Shunt resistor and shunt resistor device

Abstract

The invention relates to a shunt resistor and a shunt resistor device. A shunt resistor (1) is provided with at least two laminated elements (50) each provided with a resistor (5) and attached to an electrode member (10). The electrode member (10) has at least two contact portions (10a) that are in contact with the at least two laminated elements (50).

Description

Technical Field

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

[0002] There is a shunt resistor that allows current to flow through a resistor and detects the magnitude of the current based on the voltage at both ends of the resistor (for example, see Patent Document 1). Such a shunt resistor includes a disc-shaped resistor and two electrodes formed on both sides of the resistor. One of the two electrodes is connected to a wiring (pad), and the other is connected to a bonding wire.

[0003] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2018-170478 Summary of the invention The electrodes connected to the bonding wires have a potential distribution. Therefore, due to the deviation of the connection position of the bonding wires, the detected resistance value and the temperature coefficient of resistance (TCR) of the shunt resistor may change. The temperature coefficient of resistance is an indicator that indicates the ratio of the change in resistance value due to temperature.

[0004] In the surface-mounted shunt resistor as described above, its status (whether it is faulty, the possibility of a fault, etc.) cannot be grasped. Therefore, even if the shunt resistor fails or has the possibility of a fault due to the application of a large current, etc., the fault of the shunt resistor cannot be predicted or detected.

[0005] Therefore, an object of the present invention is to provide a shunt resistor and a shunt resistor device whose state can be grasped.

[0006] In one embodiment, a shunt resistor is provided, comprising: an electrode member made of a conductive material; and at least two stacked elements mounted on the electrode member and having a resistor body. The electrode member has at least two contact portions that contact the at least two stacked elements.

[0007] In one embodiment, the electrode member includes an electrode member-side slit formed in the contact portion.

[0008] In one embodiment, the multilayer element includes a first electrode disposed on the opposite side of the electrode member with the resistor interposed therebetween.

[0009] In one embodiment, the multilayer element includes a second electrode disposed between the resistor and the electrode member.

[0010] In one embodiment, the stacked element includes a stacked element-side slit formed in the second electrode.

[0011] In one embodiment, the electrode member has a structure in which a temperature coefficient of resistance, which is an index indicating a ratio of a change in resistance value due to temperature, can be adjusted by the thickness of the electrode member.

[0012] In one embodiment, a shunt resistor device is provided, comprising: the shunt resistor; at least two voltage detection wirings connected to the at least two contact portions; and at least two voltage detection wirings that can be connected to an inner region of a current-carrying pattern for carrying the at least two stacked elements. The current-carrying pattern has a cutout formed in the inner region.

[0013] In one embodiment, the electrode member includes an electrode member side slit formed at the contact portion, and each of at least two voltage detection wirings connected to the at least two contact portions is arranged in a wiring region between the electrode member side slit and an end portion of the electrode member.

[0014] By disposing at least two stacked elements, the state of the shunt resistor can be understood. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a perspective view showing one embodiment of a shunt resistor for current detection.

[0016] Figure 2 yes Figure 1 A longitudinal cross-sectional view of a shunt resistor is shown.

[0017] Figure 3 It is a figure which shows the shunt resistor mounted on the mounting pad pattern.

[0018] Figure 4A It is a diagram showing another embodiment of the electrode component.

[0019] Figure 4B It is a diagram showing another embodiment of the electrode component.

[0020] Figure 5A It is a diagram showing another embodiment of the energization pattern.

[0021] Figure 5B It is a diagram showing another embodiment of the energization pattern.

[0022] Figure 6 2 is a diagram showing a current path formed by a current conduction pattern and a shunt resistor.

[0023] Figure 7 2 is a diagram showing a current path formed by a current conduction pattern and a shunt resistor.

[0024] Figure 8 2 is a diagram showing a current path formed by a current conduction pattern and a shunt resistor.

[0025] Fig. 9 2 is a diagram showing a current path formed by a current conduction pattern and a shunt resistor.

[0026] Fig.10 It is a diagram showing another embodiment of the shunt resistor.

[0027] Fig.11 It is a diagram showing another embodiment of the shunt resistor.

[0028] Fig.12 It is a diagram showing the slit formed in the second electrode. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0030] Figure 1 It is a perspective view showing one embodiment of a shunt resistor for current detection. Figure 2 yes Figure 1 The longitudinal section of the shunt resistor is shown in Figure 1. Figure 1 as well as Figure 2 As shown in FIG. 1 , the shunt resistor 1 includes an electrode member 10 made of a conductive material and at least two laminated elements 50 mounted on the electrode member 10. Figure 1 as well as Figure 2 In the illustrated embodiment, the shunt resistor 1 includes two stacked elements 50 , but may include three or more stacked elements 50 .

[0031] The laminated element 50 includes a plate-shaped (thin plate-shaped) resistor 5 having a predetermined thickness and width and a plate-shaped (thin plate-shaped) electrode (first electrode) 6A made of a conductive material. The electrode 6A is disposed on the opposite side of the electrode member 10 with the resistor 5 interposed therebetween.

[0032] An example of the material of the resistor 5 is a resistance alloy material such as a Cu-Mn-Ni alloy or a Ni-Cr alloy. An example of the material of the electrode 6A and the electrode member 10 is copper (Cu), which is a highly conductive metal.

[0033] The resistor 5 has a first resistor surface 5a and a second resistor surface 5b which is the surface on the opposite side of the first resistor surface 5a. The electrode component 10 is connected to the first resistor surface 5a, and the electrode 6A is connected to the second resistor surface 5b. That is, the electrode 6A, the resistor 5, and the electrode component 10 are stacked in this order in the thickness direction of the shunt resistor 1.

[0034] exist Figure 1as well as Figure 2 , the thickness direction of the shunt resistor 1 is parallel to the vertical direction. The first direction is the length direction of the shunt resistor 1, which is parallel to the current direction of the current passing through the shunt resistor 1. The second direction is the width direction of the shunt resistor 1, which is perpendicular to the first direction.

[0035] The electrode component 10 includes a contact portion 10a that contacts the stacked element 50 (the resistor 5 and the electrode 6A in this embodiment). The number of the contact portions 10a corresponds to the number of the stacked elements 50. In this embodiment, the shunt resistor 1 includes two stacked elements 50, so the electrode component 10 has two contact portions 10a.

[0036] The two stacked elements 50 are arranged symmetrically about the center line CL of the electrode component 10, and are arranged in series and separately with respect to the electrode component 10 in the first direction of the shunt resistor 1. The center line CL is an imaginary line segment extending parallel to the second direction of the shunt resistor 1 and bisecting the electrode component 10. The electrode component 10 has two end portions 23 in the first direction.

[0037] The electrode member 10 may be connected to the first resistor surface 5a of the resistor 5 by a conductive adhesive such as metal nanoparticles (silver paste using silver nanoparticles, copper paste using copper nanoparticles), welding such as pressure welding, or a connection method using solder. The electrode 6A may be connected to the second resistor surface 5b of the resistor 5 by the same connection method. The electrode 6A is subjected to a surface treatment such as Sn plating or Ni plating in order to enable solder mounting. The surface of the electrode 6A may not be plated.

[0038] The electrode component 10 has a structure that can adjust the temperature coefficient of resistance (TCR), which is an indicator of the ratio of the change in resistance value caused by temperature, by its thickness. More specifically, by adjusting the thickness of the electrode component 10, the accuracy of the TCR can be improved. For example, by reducing the thickness of the electrode component 10, the TCR can be reduced. In one embodiment, the electrode component 10 can have the same thickness as the thickness of the resistor 5, or can have a thickness thinner than the thickness of the resistor 5.

[0039] like Figure 1 as well as Figure 2As shown, the electrode component 10 has a slit (more specifically, an electrode component side slit) 20A formed at the contact portion 10a. In this way, by forming a slit at the contact portion 10a of the electrode component 10, the TCR can be adjusted. In the present embodiment, the slit 20A is a long hole extending in a direction perpendicular to the current direction (i.e., a direction parallel to the second direction), and penetrates from the surface of the electrode component 10 to the resistor 5. In one embodiment, the slit 20A may also be a depression formed on the surface of the electrode component 10. Each of the two end portions 23 is adjacent to the slit 20A formed at the contact portion 10a.

[0040] Figure 3 FIG. 1 is a diagram showing a shunt resistor mounted on a mounting pad pattern. Figure 3 As shown, the shunt resistor 1 has a wiring area AR ( Figure 3 The wiring area AR constitutes a part of the contact portion 10a, and one end of the voltage detection wiring 25 is connected to the wiring area AR during mounting. The other end of the voltage detection wiring 25 is connected to the connector 35.

[0041] Figure 4A as well as Figure 4B 2 is a diagram showing another embodiment of the electrode component. Figure 4A As shown in FIG. 1 , the electrode member 10 may also have a slit 20A formed in any one of the two contact portions 10a thereof. Figure 4B As shown, the electrode component 10 may not have the slit 20A. Figure 4B In the illustrated embodiment, the wiring region AR is formed in the region adjacent to both end portions 23 .

[0042] The voltage detection wiring 25 is a wiring (terminal) for detecting a potential difference between the electrode member 10 and the voltage detection wiring 33. The multilayer element 50, the electrode member 10, and the voltage detection wiring 25 connected to the electrode member 10 constitute the shunt resistor device 100.

[0043] The number of voltage detection wirings 25 corresponds to the number of stacked elements 50. Therefore, the shunt resistor device 100 has at least two voltage detection wirings 25 connected to at least two contact portions 10a. In one embodiment, the voltage detection wiring 25 may also be a bonding wire. In this case, a surface treatment (e.g., NiP plating, Ni plating, etc.) that enables bonding is applied to the wiring region AR of the electrode component 10 (more specifically, the contact portion 10a). There may also be no surface treatment of the electrode component 10.

[0044] like Figure 3As shown, the shunt resistor 1 is arranged on the mutually adjacent energizing patterns 30. Between the energizing patterns 30, a voltage detection wiring (lead wire) 33 is arranged. The lead wire 33 is a voltage detection terminal for detecting a potential difference generated between the electrode component 10. The energizing pattern 30 is formed on a circuit substrate such as a printed circuit board (not shown). The stacked element 50 (more specifically, the electrode 6A) is connected (joined) to the energizing pattern 30 by means such as solder.

[0045] The energizing pattern 30 includes a main body 30a, an inner region 30b disposed inside the main body 30a, and a cutout 30c formed in the inner region 30b and dividing the main body 30a and the inner region 30b. Figure 3 In the illustrated embodiment, the cutout 30c completely separates the main body 30a and the inner region 30b, and the laminated element 50 is connected to the inner region 30b of the energizing pattern 30 and a portion of the main body 30a. The lead wire 33 is connected to the inner region 30b of the energizing pattern 30.

[0046] Figure 5A as well as Figure 5B FIG. 2 is a diagram showing another embodiment of the energization pattern. Figure 5A In the illustrated embodiment, the cutout portion 30c has an arc shape, completely separating the main body portion 30a and the inner area 30b. Figure 5B In the embodiment shown, the cutout 30c has an L shape, and the main body 30a and the inner region 30b are connected. The lead wire 33 is not directly connected to the inner region 30b of the energizing pattern 30 but is separated. In addition, the electrode 6A when the laminated element 50 is connected to the energizing pattern is described in the figure.

[0047] Figures 6 to 9 3 is a diagram showing a current path formed by a current-carrying pattern and a shunt resistor. The voltage detection wiring 25 is connected to the electrode member 10 of the shunt resistor 1, and the lead wire 33 is connected to the current-carrying pattern 30, so as to form a current path flowing from the current-carrying pattern 30 in the thickness direction of the shunt resistor 1. In this embodiment, a voltage measuring device 26 is used to measure the potential difference between the voltage detection wiring 25 and the lead wire 33 (i.e., the potential difference in the resistor 5). By measuring this potential difference, the current value is calculated.

[0048] According to the present embodiment, the shunt resistor 1 is configured to include at least two stacked elements 50, and the potential difference in each stacked element 50 is measured. When an abnormality occurs in the shunt resistor 1, the resistance value of the abnormal stacked element 50 changes. According to the present embodiment, at least two stacked elements 50 are configured, and the resistance values ​​of a plurality of stacked elements 50 are compared, so that the state of the shunt resistor 1 can be grasped. Therefore, even if it is assumed that the shunt resistor 1 fails or there is a possibility of failure, the failure of the shunt resistor 1 can be predicted or detected.

[0049] exist Figure 6 In the illustrated embodiment, the shunt resistor 1 has the number of slits 20A corresponding to the number of the laminated elements 50, and the current-carrying pattern 30 has the number of cutout portions 30c corresponding to the number of the laminated elements 50. Figure 7 In the illustrated embodiment, the shunt resistor 1 has a single slit 20A, and the current-carrying pattern 30 has a single cutout portion 30c. Figure 8 In the illustrated embodiment, the shunt resistor 1 has the slits 20A whose number corresponds to the number of the laminated elements 50, but the current-carrying pattern 30 does not have the cutout portion 30c. Fig. 9 In the illustrated embodiment, the shunt resistor 1 does not have the slits 20A, and the current-carrying pattern 30 has the cutout portions 30 c whose number corresponds to the number of the laminated elements 50 .

[0050] Fig.10 1 is a diagram showing another embodiment of the shunt resistor. In the above embodiment, the shunt resistor 1 has at least one of the slit 20A and the cutout portion 30c. Fig.10 As shown, the shunt resistor 1 may not have the slit 20A and the cutout portion 30 c.

[0051] Fig.11 2 is a diagram showing another embodiment of a shunt resistor. Fig.11 As shown, the multilayer element 50 may include an electrode (second electrode) 6B disposed between the resistor 5 and the electrode member 10 .

[0052] Fig.12 FIG. 2 is a diagram showing a slit formed in the second electrode. Fig.12 As shown in FIG. 1 , the stacked element 50 may include a stacked element side slit 20B formed in the second electrode 6B. Fig.12In the embodiment shown, the electrode component side slit 20A and the stacked element side slit 20B penetrate in a manner to reach the resistor 5, but in one embodiment, the electrode component side slit 20A may be a depression formed on the surface of the electrode component 10. Alternatively, the electrode component side slit 20A may be a through hole that reaches the second electrode 6B. TCR is affected by the width, length, and formation position of the slit, so it is best to form it in a manner that can ensure good TCR. Fig.12 In the illustrated embodiment, the energizing pattern 30 does not have the cutout portion 30 c , but may have the cutout portion 30 c .

[0053] The above-mentioned embodiments are examples recorded for the purpose of enabling a person with common knowledge in the technical field to which the present invention belongs to implement the present invention. Those skilled in the art can certainly think of various variations of the above-mentioned embodiments, and the technical concept of the present invention can also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, and should be interpreted as complying with the widest scope of the technical concept defined by the claims.

[0054] Industrial Applicability The present invention can be used in a shunt resistor and a shunt resistor device.

[0055] (Explanation of symbols) 1: shunt resistor; 5: resistor; 5a: first resistor surface; 5b: second resistor surface; 6A: first electrode; 6B: second electrode; 10: electrode component; 10a: contact portion; 20A: slit (slit on the electrode component side); 20B: slit (slit on the stacked element side); 23: both ends; 25: voltage detection wiring; 26: voltage measuring device; 30: current-carrying pattern; 30a: main body; 30b: inner area; 30c: cutout; 33: voltage detection wiring (lead wire); 35: connector; 50: stacked element; 100: shunt resistor device; CL: center line; AR: wiring area.

Claims

1. A shunt resistor comprising: an electrode component made of a conductive material; and At least two stacked elements are mounted on the electrode member and have a resistor. The electrode member has at least two contact portions that are in contact with the at least two stacked elements.

2. The shunt resistor according to claim 1, wherein The electrode member includes an electrode member side slit formed at the contact portion.

3. The shunt resistor according to claim 1 or 2, wherein: The multilayer element includes a first electrode disposed on the opposite side of the electrode member with the resistor interposed therebetween.

4. The shunt resistor according to claim 3, wherein: The multilayer element includes a second electrode disposed between the resistor and the electrode member.

5. The shunt resistor according to claim 4, wherein: The stacked element includes a stacked element side slit formed in the second electrode.

6. The shunt resistor according to claim 1 or 2, wherein: The electrode member has a structure in which a temperature coefficient of resistance, which is an index indicating a ratio of a change in resistance value due to temperature, can be adjusted by a thickness thereof.

7. A shunt resistor device comprising: The shunt resistor according to claim 1 or 2; at least two voltage detection wirings connected to the at least two contact portions; and at least two voltage detection wirings connectable to an inner region of a current-carrying pattern for placing the at least two stacked elements, The energization pattern has a cutout portion formed in the inner region.

8. The shunt resistor device according to claim 7, wherein: The electrode member includes an electrode member side slit formed at the contact portion, Each of the at least two voltage detection wirings connected to the at least two contact sites is arranged in a wiring region between the electrode member side slit and an end portion of the electrode member.

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