JP2013096881A - Current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current detector capable of reducing stress applied to a fixed portion on the side of a battery.SOLUTION: A current detector 100 includes: a first fixed portion 112 fixed to the side of a battery 200; a second fixed portion 114 fixed with a harness 300 thereto; a bus bar 110 as a resistor inserted between the first fixed portion 112 and the second fixed portion 114; a circuit board 120 mounted with a current detection circuit for detecting current flowing in the bus bar 110 on the basis of a potential difference at two portions in an energization direction of the bus bar 110 thereon; and a case 130 for storing the bus bar 110 and the circuit board 120 therein. A current energization portion 110A of the bus bar 110 is formed by folding back a conductor at two portions between the first fixed portion 112 connected to one end and the second fixed portion 114 connected to the other end.

Description

  The present invention relates to a current detection device that is mounted on a passenger car, a truck, or the like and detects a charge / discharge current of a battery.

  Conventionally, a first fixing portion that is fixed to the battery-side wiring and is electrically connected, a second fixing portion that is fixed and is electrically connected to the harness, and the first and second A U-shaped resistor inserted between the first and second fixed portions, a case disposed between the first and second fixed portions, the resistor and the circuit board being housed, and disposed on the battery side surface; There is known a current detection device that detects a current flowing through a harness through a terminal of a battery (see, for example, Patent Document 1).

JP 2011-69807 A (page 4-8, FIG. 1-7)

  By the way, in the structure disclosed in Patent Document 1 described above, since the first fixed portion and the second fixed portion are arranged apart on both sides of the resistor and the circuit board, the space between these fixed portions is When the harness is fastened and fixed to the second fixing portion, the stress applied to the first fixing portion on the battery side increases, and there is a problem that looseness and deformation are likely to occur. Further, not only when the harness is fastened but also when the vehicle is traveling, a large stress is applied to the first fixing portion on the battery side along with the vibration of the harness, so that the possibility of loosening and deformation is further increased.

  This invention is created in view of such a point, and the objective is to provide the electric current detection apparatus which can reduce the stress added to the fixing | fixed part by the side of a battery.

  In order to solve the above-described problem, the current detection device of the present invention is a current detection device that detects a current flowing through a harness through a terminal of a battery, and is fixed to the wiring on the battery side to be electrically connected. A first fixing portion, a second fixing portion in which a harness is fixed and electrical connection is made, a resistor inserted between the first and second fixing portions, and a current-carrying direction of the resistor A circuit board on which a current detection circuit for detecting a current flowing through the resistor based on a potential difference at two locations along the resistor is mounted, and a case in which the resistor and the circuit board are stored. It is formed by folding the conductor in two places between the first fixed portion connected to the second fixed portion and the second fixed portion connected to the other end. Specifically, the resistor described above includes a first conductor connected to the first fixed portion, a second conductor formed by folding back an end portion of the first conductor, and a second conductor. The third conductor is formed by folding the end of the second conductor, and the end is connected to the second fixing portion.

  By folding back the resistor at two locations, the length of the resistor is secured to increase the accuracy of current detection, and the distance between the two fixed portions provided at both ends of the resistor is shortened to secure the harness. Further, it is possible to reduce the stress applied to the battery-side fixing portion during traveling.

  Further, it is desirable that the above-described two foldings are performed by combining the first folding that is folded in the direction in which the extending direction is deviated and the second folding that is folded in the direction in which the extending directions are overlapped. Accordingly, the distance between the two fixing portions can be shortened, and the two fixing portions can be provided at appropriate positions in consideration of workability.

  Moreover, it is desirable that the first fixing portion, the second fixing portion, and the current conducting portion described above are disposed on the upper surface of the battery. Moreover, it is desirable that the circuit board described above is disposed on the side surface of the battery. Thereby, the thickness of the site | part which protrudes in the side surface direction of a battery can be made thin. In addition, since the heavy resistance portion made of a metal material can be brought close to the battery-side fixing portion, it is possible to reduce the stress applied to the fixing portion by the weight of the product.

  Moreover, it is desirable that the above-described resistance portion is formed by folding a linear plate-like member at two locations. By using a linear plate-shaped member, the yield when manufacturing the resistance portion can be improved, and the manufacturing cost can be reduced.

  Moreover, it is desirable to arrange the first fixing portion and the second fixing portion described above on the same plane. Thereby, the distance between two fixing | fixed parts can be shortened, and the stress added to the fixing | fixed part by the side of a battery can further be reduced.

  Moreover, it is desirable that the above-described resistance portion is insert-molded with a resin material forming the case. Since the resistor portion is folded back at two places to form a complicated shape, the adhesion between the resistor portion and the resin when the resistor portion is insert-molded can be improved. Thereby, an inexpensive resin material can be used, and the manufacturing cost can be reduced.

It is a top view of the electric current detection apparatus of one Embodiment. It is a side view of an electric current detection apparatus. It is a side view of an electric current detection apparatus. It is an enlarged view of a bus bar. It is a top view of an electric current energization part. It is a top view of a leader line part. It is a perspective view of an electric current energization part. It is a top view which shows the positional relationship of an electric current detection apparatus and a battery. It is a side view which shows the positional relationship of an electric current detection apparatus and a battery. It is a top view of an electric current detection apparatus. It is a side view of an electric current detection apparatus. It is a side view of an electric current detection apparatus. It is a figure which shows the example of a connection of the specific example of the circuit of an electric current detection apparatus, a battery, etc.

  Hereinafter, a current detection device according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings.

  FIG. 1 is a plan view of a current detection device according to an embodiment. FIG. 2 is a side view of the current detection device, and shows a shape viewed from below in FIG. FIG. 3 is a side view of the current detection device, and shows a shape viewed from the right in FIG.

  The current detection device 100 of the present embodiment flows through the bus bar 110 based on a bus bar 110 as a resistor (shunt resistance) formed using a conductive material and two potential differences along the energizing direction of the bus bar 110. A circuit board 120 on which a current detection circuit for detecting current is mounted, a case 130 for housing the bus bar 110 and the circuit board 120, and a plurality of connector terminals that are electrically connected to the circuit board 120 are provided therein. An exposed connector 140 and a lid 150 that covers the opening of the recess of the case 130 in which the circuit board 120 is housed are provided.

  The bus bar 110 has a shape that is folded twice in the case 130, and has one end fixed to the wiring on the battery 200 side to form a first fixing portion 112 that is electrically connected. The other end portion forms the second fixing portion 114 to which the harness is fixed and electrical connection is performed. The first fixing portion 112 and the second fixing portion 114 are provided on the same plane, that is, so that the heights of the upper surfaces thereof are at the same position.

  4 is an enlarged view of the bus bar 110, and only the bus bar 110 is extracted from the current detection device 100 shown in FIG. The bus bar 110 includes a current conducting part 110A serving as a path for a current flowing through the first fixing part 112 and the second fixing part 114, and a lead line part 110B for extracting a potential difference from two locations of the current conducting part 110A. FIG. 5 is a plan view of the current conducting unit 110A. FIG. 6 is a plan view of the lead wire portion 110B. FIG. 7 is a partial perspective view of the current conducting unit 110A. In the present embodiment, the first fixed portion 112, the second fixed portion 114, and the current conducting portion 110 </ b> A are disposed on the upper surface of the battery 200, and the circuit board 120 is disposed on the side surface of the battery 200. The current conducting unit 110A and the circuit board 120 are connected to each other through the lead wire part 110B.

  110 A of current conducting parts are formed by folding a linear plate-like member in a direction perpendicular to the upper surface of the battery 200. Specifically, the current conducting part 110A includes a first conductor 110A1 connected to the first fixed part 112, and a second conductor 110A2 formed by folding back the end of the first conductor 110A1. The third conductor 110A3 is formed by folding the end portion of the second conductor 110A2, and the end portion opposite to the folded portion is connected to the second fixing portion 114. Desirably, the current conducting unit 110A first bends the first conductor 110A1 and the second conductor 110A2 in a direction in which the extending directions deviate from each other (in the example illustrated in FIG. 4, the respective longitudinal directions are vertical). And the second conductor 110A2 and the third conductor 110A3 are folded in the direction in which the extending directions overlap each other (the respective longitudinal directions are parallel to each other).

  The lead wire portion 110B is used to connect the current conducting portion 110A to the circuit board 120. The current conducting part 110A and the lead line part 110B described above are formed of different members (FIGS. 5 and 6), and the lead line part 110B is welded to the current conducting part 110A to be mechanically fixed and electrically connected. Is done. Further, as shown in FIG. 6, the lead wire portion 110B includes two lead conductors 110B1 and 110B2 that are connected and integrated with each other via a connecting portion 110B3. The lead wire portion 110B is maintained in an integrated state in which the two lead conductors 110B1 and 110B2 are connected via the connecting portion 110B3 until the lead wire portion 110B is welded to the current conducting portion 110A. And after welding, connection part 110B3 is cut | disconnected.

  The end conductor of one lead conductor 110B1 is welded to the inner surface of the first conductor 110A1 at one corner a of the first conductor 110A1 (the back side (lower side) of the first conductor 110A1 in FIG. 4). Surface). Further, the end of the other lead conductor 110B2 is welded at the inner surface of the third conductor 110A3 at one corner b of the third conductor 110A3 (the front side (upper side) of the third conductor 110A3 in FIG. 4). The surface).

  Each of the two lead conductors 110B1 and 110B2 is drawn from the corners a and b toward the side surface of the battery 200 on which the circuit board 120 is disposed, and then drawn in a direction parallel to the side surface. Furthermore, it is drawn around in the same direction as the part drawn out from the corners a and b. In this case, by changing the length of the portion drawn in a direction parallel to the side surface of the battery 200, the position of the portion in which the circuit board 120 is accommodated in the case 130 is shifted along the side surface direction of the battery 200. Is possible. Moreover, even if such a change is made, it is not necessary to change the positions of the corners a and b where the two lead conductors 110B1 and 110B2 are welded. It does not affect the relationship with the current value, and it is not necessary to change the current detection circuit.

  FIG. 8 is a plan view showing the positional relationship between the current detection device 100 and the battery 200, and shows a state in which the current detection device 100 is mounted on the battery 200 and the terminal 302 of the harness 300 is further attached. FIG. 9 is a side view showing the positional relationship between the current detection device 100 and the battery 200. As shown in these drawings, the negative terminal 202 of the battery 200 is attached with the current detecting device 100 and a mounting bracket 210 that also serves as a wiring between the negative terminal 202 and the first fixing portion 112. Yes. A bolt 211 projects upward from the end of the mounting bracket 210. In the present embodiment, the bolt 211 of the mounting bracket 210 is inserted into the through hole 112A (FIG. 1) provided in the first fixing portion 112 and the fixing portion 112 is tightened with the nut 212, whereby the mounting bracket 210 is attached to the mounting bracket 210. The first fixing part 112 is fixed.

  The second fixing portion 114 is provided with a through hole, and a bolt 115 is inserted into the through hole. On the other hand, a terminal 302 having a through hole is provided at an end portion of the harness 300 electrically connected to the second fixing portion 114, and the second fixing portion 114 is provided in the through hole of the terminal 302. The terminal 302 is fixed to the second fixing portion 114 by inserting the bolt 115 and tightening the terminal 302 with the nut 303.

  In the present embodiment, the case 130 is formed of a resin material having good insulation and thermal conductivity, for example, PPS (polyphenylene sulfide) resin, and is externally provided as the first fixing portion 112 or the second fixing portion 114. The entire bus bar 110 (or most of the bus bar 110) excluding the exposed portion is insert-molded with this resin material.

  By the way, as described above, in the bus bar 110 having a complicated shape folded back at two locations, a potential difference between the corner portions a and b is detected from the two corner portions a and b that are spaced apart from each other. Two lead conductors 110B1 and 110B2 for extending to the circuit board 120 side. The leading end of one lead conductor 110B1 is used as a current detection terminal c1. The other lead conductor 110B2 has a bifurcated tip, and one end is used as a sensing ground terminal c2 and the other end is used as a circuit ground terminal c3. The reason why the circuit ground terminal c3 is provided separately from the sensing ground terminal c2 is to suppress fluctuations in the potential of the sensing ground terminal c2 as much as possible during the operation of various circuits mounted on the circuit board 120. If the fluctuation is small, the circuit ground terminal c3 may be omitted. Three terminals (current detection terminal c1, sensing ground terminal c2, and circuit ground terminal c3) extending from the bus bar 110 are soldered in a state of being passed through through holes provided in the circuit board 120. The current detection circuit in the circuit board 120 is electrically connected.

  In general, the bus bar 110 through which a large current flows from the battery 200 has a large heat capacity. Therefore, when soldering is performed using the tip of the lead wire portion 110B drawn from the current conducting portion 110A of the bus bar 110 as a terminal, heating is insufficient. In such a case, soldering may be insufficient and soldering failure may occur. In this embodiment, the device which can confirm a soldering state visually is made so that the presence or absence of generation | occurrence | production of such a soldering defect can be checked easily.

  FIG. 10 is a plan view of the current detection device 100 and shows a state in which the lid 150 is removed. FIG. 11 is a side view of the current detection device, and shows a shape viewed from below in FIG. FIG. 12 is a side view of the current detection device, and shows a shape viewed from the right direction in FIG. 10.

  As shown in FIG. 10, three terminals (current detection terminal c <b> 1, sensing ground terminal c <b> 2, circuit extension) extend from the bus bar 110 on the bottom surface of the recess 132 of the case 130 provided for housing the circuit board 120. The ground terminal c3) protrudes. These terminals are passed through through holes provided in the circuit board 120 and then soldered from the non-insertion side (terminal end side). Further, the positions of these terminals c1, c2, and c3 are set at the end of the circuit board 120 (in the vicinity of the upper end of the circuit board 120 in FIG. 12).

  Further, the engaging portion (opening end portion of the recessed portion 132) 134 between the opening of the recessed portion 132 and the lid 150 is set on the same plane and is not parallel to the surface of the circuit board 120. . That is, as shown in FIG. 11, by tilting the engaging portion 134, a part of the circuit board 120 is exposed to the outside from a portion where the side surface of the recess 132 is lowered when the lid 150 is removed. It has become. And in this exposed part, these soldering parts in the front and back of the circuit board 120 are in the side direction of the circuit board 120 and the terminals c1, c2, c3 are visually observed from the side where the soldering part is arranged. It is possible to easily check the state of.

  As shown in FIG. 12, the engaging portion 134 is formed with a groove portion 134 </ b> A over the entire circumference in a direction perpendicular to the surface of the engaging portion 134. A convex portion (not shown) is formed at a corresponding position of the lid 150, and the lid 150 is attached to the concave portion 132 so that the groove portion 134A and the convex portion correspond to each other. The lid 150 is attached by inclining the current detection device 100 so that the surface of the engaging portion 134 on the concave portion 132 side is horizontal. At that time, an adhesive is applied to the inside of the groove 134A, and the lid 150 is fixed to the case 130 by adhesion. In addition, a modified example is conceivable in which a convex portion is provided on the engagement portion 134 on the case 130 side and a groove portion is provided on the lid 150 side, or adhesion is performed without using the groove portion or the convex portion.

  FIG. 13 is a diagram illustrating a connection example between a specific example of the circuit of the current detection device 100 and the battery 200 or the like. As shown in FIG. 13, the circuit board 120 of the current detection device 100 includes a differential amplifier 10 connected to both ends of a shunt resistor 100 ′ as a resistor formed by a part of the bus bar 110, and a plus of the battery 200. Differential amplifier 12, temperature detection unit 20, current detection processing unit 30, voltage detection processing unit 32, temperature detection processing unit 34, battery state detection unit 36, charge control unit 40, communication input / output Sections (communication I / O) 50 and 52, a CAN interface (CAN I / F) 60 that transmits and receives data according to the CAN protocol, and a LIN interface (LIN I / F) 62 that transmits and receives data according to the LIN protocol And is equipped. One differential amplifier 10 amplifies the voltage across the shunt resistor 100 ′, and the current detection processing unit 30 detects the current flowing through the shunt resistor 100 ′ based on the output voltage of the differential amplifier 10. The differential amplifier 10 and the current detection processing unit 30 constitute a current detection circuit. The other differential amplifier 12 converts the voltage across the battery 200 (battery voltage) to an appropriate level, and the voltage detection processing unit 32 detects the battery voltage based on the output voltage of the differential amplifier 12. The temperature detection unit 20 is configured by a voltage dividing circuit including a resistor and a thermistor. The resistance value of the thermistor changes according to the temperature, and the divided voltage of the voltage dividing circuit changes. The temperature detection processing unit 34 detects the temperature of the current detection device 100 (the temperature of the battery 200) based on the output voltage (divided voltage) of the temperature detection unit 20. The battery state detection unit 36 takes in the detection values of the current detection processing unit 30, the voltage detection processing unit 32, and the temperature detection processing unit 34, and generates a battery state signal. The current detection processing unit 30, voltage detection processing unit 32, temperature detection processing unit 34, and battery state detection unit 36 constitute a state detection sensor 38. The charge control unit 40 controls the power generation state of the vehicle generator (G) 80 based on the battery state signal generated by the battery state detection unit 36. This power generation control is performed by sending an instruction to the power generation control device 82 mounted on the vehicle generator 80 via the communication input / output unit 52 and the LIN interface 62. The battery status signal generated by the battery status detection unit 36 is sent to the vehicle system 70 via the communication input / output unit 50 and the CAN interface 60. The vehicle system 70 performs integrated control on the engine and various electric loads based on the received battery state signal and the like.

  As described above, in the current detection device 100 of the present embodiment, the bus bar 110 as the resistor is folded back at two locations, thereby ensuring the length of the current supply unit 110A and improving the accuracy of current detection, and the current supply unit. The distance between the two fixing portions 112 and 114 provided at both ends of 110A can be shortened to reduce the stress applied to the fixing portion 112 on the battery 200 side when the harness 300 is fastened and running.

  In addition, the folding of the two portions of the current conducting portion 110A is a combination of the first folding 110C1 that is folded in the direction in which the extending direction is shifted and the second folded 110C2 that is folded in the direction in which the extending directions are overlapped. The distance between the two fixing portions 112 and 114 can be further shortened, and the two fixing portions 112 and 114 can be provided at appropriate positions in consideration of workability.

  Further, the first fixing portion 112, the second fixing portion 114, and the current conducting portion 110 </ b> A are disposed on the upper surface of the battery 200, and the circuit board 120 is disposed on the side surface of the battery 200, thereby projecting in the lateral direction of the battery 200. The thickness of the part to be performed can be reduced. Further, since the heavy bus bar 110 (current conducting portion 110A) formed of a metal material can be brought close to the fixing portion 112 on the battery 200 side, the stress applied to the fixing portion 112 due to the weight of the product is reduced. Is possible.

  Further, by forming the current conducting part 110A by folding the linear plate-like member at two locations, the yield when manufacturing the current conducting part 110A can be improved, and the manufacturing cost can be reduced. Become. Further, by arranging the first fixing portion 112 and the second fixing portion 114 on the same plane, the distance between the two fixing portions 112 and 114 can be shortened, and the fixing portion 112 on the battery 200 side can be reduced. The applied stress can be further reduced.

In addition, the bus bar 110 is insert-molded with a resin material forming the case 130, and the current-carrying part 110A is folded back at two locations to form a complicated shape. Therefore, the current-carrying part 110A and the resin when the bus-bar 110 is insert-molded The adhesion between the two can be improved. Thereby, an inexpensive resin material can be used, and the manufacturing cost can be reduced. Note that the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the present invention. Is possible. In the above-described embodiment, the case where the bus bar 110 and the resistor are integrated has been described, but a resistor separate from the bus bar 110 may be used.

  Further, in the above-described embodiment, the current detection device 100 is attached to the negative terminal 202 of the battery 200 via the mounting bracket 210. However, the first detection portion 112 of the current detection device 100 may be modified to be long. The current detection device 100 may be directly attached to the negative terminal 202.

  In the above-described embodiment, the current-carrying portion 110A of the bus bar 110 is formed by folding the straight plate-like member twice. However, a non-linear plate-like member is used, or folding is performed twice. The angle may be changed.

  As described above, according to the present invention, the bus bar 110 as a resistor is folded back at two locations, thereby ensuring the length of the current conducting portion 110A and improving the accuracy of current detection, and at both ends of the current conducting portion 110A. The distance between the two fixing portions 112 and 114 provided on the battery 200 can be shortened to reduce the stress applied to the fixing portion 112 on the battery 200 side when the harness 300 is fastened and traveled.

DESCRIPTION OF SYMBOLS 100 Current detection apparatus 110 Bus bar 110A Current energizing part 110A1 1st conductor 110A2 2nd conductor 110A3 3rd conductor 110B Lead-out line part 110B1, 110B2 Lead-out conductor 110B3 Connection part 112 1st fixing | fixed part 112A Through-hole 114 2nd Fixed part 120 Circuit board 130 Case 132 Recess 134 Engagement part 140 Connector 150 Lid 200 Battery 300 Harness

Claims (8)

A current detection device for detecting a current flowing through a harness through a terminal of a battery,
A first fixing portion fixed to the wiring on the battery side and electrically connected;
A second fixing portion where the harness is fixed and electrical connection is made;
A resistor inserted between the first and second fixing portions;
A circuit board on which a current detection circuit for detecting a current flowing through the resistor based on a potential difference between two locations along the energization direction of the resistor is mounted;
A case in which the resistor and the circuit board are stored;
The resistor is formed by folding a conductor at two locations between the first fixed portion connected to one end and the second fixed portion connected to the other end. A characteristic current detection device. In claim 1,
The resistor includes a first conductor connected to the first fixed portion, a second conductor formed by folding back an end portion of the first conductor, and an end portion of the second conductor. And a third conductor having an end connected to the second fixed portion. In claim 1 or 2,
The current detection device according to claim 1, wherein the folding of the two locations is performed by combining a first folding that is bent in a direction in which the extending direction is deviated and a second folding that is bent in a direction in which the extending directions are overlapped. In any one of Claims 1-3,
The current detection device, wherein the first fixing unit, the second fixing unit, and the current conducting unit are arranged on an upper surface of the battery. In claim 4,
The circuit board is disposed on a side surface of the battery. In any one of Claims 1-5,
The current detection device, wherein the resistance portion is formed by folding a linear plate-like member at the two locations. In any one of Claims 1-6,
The current detecting device, wherein the first fixing portion and the second fixing portion are arranged on the same plane. In any one of Claims 1-7,
The current detection device, wherein the resistance portion is insert-molded with a resin material forming the case.

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