Resistance alloy for shunt resistor, application of resistance alloy to shunt resistor, and shunt resistor using resistance alloy

Abstract

The present invention provides a resistance alloy for a shunt resistor, an application of the resistance alloy to the shunt resistor, and a shunt resistor using the resistance alloy. In a resistor for current detection such as a shunt resistor, a low TCR can be maintained, a low resistivity can be achieved, and a small thermoelectric potential to copper can be achieved. The resistance alloy is used for a shunt resistor for current detection, and the manganese in the resistance alloy is 4.5 to 5.5% by mass, the silicon is 0.05 to 0.30% by mass, the iron is 0.10 to 0.30% by mass, and the remainder is composed of copper, and the resistivity is 15 to 25 μΩ·cm.

Description

Technical Field

[0001] The present invention relates to a resistance alloy for a shunt resistor, application of the resistance alloy to the shunt resistor, and a shunt resistor using the resistance alloy. Background Art

[0002] As the resistance alloy used for shunt resistors including electrodes and resistors for current detection, there are copper-manganese alloys (copper-manganese-nickel alloys, etc.), copper-nickel alloys, nickel-chromium alloys, iron-chromium alloys, etc. In order to obtain high detection accuracy, the resistance alloys of shunt resistors mostly use copper-manganese alloys with low temperature coefficient of resistance (hereinafter also referred to as "TCR") and small thermoelectric electromotive force relative to copper. As a common copper-manganese alloy (copper-manganese-nickel alloy), there is a copper-manganese-tin alloy with a resistivity of 29μΩ·cm.

[0003] It is assumed that a small and low-resistance shunt resistor is designed using this resistance alloy. In this case, the plate thickness needs to be increased to reduce resistance, and if this is done, the workability such as stamping will be reduced. On the other hand, if the distance between electrodes is reduced to reduce resistance, the contribution of the TCR of the electrode part as a whole of the shunt resistor becomes larger. That is, the TCR (product TCR) of the shunt resistor as a whole increases.

[0004] It is assumed that a small and low-resistance shunt resistor is designed using a resistance material with a low resistance value, such as a copper-nickel alloy with a resistivity of 20 μΩ·cm. In this case, the TCR of the resistance alloy is large, and the product TCR also becomes large. In addition, the thermoelectric potential to copper is also large, so the use and use conditions of the resistance alloy as a shunt resistor are limited.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Publication No. 2007-329421

[0008] Patent Document 2: International Publication No. WO 2016 / 111109 Summary of the invention

[0009] Technical Problems to be Solved by the Invention

[0010] In recent years, there is a demand for current detection resistors to be used for detecting large currents such as 1000 A. To cope with this, the resistance value of the shunt resistor is being reduced to 100 μΩ, 50 μΩ, 25 μΩ, and 10 μΩ.

[0011] When the above-mentioned resistance alloy is used to form a shunt resistor (resistor for current detection), copper electrodes are welded to both ends of the resistor. Copper has a TCR as high as about 4000ppm / K (25-100°C). In the case of miniaturizing or reducing the resistance of the shunt resistor, the TCR of such a copper electrode contributes to the increase in the proportion of the resistance value of the shunt resistor. Therefore, the TCR of the shunt resistor increases, and the accuracy of current detection deteriorates.

[0012] Patent Document 1 discloses a technique for adjusting TCR using the shape of a resistor. However, there is a problem that the actual resistance of the resistor increases due to processing of the electrodes. In addition, there are problems such as difficulty in processing and adjusting when miniaturizing the resistor.

[0013] In addition, when the shunt resistor is made low-resistance and small-sized, there is also a problem that the TCR of the resistor increases and the detection accuracy decreases. In addition, it is also necessary to ensure the reliability of the current detection device.

[0014] Furthermore, the thickness and width of the shunt resistor may be fixed due to product specifications, which may cause the following problems.

[0015] Fig.10 This is a perspective view of a shunt resistor in which the distance between electrodes is changed. Here, a lift structure in which the resistor body is lifted relative to the electrode end is described as an example. Fig.10 (a) is a perspective view showing a configuration example of a shunt resistor in which a distance L103 between electrodes 1115a and 115b connected to wirings 121a and 121b (distance between electrodes = length of resistor 111) is shortened in the shunt resistor X1. Fig.10 (b) is a perspective view showing a configuration example of a shunt resistor in which the inter-electrode distance L113 between electrodes 115a and 115b connected to wirings 121a and 121b is lengthened in the shunt resistor X2. In addition, L101, L102, L111, and L112 are widths corresponding to the widths that can be changed in each shunt resistor.

[0016] The following reference Fig.10 (a) and (b) are described below. Fig.10 (a) Fig.10 (b) is also used for explanation in the following embodiments of the present invention.

[0017] 1) When the size of the electrode of the shunt resistor is constant, the thickness of the resistor body needs to be increased in order to reduce the resistance value of the shunt resistor. However, if the thickness of the resistor body is increased, there is a problem that the cut portion collapses or cannot maintain a beautiful shape when performing stamping (punching).

[0018] 2) With Fig.10 Compared with the structure of the shunt resistor shown in (b), that is, the structure in which the distance L113 between electrodes is long (the electrode widths L111 and L112 of the raised portion are relatively short), as shown in FIG. Fig.10 As shown in (a), the electrode widths L101 and L102 of the raised portions of the electrodes are relatively lengthened and the distance L103 between the electrodes is shortened (making the length of the resistor 111 shorter), thereby reducing the resistance value of the shunt resistor X1. Therefore, a shunt resistor with a low resistance value can be realized. However, since the lengths of the electrodes 115a and 115b are relatively large relative to the length of the resistor 111, the TCR of the shunt resistor X1 becomes higher due to the influence of the TCR of copper as the electrode material. That is, in Fig.10 middle, Fig.10 The structure of (a) is Fig.10 Compared with the structure of (b), as shown by the arrows, the copper electrodes 115a and 115b are relatively larger than the resistor 111, so there is a problem that the TCR becomes higher.

[0019] In addition, if Fig.10 As shown in (a), if the length L103 of the resistor 111 is shortened, it becomes difficult to weld the resistor 111 to the electrodes 115a and 115b. Therefore, there is a limit to the low resistance of the shunt resistor X1. That is, since welding requires a certain width margin, if the length of the resistor 111 is made too short, the actual resistor part will become smaller. For example, if you want to weld the resistor to the electrode using electron beam welding, the width of the welding mark needs to be considered. Therefore, there is a limit to the processing size in the process of shortening the length of the resistor.

[0020] 3) As another method of reducing the resistance value of the shunt resistor, it is conceivable to reduce the resistivity of the resistor alloy constituting the resistor.

[0021] For example, as a resistor alloy with a low TCR and a low resistivity, there is a Cu-7Mn-2.3Sn alloy. The resistivity is 29μΩ·cm, which is not low enough. As a resistor alloy with a resistivity of 20μΩ·cm, there is a Cu-Ni alloy, but the TCR performance is about 330ppm·K, which is not excellent. In addition, the thermoelectric potential of copper increases, which has a great influence on the accuracy of current detection.

[0022] Patent Document 2 discloses a resistance alloy consisting of a Cu alloy containing Cu, 6.20 mass % to 7.40 mass % Mn, and 0.15 mass % to 1.5 mass % Si, wherein the absolute value of TCR at 25° C. to 150° C. is 15 ppm / K or less.

[0023] Thus, the absolute value of TCR can be reduced in a wide temperature range. However, although Patent Document 2 discloses that a low TCR is achieved, it does not disclose that the resistivity and the thermoelectromotive force of copper are also reduced. This will be described later.

[0024] An object of the present invention is to achieve a low resistivity and a small thermoelectromotive force to copper while maintaining a low TCR in a resistor for current detection such as a shunt resistor.

[0025] Another object of the present invention is to provide a resistance alloy used for such a shunt resistor.

[0026] Technical solutions for solving technical problems

[0027] According to one aspect of the present invention, there is provided a resistance alloy, which is a copper-manganese resistance alloy used for a shunt resistor for current detection, wherein manganese accounts for 4.5 to 5.5% by mass, silicon accounts for 0.05 to 0.30% by mass, iron accounts for 0.10 to 0.30% by mass, and the remainder is copper, and the resistivity is 15 to 25 μΩ.

[0028] In the above resistance alloy, it is characterized by that the TCR is 100×10 -6 / K or less (0~100×10 -6 range).

[0029] In addition, in any of the above-mentioned resistance alloys, the thermoelectromotive force with respect to copper is within ±1 μV / K.

[0030] This can reduce the TCR value of the shunt resistor formed of the copper electrode, for example, and reduce the TCR and the thermoelectromotive force to copper.

[0031] Furthermore, the present invention is application of any of the above-described resistance alloys to a resistor element of a shunt resistor used in a current detection device.

[0032] In addition, the present invention is a shunt resistor, which is a shunt resistor for current detection including a resistor body and an electrode, wherein the resistor body is formed of a resistor alloy, wherein the manganese content of the resistor alloy is 4.5 to 5.5% by mass, the silicon content is 0.05 to 0.30% by mass, the iron content is 0.10 to 0.30% by mass, and the remainder is copper, and the resistivity is 15 to 25 μΩ.

[0033] In addition, the present invention is a shunt resistor for current detection, which includes a resistor body and an electrode, wherein the resistor body is formed by a resistor alloy, the manganese in the resistor alloy is 4.5-5.5 mass %, the silicon is 0.05-0.30 mass %, the iron is 0.10-0.30 mass %, and the remainder is copper, and the resistivity is 15-25 μΩ.

[0034] This specification includes the disclosure of Japanese Patent Application No. 2020-145278 which is the basis of priority for the present invention.

[0035] Effects of the Invention

[0036] If the resistance alloy of the present invention is used, the TCR of the shunt resistor used in the current detection device can be reduced, and a low resistivity and a small thermoelectromotive force to copper can be achieved.

[0037] Furthermore, by using the resistance alloy of the present invention, the reliability of current detection by the shunt resistor can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a phase diagram of a quaternary alloy containing copper and a manganese-iron-silicon resistor alloy for a resistor according to the present embodiment.

[0039] Figure 2 It is a figure which shows the shape of the element for evaluation of the resistance alloy for resistors of this embodiment.

[0040] Figure 3 1 is a graph showing the relationship between the resistivity and TCR of the resistance alloy according to the present embodiment, and is a graph showing the values ​​corresponding to Samples 1 to 6 of the Cu-Mn alloys (including samples to which Fe is added) in Table 1.

[0041] Figure 4 It is a graph showing the relationship between the Fe composition of the resistance alloy of the present embodiment and the thermoelectromotive force to copper, and is a graph showing the values ​​corresponding to Sample 2 and Samples 4 to 6 of the Cu-Mn alloy (including samples to which Fe is added) in Table 1.

[0042] Figure 5 It means to use Figure 2 The diagram shows the analysis results of the evaluation element subjected to a high temperature storage test using XRD (X-ray diffractometer) when Si was added to the resistance alloy.

[0043] Figure 6 It means to use Figure 2 The graph shown is a graph of a high temperature storage test of an evaluation element to investigate the influence of Si addition, and is a graph showing the relationship between the amount of Si addition and the diffraction intensity of the 111 plane of Cu2O (vertical axis: counts).

[0044] Figure 7 This is a diagram showing the relationship between TCR and resistivity of the resistance material of the resistance alloy according to the present embodiment.

[0045] Figure 8 (a) is a perspective view showing a configuration example of a shunt resistor using the alloy for a resistor according to the second embodiment of the present invention. Figure 8 (b) is a top view and a side view of the shunt resistor. Figure 8 Dimensions (mm) are shown in (b).

[0046] Fig. 9A It is a diagram showing an example of a manufacturing process of a shunt resistor according to a third embodiment of the present invention.

[0047] Fig. 9B is a diagram showing an example of a manufacturing process of a shunt resistor according to a third embodiment of the present invention, and Fig. 9A .

[0048] Fig. 9C is a diagram showing an example of a manufacturing process of a shunt resistor according to a third embodiment of the present invention, and Fig. 9B .

[0049] Fig.9D is a diagram showing an example of a manufacturing process of a shunt resistor according to a third embodiment of the present invention, and Fig. 9C .

[0050] Fig.9E is a diagram showing an example of a manufacturing process of a shunt resistor according to a third embodiment of the present invention, and Fig.9D .

[0051] Fig.9F 1 is a cross-sectional view showing a shunt resistor manufactured by the manufacturing process of the shunt resistor according to the third embodiment of the present invention.

[0052] Fig.10 This is a perspective view when the distance between electrodes is changed in the shunt resistor. DETAILED DESCRIPTION

[0053] The inventors have found that a resistor material using a Cu-Mn-Si alloy as described in Patent Document 2 can maintain a low TCR (100×10 -6 / K or less), and can achieve a low resistivity (for example, 15 to 25 μΩ·cm).

[0054] Furthermore, the composition and the like can be adjusted so as to have a small thermoelectromotive force with respect to copper.

[0055] Hereinafter, a resistance alloy for a shunt resistor, a shunt resistor using the resistance alloy, and the like according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0056] First, the inventors' considerations regarding the present invention will be briefly described.

[0057] 1) The inventors' focus is that in order to compensate for the high positive TCR contribution of copper used as an electrode, it is important to mix a resistor alloy showing a negative TCR with the resistor body. However, there are few reports on resistor alloys with a large negative TCR.

[0058] 2) Although there are copper-nickel alloys with low TCR and excellent long-term stability, the thermoelectric potential of these alloys to copper is as large as 40 μV / K. Therefore, the detection accuracy of shunt resistors used in current detection devices for large currents is reduced due to the Peltier effect.

[0059] 3) As an alloy having a negative TCR, there is a nickel-chromium alloy. However, the resistivity of the nickel-chromium alloy is more than twice that of the copper-nickel alloy and the copper-manganese alloy. Therefore, it is difficult to achieve a low resistance of the shunt resistor.

[0060] In the present embodiment, a resistance alloy for a resistor element capable of achieving a low resistivity (for example, 15 to 25 μΩ·cm) is provided.

[0061] In addition, it is shown that the -6 / K or less), and sufficiently small thermoelectromotive force against copper (1.0μV / K or less).

[0062] (First Embodiment)

[0063] The following embodiments of the present invention will be described in detail.

[0064] The alloy of the present embodiment is a resistance alloy having a low TCR, and is a quaternary alloy composed of copper-manganese-silicon-iron. This resistance alloy can be used as a resistance material of a shunt resistor.

[0065] Figure 1 This is a phase diagram of a quaternary alloy including copper-manganese-silicon-iron alloy for resistors according to the present embodiment.

[0066] Here, the mass fraction of copper is shown on the upper left axis, and the mass fraction of silicon + iron is shown on the upper right axis. On the other hand, the mass fraction of manganese is shown on the bottom axis.

[0067] Figure 1The black region R that provides the characteristics of the resistance alloy of the present invention is shown in the figure. The mass fraction of manganese in the region R is 4.5% to 5.5%, and the mass fraction of silicon + iron in the region R is 0.15% to 0.60%. More specifically, the mass fraction of silicon is 0.05% to 0.30%, and the mass fraction of iron is 0.10% to 0.30%. The remainder is copper.

[0068] A typical value of manganese is 5.0 mass%. A typical value of silicon is 0.15 mass%. A typical value of iron is 0.2 mass%. The remainder is copper.

[0069] Figure 2 It is a figure which shows the shape of the element for evaluating the alloy for resistors which concerns on embodiment of this invention.

[0070] like Figure 2 As shown, the evaluation element X of the alloy for resistors has electrodes (portions through which current flows) 1 and 3 at both ends, a resistor 5 extending between the electrodes 1 and 3, and voltage detection portions 7 and 9 located closer to the center than the two ends of the resistor 5. The distance between the electrodes 1 and 3 is 50 mm, and the distance between the voltage detection portions 7 and 9 is 20 mm.

[0071] Next, an example of a process for producing an evaluation sample will be briefly described.

[0072] 1) Weigh the raw materials.

[0073] 2) Dissolve the material in 1).

[0074] 3) Use a cold rolling mill to make the material into strip of specified thickness.

[0075] 4) Heat treatment is performed in a vacuum gas replacement furnace at 500 to 700°C for 1 to 2 hours under a N2 atmosphere.

[0076] 5) Made from strip by stamping Figure 2 An element for evaluating the shape of.

[0077] 6) Heat treatment (low temperature heat treatment) is performed in a vacuum gas replacement furnace at 200 to 400°C for 1 to 4 hours under N2 atmosphere.

[0078] The mass fractions of the alloy components in the region R are adjusted to each other so that the resistance alloy has the following characteristics (appropriate conditions).

[0079] (Appropriate conditions)

[0080] 1) The resistivity is 15 μΩ·cm or more and 25 μΩ·cm or less.

[0081] 2) TCR is based on 25°C and 100×10 -6 / K or less (0~100×10 -6 / K)

[0082] 3) The thermal electromotive force of copper is within ±1μV / K.

[0083] As described above, in order to solve the above problems, the present invention provides a low resistivity (about 20 μΩ·cm: 15 to 25 μΩ·cm range), a low TCR (100×10 -6 / K or less) and a resistance alloy with a small thermal electromotive force to copper (within ±1μV / K).

[0084] In this specification, a shunt resistor that is small means that the chip size is 6.3×3.1 mm or less, and a low resistance means that the product has a resistance of 0.5 mΩ or less.

[0085] (Detailed description of resistance alloy specimen)

[0086] Various resistance alloys as shown below were produced.

[0087] Table 1 shows the compositions and properties of these resistance alloys.

[0088] [Table 1]

[0089]

[0090] Table 1 is a table showing the composition of the resistance alloys including the resistance alloys of the present embodiment (Examples 1 and 2), Comparative Example 1 (Cu-14Ni), and Comparative Example 2 (Cu-Mn-Sn alloy), and their electrical properties (resistivity, TCR, and thermoelectromotive force to copper). In addition, Table 1 also includes samples 1 to 7 for the purpose of verifying and confirming the composition range (containing range) of the resistance alloy of the present invention.

[0091] The resistivity of the resistor material was 15 to 25 μΩ·cm (15 to 25 μΩ·cm) for the samples of Examples 1 and 2, which were commercially available materials. The thermoelectromotive force (0 to 100° C.) to copper was 0.2 μV / K or less, which fully satisfied the appropriate conditions.

[0092] By examining the data shown in Table 1, especially the values ​​of Examples 1 and 2 and Samples 1 to 7, the following can be understood.

[0093] 1) Maintaining low resistivity while adjusting other properties

[0094] When compared with the results of samples 1 to 3 containing neither Fe nor Si, the CuMn alloy can achieve the appropriate conditions (property requirements) of the present invention for the resistivity and TCR characteristics, but the thermoelectromotive force to copper may exceed 1 μV / K. Therefore, it is necessary to add an element that reduces the thermoelectromotive force to copper and does not deteriorate (increase) the TCR.

[0095] 2) Regarding the improvement of TCR, etc. and the effect of Fe addition

[0096] If other elements, in this case Fe, are added to the CuMn alloy, there is a tendency that the TCR decreases but the resistivity increases. Therefore, in order to evaluate the effect of reducing the TCR, both the resistivity and the TCR need to be considered.

[0097] Figure 3 This is a graph showing the relationship between the resistivity and TCR of a Cu-Mn alloy. The values ​​corresponding to Samples 1 to 6 of the Cu-Mn alloys (including samples to which Fe is added) in Table 1 are shown.

[0098] exist Figure 3 The values ​​of Cu-Mn alloy and Cu-5Mn-Fe alloy are shown in FIG. In each curve in the figure, the composition of Mn and Fe is shown by numerical values.

[0099] like Figure 3 As shown, it can be seen that in the Cu-Mn alloy, as the composition of Mn increases to 5.0 mass % and 5.5 mass %, the TCR can be gradually reduced.

[0100] In addition, it can be evaluated that in the Cu-5Mn-Fe alloy, as the Fe composition increases, the TCR increases (deteriorates). In particular, when the Fe composition exceeds 0.5 mass%, the TCR increases sharply to 1.0 mass%.

[0101] However, it is also known that if the Fe composition is less than 0.5 mass %, for example, about 0.2 mass %, the TCR does not increase sharply.

[0102] In any range, TCR is 100×10 -6 / K or less.

[0103] Figure 4 This is a graph showing the relationship between the composition of Fe and the thermoelectromotive force to copper. The values ​​corresponding to Sample 2 and Samples 4 to 6 of the Cu-Mn alloy (including samples to which Fe is added) in Table 1 are shown.

[0104] From sample 4 (Fe: 0.2 mass%), it can be seen that even a small amount of Fe addition has the effect of significantly reducing the thermoelectromotive force to copper. In addition, from the values ​​of samples 2, 4-6, it can be seen that by adding 0.1 to 0.3 mass% of Fe, the thermoelectromotive force to copper can be brought within the range of about ±0.5 μV / K. Figure 3 As for the effect of Fe addition on TCR, the results of samples 2 and 4-6 show that if Fe addition is up to 0.5 mass %, TCR can be increased to 100×10 -6 / K or less.

[0105] As described above, if a resistance alloy to which 0.10 to 0.30 mass % of iron is added is used in a Cu-Mn alloy, the thermoelectromotive force to copper can be reduced to within ±1 μV / K and the TCR can be reduced to 100×10 -6 / K or less.

[0106] 3) Effect of Si addition

[0107] In a Cu-Mn alloy material, when the composition is close to 100% Cu, oxidation of Cu is expected to become a problem. Therefore, it is also important to suppress oxidation of Cu.

[0108] use Figure 2 The evaluation elements shown were subjected to a heat resistance test on the samples of Examples 1 and 2 and Sample 4 (the samples of Examples 1 and 2 were added with Si) in Table 1.

[0109] Figure 5 This is a graph showing the results of XRD (X-ray diffraction) analysis based on Si addition, and is the measurement result of the sample after 3000 hours of high temperature storage test at 175°C. Figure 5 The upper side shows the measurement results of Example 2, Example 1, and Sample 4 in sequence.

[0110] in addition, Figure 6 This is a graph showing the Si composition dependence of the Si addition amount and the diffraction intensity (vertical axis: counts) of the 111 plane of Cu2O when the same high-temperature storage test was performed.

[0111] From the XRD data after high temperature placement test ( Figure 5 , Figure 6 ) shows that the addition of Si inhibits the generation of Cu2O. That is, the peak value of Cu2O ( Figure 5 The × mark indicates that the peak value of Cu is smaller as the amount of Si added increases. The ● mark indicates the peak value of Cu as a reference.

[0112] This phenomenon is presumably due to the effect of suppressing the oxidation of Cu caused by the formation of Si oxide on the material surface of the resistance alloy due to the addition of Si.

[0113] Figure 7 This is a graph showing the relationship between the TCR and resistivity of a resistor material. Figure 4 The corresponding characteristic diagram. Figure 7 The values ​​of Cu-Mn and Cu-5Mn-0.2Fe-Si (Sample 4, Example 1, Example 2) are shown in

[0114] like Figure 7 As shown, regarding the effect on TCR, it is known from the results of Examples 1, 2 and Sample 4 that TCR does not increase when the amount of Si added is about 0.2 mass %. According to the inventors' experiments, the amount of Si added is preferably in the range of 0.05 to 0.30 mass %.

[0115] (Detailed description of effectiveness of the present invention)

[0116] The effectiveness of the present invention will be described in detail below.

[0117] The present invention is a resistance alloy, which is a resistance alloy of a shunt resistor for current detection, wherein Mn is 4.5-5.5 mass %, Fe is 0.10-0.30 mass %, Si is 0.05-0.30 mass %, and the remainder is Cu.

[0118] The resistivity of the resistance alloy is in the range of 15 to 25 μΩ·cm.

[0119] In addition, the TCR of this resistance alloy is 100×10 -6 / K(25-100℃)below.

[0120] In addition, the thermoelectromotive force of the resistance alloy with respect to copper is within ±1 μV / K.

[0121] The above characteristics make it suitable for a small and low-resistance shunt resistor, and a low TCR value can be achieved. The current detection accuracy of a current detection device using a shunt resistor becomes good, and the space of the current detection device can be saved by miniaturizing the shunt resistor.

[0122] (Second Embodiment)

[0123] Next, a second embodiment of the present invention will be described. Figure 8 (a) is a perspective view showing a configuration example of a shunt resistor using the alloy for a resistor according to the second embodiment of the present invention. Figure 8 (b) is a top view and a side view of the shunt resistor. Figure 8Dimensions (mm) are shown in (b).

[0124] Figure 8 The shunt resistor A shown in (a) and (b) has a structure in which a single-piece resistor body 11 is manufactured by punching or the like, and Cu electrodes 15a and 15b are butt-welded at both ends thereof.

[0125] The resistor 11 and the electrodes 15 a and 15 b can be joined by EB (electron beam) welding, LB (laser beam) welding, or the like. Figure 8 The shunt resistor A shown is a relatively large shunt resistor, and is sometimes made one by one. The material of the resistor body can use the material described in the first embodiment, which contains 4.5 to 5.5 mass % manganese, 0.10 to 0.30 mass % iron, 0.05 to 0.30 mass % silicon, and the remainder copper. In addition, the alloy described in the first embodiment can be used according to the purpose.

[0126] In order to confirm the effect of using the resistance alloy of the present invention in a shunt resistor product, a shunt resistor was produced using each resistor element of Example 1 and Comparative Example 2.

[0127] [Table 2]

[0128]

[0129] Table 2 is a table comparing Comparative Example 2 and Example 1, and is a table showing dimensions, resistance values, and TCR.

[0130] The outer dimensions of the shunt resistor are 6.3 mm × 3.1 mm, the thickness of the resistor body is 1 mm, and the nominal resistance value of the shunt resistor is 0.2 mΩ.

[0131] As shown in Table 2, the shunt resistor using the resistance alloy of Example 1 can reduce the resistivity compared to the case where the resistance alloy of Comparative Example 2 is used, even if the rated resistance value is the same, so the length of the resistor body can be increased from 2 mm to 3 mm. Fig.10 As described in (a), TCR can be reduced.

[0132] The shunt resistor of the present embodiment can ensure the degree of freedom in designing the shunt resistor by using a resistor having a relatively high resistivity.

[0133] In addition, by using a resistance alloy having a relatively high resistivity, the contribution of Cu used as an electrode to the TCR of the entire resistor can be relatively reduced. Therefore, a shunt resistor that effectively utilizes the characteristics of the resistance alloy can be realized.

[0134] Here, in the present embodiment, the TCR of the resistor material is adjusted to be on the negative side. Therefore, the TCR of the resistor itself joined with the copper electrode can be reduced.

[0135] In addition, Figure 8 The TCR was measured in the shunt resistor A having the structure and dimensions shown in (b). The TCR of the shunt resistor using Comparative Example 1 as the resistance material was 76ppm / K. In contrast, the TCR of the shunt resistor using Sample 1 was 50ppm / K. It can be seen that if the resistance alloy of this embodiment is used, the TCR can be improved to a direction close to 0.

[0136] (Third Embodiment)

[0137] Next, a third embodiment of the present invention will be described. This is an example in which a long strip of bonding material for bonding a resistor body and an electrode is prepared and cut by punching. This allows mass production of relatively small shunt resistors.

[0138] An example of such a manufacturing process is shown below. Figures 9A to 9F It is a diagram showing an example of a manufacturing process of the shunt resistor according to the present embodiment.

[0139] like Fig. 9A As shown, for example, a long flat plate-shaped resistor material 21, a long flat plate-shaped first electrode material 25a and a second electrode material 25b are prepared as the resistor material 21. The resistor material 21 uses the alloy material described in the first and second embodiments.

[0140] like Fig. 9B As shown, the first electrode material 25 a and the second electrode material 25 b are respectively disposed on both sides of the resistor material 21 .

[0141] Also like Fig. 9C As shown, for example, electron beams, laser beams, etc. are used for welding to form a flat plate (joined at L11 and L12). At this time, the irradiation position of the electron beam or the like is set to Fig. 9C (a) or Fig. 9C (b). Fig. 9C (a) is an example in which an electron beam or the like is irradiated onto the flat surface side composed of the electrode materials 25 a and 25 b and the resistor material 21 . Fig. 9C (b) is an example of irradiating the inner side of the recess of the electrode materials 25a and 25b and the resistor material 21 with electron beams or the like. The surfaces of the electrode materials 25a and 25b that protrude from the resistor material 21 are not irradiated with electron beams or the like to reduce the influence.

[0142] The resistance value can also be adjusted by using the difference in thickness between the resistor material 21 and the electrode materials 25a and 25b. Fig.9F In the embodiment of FIG. 1 , a step (Δh2) described later can be formed. Various adjustments related to the resistance value and shape can also be made according to the bonding position.

[0143] Then, if Fig.9D As shown in (a), from Fig. 9B The flat plate is removed into a comb-shaped shape by punching or the like in a manner including a region of the resistor material 21 as shown by reference numeral 17. Next, a portion of the first electrode material 25a and the second electrode material 25b is bent by punching or the like, thereby forming a Fig.9D The cross-sectional shape of the structure is shown in the cross-sectional view of (b). In addition, reference numerals 21a and b are welded portions, which are portions connected by electron beam irradiation or the like.

[0144] Then, if Fig.9E As shown, the other end side (35b) of the electrode that is not cut is cut from the remaining area (base) 25b' along L31. The resistor of the docking structure for the current detection device of the first embodiment can be formed. If the manufacturing method of this embodiment is used, it has the advantage that the resistor including the electrodes 35a, 35b and the resistor body 31 can be mass-produced.

[0145] In addition, if Fig.9F As shown in the cross-sectional view of FIG. 4 , welding marks 43a and 43b are formed on the resistor. Generally, the surface of the welding marks produced by electron beams or the like becomes rough. In order to perform precise current detection, it is preferable to fix the bonding wire as close to the resistor as possible, but the welding marks sometimes become an obstacle. According to this embodiment, by Fig. 9C The method described in detail in the description of can avoid the formation of welding marks in the regions 35a-2 and 35b-2 that become the bonding surfaces. Therefore, there is an advantage that the bonding wire can be fixed at a position close to the resistor.

[0146] The resistivity of the shunt resistor of the present embodiment is within a range of 15 to 25 μΩ·cm.

[0147] In addition, the TCR of this resistance alloy is 100×10 -6 / K(25-100℃)below.

[0148] The resistance alloy has a thermoelectric potential with respect to copper within ±1 μV / K. The resistance alloy can also have a thermoelectric potential with respect to copper within ±0.5 μV / K, and can also have a thermoelectric potential with respect to copper within ±0.2 μV / K.

[0149] By having the above characteristics, a resistance alloy suitable for a small and low-resistance shunt resistor can be formed, and a low TCR value can also be achieved. The current detection accuracy of a current detection device using a shunt resistor becomes good, and by miniaturizing the shunt resistor, the space of the current detection device can be saved.

[0150] In the above-mentioned embodiment, the configurations and the like shown in the drawings are not limited to these, and can be appropriately changed within the scope of exerting the effects of the present invention. In addition, the present invention can be implemented with appropriate changes as long as it does not depart from the scope of the purpose of the present invention.

[0151] In addition, the constituent elements of the present invention can be arbitrarily selected and eliminated, and inventions having such selected and eliminated structures are also included in the present invention.

[0152] Industrial Applicability

[0153] The present invention can be used as an alloy for resistors.

[0154] Description of Reference Numerals

[0155] Evaluation samples of alloys for X resistors

[0156] R Applicable area

[0157] 1. Electrode parts at both ends of 3 (the part where current flows)

[0158] 5 Resistor

[0159] 7, 9 Voltage detection unit

[0160] A Shunt resistor

[0161] 11 Monolithic resistor

[0162] 15a, 15b electrodes

[0163] 21Resistance materials in the form of long strips or flat plates

[0164] 25a Long flat plate-shaped first electrode material

[0165] 25b Long flat plate-shaped second electrode material

[0166] 35b The other end of the electrode that is not cut

[0167] 43a, 43b welding marks

[0168] All publications, patents, and patent applications cited in this specification are incorporated herein by reference as is.

Claims

1. A resistance alloy, characterized in that: The resistance alloy is a resistance alloy used for a shunt resistor for current detection. The resistance alloy is a quaternary alloy of copper, manganese, silicon and iron, and does not contain nickel and tin. Manganese is 4.5-5.5% by mass, silicon is 0.05-0.30% by mass, iron is 0.10-0.30% by mass, and the remainder is copper. The resistivity is 15-25 μΩ·cm. Thermoelectric potential of copper is within ±1μV / K. Silicon oxide is formed on the surface.

2. The resistance alloy according to claim 1, characterized in that: TCR is 100×10 -6 / K or less.

3. Use of the resistance alloy according to claim 1 or 2 in a resistor element of a shunt resistor used in a current detection device.

4. A shunt resistor for current detection, characterized in that: The current detection shunt resistor includes a resistor and an electrode. The resistor does not contain nickel and tin, and is a quaternary alloy of copper, manganese, silicon and iron, and is formed by a resistor alloy. The manganese in the resistor alloy is 4.5-5.5% by mass, the silicon is 0.05-0.30% by mass, the iron is 0.10-0.30% by mass, and the rest is copper. The resistivity is 15-25μΩ·cm, and the thermoelectromotive force to copper is within ±1μV / K. Silicon oxide is formed on the surface of the resistor.

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