KR20240043708A - Current detection device - Google Patents

Abstract

[Problem] To provide a current detection device that can suppress the decline in current detection accuracy.
[Solution] The current detection device 1 includes a resistor 20 through which a current flows along a first direction (X), a first conductor 21 connected to one end of the resistor in the first direction, and a resistor. A shunt resistor (2) having a second conductor (22) connected to the other end in the first direction, a substrate (3) having a current detection unit (31) that detects the current value flowing through the shunt resistor, and a first A first bus bar (4A) extending in a second direction (Y) perpendicular to the direction and fixed to the first conductor and the substrate to electrically connect the first conductor and the current detection unit, and in the second direction It is provided with a second bus bar 4B that extends and is fixed to the second conductor and the substrate and electrically connects the second conductor and the current detection unit.

Description

Current detection device {CURRENT DETECTION DEVICE}

The present invention relates to a current detection device.

Conventionally, there is a shunt resistor. Patent Document 1 discloses a shunt resistor that has, at least in part, a resistor with a resistance value set in advance, and detects the current value of the current flowing between the electrodes by bridging the space between two electrodes and detecting the voltage drop due to the resistor. It has been disclosed. The shunt resistor of Patent Document 1 is provided with a pair of connection parts that are fixed to each electrode through a conductive adhesive and electrically connected, and extending from one connection part to the other connection part, and bridge the connection parts. It is provided with a portion and a pair of bonding wires for detecting the voltage drop of the resistor, and the bonding wire is bonded to the crosslinking portion.

Japanese Patent Laid-Open No. 2016-053521

In a shunt resistor type current detection device, it is desirable to be able to suppress a decrease in detection accuracy. For example, when a board having a current detection unit and a shunt resistor are connected by a pair of conductors, if the connection angle of the conductor with respect to the shunt resistor is non-uniform, detection accuracy is likely to be reduced.

An object of the present invention is to provide a current detection device that can suppress a decrease in current detection accuracy.

The current detection device of the present invention includes a resistor through which a current flows in a first direction, a first conductor connected to one end of the resistor in the first direction, and a first conductor connected to the other end of the resistor in the first direction. a shunt resistor having a connected second conductor, a substrate having a current detection unit that detects a current value flowing through the shunt resistor, the first conductor and the substrate extending in a second direction perpendicular to the first direction; A first bus bar that is fixed to and electrically connects the first conductor and the current detection unit, extends in the second direction and is fixed to the second conductor and the substrate, and includes the second conductor and the It is characterized by having a second bus bar that electrically connects the current detection unit.

In the current detection device related to the present invention, a first bus bar extending in a second direction orthogonal to the direction of current flow is fixed to the first conductor and the substrate, and a second bus bar extending in the second direction is connected to the second conductor and the substrate. It is fixed to the substrate. According to the current detection device related to the present invention, the first bus bar and the second bus bar are rigidly fixed to the shunt resistor and the substrate, so that a decrease in current detection accuracy due to variation in the connection angle can be suppressed. indicates.

1 is a perspective view of a current detection device related to an embodiment.
Figure 2 is an exploded perspective view of a current detection device related to the embodiment.
Figure 3 is a perspective view of a first terminal block and a second terminal block related to the embodiment.
4 is a plan view of the first bus bar and the second bus bar according to the embodiment.
Figure 5 is a perspective view of a first bus bar and a second bus bar related to the embodiment.
Figure 6 is a top view of a current detection device related to the embodiment.
Fig. 7 is a cross-sectional view of a current detection device related to the embodiment.
Figure 8 is a perspective view of a current detection device related to the embodiment.
Fig. 9 is a top view of a current detection device related to the embodiment.

Below, a current detection device related to an embodiment of the present invention will be described in detail with reference to the drawings. Additionally, the present invention is not limited to this embodiment. In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

[Embodiment]

With reference to FIGS. 1 to 9, embodiments will be described. This embodiment relates to a current detection device. 1 is a perspective view of a current detection device related to the embodiment, FIG. 2 is an exploded perspective view of a current detection device related to the embodiment, FIG. 3 is a perspective view of a first terminal block and a second terminal block related to the embodiment, and FIG. 4 is a perspective view of a current detection device related to the embodiment. , a top view of the first bus bar and the second bus bar related to the embodiment, FIG. 5 is a perspective view of the first bus bar and the second bus bar related to the embodiment, and FIG. 6 is a top view of the current detection device related to the embodiment. , FIG. 7 is a cross-sectional view of the current detection device related to the embodiment, FIG. 8 is a perspective view of the current detection device related to the embodiment, and FIG. 9 is a top view of the current detection device related to the embodiment. In Figure 7, the section VII-VII of Figure 6 is shown.

1 and 2, the current detection device 1 of this embodiment includes a shunt resistor 2, a substrate 3, a first bus bar 4A, and a second bus bar 4B. have The current detection device 1 is, for example, disposed in a vehicle battery and detects the charging and discharging current of the battery. The current detection device 1 is a so-called shunt type current sensor. That is, the current detection device 1 passes a current through the shunt resistor 2 and measures the current value using Ohm's law from the voltage drop when the current is applied and the resistance value of the shunt resistor 2. The current detection device 1 may be configured as a monitoring unit that monitors the battery.

The shunt resistor 2 has a resistor 20, a first conductor 21, and a second conductor 22. The resistor 20 has a predetermined resistance value. The current detection device 1 calculates the current value based on the resistance value of the resistor 20. The shape of the illustrated resistor 20 is a rectangular plate shape. The first conductor 21 and the second conductor 22 are conductors formed of a metal with high conductivity such as copper. The illustrated shapes of the first conductor 21 and the second conductor 22 are flat. The first conductor 21 and the second conductor 22 are so-called bus bars and are rigid conductors. The first conductor 21 and the second conductor 22 are disposed on both sides of the resistor 20 with the resistor 20 sandwiched between them. The first conductor 21 and the second conductor 22 are physically and electrically connected to the resistor 20 .

One of the first conductor 21 and the second conductor 22 is connected to the negative electrode of the battery, for example. The other conductor of the first conductor 21 and the second conductor 22 is connected to a ground portion of, for example, a vehicle body. Based on the current value detected by the current detection device 1, the battery is monitored and controlled.

A current flows through the resistor 20 along the first direction (X). The first direction (X) is a direction in which the first conductor 21 and the second conductor 22 face each other. The first conductor 21 is connected to one end of the resistor 20 in the first direction (X), and the second conductor 22 is connected to one end of the resistor 20 in the first direction (X). It is connected to the other end.

In the following description, the width direction of the shunt resistor 2 is referred to as the “second direction (Y),” and the thickness direction of the shunt resistor 2 is referred to as the “third direction (Z).” The second direction (Y) is perpendicular to the first direction (X). The third direction (Z) is perpendicular to both the first direction (X) and the second direction (Y).

As shown in FIG. 2, the first conductor 21 has a first through hole 21a and a second through hole 21b. The second conductor 22 has a first through hole 22a and a second through hole 22b. The first through holes 21a and 22a are arranged adjacent to the resistor 20. The two first through holes 21a and 22a are arranged at positions symmetrical with respect to the resistor 20.

A screw 61 for fixing the first bus bar 4A to the first conductor 21 is inserted into the first through hole 21a. A nut 66 screwed to the screw 61 is fixed to the first conductor 21 . The nut 66 is arranged on the back surface of the first conductor 21 and is arranged coaxially with the first through hole 21a. A screw 62 for fixing the second bus bar 4B to the second conductor 22 is inserted into the first through hole 22a. A nut 67 screwed to the screw 62 is fixed to the second conductor 22 . The nut 67 is arranged on the back side of the second conductor 22 and is arranged coaxially with the first through hole 22a.

The second through holes 21b and 22b are located further away from the resistor 20 than the first through holes 21a and 22a. Fastening members such as bolts are inserted into the second through holes 21b and 22b. The first conductor 21 and the second conductor 22 are fastened to each other's bus bar, etc. by fastening members inserted into the second through holes 21b and 22b.

The board 3 is, for example, a printed circuit board (PCB). The shape of the illustrated substrate 3 is rectangular. The substrate 3 has a current detection unit 31. The current detection unit 31 is, for example, a current detection circuit. The board 3 may have a control circuit that monitors and controls the battery.

A first terminal block 7A and a second terminal block 7B are fixed to the board 3. The terminal blocks 7A and 7B are formed of a conductive metal plate such as copper. The first terminal block 7A and the second terminal block 7B are each electrically connected to the current detection unit 31. The first terminal block 7A and the second terminal block 7B are arranged at the end portion 3a of the board 3. The end portion 3a is an end adjacent to the shunt resistor 2 in the second direction (Y).

As shown in FIG. 3 , the first terminal block 7A and the second terminal block 7B have a connection portion 71 and two leg portions 72 . The connection portion 71 is a portion that is connected to the first bus bar 4A and the second bus bar 4B and supports the first bus bar 4A and the second bus bar 4B. The shape of the connection portion 71 is a flat plate. A female screw portion 71a is formed in the connecting portion 71. The female screw portion 71a has a cylindrical shape. A thread is formed on the inner peripheral surface of the female thread portion 71a.

The leg portion 72 is bent at a right angle with respect to the connecting portion 71. The leg portions 72 are disposed at both ends of the connecting portion 71 and support the connecting portion 71 . The leg portion 72 is in contact with the substrate 3 and is fixed to the substrate 3 with solder or the like. The connection part 71 is connected to the current detection part 31 via the leg part 72.

In this embodiment, bus bars 4 of the same shape are used as the first bus bar 4A and the second bus bar 4B. The bus bar 4 is formed of a conductive metal plate such as copper. As shown in FIGS. 4 and 5 , the bus bar 4 has a first terminal portion 41, a second terminal portion 42, and a low rigidity portion 43. The first terminal portion 41 is one end of the bus bar 4 and is a fixed portion fixed to the shunt resistor 2. The second terminal portion 42 is another end of the bus bar 4 and is a fixed portion fixed to the terminal blocks 7A and 7B. The low-rigidity portion 43 is a portion between the first terminal portion 41 and the second terminal portion 42.

The first terminal portion 41 has a through hole 41a into which the screws 61 and 62 can be inserted. The through hole 41a is disposed at the center of the first terminal portion 41 in the first direction (X). In other words, the through hole 41a is arranged in the central portion of the first terminal portion 41 in the width direction. The shape of the illustrated through hole 41a is an oval shape with a long axis in the second direction (Y). The bus bar 4 has a first regulating portion 44, as shown in FIG. 5 . The first regulating portion 44 is formed by bending the tip of the bus bar 4 on the side of the first terminal portion 41 . The first regulating portion 44 is perpendicular to the first terminal portion 41 . The first regulating portion 44 has a regulating surface 44a facing toward the second terminal portion 42 . The regulation surface 44a can regulate the direction in which the bus bar 4 extends, as will be described later.

The second terminal portion 42 has a through hole 42a into which the screws 63 and 64 shown in FIG. 2 can be inserted. The through hole 42a is disposed at the center of the second terminal portion 42 in the first direction (X). The shape of the illustrated through hole 42a is an oval shape with a long axis in the first direction (X). The bus bar 4 has a second regulating portion 46, as shown in FIG. 5 . The second regulating portion 46 is formed by bending the tip of the bus bar 4 on the side of the second terminal portion 42 . The second regulating portion 46 is perpendicular to the second terminal portion 42 .

The low-rigidity portion 43 is provided in the central portion of the bus bar 4 in the second direction (Y). The rigidity of the low-rigidity portion 43 is small compared to the rigidity of the first terminal portion 41 and the rigidity of the second terminal portion 42. The low-rigidity portion 43 is subjected to lightening processing to reduce the cross-sectional area in the cross-section perpendicular to the second direction Y. In the illustrated low-rigidity portion 43, the cross-sectional area is made small by having the through hole 43a. The through hole 43a penetrates the bus bar 4 in the plate thickness direction. The shape of the illustrated through hole 43a is rectangular extending along the second direction (Y).

The low-rigidity portion 43 has a bent portion 45. The bent portion 45 is formed by bending the bus bar 4 in two places. The bent portion 45 has a first bent portion 45a and a second bent portion 45b. In the longitudinal direction of the bus bar 4, the positions of the first bent portion 45a and the second bent portion 45b are different. The first bent portion 45a is located closer to the first terminal portion 41 than the second bent portion 45b.

The bus bar 4 is bent at a substantially right angle in the first bent portion 45a and the second bent portion 45b. A portion 45c extending in the third direction Z is provided between the first bent portion 45a and the second bent portion 45b. By providing the bent portion 45, a step in the third direction Z is formed between the first terminal portion 41 and the second terminal portion 42.

The low-rigidity portion 43 can absorb stress when an external force acts on the bus bar 4. For example, the low-rigidity portion 43 can absorb stress when a force in the third direction (Z) is applied to the bus bar 4 by having a small cross-sectional area. For example, the low-rigidity portion 43 can absorb stress when a force in the first direction (X) or the second direction (Y) is applied to the bus bar 4 by having the bent portion 45. . In this way, the stress caused by the bus bar 4 being rigidly fixed at both ends can be absorbed by the low-rigidity portion 43.

The first bus bar 4A and the second bus bar 4B of the present embodiment are fixed to the shunt resistor 2 and the substrate 3 so as to extend in the second direction Y, as shown in FIG. 6. do. The first bus bar 4A and the second bus bar 4B are fixed so that the center line CL of the bus bar 4 is perpendicular to the first direction X, for example, in plan view. It is preferable that the center line (CL) of the first bus bar (4A) and the center line (CL) of the second bus bar (4B) are parallel.

The first terminal portion 41 of the first bus bar 4A is fixed to the first conductor 21 of the shunt resistor 2 with a screw 61. The screw 61 is inserted into the through hole 41a of the first terminal portion 41 and the first through hole 21a of the first conductor 21 and screwed with the nut 66. That is, the first conductor 21 and the first bus bar 4A are fastened together by the screw 61 and the nut 66.

The second terminal portion 42 of the first bus bar 4A is fixed to the first terminal block 7A with a screw 63. The screw 63 is inserted into the through hole 42a of the second terminal portion 42 and screwed into the female thread portion 71a of the first terminal block 7A. That is, the second terminal portion 42 is fastened to the first terminal block 7A with the screw 63.

As shown in FIG. 7 , the first regulating portion 44 of the first bus bar 4A faces the side surface 21c of the first conductor 21. The side surface 21c of the first conductor 21 is perpendicular to the second direction Y and faces the side opposite to the side of the substrate 3. The regulation surface 44a of the first regulation part 44 faces the side surface 21c and is close to the side surface 21c. The first regulating portion 44 functions as a guide when the bus bar 4 is mounted on the shunt resistor 2. For example, the first regulating portion 44 positions the first bus bar 4A with respect to the first conductor 21 when the first bus bar 4A is placed on the first conductor 21. do. In more detail, the 1st regulation part 44 is guided by the side surface 21c so that the extension direction of 4 A of 1st bus bars may be made orthogonal to the 1st direction X.

Additionally, the first regulating portion 44 can regulate the rotation of the bus bar 4 with respect to the rotational torque when the screw 61 is screwed together. That is, when the first bus bar 4A attempts to rotate due to the rotational torque transmitted from the screw 61, the regulating surface 44a abuts the side surface 21c to prevent the rotation of the first bus bar 4A. regulate. In this way, the 1st regulation part 44 can regulate 4 A of 1st bus bars being inclined with respect to the 2nd direction Y.

The second regulating portion 46 of the first bus bar 4A faces the end surface 72a of the first terminal block 7A. The cross section 72a of the first terminal block 7A is perpendicular to the second direction Y and faces the side opposite to the side of the shunt resistor 2. The second regulating portion 46 has a regulating surface 46a facing the end surface 72a. The second regulating portion 46 functions as a guide when the bus bar 4 is placed on the first terminal block 7A. The 2nd regulation part 46 is guided by the end surface 72a so that the extension direction of 4 A of 1st bus bars may be made orthogonal to the 1st direction X.

Additionally, the second regulating portion 46 can regulate the rotation of the bus bar 4 with respect to the rotational torque when the screw 63 is screwed together. When the first bus bar 4A attempts to rotate due to the rotational torque transmitted from the screw 63, the regulating surface 46a abuts the end surface 72a to regulate the rotation of the first bus bar 4A. . In this way, the 2nd regulation part 46 can regulate 4 A of 1st bus bars being inclined with respect to the 2nd direction Y.

The first terminal portion 41 of the second bus bar 4B is fixed to the second conductor 22 of the shunt resistor 2 with a screw 62. The screw 62 is inserted into the through hole 41a of the first terminal portion 41 and the first through hole 22a of the second conductor 22 and screwed with the nut 67. The second terminal portion 42 of the second bus bar 4B is fixed to the second terminal block 7B with a screw 64. The screw 64 is inserted into the through hole 42a of the second terminal portion 42 and screw-engaged with the female thread portion 71a of the second terminal block 7B.

The 1st regulation part 44 of the 2nd bus bar 4B can regulate the 2nd bus bar 4B from being inclined with respect to the 2nd direction Y. As shown in FIG. 2, the second conductor 22 has a side surface 22c similar to the side surface 21c. The side surface 22c is perpendicular to the second direction Y and faces the side opposite to the side of the substrate 3. The 1st regulating part 44 of the 2nd bus bar 4B opposes the side surface 22c of the 2nd conductor 22, and extends the 2nd bus bar 4B in the 2nd direction Y.

The 2nd regulation part 46 of the 2nd bus bar 4B can regulate the 2nd bus bar 4B from being inclined with respect to the 2nd direction Y. The 2nd regulating part 46 of the 2nd bus bar 4B faces the end surface 72a of the 2nd terminal block 7B, and extends the 2nd bus bar 4B in the 2nd direction Y.

In the current detection device 1 of this embodiment, both the first bus bar 4A and the second bus bar 4B are extended in the second direction Y, and the first bus bar 4A and the second bus bar 4B are The bus bar (4B) can be rigidly fixed. By extending the first bus bar 4A and the second bus bar 4B in a direction perpendicular to the direction of current flow, variation in the voltage measurement distance is suppressed. As a comparative example, a configuration in which the shunt resistor 2 and the substrate 3 are connected by an electric wire is examined. In the comparative example, for example, a terminal mounted on a wire is screwed to the shunt resistor (2). In this case, it is not easy to extend the electric wire in the second direction (Y) with good precision. For example, the terminal is likely to rotate due to rotational torque when screwing. If the terminal rotates with respect to its normal position, the resistance value between the terminals includes the resistance components of the first conductor 21 and the second conductor 22. As a result, the accuracy of current measurement deteriorates.

In contrast, in the current detection device 1 of this embodiment, the extension directions of the first bus bar 4A and the second bus bar 4B are unlikely to become uneven. For example, if the shunt resistor 2 and the substrate 3 are fixed in advance, the first bus bar 4A and the second bus bar (4A) are The extension direction of 4B) is determined. Therefore, it is possible to extend the first bus bar 4A and the second bus bar 4B in the second direction (Y) with high precision.

In addition, the bus bar 4 of this embodiment is configured so that the bus bar 4 is easily orthogonal to the first direction (X). As described above, the through hole 41a of the first terminal portion 41 is oval along the longitudinal direction of the bus bar 4. On the other hand, the through hole 42a of the second terminal portion 42 is oval along the width direction of the bus bar 4.

Since the through hole 41a is an oblong circle along the second direction Y, when the first terminal portion 41 is fixed to the shunt resistor 2, the bus bar 4 is relative to the shunt resistor 2. It is difficult to turn. In addition, since the through hole 41a is an oblong circle along the second direction Y, when fixing the first terminal portion 41 to the shunt resistor 2, the regulating surface 44a of the first regulating portion 44 ) It is easy to keep the sides in contact with the sides (21c, 22c). Additionally, since the through hole 41a is an oblong circle along the second direction (Y), the position of the first terminal portion 41 in the first direction (X) is unlikely to be shifted. That is, the contact position of the first terminal portion 41 with respect to the first conductor 21 and the second conductor 22 is unlikely to be shifted. Therefore, the contact position of the first terminal portion 41 with respect to the first conductor 21 and the second conductor 22 can be brought close to the resistor 20, so that the first conductor 21 and the second conductor 22 It becomes possible to minimize the resistance component of .

Since the through hole 42a is an oblong circle along the first direction (X), it is possible to fix the second terminal portion 42 to the substrate 3 with the bus bar 4 extending in the second direction (Y). It's easy. It is preferable that the bus bar 4 of this embodiment is fixed to the shunt resistor 2 and then to the substrate 3.

Additionally, the current detection device 1 may have a case 10 shown in FIG. 8. Case 10 is molded, for example, from insulating synthetic resin. The case 10 has a storage chamber 11 that accommodates the substrate 3, and a holding portion 12 that holds the shunt resistor 2. The storage chamber 11 has a box shape, and the substrate 3 is accommodated and held therein. The shape of the accommodation chamber 11 in plan view is rectangular.

The holding portion 12 protrudes from the outer surface of the storage chamber 11 toward the second direction Y. The illustrated shape of the holding portion 12 is a rectangular plate shape. The side wall of the storage chamber 11 has a cutout 11a corresponding to the holding portion 12. The cutout 11a communicates the internal space of the accommodation chamber 11 and the external space on the side of the holding portion 12. The cutout 11a is formed so that the accommodation chamber 11 does not interfere with the first bus bar 4A and the second bus bar 4B. The shunt resistor 2 is fixed to the holding portion 12 by bolts 68 and 69. The holding portion 12 may have nuts that screw into the bolts 68 and 69.

As shown in Fig. 9, the holding portion 12 extends the first through hole 21a of the first conductor 21 in the second direction Y with respect to the female screw portion 71a of the first terminal block 7A. Oppose it. In other words, the case 10 is connected to the substrate 3 so that the virtual line 13A connecting the female screw portion 71a of the first terminal block 7A and the first through hole 21a is perpendicular to the first direction (X). ) and the shunt resistor (2). Additionally, the holding portion 12 opposes the first through hole 22a of the second conductor 22 in the second direction Y with respect to the female screw portion 71a of the second terminal block 7B. That is, the case 10 is positioned on the substrate 3 so that the virtual line 13B connecting the female screw portion 71a of the second terminal block 7B and the first through hole 22a is perpendicular to the first direction (X). and shunt resistor (2).

By holding the substrate 3 and the shunt resistor 2 in one case 10, it becomes easy to control the extension direction of the first bus bar 4A and the second bus bar 4B. That is, it becomes easy to connect the first bus bar 4A and the second bus bar 4B to the shunt resistor 2 at right angles to the direction of current flow.

As explained above, the current detection device 1 of this embodiment has a shunt resistor 2, a substrate 3, a first bus bar 4A, and a second bus bar 4B. The shunt resistor 2 has a resistor 20 through which a current flows along the first direction (X), a first conductor 21, and a second conductor 22. The first conductor 21 is connected to one end of the resistor 20 in the first direction (X). The second conductor 22 is connected to the other end of the resistor 20 in the first direction (X). The substrate 3 has a current detection unit 31 that detects the current value flowing through the shunt resistor 2.

The first bus bar 4A extends in the second direction (Y) perpendicular to the first direction (X) and is fixed to the first conductor 21 and the substrate 3, so that the first conductor 21 ) and the current detection unit 31 are electrically connected. The second bus bar 4B extends in the second direction Y and is fixed to the second conductor 22 and the substrate 3 to electrically connect the second conductor 22 and the current detection unit 31. Connect to . In the current detection device 1 of this embodiment, the first bus bar 4A and the second bus bar 4B are fixed to the shunt resistor 2 and the substrate 3. Therefore, it is easy to make the extension directions of the first bus bar 4A and the second bus bar 4B orthogonal to the first direction (X). Additionally, it is easy to extend the first bus bar 4A and the second bus bar 4B in parallel. Therefore, the current detection device 1 of this embodiment can suppress a decrease in current detection accuracy.

The first conductor 21 and the second conductor 22 of this embodiment have side surfaces 21c and 22c perpendicular to the second direction Y. The first bus bar 4A and the second bus bar 4B have a first regulating portion 44 formed by bending an end portion on the side of the shunt resistor 2. The 1st regulation part 44 opposes the side surfaces 21c and 22c in the 2nd direction Y, and the 1st bus bar 4A and the 2nd bus bar 4B are in the 2nd direction Y. Regulates the slope. Therefore, the current detection device 1 of this embodiment can suppress a decrease in current detection accuracy.

The first bus bar 4A and the second bus bar 4B of this embodiment have a low-rigidity portion 43 between the fixing portion for the shunt resistor 2 and the fixing portion for the substrate 3. . In the low-rigidity portion 43, through-holes 43a are formed in the first bus bar 4A and the second bus bar 4B. The low-rigidity portion 43 can absorb stress occurring in the first bus bar 4A and the second bus bar 4B. Additionally, the low-rigidity portion 43 may have a cutout instead of the through hole 43a or in addition to the through hole 43a.

The low-rigidity portion 43 of this embodiment has a bent portion 45. The bent portion 45 is formed by bending the first bus bar 4A and the second bus bar 4B at two different locations in the longitudinal direction. The bent portion 45 includes a portion 45c extending in a third direction (Z) perpendicular to either the first direction (X) or the second direction (Y). Additionally, the low-rigidity portion 43 may be bent in three or more places.

The current detection device 1 may have a case 10, a first terminal block 7A, and a second terminal block 7B. The case 10 has a storage chamber 11 that accommodates the substrate 3 and a holding portion 12 that holds the shunt resistor 2. The first terminal block 7A and the second terminal block 7B are fixed to the substrate 3. In this case, the first bus bar 4A is fixed to the first terminal block 7A and connected to the current detection unit 31 via the first terminal block 7A. The second bus bar 4B is fixed to the second terminal block 7B and is connected to the current detection unit 31 via the second terminal block 7B. By arranging the shunt resistor 2 and the substrate 3 in the case 10, it becomes easy to secure an appropriate relative position between the shunt resistor 2 and the substrate 3.

It is configured as a monitoring unit equipped with a case 10, a shunt resistor 2, a board 3, a first bus bar 4A, and a second bus bar 4B. At the stage where the monitoring unit is configured, it can be checked whether the resistance value between the bus bars (4A, 4B) is the desired value. By equipping the battery with a monitoring unit that has been confirmed to have the desired resistance value, the accuracy of current detection is unlikely to deteriorate.

Additionally, the means for fixing the shunt resistor 2 to the case 10 is not limited to the bolts 68 and 69. For example, the holding portion 12 of the case 10 may have a holding structure that holds the shunt resistor 2. The retaining structure may have a concave portion that accommodates the shunt resistance 2. In this case, the shunt resistor 2 may be press-fitted into the concave portion of the holding portion 12.

The contents disclosed in the above embodiments can be implemented by combining them appropriately.

1: Current detection device
2: shunt resistor, 3: substrate, 4A: first busbar, 4B: second busbar
7A: 1st terminal block, 7B: 2nd terminal block
20: resistor, 21: first conductor, 21a: first through hole, 21b: second through hole
21c: side
22: second conductor, 22a: first through hole, 22b: second through hole, 22c: side
31: Current detection unit
41: first terminal portion, 42: second terminal portion, 43: low rigidity portion, 44: first regulating portion
45: bending portion, 46: second regulating portion
61, 62, 63, 64: screw, 66, 67: nut, 68, 69: bolt
71: connection part, 71a: female thread part, 72: leg part, 72a: cross section
X: 1st direction, Y: 2nd direction, Z: 3rd direction

Claims (5)

A shunt having a resistor through which current flows in a first direction, a first conductor connected to one end of the resistor in the first direction, and a second conductor connected to the other end of the resistor in the first direction. resistance,
A substrate having a current detection unit that detects a current value flowing through the shunt resistor;
a first bus bar extending in a second direction perpendicular to the first direction and fixed to the first conductor and the substrate to electrically connect the first conductor and the current detection unit;
A current detection device comprising a second bus bar extending in the second direction, fixed to the second conductor and the substrate, and electrically connecting the second conductor and the current detection unit. According to claim 1,
The first conductor and the second conductor have side surfaces perpendicular to the second direction,
The first bus bar and the second bus bar have a first regulating portion formed by bending an end on the side of the shunt resistor,
The current detection device wherein the first regulating portion faces the side surface in the second direction and regulates the first bus bar and the second bus bar to be inclined with respect to the second direction. According to claim 1,
The first bus bar and the second bus bar have a low rigidity portion between a fixing portion for the shunt resistor and a fixing portion for the substrate,
In the low-rigidity portion, a through hole or cutout is formed in the first bus bar and the second bus bar. According to claim 3,
The low-rigidity portion has a bending portion,
The bent portion is formed by bending the first bus bar and the second bus bar at a plurality of locations, and includes a portion extending in a third direction orthogonal to either the first direction or the second direction. Current detection device. The method according to any one of claims 1 to 4,
a case having a receiving chamber for accommodating the substrate and a holding portion for holding the shunt resistor;
Provided with a conductive first terminal block and a second terminal block fixed to the substrate,
The first bus bar is fixed to the first terminal block and connected to the current detection unit through the first terminal block,
A current detection device wherein the second bus bar is fixed to the second terminal block and connected to the current detection unit via the second terminal block.