Resistor manufacturing method

Abstract

Even when placed in a high temperature environment for a long time, the rate of change in volume resistance is suppressed. Most Resistor manufacturing method ,oh and a resistor. [Solution] A copper alloy material containing 10.0 to 14.0 mass% Mn, 1.0 to 4.0 mass% Ni, 0 to 0.10 mass% Al, 0 to 0.10 mass% Mg, with the remainder being Cu and unavoidable impurities, is prepared. The copper alloy material is melted and cast to produce an ingot. The ingot is hot-rolled to produce a hot-formed body. The hot-formed body is cold-rolled to produce a cold-formed body. The cold-formed body is held at a predetermined temperature range to remove residual strain that has occurred in the cold-formed body due to cold rolling. The cold-formed body from which residual strain has been removed is held at a temperature range of 110°C or higher and lower than 200°C to produce a copper alloy sheet.

Description

[Technical Field]

[0001] The disclosure provided herein relates to a method for manufacturing a resistor. By law Regarding. [Background technology]

[0002] Patent Document 1 discloses a copper alloy sheet material used in a resistor. In Patent Document 1, the amount of Mn and other elements contained in the copper alloy sheet material is adjusted to reduce the resistance temperature coefficient of the copper alloy sheet material, so that the resistance of the resistor remains stable even when the ambient temperature changes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6762438 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the method for producing a copper alloy sheet material disclosed in Patent Document 1, the arrangement of different elements contained in the copper alloy sheet material may not be regularized but may remain disordered, and therefore, if the copper alloy sheet material is left in a high-temperature environment for a long period of time, the rate of change in volume resistivity of the copper alloy sheet material may change significantly.

[0005] The object of the present disclosure is to provide a method for manufacturing a resistor in which the rate of change in volume resistance is suppressed even when the resistor is placed in a high-temperature environment for a long period of time. The law The purpose is to provide. [Means for solving the problem]

[0008] The method for manufacturing a resistor according to the disclosed embodiment includes: a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot, hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; By maintaining the cold-formed body within a predetermined temperature range, residual strain generated in the cold-formed body by cold rolling is removed, The cold-formed body with residual strain removed is then heated at a temperature between 110°C and 200°C. 1.0~5.4 hours and holding the copper alloy plate material (300) to manufacture the copper alloy plate material (300). A resistor (110) is manufactured by welding a copper alloy plate material to a metal bus bar (200); By maintaining the resistor at 200°C or higher, distortion caused in the copper alloy plate material by welding is removed.

[0014] This prevents the rate of change in the volume resistivity of the copper alloy sheet from increasing even when the sheet is left in a high-temperature environment for a long period of time.

[0015] The reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments below, and do not in any way limit the technical scope. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a block diagram illustrating a control module. [Figure 2] FIG. 2 is a schematic diagram showing a current sensor. [Figure 3] 1 is a flowchart illustrating a method for manufacturing a resistor. [Figure 4] 1 is a flowchart illustrating a method for manufacturing a resistor. [Figure 5] 1 is a flowchart illustrating a method for manufacturing a resistor. [Figure 6] 1 is a diagram showing the composition materials of the test specimens. [Figure 7] FIG. 2 is a schematic diagram illustrating a device and a method for measuring the volume resistivity of a test piece. [Figure 8] 1 is a table showing the volume resistivity of test pieces and the rate of change thereof. [Figure 9] 1 is a graph showing the temperature during SRO annealing. [Figure 10] 1 is a diagram showing the relationship between SRO annealing time and the rate of resistance change, and the relationship between SRO annealing temperature and the progress of SRO annealing. [Figure 11] 1 is a graph showing the progress of SRO annealing. [Figure 12] 12 is a graph showing an enlarged view of the area surrounded by the dashed line in FIG. 11. [Figure 13] 1 is a table showing the resistance value and the rate of change in resistance of a test piece during a durability test. [Figure 14] 10 is a graph showing the rate of change in resistance during a durability test. [Figure 15] 10 is a graph showing the relationship between the rate of resistance change due to a durability test and the rate of resistance change due to SRO annealing. [Figure 16] 10 is a graph showing the resistance change rate of a resistor subjected to SRO annealing. [Figure 17] 10 is a graph showing the resistance change rate of a resistor subjected to SRO annealing. [Figure 18] 10 is a graph showing the resistance change rate of resistors that have undergone strain relief annealing. [Figure 19] 10 is a graph showing the resistance change rate of a resistor that has undergone strain relief annealing. [Figure 20] 10 is a graph showing the resistance change rate of resistors that have undergone stress relief annealing and SRO annealing after welding. [Figure 21] 10 is a graph showing the resistance change rate of a resistor that has been subjected to strain relief annealing and SRO annealing after welding. [Figure 22] 10 is a graph showing the resistance change rate of a resistor that has undergone SRO annealing before welding and stress relief annealing after welding. [Figure 23] 10 is a graph showing the resistance change rate of a resistor that has undergone SRO annealing before welding and stress relief annealing after welding. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. Portions corresponding to matters described in the previous embodiments may be assigned the same reference numerals in the subsequent embodiments, and duplicated descriptions may be omitted. When only a portion of the configuration is described in each embodiment, the description of the previous embodiment may be applied to the remaining portions of the configuration.

[0018] In each embodiment, it is possible to combine parts that are specifically expressly permitted to be combined with each other. Furthermore, even if it is not explicitly stated that a combination is possible, it is also possible to partially combine multiple embodiments, an embodiment and a variation, or multiple variation embodiments, as long as there is no particular problem with the combination.

[0019] First Embodiment <Control module> As shown in FIG. 1, the control module 10 includes a sensor device 20 and a control device 30 .

[0020] The sensor device 20 detects a physical quantity. The sensor device 20 converts the physical quantity into an analog signal. In the drawings, the sensor device 20 is indicated as SD. SD is an abbreviation for Sensor Device.

[0021] Examples of items that are detected by the sensor device 20 include a battery, a converter, an inverter, a motor, an engine, a drive train, and a bus bar. Examples of physical quantities that are detected by the sensor device 20 include current, voltage, temperature, acceleration, angular velocity, flow rate, and pressure. The items and physical quantities that are detected by the sensor device 20 are not particularly limited, even if not explicitly stated.

[0022] The control device 30 receives the physical quantity converted into an analog signal by the sensor device 20. The control device 30 converts the analog signal into a digital signal. In the drawings, the control device 30 is indicated as CU, which stands for Control Unit.

[0023] The control module 10 having the sensor device 20 and the control device 30 can be appropriately adopted in the vehicle systems of mobile objects such as electric vehicles, hybrid vehicles, gasoline vehicles, trucks, etc. The mobile objects to which the control module 10 is applied are not particularly limited, even if not explicitly stated.

[0024] As described above, current is one of the physical quantities detected by the sensor device 20. The current sensor 100 included in the sensor device 20 will be described in detail below.

[0025] <Current sensor> The current sensor 100 shown in Fig. 2 has a function of detecting a current flowing through a PN bus bar that connects a battery pack mounted on a mobile object to a PCU. PCU stands for Power Control Unit. The PCU includes at least an inverter. The PCU may also include a converter. The PN bus bar includes a P bus bar connected to the positive terminal of the battery pack and an N bus bar connected to the negative terminal of the battery pack.

[0026] The current sensor 100 includes a resistor 110, a wiring board 120, and a connector .

[0027] The resistor 110 has a metal bus bar 200 and a shunt resistor 300. The metal bus bar 200 and the shunt resistor 300 are welded together. The metal bus bar 200 and the shunt resistor 300 are made of different types of metal materials.

[0028] The metal bus bar 200 has a first metal bus bar 210 and a second metal bus bar 220. The first metal bus bar 210 and the second metal bus bar 220 are connected via a shunt resistor 300.

[0029] A first hole 210a is formed in the first metal bus bar 210. A second hole 220a is formed in the second metal bus bar 220. A bolt is passed through the first hole 210a to connect the metal bus bar 200 and the PN bus bar. A bolt is also passed through the second hole 220a to connect the metal bus bar 200 and the PN bus bar.

[0030] A detection pin 230 is connected to the metal bus bar 200. The detection pin 230 has a first detection pin 231 and a second detection pin 232. The first detection pin 231 is connected to the first metal bus bar 210. The second detection pin 232 is connected to the second metal bus bar 220. The first detection pin 231 and the second detection pin 232 are arranged side by side with the shunt resistor 300 sandwiched between them in the direction in which the first hole 210a and the second hole 220a are arranged.

[0031] A detection pin 230 is connected to the wiring board 120. A connector 130 is also connected to the wiring board 120. The connector 130 is connected to the control device 30 via a wire harness. In this way, the current sensor 100 is electrically connected to the control device 30.

[0032] With the above-described configuration, the voltage across the shunt resistor 300 is input to the control device 30. The control device 30 stores the resistance value of the shunt resistor 300. The control device 30 calculates the current flowing through the shunt resistor 300 from the input voltage and the stored resistance value. In this way, the current flowing through the PN bus bar is detected.

[0033] Naturally, when a current flows through the shunt resistor 300, the temperature of the shunt resistor 300 rises. If the shunt resistor 300 is left in a harsh environment such as a high temperature for a long period of time, the durability of the shunt resistor 300 may be impaired, and there is a risk that the actual resistance value of the shunt resistor 300 may deviate from the resistance value stored in the control device 30. As a result, there is a risk that the accuracy of current detection may decrease. The shunt resistor 300 will be described in detail below.

[0034] <Shunt resistor composition materials> The shunt resistor 300 is a copper alloy sheet material. The copper alloy sheet material contains Mn, Ni, Mg, and the balance Cu and unavoidable impurities. The copper alloy sheet material may also contain Al. The reason why the copper alloy sheet material contains these elements is as follows.

[0035] Mn dissolves in Cu and reduces the temperature coefficient of resistance of the shunt resistor 300. However, if the amount of Mn is excessive, the volume resistivity increases. Therefore, the amount of Mn is set to 10.0 to 14.0 mass %. The preferable amount of Mn is 11.0 to 13.0 mass %.

[0036] Ni dissolves in Cu and reduces the temperature coefficient of resistance of the shunt resistor 300. However, if the Ni content is excessive, the volume resistivity increases. Therefore, the Ni content is set to 1.0 to 4.0 mass %. The Ni content is preferably 2.00 to 3.00 mass %.

[0037] Mg improves the workability during hot rolling, which will be described later, and the preferred Mg content is 0.001 to 0.05 mass %.

[0038] If oxygen gets mixed into the shunt resistor 300, Cu2O may precipitate, causing hydrogen embrittlement. Therefore, Al is added to the shunt resistor 300. This forms Al2O3, which traps oxygen and suppresses the precipitation of Cu2O. The preferred Al content is 0.001 to 0.05 mass %.

[0039] The unavoidable impurities are trace elements that are unintentionally mixed into the copper alloy material from the furnace walls of the casting furnace during the melting and casting process described below, and their content is within a range that does not adversely affect the electrical characteristics of the shunt resistor 300. Examples of unavoidable impurities include C, P, S, Mo, Si, Cr, O, and N. The contents of these elements are preferably limited as shown below, with the lower the better. C≦0.03% by mass, preferably C≦0.01% by mass. P≦0.03% by mass, preferably P≦0.01% by mass. S≦0.03% by mass, preferably S≦0.01% by mass. Mo≦0.03% by mass, preferably Mo≦0.01% by mass. Si≦0.05% by mass, preferably Si≦0.03% by mass. Cr≦0.05% by mass, preferably Cr≦0.03% by mass. O≦0.03 mass%, preferably O≦0.01 mass%. N≦0.03 mass%, preferably N≦0.01 mass%. In order to prevent deterioration of the electrical characteristics of the shunt resistor 300, the total content of impurity elements including the above-mentioned C, P, S, Mo, Si, Cr, O, and N is preferably 0.30 mass% or less. It is more preferable that this total content be 0.10 mass% or less.

[0040] <Resistor manufacturing method> The shunt resistor 300 of this embodiment and the resistor 110 including it are manufactured through the process shown in FIG. 3, and therefore fluctuations in volume resistance are suppressed even when placed in a harsh environment.

[0041] First, in step S10, a copper alloy material containing 10.0 to 14.0 mass % of Mn, 1.0 to 4.0 mass % of Ni, 0 to 0.10 mass % of Al, 0 to 0.10 mass % of Mg, and the balance being Cu and unavoidable impurities is prepared.

[0042] In step S20, the copper alloy material is melted and cast to produce an ingot. The melting and casting methods and conditions are not particularly limited.

[0043] If the ingot is left as is, elements are likely to segregate, and there is a risk that uniform properties will not be obtained. Therefore, in step S30, the ingot is subjected to a homogenization heat treatment to remove the element segregation, and a heat-treated body with a homogenized internal structure is obtained.

[0044] In step S40, the heat-treated body is hot-rolled. This produces a hot-formed body. The hot-rolling is performed to homogenize the structure of the heat-treated body and process it into a rough shape. The method and conditions of the hot-rolling are not particularly limited as long as the desired homogenization of the structure and processing into a rough shape are possible.

[0045] In step S50, the hot-formed body is cold-rolled. This produces a cold-formed body. Normally, high thickness accuracy cannot be obtained by hot rolling alone. Cold rolling is performed to process the body to the final thickness dimension. The method and conditions for cold rolling are not particularly limited as long as the desired dimensional accuracy can be obtained. Note that, before cold rolling, the oxidized region on the surface of the hot-formed body may be removed.

[0046] In step S60, the cold-formed body is annealed by holding it at a predetermined temperature range. This recrystallizes the cold-formed body and removes residual strain caused in the cold-formed body by cold rolling. The temperature range for the annealing treatment can be, for example, 500°C to 850°C.

[0047] If the residual strain is not sufficiently removed by annealing, the strain will gradually be relaxed in the environment in which it is used, and the rate of change in the volume resistance value of the shunt resistor 300 will increase.

[0048] If the annealing temperature is too low or the annealing time is too short, the removal of strain and recrystallization will be insufficient. The lower limit of the annealing temperature is 500°C or higher, more preferably 600°C or higher. The lower limit of the annealing time is preferably 30 seconds or longer.

[0049] If the annealing temperature is too high or the annealing time is too long, the crystal grains may grow too rapidly, resulting in a decrease in material strength. The upper limit of the annealing temperature is 850°C or less, more preferably 800°C or less. The upper limit of the annealing time is preferably 3 hours or less.

[0050] In step S70, the cold-formed body from which residual strain has been removed is held at a temperature in the range of 110°C or higher and lower than 200°C to perform SRO annealing. This generates a short-range ordered arrangement in the cold-formed body. SRO stands for Short Range Order.

[0051] In the cooling process of the hot rolling treatment in step S40, short-range ordered arrays may be generated in the hot-formed body. However, the cold rolling in step S50 destroys the short-range ordered arrays. In addition, in the cooling process after the annealing in step S60, short-range ordered arrays may be generated in the cold-formed body. However, if the temperature drop is rapid, the short-range ordered arrays are not sufficiently generated. Therefore, in step S70, the cold-formed body is subjected to a heat treatment aimed at short-range ordered arrays.

[0052] If the SRO annealing temperature is too low or the SRO annealing time is too short, the generation of short-range ordered arrays will be insufficient. If the SRO annealing temperature is too high, the generation of short-range ordered arrays may be insufficient. From the perspective of generating short-range ordered arrays, even if the SRO annealing time is too long, it is unlikely to be a major problem. However, from the perspective of manufacturing costs, if a sufficient amount of short-range ordered arrays is generated, subsequent SRO annealing is unnecessary. Therefore, the SRO annealing time is preferably less than 24 hours. The temperature and time to resolve this issue will be described later.

[0053] By going through the manufacturing process of steps S10 to S70 described above, a copper alloy sheet material is manufactured as the shunt resistor 300. The manufacturing method of the shunt resistor 300 is a process that precedes the welding process of step S80 described next. To indicate this, dashed lines are added in Fig. 3 and Figs. 4 and 5 described below.

[0054] Next, in step S80, the shunt resistor 300 and the metal bus bar 200 are laser-welded.

[0055] Finally, in step S90, the metal bus bar 200 to which the shunt resistor 300 is welded is held within a predetermined temperature range to perform strain relief annealing, which removes strain that has occurred in the shunt resistor 300 and the metal bus bar 200 due to the laser welding. By going through the above steps, the resistor 110 is manufactured.

[0056] The temperature for stress relief annealing and the temperature for SRO annealing may overlap. However, the temperature for stress relief annealing is generally 200°C or higher, which is the temperature at which oxygen-free copper recrystallizes. Annealing temperatures for removing stress from this material are described in, for example, Japanese Patent Publication Nos. 7158053, 7167385, 6961861, and 6762438.

[0057] As will be described later, the temperature of 200°C is not necessarily the most suitable temperature for achieving short-range ordering of the shunt resistor 300. Therefore, when actually manufacturing the shunt resistor 300 and the resistor 110, a clear distinction is made between the temperature range for performing strain relief annealing and the temperature range for performing SRO annealing. These temperature ranges are clearly distinguished. The temperature range for performing strain relief annealing is higher than the temperature range for performing SRO annealing. The temperature range for strain relief annealing can be, for example, 200°C or higher and 400°C or lower. The temperature for performing SRO annealing is lower than 200°C.

[0058] Up to this point, an example has been shown in which SRO annealing is performed immediately after performing step S60. An example has been shown in which SRO annealing is performed to manufacture a copper alloy sheet material as the shunt resistor 300. However, the copper alloy sheet material as the shunt resistor 300 may be manufactured without performing SRO annealing. For example, as shown in FIGS. 4 and 5, SRO annealing may be performed on the shunt resistor 300 welded to the metal bus bar 200 after the welding process of step S80. Alternatively, a copper alloy sheet material as the shunt resistor 300 may be manufactured without performing SRO annealing, and then the shunt resistor 300 may be welded to the metal bus bar 200, and then SRO annealing may be performed.

[0059] In the manufacturing method shown in Fig. 4, SRO annealing is performed in step S70 after the welding process in step S80, and then strain relief annealing is performed in step S90. In this manufacturing method, once the temperature reaches the temperature range for performing SRO annealing from room temperature, the temperature is maintained in that temperature range, or the temperature increase rate is slowed in that temperature range. In this way, SRO annealing may be performed during the temperature increase process from room temperature to the temperature range for performing strain relief annealing. Note that after performing SRO annealing, the temperature may be lowered once and then raised again to perform strain relief annealing.

[0060] In the manufacturing method shown in FIG. 5, strain relief annealing is performed in step S90 after the welding process in step S80, and then SRO annealing is performed in step S70. In this manufacturing method, the temperature is first raised from room temperature to the temperature at which strain relief annealing is performed, and strain relief annealing is performed. Thereafter, while the temperature is being lowered to room temperature, if the temperature reaches the temperature range at which SRO annealing is performed, the temperature is maintained in that temperature range, or the temperature lowering rate is slowed within that temperature range. In this way, SRO annealing may be performed during the temperature lowering process from the temperature range at which strain relief annealing is performed to room temperature. Note that after strain relief annealing is performed, the temperature may be lowered once, and then raised again to perform SRO annealing.

[0061] <Production of test specimens> A vacuum induction furnace was used to produce an ingot of copper alloy material having the composition shown in Figure 6. The composition of these materials is expressed in mass percent. The ingot was subjected to homogenization heat treatment and then hot-rolled to form a 5 mm thick hot-formed plate. The oxidized regions on the surface of the hot-formed plate were then removed by surface grinding, and the resulting plate was cold-rolled to form a 2.8 mm thick cold-formed plate. Several test pieces measuring 2.8 mm thick, 2 mm wide, and 130 mm long were taken from the resulting cold-formed plate. Several test pieces were annealed. SRO annealing was also performed on some of these test pieces. SRO annealing was performed at 110°C, 130°C, 150°C, 170°C, 190°C, and 210°C for 12 hours.

[0062] <Volume Resistivity Measurement> Next, as shown in FIG. 7 , the test piece was placed in a thermostatic chamber 400. Both ends of the test piece were held by first alligator clips 410 and connected to a constant current source 421 of a resistance meter 420. Two platinum wires 430 were connected to the center of the test piece, spaced 40 mm apart, and second alligator clips 440 were connected to them. The distance between the two platinum wires 430 was long enough to ensure a stable current distribution. The two second alligator clips 440 were then connected to a voltmeter 422 of the resistance meter 420. A current was passed between the two first alligator clips 410, and the voltage was measured by the two second alligator clips 440. In this way, the volume resistance of the test piece was measured. Of course, the volume resistivity of the test piece may be calculated from this measured volume resistance value.

[0063] The resistance meter 420 used was the R3543 manufactured by Hioki E.E. Corporation. The measurement method was the four-terminal method as described above. The resistance measurement range was 10 mΩ, and the number of display digits was 7. The display resolution was 0.01 μΩ, and the measurement accuracy was ±0.060% rdg. ±0.001% fs.

[0064] The ambient temperature of the thermostatic chamber was maintained at 25±3° C. Then, a durability test of the test piece was performed by maintaining the temperature of the thermostatic chamber 400 at 150° C. for 2000 hours. The volume resistivity of the test piece during this durability test was measured.

[0065] Figure 8 shows the volume resistivity of the test piece and its rate of change. In accordance with JIS-C2525, the volume resistivity of the test piece was measured at 20°C at 0 hours before the start of the test. At the end of the test, 2000 hours after the test, the volume resistivity of the test piece was measured at 150°C. The rate of change (resistance change rate) in the volume resistivity of the test piece when it was exposed to a high temperature of 150°C for 2000 hours was calculated, relative to the volume resistivity at 20°C.

[0066] The resistance values ​​of the test piece that was not subjected to SRO annealing and the test piece that was subjected to SRO annealing at 110°C were approximately 2.5 mΩ. In contrast, the resistance value of the test piece that was subjected to SRO annealing at 130°C to 210°C was approximately 5.9 mΩ. The difference between the two is due to the difference in the connection locations of the two platinum wires 430 when measuring the volume resistance value. Although the volume resistance value differs due to the slight difference in measurement conditions, this does not pose a problem when verifying the rate of change in volume resistance value.

[0067] 8, the rate of change in volume resistance value decreases when SRO annealing is performed. The rate of change in volume resistance value decreases as the temperature at which SRO annealing is performed increases.

[0068] The rate of change in volume resistivity of the test piece subjected to SRO annealing at 110°C was 0.22% smaller than the rate of change in volume resistivity of the test piece not subjected to SRO annealing when left at a high temperature of 150°C for 2000 hours.

[0069] As will be described later, the maximum measurement variability of the rate of change in volume resistance of resistor 110, which has more components than shunt resistor 300, is less than 0.2%. Therefore, the maximum measurement variability of shunt resistor 300 alone is expected to be less than 0.2%. The difference in the rate of change in volume resistance between the test piece subjected to SRO annealing at 110°C and the test piece not subjected to SRO annealing, 0.22%, is greater than the maximum measurement variability of 0.2%. Therefore, this experiment demonstrates that SRO annealing at 110°C is also effective in generating short-range ordered arrays.

[0070] As shown above, it can be seen that an effective temperature for SRO annealing is 110°C to 210°C, and that a sufficient annealing time is 12 hours. Assuming a measurement variation of 0.2%, when the SRO annealing temperature is 110°C to 210°C, the absolute value of the rate of change in volume resistivity is 0.02 to 1.06%. When the SRO annealing temperature is 110°C to 190°C, the absolute value of the rate of change in volume resistivity is 0.05 to 1.06%. When the SRO annealing temperature is 150°C to 190°C, the absolute value of the rate of change in volume resistivity is 0.05 to 0.48%.

[0071] <SROアニール> Next, the SRO annealing will be described in more detail.

[0072] The target temperatures for SRO annealing were set to six: 110°C, 130°C, 150°C, 170°C, 190°C, and 210°C. As shown in Figure 9, starting from 50°C, the specimen was heated to these target temperatures.

[0073] It took about 0.2 hours to reach the target temperatures of 110°C and 130°C. It took about 0.3 hours to reach the target temperature of 150°C. In the process of reaching the target temperatures of 170°C, 190°C, and 210°C, it took about 0.2 hours to reach 150°C, at which point short-range ordered arrays begin to effectively form, as described below. It took about 0.4 hours to reach the target temperatures of 170°C, 190°C, and 210°C.

[0074] Once these target temperatures were reached, the test pieces were maintained at these temperatures for 12 hours, including the temperature rise process, during which SRO annealing was performed. The volume resistivity was measured at 0 hours, 0.25 hours, 0.5 hours, 0.75 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, and 12 hours after the start of SRO annealing. The rate of change from the volume resistivity at the start of SRO annealing was calculated as the resistance change rate. The calculation results are shown in Figure 10.

[0075] Furthermore, for the test piece that underwent SRO annealing for 12 hours, the short-range ordered arrangement was deemed to have been sufficiently generated, and the volume resistivity of this test piece was normalized to 1. The ratio of this volume resistivity to the volume resistivity values ​​obtained at other times was regarded as the progress of SRO annealing. The experimental results are shown in Figure 10. The experimental results were also plotted as a graph, which is shown in Figure 11.

[0076] As shown in Figure 11, the rate of change in the annealing progress increases rapidly from the start of the temperature rise and gradually slows down after reaching the target temperature. The SRO annealing progress increases from 0% to approximately 70%, and then gradually increases to 80% and 90%. When the annealing progress reaches 80%, it is considered that short-range ordering has been generated in most areas of the test piece.

[0077] 12, when the SRO annealing temperature is 110°C, it takes about 5.6 hours to reach 80% annealing progress after increasing the temperature from 50°C. After increasing the temperature from 50°C to 110°C, it takes about 5.4 hours to reach 80% annealing progress while maintaining the temperature at 110°C.

[0078] When the SRO annealing temperature is 130°C, it takes approximately 4.7 hours for the annealing progress to reach 80% after increasing the temperature from 50°C. After increasing the temperature from 50°C to 130°C, it takes approximately 4.5 hours for the annealing progress to reach 80% while maintaining the temperature at 130°C.

[0079] When the SRO annealing temperature is 150°C, it takes approximately 3.0 hours for the annealing progress to reach 80% after increasing the temperature from 50°C. After increasing the temperature from 50°C to 150°C, it takes approximately 2.7 hours for the annealing progress to reach 80% while maintaining the temperature at 150°C.

[0080] When the SRO annealing temperature is 170°C, it takes approximately 1.4 hours for the annealing progress to reach 80% after increasing from 50°C. After increasing from 50°C to 150°C, it takes approximately 1.2 hours for the annealing progress to reach 80%. After increasing from 50°C to 170°C, it takes approximately 1.0 hour for the annealing progress to reach 80% while maintaining the temperature at 170°C.

[0081] When the SRO annealing temperature is 190°C, it takes approximately 1.4 hours for the annealing progress to reach 80% after increasing from 50°C. After increasing from 50°C to 150°C, it takes approximately 1.2 hours for the annealing progress to reach 80%. After increasing from 50°C to 190°C, it takes approximately 1.0 hour for the annealing progress to reach 80% while maintaining the temperature at 190°C.

[0082] When the SRO annealing temperature is 210°C, it takes approximately 2.9 hours to reach 80% annealing completion after increasing the temperature from 50°C. After increasing the temperature from 50°C to 150°C, it takes approximately 2.7 hours to reach 80% annealing completion. After increasing the temperature from 50°C to 210°C, it takes approximately 2.5 hours to reach 80% annealing completion while maintaining the temperature at 210°C.

[0083] Thus, the rate of annealing increases as the SRO annealing temperature increases from 110°C to 150°C, reaching its highest rate at 170°C. When the SRO annealing temperature increases to 190°C, the rate of annealing slows slightly. This result suggests that the formation of short-range ordered arrays proceeds effectively in the temperature range higher than 150°C and lower than 190°C.

[0084] From the above experimental results, when SRO annealing is performed in the temperature range of 170°C to 210°C, it takes 1.0 to 2.5 hours for the annealing progress to reach 80%. Specifically, when SRO annealing is performed in the temperature range of 200°C, it is thought that it takes 1.0 to 2.5 hours for the annealing progress to reach 80%.

[0085] When the SRO annealing temperature is 170° C., it takes about 1.2 hours from the time the SRO annealing temperature reaches 150° C., at which point the SRO annealing begins to work effectively, until the annealing progress reaches 80%.

[0086] When the SRO annealing temperature is 190° C., it takes about 1.2 hours from the time the SRO annealing temperature reaches 150° C. at which point it begins to work effectively until the annealing progress reaches 80%.

[0087] When the SRO annealing temperature is 210° C., it takes approximately 2.7 hours from the time the SRO annealing temperature reaches 150° C., at which point the SRO annealing begins to work effectively, until the annealing progress reaches 80%.

[0088] Furthermore, it takes approximately 1.0 to 5.4 hours for the annealing degree to reach 80% after the SRO annealing temperature is maintained at 110°C to 210°C. As mentioned above, when SRO annealing is performed at a temperature range of 170°C to 200°C, it is estimated that it takes 1.0 to 2.5 hours for the annealing degree to reach 80% after the SRO annealing temperature is maintained at 170°C to 200°C. Therefore, it takes approximately 1.0 to 5.4 hours for the annealing degree to reach 80% after the SRO annealing temperature is maintained at 110°C to 200°C.

[0089] After the SRO annealing temperature is maintained at 150°C to 190°C, where it is effective, it takes approximately 1.0 to 2.7 hours for the annealing progress to reach 80%. After the SRO annealing temperature is maintained at 150°C to 200°C, it is thought to take approximately 1.0 to 2.7 hours for the annealing progress to reach 80%.

[0090] Furthermore, the results of experiments at 170°C and 190°C, where SRO annealing is more effective, show that annealing times of approximately 10, 20, and 30 minutes are sufficient to achieve annealing progress of 50%, 60%, and 70%, respectively.

[0091] <Volume resistance value> Next, the volume resistivity will be described in more detail.

[0092] Test pieces that had not undergone SRO annealing and test pieces that had undergone SRO annealing at the target temperatures described above were prepared. These test pieces were left at a high temperature of 150°C for an extended period of time to undergo a durability test. Durability was evaluated by volume resistivity. The volume resistivity was measured at 0 hours, 250 hours, 500 hours, 750 hours, 1000 hours, 1500 hours, and 2000 hours. The measurement results are shown in Figure 13.

[0093] The rate of change from the starting volume resistance value was considered to be the rate of resistance change. The experimental results are shown in Figure 13. The experimental results were also plotted as a graph, which is shown in Figure 14.

[0094] 14, the test specimen exhibits a behavior in which the rate of resistance change increases as the time spent at a high temperature of 150°C increases. However, the magnitude of the rate of resistance change differs between the test specimen that was not subjected to SRO annealing and the test specimen that was subjected to SRO annealing.

[0095] In the case of a test piece that has not undergone SRO annealing, the absolute value of the resistance change rate exceeds 1.0% when left at a high temperature of 150°C for 2000 hours. In contrast, in the case of a test piece that has undergone SRO annealing, the absolute value of the resistance change rate is kept below 1.0%.

[0096] As shown in Figure 15, the absolute value of the resistance change rate of the test specimen decreases as the SRO annealing temperature increases from 110°C to 210°C. The absolute value of the resistance change rate of the test specimens where the SRO annealing temperature was 150°C to 210°C was kept below 0.3% even when left at a high temperature of 150°C for 2000 hours. The vertical axis of Figure 15 shows the rate of change in volume resistance from the volume resistance value before SRO annealing to the volume resistance value after 12 hours of SRO annealing. This is the value of the resistance change rate when SRO annealing was performed for 12 hours, as shown in Figure 10.

[0097] <Volume resistance of resistor> Next, the volume resistance of the resistor 110 will be described.

[0098] As a first group, seven resistors 110 were manufactured by the manufacturing method shown in FIG. 3, with SRO annealing performed at 175° C. for 24 hours, but without stress relief annealing in step S90.

[0099] As a second group, seven resistors 110 were manufactured by the manufacturing method shown in FIG. 3, but without performing the SRO annealing in step S70, and by performing stress relief annealing at 220° C. for two hours.

[0100] As a third group, eight resistors 110 were manufactured by the manufacturing method shown in FIG. 5, with stress relief annealing performed at 220° C. for two hours and SRO annealing performed at 175° C. for 24 hours.

[0101] As a fourth group, seven resistors 110 were manufactured by the manufacturing method shown in FIG. 3, with SRO annealing at 175° C. for 24 hours and stress relief annealing at 220° C. for 2 hours.

[0102] The resistors 110 included in the first to fourth groups were placed in a thermostatic chamber 400 and left at a high temperature of 150° C. for 2000 hours. The volume resistance of the shunt resistors 300 was measured at 0 hours, 250 hours, 500 hours, 1000 hours, 1500 hours, and 2000 hours.

[0103] The rate of change from the starting volume resistance value was considered to be the rate of resistance change. The experimental results are shown in Figures 16, 18, 20, and 22. In these figures, Ave indicates the average value of the resistance change rates of multiple resistors 110. 3σ indicates measurement variation. The experimental results were also plotted as graphs, which are shown in Figures 17, 19, 21, and 23. In these graphs, the average value of the resistance change rates of multiple resistors 110 is indicated by a solid line.

[0104] 16 and 17 show the resistance change rate of the shunt resistor 300 included in the resistor 110 of the first group. In the first group, the shunt resistor 300 is recrystallized by welding, so part of the short-range ordered array is destroyed. In addition, the distortion caused by welding is not removed.

[0105] Therefore, although the resistance change rate is smaller than that of the shunt resistor 300 that has not been annealed, it is larger than that of the test pieces in which SRO annealing has been performed at 170°C and 210°C, as shown in Figure 14. The resistance change rate after 2000 hours is -0.70%, with a measurement variation of 0.15%. The absolute value of the resistance change rate of the shunt resistor 300 of the resistor 110 that has only been subjected to SRO annealing is 0.55 to 0.85%.

[0106] 18 and 19 show the resistance change rate of the shunt resistors 300 included in the resistors 110 of the second group. In the second group, distortion due to welding is eliminated, but short-range ordered arrays are not generated in the shunt resistors 300.

[0107] Therefore, the longer the test time, the larger the resistance change rate. The long-term stability of the volume resistance value is impaired. The resistance change rate after 2000 hours is -0.40%, with a measurement variation of 0.12%. The absolute value of the resistance change rate of the shunt resistor 300 of the resistor 110 that was only subjected to strain relief annealing was 0.28 to 0.52%.

[0108] 20 and 21 show the resistance change rate of the shunt resistors 300 included in the resistors 110 of the third group. In the third group, the shunt resistors 300 are regularly arranged in a short distance, eliminating distortion caused by welding.

[0109] Therefore, the resistance change was the smallest compared to the other groups. The resistance change rate after 2000 hours was -0.11%, with a measurement variation of 0.09%. The absolute value of the resistance change rate of the shunt resistor 300 of the resistor 110 that underwent SRO annealing and strain relief annealing after welding was 0.02 to 0.20%.

[0110] 22 and 23 show the resistance change rate of the shunt resistor 300 included in the resistor 110 of the fourth group. In the fourth group, the shunt resistor 300 is recrystallized by welding, so that part of the short-range ordering is destroyed.

[0111] Therefore, the resistance change rate is slightly higher than that of Group 3, which underwent SRO annealing after welding. The resistance change rate after 2000 hours was -0.18%, with a measurement variation of 0.06%. The absolute value of the resistance change rate of the shunt resistor 300 of the resistor 110, which underwent SRO annealing before welding and stress relief annealing after welding, was 0.12 to 0.24%.

[0112] As shown above, in the case of resistor 110 that has undergone SRO annealing and strain relief annealing, the absolute value of the resistance change rate of shunt resistor 300 is suppressed to 0.02 to 0.24%. This resistance change rate is smaller than the absolute value of the resistance change rate of shunt resistor 300, 0.28 to 0.52%, in the case of resistor 110 that has undergone only strain relief annealing. This comparison shows that SRO annealing is effective.

[0113] <Action and effect> As explained above, by performing SRO annealing in the temperature range of 110°C or higher and 210°C or lower, a short-range ordered array is generated in the shunt resistor 300. However, taking into consideration the distinction from strain relief annealing, which is performed at a temperature of 200°C or higher, the temperature range for performing SRO annealing is 110°C or higher and lower than 200°C. Below, the effects of this temperature range will be explained.

[0114] When SRO annealing is performed at a temperature range of 110°C or higher and lower than 200°C, a short-range ordered arrangement is generated in the shunt resistor 300. This prevents the rate of change in the volume resistivity of the shunt resistor 300 from increasing even if the shunt resistor 300 is left in a high-temperature environment for a long period of time.

[0115] SRO annealing is performed by maintaining the temperature range of 110° C. or higher and lower than 200° C. for 1.0 to 5.4 hours, whereby the generation of short-range ordered ordering in the shunt resistor 300 progresses by 80% or more.

[0116] SRO annealing is performed at a temperature range of 150° C. or higher and lower than 190° C. In this way, short-range ordering is efficiently generated in the shunt resistor 300.

[0117] SRO annealing is performed by maintaining the temperature range of 150° C. or higher and lower than 190° C. for 1.0 to 2.7 hours, whereby the generation of short-range ordered ordering in the shunt resistor 300 progresses by 80% or more.

[0118] Resistor 110 including shunt resistor 300 and metal bus bar 200 is subjected to SRO annealing at a temperature range of 110°C or higher and lower than 200°C. Simultaneously, strain relief annealing is performed on resistor 110 at a temperature of 200°C or higher. This prevents the volume resistance of shunt resistor 300 in resistor 110 from increasing even when exposed to a high-temperature environment for a long period of time. Specifically, it is expected that the absolute value of the volume resistance of shunt resistor 300 will change by 0.02 to 0.24% when maintained at a constant temperature of 150°C for 2000 hours.

[0119] After the shunt resistor 300 is welded to the metal bus bar 200, SRO annealing is performed on the resistor 110. This prevents the short-range ordered array formed in the shunt resistor 300 from being destroyed by welding. In this case, the absolute value of the rate of change in the volume resistivity of the shunt resistor 300 when kept at a constant temperature of 150°C for 2000 hours is expected to be 0.02 to 0.20%.

[0120] <Modification> The disclosure of this specification is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and elements shown in the embodiments, and various modifications can be made. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and elements from the embodiments. The disclosure encompasses the substitution or combination of parts and elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. The disclosed technical scope is defined by the claims, and should be interpreted as including all modifications within the meaning and scope of the claims.

[0121] <Disclosure of technical ideas> This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be written in a multiple dependent form, with the subsequent clause referring to the preceding clause as an alternative. Furthermore, some clauses may be written in a multiple dependent form, referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0122] <Technical philosophy 1> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to remove residual strain generated in the cold-formed body by cold rolling; The method for producing a copper alloy sheet material comprises maintaining the cold-formed body from which the residual strain has been removed at a temperature in the range of 110°C or higher and lower than 200°C.

[0123] <Technical philosophy 2> The method for producing a copper alloy sheet according to Technical Concept 1, wherein the cold-formed body from which the residual strain has been removed is maintained at a temperature in the range of 110° C. or higher and lower than 200° C. for 1.0 to 5.4 hours.

[0124] <Technical philosophy 3> The method for producing a copper alloy sheet according to Technical Idea 1, wherein the cold-formed body from which the residual strain has been removed is maintained at a temperature in the range of 150°C or higher and lower than 200°C.

[0125] <Technical philosophy 4> The method for producing a copper alloy sheet according to Technical Concept 3, wherein the cold-formed body from which the residual strain has been removed is held at a temperature in the range of 150° C. or higher and lower than 200° C. for 1.0 to 2.7 hours.

[0126] <Technical philosophy 5> The method for producing a copper alloy sheet according to Technical Idea 1, wherein the cold-formed body from which the residual strain has been removed is maintained at a temperature in the range of 150°C or higher and lower than 190°C.

[0127] <Technical philosophy 6> The method for producing a copper alloy sheet according to Technical Concept 5, wherein the cold-formed body from which the residual strain has been removed is held at a temperature in the range of 150° C. or higher and lower than 190° C. for 1.0 to 2.7 hours.

[0128] <Technical philosophy 7> 7. The method for producing a copper alloy sheet according to any one of Technical Concepts 1 to 6, wherein a short-range ordered arrangement is generated in the cold-formed body from which the residual strain has been removed.

[0129] <Technical philosophy 8> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to remove residual strain generated in the cold-formed body by cold rolling; A method for producing a copper alloy sheet material, wherein a short-range ordered arrangement is generated in the cold-formed body from which the residual strain has been removed.

[0130] <Technical philosophy 9> The method for producing a copper alloy sheet according to any one of Technical Concepts 1 to 8, wherein the ingot is subjected to a homogenization heat treatment to homogenize the internal structure of the ingot.

[0131] <Technical Thought 10> The method for producing a copper alloy sheet according to any one of Technical Ideas 1 to 9, wherein the cold-formed body is maintained at a temperature in the range of 500°C or more and 850°C or less to remove residual strain caused in the cold-formed body by cold rolling.

[0132] <Technical Thought 11> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to remove residual strain generated in the cold-formed body by cold rolling; The cold-formed body from which the residual strain has been removed is maintained at a temperature range of 110°C or more and less than 200°C to produce a copper alloy sheet material (300), The copper alloy plate material is welded to a metal bus bar (200) to manufacture a resistor (110); The resistor is maintained at 200°C or higher to remove distortion caused in the copper alloy plate material by welding.

[0133] <Technical Thought 12> The method for producing a resistor according to Technical Idea 11, wherein the cold-formed body from which the residual strain has been removed is held at a temperature in the range of 110°C or higher and lower than 200°C for 1.0 to 5.4 hours to produce the copper alloy sheet material.

[0134] <Technical Thought 13> The method for manufacturing a resistor according to Technical Idea 11, wherein the cold-formed body from which the residual strain has been removed is maintained at a temperature range of 150°C or higher and lower than 200°C to manufacture the copper alloy sheet material.

[0135] <Technical Thought 14> The method for producing a resistor according to Technical Idea 13, wherein the cold-formed body from which the residual strain has been removed is held at a temperature in the range of 150°C or higher but lower than 200°C for 1.0 to 2.7 hours to produce the copper alloy sheet material.

[0136] <Technical Thought 15> The method for manufacturing a resistor according to Technical Idea 11, wherein the cold-formed body from which the residual strain has been removed is maintained at a temperature range of 150°C or higher and lower than 190°C to manufacture the copper alloy sheet material.

[0137] <Technical Thought 16> The method for producing a resistor according to Technical Idea 15, wherein the cold-formed body from which the residual strain has been removed is held at a temperature in the range of 150°C or higher and lower than 190°C for 1.0 to 2.7 hours to produce the copper alloy sheet material.

[0138] <Technical Thought 17> 17. The method for manufacturing a resistor according to any one of Technical Ideas 11 to 16, wherein a short-range ordered arrangement is formed in the cold-formed body from which the residual strain has been removed.

[0139] <Technical Thought 18> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to remove residual strain generated in the cold-formed body by cold rolling; A copper alloy sheet material (300) is manufactured in which a short-range ordered arrangement is generated in the cold-formed body from which the residual strain has been removed, The copper alloy plate material is welded to a metal bus bar (200) to manufacture a resistor (110); The resistor is maintained at 200°C or higher to remove distortion caused in the copper alloy plate material by welding.

[0140] <Technical Thought 19> 19. The method for manufacturing a resistor according to any one of Technical Ideas 11 to 18, wherein the ingot is subjected to a homogenization heat treatment to homogenize the internal structure of the ingot.

[0141] <Technical Thought 20> A method for manufacturing a resistor according to any one of Technical Ideas 11 to 19, wherein the cold-formed body is maintained at a temperature in the range of 500°C or higher and 850°C or lower to remove residual strain caused in the cold-formed body by cold rolling.

[0142] <Technical Thought 21> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to produce a copper alloy sheet material (300) in which residual strain generated in the cold-formed body by cold rolling is removed, The copper alloy plate material is welded to a metal bus bar (200) to manufacture a resistor (110); The resistor is maintained at 200°C or higher to remove distortion caused in the copper alloy plate material by welding, The resistor is maintained at a temperature of 110°C or higher and lower than 200°C.

[0143] <Technical Thought 22> The method for manufacturing a resistor according to Technical Idea 21, wherein the resistor is maintained at a temperature in the range of 110°C or higher and lower than 200°C for 1.0 to 5.4 hours.

[0144] <Technical Thought 23> The method for manufacturing a resistor according to Technical Idea 21, wherein the resistor is maintained at a temperature range of 150°C or higher and lower than 200°C.

[0145] <Technical Thought 24> The method for producing a resistor according to Technical Idea 23, wherein the resistor is maintained at a temperature in the range of 150°C or higher and lower than 200°C for 1.0 to 2.7 hours.

[0146] <Technical Thought 25> The method for manufacturing a resistor according to Technical Idea 21, wherein the resistor is maintained at a temperature range of 150°C or higher and lower than 190°C.

[0147] <Technical Thought 26> The method for producing a resistor according to Technical Idea 25, wherein the resistor is maintained at a temperature in the range of 150°C or higher and lower than 190°C for 1.0 to 2.7 hours.

[0148] <Technical Thought 27> 27. The method for manufacturing a resistor according to any one of Technical Ideas 21 to 26, wherein a short distance ordered array is formed in the copper alloy plate material to which the metal bus bar is welded.

[0149] <Technical Thought 28> a copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to produce a copper alloy sheet material (300) in which residual strain generated in the cold-formed body by cold rolling is removed, The copper alloy plate material is welded to a metal bus bar (200) to manufacture a resistor (110); The resistor is maintained at 200°C or higher to remove distortion caused in the copper alloy plate material by welding, A method for manufacturing a resistor, comprising forming a short-range ordered array in the copper alloy sheet material.

[0150] <Technical Thought 29> The method for manufacturing a resistor according to any one of Technical Ideas 21 to 28, wherein the ingot is subjected to a homogenization heat treatment to homogenize the internal structure of the ingot.

[0151] <Technical Thought 30> A method for manufacturing a resistor according to any one of Technical Ideas 21 to 29, wherein the cold-formed body is maintained at a temperature in the range of 500°C or higher and 850°C or lower to remove residual strain caused in the cold-formed body by cold rolling.

[0152] <Technical Thought 31> containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, and 0 to 0.10 mass% of Mg, with the balance being Cu and unavoidable impurities; A copper alloy sheet material having an absolute value of the rate of change in volume resistivity of 0.05 to 1.06% when kept at a constant temperature of 150°C for 2000 hours.

[0153] <Technical Thought 32> The copper alloy sheet material according to Technical Idea 31, wherein the absolute value of the rate of change in volume resistivity when kept at a constant temperature of 150°C for 2000 hours is 0.05 to 0.48%.

[0154] <Technical Thought 33> A copper alloy sheet (300) containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the balance being Cu and unavoidable impurities; a metal bus bar (200) to which the copper alloy plate material is welded, A resistor in which the absolute value of the rate of change in volume resistance when maintained at a constant temperature of 150°C for 2000 hours is 0.02 to 0.24%. [Explanation of symbols]

[0155] 10... control module, 20... sensor device, 30... control device, 100... current sensor, 200... metal bus bar, 300... shunt resistor

Claims

1. A copper alloy material containing 10.0 to 14.0 mass% of Mn, 1.0 to 4.0 mass% of Ni, 0 to 0.10 mass% of Al, 0 to 0.10 mass% of Mg, and the remainder being Cu and unavoidable impurities is prepared; The copper alloy material is melted and cast to produce an ingot; hot rolling the ingot to produce a hot-formed body; cold rolling the hot-formed body to produce a cold-formed body; The cold-formed body is maintained at a predetermined temperature range to remove residual strain generated in the cold-formed body by cold rolling; The cold-formed body from which the residual strain has been removed is held at a temperature range of 110 ° C. or higher and lower than 200 ° C. for 1.0 to 5.4 hours to produce a copper alloy sheet material (300); The copper alloy plate material is welded to a metal bus bar (200) to manufacture a resistor (110); The resistor is maintained at 200° C. or higher to remove distortion caused in the copper alloy plate material by welding.

2. The method for manufacturing a resistor according to claim 1 , wherein the copper alloy sheet is manufactured by holding the cold-formed body from which the residual strain has been removed at a temperature in the range of 150° C. or higher and lower than 200° C.

3. The method for manufacturing a resistor according to claim 2, wherein the cold-formed body from which the residual strain has been removed is held at a temperature range of 150°C or higher and lower than 200°C for 1.0 to 2.7 hours to manufacture the copper alloy sheet material.

4. The method for manufacturing a resistor according to claim 1, wherein the copper alloy sheet is manufactured by holding the cold-formed body from which the residual strain has been removed at a temperature in the range of 150°C or higher and lower than 190°C.

5. The method for producing a resistor according to claim 4, wherein the cold-formed body from which the residual strain has been removed is held at a temperature range of 150°C or higher and lower than 190°C for 1.0 to 2.7 hours to produce the copper alloy sheet material.

6. The method for manufacturing a resistor according to any one of claims 1 to 5, further comprising forming a short-range ordered arrangement in the cold-formed body from which the residual strain has been removed.

7. The method for manufacturing a resistor according to claim 1 , wherein the ingot is subjected to a homogenization heat treatment to homogenize the internal structure of the ingot.

8. The method for manufacturing a resistor according to claim 1 , wherein the cold-formed body is maintained at a temperature in the range of 500° C. to 850° C., thereby removing residual strain generated in the cold-formed body by cold rolling.

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