Side circuit resistor and manufacturing method for it

Abstract

Shunt resistor (10a; 10c) which has the following features: a resistance body (11); a pair of main electrodes (12, 12) which are separate from the resistance body (11); and a pair of voltage detection electrodes (13, 13) that are separate from the respective main electrode (12, 12); wherein each voltage detection electrode (13, 13) is located between the resistance body (11) and the respective main electrode (12, 12) and is connected to them; and wherein each main electrode (12, 12) has at its end a flat part (12f; 12g) and a column-shaped part which is connected to the flat part (12f; 12g), wherein the flat part (12f; 12g) is thinner than the column-shaped part.

Description

Technical area

[0001] The invention relates to a resistor, and more particularly to a shunt resistor made of a metal material using resistance alloy material for the resistor body. Technical background

[0002] The shunt resistor is used to monitor the electrical charging and discharging of a battery current and to prevent battery troubles in advance. The shunt resistor has excellent current detection accuracy, low current drift, and does not generate excessive heat even when a large current is applied. The shunt resistor is used in areas where a particularly low resistance value, such as 1 mΩ or less, is required, and various shunt resistor structures have been proposed (see, for example, JP 2009-216620 A).

[0003] The shunt resistor has cylindrical current terminals (electrodes) on both sides of the resistor body, and the terminals are directly connected with wires. The shunt resistor is also used by welding voltage detection terminals to the connection space or to a connection area containing the current terminals. However, the resistor structure is not necessarily sufficiently low in resistance to ensure excellent current detection accuracy and reduce temperature drift.

[0004] JP 2002 - 372 551 A discloses a mounting structure of a current detection resistor for improving a current detection accuracy of a high current containing a high frequency component, such as a current detection circuit of a switching power supply.

[0005] JP 2008-47571 A discloses a shunt resistor and a current measuring device using the same. The shunt resistor has a resistance between a first terminal and a second terminal and is formed in the shape of a washer. In the current measuring device, a battery has a bolt as a cable terminal support for supporting a cable terminal. The shunt resistor is arranged between the bolt and the cable terminal, and a sleeve-shaped insulator is provided between the bolt and the cable terminal. Summary of the inventionTechnical problem

[0006] The invention was conceived based on the aforementioned circumstances. Therefore, the objects of the invention are to provide a shunt resistor and a manufacturing method thereof, which shunt resistor has excellent current detection accuracy, is capable of reducing temperature variation, can make structures small and compact, and improves operability in use. Solution to the problem

[0007] The object of the present invention is achieved by a shunt resistor according to claim 1 and by a method according to claim 8. The subclaims relate to preferred embodiments of the invention. The shunt resistor of the invention comprises, among other things, a resistance body; further, a pair of main electrodes separated from the resistance body, wherein the voltage detection electrode is provided between the resistance body and the main electrode and is connected thereto. Furthermore, the shunt resistor of the invention comprises a rod-shaped resistance body and a pair of rod-shaped electrodes separated from the resistance body, wherein the end faces of the resistance body and the main electrode are separated.

[0008] Also, a method for manufacturing a shunt resistor of the invention includes, among other things: preparing a resistor body, a pair of main electrodes separated from the resistor body, and a pair of voltage detection electrodes separated from the main electrode; and arranging the end faces of the voltage detection electrodes at both end faces of the resistor body in the length direction, and applying and fixing the main electrode so that the end faces of the voltage detection electrode and the main electrode are opposite to each other.

[0009] According to the invention, each component can be easily manufactured, and high dimensional accuracy can be achieved for each component. Furthermore, in terms of electrical characteristics, an excellent shunt resistor is created because a continuous current path is achieved. By employing a voltage detection electrode, which has a detection terminal for detecting a voltage between the resistor body and the main electrode, as a connecting part, the voltage detection accuracy is further improved because the positional accuracy where the voltage detection terminal is formed is increased.In the resistor having a particularly low resistance value of approximately 0.1 mΩ, current detection becomes possible at a particularly accurate resistance value and a low temperature resistance coefficient exhibited by the resistor body without any influence of the resistance element and the main electrode material. Short description of the drawings Fig. Figure 1 is a perspective view of a shunt resistor useful for understanding the invention. Fig. Figure 2 is an exploded perspective view of the resistor. Fig. 3 is a perspective view of the shunt resistor according to a first embodiment of the invention. Fig. 4A-4G are views showing the manufacturing process and assembly for the first embodiment; and Fig. Figure 4A is an exploded perspective view of the resistor. Fig. Figure 4B is a perspective view at a stage where each component of the resistor has been connected. Fig. Figure 4C is a view in a stage where holes have been formed on the end faces. Fig. 4C is a perspective view in the upper part and a perspective cross-sectional view in the lower part, showing a center line. Fig. Figure 4D is a perspective view at a stage where flat parts have been formed on the main electrodes. Fig. 4E is a perspective view at a stage where voltage detection terminals have been attached. Fig. Figure 4F is a perspective view showing an example of resistor trimming. Fig. 4G is a perspective view showing an example of resistor mounting. Fig. 5 is a perspective view of a shunt resistor according to a second embodiment. Fig. 6A is an exploded perspective view according to the second embodiment. Fig. 6B is a perspective view in a finished state of the second embodiment. Fig. 7 is a perspective view of another shunt resistor useful for understanding the invention. Fig. 8 is an exploded perspective view of the shunt resistor according to Fig. 7 . Fig. 9 is a perspective view of another shunt resistor useful for understanding the invention. Fig. 10 is an exploded perspective view showing the application situation of the shunt resistor according to Fig. 9 shows. Fig. 11 is a perspective view of a shunt resistor useful for understanding the invention. Fig. 12 is an exploded perspective view showing the application situation of the shunt resistor according to Fig. 11 shows. Fig. 13 is an explanatory view of a voltage detection position in a shunt resistor. Fig. 14A is a graph showing a resistance change ratio of the voltage detection position. Fig. Figure 14B is a graph showing the temperature coefficient of the resistance change ratio at the voltage detection position. Description of the embodiments

[0010] Embodiments of the invention as well as examples useful for understanding the invention are described below with reference to Fig. 1 to Fig. 14B. Identical or corresponding parts or elements are designated and explained with the same reference numerals throughout the views.

[0011] Fig. 1 shows a shunt resistor, and Fig. 2 shows an exploded view thereof. The shunt resistor 10 is provided with a columnar resistor body 11 made of a resistance alloy material such as manganin, a pair of columnar main electrodes 12, 12 made of a highly conductive material such as copper, which are separated from the resistor body, and a pair of disc-shaped voltage detection electrodes 13, 13 made of a highly conductive metal material such as copper, which are separated from the main electrode. The voltage detection electrode 13 has a protruding portion protruding from the electrode 13, and a terminal of the voltage detection circuit is connected thereto by welding, etc.

[0012] As shown in the figure, the voltage detection electrode 13 is provided between the resistance body 11 and the main electrode 12 and connected thereto. Furthermore, the end faces of the plate-shaped voltage detection electrode 13 and the end faces of the columnar main electrode 12 are fixed to both end faces of the columnar resistance body 11 in the longitudinal direction so as to face each other. Here, each contact face of the resistance body 11 and the voltage detection electrode 12, and the main electrode 12 and the voltage detection electrode 13, is in contact and connected by pressure bonding, or more precisely, by fusion bonding. Furthermore, the bonded faces are mechanically strong and electrically stable.

[0013] A concrete example of each component will be described. The diameter of the resistor body 11 is approximately 8 mm Ø, and its length is approximately 10 mm. This achieves a resistance characteristic of approximately 0.1 mΩ, and a temperature coefficient of resistance of approximately ±50 ppm / °C. Furthermore, the thickness of the voltage detection electrode 13 is approximately 0.7 mm, and one end face of the detection terminal 13a forms the same face as the end face of the voltage detection electrode 13. Therefore, it becomes possible to directly detect the voltage at the voltage detection terminal 13a based on the resistance value and the temperature coefficient of resistance of the resistor body 11, without any influence from the resistance element of the copper material of the main electrode.

[0014] According to the shunt resistor 10, the mounting process is simplified because the voltage detection electrode and the detection terminal are an integrally connected part. Furthermore, voltage detection of the resistor body 11 at the closest position to it becomes possible because a difference in the fixed position of the detection terminal 13a can be suppressed or prevented. This aspect will be described later.

[0015] Furthermore, since the voltage detection electrode 13 is formed as a single electrode, it never separates from the connected parts. It also has excellent durability, and resistance value changes over time are minimal. Since there is no overlap between the electrode and the resistance body, but rather a columnar shape, and since the electrode and the resistance body are connected across the entire junction on the end face, a smooth current path and heat dissipation are achieved, and the connection strength is also strong.

[0016] According to the shunt resistor of the invention, since the current path between both electrodes is the same, a resistance can be calculated according to the size of the resistor body 11 even if a finite element method simulation is not used, and a resistor with high accuracy can be easily manufactured. That is, it becomes easy to design a small shunt resistor because the size of the resistor body and the copper electrode can be determined taking into account the required resistance value and heat generation. As described above, it also becomes easy to connect the terminal or wiring because it becomes possible to form a flat part or a screw bolt or a screw hole on the electrodes, making it possible to make the resistor easy to use.

[0017] Next, a manufacturing method for the shunt resistor 10 will be explained. First, a resistor body 11, a pair of main electrodes 12, 12 separated by the resistor body, and a pair of voltage detection electrodes 13, 13 separated by the main electrodes are prepared. The resistor body 11 is formed to be columnar by cutting long rod-like material made of manganin, etc., to a prescribed size so that end faces, i.e., cut surfaces, are provided at both ends. The main electrode 12 is similarly formed to be columnar by cutting long rod-like material made of copper to a prescribed size so that end faces, i.e., cut surfaces, are provided at both ends.The voltage detection electrode 13 has a plate-shaped portion and a detection terminal 13a protruding from the plate-shaped portion. The electrode 13 is formed into a prescribed shape by punching a flat copper sheet, etc. Pressing or etching processing can be used to process the sheet-shaped copper plate.

[0018] Although an exemplary material for the voltage detection electrode 13 is copper, a metal film such as nickel may be formed on the surface of the voltage detection electrode 13. By forming a nickel film thereon, diffusion bonding becomes easy, bonding in a nitrogen atmosphere becomes possible, and productivity improves. Forming a metal film on the surface of the voltage detection electrode 13 can be carried out by using a sheet-shaped copper plate on which a metal film has been previously deposited, or by forming a metal film after processing into the shape of the voltage detection electrode 13. Methods for forming the metal film include electrolysis and plating without electrolysis.

[0019] Next, the joint surface is ground. The joint surface consists of both end faces of the resistor body 11, one end face of the main electrode, and the end faces of the voltage detection electrodes connected to the resistor body 11 and the main electrode 12. Regarding the voltage detection electrode 13, it is desirable to grind the joint surface before forming the metal film, especially when the surface is covered with a metal film. The joint becomes stronger by using abrasive material and a grinding process, so that the joint surface can achieve a state close to a mirror surface.Furthermore, it is possible to provide the plate portion of the voltage detection electrode 13 at each end face of the resistor body at both ends in the length direction, and to fix it between the resistor body 11 and the main electrode 12 so that the end face of the resistor body 11 and the end face of the main electrode are opposite each other. That is, the end faces are adjacent to each other, opposite face to face, and they are fixed by diffusion bonding, etc.

[0020] To explain diffusion bonding (thermo-pressure bonding), the main electrode 12, the voltage detection electrode 13, the resistance body 11, the voltage detection electrode 13, and the main electrode 12 are arranged in this order, and heated to 500-900°C by applying a prescribed pressure in the axial direction. A strong and homogeneous bond can be achieved across almost the entire bond surface of the contacting metal material because the atoms of each metal material diffuse mutually in the bond interface. Resistance welding is another joining method.In the case of using a resistance welding process, the main electrode 12, the voltage detection electrode 13, the resistance body 11, the voltage detection electrode 13 and the main electrode 12 are arranged in this order, and by applying a prescribed pressure and a prescribed current in the axial direction, they are joined together mainly by contact resistance heat generation between the joining materials.

[0021] It is desirable that bonding of the resistance body, the voltage detection electrodes, and the main electrodes be performed using a method that can unite the entire joining surfaces, such as pressure bonding. Additionally, electron beam welding may be used, in which case an electron beam is irradiated onto the parts to be joined of each metal material. Similarly, it is also possible to use laser welding, such as a YAG laser. However, when using a YAG laser, there is a possibility that a difference in current distribution will be generated because it may not be possible to achieve a sufficiently good connection at the center of the joint face, although partial connection at the periphery can be achieved by welding.

[0022] The shunt resistor 10, which is in Fig. 1 is completed by the method explained above. Regarding the resistance value, the size of the resistance body 11 is largely determined. Since improved dimensional accuracy can be achieved using the columnar resistance material, it is possible to control the resistance value with high precision. Furthermore, if the resistance body is trimmed or fine-tuned by cutting or grinding a surface of the resistance body 11, it becomes more accurate.

[0023] According to the above-mentioned process or manufacturing method, a shunt resistor with high accuracy with good handleability, with good operability in use can be produced by a simple manufacturing process because the voltage detection electrode and the terminal of the shunt resistor can be formed simultaneously.

[0024] An example of connecting a plate-shaped voltage detection electrode and a columnar main electrode to the columnar resistance body is explained in this example; however, their diameters are not necessarily the same. Furthermore, it is also possible for some or all of the materials to have a square or angular columnar shape.

[0025] Fig. 3 shows the shunt resistor of a first embodiment of the invention. The shunt resistor 10a has a structure in which flat parts 12f, 12f are formed at both ends of the columnar electrodes 12, 12. The flat part 12f has an opening 14 therein. Furthermore, it forms a structure to which a bus bar connected to a battery, etc., can be connected and fixed to the flat part using a bolt and a nut through the opening 14. The opening 14 can be a screw hole and can fix the bus bar to the flat part 12 by screwing. Since the flat part 12f is shaped, it becomes easy to connect and fix the bus bar or tab-shaped metal terminal parts.

[0026] Fig. 4A-4F show an example of a manufacturing method according to the first embodiment. As in Fig. 4A and Fig. 4B shows a resistor body 11 made of a resistor alloy material such as manganin, etc., and a pair of main electrodes 12, 12 made of highly electrically conductive material such as copper, separated from the resistor body. The resistor body 11 and the main electrode 12 are columnar materials of almost the same diameter. The main electrodes 12, 12 are connected to and abut both ends of the resistor body 11 in the length direction, so that the end face of the resistor body 11 and the end face of the main electrode 12 face each other.

[0027] For the connection of the resistor body 11 and the main electrode 12, pressure joining, or more specifically, friction pressure joining (friction welding), can be used. Friction pressure joining is a technology in which the materials to be joined are rubbed against each other at high speed, which achieves the heat generated by friction, and simultaneously bonds them by applying pressure. As a result, strength can be ensured, the bonding state of the materials is excellent, and the resistance properties can be stabilized. Specifically, the resistor body is first fixed with a jig, and the main electrode material is fixed with another rotating jig.While the main electrode material is rotated at approximately 3000-6000 rpm, being pressed against the end face of the resistor body under a pressure of approximately 1kN-10kN, and this is continued for 0.1 seconds to 10 seconds, the end face of the resistor body and the end face of the main electrode are bonded. Similarly, the other main electrode is bonded to the other end face of the resistor body. Furthermore, any burr created at the bonding part is removed. Regarding the bonding method, methods such as wax bonding or coating can be used.

[0028] As in Fig. Next, as shown in Figure 4C, the hole 12h is formed at the end faces of the main electrodes 12, 12. The depth of the hole is set proportional to the cross-section or area of ​​the flat part to be formed. Although the hole does not necessarily have to be formed, forming the hole makes it easy to form the flat part with a press. Next, the flat part 12f is formed by compressing the part where the hole 12h was formed with the press. The opening 14 is formed in the flat part 12f. As shown in Fig. As shown in Figure 4D, the lower end face of the shunt resistor becomes almost flat by shaping the position of the flat part at the bottom of the resistor, and this is convenient for installation. Therefore, a structure having a flat part 12f, 12f at both ends of the electrodes 12, 12, and an opening 14 in the flat part 12f is achieved. Furthermore, the flat part 12f and the opening 14 can be formed by cutting. Furthermore, as further applications of the hole 12h, by inserting a lead wire, which is a current path, into the hole 12h and compressing the hole 12h (Kashime), it is also possible to fix the lead wire and the main electrode 12 when connecting them.

[0029] As in Fig. Next, as shown in Figure 4E, the detection terminal 13a is welded to the main electrode 11. A hollow portion may be previously formed for positioning the detection terminal 13a to be attached to the main electrode 11. A portion of the surface of the resistance body is cut down using a rotating blade 15, as shown in Fig. 4F and the resistance value is adjusted if necessary. Fig. 4G is a perspective view showing an example of attaching a shunt resistor of the embodiment to the bus bar 19. A bolt 21 is inserted through the hole 14 formed in the flat part 12f and into a hole formed in the bus bar 19, and is tightened and fixed with a nut not shown in the figure.

[0030] Fig. 5 is a shunt resistor of a second embodiment of the invention. In this example, the position of the flat portion 12g having the opening 14 is formed approximately at the midpoint of the resistor's height. That is, the flat portion is formed at a position passing through the midpoint of the resistor's cross-section. Fig. 6A and Fig. 6B shows an example of the manufacturing process. Just as in the above-mentioned embodiment, a material that will become the resistance body, a material that will become the voltage detection electrode, and a material that will become the main electrode are first prepared, and a wax or coating material is additionally prepared. The voltage detection electrode has a detection terminal 13a. The flat part 12g is previously formed at a part of the main electrode 12. The opening 14 of the flat part 12g can be previously formed or can be formed after connection with any material.

[0031] In the second embodiment, the connection of the resistance body 11, the voltage detection electrode 13, and the main electrode 12 is performed by brazing and soldering. Brazing and soldering are a method of providing a coating or wax material 16, such as copper, silver, gold, platinum, and nickel, etc., to perform the connection by applying heat. Specifically, first, as shown in Fig. As shown in Figure 6a, the voltage detection electrode 13 and the main electrode 12 are fixed by providing the wax or coating material 16 at each connecting part of the resistance body 11 and by pressing these parts from both sides with the jig. Next, the parts are heated to approximately 500°C-900°C in a batch or treatment furnace. At this time, the furnace is placed in an atmosphere that can prevent the metal from oxidizing by filling it with inert gas, such as argon, nitrogen, hydrogen, or by placing it under vacuum. According to this method, as described in Fig. As shown in Figure 6B, a shunt resistor can be formed by connecting each metal material. In soft soldering and brazing, the method has the advantage that compression is not required, unlike press-connecting, and this connection is also simple when installing the detection terminal protruding from the voltage detection electrode.

[0032] In addition, the flat part 12g can be formed by pressing or cutting, as in the aforementioned flat part 12f, after the voltage detection electrode 13 and the main electrode 12 are connected to both end faces of the resistance body 11. In this embodiment, just as in Fig. 4G the resistor can be attached to a bus bar etc.

[0033] Fig. 7 and Fig. 8 shows another shunt resistor. In the example, the end faces of the main electrodes 12, 12 of the columnar shape (rod) are directly connected to both ends of the resistance body 11 of the columnar shape (rod), without providing the voltage detection electrode. Regarding the connection, a pressure bonding method such as friction pressure bonding or a diffusion bonding method, or brazing or soldering can be used. In the case of brazing and soldering, a wax or coating material is provided between the resistance body 11 and the main electrode 12, and they are connected. After that, the detection terminal 13a is welded to the main electrode 12. The detection terminal 13a is welded at a position as close as possible to the connection interface with the resistance body 11.

[0034] The shunt resistor has a characteristic in that the resistor is columnar. That is, the resistor body 11 and the main electrode 12 are columnar in design. The columnar material offers excellent material yield, is inexpensive, and easy to process, and high dimensional accuracy can be achieved.

[0035] Furthermore, the shunt resistor has a structural feature in that the end faces of the resistor body 11 and the main electrode 12 are in mutual contact. By using a diffusion bonding method, a friction pressure bonding method, or brazing or soldering as the bonding method and forming a bonding structure of mutually abutting end faces, a homogeneous bonding surface can be formed in all aspects of the end face. Material costs are then kept to a minimum. Since current flows linearly, there are many advantages in electrical characteristics. Furthermore, a small, compact, and simple structure is achieved.

[0036] Fig. Figure 9 shows another shunt resistor. In the example, the resistor has, in addition to the structure shown in Fig. 7 and Fig. 8 a threaded bolt part 12n (bolt state electrode part) where a screw thread is formed on the outer surface of the main electrode 12. Fig. Figure 10 shows the application situation. By inserting the screw bolt portion 12n into each hole of a disc 18 of a bus bar 19 connected to a cable and a disc 18, and tightening the nut 20, the bus bar 19 can be fixed to the main electrode 12, as shown on the right side of the figure. By attaching the detection terminal 13a to the voltage detection electrode 13, a voltage generated at both ends of the resistance body 11 can be further detected.

[0037] Fig. Figure 11 shows another shunt resistor. In this example, the resistor has a hole in an end face 12a of the main electrode 12, and a screw hole portion 12x in which a screw thread is formed on an inner surface of the hole. Fig. 12 shows the situation during use. By inserting the screw 21 into engagement with the screw hole portion 12x through an opening (not shown) of the bus bar 19, which is a current flow path, and tightening the screw 21, the bus bar 19 can be fixed to the end face 12a of the main electrode 12. By attaching the detection terminal 13a to the voltage detection electrode 13, the voltage generated at both ends of the resistance body 12 can be further detected.

[0038] Next, the influence of a voltage detection position is explained when a copper electrode is connected to both end faces of the resistor body. Fig. Figure 13 shows a model where both end faces of a columnar square resistor body of approximately 0.1 m Ω are connected to square columnar copper electrodes of the same cross-sectional size. Fig. Figure 14a shows a simulation result of the resistance change ratio ΔR according to the voltage detection position (distance X from inside the electrode). Fig. 14B shows a simulation result of a temperature coefficient of resistance corresponding to the voltage detection position (distance X from the inside of the electrode) when the temperature coefficient of resistance of the resistor body is assumed to be zero.

[0039] As is clear from these results, in the case of a resistor of approximately 0.1 mΩ, the influence of the resistance element and the high temperature coefficient of resistance of the copper material electrode increases with the increase in the distance X from the inside of the electrode. Furthermore, the detection voltage at the voltage detection position X becomes higher than the voltage between the two end faces of the resistor itself, and the temperature coefficient of resistance becomes higher than the temperature coefficient of resistance of the resistor itself.

[0040] That is, it is clear that the difference in the voltage detection position greatly influences the high accuracy of voltage detection. According to the shunt resistor of the invention, which has the voltage detection electrode, the difference in the resistance value change ratio and the temperature coefficient of the resistor are extremely small because the voltage detection position X, which is the distance from the inside of the electrode, is fixed at approximately zero.

[0041] In each embodiment above, any method, such as pressure bonding (diffusion bonding and friction pressure bonding), brazing and soldering, laser welding, and electron beam welding mentioned above, can be used to join each material of the resistance body, the main electrode, and the voltage detection electrode. The joining conditions or parameters should be appropriately varied depending on the size and material to be joined. Industrial applicability

[0042] The invention can be suitably used for a current sensing resistor made of metal material using resistance alloy material as a resistance body, particularly for a resistor having a very small resistance range of 1mΩ or less.

Claims

[1] Shunt resistor (10a; 10c) having: a resistance body (11); a pair of main electrodes (12, 12) separated from the resistance body (11); and a pair of voltage detection electrodes (13, 13) separated from the respective main electrode (12, 12); wherein each voltage detection electrode (13, 13) is provided between the resistance body (11) and the respective main electrode (12, 12) and is connected thereto; and wherein each main electrode (12, 12) has at its end a flat part (12f; 12g) and a columnar part connected to the flat part (12f; 12g), the flat part (12f; 12g) being thinner than the columnar part. [2] A shunt resistor (10a; 10c) according to claim 1, wherein each connected end face is abutted and connected by means of pressure bonding or brazing and soldering. [3] A shunt resistor (10a; 10c) according to claim 1, wherein the voltage detection electrodes (13, 13) each have a projecting part. [4] A shunt resistor (10a; 10c) according to claim 1, wherein the respective voltage detection electrode (13, 13) and the respective main electrode (12, 12) are fixed to both end faces of the resistor body (11) in the longitudinal direction so as to be opposite to each other. [5] Shunt resistor (10a; 10c) according to claim 1, wherein the resistance body (11) is columnar. [6] A shunt resistor (10a; 10c) according to claim 1, wherein the flat part (12f; 12g) has an opening (14). [7] A method for producing a shunt resistor (10a; 10c) comprising: Preparing a resistance body (11), a pair of main electrodes (12, 12) separated from the resistance body (11), and a pair of voltage detection electrodes (13, 13) separated from the respective main electrode (12, 12); Providing the voltage detection electrodes (13, 13) at both end faces of the resistance body (11) in the length direction thereof; Applying the main electrodes (12, 12) such that an end face of the respective voltage detection electrode (13, 13) and an end face of the respective main electrode (12, 12) are opposite each other and fixing these parts; wherein each main electrode (12, 12) has at its end a flat part (12f; 12g) and a columnar part connected to the flat part (12f; 12g), the flat part (12f; 12g) being thinner than the columnar part. [8] Method according to claim 7, wherein the resistance body (11) is columnar. [9] A method according to claim 7, wherein the resistance body (11), the main electrodes (12, 12) and the voltage detection electrodes (13, 13) are fixed to each other by press-fitting or brazing or soldering.

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