KR102332285B1 - Manufacturing method of copper busbar with improved heat generation - Google Patents

Abstract

The present invention relates to a method for manufacturing a copper bus bar with improved heat generation. More specifically, it is made by temper rolling the copper bus bar at a reduction ratio of 1.5 to 7%. The copper bus bar manufactured through the above process has improved surface roughness and thickness variation through the process of temper rolling. It shows an effect of improving heat generation due to a reduction of contact resistance of s connection part during the energization process.

Description

Manufacturing method of copper busbar with improved heat generation {MANUFACTURING METHOD OF COPPER BUSBAR WITH IMPROVED HEAT GENERATION}

The present invention relates to a method of manufacturing a copper bus bar with improved exothermicity, and more particularly, copper having improved heat generation due to a decrease in contact resistance of a connection part during energization because the surface roughness is improved through the process of temper rolling. It relates to a method for manufacturing a bus bar.

In general, a bus bar made of a thick plate such as copper or aluminum is used for a switchboard, a distribution board, and a control panel to connect between terminals. A machining operation such as cutting or bending or punching a plurality of fastening holes is required for connection with the member.

In the past, cables have been used a lot as a medium for transmitting electrical energy, but recently, a bus bar having the advantage of being able to transmit more electrical energy with a conductor of the same volume is widely used as an alternative to the cable. Such a bus bar must have excellent electrical conductivity, and high strength and durability must be secured.

Busbars are used in distribution boards or switchboards for industrial use that require the installation of a large-capacity electric energy transmission system and for small-scale households. Aluminum clad material is mainly used. Considering the electrical properties of the metal, copper is the most used.

However, when the conventional copper bus bar made of copper is applied to a switchgear, etc., the contact resistance increases due to a decrease in the adhesion of the conductor connection of the power device, and the switchgear operates due to excessive heat at the connection part due to heat generated. It causes a stop or breakdown, and in severe cases, it leads to a fire, and 4 to 5,000 fire accidents occur every year, so a solution is urgently needed.

Korean Patent Registration No. 10-0629445 (September 21, 2006) Korea Patent Publication No. 10-2021-0023051 (2021.03.04)

It is an object of the present invention to provide a method for manufacturing a copper bus bar in which heat generation is improved due to a decrease in contact resistance of a connection part during an energization process because the surface roughness is improved through the process of temper rolling.

An object of the present invention is achieved by providing a method for manufacturing a copper bus bar with improved exothermic property, characterized in that the copper bus bar is subjected to temper rolling at a reduction ratio of 1.5 to 7%.

According to a preferred feature of the present invention, the temper rolling shall consist of a reduction ratio of 1.5 to 5%.

According to a more preferred feature of the present invention, the temper rolling is to be performed in the order of initial rolling (break down), intermediate rolling and finishing rolling (refining finish rolling).

According to a more preferred feature of the present invention, after the initial rolling, intermediate rolling and finish rolling, annealing at a temperature of 500 to 650° C. for 1 to 5 minutes is performed.

It is also an object of the present invention to provide a copper busbar manufactured by the above manufacturing method, wherein the arithmetic mean roughness (Ra) is 0.1 to 0.2 micrometers, and the ten-point average roughness (Rz) is 3 to 4.5 micrometers. can also be achieved by

The method for manufacturing a copper bus bar with improved heat generation according to the present invention has an excellent effect of providing a copper bus bar with improved heat generation due to a reduction in contact resistance of the connection part during energization because the surface roughness is improved through the process of temper rolling. indicates

1 is a schematic diagram showing a state in which a decrease in adhesion of a connection portion occurs due to the roughness of the surface of the bus bar.
FIG. 2 is a photograph showing a state in which local melting occurred in the copper bus bar and an accident of the electric power device was induced.
3 is a graph showing the thickness variation of a copper bus bar (thickness 10mm×width 80mm) measured in the related art.
4 is a photograph showing the result of observation using an optical microscope after the conventional bus bar connection part is manufactured.
5 is a graph showing the conventional measurement of the surface roughness of the bus bar.
6 is a graph showing the thickness deviation of the copper bus bars manufactured according to Example 1 and Comparative Example 1 of the present invention.
7 is a graph showing the measurement of the roughness (Ra, Rz) of the copper bus bar prepared in Example 1 and Comparative Example 1 of the present invention.
8 is a photograph showing the cross-section of the copper bus bar prepared in Example 2 and Comparative Example 1 of the present invention taken with a scanning electron microscope (SEM).
9 to 11 are graphs showing the temperature rise behavior during energization of the copper busbars prepared in Examples 1 to 2 and Comparative Example 1 of the present invention.
12 is a photograph showing the state of measuring the contact resistance of the connection portion of the copper bus bars manufactured in Examples 1 to 2 and Comparative Example 1 of the present invention while energized.
13 is a flowchart showing a process of surface-treating the surface of the copper busbar with a sulfuric acid solution.

Hereinafter, a preferred embodiment of the present invention and the physical properties of each component will be described in detail, which is intended to describe in detail enough that a person of ordinary skill in the art to which the present invention pertains can easily carry out the invention, This does not mean that the technical spirit and scope of the present invention is limited.

The method for manufacturing a copper bus bar with improved exothermicity according to the present invention consists of a process of improving the surface roughness by temper rolling the copper bus bar, which is made by temper rolling the copper bus bar at a reduction ratio of 1.5 to 7%, and further Preferably, it is made by temper rolling the copper bus bar at a reduction ratio of 1.5 to 5%.

In general, as shown in FIG. 1 below, as shown in FIG. 1 below, as shown in FIG. 2 below, as shown in FIG. Similarly, it leads to local melting of the copper busbar, which causes the operation of power equipment to stop or a fire accident.

The contact resistance (Contact R) is expressed as the sum of the convergence resistance (R) and the boundary resistance (Interface R, resistance by the oxide film), and plays an important role in increasing the amount of heat as expressed in Equation 1 below.

<Equation 1>

Accordingly, the thickness deviation of the copper bus bar (10mm thickness × 80mm width) was precisely investigated and analyzed and shown in Fig. 3 below. was used to measure the behavior of

In addition, in FIG. 4 below, after manufacturing the connection part of the copper bus bar, the result of observation using an optical microscope is shown, and a gap of 12.019 micrometers was observed.

In addition, the surface roughness and behavior of the copper bus bar were investigated and shown in FIG. 5 below. {However, the surface roughness and behavior of the copper bus bar were measured by Left-Middle-Right using a scan length of 15 mm (longest), Scan speed is 0.5mm/s.}

As shown in FIGS. 3 to 5 below, it can be seen that the conventionally manufactured copper bus bar has a wide variation in thickness, a gap between the connection parts, and a surface roughness.

The thickness deviation, gap and surface roughness of the connection part can be eliminated by temper rolling the copper bus bar at a reduction ratio of 1.5 to 7%, more preferably, temper rolling at a reduction ratio of 1.5 to 5%, as described above.

At this time, the temper rolling is preferably performed in the order of initial rolling, intermediate rolling and finish rolling. After the initial rolling, intermediate rolling and finish rolling, annealing at a temperature of 500 to 650° C. for 1 to 5 minutes is performed. It is more preferable to be

As described above, while the temper rolling is performed in the order of initial rolling, intermediate rolling and finish rolling, the process of annealing at a temperature of 500 to 650 ° C. for 1 to 5 minutes after initial rolling, intermediate rolling and finish rolling is performed. By relieving the stress accumulated inside the material, it is possible to secure optimum electrical conductivity properties.

In addition, the copper bus bar, which has been subjected to the temper rolling process as described above, is surface-treated with a sulfuric acid solution to form a porous softening layer, thereby improving the surface resistance and further lowering the exothermicity.

At this time, the surface treatment of the copper bus bar with the sulfuric acid solution includes a degreasing step (S101) of degreasing the surface, a washing step (S103) of washing the degreased copper bus bar through the degreasing step (S101), and the washing step ( An electrolytic treatment step (S105) of immersing the copper bus bar washed through S103) in a sulfuric acid solution and applying a voltage, and a washing and drying step of washing and drying the surface-treated copper bus bar through the electrolysis treatment step (S105) ( S107).

The degreasing step (S101) is to improve the efficiency of the electrolysis treatment step by removing the oil and fat components remaining on the surface of the copper bus bar, and a component capable of removing the oil and fat component without damaging the copper bus bar. As long as it is not particularly limited, any one can be used, but it is preferable to use an electrolytic degreasing solution containing caustic soda and blue soda, and it consists of a process of immersion in the electrolytic degreasing solution composed of the above components for 30 to 60 seconds. it is preferable

In this case, it is preferable that the caustic soda is 30 g/L, and the blue soda is 10 g/L.

The washing step (S103) is a step of removing the degreasing solution or foreign substances remaining on the surface of the copper bus bar degreased through the degreasing step (S101). It is made by washing 2-3 times with a furnace, and it is preferable to proceed with washing by irradiating ultrasonic waves after immersion in purified water.

The electrolysis treatment step (S105) is a step of immersing the copper bus bar washed through the washing step (S103) in a sulfuric acid solution and applying a voltage, and the mass concentration of the copper bus bar washed through the washing step (S103) is It consists of a process of applying a voltage of 20 to 35 V in a state of being immersed in a sulfuric acid solution of 8 to 10% and 35 to 45° C. for 30 to 120 seconds. A porous softening layer having a thickness of 5 to 20 micrometers is formed on the surface of the copper busbar.

When the porous softening layer is formed with a thickness of 5 to 20 micrometers on the surface of the copper bus bar through the electrolytic treatment step (S105), the porous softening layer on the surface of the copper bus bar serves as a cushion when forming the connection part. Since the adhesion is remarkably improved, it is possible to provide a copper busbar with lower exothermicity.

At this time, when the thickness of the porous softening layer is less than 5 micrometers, the cushioning role is insignificant, and the contact resistance improvement effect is insignificant. When the thickness of the porous softening layer exceeds 20 micrometers, the contact resistance improvement effect is greatly improved The porous softening layer may be peeled off during handling, which is not preferable.

The washing and drying step (S107) is a step of washing and drying the surface-treated copper bus bar through the electrolysis treatment step (S105). The remaining sulfuric acid solution is washed 2-3 times with purified water, and then dried using a hot air dryer.

Hereinafter, a method for manufacturing a copper bus bar having improved heat generation according to the present invention and physical properties of a copper bus bar manufactured through the manufacturing method will be described with reference to examples.

<Example 1>

A copper bus bar having a thickness of 10 mm, a width of 80 mm, and a length of 1000 mm was temper-rolled at a reduction ratio of 3% to prepare a copper bus bar with improved exothermicity.

<Example 2>

A copper bus bar with a thickness of 10 mm, a width of 80 mm, and a length of 1000 mm is immersed in a degreasing solution (caustic soda 30 g/L, containing 10 g/L of the clarification soda) for 45 seconds to remove the oil and fat components, and the copper The bus bar was washed with purified water, and the washed copper bus bar was immersed in a sulfuric acid solution at 40° C. with a mass concentration of 9% for 75 seconds, and a voltage of 30 V was applied to form a porous softened layer, and the porous softened layer was formed. The formed copper bus bar was washed with purified water and dried with a hot air dryer to prepare a copper bus bar with improved exothermicity.

<Example 3>

The copper bus bar prepared in Example 1 was immersed in a degreasing solution (containing caustic soda 30 g/L, the clarification soda 10 g/L) for 45 seconds to remove the oil and fat component, and the copper bus bar from which the oil component was removed was washed with purified water. After immersing the washed copper busbar in a sulfuric acid solution at 40°C having a mass concentration of 9% for 75 seconds, a voltage of 30V was applied to form a porous softened layer, and the copper busbar on which the porous softened layer was formed was washed with purified water. A copper bus bar with improved exothermicity was manufactured by washing with a hot air dryer and drying with a hot air dryer.

<Comparative Example 1>

A copper busbar having a thickness of 10 mm, a width of 80 mm, and a length of 1000 mm.

The thickness variation of the copper bus bars manufactured in Example 1 and Comparative Example 1 was measured and shown in FIG. 6 below.

As shown in FIG. 6 below, it can be seen that in Example 1 of the present invention, the thickness variation between the central portion and the corner portion of the copper bus bar was reduced by temper rolling at a reduction ratio of 3%.

In addition, the roughness (Ra, Rz) of the copper bus bar prepared in Example 1 and Comparative Example 1 was measured and shown in FIG. 7 below.

As shown in FIG. 7 below, it can be seen that the copper bus bar manufactured in Example 1 of the present invention has reduced illuminance.

In addition, the cross-sections of the copper bus bars prepared in Example 2 and Comparative Example 1 were photographed with a scanning electron microscope (SEM), and are shown in FIG. 8 below. As shown in FIG. 8 below, it can be seen that the copper bus bar manufactured in Example 2 of the present invention has a porous softening layer with a thickness of about 10 micrometers formed on the surface.

In addition, the hardness of the copper bus bars prepared in Examples 1 to 2 and Comparative Example 1 was measured and shown in Table 1 below.

{However, the hardness was measured with a micro Vickers hardness tester, and three places on the left, center and right side of the prepared copper bus bar were measured, and a total of 7 measurements were performed and the average value was expressed.}

<Table 1>

As shown in Table 1, it can be seen that the copper busbars prepared in Examples 1 and 2 of the present invention have lower hardness than the copper busbars of Comparative Example 1, and in particular, as in Example 2, a porous softening layer is formed. It can be seen that the hardness of the copper bus bar is significantly lowered.

The temperature rise behavior of the copper busbars prepared in Examples 1 and 2 and Comparative Example 1 during energization was measured and shown in FIGS. 9 to 11 and Table 2 below.

{However, the behavior of temperature rise during energization was measured on six surfaces of the copper bus bar, under the condition of a test current of 1400A (rated current), and tested with a DC Power Supply (max. 3000A), using an Agilent 34970A. measured.}

<Table 2>

As shown in Table 2 and FIGS. 9 to 11 below, it can be seen that the copper busbars manufactured through Examples 1 and 2 of the present invention have a significantly reduced temperature during energization compared to the copper busbars of Comparative Example 1.

In addition, the contact resistance of the connecting portion of the copper bus bar prepared in Examples 1 to 2 and Comparative Example 1 during energization was measured and shown in Table 3 below.

{However, the contact resistance of the connection part during energization was measured using a voltage measuring device by connecting the copper bus bar as shown in FIG. 12 below at a test current of 10A.}

<Table 3>

As shown in Table 3, it can be seen that the copper bus bars manufactured in Examples 1 and 2 of the present invention significantly reduced the contact resistance of the connection part during energization compared to the copper bus bar of Comparative Example 1.

Accordingly, the method for manufacturing a copper bus bar with improved heat generation according to the present invention provides a copper bus bar with improved heat generation due to a reduction in contact resistance of a connection portion during energization because the surface roughness is improved through the temper rolling process. .

S101; degreasing step
S103; washing step
S105 ; Electrolysis treatment step
S107; washing and drying step

Claims (5)

It is made by temper rolling the copper bus bar at a reduction ratio of 1.5 to 7%,
The temper rolling is performed in the order of initial rolling (break down), intermediate rolling and finishing rolling (refining finish rolling),
After the initial rolling, intermediate rolling and finish rolling, annealing at a temperature of 500 to 650° C. for 1 to 5 minutes is performed.
The method according to claim 1,
The method of manufacturing a copper bus bar with improved exothermicity, characterized in that the temper rolling is performed at a reduction ratio of 1.5 to 5%.
delete delete A copper bus bar manufactured by the manufacturing method according to any one of claims 1 to 2, wherein the arithmetic mean roughness (Ra) is 0.1 to 0.2 micrometers, and the ten-point average roughness (Rz) is 3 to 4.5 micrometers. .

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