Shunt Resistors

Abstract

The present invention provides a shunt resistor that can easily reduce resistance. The shunt resistor includes a first resistor 10; two substrates 11 that clamp the first resistor 10 and are joined to the first resistor 10 by welding Y1; and a second resistor 12 that is joined to the two substrates 11 at a position different from the first resistor 10 by welding Y2. The second resistor 12 is in contact with the first resistor 10 and is joined to the two substrates by welding Y2.

Description

Technical Field

[0001] The present invention relates to a shunt resistor. Background Art

[0002] A well-known shunt resistor is a shunt resistor described in Japanese Patent Application Publication No. 2009-244065. Figure 7 As shown, the shunt resistor 100 includes two plate-like substrates 102 sandwiching a resistor 101 and joined to the resistor 101 by welding 101a, and a measurement terminal portion 103 joined to the substrate 102 by welding 103a. Here, the symbol 102a refers to a circular screw hole for the shaft of a screw (not shown) to pass through. Summary of the invention

[0003] Technical problem to be solved by the invention

[0004] Here, the shunt resistor as described above generates heat when current passes through it, and therefore, the resistance value of the resistor changes with the heating temperature. Therefore, in order not to increase the heating temperature, it is necessary to reduce the resistance value of the resistor. For example, when a large current of 400A passes through the shunt resistor, the resistance value of the resistor is preferably about 100μΩ, and when a large current of 1000A passes through the shunt resistor, the resistance value of the resistor is preferably about 30μΩ to 50μΩ.

[0005] In order to reduce the resistance value of the resistor, it is considered to narrow the width of the resistor (refer to Figure 7 (b)). For example, to adjust the resistance value of the resistor to 100μΩ, the width of the resistor (reference Figure 7 (b)) is adjusted to 8mm; and to adjust the resistance value of the resistor to 30μΩ~50μΩ, the width of the resistor 101 (reference Figure 7 (b)) Adjust to about 3 mm.

[0006] However, when the width of the resistor body (reference Figure 7 (b)) When the diameter is narrowed, it is very difficult to join the resistor to the two substrates by welding in a state where the resistor is sandwiched between the two substrates. Therefore, it is very difficult to reduce the resistance value.

[0007] On the other hand, it is known that the resistance value of a resistor varies with the volume of the resistor itself. Figure 7 As shown in FIG. 1 , a concave recess 101 b is provided in the resistor 101 , and the resistance value of the resistor 101 is adjusted by reducing the volume of the resistor 101 .

[0008] However, in the above method, although the resistance value can be increased, the resistance value cannot be reduced. Therefore, there is a problem that the resistance value cannot be reduced.

[0009] Therefore, in view of the above problems, an object of the present invention is to provide a shunt resistor whose resistance value can be simply and easily reduced.

[0010] Means of solving the problem

[0011] The above-mentioned object of the present invention is achieved by the following means: Here, the component symbols in brackets indicate the following embodiments, but the present invention is not limited thereto.

[0012] According to one embodiment of the present invention, a shunt resistor includes a first resistor body; two substrates that clamp the first resistor body and are joined to the first resistor body by welding; and a second resistor body that is joined to the two substrates by welding at a position different from the first resistor body.

[0013] Furthermore, according to another embodiment of the present invention, in the above-mentioned shunt resistor, the second resistor body is in contact with the first resistor body and is bonded to the two base materials by welding.

[0014] On the other hand, according to another embodiment of the present invention, in the above-mentioned shunt resistor, the second resistor is bonded to the two base materials by welding in a state where the second resistor is located close to the first resistor and does not contact the first resistor.

[0015] Effects of the Invention

[0016] The effects of the invention will be described with reference to the component symbols in the drawings. Here, the component symbols in parentheses indicate the embodiments described later, but the present invention is not limited thereto.

[0017] According to an embodiment of the present invention, the second resistor is bonded to the two substrates sandwiching the first resistor and bonded to the first resistor by welding at a position different from the first resistor, so that the bonding area of ​​the resistors (the first resistor, the second resistor) bonded to the two substrates is increased. Therefore, the resistance value can be reduced.

[0018] Then, according to the present invention, the resistance value can be reduced by simply bonding the second resistor to the two substrates at a position different from the first resistor by welding, so the resistance value can be reduced simply.

[0019] Furthermore, when the second resistor is joined to the two substrates by welding, as in another embodiment of the present invention, the second resistor (12, 12B, 12C) is preferably joined to the two substrates by welding while being in contact with the first resistor. Alternatively, as in another embodiment of the present invention, the second resistor (12D) is preferably joined to the two substrates by welding while being close to the first resistor and not in contact with the first resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 (a) is a perspective view of a shunt resistor according to an embodiment of the present invention, and (b) is a plan view of the shunt resistor according to the same embodiment.

[0021] Figure 2 is a plan view of a shunt resistor according to another embodiment.

[0022] Figure 3 is a plan view of a shunt resistor according to another embodiment.

[0023] Figure 4 FIG. 4 is a bottom view of a shunt resistor according to another embodiment.

[0024] Figure 5 is a plan view of a shunt resistor according to another embodiment.

[0025] Figure 6 (a) is a plan view of a substrate of one embodiment, (b) is a plan view of a first resistor and a second resistor of one embodiment, and (c) is a plan view showing experimental conditions of a shunt resistor of one embodiment.

[0026] Figure 7 (a) is a perspective view of a known shunt resistor, and (b) is a plan view of a known shunt resistor.

[0027] Explanation of symbols

[0028] 1, 1A, 1B, 1C, 1D: Shunt resistor

[0029] 10: First resistor

[0030] 11: Base material

[0031] 12, 12B, 12C, 12D: second resistor

[0032] 13: Measurement terminal

[0033] Y2, Y2B, Y2C, Y2D: welding DETAILED DESCRIPTION

[0034] Here, in the following description, when describing the up, down, left, and right directions, it refers to the up, down, left, and right directions when viewed from the front of the figure.

[0035] The shunt resistor according to the present embodiment is used for a high voltage battery used in an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV), or is used to measure the current value of a current path where a large current flows from an inverter to a motor circuit. Figure 1 As shown, the shunt resistor 1 is constructed to include a first resistor body 10, two substrates 11 that clamp the first resistor body 10 and are formed into a whole with the first resistor body by welding Y1, a second resistor body 12 that is joined to the two substrates 11 by welding Y2 at a position different from the first resistor body 10, and measurement terminals 13 that are erected and fixed on the upper surfaces 11a of the two substrates 11 by welding Y3.

[0036] The first resistor 10 is Figure 7 The resistor body 101 is the same object as shown Figure 1 As shown in (b), for example, it is a thick plate with a thickness of about 3 mm to 5 mm, formed into a short rectangular shape consisting of an upper surface 10a, a lower surface 10b, an upper side surface 10c, a lower side surface 10d, a left side surface 10e, and a right side surface 10f, and is formed with Figure 7 The first resistor 10 is formed of, for example, a Cu-Mn alloy, a Cu-Ni alloy, a Ni-Cr alloy, or the like.

[0037] Then, the first resistor 10 thus formed is Figure 1 As shown, the substrate 11 on the left side of the figure is joined to the left side surface 10e of the first resistor 10 by welding Y1, and the substrate 11 on the right side of the figure is joined to the right side surface 10f of the first resistor 10 by welding Y1. Therefore, a pair of substrates 11 sandwich the first resistor 10 and are formed integrally with the first resistor 10.

[0038] The substrate 11 is Figure 7 The substrate 102 is shown as an object, referred to as a bus, made of a metal such as copper. Figure 1 As shown, for example, it is a thick plate with a thickness of about 3 mm to 5 mm, and is formed into a long rectangle consisting of an upper surface 11a, a lower surface 11b, an upper side surface 11c, a lower side surface 11d, a side surface 11e, and another side surface 11f. The length direction of this substrate 11 is along the other side surface 11f (the side opposite to the joint portion of the first resistor 10), and a circular screw hole 11g is formed to pass through the shaft of a screw not shown in the figure and penetrate in the vertical direction.

[0039] Next, the substrate 11 thus formed is Figure 1 As shown, the side surface 11e of the substrate 11 located on the left side of the figure is joined to the left side surface 10e of the first resistor 10 by welding Y1, and the side surface 11e of the substrate 11 located on the right side of the figure is joined to the right side surface 10f of the first resistor 10 by welding Y1. Therefore, a pair of substrates 11 are formed integrally with the first resistor 10 by welding Y1.

[0040] The second resistor 12 is Figure 1 As shown, it is formed into a short rectangular thick plate having a thickness of about 3 mm to 5 mm, for example, and is formed of, for example, a Cu-Mn alloy, a Cu-Ni alloy, a Ni-Cr alloy, or the like.

[0041] Next, the second resistor 12 thus formed is Figure 1 As shown in (b), the upper surface 12a of the second resistor 12 is in the same plane as the upper surface 10a of the first resistor 10; in order to make the lower side surface 12b of the second resistor 12 contact the upper side surface 10c of the first resistor 10, the lower side surface 12b of the second resistor 12 is joined to the upper side surface 11c of the pair of substrates 11 by welding Y2. Therefore, the pair of substrates 11 and the second resistor 12 are formed into one body by welding Y2.

[0042] Determine terminal 13 and Figure 7 The measurement terminal portion 103 shown is the same object, and can be mounted on a printed circuit board for current detection, and is formed of copper, tin plating, etc. Figure 1 As shown, they are respectively fixed upright on two base materials 11 by welding Y3.

[0043] Next, according to the present embodiment described above, the second resistor 12 is joined by welding Y2 at a position different from the first resistor 10 by the two base materials 11 sandwiching the first resistor 10 and forming a whole with the first resistor 10 by welding Y1, so that the joining area of ​​the resistors (the first resistor 10 and the second resistor 12) joined to the two base materials 11 is increased. Therefore, the resistance value can be reduced.

[0044] That is, in a battery for high voltage power use, or for measuring the current value of a current path where a large current flows from an inverter to a motor circuit, a large current flows through the two substrates 11, but since the contact area of ​​the resistor (the first resistor 10, the second resistor 12) increases, the current path increases accordingly, so the current is easier to pass through the resistor (the first resistor 10, the second resistor 12) than in the conventional method, and therefore, the heating temperature of the resistor (the first resistor 10, the second resistor 12) can be lower than in the conventional method. Therefore, the resistance value can be reduced.

[0045] Next, based on this embodiment, the width W10 of the first resistor 10 (refer to Figure 1 (b)) does not need to be narrowed, that is, it can be used with the same length as the conventional one (ref. Figure 1 (b) Figure 7 (b)), the resistance value can be reduced by simply bonding the second resistor 12 to the two substrates 11 at a position different from the first resistor 10 by welding Y2, so the resistance value can be reduced simply and easily.

[0046] In addition, according to this embodiment, when adjusting the resistance value, if the resistance value is to be increased, the following method can be used: Figure 7 In the method shown, a concave depression is provided in the first resistor 10 and / or the second resistor 12, and the resistance value can be increased by reducing the volume of the first resistor 10 and / or the second resistor 12. On the other hand, if the resistance value is to be reduced, it is only necessary to join a new second resistor with a larger area than the second resistor 12 to the two substrates 11 by welding Y2.

[0047] Therefore, the resistance value can be adjusted simply and easily according to this embodiment.

[0048] Furthermore, if the resistance value is reduced, the heat loss can be reduced because the heat generation temperature of the resistor (the first resistor 10 and the second resistor 12) is lower than that of the conventional resistor.

[0049] Next, when installing the current detection printed circuit board to the measurement terminal 13, heat dissipation fins are required. However, if the resistance value is reduced, the heating temperature of the resistor (first resistor 10, second resistor 12) can be lower than the traditional one, so the heat dissipation fins can be miniaturized or removed.

[0050] At this time, the shape of the shunt resistor 1 shown in this embodiment is only an example, and various deformations and changes can be made within the scope of the main idea of ​​the present invention described in the scope of the claims. For example, in this embodiment, the first resistor 10 and the second resistor 12 are shown as being separately set, but are not limited to this, and can also be integrated. However, the separate setting method is more preferable because when adjusting the resistance value, if the resistance value is to be reduced, only the second resistor 12 needs to be changed, so it is better.

[0051] On the other hand, the shape of the second resistor 12 can be any shape, and the position where it is joined to the two substrates 11 is not limited to Figure 1 The position shown in FIG. 1 can be any position. For example, it can be Figure 2 The shunt resistor shown is of the form 1A. This point will refer to Figure 2 Here, Figure 1 The same components of the shunt resistor 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0052] Figure 2 The shunt resistor 1A shown with Figure 1 The difference of the shunt resistor 1 shown in FIG. 1 is that an additional second resistor 12 is connected, and the rest is the same. Figure 2 As shown, the newly added second resistor 12 has an upper surface 12a of the second resistor 12 and an upper surface 10a of the first resistor 10 in the same plane, and the upper side surface 12c of the second resistor 12 is joined to the lower side surface 11d of a pair of substrates 11 by welding Y2, so that the upper side surface 12c of the second resistor 12 is in contact with the lower side surface 10d of the first resistor 10, and thus joined to the pair of substrates 11. Therefore, the pair of substrates 11 and the pair of second resistors 12 are formed into one body by welding Y2.

[0053] Even so, the current path increases, and the current flowing through the resistor (first resistor 10, second resistor 12) flows more easily than in the conventional case. Therefore, the heating temperature of the resistor (first resistor 10, second resistor 12) can be lower than in the conventional case, so the resistance value can be reduced. Here, when adjusting the resistance value, when the resistance value is to be lowered, it is not necessary to replace the second resistor 12, but only to replace the second resistor 12. Figure 2 As shown, another second resistor 12 may be bonded to the two substrates 11 by welding Y2.

[0054] In addition, it can also be formed as Figure 3 The shunt resistor shown is 1B. This point will refer to Figure 3 Here, Figure 1 The same components of the shunt resistor 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0055] Figure 3 The shunt resistor 1B shown with Figure 1 The difference between the shunt resistor 1 shown in FIG. 1 and FIG. 2 is only in the shape of the second resistor 12 and the position of the connection, and the rest is the same. Figure 3As shown, the second resistor body 12B is formed to be approximately rectangular in a plan view. A first recess 12Ba1 shaped like a U in a plan view is provided on the left side surface 12Ba side, and a second recess 12Bb1 shaped like a U facing right in a plan view is provided on the right side surface 12Bb. The second resistor body 12B formed in this way is disposed on the upper surface 10a of the first resistor body 10 so as to be perpendicular to the first resistor body 10. The portions (the left side surface 12Ba side and the right side surface 12Bb side of the second resistor body 12B) in contact with the pair of base materials 11 are joined by soldering Y2B. Thus, the pair of base materials 11 are integrally formed with the second resistor body 12B by soldering Y2B. Here, at this time, the second resistor body 12B is in contact with the measurement terminal 13, and a pair of measurement terminals 13 are respectively provided in the first recess 12Ba1 and the second recess 12Bb1 to prevent the measurement terminal 13 from measuring an incorrect current value.

[0056] Even so, the current path increases, and the current flowing through the resistor bodies (the first resistor body 10 and the second resistor body 12B) flows more easily than in the conventional case. Therefore, the heat generation temperature of the resistor bodies (the first resistor body 10 and the second resistor body 12B) can be made lower than in the conventional case, and thus the resistance value can be reduced.

[0057] On the other hand, it can also be formed as Figure 4 the shunt resistor 1C shown. This will be described in detail with reference to Figure 4 Here, the same components as those of the shunt resistor 1 shown in Figure 1 will be given the same component symbols, and their detailed description will be omitted.

[0058] Figure 4 The difference between the shunt resistor 1C shown in Figure 1 and the shunt resistor 1 shown in Figure 4 is only in the shape of the second resistor body and the joining position, and the rest are the same. That is, as shown in Figure 4 , the second resistor body 12C is formed to be approximately rectangular in a plan view. The second resistor body 12C formed in this way is disposed on the lower surface 10b of the first resistor body 10 so as to be perpendicular to the first resistor body 10. The portions (the left side surface 12Ca side and the right side surface 12Cb side of the second resistor body 12C) in contact with the pair of base materials 11 are joined by soldering Y2C. Thus, the pair of base materials 11 are integrally formed with the second resistor body 12C by soldering Y2C.

[0059] Even so, the current path increases, and the current flowing through the resistor bodies (the first resistor body 10 and the second resistor body 12C) flows more easily than in the conventional case. Therefore, the heat generation temperature of the resistor bodies (the first resistor body 10 and the second resistor body 12C) can be made lower than in the conventional case, and thus the resistance value can be reduced.

[0060] So far, Figure 1 The shunt resistor 1 shown, Figure 2 The shunt resistor shown is 1A, Figure 3 The shunt resistor 1B shown, Figure 4 In any of the shunt resistors 1C shown, the first resistor 10 is in contact with the second resistor 12, 12B, 12C. Figure 5 The shunt resistor 1D shown may also be disconnected. This will be referred to Figure 5 Here, Figure 1 The same components of the shunt resistor 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0061] Figure 5 The shunt resistor 1D shown with Figure 1 The difference between the shunt resistor 1 shown in FIG. 1 and FIG. 2 is only in the shape of the second resistor body and the position of the connection, and the rest is the same. Figure 5 As shown, the second resistor 12D is formed in a downward U-shaped shape in a planar view, and the upper surface 12Da of the second resistor 12D is in the same plane as the upper surface 11a of the pair of substrates 11, and the lower side surface 12Db of the second resistor 12D is joined to the upper side surface 11c of the pair of substrates 11 by welding Y2D. Therefore, the pair of substrates 11 are formed integrally with the second resistor 12D by welding Y2D. Here, at this time, although the first resistor 10 and the second resistor 12D are located in a nearby position, they are not in a contacting state.

[0062] Even so, the current path increases, and the current flowing through the resistor (the first resistor 10 and the second resistor 12D) flows more easily than in the conventional case. Therefore, the heating temperature of the resistor (the first resistor 10 and the second resistor 12D) can be lower than in the conventional case, so the resistance value can be reduced.

[0063] Here, the shunt resistors 1, 1A, 1B, 1C, and 1D exemplified above are also used as shunt resistors for fuses that require low resistance.

[0064] Example

[0065] Next, the present invention will be described in further detail by using examples.

[0066] Use 10 of each Figure 1 The resistance value was measured using the shunt resistor 1 shown and a known shunt resistor.

[0067] Regarding the size of the shunt resistor 1, the substrate 11 is as follows Figure 6As shown in (a), the lateral length of the substrate 11 is 38 mm (the distance from the other side 11f of the substrate 11 to the side 11e), the longitudinal length of the substrate 11 is 18 mm (the distance from the upper side 11c of the substrate 11 to the lower side 11d), the distance from the upper side 11c of the substrate 11 to the center point of the screw hole 11g of the substrate 11 is 9 mm, the distance from the other side 11f of the substrate 11 to the center point of the screw hole 11g of the substrate 11 is 12 mm, the diameter of the screw hole 11g of the substrate 11 is 8.0 mm, and the thickness is 3.0 mm.

[0068] In addition, the first resistor 10 is Figure 6 As shown in (b), a material having a horizontal length of 8.0 mm, a vertical length of 18 mm, and a thickness of 2.0 mm is used. Figure 6 As shown in (b), an object with a horizontal length of 16.0 mm, a vertical length of 2.0 mm, and a thickness of 2.0 mm is used.

[0069] Here, the substrate 11 of the conventional shunt resistor is the same as the first resistor 10 except that the second resistor 12 is not included.

[0070] Next, for the shunt resistor 1 formed into such a size, as Figure 6 As shown in (c), the current flows from the right side to the left side in the figure, and the current is applied to the other side 11f of the substrate 11 (see the black dot in the figure), and the measurement terminal 13 is set to a voltage detection interval of 12mm. Here, the known shunt resistor is also tested under the same conditions.

[0071] Under such conditions, the shunt resistor 1 and a known shunt resistor were respectively placed on a resistance measurement jig manufactured by Sankor Co., Ltd., and the resistance was measured using a RM3543RESISTANCE HiTESTER resistance measuring machine manufactured by HIOKI Co., Ltd. The results are shown in Table 1.

[0072] Table 1

[0073]

[0074] As shown in Table 1 above, the resistance value of any shunt resistor 1 is lower than the resistance value of the known shunt resistor. In addition, the resistance value of the known shunt resistor is averaged to obtain 0.09949 mΩ. In comparison, the average resistance value of the shunt resistor 1 is 0.08446 mΩ. It is known that the resistance value of the shunt resistor 1 can be reduced by about 15% compared to the known shunt resistor.

[0075] It can be seen that the resistance value can be reduced by using the shunt resistor according to this embodiment. Therefore, the resistance value can be reduced simply and easily by using this embodiment.

Claims

1. A shunt resistor, characterized in that: include A first resistor having a rectangular shape; two substrates, sandwiching the first resistor and being bonded to the first resistor by welding; as well as A second resistor having a rectangular shape is joined to the two base materials by welding at a position different from that of the first resistor. in The upper surface of the first resistor and the upper surface of the second resistor are in the same plane, and the lower side surface of the second resistor is joined to the upper side surfaces of the two substrates by welding so that the lower side surface of the second resistor contacts the upper side surface of the first resistor.

Images