Shunt resistor and shunt resistor arrangement

Abstract

The present invention relates to a shunt resistor and a shunt resistor device. The shunt resistor (1) has an electrode member (10). The electrode member (10) includes a contact site (10a) that contacts a resistor body (5) and a slit (20) formed at the contact site (10a).

Description

TECHNICAL FIELD

[0001] The present application relates to a shunt resistor and a shunt resistor device. BACKGROUND

[0002] There is a shunt resistor that makes current flow to a resistance body and detects the current size from the voltage across both ends thereof (for example, refer to Patent Literature 1). Such a shunt resistor is provided with a circular plate-shaped resistance body and two electrodes formed on both surfaces of the resistance body. One of the two electrodes is connected to a wiring (pad), and the other is connected to a bonding wire.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2018-170478 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] The electrode connected to the bonding wire has a potential distribution. Thus, the detected resistance value and the temperature coefficient of resistance (T.C.R) of the shunt resistor sometimes change due to the deviation of the connection position of the bonding wire. The temperature coefficient of resistance is an index indicating the rate of change in resistance value caused by temperature.

[0008] Therefore, an object of the present application is to provide a shunt resistor and a shunt resistor device capable of suppressing the deviation of the characteristics of the shunt resistor caused by the connection position of the wiring for voltage detection.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] In one aspect, a shunt resistor provided with an electrode member composed of an electrically conductive material is provided. The electrode member includes a contact site in contact with a resistance body and a slit formed at the contact site.

[0011] In one aspect, the slit extends in a direction perpendicular to the direction of current flow.

[0012] In one aspect, the contact site has a first surface adjacent to the resistance body and a second surface on the opposite side of the first surface, and the slit is a through-hole connected to the first surface and the second surface.

[0013] In one aspect, a shunt resistor device is provided, including: a resistor body; an electrode member having a contact site in contact with the resistor body; and a voltage detection wiring connected to the electrode member. The electrode member has a slit formed at the contact site, and the voltage detection wiring is disposed in a first wiring region between the slit and a slit-side end portion of the electrode member.

[0014] In one aspect, the shunt resistor device has a current wiring connected to the electrode member, the current wiring being disposed in a second wiring region on the side opposite the first wiring region across the slit.

[0015] In one aspect, the slit extends in a direction perpendicular to a current direction.

[0016] In one aspect, the contact site has a first face adjacent to the resistor body and a second face opposite the first face, and the slit is a through-hole connecting the first face and the second face.

[0017] Inventive Effects

[0018] According to the present application, by forming a slit at a contact site, a deviation in characteristics of a shunt resistor caused by a connection position of a wiring for voltage detection can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view showing one embodiment of a shunt resistor for current detection.

[0020] Figure 2 is a perspective view showing one embodiment of a shunt resistor for current detection.

[0021] Figure 3 is a view showing one embodiment of a mounting pad pattern.

[0022] Figure 4 is a view showing a shunt resistor device mounted on the mounting pad pattern shown in Figure 3

[0023] Figure 5 is a view for explaining measurement positions of a resistance value and a T.C.R. in order to verify effectiveness of the shunt resistor having a slit according to the present embodiment.

[0024] Figure 6 is a graph showing a change in a resistance value of a shunt resistor based on a measurement position.

[0025] Figure 7 is a graph showing a change in a T.C.R. of a shunt resistor based on a measurement position. ​

[0026] Figure 8 is a view showing another embodiment of the shunt resistor.

[0027] Figure 9 is a view showing another embodiment of the shunt resistor.

[0028] Figure 10 is a view showing a shunt resistor shown in Figure 9 mounted on a mounting pad pattern shown in Figure 3 is a view showing one embodiment of a shunt resistor device configured by mounting the shunt resistor shown in

[0029] Figure 11 is a view showing another embodiment of a shunt resistor device configured by mounting the shunt resistor shown in Figure 9 on a mounting pad pattern shown in Figure 3 is a view showing another embodiment of a shunt resistor device configured by mounting the shunt resistor shown in DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the present application will be described with reference to the drawings. Note that, in the drawings described below, the same or equivalent structural elements are denoted by the same reference numerals, and repetitive description is omitted.

[0031] Figure 1 and Figure 2 is a perspective view showing one embodiment of a shunt resistor for current detection. As shown in Figure 1 and Figure 2 , the shunt resistor 1 includes: a resistance body 5 having a plate shape (a thin plate shape) with a prescribed thickness and width; an electrode 6 having a plate shape (a thin plate shape) made of an electrically conductive material; and an electrode member 10 made of an electrically conductive material.

[0032] As one example of the material of the resistance body 5, a low-resistance alloy material such as a Cu-Mn-Ni-based alloy, a Ni-Cr-based alloy, or the like is given. As one example of the material of the electrode 6 and the electrode member 10, copper (Cu) as a highly conductive metal is given.

[0033] The resistance body 5 has a first resistance body surface 5a and a second resistance body surface 5b as a surface opposite to the first resistance body surface 5a. The electrode member 10 is connected to the first resistance body surface 5a, and the electrode 6 is connected to the second resistance body surface 5b. That is, the electrode 6, the resistance body 5, and the electrode member 10 are stacked in this order in the thickness direction of the shunt resistor 1.

[0034] In Figure 1 and Figure 2 , the thickness direction of the shunt resistor 1 is a direction parallel to the vertical direction. The first direction is the length direction of the shunt resistor 1. The second direction is the width direction of the shunt resistor 1, and is a direction perpendicular to the first direction.

[0035] The electrode member 10 has a rectangular main body portion 11 and a terminal portion 14 extending in a thickness direction from the main body portion 11. The main body portion 11 and the terminal portion 14 are a unitarily formed member.

[0036] The electrode member 10 (more specifically, the main body portion 11) has a contact site 10a that contacts the resistance body 5. By moving the electrode member 10 in a direction indicated by a white hollow arrow shown in Figure 1 , the contact site 10a of the electrode member 10 is connected to the resistance body 5 (see Figure 2 ). The terminal portion 14 is disposed on the opposite side of the contact site 10a with respect to a center line CL of the electrode member 10. The center line CL is an imaginary line that extends in parallel with the second direction of the shunt resistor 1 and bisects the electrode member 10.

[0037] The terminal portion 14 and the electrode 6 (and the resistance body 5) are disposed apart from each other in a first direction of the shunt resistor 1. The first direction is parallel with a current direction of a current that passes through the shunt resistor 1.

[0038] The electrode member 10 can be connected to the first resistance body surface 5a of the resistance body 5 by welding, soldering, metal nano particles (silver paste using silver nano particles, copper paste using copper nano particles), or the like. The electrode 6 can also be connected to the second resistance body surface 5b of the resistance body 5 by the same connection means. The terminal portion 14 and the electrode 6 are subjected to surface treatment such as Sn plating or Ni plating in order to enable soldering installation.

[0039] As shown in Figure 1 and Figure 2 , the electrode member 10 has a slit 20 formed at the contact site 10a. The slit 20 is an elongated hole that extends in a direction perpendicular to the current direction (i.e., a direction parallel with the second direction).

[0040] The slit 20 penetrates from the surface of the electrode member 10 to the resistance body 5. More specifically, the contact site 10a has a first face 21 adjacent to the resistance body 5 and a second face 22 on the opposite side of the first face 21, and the slit 20 is a through hole that connects these first face 21 and second face 22.

[0041] The electrode member 10 has both end portions 23 and 24 in the first direction. The end portion 23 is a slit side end portion adjacent to the slit 20, and the end portion 24 is an opposite side end portion apart from the slit 20. Thus, the distance between the slit 20 and the slit side end portion 23 is smaller than the distance between the slit 20 and the opposite side end portion 24.

[0042] As shown in Figure 2As shown, a wiring region Al (a frame surrounded by a broken line) between the slit 20 and the slit side end portion 23, to which the voltage detection wiring 25 is connected at the time of mounting. The voltage detection wiring 25 is a wiring (terminal) for detecting a potential difference at the resistance body 5 (a potential difference generated between the first resistance body surface 5a and the second resistance body surface 5b). The resistance body 5, the electrode member 10, and the voltage detection wiring 25 connected to the electrode member 10 constitute a shunt resistor device 100.

[0043] In one embodiment, the voltage detection wiring 25 can be a bonding wire. In this case, the wiring region Al of the electrode member 10 (more specifically, the contact portion 10a) is subjected to surface treatment capable of bonding (for example, plating of NiP, plating of Ni, or the like).

[0044] Figure 3 FIG. 1 is a view showing one embodiment of a mounting land pattern. Figure 4 FIG. 2 is a view showing a shunt resistor device 100 mounted on the mounting land pattern shown in FIG. 1. Figure 3 FIG. 2 is a view showing a shunt resistor device 100 mounted on the mounting land pattern shown in FIG. 1. Figure 3 FIG. 3 is a view showing a shunt resistor device 100 mounted on the mounting land pattern shown in FIG. 1. Figure 4 As shown, a wiring region Al (a frame surrounded by a broken line) between the slit 20 and the slit side end portion 23, to which the voltage detection wiring 25 is connected at the time of mounting. The voltage detection wiring 25 is a wiring (terminal) for detecting a potential difference at the resistance body 5 (a potential difference generated between the first resistance body surface 5a and the second resistance body surface 5b). The resistance body 5, the electrode member 10, and the voltage detection wiring 25 connected to the electrode member 10 constitute a shunt resistor device 100.

[0045] The current passage patterns (Japanese: Denen pattern) 30, 31 are formed on a circuit substrate such as a printed substrate, which is not shown. The terminal portion 14 and the electrode 6 are each connected (bonded) to the current passage patterns 30, 31 by means of soldering or the like. A current passage is formed by the current passage pattern 30, the shunt resistor 1, and the current passage pattern 31. In the present embodiment, a voltage measurement device 26 can be used to measure a potential difference between the voltage detection wiring 25 and the lead-out wire 33 (i.e., a potential difference at the resistance body 5). A current value is calculated by measurement of the relevant potential difference. The calculated current value is used for control of various devices mounted on a car, for example.

[0046] Figure 5 FIG. 6 is a view for explaining measurement positions of resistance values and T.C.R. for verifying effectiveness of the shunt resistor 1 of the present embodiment, which is formed with the slit 20. Figure 6 FIG. 7 is a graph showing changes in resistance values of the shunt resistor 1 based on the measurement positions. Figure 7 FIG. 8 is a graph showing changes in T.C.R. of the shunt resistor 1 based on the measurement positions.

[0047] Figure 6Simulation results of resistance values ​​are shown when the width of slit 20 is varied (1.5 mm to 4.5 mm) and the measurement position is varied (1.5 mm, 3.0 mm, 3.7 mm, 5.0 mm). Figure 7 The simulation results of TCR are shown when the width of slit 20 is varied (1.5 mm to 4.5 mm) and the measurement position is varied (1.5 mm, 3.0 mm, 3.7 mm, 5.0 mm).

[0048] In this embodiment, the set resistance value of the shunt resistor 1 is 100μΩ. When position 0mm is used as the reference position (centerline CL (reference)... Figure 1 When the electrode component 10 is at its center position, the resistance value and the TCR measurement position are equivalent to the distance from that reference position to the slit-side end 23.

[0049] Figure 6 The horizontal axis represents the location where the resistance value was measured. Figure 6 The vertical axis represents the resistance value [mΩ]. According to... Figure 6 It is clearly known that at the reference position of the electrode member 10, the larger the width of the slit 20, the greater the resistance value. The farther the measurement position is from the reference position of the electrode member 10, the smaller the resistance value. Therefore, the resistance value can be changed by changing the width of the slit 20. On the other hand, at a position closer to the slit end 23 than the position of the slit 20, although the resistance value decreases when the width of the slit 20 is increased, the change is not as significant.

[0050] Therefore, when the voltage detection wiring 25 is connected (joined) at a position closer to the reference position than the position of slit 20, the resistance characteristic changes depending on the connection position of the voltage detection wiring 25. On the other hand, when the voltage detection wiring 25 is connected (joined) at a position closer to the slit-side end 23 than the position of slit 20, the resistance characteristic hardly changes depending on the connection position of the voltage detection wiring 25. Thus, in order to suppress the deviation of the characteristics of the shunt resistor 1, it is preferable to connect the voltage detection wiring 25 at a position closer to the slit-side end 23 than the position of slit 20.

[0051] Although Figure 6 The simulation results are not shown, but the resistance value can vary depending on the location where the slit 20 is formed. That is, the resistance value increases when the slit 20 is formed at the reference position side, and decreases when the slit 20 is formed at the slit end 23 side.

[0052] Figure 7 The horizontal axis represents the measurement location of TCR. Figure 7 The vertical axis represents TCR [ppm / deg]. According to... Figure 7It is clearly known that at the reference position of electrode member 10, the larger the width of slit 20, the more positive the TCR tends to be. The further the measurement position is from the reference position of electrode member 10, the more negative the TCR tends to be. Therefore, by changing the width of slit 20, the TCR can be changed. On the other hand, at a position closer to the slit end 23 than the position of slit 20, when the width of slit 20 increases, the TCR becomes negative. Even if the measurement position changes, the TCR hardly changes.

[0053] Therefore, when the voltage detection wiring 25 is connected (joined) at a position closer to the reference position than the position of slit 20, the TCR characteristic changes depending on the connection position of the voltage detection wiring 25. On the other hand, when the voltage detection wiring 25 is connected (joined) at a position closer to the slit-side end 23 than the position of slit 20, the TCR characteristic hardly changes depending on the connection position of the voltage detection wiring 25. Thus, in order to suppress the deviation of the characteristics of the shunt resistor 1, it is preferable to connect the voltage detection wiring 25 at a position closer to the slit-side end 23 than the position of slit 20.

[0054] Depend on Figure 7 It is clearly understood that the TCR characteristics can be altered by changing the width of slit 20. In particular, as... Figure 7 As shown, the TCR characteristics caused by the change in the width of the slit 20 change significantly at the position of the slit end 23 closer to the reference position.

[0055] Although Figure 7 The simulation results are not shown, but the TCR can change depending on the location where the slit 20 is formed. That is, when the slit 20 is formed at the reference position side, the TCR is adjusted to the positive side, and when the slit 20 is formed at the slit end 23 side, the TCR is adjusted to the negative side.

[0056] The additional effects achieved by forming the slit 20 are described below. In the shunt resistor of Patent Document 1 (i.e., Japanese Unexamined Patent Application Publication No. 2018-170478), one method for changing the resistance value is to cut the resistor body. For example, by cutting the side of the resistor body, the cross-sectional area of ​​the resistor body (i.e., the current path) is reduced, and the resistance value is increased. However, in such a method, residual stress is sometimes generated in the resistor body. After being mounted on a circuit board, such residual stress may become a cause of resistance value variation. According to this embodiment, by forming the slit 20, the resistance value can be changed without cutting the resistor body 5. Therefore, resistance value variation caused by residual stress will not occur.

[0057] Figure 8 as well as Figure 9is a drawing showing another embodiment of the shunt resistor 1. The structure of the present embodiment not specifically mentioned is the same as that of the above-described embodiments, and thus the repeated description thereof is omitted. As shown in Figure 8 and Figure 9 , the electrode member 50 has a smaller size than the electrode member 10 of the above-described embodiments. More specifically, the electrode member 50 has a shorter length in the first direction than the electrode member 10.

[0058] The electrode member 50 has a contact site 50a that contacts the resistance body 5 on the whole thereof. By moving the electrode member 50 in the direction indicated by the white hollow arrow of Figure 8 , the contact site 50a of the electrode member 50 is connected to the resistance body 5 (see Figure 9 ). As shown in Figure 9 , the electrode member 50 has the same size as the resistance body 5 and the electrode 6.

[0059] The surface of the electrode member 50 (the surface of the electrode member 50 surrounded by the broken line in Figure 9 , in other words, the entire surface of the contact site 50a) is subjected to surface treatment (e.g., NiP plating, Ni plating, etc.) that enables joining. In order to enable solder mounting, the electrode 6 is subjected to surface treatment such as Sn plating or Ni plating.

[0060] As with the above-described embodiments, the slit 20 is an elongated hole extending in a direction perpendicular to the current direction. The contact site 50a of the electrode member 50 has a first surface 51 adjacent to the resistance body 5 and a second surface 52 on the opposite side of the first surface 51, and the slit 20 is a through-hole connected to these first surface 51 and second surface 52.

[0061] Figure 10 is a drawing showing one embodiment of a shunt resistor device 100 configured by mounting the shunt resistor shown in Figure 9 on the mounting pad pattern shown in Figure 3 . In the embodiment shown in Figure 10 , the shunt resistor device 100 has a voltage detection wiring 25 and a current wiring 55 connected to the electrode member 50.

[0062] As shown in Figure 10 , the voltage detection wiring 25 is disposed in a wiring region Al (a frame surrounded by a broken line) between the slit 20 and the slit-side end portion 53. The current wiring 55 is disposed in a wiring region A2 (a frame surrounded by a broken line) on the side opposite to the wiring region Al with the slit 20 interposed therebetween. This wiring region A2 is a region between the slit 20 and the opposite-side end portion 54.

[0063] In the embodiment shown in Figure 10 , the current wiring 55 is a plurality of (in Figure 10The number of the current wiring 55 is not limited to the present embodiment. The current wiring 55 is connected to the energization pattern 30 and the electrode member 50. A current path is formed by the energization pattern 30, the current wiring 55, the shunt resistor 1, and the energization pattern 31.

[0064] Figure 11 is a view showing a shunt resistor mounting to Figure 9 is a view showing another embodiment of a shunt resistor device 100 configured by mounting the shunt resistor shown in Figure 3 is a view showing another embodiment of a shunt resistor device 100 configured by mounting the shunt resistor shown in Figure 11 In the embodiment shown in Figure 10 and Figure 11 The shunt resistor device 100 can have at least one of the plurality of bonding wires and the clip-shaped terminal as the current wiring.

[0065] The above-described embodiments are described with the purpose of enabling a person having common knowledge in the technical field to which the present invention pertains to carry out the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Thus, the present invention is not limited to the described embodiments, but is to be interpreted as following the technical idea defined by the claims in the largest range.

[0066] Industrial applicability

[0067] The present invention can be used for a shunt resistor and a shunt resistor device.

[0068] Explanation of reference numerals

[0069] 1 shunt resistor

[0070] 5 resistor body

[0071] 5a first resistor body surface

[0072] 5b second resistor body surface

[0073] 6 electrode

[0074] 10 electrode member

[0075] 10a contact site

[0076] 11 main body portion

[0077] 14 terminal portion

[0078] 20 slit

[0079] 21 first surface

[0080] 22 second surface

[0081] 23 slit-side end portion

[0082] 24 opposite-side end portion

[0083] 25 voltage detection wiring

[0084] 26 voltage measurement device

[0085] 30 energization pattern

[0086] 31 energization pattern

[0087] 33 lead wire

[0088] 50 electrode member

[0089] 50a contact site

[0090] 51 first surface

[0091] 52 second surface

[0092] 53 slit-side end portion

[0093] 54 opposite-side end portion

[0094] 55 current wiring

[0095] 56 current wiring

Claims

1. A shunt resistance device, wherein, Comprise: a resistor body; an electrode member; an electrode; a voltage detection wiring connected to the electrode member; and a current wiring connected to the electrode member, the resistor body is plate-shaped having a thickness, has a first resistor body surface and a second resistor body surface, the electrode member has a contact site in contact with the resistor body, the contact site has a first face adjacent to the resistor body and a second face on the opposite side of the first face, by stacking the contact site, the resistor body, and the electrode in the thickness direction, the first face is connected to the first resistor body surface and the electrode is connected to the second resistor body surface, the electrode member is provided with a slit formed in the contact site, the slit is formed on the first resistor body surface to divide the area of the contact site into a first wiring area and a second wiring area, the voltage detection wiring is disposed in the first wiring area between the slit and the end of the electrode member, the current wiring is disposed in the second wiring area on the side opposite the first wiring area across the slit.

2. The shunt resistor device according to claim 1, wherein the slit is long in a direction perpendicular to the current direction.

3. The shunt resistor device according to claim 1 or 2, wherein the slit is a through-hole that penetrates the first face and the second face. ​

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