electrolyte environment of nickel-zinc batteries, cerium chloride will ionize to produce cerium ions and chloride ions. When the insulating adhesive layer is damaged, the cerium ions can diffuse with the electrolyte in the damaged area and redeposit at the damaged site. Moreover, the dissolution-redeposition process of cerium chloride is relatively easy to carry out, which can quickly repair and protect the damage to the insulating adhesive layer to a certain extent.

[0037] In some embodiments, the inorganic additive further includes a second inorganic additive, which includes one or more of silicon oxide, antimony oxide, wollastonite, asbestos, mica, and bismuth sulfate.

[0038] Specifically, the wollastonite, asbestos, and mica in the second inorganic additive contain multiple elements such as magnesium, aluminum, calcium, and lithium. The abundant trace metals have a more stable electrochemical potential compared to zinc, the active material of the nickel-zinc battery anode. Under acidic and alkaline conditions, the reaction is slow or even non-existent. Under extreme conditions of high current and high voltage, magnesium, aluminum, and lithium are preferentially sacrificed, which helps to reduce the consumption of the anode active material and plays a role in stabilizing chemical activity. In addition, the above-mentioned elements are also one of the components in the anode system of the nickel-zinc battery described in this application. Using the above-mentioned substances as the second inorganic additive for the insulating adhesive layer reduces the introduction of components into the system.

[0039] In some embodiments, the mass ratio of the first inorganic additive to the second inorganic additive is 1:10 to 1:1.

[0040] Specifically, this application sets the mass ratio of the first inorganic additive and the second inorganic additive within the above-mentioned range, which can better leverage the synergistic effect between the two. The first inorganic additive is effective in forming a protective layer, while the second inorganic additive is beneficial to improving the stability of the battery. By adjusting the mass ratio, the two additives can better exert their overall protective and stabilizing effects, effectively blocking the micro-battery path and reducing the corrosion of the zinc anode.

[0041] A suitable ratio can make the dissolution-redeposition process of cerium ions smoother and more efficient, allowing the components in the first and second inorganic additives to play a timely and effective role during battery operation, thereby more quickly preventing the reaction between the positive electrode cap and the zinc negative electrode and reducing zinc consumption.

[0042] In some embodiments, the insulating adhesive further includes a leveling agent and an organic adhesive, wherein the leveling agent includes one or more of polydimethylsiloxane, silicone oil, and polyacrylic acid; and / or, the organic adhesive includes one or more of asphalt and natural rubber.

[0043] Specifically, the low surface tension and leveling properties of the leveling agent enable the insulating adhesive to spread better during the coating process, fill in tiny bumps and depressions, and make the surface of the insulating adhesive layer smoother. This helps the insulating adhesive to be evenly distributed on the positive electrode cap base plate, ensuring a consistent thickness of the insulating adhesive layer, making the insulation performance and protection effect more stable, and effectively blocking the path for the positive electrode cap substrate and the cell to form a micro battery.

[0044] Organic adhesives can firmly bond inorganic additives, leveling agents, and other components together to form a stable insulating adhesive system. For example, the high elasticity and flexibility of natural rubber enable the insulating adhesive layer to withstand the volume changes and mechanical vibrations of the battery during charging and discharging, making it less prone to cracking or damage. This maintains good coverage and insulation of the positive electrode cap. In addition, natural rubber has good insulation properties, which work synergistically with other components to further improve the overall insulation effect of the insulating adhesive layer, block the electron conduction path between the positive electrode cap bottom plate and zinc, and reduce the corrosion of the zinc negative electrode.

[0045] In some embodiments, the insulating adhesive comprises the following components by weight:

[0046] 3-8 parts leveling agent

[0047] 85-92 parts of organic glue

[0048] Inorganic additives 2-6 parts.

[0049] In some embodiments, the thickness of the insulating adhesive layer is 100-300 μm.

[0050] Specifically, controlling the thickness of the insulating adhesive layer within the range of 100-300μm helps to make the electric field distribution within the insulating adhesive layer more uniform. If the adhesive layer is too thin, the electric field may be concentrated in some weak areas, causing partial discharge or insulation breakdown. A thickness of 100-300μm can make the electric field relatively uniformly distributed within the adhesive layer, reducing the possibility of insulation failure caused by uneven electric field.

[0051] The 100-300μm thickness gives the insulating adhesive layer a certain mechanical strength and toughness, enabling it to withstand various mechanical stresses during battery production, assembly, and use. It can effectively protect the solder joints of the positive electrode cap and the base plate, preventing damage from external mechanical forces and ensuring the integrity of the battery structure.

[0052] In some embodiments, a tin-plated layer is further provided on the base plate, the tin-plated layer being disposed between the insulating adhesive layer and the base plate.

[0053] Specifically, the tin plating layer and the insulating adhesive layer form a dual protective structure. The tin plating layer initially blocks the contact between the base plate and the outside world, while the insulating adhesive layer further blocks the pathway of the micro battery from a physical and chemical perspective. When the tin plating layer is locally damaged, the components in the insulating adhesive layer (such as inorganic additives containing cerium compounds) can further protect the base plate through self-repair and other functions, preventing electrochemical corrosion reactions between the positive electrode cap base plate and the zinc negative electrode. The two work together to greatly improve the protection effect on the zinc negative electrode.

[0054] Tin plating can improve the adhesion between the insulating adhesive layer and the base plate. When the base plate of the positive electrode cap is directly bonded to the insulating adhesive layer, there may be insufficient adhesion. However, the surface properties of the tin plating layer are more suitable for bonding with the insulating adhesive layer, which can make the insulating adhesive layer adhere more firmly to the base plate. During the use of the battery, it can also ensure that the insulating adhesive layer is firmly attached and does not fall off, and can continue to play its role in insulation and protection.

[0055] In some embodiments, the thickness of the tin plating layer is 3-5 μm.

[0056] Specifically, the tin plating layer within this range can form an effective barrier layer between the base plate and the external environment, effectively preventing the metal material of the base plate from directly contacting substances such as air, moisture, and electrolyte inside the battery, thereby reducing the risk of oxidation and corrosion, extending the service life of the base plate, and ensuring the stability of the battery structure.

[0057] During the welding process, the 3-5μm tin plating layer can melt well at the welding temperature and form a good bond with the welding material, ensuring a good electrical connection between the electrode and the base plate and ensuring stable charging and discharging performance of the battery.

[0058] In some embodiments, the method for preparing the positive electrode cap includes the following operations:

[0059] Take the positive electrode cap body and tin-plat it on the surface of its base plate;

[0060] The leveling agent, organic adhesive, and inorganic additives are mixed and thoroughly mixed to obtain an insulating adhesive.

[0061] The insulating adhesive is applied to the tin-plated layer surface of the positive electrode cap base plate and dried to obtain the positive electrode cap.

[0062] Another embodiment of the present invention provides a nickel-zinc cylindrical battery, comprising a positive electrode, a negative electrode, an electrolyte, a positive electrode tab, and a positive electrode cap or a positive electrode cap prepared by the method for preparing the positive electrode cap.

[0063] Specifically, in this nickel-zinc cylindrical battery, the positive electrode undergoes an oxidation reaction and releases electrons, while the negative electrode accepts electrons and undergoes a reduction reaction. The positive electrode tab connects the positive electrode and the positive electrode cap for electron transport. The insulating adhesive layer on the bottom plate of the positive electrode cap described in this application includes cerium compounds. In the nickel-zinc battery system, the cerium ions in the cerium compounds can play a role through a dissolution-redeposition process. During the tab welding process, the tin plating layer of the bottom plate of the positive electrode cap may be damaged by the current, which may cause the bottom plate to be exposed, leading to contact between the positive electrode cap and the electrolyte and affecting the performance of the nickel-zinc battery. At this time, the cerium ions in the insulating adhesive of this application will dissolve in the electrolyte and redeposit in the damaged area to form a new protective layer, forming a repair barrier for the damaged area of ​​the positive electrode cap. This further prevents contact between the positive electrode cap and the zinc negative electrode, preventing the formation of micro-cells between the positive electrode cap substrate and the zinc of the negative electrode, thus accelerating zinc corrosion and improving the stability, safety, and service life of the battery.

[0064] The present invention will be further illustrated by the following examples.

[0065] Example 1

[0066] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including the following steps:

[0067] Preparation of the positive electrode cap:

[0068] Take 5 parts of leveling agent polydimethylsiloxane, 90 parts of organic adhesive asphalt and 5 parts of inorganic additives (first additive CeF3, second additive wollastonite, CeF3:wollastonite = 1:2), mix them to obtain insulating adhesive;

[0069] Take the positive electrode cap body and plate tin on its base plate to obtain a positive electrode cap body with a tin plating layer. The thickness of the tin plating layer is 3μm.

[0070] The insulating adhesive is applied to the surface of the tin-plated layer of the base plate with a thickness of 200μm to obtain the positive electrode cap.

[0071] Preparation of positive electrode:

[0072] Take Ni(OH)2, ZnO, CoO, Ni powder, Ca(OH)2, Y2O3, Yb2O3, graphite, CMC, and PTFE, mix them evenly in a ratio of 86.5:1:3:2:1:2:2:1:0.5:3, coat the mixture onto the positive electrode current collector, and then roll, soften, and cut it to obtain the positive electrode.

[0073] Preparation of negative electrode:

[0074] Take 1% conductive material, 0.3% thickener, and 1% dispersant, mix them well, then add 0.02% In2O3, 0.08% Bi2O3, and 3% Al2O3, mix again, then add 58% ZnO, 30% Zn, and 3.6% binder, stir evenly, and coat it on the negative electrode current collector. After rolling, softening, and cutting, the negative electrode is obtained.

[0075] Preparation of electrolyte:

[0076] The electrolyte in this embodiment consists of 80% (5-5.5 mol / L) KOH, 2% (5 mol / L) ZnO, 10% silica sol, and 3-5% disodium hydrogen phosphate.

[0077] Example 2

[0078] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0079] In the preparation of insulating adhesive, the mass ratio of the first additive to the second additive is 1:1.

[0080] Example 3

[0081] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0082] In the preparation of insulating adhesive, the mass ratio of the first additive to the second additive is 1:3.

[0083] Example 4

[0084] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0085] In the preparation of insulating adhesive, the first additive is cerium oxide (Ce2O3), and the second additive is silicon oxide.

[0086] Example 5

[0087] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0088] In the preparation of insulating adhesive, the first additive is cerium chloride (CeCl3), and the second additive is antimony oxide.

[0089] Example 6

[0090] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0091] In the preparation of the insulating adhesive, the first additive is cerium chloride (CeCl3) and cerium fluoride (CeF3), with CeCl3:CeF3=1:1, and the second additive is wollastonite.

[0092] Example 7

[0093] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0094] In the preparation of the insulating adhesive, the first additive is cerium chloride (CeCl3), cerium fluoride (CeF3) and cerium oxide (Ce2O3), with CeCl3:CeF3:Ce2O3=1:1:1, and the second additive is wollastonite.

[0095] Example 8

[0096] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0097] The coating thickness of the insulating adhesive is 100μm.

[0098] Example 9

[0099] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0100] The coating thickness of the insulating adhesive is 300μm.

[0101] Example 10

[0102] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0103] The thickness of the tin plating layer is 4μm.

[0104] Example 11

[0105] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0106] The thickness of the tin plating layer is 5μm.

[0107] Example 12

[0108] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0109] In the preparation of the insulating adhesive, the leveling agent is 8 parts, the organic adhesive is 87 parts, and the inorganic additive is 5 parts.

[0110] Example 13

[0111] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0112] In the preparation of the insulating adhesive, the leveling agent is 5 parts, the organic adhesive is 92 parts, and the inorganic additive is 3 parts.

[0113] Example 14

[0114] This embodiment illustrates a method for preparing a positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, with the following differences:

[0115] In the preparation of the insulating adhesive, the leveling agent is 3 parts, the organic adhesive is 92 parts, and the inorganic additive is 5 parts.

[0116] Comparative Example 1

[0117] This comparative example is used to illustrate the preparation method of the positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, except that:

[0118] No first additive was added during the preparation of the insulating adhesive.

[0119] Comparative Example 2

[0120] This comparative example is used to illustrate the preparation method of the positive electrode cap and its zinc-nickel cylindrical battery disclosed in this invention, including most of the operations in Example 1, except that:

[0121] Potassium fluoride is selected as the first additive in the preparation of insulating adhesive.

[0122] Performance testing

[0123] The following performance tests were performed on Examples 1-14 and Comparative Examples 1-2 prepared above:

[0124] Supplement the corresponding test methods and test steps.

[0125] Cycle life

[0126] At 25°C, the zinc-nickel batteries prepared in each embodiment and comparative example were charged at 1C to 1.9V and then charged at a constant voltage of 1.9V to the cutoff current of 13.5mA. They were then discharged at 1C to 1.3V. The charging and discharging were repeated until the battery capacity was reduced to 60% of the first charge. The number of charge and discharge cycles was recorded.

[0127] 5C high-rate performance

[0128] At 25°C, the zinc-nickel batteries prepared in each embodiment and comparative example were charged at 0.2C to 1.9V, then charged at a constant voltage of 1.9V to a cutoff current of 13.5mA, and discharged at 0.2C to 1.3V. The 0.2C capacity was recorded. The zinc-nickel batteries prepared in each embodiment and comparative example were then charged at 0.2C to 1.9V, then charged at a constant voltage of 1.9V to a cutoff current of 13.5mA, and discharged at 5C to 1.3V. The 5C high-rate discharge capacity percentage = 5C capacity / 0.2C capacity * 100%

[0129] High-temperature cycling capacity retention

[0130] (1) Under 25℃ conditions, charge the battery fully using a constant current and constant voltage charging method, charge at 0.2C to 1.9V, and then charge at 1.9V constant voltage until the cutoff current is 13.5mA, then end the charging process.

[0131] (2) Store a fully charged battery in a 60°C oven for 28 days.

[0132] (3) After storage, discharge to 1.3V at 0.2C, then charge using the same charging method as (1), let stand for 10 minutes, then discharge to 1.3V at 0.2C again, and repeat the above charging and discharging steps 3 times.

[0133] The test results are entered into Table 1.

[0134] Table 1

[0135]

[0136] As can be seen from the test results in Table 1, the cycle life of Examples 1-14 is 220 cycles or more, the cycle life of Comparative Example 1 is 210 cycles, and the cycle life of Comparative Example 2 is 200 cycles. It can be seen that the cycle life of the examples with the first inorganic additive containing cerium compounds is generally higher than that of Comparative Example 1 without the first additive, and Comparative Example 2 using other additives (potassium fluoride) as the first additive. Among them, the cycle life of Example 7 reaches 300 cycles. This shows that the first inorganic additive containing cerium compounds can significantly improve the battery cycle life. This is because cerium ions can form a repair barrier through dissolution-redeposition during battery use, reducing the contact between the positive electrode cap and the zinc negative electrode, suppressing side reactions, and thus extending the number of charge-discharge cycles of the battery.

[0137] The 5C high-rate performance of Examples 1-14 is between 60% and 85%, while that of Comparative Example 1 is 58% and that of Comparative Example 2 is 55%. The comparison shows that the high-rate performance of the Examples is generally better than that of the Comparative Examples. This indicates that the self-healing process involving cerium compounds can stabilize the internal structure and reaction of the battery, so that the battery can maintain good performance even when discharged at high rates, which is beneficial to ensuring the use of the battery in high-power scenarios.

[0138] The SOC of Examples 1-14 ranged from 47.3% to 55.1%, and the SOH ranged from 89.6% to 95.2%. The SOC of Comparative Examples 1-2 were 46.2% and 45.7%, and the SOH were 88.2% and 87.4%, respectively. The comparison shows that the storage performance of Examples 1-14 was significantly higher than that of Comparative Examples 1-2. This indicates that the cerium-containing insulating adhesive plays a role in the storage process by cerium ions dissolving and redepositing themselves, repairing the damaged areas of the positive electrode cap, maintaining the stability of the internal structure and performance of the battery, reducing the negative impact of storage on battery performance, and effectively improving the battery's performance retention capability after storage.

[0139] The internal resistance of the batteries in Examples 1-14 is between 20.1-31.4 mΩ, compared to 32.9 mΩ in Comparative Example 1 and 33.6 mΩ in Comparative Example 2. The internal resistance of the batteries in the examples is relatively low because the dual protective structure of the insulating adhesive layer and the tin plating layer effectively reduces the side reactions inside the battery, lowers the internal resistance of the battery, and makes the energy loss of the battery during charging and discharging less, thereby improving the charging and discharging efficiency and overall performance of the battery.

[0140] Examples 1, 10, and 11 have tin plating layers of different thicknesses. When the tin plating layer thickness increases from 3 μm to 4 μm, the cycle life remains unchanged. When it increases to 5 μm, the cycle life decreases slightly. It is speculated that the excessively thick tin plating layer may affect the stability of the internal structure of the battery, resulting in a slight decrease in cycle life. The 5C high-rate performance test results of Examples 1, 10, and 11 show that a thicker tin plating layer may hinder electron conduction and ion diffusion inside the battery, affecting the battery's reaction rate during high-current discharge. A thinner tin plating layer (3 μm) is more conducive to the electrochemical reaction inside the battery under high-rate discharge conditions. In addition, as the tin plating layer thickness increases, the storage performance gradually decreases. This means that a thicker tin plating layer may not be able to effectively prevent side reactions inside the battery during battery storage, or the interaction between the tin plating layer and the insulating layer may change, affecting the overall chemical stability of the battery and thus reducing storage performance.

[0141] As shown in Examples 12-14, the cycle life of Example 12 is 250 cycles, while that of Examples 13 and 14 is 240 cycles. The data shows that the cycle life first increases and then decreases with the increase of leveling agent (Examples 14-12). The cycle life also first increases and then decreases when the organic adhesive is reduced from 92 parts to 87 parts (Examples 13-12). This indicates that appropriate amounts of leveling agent and organic adhesive help to improve the cycle life. Leveling agent can make the insulating adhesive spread better, ensure stable insulation performance, and extend the cycle life. In addition, organic adhesive can bind the components and provide good insulation and protection.

[0142] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nickel-zinc cylindrical battery, characterized in that, It includes a positive electrode, a negative electrode, an electrolyte, a positive electrode tab, and a positive electrode cap. The positive electrode tab is connected to the positive electrode and the positive electrode cap, and the positive electrode tab and the positive electrode cap are welded together. The positive electrode cap includes a positive electrode cap body, the positive electrode cap body includes a base plate, and an insulating adhesive layer is provided on the base plate; The insulating adhesive layer includes an insulating adhesive, the insulating adhesive includes an inorganic additive, the inorganic additive includes a first inorganic additive, and the first inorganic additive includes a cerium compound; The inorganic additive also includes a second inorganic additive, which includes one or more of silicon dioxide, antimony oxide, wollastonite, asbestos, mica, and bismuth sulfate. The mass ratio of the first inorganic additive to the second inorganic additive is 1:10 to 1:1; The insulating adhesive comprises the following components by weight: 3-8 parts leveling agent; 85-92 parts of organic adhesive; Inorganic additives 2-6 parts.

2. The nickel-zinc cylindrical battery according to claim 1, characterized in that, The cerium compounds include one or more of cerium oxides, cerium fluorides, or cerium chlorides; The cerium oxide includes one or more of Ce2O3 and CeO2; and / or, the cerium fluoride includes one or more of CeF3 and CeF4; and / or, the cerium chloride includes one or more of CeCl3, CeCl4, CeCl3·7H2O, and K2CeCl5.

3. The nickel-zinc cylindrical battery according to claim 1, characterized in that, The leveling agent includes one or more of polydimethylsiloxane, silicone oil, and polyacrylic acid; and / or, the organic adhesive includes one or more of asphalt and natural rubber.

4. The nickel-zinc cylindrical battery according to claim 1, characterized in that, The thickness of the insulating adhesive layer is 100-300μm.

5. The nickel-zinc cylindrical battery according to claim 1, characterized in that, The base plate is also provided with a tin-plated layer, which is disposed between the insulating adhesive layer and the base plate.

6. The nickel-zinc cylindrical battery according to claim 5, characterized in that, The thickness of the tin plating layer is 3-5 μm.

7. The nickel-zinc cylindrical battery according to any one of claims 1-6, characterized in that, The method for preparing the positive electrode cap includes the following operations: Take the positive electrode cap body and tin-plat it on the surface of its base plate; The leveling agent, organic adhesive, and inorganic additives are mixed and thoroughly mixed to obtain an insulating adhesive. The insulating adhesive is applied to the tin-plated layer surface of the positive electrode cap base plate and dried to obtain the positive electrode cap.

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