CN110729445A - Coated tab and method of making the same, cell, battery and power tool - Google Patents

Abstract

The invention discloses a pole ear with a coating and a preparation method thereof, a battery core, a battery and an electric tool, and relates to the technical field of battery pole ears. The coated tab includes a tab base, and a copper layer and a transition metal boride/nickel composite coating sequentially disposed on the surface of the tab base. The preparation method includes the following steps: preparing a copper layer and a transition metal boride/nickel composite coating on the electrode tab substrate in turn by means of physical vapor deposition to obtain a electrode tab with a coating. In the invention, a copper layer is deposited on the surface of the tab base to improve the electrical conductivity of the tab, and then a transition metal boride/nickel composite coating is deposited on the copper layer to improve the surface corrosion resistance of the tab, thereby improving the work of the tab. performance and battery life.

Description

Coated tab and method of making the same, cell, battery and power tool

technical field

The present invention relates to the technical field of battery tabs, in particular, to a tab with a coating and a preparation method thereof, a battery cell, a battery and an electric tool.

Background technique

The tab is a device in the battery that connects the positive and negative electrodes. The battery is divided into positive and negative poles, and the pole ear is the metal conductor that leads the positive and negative poles from the battery core. In layman's terms, the ears of the positive and negative poles of the battery are the contact points during charging and discharging. Generally, an aluminum (Al) material is used for the positive electrode of a battery, and a nickel (Ni) material is used for the negative electrode. Due to the large resistance of nickel, when the battery is discharged at a high rate, due to the low conductivity of the negative electrode, the surface temperature of the battery is too high, which affects the high-rate discharge performance of the battery, and affects the capacity and cycle life of the battery. In addition, nickel has poor corrosion resistance and will be corroded in the electrolyte, which will also affect the performance and service life of the battery.

At present, there are not many studies on improving the performance of the tab by preparing a coating on the tab. Patent CN105063699A proposes a nickel-plated copper material as the negative tab, which solves the problem of poor conductivity of the nickel tab, but the outermost layer is still Because of the nickel layer, the corrosion resistance of the tabs cannot be solved.

In view of this, the present invention is proposed.

SUMMARY OF THE INVENTION

One of the objectives of the present invention is to provide a pole ear with a coating, which improves the electrical conductivity and surface corrosion resistance of the pole ear, and prolongs the service life of the battery.

The second purpose of the present invention is to provide a preparation method of a pole ear with a coating, which adopts physical vapor deposition to deposit a copper layer and a transition metal boride/nickel composite coating on the pole ear substrate in turn, which has strong operability, Good controllability, easy to implement, and convenient for large-scale continuous industrial production.

The third object of the present invention is to provide a battery core, which is a tab obtained by welding the above-mentioned coated tab or the above-mentioned preparation method of the coated tab after assembling the negative pole piece, the separator and the positive pole piece. owned.

The fourth object of the present invention is to provide a battery, including the above-mentioned tab with a coating, or a tab prepared by the above-mentioned method for preparing a tab with a coating, or the above-mentioned battery core.

The fifth object of the present invention is to provide a power tool including the above-mentioned battery.

In order to realize the above-mentioned purpose of the present invention, the following technical solutions are specially adopted:

In a first aspect, a coated tab is provided, comprising a tab base, and a copper layer and a transition metal boride/nickel composite coating sequentially disposed on the surface of the tab base.

Preferably, the tabs are negative nickel tabs.

Preferably, based on the technical solutions of the present invention, the thickness of the copper layer is 0.6-1.4 μm, preferably 0.8-1.4 μm, and more preferably 0.8-1.2 μm.

Preferably, based on the technical solution of the present invention, the transition metal boride is ReB ₂ , IrB _1.1 , WB, WB ₄ , TiB ₂ or CrB ₂ , preferably TiB ₂ or CrB ₂ , more preferably TiB ₂ .

Preferably, based on the technical solution of the present invention, the thickness of the transition metal boride/nickel composite coating is 1-2 μm, preferably 1.2-1.8 μm, and more preferably 1.2-1.5 μm.

In a second aspect, a preparation method of the above-mentioned electrode lug with coating is provided, comprising the following steps:

A copper layer and a transition metal boride/nickel composite coating are sequentially prepared on the tab substrate by means of physical vapor deposition to obtain a tab with a coating.

Preferably, on the basis of the technical solution of the present invention, the deposition conditions for preparing the copper layer by physical vapor deposition include: using copper as the target material, the copper target power is 1.8-3.0kW, the deposition pressure is 0.2-1.3Pa, the substrate is The bias voltage is -50～-300V, and the deposition time is 10～15min.

Preferably, on the basis of the technical solution of the present invention, the deposition conditions for preparing the transition metal boride/nickel composite coating by means of physical vapor deposition include: using transition metal boride and nickel as targets, transition metal boride target power It is 1.5-2.5kW, the nickel target power is 1.0-2.0kW, the deposition pressure is 0.2-1.3Pa, the substrate bias is -50--200V, and the deposition time is 10-20min.

Preferably, on the basis of the technical solution of the present invention, the method further includes pre-processing, glow cleaning and ion etching cleaning on the tab substrate first, and then preparing sequentially on the tab substrate by means of physical vapor deposition the step of copper layer and transition metal boride/nickel composite coating;

Preferably, the pretreatment includes the steps of cleaning the tab base and preheating the tab base;

Preferably, the cleaning of the tab base includes the following steps: ultrasonic cleaning with water, ketones and alcohols for 5-20 minutes in sequence, and drying;

Preferably, preheating the tab substrate includes the following steps: fixing the cleaned tab substrate on the turret of the coating equipment; closing the door of the vacuum chamber, vacuuming to below 5.0×10 ^-3 Pa, and then heating and baking the vacuum chamber. The temperature is 100～500℃, when the vacuum degree reaches 3.0×10 ^-3 Pa, the glow cleaning is performed;

Preferably, the glow cleaning comprises the following steps:

Pour argon gas into the vacuum chamber, the flow rate of argon gas is 300～500sccm, the working pressure is 1.0～1.7Pa, the bias voltage of the substrate is -500～-800V, and the surface of the base body of the electrode ear is cleaned by glow, and the cleaning time is 10～30min;

Preferably, the ion etching cleaning includes the following steps:

Turn on the ion source to clean the tab substrate by ion bombardment. The ion source voltage is 50-90V, the argon flow rate is 200-500sccm, the working pressure is 0.5-1.7Pa, the substrate bias is -100--500V, and the cleaning time is 10-30min.

In a third aspect, a battery cell is provided, which is obtained by assembling the negative pole piece, the separator and the positive pole piece and then welding the above-mentioned coated tab or the above-mentioned coated tab prepared by the method for preparing the tab. .

In a fourth aspect, a battery is provided, including the above-mentioned tab with a coating, or a tab prepared by the above-mentioned method for preparing a tab with a coating, or the above-mentioned battery core.

In a fifth aspect, an electric power tool is provided, including the above-mentioned battery.

Compared with the prior art, the present invention has the following beneficial effects:

(1) In the present invention, a copper layer is arranged on the surface of the tab base to improve the electrical conductivity of the tab, and then a transition metal boride/nickel composite coating is deposited on the copper layer, and the transition metal boride/nickel composite coating can not only improve the polar The corrosion resistance of the ear surface can further improve the electrical conductivity of the tab. The tab with the coating has high electrical conductivity and corrosion resistance, and can improve the working performance of the tab and the service life of the battery. The lithium ion battery made by using the tab of the invention has good cycle performance and high capacity retention rate after 400 times.

(2) The copper layer and the transition metal boride/nickel composite coating are prepared by the physical vapor deposition method. The process is simple, and the PVD equipment can be used to realize automatic production. It has strong operability, good controllability, easy implementation, and is convenient for large-scale continuous chemical industry production.

Description of drawings

FIG. 1 is a schematic structural diagram of a tab with a coating according to an embodiment of the present invention.

Reference numerals: 10 - tab substrate; 20 - copper layer; 30 - transition metal boride/nickel composite coating.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

According to a first aspect of the present invention, a coated tab is provided. As shown in FIG. 1 , the coated tab includes a tab base 10 and a copper layer sequentially disposed on the surface of the tab base 10 20 and transition metal boride/nickel composite coating 30.

The tabs include positive tabs and negative tabs. The positive tabs are usually made of aluminum, and the negative tabs are usually made of nickel. Since nickel has poor electrical conductivity and corrosion resistance, the tabs of the present invention preferably refer to negative nickel tabs or negative electrodes. Nickel alloy tabs.

The copper layer refers to a coating made of metallic copper nano-powder or a thin film with a dense structure. Copper has good electrical conductivity, and the electrical conductivity of the tab can be significantly improved by arranging the copper layer on the tab base.

The thickness of the copper layer is not limited, but is preferably 0.6 to 1.4 μm, more preferably 0.8 to 1.4 μm, and still more preferably 0.8 to 1.2 μm. A suitable thickness of the copper layer can better improve the electrical conductivity of the tab, and will not cause the influence of electron transport and the weakening of the bonding strength between the transition metal boride/nickel composite coating and the substrate due to the excessive thickness of the intermediate layer.

"/" in "transition metal boride/nickel composite coating" means "and", which refers to the composite coating of transition metal boride and nickel. The ratio of transition metal boride to nickel in the composite coating of transition metal boride and nickel is not limited, and can be any ratio. Preferably, in the composite coating of transition metal boride and nickel, nickel accounts for the mass percentage of the entire coating. 30-70%.

Transition metal borides mainly refer to 5d transition metal borides, typically ReB ₂ , IrB _1.1 , WB, WB ₄ , TiB ₂ or CrB ₂ , etc. Transition metal borides have high hardness, high melting point, chemical inertness, high temperature oxidation resistance, and good thermal and electrical conductivity.

Preferably, the transition metal boride is TiB ₂ or CrB ₂ , more preferably TiB ₂ . That is, the transition metal boride/nickel composite coating is preferably a TiB ₂ /nickel composite coating.

The transition metal boride/nickel composite coating can further improve the electrical conductivity and surface corrosion resistance of the tab, and the use of transition metal boride and nickel composite can improve the welding performance.

The thickness of the transition metal boride/nickel composite coating is not limited, but is preferably 1 to 2 μm, more preferably 1.2 to 1.8 μm, and still more preferably 1.2 to 1.5 μm. A suitable thickness of transition metal boride/nickel composite coating can make the tab obtain perfect electrical conductivity and surface corrosion resistance, and will not cause the bonding strength between the entire coating and the substrate to be weakened due to the excessive thickness of the outer layer.

In the present invention, a copper layer is arranged on the surface of the tab base to improve the electrical conductivity of the tab, and then a transition metal boride/nickel composite coating is deposited on the copper layer. The transition metal boride/nickel composite coating can not only improve the surface of the tab It has high corrosion resistance and can further improve the electrical conductivity of the tab. The tab with the coating has high electrical conductivity and corrosion resistance, and can improve the working performance of the tab and the service life of the battery.

The copper layer and transition metal boride/nickel composite coating can be prepared by methods known in the art, such as chemical vapor deposition (CVD), physical vapor deposition (PVD), sol coating, Pulse electrode deposition (PES), laser surface modification, electrochemical method, thermal spraying method, self-propagating high temperature synthesis technology, etc., preferably physical vapor deposition method.

According to a second aspect of the present invention, there is provided a method for preparing the above-mentioned electrode lug with coating, comprising the following steps: preparing a copper layer and transition metal boride/nickel on the electrode lug substrate in turn by means of physical vapor deposition The composite coating results in a coated tab.

A typical but non-limiting physical vapor deposition method is magnetron sputtering, which has the advantages of simple equipment, easy control, large coating area and strong adhesion.

The copper layer and the transition metal boride/nickel composite coating are prepared by the physical vapor deposition method. The process is simple, the operability is strong, the controllability is good, and the implementation is easy. The PVD equipment used can realize automatic production, and does not need to be used in the preparation process. It has the advantages of efficient, fast, safe and automatic production, which is convenient for large-scale continuous industrial production.

In an optional embodiment, the deposition conditions for preparing the copper layer include: using copper as the target material, the copper target power is 1.8-3.0kW, the deposition pressure is 0.2-1.3Pa, the substrate bias is -50--300V, and the deposition time is 10 to 15 minutes.

Specifically, it includes: feeding argon with a flow rate of 100-400sccm, such as 100sccm, 200sccm, 300sccm or 400sccm, and adjusting the vacuum chamber pressure to 0.2-1.3Pa, such as 0.2Pa, 0.4Pa, 0.5Pa, 1Pa or 1.3Pa ; Turn on the copper target, the target power is 1.8~3.0kW, such as 1.8kW, 2kW, 2.5kW or 3.0kW, and the substrate bias is -50~-300V, such as -50V, -100V, -150V, -200V, - 250V or -300V, the deposition of metallic copper is carried out, and the deposition time is 10-15 minutes, for example, 10 minutes, 12 minutes or 15 minutes.

By controlling the deposition conditions and process parameters, a metal copper coating with a thickness of 0.6-1.4 μm and a dense structure can be obtained.

In an optional embodiment, the deposition conditions for preparing the transition metal boride/nickel composite coating include: using transition metal boride and nickel as targets, the transition metal boride target power is 1.5-2.5kW, and the nickel target power is 1.0- 2.0kW, the deposition pressure is 0.2-1.3Pa, the substrate bias is -50--200V, and the deposition time is 10-20min.

Specifically, it includes: after the metal copper deposition is completed, keep the pressure in the vacuum chamber, turn on the transition metal boride target and the nickel target, the power of the transition metal boride target is 1.5-2.5kW, such as 1.5kW, 2kW or 2.5kW, and the power of the nickel target is 1.5-2.5kW. 1.0~2.0kW, such as 1kW, 1.5kW or 2kW, the substrate bias voltage is -50~-200V, such as -50V, -100V, -150V or -200V, and the deposition of transition metal boride and nickel is carried out, and the deposition time is 10 to 25 minutes, for example, 10 minutes, 12 minutes, 15 minutes or 20 minutes.

By controlling the deposition conditions and process parameters, a transition metal boride/nickel composite coating with a thickness of 1-2 μm and a dense structure can be obtained. By controlling the power of the transition metal boride target and the nickel target, the transition metal boron in the composite coating can be adjusted. proportions of compounds and nickel.

In a preferred embodiment, the preparation method of the electrode tab with coating further comprises pre-processing, glow cleaning and ion etching cleaning on the tab substrate first, and then sequentially depositing the tab substrate on the tab substrate by means of physical vapor deposition. Steps for preparing copper layers and transition metal boride/nickel composite coatings.

Preferably, the pretreatment includes the steps of cleaning the tab base and preheating the tab base;

Preferably, cleaning the tab substrate includes the following steps: ultrasonic cleaning with water, ketones and alcohols in sequence for 5-20 min, and drying; preferably the ketones are acetone, and the alcohols are preferably ethanol, and the preferred drying method is to dry the surface of the tabs with nitrogen, Then put it in a drying oven to dry at 80-150 °C;

Preferably, preheating the tab substrate includes the following steps: fixing the cleaned tab substrate on the turret of the coating equipment; closing the door of the vacuum chamber, vacuuming to below 5.0×10 ^-3 Pa, and then heating and baking the vacuum chamber. The temperature is 100-500°C, and when the vacuum degree reaches 3.0×10 ^-3 Pa, glow cleaning is performed.

Preferably, the glow cleaning comprises the following steps:

Pour argon gas into the vacuum chamber, the flow rate of argon gas is 300～500sccm, the working pressure is 1.0～1.7Pa, the substrate bias is -500～-800V, and the surface of the tab substrate is glow cleaned, and the cleaning time is 10～30min.

Preferably, the ion etching cleaning includes the following steps:

Turn on the ion source to clean the tab substrate by ion bombardment. The ion source voltage is 50-90V, the argon flow rate is 200-500sccm, the working pressure is 0.5-1.7Pa, the substrate bias is -100--500V, and the cleaning time is 10-30min.

Preferably, a typical preparation method of a pole ear with a coating comprises the following steps:

(a) Pretreatment: first put the electrode base in water for ultrasonic cleaning for 5-20 minutes, then put it in acetone for ultrasonic cleaning for 10-20 minutes, and then put it in ethanol for ultrasonic cleaning for 10-20 minutes, and then use dry nitrogen to clean the electrodes. Dry the surface, and finally put the base of the tabs in a blast drying oven at 80-150°C for drying; fix the dried tabs on the turntable in the coating equipment; close the door of the vacuum chamber and evacuate ; When the vacuum chamber pressure is pumped to 5.0×10 ^-3 Pa, turn on the heating power supply to heat and bake the vacuum chamber, the heating temperature is 100～500℃, when the vacuum degree reaches 3.0×10 ^-3 Pa, the glow starts cleaning;

(b) Glow cleaning: Open the main valve, pressure reducing valve, ion source valve, arc valve, target valve and mass flow meter of the argon cylinder and introduce argon into the vacuum chamber. The argon flow rate is 300-500sccm, and the working pressure is 1.0 ～1.7Pa, substrate bias voltage -500～-800V, glow cleaning for tab substrate, cleaning time 10～30min;

(c) Ion etching cleaning: After the glow cleaning, turn on the ion source to clean the sample by ion bombardment. The ion source voltage is 50-90V, the argon gas flow is 200-500sccm, the working pressure is 0.5-1.7Pa, and the substrate bias is -100～-500V, cleaning time 10～30min;

(d) Deposition of metallic copper: after the ion etching and cleaning, pass argon gas, the flow rate is 100-400sccm, adjust the vacuum chamber pressure to 0.2-1.3Pa, turn on the copper target, the target power is 1.8-3.0kW, the substrate is biased Press -50～-300V to deposit copper metal, and the deposition time is 10～15min to obtain a copper layer;

(e) Deposition of transition metal boride and nickel: After the deposition of metal copper, the transition metal boride target and the nickel target are turned on. The power of the transition metal boride target is 1.5-2.5kW, and the power of the nickel target is 1.0-2.0kW , the substrate bias voltage is -50~-200V, and the deposition time is 10-20min to obtain the transition metal boride/nickel composite coating;

(f) After the coating deposition is completed, turn off the ion source power supply, bias power supply, gas mass flow meter, gas cylinder main valve and pressure reducing valve; when the temperature drops below 100 °C, close the high valve and open the gas release valve, When the pressure in the vacuum chamber is consistent with the outside air pressure, the door of the vacuum chamber is opened, and the coated tab is taken out.

According to a third aspect of the present invention, a battery cell is provided, which is obtained by assembling the negative electrode piece, the separator and the positive electrode piece and then welding the above-mentioned coated tab or the above-mentioned preparation method of the coated tab. obtained from the polar ear.

By using the electrode lugs with the coating of the invention, the electric conductivity and corrosion resistance of the electric core can be improved, and the service life of the electric core can be prolonged.

According to a fourth aspect of the present invention, a battery is provided, comprising the above-mentioned tab with a coating, or a tab prepared by the above-mentioned method for preparing a tab with a coating, or the above-mentioned battery core.

The battery has the same advantages as the coated tab or battery core of the present invention, and the battery has good working performance and service life.

According to a fifth aspect of the present invention, there is provided an electric power tool, comprising the above-mentioned battery.

A power tool is a power tool that uses a battery as a driving power source to move a moving part (eg, a drill).

The same effect can also be obtained in a power tool using the battery of the embodiment of the present invention.

The present invention is further described below through specific examples and comparative examples, however, it should be understood that these examples are only used for more detailed description, and should not be construed to limit the present invention in any form. Each raw material involved in the present invention can be obtained commercially.

Transition metal borides are exemplified by TiB ₂ .

The present embodiment and comparative example use the negative electrode nickel tabs sold in the domestic market as the base.

Example 1

A pole ear with coating comprises a pole ear base body, a copper layer and a titanium diboride/nickel composite coating which are sequentially arranged on the surface of the pole ear base body.

The preparation method of the pole ear with coating comprises the following steps:

(1) Pretreatment: first put the tab substrate into water for ultrasonic cleaning for 20 minutes, then put it in acetone for ultrasonic cleaning for 10 minutes, then put it in ethanol for ultrasonic cleaning for 10 minutes, then dry the surface of the tab with dry nitrogen, and finally Put the polar ear base into a blast drying oven at 80°C for drying;

Fix the dried tabs on the turret in the cavity of the ion source/arc ion plating composite coating equipment; close the vacuum chamber door, and open the water cooler to remove the ion source, multi-arc target, molecular pump, and vacuum chamber. Turn on the water circuit, turn on the main power of the air compressor and the composite coating machine, then turn on the mechanical pump, the bypass valve and the molecular pump, so that the molecular pump enters the climbing state; when the molecular pump reaches full speed, close the bypass valve and open the rough pumping. When the pressure in the vacuum chamber reaches below 10Pa, open the side pumping valve again; when the pressure in the vacuum chamber reaches below 3Pa, close the roughing valve and open the high valve to pump high vacuum into the vacuum chamber; After the chamber pressure was pumped to 5.0×10 ^-3 Pa, the heating power was turned on to heat and bake the vacuum chamber, and the heating temperature was 100°C. When the vacuum degree reached 3.0×10 ^-3 Pa, the glow cleaning was started;

(2) Glow cleaning: Open the main valve, pressure reducing valve, ion source valve, arc valve, target valve and mass flow meter of the argon cylinder and introduce argon into the vacuum chamber. The argon flow rate is 300sccm, and the working pressure is 1.0Pa. The substrate bias voltage is -500V, and the tab substrate is glow cleaned, and the cleaning time is 30min;

(3) Ion etching cleaning: After glow cleaning, turn on the ion source to clean the sample by ion bombardment. The ion source voltage is 50V, the argon flow rate is 200sccm, the working pressure is 0.5Pa, the substrate bias is -100V, and the cleaning time is 30min. ;

(4) Deposition of metallic copper: after the ion etching and cleaning is completed, argon gas is introduced, the flow rate is 300sccm, the pressure of the vacuum chamber is adjusted to 0.8Pa, the copper target is turned on, the target power is 2.0kW, and the substrate bias voltage is -200V to carry out metallic copper. , the deposition time is 10min, and the copper layer with a thickness of 0.6μm is obtained;

(5) Deposition of titanium diboride and nickel: After the deposition of metal copper, the titanium diboride target and the nickel target are turned on. The power of the titanium diboride target is 2kW, the power of the nickel target is 1.5kW, and the substrate bias is -150V, deposition time is 20min, a titanium diboride/nickel composite coating with a thickness of 1.5μm is obtained;

(6) After the coating deposition is completed, turn off the ion source power supply, bias power supply, mass flow meter, gas cylinder main valve and pressure reducing valve; when the temperature drops below 100 °C, close the high valve, open the vent valve, and wait until the temperature drops below 100°C. When the pressure in the vacuum chamber is consistent with the outside air pressure, the door of the vacuum chamber is opened, and the coated tab is taken out.

Example 2

A pole ear with coating comprises a pole ear base body, a copper layer and a titanium diboride/nickel composite coating which are sequentially arranged on the surface of the pole ear base body.

The preparation method of the pole ear with coating comprises the following steps:

(1) Pretreatment: first put the tab substrate into water for ultrasonic cleaning for 5 minutes, then put it in acetone for ultrasonic cleaning for 20 minutes, then put it in ethanol for ultrasonic cleaning for 20 minutes, then dry the surface of the tab with dry nitrogen, and finally Put the base of the tabs into a blast drying oven and dry at 150°C;

Fix the dried tabs on the turret in the cavity of the ion source/arc ion plating composite coating equipment; close the vacuum chamber door, and open the water cooler to remove the ion source, multi-arc target, molecular pump, and vacuum chamber. Turn on the water circuit, turn on the main power of the air compressor and the composite coating machine, then turn on the mechanical pump, the bypass valve and the molecular pump, so that the molecular pump enters the climbing state; when the molecular pump reaches full speed, close the bypass valve and open the rough pumping. When the pressure in the vacuum chamber reaches below 10Pa, open the side pumping valve again; when the pressure in the vacuum chamber reaches below 3Pa, close the roughing valve and open the high valve to pump high vacuum into the vacuum chamber; After the chamber pressure was pumped to 5.0×10 ^-3 Pa, the heating power was turned on to heat and bake the vacuum chamber, and the heating temperature was 500°C. When the vacuum degree reached 3.0×10 ^-3 Pa, the glow cleaning was started;

(2) Glow cleaning: Open the main valve, pressure reducing valve, ion source valve, arc valve, target valve and mass flow meter of the argon cylinder and introduce argon into the vacuum chamber. The argon flow rate is 500sccm, and the working pressure is 1.7Pa. The substrate bias voltage is -800V, and the tab substrate is glow cleaned, and the cleaning time is 10min;

(3) Ion etching cleaning: After the glow cleaning, turn on the ion source to clean the sample by ion bombardment. The ion source voltage is 90V, the argon flow rate is 500sccm, the working pressure is 1.7Pa, the substrate bias is -500V, and the cleaning time is 10min. ;

(4) Deposition of metallic copper: after the ion etching and cleaning is completed, argon gas is introduced, the flow rate is 100sccm, the vacuum chamber pressure is adjusted to 0.2Pa, the copper target is turned on, the target power is 1.8kW, and the substrate bias is -50V to carry out metallic copper. , the deposition time was 12 min, and the copper layer with a thickness of 0.8 μm was obtained;

(5) Deposition of titanium diboride and nickel: After the deposition of metallic copper, the titanium diboride target and the nickel target are turned on. The power of the titanium diboride target is 1.5kW, the power of the nickel target is 1.0kW, and the substrate bias is is -50V, the deposition time is 10min, and the titanium diboride/nickel composite coating with a thickness of 1μm is obtained;

(6) After the coating deposition is completed, turn off the ion source power supply, bias power supply, mass flow meter, gas cylinder main valve and pressure reducing valve; when the temperature drops below 100 °C, close the high valve, open the vent valve, and wait until the temperature drops below 100°C. When the pressure in the vacuum chamber is consistent with the outside air pressure, the door of the vacuum chamber is opened, and the coated tab is taken out.

Example 3

A pole ear with coating comprises a pole ear base body, a copper layer and a titanium diboride/nickel composite coating which are sequentially arranged on the surface of the pole ear base body.

The preparation method of the pole ear with coating comprises the following steps:

(1) Pretreatment: first put the tab substrate into water for ultrasonic cleaning for 10 minutes, then put it in acetone for ultrasonic cleaning for 15 minutes, then put it in ethanol for ultrasonic cleaning for 15 minutes, then dry the surface of the tab with dry nitrogen, and finally Put the base of the tabs into a blast drying oven and dry at 120°C;

Fix the dried tabs on the turret in the cavity of the ion source/arc ion plating composite coating equipment; close the vacuum chamber door, and open the water cooler to remove the ion source, multi-arc target, molecular pump, and vacuum chamber. Turn on the water circuit, turn on the main power of the air compressor and the composite coating machine, then turn on the mechanical pump, the bypass valve and the molecular pump, so that the molecular pump enters the climbing state; when the molecular pump reaches full speed, close the bypass valve and open the rough pumping. When the pressure in the vacuum chamber reaches below 10Pa, open the side pumping valve again; when the pressure in the vacuum chamber reaches below 3Pa, close the roughing valve and open the high valve to pump high vacuum into the vacuum chamber; After the chamber pressure is pumped to 5.0×10 ^-3 Pa, the heating power is turned on to heat and bake the vacuum chamber, and the heating temperature is 300°C. When the vacuum degree reaches 3.0×10 ^-3 Pa, the glow cleaning starts;

(2) Glow cleaning: Open the main valve, pressure reducing valve, ion source valve, arc valve, target valve and mass flow meter of the argon cylinder and introduce argon into the vacuum chamber. The argon flow rate is 400sccm, and the working pressure is 1.3Pa. The substrate bias voltage is -600V, and the tab substrate is glow cleaned, and the cleaning time is 20min;

(3) Ion etching cleaning: After glow cleaning, turn on the ion source to clean the sample by ion bombardment. The ion source voltage is 60V, the argon flow rate is 300sccm, the working pressure is 1.2Pa, the substrate bias is -400V, and the cleaning time is 20min. ;

(4) Deposition of metal copper: after the ion etching and cleaning, pass argon gas, the flow rate is 400sccm, adjust the vacuum chamber pressure to 1.3Pa, turn on the copper target, the target power is 3.0KW, the substrate bias is -300V to carry out metal copper , the deposition time is 12min, and a copper layer with a thickness of 1μm is obtained;

(5) Deposition of titanium diboride and nickel: After the metal copper deposition is completed, the titanium diboride target and the nickel target are turned on. The power of the titanium diboride target is 2.5kW, the power of the nickel target is 2.0kW, and the substrate bias is is -200V, the deposition time is 15min, and a titanium diboride/nickel composite coating with a thickness of 1.2 μm is obtained;

(6) After the coating deposition is completed, turn off the ion source power supply, bias power supply, mass flow meter, gas cylinder main valve and pressure reducing valve; when the temperature drops below 100 °C, close the high valve, open the vent valve, and wait until the temperature drops below 100°C. When the pressure in the vacuum chamber is consistent with the outside air pressure, the door of the vacuum chamber is opened, and the coated tab is taken out.

Example 4

The difference between Example 4 and Example 1 is that in step (4), the target power is 1.5kW, and the substrate bias voltage is -400V to deposit metal copper, and the deposition time is 20min to obtain a copper layer with a thickness of 1.6 μm.

Example 5

The difference between Example 5 and Example 1 is that in step (5), the power of the titanium diboride target is 0.5 kW, and the power of the nickel target is 2.5 kW, to obtain a titanium diboride/nickel composite coating with a thickness of 1.5 μm .

Comparative Example 1

Commercially available negative nickel tabs, Dongguan Huachuang Power Supply Co., Ltd.

Comparative Example 2

A pole ear with coating comprises a pole ear base body and a titanium diboride/nickel composite coating arranged on the surface of the pole ear base body.

Comparative Example 3

A pole ear with coating comprises a pole ear base body and a copper layer arranged on the surface of the pole ear base body.

Comparative Example 4

The difference between Comparative Example 4 and Example 1 is that copper is replaced with aluminum.

Comparative Example 5

A pole ear with coating comprises a pole ear base body and a carbon layer arranged on the surface of the pole ear base body.

The preparation method of the pole ear with coating comprises the following steps:

First, clean the surface of the nickel strip in distilled water at 100 °C to clean the surface oil and other impurities, then take it out and cool it, then clean it with absolute ethanol, and dry it under vacuum at 70 °C; use the magnetron sputtering method to sputter carbon powder to the cleaning The process parameters of the surface of the nickel strip are as follows: using carbon powder as the sputtering target, nickel strip as the sputtering substrate, pre-evacuating the cavity to 4 × 10 ^-3 Pa, and then pouring argon into the cavity to control The pressure in the chamber is 3mTorr and the substrate nickel strip is heated to 200°C, the acceleration voltage: 400V, the magnetic field is about 150G, the current density: 20mA/cm, the power density: 10W/cm, and the nickel strip after magnetron sputtering is placed. In a hydrogen heat treatment furnace, the heat treatment temperature was 350° C. and the holding time was 5 hours. The thickness of the carbon layer was 3 μm.

Comparative Example 6

A pole ear with a graphene film, comprising a pole ear base and a graphene layer arranged on the surface of the pole ear base, wherein the thickness of the graphene layer is 1 μm, and the preparation method is to coat the graphene slurry on the surface of the pole ear base and dry obtained after.

Performance tests are carried out to the tabs obtained in the examples and comparative examples, and the following test methods are specifically used to evaluate:

(1) Corrosion resistance test: soak the coated tab with 1% HF, and test the peeling area of the coating after 12 hours;

(2) The above-mentioned tabs were made into lithium ion batteries according to the conventional production method, the cycle performance of the lithium ion battery 20C was tested, and the capacity retention rate after 400 cycles was recorded.

The test results are shown in Table 1.

Table 1

It can be seen from Table 1 that the tabs of the present invention are corrosion-resistant and have good electrical conductivity, and the lithium ion batteries made by using the tabs of the present invention have good cycle performance and high capacity retention rate after 400 cycles.

The electrical conductivity of Comparative Example 2 is not as good as that of Example 1, and the electrical conductivity and corrosion resistance of Comparative Example 3 are not as good as that of Example 1. In Comparative Example 4, copper was replaced by aluminum, and the conductivity was not as good as that of copper, because copper resistivity (ρ/nΩ·m) was 16.78, and the conductivity was excellent. The present invention is comparable to the tabs of Comparative Example 5 with a carbon layer and Comparative Example 6 with a graphene layer, and the coating of the present invention significantly improves the corrosion resistance of the tabs.

Compared with Example 5, the titanium diboride/nickel composite coating in Example 1 has higher titanium diboride content, higher titanium diboride content, and better tab corrosion resistance.

While specific embodiments of the present invention have been illustrated and described, it should be understood that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that all such changes and modifications as fall within the scope of this invention be included in the appended claims.

Claims (10)

1. The utility model provides a utmost point ear with coating which characterized in that, includes utmost point ear base member, and set gradually in copper layer and transition metal boride/nickel composite coating on utmost point ear base member surface.

2. The coated tab of claim 1 wherein the tab is a negative nickel tab.

3. The coated tab as claimed in claim 1, wherein the copper layer has a thickness of 0.6 to 1.4 μm, preferably 0.8 to 1.4 μm, and more preferably 0.8 to 1.2 μm.

4. A coated tab as claimed in any one of claims 1 to 3, wherein the transition metal boride is ReB₂、IrB_1.1、WB、WB₄、TiB₂Or CrB₂Preferably TiB₂Or CrB₂More preferably TiB₂；

Preferably, the thickness of the transition metal boride/nickel composite coating is 1-2 μm, preferably 1.2-1.8 μm, and more preferably 1.2-1.5 μm.

5. The preparation method of the electrode tab with the coating layer as set forth in any one of claims 1 to 4, which is characterized by comprising the following steps:

and sequentially preparing a copper layer and a transition metal boride/nickel composite coating on the tab substrate by adopting a physical vapor deposition mode to obtain the tab with the coating.

6. The method for preparing a coated tab as claimed in claim 5, wherein the deposition conditions for preparing the copper layer by physical vapor deposition include: copper is used as a target material, the power of the copper target is 1.8-3.0kW, the deposition air pressure is 0.2-1.3 Pa, the bias voltage of a matrix is-50-300V, and the deposition time is 10-15 min;

preferably, the deposition conditions for preparing the transition metal boride/nickel composite coating by physical vapor deposition comprise: transition metal boride and nickel are used as target materials, the power of the transition metal boride target is 1.5-2.5kW, the power of the nickel target is 1.0-2.0kW, the deposition air pressure is 0.2-1.3 Pa, the bias voltage of a matrix is-50-200V, and the deposition time is 10-20 min.

7. The method for preparing the tab with the coating according to claim 5 or 6, further comprising the steps of pretreating, glow cleaning and ion etching cleaning the tab substrate, and then sequentially preparing a copper layer and a transition metal boride/nickel composite coating on the tab substrate in a physical vapor deposition manner;

preferably, the pretreatment comprises the steps of cleaning the tab matrix and preheating the tab matrix;

preferably, the step of cleaning the tab matrix comprises the following steps: ultrasonic cleaning with water, ketones and alcohols for 5-20 min in sequence, and drying;

preferably, the preheating of the tab substrate comprises the following steps: fixing the cleaned tab substrate on a rotary frame of coating equipment; closing the vacuum chamber door, and vacuumizing to 5.0 × 10^-3Heating and baking the vacuum chamber after the pressure is less than Pa, wherein the heating temperature is 100-500 ℃, and when the vacuum degree reaches 3.0 multiplied by 10^-3When Pa, glow cleaning is carried out;

preferably, the glow cleaning comprises the steps of:

introducing argon into the vacuum chamber, wherein the flow of the argon is 300-500 sccm, the working pressure is 1.0-1.7 Pa, the bias voltage of the substrate is-500 to-800V, and the surface of the auricle substrate is subjected to glow cleaning for 10-30 min;

preferably, the ion etching cleaning comprises the following steps:

and opening an ion source to perform ion bombardment cleaning on the lug substrate, wherein the voltage of the ion source is 50-90V, the argon flow is 200-500 sccm, the working pressure is 0.5-1.7 Pa, the bias voltage of the substrate is-100-500V, and the cleaning time is 10-30 min.

8. An electric core, characterized in that the electric core is obtained by welding the tab with the coating according to any one of claims 1 to 4 or the tab prepared by the preparation method of the tab with the coating according to any one of claims 5 to 7 after assembling a negative pole piece, a diaphragm and a positive pole piece.

9. A battery comprising the coated tab of any one of claims 1-4, or the tab prepared by the method of any one of claims 5-7, or the cell of claim 8.

10. A power tool comprising the battery of claim 9.

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