Negative tab, preparation method thereof, negative tab sheet, soft package battery and vehicle

Abstract

The application provides a negative tab, a preparation method thereof, a negative tab sheet, a soft package battery and a vehicle. The negative tab comprises a substrate; and a corrosion-resistant layer arranged on at least one side of the substrate, wherein the material forming the corrosion-resistant layer comprises nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer is less than or equal to 0.3 microns. Thus, the electrolyte resistance of the negative tab is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of batteries, in particular, to a negative tab, a preparation method thereof, a negative tab sheet, a soft package battery and a vehicle. BACKGROUND

[0002] The negative tab is prone to corrosion in the electrolyte environment, leading to battery failure, therefore, special treatment needs to be performed on the surface of the negative tab, for example, a plating layer can be formed on the surface of the negative tab base to improve the corrosion resistance of the negative tab. The corrosion resistance of the negative tab in the related art is limited. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to provide a negative tab, a preparation method thereof, a soft package battery and a vehicle. The thickness of the corrosion-resistant layer on the surface of the negative tab is uniform, which can improve the bonding ability of the corrosion-resistant layer and the base and improve the electrolyte resistance of the negative tab.

[0004] The present application provides a negative tab, which includes a base; a corrosion-resistant layer, the corrosion-resistant layer is arranged on at least one side of the base, the material forming the corrosion-resistant layer includes nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer is less than or equal to 0.3 μm.

[0005] The negative tab provided by the present application includes nickel phosphide in the corrosion-resistant layer, by making the thickness fluctuation of the corrosion-resistant layer less than or equal to 0.3 μm, the uniformity of the thickness distribution of the corrosion-resistant layer on the negative tab is improved, the risk of local shedding of the corrosion-resistant layer due to uneven thickness is reduced, the bonding force inside the corrosion-resistant layer is improved, and the electrolyte resistance of the whole negative tab is improved.

[0006] The negative tab provided by the present application also has the following additional technical features:

[0007] According to some embodiments of the present application, the thickness of the corrosion-resistant layer is 0.6 μm-2.4 μm. In this way, the thickness of the corrosion-resistant layer is increased, and the electrolyte resistance of the negative tab is improved.

[0008] According to some embodiments of the present application, the corrosion-resistant layer is arranged on at least one side of the base in the thickness direction. In this way, the electrolyte resistance of the negative tab is improved.

[0009] According to some embodiments of the present application, the material forming the base includes copper.

[0010] The second aspect of the present application provides a method for preparing a negative tab, the method comprising: forming a corrosion-resistant layer on at least one side of a substrate by using an alternating current power source, the material forming the corrosion-resistant layer comprising nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer being less than or equal to 0.3 μm. Thus, the thickness of the corrosion-resistant layer on the negative tab prepared by the method is more uniform, and the corrosion-resistant layer has stronger electrolyte resistance.

[0011] According to some embodiments of the present application, the method comprises placing a metal nickel and copper strip in an electroplating solution comprising a nickel salt and a phosphorus salt, and forming the corrosion-resistant layer on at least one side of the substrate under the action of the alternating current power source. Thus, the nickel phosphide layer as the corrosion-resistant layer can reduce the probability of corrosion of the substrate and improve the electrolyte resistance of the negative tab.

[0012] According to some embodiments of the present application, the positive voltage of the alternating current power source lasts for t1, the reverse voltage lasts for t2, and t1:t2=(2-10):1 is satisfied. Thus, the uniformity of the thickness of the corrosion-resistant layer is improved.

[0013] According to some embodiments of the present application, the current density of the alternating current power source is 2 A / dm 2 -5 A / dm 2 . Thus, the rate of electroplating to form the corrosion-resistant layer is improved, and the thickness of the corrosion-resistant layer is improved.

[0014] According to some embodiments of the present application, the method satisfies at least one of the following conditions: the mass concentration of the nickel salt in the electroplating solution is 60 g / L-150 g / L; the mass concentration of the phosphorus salt in the electroplating solution is 10 g / L-30 g / L; the pH of the electroplating solution is 2-5; and the temperature of the electroplating solution is 40℃-70℃. Thus, the rate of electroplating to form the corrosion-resistant layer is improved, the thickness of the corrosion-resistant layer is improved, and the electrolyte resistance of the negative tab is improved.

[0015] According to some embodiments of the present application, the alternating current power source is a pulse alternating current power source.

[0016] According to some embodiments of the present application, the method further comprises a process of soaking the substrate on which the corrosion-resistant layer is formed in a passivation solution. Thus, a protective group is formed on the surface of the corrosion-resistant layer away from the substrate.

[0017] The third aspect of the present application provides a negative tab, comprising the negative tab provided by the first aspect of the present application or the negative tab prepared by the method provided by the second aspect of the present application.

[0018] The fourth aspect of the present application provides a soft package battery, comprising the negative tab provided by the third aspect of the present application.

[0019] The fifth aspect of the present application provides a vehicle comprising the pouch battery of the fourth aspect of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the description of the embodiments, given by reference to the following figures, wherein:

[0021] Figure 1 A schematic view of a negative tab structure of an embodiment of the present application is shown.

[0022] Figure 2 A schematic view of electroless plating in the related art is shown.

[0023] Figure 3 A schematic view of electroplating in the related art is shown.

[0024] Figure 4 A schematic view of electroplating of an embodiment of the present application is shown.

[0025] REFERENCE NUMERALS

[0026] 1: negative tab; 11: substrate; 12: first corrosion-resistant layer; 13: second corrosion-resistant layer. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described in detail below. The embodiments described below are exemplary only, and are not to be understood as limiting the present application. Where specific techniques or conditions are not described, techniques or conditions described in the literature are used or product specifications are followed. Where the manufacturer of the reagent or instrument is not indicated, conventional products available from commercial vendors are used.

[0028] REFERENCE Figure 2 In the related art, electroless plating is used to form a corrosion-resistant layer on the surface of a substrate, and the plating layer is formed at a slow speed, and the corrosion-resistant layer formed is relatively thin, which will affect the electrolyte resistance of the negative tab to some extent; with reference to Figure 3 Electroplating can also be used to form a corrosion-resistant layer on the surface of a substrate. Due to the unevenness of the substrate surface, preferential deposition occurs at the protruding position during electroplating deposition, resulting in uneven thickness distribution of the corrosion-resistant layer, and poor adhesion of the corrosion-resistant layer on the substrate surface. Although this method improves the deposition speed of the plating layer and reduces the time cost, it reduces the electrolyte resistance of the negative tab.

[0029] The first aspect of the present application provides a negative tab, comprising: a substrate; a corrosion-resistant layer, the corrosion-resistant layer being provided on at least one side of the substrate, the material forming the corrosion-resistant layer comprising nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer being less than or equal to 0.3 μm.

[0030] The negative tab provided by the present application, the corrosion-resistant layer includes nickel phosphide, by making the thickness fluctuation of the corrosion-resistant layer less than or equal to 0.3 μm, the uniformity of the thickness distribution of the corrosion-resistant layer on the negative tab is improved, the risk of the corrosion-resistant layer falling off locally due to uneven thickness is reduced, the bonding force inside the corrosion-resistant layer is improved, and the electrolyte resistance of the whole negative tab is improved.

[0031] In the present application, the thickness fluctuation of the corrosion-resistant layer refers to the difference between the thickness of the corrosion-resistant layer at different positions of the negative tab and the average thickness of the corrosion-resistant layer.

[0032] According to some embodiments of the present application, the corrosion-resistant layer is arranged on at least one side of the thickness direction of the substrate. Referring to Figure 1 The negative tab 1 includes a substrate 11, a first corrosion-resistant layer 12 is arranged on one surface of the substrate 11, and a second corrosion-resistant layer 13 is arranged on the other surface of the substrate 11, and the first corrosion-resistant layer 12 and the second corrosion-resistant layer 13 both include nickel phosphide.

[0033] According to an embodiment of the present application, the first corrosion-resistant layer 12 and the second corrosion-resistant layer 13 are both nickel phosphide layers.

[0034] According to some embodiments of the present application, the thickness of the corrosion-resistant layer can be 0.6 μm-2.4 μm. For example, it can be 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm or 2.4 μm, etc., or it can be a range composed of any of the above values. In this way, the thickness of the corrosion-resistant layer is increased, the probability of the substrate of the negative tab being corroded by the electrolyte is reduced, and the electrolyte resistance of the negative tab is improved.

[0035] According to some embodiments of the present application, the first corrosion-resistant layer 12 and the second corrosion-resistant layer 13 are both nickel phosphide layers, the thickness of the first corrosion-resistant layer 12 and the second corrosion-resistant layer 13 is independently 0.6 μm-2.4 μm respectively, and the thickness fluctuation of the first corrosion-resistant layer 12 and the second corrosion-resistant layer 13 is less than or equal to 0.3 μm. In this way, nickel phosphide is used as the corrosion-resistant layer, the corrosion of the substrate 11 by the electrolyte is reduced, and the electrolyte resistance of the negative tab 1 is improved.

[0036] According to some embodiments of the present application, the material forming the substrate 11 includes copper.

[0037] According to a specific embodiment of the present application, the substrate 11 is a copper substrate. By forming a corrosion-resistant layer containing nickel phosphide on at least one side of the copper substrate 11, the corrosion of the copper substrate by the electrolyte is reduced, and the electrolyte resistance of the negative tab is improved.

[0038] According to some embodiments of the present application, the corrosion-resistant layer can further include a brightener to improve the brightness of the corrosion-resistant layer.

[0039] A second aspect of the present application provides a method for preparing a negative tab, referring to Figure 4 The method includes forming a corrosion-resistant layer on at least one side of the substrate using an alternating current power source, the material forming the corrosion-resistant layer including nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer being less than or equal to 0.3 μm. Thus, the electroplating using the alternating current power source causes the plating layer to be preferentially deposited at protruding positions even if the surface of the substrate is uneven, but the reverse current can reverse the dissolution of the thicker corrosion-resistant layer formed at the protruding positions, preventing the protruding positions from continuously depositing the corrosion-resistant layer to cause uneven thickness distribution, thereby improving the density of the corrosion-resistant layer, improving the uniformity of the thickness distribution of the corrosion-resistant layer on the surface of the substrate, improving the bonding force within the corrosion-resistant layer, and improving the overall electrolyte resistance of the negative tab.

[0040] According to some embodiments of the present application, the method includes placing a metal nickel and copper strip in an electroplating solution including a nickel salt and a phosphorus salt, and forming the corrosion-resistant layer on at least one side of the substrate under the action of the alternating current power source. Thus, a nickel phosphide layer can be formed on the surface of the copper substrate, reducing the probability of corrosion of the copper substrate and improving the electrolyte resistance of the negative tab.

[0041] According to some embodiments of the present application, the thickness of the corrosion-resistant layer can be 0.6 μm-2.4 μm. For example, it can be 0.6 μm, 0.8 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2 μm, 2.2 μm, or 2.4 μm, etc., or a range formed by any of the above values. Thus, the thickness of the corrosion-resistant layer is improved, the probability of corrosion of the substrate of the negative tab by the electrolyte is reduced, and the electrolyte resistance of the negative tab is improved.

[0042] According to some embodiments of the present application, the alternating current power source is a pulse alternating current power source.

[0043] According to some embodiments of the present application, the duration of the forward voltage of the alternating current power source is t1, the duration of the reverse voltage is t2, and t1:t2=(2-10):1. For example, it can be 2:1, 3:1, 5:1, 8:1, or 10:1, etc., or a range formed by any of the above values.

[0044] For example, when t1:t2 is 3:1, the forward voltage is applied for 3 s and the reverse voltage is applied for 1 s.

[0045] According to some embodiments of the present application, the current density of the alternating current power source can be 2 A / dm 2 -5 A / dm 2For example, it can be 2A / dm 2 , 3A / dm 2 , 4A / dm 2 or 5A / dm 2 , etc., or can be a range composed of any of the above values. In this way, the plating rate is improved, and the cost is reduced.

[0046] According to some embodiments of the present application, the mass concentration of the nickel salt in the plating solution can be 60g / L-150g / L, for example, it can be 60g / L, 70g / L, 80g / L, 90g / L, 100g / L, 110g / L, 120g / L, 130g / L, 140g / L or 150g / L, etc., or can be a range composed of any of the above values. In this way, the plating rate is improved.

[0047] According to some embodiments of the present application, the mass concentration of the phosphorus salt in the plating solution can be 10g / -30g / L, for example, it can be 10g / L, 15g / L, 20g / L, 25g / L or 30g / L, etc., or can be a range composed of any of the above values. In this way, the plating rate is improved.

[0048] According to some embodiments of the present application, the pH of the plating solution can be 2-5, for example, it can be 2, 3, 4 or 5, etc.

[0049] According to some embodiments of the present application, the temperature of the plating solution is 40℃-70℃. For example, it can be 40℃, 45℃, 50℃, 55℃, 60℃, 65℃ or 70℃, etc., or can be a range composed of any of the above values.

[0050] According to some embodiments of the present application, the method can further include cleaning the copper strip before plating.

[0051] According to some embodiments of the present application, the cleaning includes degreasing the copper strip by ultrasonic wave. Specifically, the frequency of the ultrasonic wave can be 20KHz-40KHz, for example, it can be 20KHz, 24KHz, 28KHz, 32KHz, 36KHz or 40KHz, etc., or can be a range composed of any of the above values. In this way, the cleaning effect is improved.

[0052] According to some embodiments of the present application, the cleaning can further include electrolytic degreasing the copper strip after the degreasing. Specifically, the density of the current during the electrolytic degreasing can be 10mA / dm 2 -100mA / dm 2 , for example, it can be 10mA / dm 2 , 20mA / dm 2 , 30mA / dm2 40 mA / dm 2 50 mA / dm 2 60 mA / dm 2 70 mA / dm 2 80 mA / dm 2 90 mA / dm 2 or 100 mA / dm 2 or can be a range composed of any of the above values.

[0053] According to some embodiments of the present application, the cleaning can further include, after the electrolytic degreasing, pickling the copper strip. Specifically, the copper strip is placed in an acidic solution to remove the oxide layer on the surface of the copper strip. As an example, the acidic solution can be 10% sulfuric acid.

[0054] According to some embodiments of the present application, the cleaning can further include, after the pickling, activating the copper strip. Specifically, the copper strip can be activated by dilute phosphoric acid.

[0055] According to some embodiments of the present application, after forming the nickel phosphide layer on at least one side of the substrate by using the pulsed alternating current, the method can further include a process of immersing the substrate on which the corrosion-resistant layer is formed in a passivation solution to form passivation groups on the surface of the corrosion-resistant layer away from the substrate, further improving the corrosion resistance of the negative tab.

[0056] As an example, the composition of the passivation solution can refer to the composition of the passivation solution commonly used in the art. Specifically, the passivation solution can include phosphoric acid or phosphoric acid compounds, trivalent chromium compounds, zirconium compounds, fluorides, acrylic resin cross-linking agents, auxiliaries, etc.

[0057] According to some embodiments of the present application, after immersing the copper strip on which the nickel phosphide layer is formed in the passivation solution, the copper strip can be cleaned and dried to accelerate the formation of the protective film.

[0058] The third aspect of the present application proposes a negative tab, which includes the negative tab proposed in the first aspect of the present application or the negative tab prepared by the method proposed in the second aspect of the present application.

[0059] According to some embodiments of the present application, the negative tab includes a negative current collector, and the negative tab is welded on the negative current collector.

[0060] The fourth aspect of the present application proposes a soft package battery, which includes the negative tab proposed in the third aspect of the present application.

[0061] The fifth aspect of the present application proposes a vehicle, which includes the soft package battery proposed in the fourth aspect of the present application.

[0062] Embodiments of the present application are described in detail below. The embodiments described below are exemplary only and are not intended to be limiting of the present application. Unless otherwise indicated, technical or scientific terms used in the embodiments have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. Unless otherwise indicated, all reagents or instruments used in the embodiments are commercially available conventional products.

[0063] Example 1

[0064] (1) Ultrasonic degreasing: oil and foreign matter on the surface of the copper strip are removed by small bubbles generated by ultrasonic vibration; the ultrasonic frequency is 30 KHZ.

[0065] (2) Electrolytic degreasing: oil adhered to the surface of the copper strip is removed by the action of electric current; the current density is 50 mA / dm 2 , and the degreasing time is 1 minute.

[0066] (3) Pickling: the copper strip is placed in an acid solution to remove the surface oxide layer; the acid solution is 10% sulfuric acid, and the temperature is 40°C.

[0067] (4) Activation: the copper strip after pickling is placed in a weak acid solution to activate the surface of the copper strip; dilute phosphoric acid is used in the activation process, and the temperature is 40°C.

[0068] (5) Electroplating: the copper strip is placed in a plating solution, and a layer of nickel phosphide is plated on the surface of the copper strip under the action of an externally applied pulsed alternating current; the positive and negative voltage duration is 3:1 (e.g., a positive voltage is applied for 3 seconds, and then a negative voltage is applied for 1 second), the nickel salt in the plating solution is nickel sulfate, the concentration is 90 g / L, the sodium hypophosphite concentration is 15 g / L, the pH value is 4, the current density is 3 A / dm 2 , and the plating solution temperature is 50°C.

[0069] (6) Surface treatment: 3 g of phosphoric acid, 4 g of chromium nitrate, 1 g of zirconium nitrate, 2 g of sodium fluoride, 4 g of acrylic resin, 1 g of crosslinking agent obtained by reacting isocyanate with maleic anhydride, and sodium hydroxide are placed in 100 g of distilled water to form a uniform plating solution, and the copper strip plated with nickel phosphide is placed in the plating solution for surface treatment.

[0070] (7) Cleaning and drying: hot water washing is followed by drying to obtain the negative tab.

[0071] Example 2

[0072] The method for preparing the negative tab is the same as in Example 1, except that the positive and negative voltage duration is 2:1.

[0073] Example 3

[0074] The method for preparing the negative tab is the same as in Example 1, except that the positive and negative voltage duration is 5:1.

[0075] Comparative Example 1

[0076] (1) Ultrasonic degreasing: oil and foreign matter on the surface of the copper strip are removed by small bubbles generated by ultrasonic vibration; the ultrasonic frequency is 30 KHZ.

[0077] (2) Electrolytic degreasing: oil adhered to the surface of the copper strip is removed under the action of electric current; the current density is 50 mA / dm 2 , and the degreasing time is 1 minute.

[0078] (3) Pickling: the copper strip is placed in an acidic solution to remove the surface oxide layer; the acid solution is 10% sulfuric acid, and the temperature is 40°C.

[0079] (4) Activation: the copper strip after pickling is placed in a weak acidic solution to activate the surface of the copper strip; dilute phosphoric acid is used in the activation process, and the temperature is 40°C.

[0080] (5) Chemical plating: the copper strip is placed in a plating solution, the plating solution includes nickel salt which is nickel sulfate, the concentration is 150 g / L, the concentration of sodium hypophosphite is 30 g / L, the pH value is 2, the current density is 4 A / dm 2 , the plating solution temperature is 60°C, and a layer of nickel phosphide is uniformly plated on the surface of the copper strip by using the potential difference between nickel and copper and driving through the plating solution concentration.

[0081] (6) Surface treatment: 3 g of phosphoric acid, 4 g of chromium nitrate, 1 g of zirconium nitrate, 2 g of sodium fluoride, 4 g of acrylic resin, 1 g of crosslinking agent after the reaction of isocyanate and maleic anhydride, and sodium hydroxide are placed in 100 g of distilled water to form a uniform plating solution, and the copper strip plated with nickel phosphide is placed in the plating solution for surface treatment.

[0082] (7) Cleaning and drying: hot water washing is followed by drying to obtain the negative tab.

[0083] Comparative Example 2

[0084] (1) Ultrasonic degreasing: oil and foreign matter on the surface of the copper strip are removed by small bubbles generated by ultrasonic vibration; the ultrasonic frequency is 30 KHZ.

[0085] (2) Electrolytic degreasing: oil adhered to the surface of the copper strip is removed under the action of electric current; the current density is 50 mA / dm 2 , and the degreasing time is 1 minute.

[0086] (3) Pickling: the copper strip is placed in an acidic solution to remove the surface oxide layer; the acid solution is 10% sulfuric acid, and the temperature is 40°C.

[0087] (4) Activation: the copper strip after pickling is placed in a weak acidic solution to activate the surface of the copper strip; dilute phosphoric acid is used in the activation process, and the temperature is 40°C.

[0088] (5) Electroplating: The copper strip is placed in a plating solution, and a layer of phosphorized nickel is plated on the surface of the copper strip under the action of a direct current power supply. The nickel salt in the plating solution is nickel sulfate, the concentration is 120 g / L, the concentration of sodium hypophosphite is 20 g / L, the pH value is 3, the current density is 4 A / dm 2 , and the plating solution temperature is 60°C.

[0089] (6) Surface treatment: 3 g of phosphoric acid, 4 g of chromium nitrate, 1 g of zirconium nitrate, 2 g of sodium fluoride, 4 g of acrylic resin, 1 g of crosslinking agent after the reaction of isocyanate and maleic anhydride, and sodium hydroxide are placed in 100 g of distilled water to form a uniform plating solution. The copper strip plated with phosphorized nickel is placed in the plating solution for surface treatment.

[0090] (7) Cleaning and drying: After hot water washing, drying is performed to obtain the negative tab.

[0091] Performance test

[0092] 1. Coating thickness test

[0093] The Ni metal template is stored in the X-ray thickness gauge, and the coating thickness can be measured. However, this test method is only for reference, and the accuracy is low. The real thickness of the coating can be clearly and intuitively obtained by observing the cross section of the tab using a metallographic microscope.

[0094] 2. Electrolyte resistance test

[0095] The average thickness of the phosphorized nickel layer in the negative tab of each example / contrast example is measured using an X-ray thickness gauge, which is the initial average thickness of the phosphorized nickel layer. An organic solvent is obtained by mixing equal volumes of ethylene carbonate (EC), methyl ethyl carbonate (EMC), and dimethyl carbonate (DMC). Then, lithium hexafluorophosphate is dissolved in the above organic solvent to prepare an electrolyte with a concentration of 1 mol / L. The electrolyte is placed in a beaker, and then the tab is placed in it. The tab is soaked in a 60°C environment for 28 days. The change in coating thickness is observed, and the average thickness of the phosphorized nickel layer after 28 days of soaking is measured using an X-ray thickness gauge.

[0096] 3. Thickness fluctuation test method

[0097] The thickness of ten different points of each example / contrast example negative tab (one negative tab is taken from ten different points) is tested using an X-ray thickness gauge, and the thickness fluctuation of the tab is calculated.

[0098] The test results of Example 1-Example 3, Comparative Example 1, and Comparative Example 2 are shown in Table 1.

[0099] Table 1

[0100]

[0101] The retention rate of the nickel phosphide layer = (the average thickness of the nickel phosphide layer after 28 days of immersion / the initial average thickness of the nickel phosphide layer) x 100%.

[0102] The calculation method of the thickness fluctuation at different positions is: the absolute value of the difference between the thickness of the negative tab at different positions and the initial average thickness of the nickel phosphide layer.

[0103]

[0104]

[0105] Conclusion: As can be seen from the comparison of Example 1-Example 3 and Comparative Example 1, the thickness fluctuation of the nickel phosphide layer formed by the application by using the pulse alternating current power supply for electroplating is less than or equal to 0.3 μm, which shows that the application can reduce the thickness fluctuation of the nickel phosphide layer while reducing the cost of forming the nickel phosphide layer. In addition, the nickel phosphide layer formed by using the pulse alternating current power supply has better electrolyte resistance.

[0106] As can be seen from the comparison of Example 1-Example 3 and Comparative Example 2, the application can reduce the thickness fluctuation of the nickel phosphide layer by using the pulse alternating current power supply instead of the direct current power supply for electroplating, thereby improving the uniformity of the thickness distribution of the corrosion-resistant layer on the surface of the substrate and improving the electrolyte resistance of the negative tab.

[0107] Although the embodiments of the application have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments within the scope of the application.

Claims

1. A method of preparing a negative electrode tab, characterized by, Comprising: placing a metal nickel and copper strip in an electroplating solution comprising a nickel salt and a phosphorus salt, and forming a corrosion-resistant layer on at least one side of the substrate under the action of an alternating current power supply; wherein the positive voltage of the alternating current power supply lasts for a time t1, and the reverse voltage lasts for a time t2, and t1:t2=(2-10):1 is satisfied; the material forming the corrosion-resistant layer comprises nickel phosphide, and the thickness fluctuation of the corrosion-resistant layer is less than or equal to 0.3 μm.

2. The method of claim 1, wherein, The current density of the alternating current power source is 2 A / dm 2 -5 A / dm 2 .

3. The method of claim 1, wherein, At least one of the following conditions is satisfied: the mass concentration of the nickel salt in the electroplating solution is 60 g / L-150 g / L; the mass concentration of the phosphorus salt in the electroplating solution is 10 g / L-30 g / L; the pH of the electroplating solution is 2-5; the temperature of the electroplating solution is 40°C-70°C.

4. The method of claim 1, wherein, The alternating current power supply is a pulse alternating current power supply.

5. The method of claim 1, wherein, Further comprising: a process of soaking the substrate on which the corrosion-resistant layer is formed in a passivation solution.

6. A negative tab, characterized by, The negative electrode tab is prepared by the method of any one of claims 1-5.

7. The negative tab of claim 6, wherein, The thickness of the corrosion-resistant layer is 0.6 μm-2.4 μm.

8. The negative tab according to claim 6 or 7, characterized in that, The corrosion-resistant layer is arranged on at least one side in the thickness direction of the substrate.

9. The negative tab according to claim 6 or 7, characterized in that, The material forming the substrate comprises copper.

10. A negative electrode sheet characterized by comprising: The negative electrode tab comprises the negative electrode tab of any one of claims 6-9 or the negative electrode tab prepared by the method of any one of claims 1-5.

11. A pouch battery, characterized by, The negative electrode tab piece comprises the negative electrode tab piece of claim 10.

12. A vehicle characterized by comprising: The soft package battery comprises the soft package battery of claim 11.

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