Temperature detection device and current detection device using same

Abstract

This temperature detection device, which is used in a current detection device, comprises: a flat plate-shaped conductive member (50) in which a current flows in an extension direction, with one direction as the extension direction; temperature detection units (71, 72) that output a temperature detection signal corresponding to the temperature of the conductive member; and a connection unit (60) that connects the conductive member to the temperature detection unit. The conductive member includes a resistance part (51), a first conductive part (52) that has a lower electrical resistance than the resistance part and is provided on one side of the resistance part in the extension direction, and a second conductive part (53) that has a lower electrical resistance than the resistance part and is provided on the other side of the resistance part in the extension direction. The connection part includes a first connection part (61) connected to the first conductive part and a second connection part (62) connected to the second conductive part. The temperature detection unit is disposed at a position where the distance from the second connection unit to the temperature detection unit is smaller than the distance from the first connection unit to the temperature detection unit. The second conductive part has a larger thermal resistance than the first conductive part.

Description

Temperature Detection Device and Current Detection Device Using the Same Cross - Reference to Related Applications

[0001] This application is based on Japanese Patent Application No. 2024 - 195922 filed on November 8, 2024, and Japanese Patent Application No. 2025 - 120586 filed on July 17, 2025, the contents of which are incorporated herein by reference.

[0002] This disclosure relates to a temperature detection device.

[0003] Conventionally, a battery sensor including a resistance unit, a current measurement device that detects a voltage drop of the resistance unit, and a temperature sensor that detects the temperature of a measurement path connecting the resistance unit and the current measurement device has been known (see, for example, Patent Document 1). The resistance unit is formed of a measurement resistor, a first connection portion connected to one side of the measurement resistor, and a second connection portion connected to the other side of the measurement resistor. Then, the battery sensor detects the voltage drop of the measurement resistor, and based on Ohm's law using the detected voltage drop and the electrical resistance of the measurement resistor, calculates the current passing through the battery sensor. However, the electrical resistance of the measurement resistor changes with temperature. Therefore, the battery sensor detects the temperature of the measurement path connecting the measurement resistor and the current measurement device by the temperature sensor, calculates the electrical resistance of the measurement resistor using the detected temperature, and calculates the current passing through the battery sensor.

[0004] In the battery sensor described in Patent Document 1, where the temperature sensor is disposed in the measurement path, this measurement path is configured to include contact pins protruding from each of the first connection portion and the second connection portion. And the temperature sensor is connected to the measurement resistor via the first connection portion, the contact pin protruding from the first connection portion, the contact pin protruding from the second connection portion, and the second connection portion.

[0005] European Patent Application Publication No. 3671151

[0006] According to the inventors' diligent research, when a temperature sensor is connected to a measuring resistor via a contact pin, as in the battery sensor described in Patent Document 1, there is a risk that the temperature difference between the temperature detected by the temperature sensor and the actual temperature of the measuring resistor will be large. Therefore, if the electrical resistance of the measuring resistor is calculated based on the detected temperature, which has a large temperature difference from the actual temperature, the electrical resistance of the measuring resistor cannot be calculated accurately. Accordingly, in a current measuring device that measures current, such as the battery sensor described in Patent Document 1, it is necessary to accurately determine the temperature of the conductive material through which the current flows.

[0007] In view of the above points, the purpose of this disclosure is to provide a temperature detection device capable of improving temperature detection accuracy.

[0008] According to one aspect of this disclosure, a temperature detection device used in a current detection device comprises a conductive member shaped like a flat plate through which current flows in the direction of extension, with one direction being the extension direction; a temperature detection unit that outputs a temperature detection signal corresponding to the temperature of the conductive member; and a connection unit that connects the conductive member to the temperature detection unit. The conductive member includes a resistive portion, a first conductive portion having less electrical resistance than the resistive portion and provided on one side of the resistive portion in the direction of extension, and a second conductive portion having less electrical resistance than the resistive portion and provided on the other side of the resistive portion in the direction of extension. The connection unit includes a first connection unit connected to the first conductive portion and a second connection unit connected to the second conductive portion. The temperature detection unit is positioned such that the distance from the second connection unit to the temperature detection unit is smaller than the distance from the first connection unit to the temperature detection unit. The second conductive portion has greater thermal resistance than the first conductive portion.

[0009] According to this, when current flows through the conductive material, the part of the resistive section that reaches the highest temperature is the part on the second conductive section side of the center in the extension direction. Furthermore, the temperature difference between the highest temperature in the resistive section and the temperature of the second conductive section is smaller than the temperature difference between the highest temperature in the resistive section and the temperature of the first conductive section.

[0010] Therefore, the temperature difference between the detected temperature and the temperature of the resistance when the temperature detection unit detects the temperature of the resistance via the second connection part connected to the second conductive part can be suppressed. Consequently, the temperature detection unit can accurately detect the temperature of the resistance.

[0011] From another perspective, the current detection device comprises the aforementioned temperature detection device and a current detection unit that outputs a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value of the conductive member and the voltage applied to the conductive member.

[0012] According to this, the current detection unit can accurately detect the current value of the current flowing through the conductive member based on the temperature of the resistor accurately detected by the temperature detection unit.

[0013] This is a schematic diagram of the battery management system according to the first embodiment. This is a perspective view of the current detection device according to the first embodiment. This is an exploded perspective view of the current detection device according to the first embodiment. This is a view of the conductive busbar according to the first embodiment from one side in the third direction. This is a cross-sectional view of the conductive busbar according to the first embodiment. This is a view of the sensor housing according to the first embodiment from one side in the third direction. This is a view of the sensor housing according to the first embodiment from the other side in the third direction. This is a view of the wiring board according to the first embodiment from one side in the third direction. This is a view of the wiring board according to the first embodiment from the other side in the third direction. This is a block diagram of the first sensing unit and the second sensing unit according to the first embodiment. This is a view of the first shield according to the first embodiment from one side in the third direction. This is a view of the first shield according to the first embodiment from the other side in the third direction. This is a view of the second shield according to the first embodiment from one side in the third direction. This is an explanatory diagram for explaining the temperature change when current flows through the comparative conductive busbar. This is an explanatory diagram for explaining the temperature change when current flows through the conductive busbar according to the first embodiment. This is a diagram showing a conductive busbar according to a first modification of the first embodiment. This is a diagram showing a method for connecting a wiring board and a conductive busbar according to a second modification of the first embodiment. This is a diagram showing a conductive busbar according to a second embodiment. This is a diagram showing a conductive busbar according to a third embodiment. This is a diagram showing a conductive busbar according to a fourth embodiment. This is a diagram showing a conductive busbar according to a first modification of the fourth embodiment. This is a diagram showing a conductive busbar according to a second modification of the fourth embodiment. This is an explanatory diagram for explaining the temperature change when current flows through the conductive busbar according to a second modification of the fourth embodiment. This is a diagram showing a conductive busbar according to a fifth embodiment. This is a diagram showing a conductive busbar according to a sixth embodiment. This is a diagram showing a conductive busbar according to a seventh embodiment. This is a view of the conductive busbar according to an eighth embodiment from one side in the third direction. This is a view of the conductive busbar according to an eighth embodiment from one side in the first direction. This is a cross-sectional view of a conductive busbar according to a ninth embodiment. This is an explanatory diagram for explaining the part to which a conductive busbar applied to a battery management system according to a tenth embodiment is connected. This is a cross-sectional view of the conductive busbar and the part to which the conductive busbar is connected according to a tenth embodiment.This is an explanatory diagram of a bolt for fastening a conductive busbar applied to a battery management system according to the 11th embodiment. This is a cross-sectional view of a portion to which a conductive busbar applied to a battery management system according to a modified example of the 11th embodiment is connected. This is an explanatory diagram for explaining a portion to which a conductive busbar applied to a battery management system according to the 12th embodiment is connected. This is a schematic configuration diagram of a battery management system according to the 12th embodiment. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to the 13th embodiment. This is a perspective view of a conductive busbar according to the 13th embodiment. This is a perspective view of a busbar without a recess. This is a diagram showing the experimental results of investigating the variation in electrical resistance due to misalignment of the mounting position of the busbar without a recess. This is a diagram showing the experimental results of investigating the variation in electrical resistance due to misalignment of the mounting position of the conductive busbar according to the 13th embodiment. This is a diagram illustrating the current flowing from the busbar without a recess to the first connection pin. This is a diagram illustrating the current flowing from the conductive busbar to the first connection pin according to the 13th embodiment. This is a perspective view of a conductive busbar according to a modified example of the 13th embodiment. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to a modified example of the 13th embodiment. This is a perspective view of a conductive busbar according to the 14th embodiment. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to the 14th embodiment. This is an explanatory diagram for explaining the manufacturing method of the conductive busbar according to the 14th embodiment. This is a cross-sectional view showing the manufacturing process of the conductive busbar, following Figure 48. This is a perspective view of a conductive busbar according to a modified example of the 14th embodiment. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to a modified example of the 14th embodiment. This is a plan view for explaining a conductive busbar according to the 15th embodiment. This is a plan view for explaining a conductive busbar according to a modified example of the 15th embodiment. This is a plan view of a conductive busbar according to the 16th embodiment. This is a plan view of a conductive busbar according to a modified example of the 16th embodiment. This is a plan view of a conductive busbar according to the 17th embodiment. This is a plan view of a conductive busbar according to a modified example of the 17th embodiment. This is an explanatory diagram for explaining a current detection device according to the 18th embodiment. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to the 18th embodiment. This is an explanatory diagram for explaining a first washer included in the current detection device according to the 18th embodiment.This is an explanatory diagram for illustrating a current detection device according to a modified example of the 18th embodiment. This is a cross-sectional view of a conductive busbar and the part to which the conductive busbar is connected according to a modified example of the 18th embodiment. This is an explanatory diagram for illustrating a second washer provided in the current detection device according to a modified example of the 18th embodiment. This is an explanatory diagram for illustrating a current detection device according to the 19th embodiment. This is a cross-sectional view of a conductive busbar and the part to which the conductive busbar is connected according to the 19th embodiment. This is an explanatory diagram for illustrating a current detection device according to a modified example of the 19th embodiment. This is a cross-sectional view of a conductive busbar and the part to which the conductive busbar is connected according to a modified example of the 19th embodiment. This is a cross-sectional view of a conductive busbar and the part to which the conductive busbar is connected according to a modified example of the 201st embodiment. This is a plan view for illustrating a current detection device according to the 22nd embodiment. This is a plan view for illustrating a current detection device according to a modified example of the 22nd embodiment. This is a plan view for illustrating a current detection device according to the 23rd embodiment. This is a plan view illustrating a current detection device according to a modified example of the 23rd embodiment. This is a plan view illustrating a current detection device according to the 24th embodiment. This is a plan view illustrating a current detection device according to a modified example of the 24th embodiment. This is a view of a wiring board according to another embodiment, seen from one side in the third direction. This is a cross-sectional view of a conductive busbar and a portion to which the conductive busbar is connected according to another embodiment. This is a perspective view of a conductive busbar according to another embodiment.

[0014] Embodiments of this disclosure will be described below with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the prior embodiments will be denoted by the same reference numerals, and their descriptions may be omitted. Also, if only a part of a component is described in an embodiment, the components described in the prior embodiments can be applied to the other parts of that component. The following embodiments can be partially combined with each other, even if not explicitly stated, as long as it does not impede the combination.

[0015] (First Embodiment) This embodiment will be described with reference to Figures 1 to 16. The temperature detection device of this embodiment is used, for example, in the current detection device 1 of the battery management system VMS shown in Figure 1, which manages the battery VT of a vehicle. The battery management system VMS is a circuit system having a conductive path forming section that forms a conductive path through which current flows, and is a temperature management system that manages the temperature of the battery VT, which is the object to be managed, in order to use the battery VT safely and efficiently. Current flows through the conductive path of the battery management system VMS as the battery VT discharges. The current detection device 1 then detects the current flowing through the conductive path. First, the battery management system VMS will be described with reference to Figure 1. As shown in Figure 1, the battery management system VMS includes a battery VT, a system main relay SMR, a battery ECU 200, and a current detection device 1.

[0016] The battery VT can be a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride secondary battery. As shown in Figure 1, the battery VT is connected to an inverter INV mounted on the vehicle and supplies power to the inverter INV to drive the vehicle. The inverter INV is connected to a motor generator (not shown) and outputs an alternating current for the motor generator to rotate, and also converts the power generated by the motor generator into a direct current to charge the battery VT. The supply of power from the battery VT to the inverter INV is controlled by a system main relay SMR.

[0017] The system main relay SMR consists of three relays RL. These three relays RL are located between the battery VT and the inverter INV. Each of the three relays RL controls the electrical connection between the battery VT and the inverter INV by switching on or off. The system main relay SMR prevents inrush current from flowing into the inverter INV by controlling the timing of switching these three relays RL on. Note that these relays RL that make up the system main relay SMR are heat-generating devices that generate heat through their switching operation. A fuse HS and a limiting resistor RS are placed between the battery VT and the system main relay SMR to prevent overcurrent from flowing.

[0018] The battery ECU 200 monitors the State of Charge (SOC) of the battery VT based on the current detected by the current detection device 1 (described later) and controls the charging of the battery VT. As shown in Figure 1, the battery ECU 200 is connected to the EV-ECU 300. The battery ECU 200 and EV-ECU 300 are computers mainly consisting of a control circuit equipped with a CPU (not shown), recording media such as ROM and RAM, input / output interfaces, and buses connecting them. ECU stands for electronic control unit. SOC stands for state of charge. CPU, ROM, and RAM are abbreviations for Central Processing Unit, Read Only Memory, and Random Access Memory, respectively. The ROM and RAM of the battery ECU 200 and EV-ECU 300 are composed of non-transitional physical storage media.

[0019] The EV-ECU 300 controls the amount of power supplied to the motor generator (not shown) and the amount of regenerative power from the drive motor based on control signals obtained from the battery ECU 200. The EV-ECU 300 is connected to the battery ECU 200.

[0020] The current detection device 1 is connected between the battery VT and the inverter INV. Specifically, the current detection device 1 is electrically connected to the inverter INV via the energized busbar BU. The current detection device 1 detects and calculates the current flowing from the battery VT to the inverter INV, and also detects and calculates the current flowing from the inverter INV to the battery VT.

[0021] Next, the current detection device 1 will be described. As shown in Figures 2 to 5, the current detection device 1 includes a sensor housing 10, a wiring board 20, a first shield 30, a second shield 40, a conductive busbar 50, and a connection part 60. In addition, the temperature detection device of this embodiment is composed of some of these components that make up the current detection device 1. In the current detection device 1, one side of the conductive busbar 50 is connected to the battery VT, and the other side is connected to the energized busbar BU. Therefore, the current detection device 1 detects the DC current flowing from the battery VT to the inverter INV through the conductive busbar 50. The conductive busbar 50 corresponds to a conductive material.

[0022] First, the components of the current detection device 1 will be described in detail individually. In the following, the three directions that are orthogonal to each other will be referred to as the first direction D1, the second direction D2, and the third direction D3. The second direction D2 corresponds to the extension direction of the conductive busbar 50. The first direction D1 is the direction orthogonal to the second direction D2 and corresponds to the width direction of the conductive busbar 50. The third direction D3 is the direction orthogonal to both the first direction D1 and the second direction D2 and corresponds to the thickness direction of the conductive busbar 50.

[0023] <Sensor Housing> The sensor housing 10 is made of an insulating resin material. As shown in Figures 2, 3, 6, and 7, the sensor housing 10 is provided with a wiring board 20, a first shield 30, and a second shield 40. In addition, a portion of the conductive busbar 50 is insert-molded into the sensor housing 10. Specifically, the wiring board 20 is fixed to the sensor housing 10 in a manner that faces the portion of the conductive busbar 50 that is insert-molded into the sensor housing 10. The first shield 30 and the second shield 40 are fixed to the sensor housing 10 in a manner that they are spaced apart from each other. The portions of the wiring board 20 and the conductive busbar 50 that face each other are positioned between the first shield 30 and the second shield 40.

[0024] The conductive busbar 50, the wiring board 20, the first shield 30, and the second shield 40 are arranged spaced apart in the third direction D3. Furthermore, connection terminals 14 that are electrically and mechanically connected to the wiring board 20 are insert-molded into the sensor housing 10. These connection terminals 14 are electrically connected to the battery ECU 200 via a wire harness or the like.

[0025] As shown in Figures 6 and 7, the sensor housing 10 has a base portion 11, an insulating portion 12, and a connector portion 13. The base portion 11 is a rectangular parallelepiped with the first direction D1 as its extension direction. On one side of the base portion 11 in the third direction D3, there are multiple substrate support pins 111 that support the wiring board 20 and multiple first shield support pins 112 that support the first shield 30. On the other side of the base portion 11 in the third direction D3, there are multiple second shield support pins 113 that support the second shield 40.

[0026] The substrate support pins 111, the first shield support pins 112, and the second shield support pins 113 are formed to extend in the third direction D3. The wiring board 20 is housed in the sensor housing 10 such that the busbar-facing surfaces 22 (described later) contact the tips of the substrate support pins 111. The wiring board 20 and the substrate support pins 111 are bonded together, for example, by an adhesive. The first shield 30 is mounted on the sensor housing 10 such that the first back surface 32 (described later) contacts the tips of the first shield support pins 112. The first shield 30 and the first shield support pins 112 are bonded together, for example, by an adhesive. The second shield 40 is mounted on the sensor housing 10 such that the second back surface 42 (described later) contacts the tips of the second shield support pins 113. The second shield 40 and the second shield support pins 113 are bonded together, for example, by an adhesive. As a result, the base portion 11 is provided with a first shield 30 on one side in the third direction D3, and a second shield 40 on the other side in the third direction D3.

[0027] As shown in Figure 6, the insulating portions 12 are formed on one and the other side of the base portion 11 in the second direction D2. These two insulating portions 12 extend in the second direction D2 away from the base portion 11. The two insulating portions 12 are aligned in the second direction D2 through the base portion 11. The conductive busbar 50 is partially covered by the base portion 11 and each of the two insulating portions 12.

[0028] As shown in Figures 2 and 3, the connector portion 13 is formed on the other side of the base portion 11 in the third direction D3. The connector portion 13 is cylindrical and extends in the third direction D3 away from the base portion 11. Part of the connection terminal 14 is housed inside the connector portion 13. The connector portion 13 is connected to a connector such as a wire harness.

[0029] The connection terminal 14 extends in the third direction D3. One side of the connection terminal 14 in the third direction D3 is exposed from the base 11 and surrounded by the base 11, while the other side is surrounded by the connector portion 13. In the first direction D1, the connection terminal 14 is separated from the portion of the conductive busbar 50 covered by the base 11.

[0030] As described above, a DC current flows through the conductive busbar 50 to input and output the battery VT. A less current than the DC current flowing through the conductive busbar 50 flows through the connection terminal 14 between the wiring board 20 and the battery ECU 200. If the creepage distance between the conductive busbar 50 and the connection terminal 14 is small, there is a risk that the conductive busbar 50 and the connection terminal 14 will conduct electricity and short circuit.

[0031] To prevent such malfunctions, ribs 121 are formed on each of the insulating portions 12 provided on one side and the other side of the base portion 11 in the second direction D2. The ribs 121 protrude from one side of the insulating portion 12 in the third direction D3. The ribs 121 extend in the first direction D1. The length of the ribs 121 in the first direction D1 is longer than the length of the conductive busbar 50 in the first direction D1.

[0032] The ribs 121 provided on one side of the base 11 in the second direction D2 and the ribs 121 provided on the other side of the base 11 in the second direction D2 are located between the portion of the conductive busbar 50 exposed from the sensor housing 10 and the portion of the connection terminal 14 exposed from the base 11. These ribs 121 increase the creepage distance between the conductive busbar 50 and the connection terminal 14 on the surface of the sensor housing 10. This suppresses short circuits between the conductive busbar 50 and the connection terminal 14.

[0033] Furthermore, the ribs 121 provided on one side of the base 11 in the second direction D2 and the ribs 121 provided on the other side of the base 11 in the second direction D2 are located between the portion of the conductive busbar 50 exposed from the sensor housing 10 and the first shield 30 and the second shield 40. This also suppresses short circuits between the conductive busbar 50 and the first shield 30 and the second shield 40. By extending the creepage distance with the ribs 121, the length of the insulating portion 12 in the second direction D2 can be shortened. This suppresses an increase in the size of the current detection device 1.

[0034] <Wiring board> As shown in Figures 8 and 9, the wiring board 20 is formed in a flat plate shape. Specifically, the wiring board 20 is formed in a flattened shape with a thin thickness in the third direction D3. The wiring board 20 is formed by laminating multiple insulating resin layers and conductive metal layers in the third direction D3. The wiring board 20 has a shield-facing surface 21 on one side in the third direction D3 that faces the first shield 30, and a busbar-facing surface 22 on the other side in the third direction D3 that faces the conductive busbar 50.

[0035] As shown in Figure 8, a first sensing unit 23, a second sensing unit 24, and a third sensing unit 25 are mounted on the shield-facing surface 21 of the wiring board 20. The first sensing unit 23, the second sensing unit 24, and the third sensing unit 25 mounted on the wiring board 20 are housed in the sensor housing 10. As shown in Figure 9, a first thermistor 71 and a second thermistor 72 are mounted on the busbar-facing surface 22 of the wiring board 20. The first magnetoelectric conversion unit 231a of the first sensing unit 23 and the second magnetoelectric conversion unit 241a of the second sensing unit 24 are mounted in the parts facing the conductive busbar 50.

[0036] As shown in Figure 10, the first sensing unit 23 has a first ASIC 231 and a first filter 232. The second sensing unit 24 has a second ASIC 241 and a second filter 242. The first ASIC 231 and the first filter 232 are electrically connected to each other via a wiring pattern on the wiring board 20. The second ASIC 241 and the second filter 242 are electrically connected to each other via a wiring pattern on the wiring board 20. The wiring pattern connecting the first ASIC 231 and the first filter 232 is electrically connected to a connection terminal 14. The wiring pattern connecting the second ASIC 241 and the second filter 242 is electrically connected to a connection terminal 14. ASIC stands for application specific integrated circuit.

[0037] The first sensing unit 23, the second sensing unit 24, and the third sensing unit 25 may be mounted on the busbar-facing surface 22. Also, the first thermistor 71 and the second thermistor 72 may be mounted on either or both of the shield-facing surfaces 21.

[0038] By the way, the first sensing unit 23 and the second sensing unit 24 are formed with the same configuration as each other. For this reason, only the first sensing unit 23 will be described in detail below, and the detailed description of the second sensing unit 24 will be omitted. <ASIC> The first ASIC 231 has a first magnetoelectric conversion unit 231a and a first processing circuit 231b. The first magnetoelectric conversion unit 231a and the first processing circuit 231b are electrically connected. The first magnetoelectric conversion unit 231a has a plurality of magnetoresistive elements whose resistance value changes according to the magnetic field that passes through it, i.e., the transmitted magnetic field. The resistance value of these magnetoresistive elements changes according to the transmitted magnetic field along the shield-facing surface 21. That is, the resistance value of the magnetoresistive elements changes according to the component along the first direction D1 and the component along the second direction D2 of the transmitted magnetic field. In contrast, the resistance value of the magnetoresistive elements does not change due to the transmitted magnetic field along the third direction D3. Therefore, even if external noise along the third direction D3 passes through the magnetoresistive element, its resistance value does not change as a result.

[0039] The magnetoresistive element has a pin layer with a fixed magnetization direction, a free layer whose magnetization direction changes according to the transmitted magnetic field, and a non-magnetic intermediate layer provided between the two. The magnetoresistive element may be a giant magnetoresistive element with a non-conductive intermediate layer, or a tunnel magnetoresistive element with a conductive intermediate layer. Alternatively, the magnetoresistive element may be an anisotropic magnetoresistive element. Furthermore, the first magnetoelectric conversion unit 231a may have a Hall element instead of a magnetoresistive element.

[0040] The resistance of a magnetoresistive element changes depending on the angle between the magnetization directions of the pinned layer and the free layer. The magnetization direction of the pinned layer is along the shield-facing surface 21. The magnetization direction of the free layer is determined by the transmitted magnetic field along the shield-facing surface 21. The resistance of the magnetoresistive element is smallest when the magnetization directions of the free layer and the fixed layer are parallel and in the same direction, and largest when the magnetization directions of the free layer and the fixed layer are parallel but in opposite directions.

[0041] The first magnetoelectric conversion unit 231a has a first one-sided element 231c and a first other-sided element 231d as the magnetoresistive elements described above. The magnetization directions of the pin layers of the first one-sided element 231c and the first other-sided element 231d are 90° different. Therefore, when the resistance values ​​of the first one-sided element 231c and the first other-sided element 231d change, the increase or decrease in their respective values ​​is inverse. That is, when the resistance value of one of the first one-sided element 231c and the first other-sided element 231d decreases, the resistance value of the other increases by an amount equal to the decrease in the resistance value of the first.

[0042] The first magnetoelectric conversion unit 231a has two first one-side elements 231c and two first other-side elements 231d. The first one-side elements 231c and the first other-side elements 231d are connected in series in this order from the power supply potential toward the reference potential to form one half-bridge circuit. Furthermore, the first other-side elements 231d and the first one-side elements 231c are connected in series in this order from the power supply potential toward the reference potential to form another half-bridge circuit. Thus, in these two half-bridge circuits, the order of the first one-side elements 231c and the first other-side elements 231d is reversed. Therefore, the midpoint potential of the two half-bridge circuits is configured such that if the potential of one decreases, the potential of the other increases. In the first magnetoelectric conversion unit 231a, these two half-bridge circuits are combined to form a full-bridge circuit.

[0043] The first magnetoelectric conversion unit 231a includes, in addition to the first one-sided element 231c and the first other-sided element 231d that constitute the above-described full-bridge circuit, a first differential amplifier 231e, a first feedback coil 231f, and a first shunt resistor 231h. The first differential amplifier 231e has the midpoint potentials of two half-bridge circuits input to its inverting input terminal and non-inverting input terminal. Also, from the output terminal of the first differential amplifier 231e toward the reference potential, the first feedback coil 231f and the first shunt resistor 231h are connected in series in this order.

[0044] With the connection configuration shown above, the first differential amplifier 231e outputs a signal corresponding to the change in the resistance values of the first one-sided element 231c and the first other-sided element 231d that constitute the full-bridge circuit from its output terminal. This change in the resistance value is caused by the magnetic field along the shield facing surface 21 passing through the first one-sided element 231c and the first other-sided element 231d. A magnetic field generated by the current flowing through the conductive bus bar 50 passes through the first one-sided element 231c and the first other-sided element 231d. This magnetic field is the measured magnetic field to be measured. Therefore, a current corresponding to the measured magnetic field flows through the input terminals of the first differential amplifier 231e.

[0045] The input terminals and output terminals of the first differential amplifier 231e are connected via a feedback circuit not shown. For this reason, the first differential amplifier 231e is in a virtual short. Therefore, the first differential amplifier 231e operates so that the inverting input terminal and the non-inverting input terminal have the same potential. That is, the first differential amplifier 231e operates so that the current flowing through the input terminals and the current flowing through the output terminals become zero. As a result, a current corresponding to the measured magnetic field, that is, a feedback current, flows from the output terminal of the first differential amplifier 231e.

[0046] The feedback current flows between the output terminal of the first differential amplifier 231e and the reference potential via the first feedback coil 231f and the first shunt resistor 231h. Due to the flow of this feedback current, a canceling magnetic field is generated in the first feedback coil 231f. This canceling magnetic field penetrates the first magnetoelectric conversion unit 231a. As a result, the measured magnetic field penetrating the first magnetoelectric conversion unit 231a is canceled. Thus, the first magnetoelectric conversion unit 231a operates so that the measured magnetic field penetrating itself and the canceling magnetic field are balanced. A feedback voltage corresponding to the amount of the feedback current generating the canceling magnetic field is generated at the midpoint between the first feedback coil 231f and the first shunt resistor 231h. This feedback voltage is output to the first processing circuit 231b as an electrical signal detecting the measured current.

[0047] The first processing circuit 231b includes a first adjustment amplifier 231j and a first threshold power supply 231k. The non-inverting input terminal of the first adjustment amplifier 231j is connected to the midpoint between the first feedback coil 231f and the first shunt resistor 231h. Also, the first threshold power supply 231k is connected to the inverting input terminal of the first adjustment amplifier 231j. Thereby, the first adjustment amplifier 231j outputs a differentially amplified feedback voltage.

[0048] Incidentally, the resistance values of the first one-side element 231c and the first other-side element 231d constituting the full-bridge circuit each have a property dependent on temperature. Therefore, the output of the first adjustment amplifier 231j varies due to temperature changes. Thus, the first processing circuit 231b has a non-volatile memory that stores the relationship between the temperature and the resistance value of the magnetoresistive element. This non-volatile memory can be electrically rewritten with the stored information.

[0049] Furthermore, the first processing circuit 231b is connected to a first thermistor 71 and a second thermistor 72, which will be described later, for detecting temperature. The first processing circuit 231b may adjust the gain and offset of the first regulating amplifier 231j by rewriting the information stored in the non-volatile memory based on the temperature information detected by the first thermistor 71 and the second thermistor 72. This makes it possible to correct fluctuations in the output of the first regulating amplifier 231j caused by temperature changes. <Filter> The first filter 232 has a first resistor 232a and a first capacitor 232b. As shown in Figure 10, the wiring board 20 has a wiring pattern formed thereon, which includes a first power supply wiring 232c, a first output wiring 232d, and a first ground wiring 232e. The first ASIC 231 is connected to the first power supply wiring 232c, the first output wiring 232d, and the first ground wiring 232e, respectively. Furthermore, the first adjustment amplifier 231j of the first ASIC 231 has its output terminal connected to the first output wiring 232d.

[0050] The first resistor 232a of the first filter 232 is provided on the first output wiring 232d. The first capacitor 232b connects the first output wiring 232d and the first ground wiring 232e. As a result, the first filter 232 of the first sensing unit 23 is configured as a low-pass filter by the first resistor 232a and the first capacitor 232b. The output of the first ASIC 231 is output to the battery ECU 200 via this low-pass filter. As a result, the first sensing unit 23 outputs a signal from which high-frequency noise has been removed to the battery ECU 200. As described above, the first sensing unit 23 outputs an electrical signal corresponding to the DC current flowing through the conductive busbar 50 as a magnetic detection signal to the battery ECU 200.

[0051] The first sensing unit 23 of this embodiment has the configuration described above. The first sensing unit 23 and the second sensing unit 24 of this embodiment have the same configuration. Specifically, the second sensing unit 24 has a second magnetoelectric conversion unit 241a corresponding to the first magnetoelectric conversion unit 231a, and a second processing circuit 241b corresponding to the first processing circuit 231b. The second magnetoelectric conversion unit 241a has a second one-side element 241c corresponding to the first one-side element 231c, a second other-side element 241d corresponding to the first other-side element 231d, and a second differential amplifier 241e corresponding to the first differential amplifier 231e. Furthermore, the second magnetoelectric conversion unit 241a has a second feedback coil 241f corresponding to the first feedback coil 231f, and a second shunt resistor 241h corresponding to the first shunt resistor 231h.

[0052] The second processing circuit 241b has a second adjusting amplifier 241j corresponding to the first adjusting amplifier 231j and a second threshold power supply 241k corresponding to the first threshold power supply 231k. The second filter 242 has a second resistor 242a corresponding to the first resistor 232a and a second capacitor 242b corresponding to the first capacitor 232b. As shown in Figure 10, the wiring board 20 has a second power supply wiring 242c corresponding to the first power supply wiring 232c, a second output wiring 242d corresponding to the first output wiring 232d, and a second ground wiring 242e corresponding to the first ground wiring 232e. The second ASIC 241 is connected to the second power supply wiring 242c, the second output wiring 242d, and the second ground wiring 242e, respectively. The output terminal of the second adjusting amplifier 241j of the second ASIC 241 is connected to the second output wiring 242d.

[0053] The second resistor 242a of the second filter 242 is provided on the second output wiring 242d. The second capacitor 242b connects the second output wiring 242d and the second ground wiring 242e. As a result, the second filter 242 of the second sensing unit 24 constitutes a low-pass filter with the second resistor 242a and the second capacitor 242b. The output of the second ASIC 241 is output to the battery ECU 200 via this low-pass filter. As a result, the second sensing unit 24 outputs a signal from which high-frequency noise has been removed to the battery ECU 200. In this way, the second sensing unit 24 also outputs an electrical signal corresponding to the DC current flowing through the conductive busbar 50 as a magnetic detection signal to the battery ECU 200.

[0054] The second processing circuit 241b, like the first processing circuit 231b, has a non-volatile memory that stores the relationship between the temperature and resistance of the magnetoresistive element. The second processing circuit 241b may adjust the gain and offset of the second adjustment amplifier 241j by rewriting the information stored in the non-volatile memory based on the temperature information detected by the first thermistor 71 and the second thermistor 72. This makes it possible to correct fluctuations in the output of the second adjustment amplifier 241j caused by temperature changes.

[0055] Furthermore, the first magnetoelectric conversion unit 231a of the first sensing unit 23 and the second magnetoelectric conversion unit 241a of the second sensing unit 24 are aligned in the second direction D2. In addition, the first magnetoelectric conversion unit 231a and the second magnetoelectric conversion unit 241a are symmetrically arranged with respect to the center of the resistive unit 51 of the conductive busbar 50 (described later), and their positions in the first direction D1 are the same. For this reason, the magnetic field passing through the first magnetoelectric conversion unit 231a and the second magnetoelectric conversion unit 241a are the same. Consequently, the electrical signal input from the first sensing unit 23 to the battery ECU 200 and the electrical signal input from the second sensing unit 24 to the battery ECU 200 are the same. The battery ECU 200 determines whether or not an abnormality has occurred in either the first sensing unit 23 or the second sensing unit 24 by comparing these two input electrical signals. In this way, the current detection device 1 according to this embodiment has redundancy. The first sensing unit 23 and the second sensing unit 24 correspond to magnetic detection units that output a magnetic field detection signal corresponding to the magnetic field to be measured, which is generated when current flows through the conductive busbar 50.

[0056] Furthermore, the first one-sided element 231c, the first other-sided element 231d, the second one-sided element 241c, and the second other-sided element 241d constituting the full-bridge circuit do not all have to be magnetoresistive elements. The full-bridge circuit only needs to have at least one of the first one-sided element 231c, the first other-sided element 231d, the second one-sided element 241c, and the second other-sided element 241d be a magnetoresistive element. Alternatively, it may consist of only one half-bridge circuit instead of a full-bridge circuit. Also, if the above-mentioned redundancy is not required by the first sensing unit 23 and the second sensing unit 24, the current detection device 1 may adopt a configuration having only one of the first sensing unit 23 and the second sensing unit 24.

[0057] The third sensing unit 25 is mainly composed of ICs and a microcontroller, and includes a CPU, ROM, flash memory, RAM, I / O, drive circuit, AD converter, low-pass filter, communication circuit, and bus lines connecting these components. The ROM stores the temperature coefficient of resistance, which shows the relationship between the electrical resistance value of the resistor 51 (described later) that changes with temperature and the temperature. IC, I / O, and AD are abbreviations for Integrated Circuit, Input / Output, and Analog-Digital, respectively. The ROM and RAM of the third sensing unit 25 are composed of non-transitional physical storage media.

[0058] The third sensing unit 25 is electrically connected to the first thermistor 71 and the second thermistor 72 via the wiring pattern of the wiring board 20. The third sensing unit 25, the first thermistor 71, and the second thermistor 72 are also electrically connected to the conductive busbar 50 via a connection part 60 for connecting the wiring board 20 to the conductive busbar 50. As shown in Figure 5, the connection part 60 has a first connection pin 61, which is a first connection part, and a second connection pin 62, which is a second connection part. The sides of the first connection pin 61 and the second connection pin 62 that connect to the wiring board 20 are inserted into through-holes formed through the wiring board 20 and fixed with solder (not shown).

[0059] Therefore, the third sensing unit 25 acquires signals from the first thermistor 71 and the second thermistor 72 via the wiring pattern of the wiring board 20. The third sensing unit 25 also acquires signals from the first connection pin 61 and the second connection pin 62, respectively, via the solder fixing the first connection pin 61 and the second connection pin 62 and the wiring pattern of the wiring board 20. Then, as will be described later, the third sensing unit 25 detects and calculates the current flowing from the battery VT based on these acquired signals. The method of current detection and calculation by the third sensing unit 25 will be described later. <Shielding> The first shield 30 and the second shield 40 are made of a material with higher magnetic permeability than the sensor housing 10. Therefore, electromagnetic noise, which is external noise that tries to penetrate from the outside to the inside of the current detection device 1, tries to pass through the first shield 30 and the second shield 40. This makes it possible to suppress the input of external noise to the first magnetoelectric conversion unit 231a and the second magnetoelectric conversion unit 241a.

[0060] As shown in Figure 3, the first shield 30 and the second shield 40 each have a plate shape with a thin thickness in the third direction D3. As shown in Figures 11 and 12, the first shield 30 has a first surface 31 on one side in the third direction D3 and a first back surface 32 on the other side in the third direction D3. As shown in Figures 13 and 14, the second shield 40 has a second surface 41 on the other side in the third direction D3 and a second back surface 42 on one side in the third direction D3. As shown in Figure 3, the first shield 30 and the second shield 40 are provided in the sensor housing 10 in such a manner that the first back surface 32 and the second back surface 42 face each other in the third direction D3 via the wiring board 20. In addition, the first surface 31 of the first shield 30 is exposed to the outside of the sensor housing 10. The second surface 41 of the second shield 40 is exposed to the outside of the sensor housing 10. These first surface 31 and second surface 41 each constitute a part of the outermost surface of the current detection device 1.

[0061] The first shield 30 and the second shield 40 can be manufactured by pressing together a plurality of flat plates made of a soft magnetic material with high magnetic permeability, such as permalloy. Alternatively, the first shield 30 and the second shield 40 can be manufactured by rolling electrical steel. In this embodiment, the first shield 30 and the second shield 40 can each be manufactured by pressing together a plurality of flat plates made of a soft magnetic material. Each of the plurality of flat plates has four protrusions that protrude from its surface. Accordingly, each of the plurality of flat plates has four recesses that are recessed from the back surface toward the front surface. These plurality of flat plates are arranged so that their respective front and back surfaces face each other. The first shield 30 and the second shield 40 are manufactured by stacking the plurality of flat plates by fitting the protrusions of one of the two opposing flat plates into the recesses of the other flat plate, and then pressing together the plurality of flat plates in a stacked state.

[0062] Furthermore, when manufacturing the first shield 30 and the second shield 40 by rolling electrical steel, the direction in which the electrical steel is stretched by rolling is set to, for example, the first direction D1. In this case, the atomic arrangement of the electrical steel is aligned in the first direction D1. As a result, the permeability of the first shield 30 and the second shield 40 is higher in the first direction D1 than in the second direction D2. By specifying the rolling direction of the electrical steel in this way, anisotropy can be introduced into the permeability of the first shield 30 and the second shield 40. <First Shield> As shown in Figures 11 and 12, the first shield 30 has a planar shape in a direction view along the third direction D3 that forms a rectangle with the first direction D1 as the extension direction. The first shield 30 of this embodiment has notches 33 formed at the four corners. In Figures 11 and 12, to clarify the boundaries between the center and both ends of the first shield 30 in the second direction D2, these boundaries are shown by two dashed lines extending in the first direction D1. Hereinafter, as shown in Figures 11 and 12, the center of the first shield 30 in the second direction D2 is referred to as the first central portion 34, and the ends of the first shield 30 in the second direction D2 are referred to as the first end portions 35. The first central portion 34 is located in the second direction D2 between the two ends of the first end portions 35.

[0063] The length of the first ends 35 in the first direction D1 is shorter than that of the first central portion 34. Therefore, the permeability of the first ends 35 in the first direction D1 is lower than that of the first central portion 34, making it difficult for a magnetic field to penetrate the first ends 35. Consequently, the transmission of a magnetic field from one end of the first ends 35 to the other through the portion of the first central portion 34 that is directly connected to the first ends 35 and aligned in the second direction D2 is suppressed. As a result, it is difficult for a magnetic field to penetrate the portion of the first central portion 34 aligned in the second direction D2. Consequently, the portion of the first central portion 34 aligned in the second direction D2 is less likely to experience magnetic saturation. This portion of the first central portion 34 aligned in the second direction D2, where magnetic saturation is suppressed, and the first sensing unit 23 and the second sensing unit 24 mounted on the wiring board 20 are aligned in the third direction D3. <Second Shield> The second shield 40 has a planar shape when viewed along the third direction D3, which is a rectangle with the first direction D1 as its extension, as shown in Figures 13 and 14. In Figures 13 and 14, in order to clarify the boundary between the center and both ends of the second shield 40 in the second direction D2, these boundaries between the center and both ends are shown by two dashed lines extending in the first direction D1. Hereinafter, as shown in Figures 13 and 14, the center of the second shield 40 in the second direction D2 is shown as the second central portion 43, and the ends of the second shield 40 in the second direction D2 are shown as the second end portions 44. The second central portion 43 is located in the second direction D2 between the two ends of the second end portions 44.

[0064] The second shield 40 has two edges 45 aligned in the first direction D1. The second shield 40 has extensions 46 formed on each of the two edges 45 on the second central portion 43 side, extending in the third direction D3. These two extensions 46 extend in the third direction D3 from the second surface 41 towards the second back surface 42. The extensions 46 form a rectangular parallelepiped with the second direction D2 as the extension direction. As described above, the extensions 46 are formed by bending multiple flat plates made of soft magnetic material after compression during the manufacturing of the second shield 40.

[0065] As described above, the first shield 30 and the second shield 40 are provided on the sensor housing 10 in such a manner that the first back surface 32 and the second back surface 42 face each other in a third direction D3 via the wiring board 20. In this state provided on the sensor housing 10, the extension portion 46 extends toward the first shield 30. The end face of the extension portion 46 faces the first back surface 32 of the first central portion 34 of the first shield 30 in a third direction D3.

[0066] As a result, the separation distance in the third direction D3 between the first central portion 34 of the first shield 30 and the extended portion 46 of the second shield 40 is shorter than the separation distance in the third direction D3 between the first back surface 32 of the first shield 30 and the second back surface 42 of the second shield 40. Therefore, magnetic fields that enter the first shield 30 can easily pass through the extended portion 46 to the second shield 40.

[0067] As described above, the extension portion 46 extends from the second central portion 43 side of the end edge 45 in the third direction D3. Furthermore, the extension portion 46 is not formed on the second end portions 44 side of the end edge 45. For this reason, the magnetic field that enters the first shield 30 can easily pass through the extension portion 46 to the second central portion 43 of the second shield 40. This second central portion 43 and the first magnetoelectric conversion unit 231a and the second magnetoelectric conversion unit 241a mounted on the wiring board 20 face each other in the third direction D3.

[0068] Furthermore, the positions in the first direction D1 of the first magnetoelectric conversion section 231a and the second magnetoelectric conversion section 241a are located between two extensions 46 formed on each of the two end edges 45. Therefore, when external noise along the first direction D1 attempts to pass through the region between the first back surface 32 of the first shield 30 and the second back surface 42 of the second shield 40, the external noise attempts to penetrate the extensions 46 rather than the first magnetoelectric conversion section 231a and the second magnetoelectric conversion section 241a. The external noise that penetrates the extensions 46 has its direction of transmission bent so that it can pass through the second shield 40. As a result, the transmission of external noise through the first magnetoelectric conversion section 231a and the second magnetoelectric conversion section 241a is suppressed. <Conductive Busbar> As shown in Figures 2 to 7, the conductive busbar 50 extends in the second direction D2 and has a flattened shape with a thin thickness in the third direction D3. Furthermore, the conductive busbar 50 has a resistive section 51, a first busbar section 52, and a second busbar section 53. The conductive busbar 50 is configured such that current flows from the battery VT to the inverter INV when the battery VT is connected to the first busbar section 52 and the energized busbar BU is connected to the second busbar section 53. As shown in Figures 4 and 5, the battery VT has a battery connection section VT1 connected to the first busbar section 52. The energized busbar BU also has a busbar connection section BU1 connected to the second busbar section 53. The first busbar section 52 corresponds to the first conductive section, and the second busbar section 53 corresponds to the second conductive section. The battery connection section VT1 corresponds to the first forming section connected to the first busbar section 52 in the conductive path forming section that forms a conductive path through which current flows. The busbar connection section BU1 corresponds to the second forming section connected to the second busbar section 53 in the conductive path forming section that forms a conductive path through which current flows.

[0069] The resistor 51, the first busbar 52, and the second busbar 53 have a constant size in the first direction D1 from one end to the other in the second direction D2. The resistor 51 is formed in a rectangular shape extending in the first direction D1 when viewed along the third direction D3. The first busbar 52 and the second busbar 53 are formed in a rectangular shape extending in the second direction D2 when viewed along the third direction D3. Furthermore, the dimension of the resistor 51 in the third direction D3 is smaller than the dimension of the first busbar 52 and the second busbar 53 in the third direction D3. In other words, the resistor 51 is thinner than the first busbar 52 and the second busbar 53. Also, the dimension of the resistor 51 in the second direction D2 is smaller than the dimension of the first busbar 52 and the second busbar 53 in the second direction D2.

[0070] The resistive element 51 is a shunt resistive element and is conductive. Specifically, the resistive element 51 is formed in the shape of a plate from a copper alloy containing manganese and nickel. One side of the resistive element 51 in the second direction D2 is connected to the first busbar 52 by welding or the like. Furthermore, the other side of the resistive element 51 in the second direction D2 is connected to the second busbar 53 by welding or the like. The resistive element 51 has its own electrical resistance to be greater than that of the first busbar 52 and the second busbar 53. In this embodiment, the resistive element 51 has significantly higher electrical resistance than the first busbar 52 and the second busbar 53. Therefore, when current flows through the conductive busbar 50, the temperature of the conductive busbar 50 rises, and the resistive element 51 rises to a higher temperature than the first busbar 52 and the second busbar 53.

[0071] The first busbar portion 52 and the second busbar portion 53 are formed from conductive materials such as copper, brass, and aluminum. As a result, the first busbar portion 52 and the second busbar portion 53 are electrically conductive. In this embodiment, the first busbar portion 52 and the second busbar portion 53 are made of the same material and have approximately equal thermal resistance per unit volume. In this embodiment, the first busbar portion 52 and the second busbar portion 53 are both formed from copper, for example. The first busbar portion 52 and the second busbar portion 53 are formed in a rectangular parallelepiped shape in which the dimension in the second direction D2 is larger than the dimension in the first direction D1.

[0072] The first busbar portion 52 is formed of a material with lower electrical resistance than the resistor portion 51 and is provided on one side of the resistor portion 51 in the second direction D2. The first busbar portion 52 has a first connection hole 521 into which a first bolt B1 for electrically and mechanically connecting the battery VT and the current detection device 1 is inserted. The first connection hole 521 is formed to penetrate the first busbar portion 52 in the third direction D3. The first busbar portion 52 is fastened to the battery VT by a first nut N1 after the first bolt B1 is inserted into the first connection hole 521 and into the battery through hole VTH formed in the battery connection portion VT1 shown in Figure 5. Specifically, the first nut N1 is tightened from the tip side to the head side of the shaft of the first bolt B1, which is inserted into the first connection hole 521 and the battery through hole VTH, and the first busbar portion 52 and the battery connection portion VT1 are clamped between the head of the first bolt B1 and the first nut N1. As a result, the first busbar portion 52 and the battery VT come into contact, and the first busbar portion 52 and the battery VT are electrically and mechanically connected.

[0073] Furthermore, as shown in Figure 5, the first busbar portion 52 has a first connecting pin 61 connected to the first busbar surface 522 on the side facing the wiring board 20 in the third direction D3. The first busbar portion 52 and the first connecting pin 61 are fixed to each other, for example, by welding. In this way, the first busbar portion 52 and the first connecting pin 61 are electrically and mechanically connected. The first busbar portion 52 is then electrically and mechanically connected to the wiring board 20 via the first connecting pin 61 and solder used to fix the first connecting pin 61 to the wiring board 20.

[0074] The second busbar portion 53 is formed of a material with lower electrical resistance than the resistance portion 51 and is located on the other side of the resistance portion 51 in the second direction D2. The second busbar portion 53 has a second connection hole 531 into which a second bolt B2 for connecting the current detection device 1 and the energized busbar BU is inserted. The second connection hole 531 is formed to penetrate the second busbar portion 53 in the third direction D3. The second busbar portion 53 is fastened to the energized busbar BU by a second nut N2 after the second bolt B2 is inserted into the second connection hole 531 and into the busbar through hole BUH formed in the busbar connection portion BU1 shown in Figure 5. Specifically, the second nut N2 is tightened from the tip side to the head side of the shaft of the second bolt B2, which is inserted into the second connection hole 531 and the busbar through hole BUH, and the second busbar portion 53 and the busbar connection portion BU1 are clamped between the head of the second bolt B2 and the second nut N2. As a result, the second busbar portion 53 and the energized busbar BU come into contact, and the second busbar portion 53 and the energized busbar BU are electrically and mechanically connected.

[0075] The first connecting hole 521 and the second connecting hole 531 have approximately equal inner diameters, and bolts with equal outer diameters can be inserted into each. For example, the first connecting hole 521 and the second connecting hole 531 are set to have an inner diameter of 6.5 mm, and a first bolt B1 and a second bolt B2 with an outer diameter of 6 mm can be inserted into them. The first bolt B1 corresponds to the first fastening member, and the second bolt B2 corresponds to the second fastening member.

[0076] In this embodiment, as shown in Figure 5, the size of the first direction D1 of the battery connection part VT1 and the size of the first direction D1 of the busbar connection part BU1 are approximately equal to each other. Also, the size of the third direction D3 of the battery connection part VT1 and the size of the third direction D3 of the busbar connection part BU1 are approximately equal to each other. Therefore, when current flows through the conductive busbar 50, the electrical resistance between the connection part for allowing current to flow from the battery VT to the conductive busbar 50 and the connection part for allowing current to flow from the conductive busbar 50 to the energized busbar BU are approximately equal.

[0077] Furthermore, the second busbar portion 53 has a second connecting pin 62 connected to the second busbar surface 532 on the side facing the wiring board 20 in the third direction D3. The second busbar portion 53 and the second connecting pin 62 are fixed to each other, for example, by welding. As a result, the second busbar portion 53 and the second connecting pin 62 are electrically and mechanically connected. The second busbar portion 53 is then electrically and mechanically connected to the wiring board 20 via the second connecting pin 62 and solder used to fix the second connecting pin 62 to the wiring board 20.

[0078] The second busbar portion 53 has a dimension in the third direction D3 that is approximately equal to the dimension in the third direction D3 of the first busbar portion 52. That is, the first busbar portion 52 and the second busbar portion 53 have approximately equal thicknesses. However, the dimension in the second direction D2 of the second busbar portion 53 is larger than that of the first busbar portion 52 in the second direction D2.

[0079] Here, the end of the first busbar section 52 connected to the resistance section 51 is designated as the first one-sided end 523, and the end opposite to the side connected to the resistance section 51 is designated as the first other-sided end 524, with the distance from the first one-sided end 523 to the first other-sided end 524 being defined as the first busbar length L1. Similarly, the end of the second busbar section 53 connected to the resistance section 51 is designated as the second one-sided end 533, and the end opposite to the side connected to the resistance section 51 is designated as the second other-sided end 534, with the distance from the second one-sided end 533 to the second other-sided end 534 being defined as the second busbar length L2. The second busbar length L2 is larger than the first busbar length L1. For this reason, the first busbar section 52 and the second busbar section 53 have a non-symmetrical shape with respect to the axis of symmetry SL, when the axis of symmetry SL is defined as the center line passing through the center in the second direction D2 of the resistance section 51 and along the first direction D1.

[0080] Furthermore, the distance from the first other end 524 to the first connection hole 521 is approximately equal to the distance from the second other end 534 to the second connection hole 531. In contrast, the distance from the first one end 523 to the first connection hole 521 is smaller than the distance from the second one end 533 to the second connection hole 531. That is, the distance from the resistance portion 51 to the first connection hole 521 in the second direction D2 is shorter than the distance from the resistance portion 51 to the second connection hole 531 in the second direction D2. In other words, the distance from the resistance portion 51 to the second connection hole 531 in the second direction D2 is greater than the distance from the resistance portion 51 to the first connection hole 521 in the second direction D2. Furthermore, the distance from the target axis SL to the center of the first hole CL1, which is the center of the inner diameter of the first connecting hole 521, is smaller than the distance from the target axis SL to the center of the second hole CL2, which is the center of the inner diameter of the second connecting hole 531.

[0081] Thus, in the first busbar section 52 and the second busbar section 53, which are composed of the same material and formed in a non-symmetric shape with respect to the symmetric axis SL, the thermal resistance of the second busbar section 53 is greater than that of the first busbar section 52. Therefore, when current flows through the conductive busbar 50, the temperature of the first busbar section 52 and the second busbar section 53 rises, and the temperature of the second busbar section 53 rises to a higher level than that of the first busbar section 52.

[0082] The first busbar section 52 and the second busbar section 53 can be manufactured, for example, by press-forming a flat plate. Alternatively, the first busbar section 52 and the second busbar section 53 may be manufactured by integrally connecting a plurality of flat plates, or by welding a plurality of flat plates. Alternatively, the first busbar section 52 and the second busbar section 53 can also be manufactured by pouring molten conductive material into a mold. The manufacturing method of the first busbar section 52 and the second busbar section 53 is not particularly limited.

[0083] The first connecting pin 61 is made of a conductive material such as copper or gold and is formed in a rod shape. The first connecting pin 61 has a first connecting support portion 611 that is connected to the first busbar surface 522 and a first connecting detection portion 612 that is connected to the wiring board 20. The first connecting pin 61 has the first connecting support portion 611 and the first connecting detection portion 612 integrally formed and is formed by bending.

[0084] The first connecting support portion 611 is positioned on the first busbar surface 522, extending along the second direction D2 from the first other end portion 524 towards the first one end portion 523. The end of the first connecting support portion 611 on the first one end portion 523 side is positioned so that it overlaps with the first one end portion 523 in the third direction D3.

[0085] The first connection detection unit 612 is formed extending along the third direction D3, with one end communicating with the first connection support unit 611 and the other end penetrating the wiring board 20. Specifically, the end of the first connection detection unit 612 opposite to the side connected to the first connection support unit 611 is inserted into a through-hole formed through the wiring board 20, and protrudes from the shield-facing surface 21 of the wiring board 20. The first connection detection unit 612 is also connected to the wiring board 20 by solder.

[0086] The second connecting pin 62 is made of a conductive material such as copper or gold and is formed in a rod shape. The second connecting pin 62 has a second connecting support portion 621 that is connected to the second busbar surface 532 and a second connecting detection portion 622 that is connected to the wiring board 20. The second connecting pin 62 has the second connecting support portion 621 and the second connecting detection portion 622 integrally formed and is formed by bending.

[0087] The second connecting support portion 621 is positioned on the second busbar surface 532, extending along the second direction D2 from the second other end portion 534 towards the second one end portion 533. The end of the second connecting support portion 621 on the second one end portion 533 side is positioned so that it overlaps with the second one end portion 533 in the third direction D3.

[0088] The second connection detection unit 622 is formed extending along the third direction D3, with one end communicating with the second connection support unit 621 and the other end penetrating the wiring board 20. Specifically, the end of the second connection detection unit 622 opposite to the side connected to the second connection support unit 621 is inserted into a through-hole formed through the wiring board 20, and protrudes from the shield-facing surface 21 of the wiring board 20. The second connection detection unit 622 is also connected to the wiring board 20 by solder. As shown in Figure 5, a first thermistor 71 and a second thermistor 72 for detecting the temperature of the conductive busbar 50 are arranged around the area on the wiring board 20 to which the second connection detection unit 622 is connected. <Thermistors> The first thermistor 71 and the second thermistor 72 are temperature detection units for detecting the temperature of the conductive busbar 50. As shown in Figures 5 and 9, the first thermistor 71 and the second thermistor 72 are mounted on the busbar-facing surface 22 of the wiring board 20. Specifically, the first thermistor 71 and the second thermistor 72 are mounted around the through-hole into which the second connection pin 62 is inserted on the busbar-facing surface 22. For this reason, the first thermistor 71 and the second thermistor 72 are positioned closer to the second connection detection unit 622 than to the first connection detection unit 612. In other words, the first thermistor 71 is positioned such that the distance from the second connection pin 62 to the first thermistor 71 is smaller than the distance from the first connection pin 61 to the first thermistor 71. Similarly, the second thermistor 72 is positioned such that the distance from the second connection pin 62 to the second thermistor 72 is smaller than the distance from the first connection pin 61 to the second thermistor 72.

[0089] The first thermistor 71 and the second thermistor 72 are aligned in the second direction D2 and are positioned symmetrically with respect to the second connection detection unit 622, on one side and the other side of the second connection detection unit 622 in the second direction D2. Therefore, the distance in the second direction D2 from the first thermistor 71 to the second connection detection unit 622 is approximately equal to the distance in the second direction D2 from the second thermistor 72 to the second connection detection unit 622. In this embodiment, the first thermistor 71 and the second thermistor 72 are positioned as close to the second connection detection unit 622 as possible without contacting it.

[0090] The first thermistor 71 and the second thermistor 72, arranged in this manner, detect the temperature of the resistive portion 51 via the wiring pattern formed on the busbar-facing surface 22, the solder used to fix the second connection pin 62 to the wiring board 20, the second connection pin 62, and the second busbar portion 53. The first thermistor 71 and the second thermistor 72 output an electrical signal corresponding to the detected temperature of the resistive portion 51 as a temperature detection signal to the third sensing unit 25.

[0091] As described above, the battery management system VMS and the current detection device 1 are configured as described. The temperature detection device of this embodiment is configured including the conductive busbar 50, the first thermistor 71, the second thermistor 72, and the connection part 60 as described above. Next, the method for detecting and calculating the current flowing from the battery VT to the inverter INV by the third sensing unit 25 of the current detection device 1 will be described.

[0092] When the battery VT discharges, the discharged current flows to the inverter INV via the current detection device 1, the energized busbar BU, and the system main relay SMR. The current flowing through the current detection device 1 flows through the conductive busbar 50 in the order of the first busbar section 52, the resistor section 51, and the second busbar section 53. When current flows through the current detection device 1, the third sensing unit 25 detects the voltage applied to the first busbar section 52 side of the resistor section 51 via the first connection pin 61, and detects the voltage applied to the second busbar section 53 side of the resistor section 51 via the second connection pin 62. The third sensing unit 25 also obtains temperature detection signals corresponding to the temperature of the resistor section 51 from the first thermistor 71 and the second thermistor 72.

[0093] The third sensing unit 25 corrects the electrical resistance of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72, and the temperature coefficient of resistance, which shows the relationship between the electrical resistance of the resistor 51 and temperature, stored in the RAM. Then, the third sensing unit 25 calculates the current flowing through the conductive busbar 50 based on Ohm's law, using the corrected electrical resistance of the resistor 51, the voltage applied to the first busbar 52, and the voltage applied to the second busbar 53. The third sensing unit 25 outputs an electrical signal corresponding to the current flowing through the conductive busbar 50 as a current detection signal to the battery ECU 200. The battery ECU 200 monitors the SOC of the battery VT based on the electrical signal obtained from the current detection device 1 and controls the charging of the battery VT. The third sensing unit 25, functioning in this way, corresponds to the resistance correction unit and the current detection unit.

[0094] By the way, in order to correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72, it is required that the temperature of the resistor 51 be detected accurately by the first thermistor 71 and the second thermistor 72. However, the first thermistor 71 and the second thermistor 72 are connected to the resistor 51 via a wiring pattern formed on the busbar-facing surface 22, solder for fixing the second connection pin 62 to the wiring board 20, the second connection pin 62, and the second busbar 53. In other words, the wiring board 20, solder for fixing the second connection pin 62 to the wiring board 20, the second connection pin 62, and the second busbar 53 are interposed between the first thermistor 71 and the second thermistor 72 and the resistor 51.

[0095] Therefore, the temperature directly detected by the first thermistor 71 and the second thermistor 72 is not the direct temperature of the resistive section 51, but rather the temperature of the wiring pattern formed on the busbar-facing surface 22, which the first thermistor 71 and the second thermistor 72 directly contact. In addition, the heat from the resistive section 51 is transferred to the second busbar section 53, the second connecting pin 62, the solder used to fix the second connecting pin 62 to the wiring board 20, and the wiring pattern formed on the busbar-facing surface 22. The first thermistor 71 and the second thermistor 72 detect the temperature changes that occur as a result of the heat from the resistive section 51 being transferred to the second busbar section 53, the second connecting pin 62, the solder, and the wiring pattern.

[0096] However, the heat transmitted from the resistive section 51 is transferred in the following order: to the second busbar section 53, the second connecting pin 62, the solder used to fix the second connecting pin 62 to the wiring board 20, and the wiring pattern formed on the busbar-facing surface 22, causing its temperature to gradually decrease. Therefore, the temperatures detected by the first thermistor 71 and the second thermistor 72 will differ from the temperature of the resistive section 51. For this reason, it is important to bring the temperatures detected by the first thermistor 71 and the second thermistor 72 as close as possible to the temperature of the resistive section 51.

[0097] Furthermore, as described above, the electrical resistance of the resistor 51 in this embodiment is significantly higher than that of the first busbar 52 and the second busbar 53. Therefore, when current flows through the conductive busbar 50 and the temperature of the conductive busbar 50 rises, the temperature of the resistor 51 rises to a higher level than that of the first busbar 52 and the second busbar 53. Specifically, when current flows through the resistor 51 along the second direction D2, the temperature of the resistor 51 gradually increases as it moves away from the end to which the first busbar 52 is connected, and the highest temperature is reached at a predetermined distance from the end to which the first busbar 52 is connected. Then, the temperature of the resistor 51 gradually decreases from the highest temperature point towards the end to which the second busbar 53 is connected.

[0098] Furthermore, the first busbar section 52 and the second busbar section 53, which have lower electrical resistance compared to the resistor section 51, are at a lower temperature than the resistor section 51. Specifically, the temperature of the first busbar section 52 is higher closer to the first one-sided end 523, which is connected to the resistor section 51, and decreases as you move from the first one-sided end 523 towards the first other-sided end 524. Similarly, the temperature of the second busbar section 53 is higher closer to the second one-sided end 533, which is connected to the resistor section 51, and decreases as you move from the second one-sided end 533 towards the second other-sided end 534.

[0099] Therefore, when accurately detecting the temperature of the resistance portion 51, considering the temperature drop due to heat transfer, it is desirable to detect the temperature of the first one-sided end portion 523 or the second one-sided end portion 533, which are the parts closest to the temperature of the resistance portion 51. Furthermore, since the temperature of the first busbar portion 52 and the second busbar portion 53 will be lower than that of the resistance portion 51, it is desirable to bring the temperature of the first one-sided end portion 523 and the second one-sided end portion 533 as close as possible to the highest temperature of the resistance portion 51.

[0100] Here, in order to explain the temperatures of the resistive section 51, the first busbar section 52, and the second busbar section 53, we will first explain the temperature of the comparative conductive busbar 100 shown in Figure 15, which is a comparative example of the conductive busbar 50 of this embodiment. As shown in Figure 15, the comparative conductive busbar 100 is composed of a comparative resistive section 110, a comparative first busbar section 120, and a comparative second busbar section 130. The conductive busbar 50 of this embodiment and the comparative conductive busbar 100 have the same magnitude in the second direction D2. Also, the resistive section 51 and the comparative resistive section 110 of this embodiment have the same shape and configuration.

[0101] In contrast, the first busbar section 120 has a larger size in the second direction D2 compared to the first busbar section 52 of this embodiment. Other than this, the first busbar section 120 and the first busbar section 52 of this embodiment have similar shapes and configurations. The second busbar section 130 has a smaller size in the second direction D2 compared to the second busbar section 53 of this embodiment. Furthermore, the size of the second direction D2 in the second busbar section 130 is equal to that of the first busbar section 120. Therefore, the first busbar section 120 and the second busbar section 130 have shapes that are symmetrical with respect to the axis SL. The thermal resistances of the first busbar section 120 and the second busbar section 130 are approximately equal. Other than this, the second busbar section 130 and the second busbar section 53 of this embodiment have similar shapes and configurations.

[0102] The temperature changes of the first comparison busbar section 120, the comparison resistor section 110, and the second comparison busbar section 130 when current flows through the comparison conductive busbar 100 formed in this manner will be explained with reference to Figure 15. When current flows through the comparison conductive busbar 100, the temperature of the comparison conductive busbar 100 rises, as shown in Figure 15. Specifically, the temperature of the first comparison busbar section 120 rises continuously and gradually as it approaches the side to which the comparison resistor section 110 is connected, starting from the side opposite to the side to which the comparison resistor section 110 is connected.

[0103] Furthermore, the temperature of the comparative resistance section 110 rises continuously and gradually from the side to which the comparative first busbar section 120 is connected to the side to which the comparative second busbar section 130 is connected. However, because the electrical resistance of the comparative resistance section 110 is greater than that of the comparative first busbar section 120, the temperature rises more steeply compared to the temperature rise gradient of the comparative first busbar section 120. Hereinafter, when current flows through the conductive busbar 50 or the comparative conductive busbar 100, the amount of temperature change per unit distance when current flows in the second direction D2 is referred to as the temperature change rate. The temperature change rate when the temperature rises due to the flow of current through the comparative resistance section 110 is greater than the temperature change rate when the temperature rises due to the flow of current through the comparative first busbar section 120.

[0104] Furthermore, because the electrical resistance of the comparison resistance section 110 is greater than that of the comparison second busbar section 130, the temperature of the comparison resistance section 110 gradually decreases from a predetermined distance away from the side to which the comparison first busbar section 120 is connected towards the comparison second busbar section 130. For this reason, as shown in Figure 15, the temperature of the comparison resistance section 110 is highest at the center in the second direction D2, and the graph showing the temperature change is convex. Here, since the thermal resistances of the comparison first busbar section 120 and the comparison second busbar section 130 are approximately equal, the temperature of the comparison resistance section 110 is highest at the center in the second direction D2. Then, the temperature of the comparison resistance section 110 continuously and gradually decreases from the center in the second direction D2 towards the side to which the comparison second busbar section 130 is connected. The temperature of the comparison resistance section 110 is approximately the same on the side to which the first comparison busbar section 120 is connected and on the side to which the second comparison busbar section 130 is connected.

[0105] Furthermore, the temperature of the second comparison busbar section 130 decreases continuously and gradually as you move from the side to which the comparison resistor section 110 is connected to the side to which the comparison resistor section 110 is connected. However, because the electrical resistance of the second comparison busbar section 130 is smaller than that of the comparison resistor section 110, the temperature of the second comparison busbar section 130 decreases more slowly than the temperature decrease gradient of the comparison resistor section 110. In other words, the rate of temperature change due to the flow of current through the second comparison busbar section 130 is smaller than the rate of temperature change due to the flow of current through the comparison resistor section 110.

[0106] Thus, when the first comparison busbar section 120 and the second comparison busbar section 130 are symmetrical with respect to the symmetric axis SL, and their thermal resistances are approximately equal, the temperature of the comparison resistance section 110 is highest at its center in the second direction D2. The temperature of the comparison resistance section 110 decreases as you move away from the center. In other words, the temperature of the comparison resistance section 110 is lowest at the point where the first comparison busbar section 120 is connected and at the point where the second comparison busbar section 130 is connected.

[0107] Furthermore, the temperatures at the points where the first comparison busbar section 120 and the second comparison busbar section 130 are connected deviate the most from the temperature at the center of the comparison resistance section 110 in the second direction D2, which is the highest temperature. Also, the temperatures at the points where the first comparison busbar section 120 and the second comparison busbar section 130 are connected are lower than the average temperature of the comparison resistance section 110, which changes continuously in the second direction D2 as shown in Figure 15.

[0108] Furthermore, since the first comparison busbar section 120 and the second comparison busbar section 130 are connected to the comparison resistance section 110, the temperature of each part connected to the comparison resistance section 110 will be the temperature furthest from the highest temperature of the comparison resistance section 110. Similarly, the first connection support section 611 of the first connection pin 61 connected to the first comparison busbar section 120 and the second connection support section 621 of the second connection pin 62 connected to the second comparison busbar section 130 will also be the temperature furthest from the highest temperature of the comparison resistance section 110. In Figure 15, the temperature of the second connection support section 621 is indicated by a white circle.

[0109] Therefore, if the first thermistor 71 and the second thermistor 72 detect the temperature of the comparison resistor 110 via the second connection pin 62 connected to the comparison second busbar 130, the difference between the detected temperature and the actual temperature of the resistor 51 tends to be large. In this case, if the third sensing unit 25 corrects the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72, the electrical resistance value may not be corrected accurately, and the error in the current value calculated by the current detection device 1 may increase.

[0110] Next, the temperature changes of the first busbar section 52, the resistor section 51, and the second busbar section 53 when current flows through the conductive busbar 50 of this embodiment will be explained with reference to Figure 16.

[0111] As described above, in this embodiment, the conductive busbar 50 has a second busbar length L2 that is larger than the first busbar length L1. Furthermore, the first busbar section 52 and the second busbar section 53 have non-symmetrical shapes with respect to the symmetric axis SL, and the thermal resistance of the second busbar section 53 is greater than that of the first busbar section 52.

[0112] When current flows through the conductive busbar 50 formed in this manner, the temperature of the conductive busbar 50 rises, as shown in Figure 16. Specifically, the temperature of the first busbar portion 52 rises continuously and gradually as it approaches the first one-side end 523 from the first other-side end 524.

[0113] Furthermore, the temperature of the resistor 51 rises continuously and gradually from the side to which the first one-sided end 523 is connected to the side to which the second one-sided end 533 is connected. Because the electrical resistance of the resistor 51 is greater than that of the first busbar 52, the temperature rises more steeply compared to the temperature rise gradient of the first busbar 52. The temperature of the resistor 51 is highest at a predetermined distance from the end to which the first one-sided end 523 is connected. The temperature of the resistor 51 then gradually decreases continuously from the highest temperature point towards the end to which the second one-sided end 533 is connected.

[0114] The temperature of the second busbar section 53 decreases continuously and gradually from the second one-sided end 533 to the second other-sided end 534. However, because the electrical resistance of the second busbar section 53 is smaller than that of the resistance section 51, the temperature of the second busbar section 53 decreases more slowly than the temperature decrease gradient of the resistance section 51.

[0115] In this embodiment, the thermal resistance of the second busbar section 53 is greater than that of the first busbar section 52. Therefore, when current flows through the conductive busbar 50 and the temperatures of the first busbar section 52 and the second busbar section 53 rise, the second busbar section 53 rises to a higher temperature than the first busbar section 52.

[0116] As a result, the temperature of the resistor 51 on the side connected to the second busbar 53 is higher than the temperature of the side connected to the first busbar 52. The hottest part of the resistor 51 is located on the side of the second busbar 53 from the center in the second direction D2 of the resistor 51. In other words, the hottest part of the resistor 51 can be shifted towards the second busbar 53 from the hottest part of the comparison resistor 110. Furthermore, the temperature of the resistor 51 on the side to which the second one-side end 533 is connected is higher than the temperature of the part to which the first one-side end 523 is connected.

[0117] Thus, when the thermal resistance of the second busbar section 53 is greater than that of the first busbar section 52, the temperature of the resistance section 51 is highest at the part closer to the second busbar section 53 than at the center in the second direction D2. Furthermore, the temperature of the resistance section 51 at the part where the second one-sided end 533 of the second busbar section 53 is connected is higher than the temperature of the part where the first one-sided end 523 of the first busbar section 52 is connected. For this reason, the temperature difference between the highest temperature in the resistance section 51 and the temperature of the second one-sided end 533 is smaller than the temperature difference between the highest temperature in the resistance section 51 and the temperature of the first one-sided end 523. In other words, the temperature difference between the hottest parts of the second busbar section 53 and the resistance section 51 is smaller than the temperature difference between the hottest parts of the first busbar section 52 and the resistance section 51. Furthermore, the temperature at the point where the second one-sided end 533 of the resistance portion 51 is connected is higher than the average temperature of the resistance portion 51, which changes continuously in the second direction D2 shown in Figure 16.

[0118] Furthermore, the second one-sided end portion 533 connected to the resistor portion 51 reaches a temperature where the deviation from the highest temperature in the resistor portion 51 is suppressed. Similarly, the second connection support portion 621 of the second connection pin 62 connected to the second busbar portion 53 also reaches a temperature where the deviation from the highest temperature in the resistor portion 51 is suppressed. In Figure 16, the temperature of the second connection support portion 621 is indicated by a white circle.

[0119] In this embodiment, in order to suppress the temperature drop due to heat transfer to the first thermistor 71 and the second thermistor 72, the first thermistor 71 and the second thermistor 72 are positioned closer to the second connection pin 62 than to the first connection pin 61. Therefore, the temperature drop due to heat transfer to the first thermistor 71 and the second thermistor 72 is suppressed compared to the case where the first thermistor 71 and the second thermistor 72 are positioned closer to the first connection pin 61 than to the second connection pin 62.

[0120] Therefore, when the first thermistor 71 and the second thermistor 72 detect the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53, the temperature difference between the detected temperature and the temperature of the resistor 51 can be suppressed. As a result, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72. Consequently, the third sensing unit 25 can accurately detect the current value based on the accurately corrected electrical resistance value of the resistor 51.

[0121] As described above, the temperature detection device of this embodiment includes a flat conductive busbar 50 through which current flows in a second direction D2, and a first thermistor 71 and a second thermistor 72 that output a temperature detection signal corresponding to the temperature of the conductive busbar 50. The temperature detection device also includes a first connection pin 61 and a second connection pin 62 that connect the first thermistor 71 and the second thermistor 72 to the conductive busbar 50. The current detection device 1 also includes a third sensing unit 25 that corrects the electrical resistance value of the resistor 51 based on the temperature detection signal and outputs a current detection signal corresponding to the current flowing through the conductive busbar 50 based on the corrected electrical resistance value and the voltage applied to the conductive busbar 50. The conductive busbar 50 includes a resistive portion 51, a first busbar portion 52 having lower electrical resistance than the resistive portion 51 and provided on one side of the resistive portion 51 in the second direction D2, and a second busbar portion 53 having lower electrical resistance than the resistive portion 51 and provided on the other side of the resistive portion 51 in the second direction D2. The first thermistor 71 and the second thermistor 72 are positioned such that their distance from the second connection pin 62 is smaller than their distance from the first connection pin 61. The second busbar portion 53 has a higher thermal resistance than the first busbar portion 52.

[0122] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side of the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52. Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistive section 51 via the second connection pin 62 connected to the second busbar section 53 and the actual temperature of the resistive section 51 can be suppressed. Consequently, the first thermistor 71 and the second thermistor 72 can accurately detect the temperature of the resistive section 51. The third sensing unit 25 can accurately correct the electrical resistance value of the resistive section 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72, and can accurately detect the current value based on the corrected electrical resistance value of the resistive section 51.

[0123] Furthermore, according to the above embodiment, the following effects can be obtained.

[0124] (1) In the above embodiment, the first busbar portion 52 and the second busbar portion 53 have a non-symmetric shape with respect to the symmetric axis SL.

[0125] According to this, a difference in the thermal resistance of the first busbar section 52 and the second busbar section 53 can be created with a simple structure that involves a difference in the shape of the first busbar section 52 and the second busbar section 53.

[0126] (2) In the above embodiment, the second busbar section 53 has a larger size in the second direction D2 compared to the first busbar section 52.

[0127] According to this, a non-symmetrical shape can be achieved with a simple configuration that creates a difference in the dimensions of the first busbar section 52 and the second busbar section 53 in the second direction D2, and a difference in the thermal resistance of the first busbar section 52 and the second busbar section 53 can be created.

[0128] (First Modification of the First Embodiment) In the first embodiment described above, an example was described in which the second busbar length L2 is larger than the first busbar length L1, and the thermal resistance of the second busbar portion 53 is larger than the thermal resistance of the first busbar portion 52. However, the invention is not limited to this. For example, as shown in Figure 17, the second busbar length L2 may be smaller than the first busbar length L1, and the thermal resistance of the second busbar portion 53 may be smaller than the thermal resistance of the first busbar portion 52. In this case, the first thermistor 71 and the second thermistor 72 are arranged on the wiring board 20 around the portion to which the first connection pin 61 connected to the first busbar portion 52 is connected.

[0129] (Second Modification of the First Embodiment) In the first embodiment described above, an example was described in which the wiring board 20 and the conductive busbar 50 are connected by rod-shaped first connection pins 61 and second connection pins 62, but the invention is not limited to this. For example, as shown in Figure 18, the wiring board 20 and the conductive busbar 50 may be connected by solder S. When the wiring board 20 and the conductive busbar 50 are connected by solder S in this way, the solder S corresponds to the first connection portion and the second connection portion. In this case, the first thermistor 71 and the second thermistor 72 may be arranged on the shield-facing surface 21 side of the wiring board 20, rather than on the busbar-facing surface 22 side.

[0130] (Third Modification of the First Embodiment) In the first embodiment described above, an example was described in which the size of the first direction D1 is constant from one end to the other end of the second direction D2 for each of the first busbar portion 52 and the second busbar portion 53, but the invention is not limited to this. If the shape of the second busbar portion 53 has a greater thermal resistance than that of the first busbar portion 52, the size of the first direction D1 is not constant from one end to the other end of the second direction D2 for each of the first busbar portion 52 and the second busbar portion 53. For example, the first busbar portion 52 and the second busbar portion 53 may be formed with one end or the other end of the first direction D1 inclined with respect to the second direction D2, or they may be formed to protrude in the first direction D1 and bent.

[0131] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 19. In this embodiment, the size of the second connection hole 531 is different from that of the first embodiment. Other than this, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0132] As shown in Figure 19, the inner diameter of the second connection hole 531 in this embodiment is larger than that of the second connection hole 531 in the first embodiment. As a result, the inner diameter of the second connection hole 531 is larger than that of the first connection hole 521. For example, if the inner diameter of the first connection hole 521 is set to 6.5 mm, the inner diameter of the second connection hole 531 can be set to 7.5 mm or 8.5 mm, etc. However, the inner diameters of the first connection hole 521 and the second connection hole 531 are not limited. Hereinafter, the inner diameter of the first connection hole 521 will be referred to as the first inner diameter φ1, and the inner diameter of the second connection hole 531 will be referred to as the second inner diameter φ2.

[0133] The reason why the second inner diameter φ2 is larger than the first inner diameter φ1 will now be explained. As described above, the distance from the second connection hole 531 to the resistance portion 51 in the second direction D2 is greater than the distance from the first connection hole 521 to the resistance portion 51 in the second direction D2. Furthermore, the distance from the center of the second hole CL2, which is the center of the inner diameter of the second connection hole 531, to the target axis SL is greater than the distance from the center of the first hole CL1, which is the center of the inner diameter of the first connection hole 521, to the target axis SL.

[0134] Furthermore, the first busbar section 52 is fastened to the battery VT by tightening a nut onto the first bolt B1 inserted into the first connection hole 521 and the battery through hole VTH, with the head of the first bolt B1 and the first nut N1. As a result, the first busbar section 52 and the battery VT come into contact, and the first busbar section 52 and the battery VT are electrically and mechanically connected. Similarly, the second busbar section 53 is fastened to the energized busbar BU by tightening a second nut N2 onto the second bolt B2 inserted into the second connection hole 531 and the busbar through hole BUH, with the head of the second bolt B2 and the second nut N2. As a result, the second busbar section 53 comes into contact with the energized busbar BU, and the second busbar section 53 and the energized busbar BU are electrically and mechanically connected.

[0135] Here, the first bolt B1 inserted into the first connection hole 521 is generally used with an outer diameter that is a predetermined amount smaller than the first inner diameter φ1, from the viewpoint of ease of insertion. Similarly, the second bolt B2 inserted into the second connection hole 531 is generally used with an outer diameter that is a predetermined amount smaller than the second inner diameter φ2, from the viewpoint of ease of insertion. Furthermore, the greater the difference between the outer diameter of the first bolt B1 and the first inner diameter φ1, and the greater the difference between the outer diameter of the second bolt B2 and the second inner diameter φ2, the better the assembly can be. However, when the first bolt B1 is inserted into the first connection hole 521 or the second bolt B2 is inserted into the second connection hole 531, the axes of the first bolt B1 and the second bolt B2 may be offset from the center of the hole.

[0136] For example, when the first bolt B1 is inserted into the first connection hole 521 and the battery through hole VTH and the first nut N1 is tightened, the axis of the first bolt B1 and the center CL1 of the first hole may not coincide, and the first bolt B1 may be fastened shifted from the design position in a first direction D1 or the like. Also, when the second bolt B2 is inserted into the second connection hole 531 and the busbar through hole BUH and the second nut N2 is tightened, the axis of the second bolt B2 and the center CL2 of the second hole may not coincide, and the second bolt B2 may be fastened shifted from the design position in a second direction D2 or the like.

[0137] These misalignments increase the electrical resistance at the connection points between the conductive busbar 50 and the battery connection VT1, and between the conductive busbar 50 and the busbar connection BU1. Therefore, it is desirable to minimize the misalignment of the first bolt B1 and the second bolt B2 when they are inserted. However, to minimize misalignment, the smaller the difference between the first inner diameter φ1 and the outer diameter of the first bolt B1, and the smaller the difference between the second inner diameter φ2 and the outer diameter of the second bolt B2, the more difficult it becomes to assemble the conductive busbar 50 to the battery VT and the energized busbar BU. This reduces the ease of assembly of the current detection device 1.

[0138] Through diligent research by the inventors, it was found that the increase in electrical resistance due to the misalignment of the positions where the first bolt B1 and the second bolt B2 are inserted from their design positions varies depending on the distance from the resistance section 51. Specifically, it was found that the smaller the distance from the first connection hole 521 to the resistance section 51 and the smaller the distance from the second connection hole 531 to the resistance section 51, the greater the increase in electrical resistance due to the misalignment.

[0139] Furthermore, in this embodiment, the conductive busbar 50 has a distance in the second direction D2 from the second connection hole 531 to the resistance portion 51 that is greater than the distance in the second direction D2 from the first connection hole 521 to the resistance portion 51. Therefore, the effect of misalignment on electrical resistance is greater when the misalignment between the first connection hole 521 and the first bolt B1 is greater than when the misalignment between the second connection hole 531 and the second bolt B2.

[0140] For example, suppose the insertion position into the first connection hole 521 and the insertion position into the second connection hole 531 are shifted by the same amount in the first direction D1 from the design position. In this case, the increase in electrical resistance at the connection portion between the conductive busbar 50 and the battery connection portion VT1 is greater than the increase in electrical resistance at the connection portion between the conductive busbar 50 and the busbar connection portion BU1. In other words, of the first connection hole 521 and the second connection hole 531, the second connection hole 531, which is further from the resistance portion 51, is less affected by the increase in electrical resistance due to the shift in the insertion positions of the first bolt B1 and the second bolt B2 than the first connection hole 521, which is closer to the resistance portion 51.

[0141] Therefore, by making the second inner diameter φ2 larger than the first inner diameter φ1, it is possible to improve the assembly of the conductive busbar 50 and the energized busbar BU while suppressing the effect of increased electrical resistance caused by misalignment of the insertion positions of the first bolt B1 and the second bolt B2. Also, by making the first inner diameter φ1 smaller than the second inner diameter φ2, it is possible to suppress the increase in electrical resistance caused by misalignment of the insertion positions of the first bolt B1 and the second bolt B2.

[0142] The other configurations are the same as in the first embodiment. The current detection device 1 of this embodiment can obtain the same effects and advantages as in the first embodiment, which are achieved from a configuration that is the same as or equivalent to that of the first embodiment.

[0143] (Third Embodiment) Next, the third embodiment will be described with reference to Figure 20. In this embodiment, the shapes of the first busbar portion 52 and the second busbar portion 53 differ from those of the first embodiment. Other than this, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0144] As shown in Figure 20, the first busbar section 52 and the second busbar section 53 of this embodiment have equal magnitudes in the second direction D2. Specifically, the first busbar section 52 has a larger magnitude in the second direction D2 compared to the first busbar section 52 of the first embodiment. Also, the second busbar section 53 has a smaller magnitude in the second direction D2 compared to the second busbar section 53 of the first embodiment. As a result, the first busbar length L1 and the second busbar length L2 are equal.

[0145] Furthermore, the second busbar portion 53 of this embodiment has a narrow portion 535 in which the size of the first direction D1 is smaller compared to the size of the first direction D1 of other parts. The narrow portion 535 has a smaller size of the first direction D1 compared to other parts of the second busbar portion 53. Also, the narrow portion 535 has a smaller size of the first direction D1 compared to the size of the first busbar portion 52 in which the first direction D1 is smaller. For this reason, the size of the first direction D1 of the second busbar portion 53 of this embodiment is not constant from the second one-sided end 533 to the second other-sided end 534.

[0146] In this embodiment, the narrow portion 535 is formed by cutting out one end in the first direction D1 and the other end in the first direction D1 from the second other end 534 toward the second one end 533. The narrow portion 535 has a planar shape when viewed in the direction along the third direction D3 that is a rectangle extending in the second direction D2. However, the shape of the narrow portion 535 is not limited, and various shapes can be adopted as long as the size in the first direction D1 is smaller than the size in the first direction D1 of the other parts of the second busbar portion 53 and the size in the first direction D1 of the first busbar portion 52.

[0147] The first busbar portion 52 and the second busbar portion 53 of this embodiment, formed in this manner, have a non-symmetrical shape with respect to the axis of symmetry SL. Furthermore, the narrow portion 535 has a smaller cross-sectional area perpendicular to the second direction D2 compared to the cross-sectional area perpendicular to the second direction D2 of the first busbar portion 52. The second busbar portion 53, which has a narrow portion 535 with a smaller size in the first direction D1 compared to the size in the first direction D1 of the first busbar portion 52, has a greater thermal resistance compared to the first busbar portion 52.

[0148] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0149] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Consequently, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72. Then, it can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0150] Although this embodiment is a modification based on the first embodiment, it is possible to combine this embodiment with either the first or second embodiment.

[0151] (Fourth Embodiment) Next, the fourth embodiment will be described with reference to Figure 21. In this embodiment, the shape of the second busbar portion 53 differs from that of the third embodiment. Other than this, it is the same as the third embodiment. For this reason, in this embodiment, the parts that differ from the third embodiment will be mainly described, and the parts that are the same as the third embodiment may be omitted from the description.

[0152] As shown in Figure 21, the second busbar portion 53 of this embodiment has notches 536 formed at one end in the first direction D1 and at the other end in the first direction D1. Hereinafter, as shown in Figure 21, the notch 536 formed on one side in the first direction D1 will be called the first notch 5361, and the notch 536 formed on the other side in the first direction D1 will be called the second notch 5362.

[0153] The first notch 5361 is formed in the approximate center of the second busbar portion 53 in the second direction D2, and is formed by cutting out from one side of the first direction D1 to the other side. The first notch 5361 has a planar shape that extends in the second direction D2 when viewed along the third direction D3. The second notch 5362 is formed in the first direction D1 at a position that overlaps with the first notch 5361. The second notch 5362 has a planar shape that extends in the second direction D2 when viewed along the third direction D3. Furthermore, the second notch 5362 is formed in the approximate center of the second busbar portion 53 in the second direction D2, and is formed by cutting out from the other side of the first direction D1 to the one side.

[0154] In this embodiment, the second busbar portion 53 has a narrowed portion 535 formed between the first notch 5361 and the second notch 5362 as the first notch 5361 and the second notch 5362 are formed in this manner. The cross-sectional area of ​​the narrowed portion 535 perpendicular to the second direction D2 is smaller than the cross-sectional area of ​​the first busbar portion 52 perpendicular to the second direction D2. For this reason, the thermal resistance of the second busbar portion 53 in this embodiment is larger than that of the first busbar portion 52.

[0155] However, the shapes of the first notch 5361 and the second notch 5362 are not limited, and the planar shape when viewed in the direction along the third direction D3 can be a variety of shapes, such as a triangular shape or a semicircular shape. Also, two or more notches 536 may be formed on one side and the other side of the first direction D1. Furthermore, the second notch 5362 may be formed in a position that does not overlap with the first notch 5361 in the first direction D1.

[0156] The other configurations are the same as those of the third embodiment. The current detection device 1 of this embodiment can obtain the same effects as those of the third embodiment, which are achieved from a configuration that is the same as or equivalent to that of the third embodiment. Furthermore, although this embodiment is a modification based on the third embodiment, it is also possible to combine this embodiment with any one or more of the first to third embodiments described above.

[0157] (First Modification of the Fourth Embodiment) In the fourth embodiment described above, an example was described in which a first notch 5361 and a second notch 5362 are formed in the second busbar portion 53, but the invention is not limited thereto. For example, as shown in Figure 22, the second busbar portion 53 may be configured such that of the first notch 5361 and the second notch 5362, the second notch 5362 is not formed and only the first notch 5361 is formed. Alternatively, although not shown, the second busbar portion 53 may be configured such that of the first notch 5361 and the second notch 5362, the first notch 5361 is not formed and only the second notch 5362 is formed.

[0158] (Second Modification of the Fourth Embodiment) In the fourth embodiment described above, the dimensions of the first busbar portion 52 and the second busbar portion 53 are equal in the second direction D2, and an example was described in which a first notch 5361 and a second notch 5362 are formed in the second busbar portion 53. However, the invention is not limited to this. For example, as shown in Figure 23, similar to the first embodiment, the second busbar portion 53 may have a larger dimension in the second direction D2 compared to the dimension in the second direction D2 of the first busbar portion 52, and only the first notch 5361 may be formed. In this configuration, the thermal resistance of the second busbar portion 53 can be made greater than that of the first busbar portion 52 compared to the case where the dimensions of the second direction D2 of the first busbar portion 52 and the second busbar portion 53 are equal. Therefore, the part of the resistance portion 51 where the temperature is highest can be brought closer to the second busbar portion 53.

[0159] The specific temperature of the conductive busbar 50 will be explained with reference to Figure 24. When current flows through the conductive busbar 50, as shown in Figure 24, the temperature of the conductive busbar 50 becomes highest in the resistive section 51, the first busbar section 52, and the second busbar section 53. In addition, the temperature of the first busbar section 52 and the second busbar section 53 decreases as they move away from the resistive section 51.

[0160] Furthermore, in the resistor 51, the temperature on the side to which the second one-side end 533 is connected is higher than the temperature on the side to which the first one-side end 523 is connected. Therefore, the part of the resistor 51 that has the highest temperature can be located on the side of the second busbar 53 from the center of the third direction D3 in the resistor 51.

[0161] (Fifth Embodiment) Next, the fifth embodiment will be described with reference to Figure 25. In this embodiment, the shape of the second busbar portion 53 differs from that of the third embodiment. Other than this, it is the same as the third embodiment. For this reason, in this embodiment, the parts that differ from the third embodiment will be mainly described, and the parts that are the same as the third embodiment may be omitted from the description.

[0162] As shown in Figure 25, the second busbar portion 53 of this embodiment does not have a narrow portion 535. Furthermore, the second busbar portion 53 of this embodiment has one second busbar hole 537 formed through the second busbar portion 53 in the third direction D3. The second busbar hole 537 is formed closer to the second one-sided end 533 than the center in the second direction D2 of the second busbar portion 53. The planar shape of the second busbar hole 537, when viewed along the third direction D3, is rectangular.

[0163] In this embodiment, the second busbar portion 53 has a second busbar hole 537 formed in this manner, and as a result, the cross-sectional area perpendicular to the second direction D2 in the portion where the second busbar hole 537 is formed is smaller than the cross-sectional area perpendicular to the second direction D2 in the first busbar portion 52. For this reason, the thermal resistance of the second busbar portion 53 in this embodiment is greater than that of the first busbar portion 52.

[0164] However, the shape of the second busbar hole 537 is not limited, and the planar shape when viewed in the direction along the third direction D3 can be a variety of shapes, such as a triangular or circular shape. Also, the number of second busbar holes 537 is not limited, and two or more may be formed. The second busbar hole 537 corresponds to the second conductive through-hole formed through the second busbar portion 53 in the third direction D3.

[0165] The other configurations are the same as those of the third embodiment. The current detection device 1 of this embodiment can obtain the same effects as those of the third embodiment, which are achieved from a configuration that is the same as or equivalent to that of the third embodiment. Furthermore, although this embodiment is a modification based on the third embodiment, it is also possible to combine this embodiment with any one or more of the first to fourth embodiments described above.

[0166] (Sixth Embodiment) Next, the sixth embodiment will be described with reference to Figure 26. In this embodiment, the shape of the first busbar portion 52 differs from that of the fifth embodiment. Other than this, it is the same as the fifth embodiment. For this reason, in this embodiment, the parts that differ from the fifth embodiment will be mainly described, and the parts that are the same as the fifth embodiment may be omitted from the description.

[0167] As shown in Figure 26, the first busbar portion 52 of this embodiment has one first busbar hole 526 formed through the first busbar portion 52 in a third direction D3. The first busbar hole 526 is formed closer to the first one-sided end 523 than to the center in the second direction D2 of the first busbar portion 52. The planar shape of the first busbar hole 526 when viewed in the direction along the third direction D3 is rectangular. Furthermore, the size of the first busbar hole 526 when viewed in the direction along the third direction D3 is smaller than the size of the second busbar hole 537 when viewed in the direction along the third direction D3. Specifically, the size of the first busbar hole 526 in the first direction D1 is smaller than the size of the second busbar hole 537 in the first direction D1, and the size of the second busbar hole 526 in the second direction D2 is smaller than the size of the second busbar hole 537 in the second direction D2.

[0168] With this configuration, the cross-sectional area of ​​the second busbar portion 53 perpendicular to the second direction D2 in the portion where the second busbar hole 537 is formed is smaller than the cross-sectional area of ​​the first busbar portion 52 perpendicular to the second direction D2 in the portion where the first busbar hole 526 is formed. For this reason, the thermal resistance of the second busbar portion 53 in this embodiment is greater than that of the first busbar portion 52.

[0169] However, the shape of the first busbar hole 526 is not limited to this, as long as the cross-sectional area of ​​the portion where the second busbar hole 537 is formed, perpendicular to the second direction D2, is smaller than the cross-sectional area of ​​the portion where the first busbar hole 526 is formed. For example, the shape of the first busbar hole 526 can be various shapes, such as a triangular or circular shape, when viewed in the direction along the third direction D3. Also, the number of first busbar holes 526 is not limited, and two or more may be formed. The first busbar hole 526 corresponds to the first conductive through-hole formed through the first busbar portion 52 in the third direction D3.

[0170] The other configurations are the same as those of the fifth embodiment. The current detection device 1 of this embodiment can obtain the same effects and advantages as those of the fifth embodiment, which are achieved from a configuration that is the same as or equivalent to that of the fifth embodiment. Furthermore, although this embodiment is a modification based on the fifth embodiment, it is also possible to combine this embodiment with any one or more of the first to fifth embodiments described above.

[0171] (Seventh Embodiment) Next, the seventh embodiment will be described with reference to Figure 27. In this embodiment, the shapes of the first busbar portion 52 and the second busbar portion 53 differ from those of the third embodiment. Other than this, it is the same as the third embodiment. For this reason, in this embodiment, the parts that differ from the third embodiment will be mainly described, and the parts that are the same as the third embodiment may be omitted from the description.

[0172] The second busbar portion 53 of this embodiment does not have a narrow portion 535. Also, as shown in Figure 27, the first busbar portion 52 of this embodiment has a larger size in the third direction D3 compared to the second busbar portion 53. Specifically, the size of the first busbar portion 52 in the third direction D3 is larger than that of the second busbar portion 53 from the first one-sided end 523 to the first other-sided end 524. The first busbar portion 52 is formed with a constant size in the third direction D3 from the first one-sided end 523 to the first other-sided end 524, and the plate surface on the other side of the third direction D3 protrudes to the other side of the third direction D3 from the plate surface on the other side of the third direction D3 of the second busbar portion 53. Also, the first busbar portion 52 is formed with a constant size in the third direction D3 from one end to the other end of the first direction D1.

[0173] The first busbar portion 52 formed in this manner has a larger cross-sectional area perpendicular to the second direction D2 compared to the cross-sectional area perpendicular to the second direction D2 of the second busbar portion 53. The portion of the first busbar portion 52 that is larger in the third direction D3 compared to the second busbar portion 53 is designated as the thickened portion 525, and the first busbar portion 52 in this embodiment is entirely composed of the thickened portion 525. For this reason, the thermal resistance of the first busbar portion 52 in this embodiment is smaller compared to the second busbar portion 53.

[0174] However, the shape of the first busbar portion 52 is not limited, and various shapes can be adopted as long as it has a thickened portion 525. For example, the first busbar portion 52 may be formed so that only a part of it is larger than the size of the third direction D3 of the other part, and a part of the first busbar portion 52 may be composed of a thickened portion 525. In this case, the first busbar portion 52 may have multiple thickened portions 525. Also, the size of the thickened portion 525 may be constant from one end to the other end in the second direction D2, or it may be inclined instead of constant. Furthermore, the size of the thickened portion 525 may be constant from one end to the other end in the first direction D1, or it may be inclined instead of constant. Also, the thickened portion 525 may be formed so that one side of the plate surface in the third direction D3 protrudes to one side of the third direction D3 from one side of the plate surface in the third direction D3 of the second busbar portion 53. Furthermore, the thickened portion 525 can take on various shapes, such as rectangular, triangular, or circular, when viewed along the first direction D1.

[0175] The first busbar portion 52 and the second busbar portion 53 of this embodiment, formed in this manner, have a non-symmetrical shape with respect to the axis of symmetry SL. Furthermore, the first busbar portion 52, which is composed of a thicker portion 525 whose size in the third direction D3 is larger than that of the second busbar portion 53, has a lower thermal resistance compared to the second busbar portion 53. In other words, the second busbar portion 53 of this embodiment has a higher thermal resistance compared to the first busbar portion 52.

[0176] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0177] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Consequently, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72. Then, it can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0178] Although this embodiment is a modification based on the third embodiment, it is also possible to combine this embodiment with any one or more of the first to fifth embodiments described above.

[0179] (Eighth Embodiment) Next, the eighth embodiment will be described with reference to Figures 28 and 29. In this embodiment, the shape of the second busbar portion 53 differs from that of the third embodiment. Other than this, it is the same as the third embodiment. For this reason, in this embodiment, the parts that differ from the third embodiment will be mainly described, and the parts that are the same as the third embodiment may be omitted from the description.

[0180] As shown in Figures 28 and 29, the second busbar portion 53 of this embodiment does not have a narrow portion 535. Furthermore, the second busbar portion 53 of this embodiment has a thin portion 538 in which the size in the third direction D3 is smaller compared to the size in the third direction D3 of other parts. The thin portion 538 has a smaller size in the third direction D3 compared to other parts of the second busbar portion 53. Also, the thin portion 538 has a smaller size in the third direction D3 compared to the size in the third direction D3 of the first busbar portion 52. For this reason, the size in the third direction D3 of the second busbar portion 53 of this embodiment is not constant from the second one-sided end 533 to the second other-sided end 534.

[0181] In this embodiment, the thin portion 538 is formed by creating a recessed portion 5381 in which a part of the second busbar surface 532 is recessed in the third direction D3. The recessed portion 5381 is formed in the approximate central part of the second busbar portion 53 in the second direction D2, and is formed in a groove shape that is recessed along the first direction D1 from one end to the other end in the first direction D1. The recessed portion 5381 is formed in a triangular prism shape extending in the first direction D1, and has a planar shape when viewed along the third direction D3.

[0182] However, the shape of the thin portion 538 is not limited, and various shapes can be adopted, such as a rectangular prism or a semi-cylindrical shape extending in the first direction D1. Furthermore, the thin portion 538 may be formed as a recess along the second direction D2, or as a recess along a direction intersecting the first direction D1 and the second direction D2. Also, the thin portion 538 may be formed on the side of the second busbar portion 53 opposite to the second busbar surface 532. Moreover, multiple thin portions 538 may be formed, in which case they may be formed only on the second busbar surface 532 and the side opposite to the second busbar surface 532, or they may be formed on either the second busbar surface 532 and the side opposite to the second busbar surface 532.

[0183] The first busbar portion 52 and the second busbar portion 53 of this embodiment, formed in this manner, have a non-symmetric shape with respect to the axis of symmetry SL. Furthermore, the cross-sectional area of ​​the portion of the second busbar portion 53 in the area where the thin portion 538 is formed, perpendicular to the second direction D2, is smaller than that of the first busbar portion 52 in the same direction D2. The second busbar portion 53, having a thin portion 538 in which the size of the third direction D3 is smaller than that of the first busbar portion 52, has a greater thermal resistance than the first busbar portion 52.

[0184] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0185] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Consequently, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72. Then, it can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0186] Although this embodiment is a modification based on the third embodiment, it is also possible to combine this embodiment with any one or more of the first to seventh embodiments described above.

[0187] (Ninth Embodiment) Next, the ninth embodiment will be described with reference to Figure 30. In this embodiment, the shapes of the first busbar portion 52 and the second busbar portion 53 differ from those of the first embodiment, and the first busbar portion 52 and the second busbar portion 53 are formed from different materials. Other than this, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0188] As shown in Figure 30, the first busbar section 52 and the second busbar section 53 of this embodiment have equal magnitudes in the second direction D2. Furthermore, the first busbar section 52 and the second busbar section 53 of this embodiment are formed from different materials. Specifically, in this embodiment, for example, if the first busbar section 52 is made of copper, the second busbar section 53 is made of a material with a higher thermal conductivity than copper, such as aluminum. As a result, the thermal resistance per unit volume of the second busbar section 53 of this embodiment is greater than that per unit volume of the first busbar section 52.

[0189] The materials of the first busbar section 52 and the second busbar section 53 are not limited to those shown. The first busbar section 52 may be made of a material other than copper, provided that the thermal conductivity of the second busbar section 53 is greater than that of the first busbar section 52. Similarly, the second busbar section 53 may be made of a material other than aluminum, provided that the thermal conductivity of the second busbar section 53 is greater than that of the first busbar section 52. In Figure 30, different hatching is applied to the first busbar section 52 and the second busbar section 53 to clearly show that they are made of different materials.

[0190] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0191] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Consequently, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals obtained from the first thermistor 71 and the second thermistor 72. Then, it can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0192] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any one of the first to eighth embodiments described above, or with multiple embodiments.

[0193] (Tenth Embodiment) Next, the tenth embodiment will be described with reference to Figure 31. In this embodiment, the shapes of the first busbar portion 52 and the second busbar portion 53 differ from those of the first embodiment, and the shape of the battery connection portion VT1 to which the first busbar portion 52 is fixed also differs from that of the first embodiment. Other than these differences, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0194] As shown in Figure 31, the first busbar section 52 and the second busbar section 53 of this embodiment have equal magnitudes in the second direction D2. Specifically, the first busbar section 52 has a larger magnitude in the second direction D2 compared to the first busbar section 52 of the first embodiment. Also, the second busbar section 53 has a smaller magnitude in the second direction D2 compared to the second busbar section 53 of the first embodiment. As a result, the first busbar length L1 and the second busbar length L2 are equal. Furthermore, the first busbar section 52 and the second busbar section 53 have shapes that are symmetrical with respect to the axis of symmetry SL. In addition, the first busbar section 52 and the second busbar section 53 are made of the same material and have approximately equal thermal resistance per unit volume. For this reason, the first busbar section 52 and the second busbar section 53 have approximately equal thermal resistance.

[0195] Furthermore, the distance from the first other end 524 to the first connection hole 521 is approximately equal to the distance from the second other end 534 to the second connection hole 531. And the distance from the first one end 523 to the first connection hole 521 is approximately equal to the distance from the second one end 533 to the second connection hole 531. That is, the distance from the resistance portion 51 to the first connection hole 521 in the second direction D2 is approximately equal to the distance from the resistance portion 51 to the second connection hole 531 in the second direction D2. And the distance from the target axis SL to the center CL1 of the first hole and the distance from the target axis SL to the center CL2 of the second hole are approximately equal to each other. And the inner diameters of the first connection hole 521 and the second connection hole 531 are approximately equal to each other.

[0196] Furthermore, as shown in Figure 31, the size of the first direction D1 of the battery connection part VT1 to which the first busbar part 52 of the battery VT is fixed is different from the size of the first direction D1 of the busbar connection part BU1 to which the second busbar part 53 of the energized busbar BU is fixed. Specifically, the size of the first direction D1 of the busbar connection part BU1 is smaller than the size of the first direction D1 of the battery connection part VT1. In other words, the busbar connection part BU1 has a narrow shape in which the size of the first direction D1 is larger than the size of the first direction D1 of the battery connection part VT1.

[0197] When the battery connection part VT1 and the busbar connection part BU1 are formed in this manner, the electrical resistance of the part of the energized busbar BU to which the conductive busbar 50 is connected is greater than the electrical resistance of the part of the battery VT to which the conductive busbar 50 is connected. That is, when current flows through the energized busbar BU, the electrical resistance of the connection part for allowing current to flow from the conductive busbar 50 to the energized busbar BU is greater than the electrical resistance of the connection part for allowing current to flow from the battery VT to the energized busbar BU.

[0198] Therefore, when current flows from the battery VT to the energized busbar BU via the conductive busbar 50, the temperature of the conductive busbar 50 rises due to the flow of current, and the temperature of the second busbar section 53 rises more easily than that of the first busbar section 52. For this reason, a temperature difference can be generated between the first busbar section 52 and the second busbar section 53 when current flows through the conductive busbar 50. The temperature of the second busbar section 53 can be made higher than that of the first busbar section 52. For this reason, the battery management system VMS of this embodiment can provide a temperature difference between the first busbar section 52 and the second busbar section 53 regardless of the configuration of the conductive busbar 50 in the current detection device 1.

[0199] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0200] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Accordingly, in this embodiment, the battery management system VMS can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals acquired from the first thermistor 71 and the second thermistor 72 by the third sensing unit 25. Then, the battery management system VMS can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0201] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any one or more of the first to ninth embodiments described above.

[0202] (Modification of the 10th Embodiment) In the 10th embodiment described above, an example was described in which the size of the busbar connection portion BU1 in the first direction D1 is larger than the size of the battery connection portion VT1 in the first direction D1, but the invention is not limited to this. As long as the electrical resistance of the connection portion between the conductive busbar 50 and the busbar connection portion BU1 is greater than the electrical resistance of the connection portion between the battery connection portion VT1 and the conductive busbar 50, the energized busbar BU and the battery VT can take on various shapes. For example, as shown in Figure 32, the busbar connection portion BU1 may have a shape in which the size of the third direction D3 is smaller than the size of the battery connection portion VT1 in the third direction D3. In other words, the busbar connection portion BU1 may have a thickness that is smaller than the size of the battery connection portion VT1 in the third direction D3. Alternatively, although not shown in the figures, the busbar connection portion BU1 may have a narrow width, where the size in the first direction D1 is smaller than the size in the first direction D1 of the battery connection portion VT1, and a thin thickness, where the size in the third direction D3 is smaller than the size in the third direction D3 of the battery connection portion VT1.

[0203] (Perspectives of this Disclosure) As will be apparent from the description of the embodiments above, the disclosures herein include at least the following perspectives:

[0204] [Perspective 1] A circuit system having a conductive path forming unit that forms a conductive path through which electric current flows, comprising a current detection device (1) for detecting the current flowing through the conductive path, wherein the current detection device comprises: a flat conductive member (50) with one direction of extension as the extension direction through which electric current flows; a temperature detection unit (71, 72) that outputs a temperature detection signal corresponding to the temperature of the conductive member; a resistance correction unit (25) that corrects the electrical resistance value of the conductive member based on the temperature detection signal; a current detection unit (25) that outputs a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value corrected by the resistance correction unit and the voltage applied to the conductive member; and a connection unit (60) that connects the conductive member to the temperature detection unit and the current detection unit. The conductive member includes a resistive portion (51), a first conductive portion (52) having lower electrical resistance than the resistive portion and provided on one side of the resistive portion in the extension direction, and a second conductive portion (53) having lower electrical resistance than the resistive portion and provided on the other side of the resistive portion in the extension direction; the connection portion includes a first connection portion (61) connected to the first conductive portion and a second connection portion (62) connected to the second conductive portion; the temperature detection portion is positioned at a location where its distance from the second connection portion is smaller than its distance from the first connection portion; the conductive path forming portion includes a first forming portion (VT) connected to the first conductive portion through which current flows, and a second forming portion (BU) connected to the second conductive portion through which current flows; A circuit system in which the second formed portion has at least one of the following shapes: a narrow shape in which the size in the thickness direction is greater than the size in the thickness direction of the first formed portion, and a narrow shape in which the size in the width direction is greater than the size in the width direction of the first formed portion, when the width direction of the conductive member is defined as the width direction.

[0205] (Eleventh Embodiment) Next, the eleventh embodiment will be described with reference to Figures 33 and 34. In this embodiment, the shapes of the first busbar section 52 and the second busbar section 53 differ from those of the first embodiment, and the shape of the first bolt B1 for connecting the second busbar section 53 to the energized busbar BU also differs from that of the first embodiment. Other than these differences, it is the same as the first embodiment. For this reason, in this embodiment, we will mainly describe the parts that differ from the first embodiment, and we may omit the description of parts that are the same as the first embodiment.

[0206] As shown in Figures 33 and 34, the first busbar section 52 and the second busbar section 53 of this embodiment have equal magnitudes in the second direction D2. Specifically, the first busbar section 52 has a larger magnitude in the second direction D2 compared to the first busbar section 52 of the first embodiment. Also, the second busbar section 53 has a smaller magnitude in the second direction D2 compared to the second busbar section 53 of the first embodiment. As a result, the first busbar length L1 and the second busbar length L2 are equal. Furthermore, the first busbar section 52 and the second busbar section 53 have shapes that are symmetrical with respect to the axis of symmetry SL. In addition, the first busbar section 52 and the second busbar section 53 are made of the same material and have approximately equal thermal resistance per unit volume. For this reason, the first busbar section 52 and the second busbar section 53 have approximately equal thermal resistance.

[0207] Furthermore, the distance from the first other end 524 to the first connection hole 521 is approximately equal to the distance from the second other end 534 to the second connection hole 531. And the distance from the first one end 523 to the first connection hole 521 is approximately equal to the distance from the second one end 533 to the second connection hole 531. In other words, the distance from the resistance portion 51 to the first connection hole 521 in the second direction D2 is approximately equal to the distance from the resistance portion 51 to the second connection hole 531 in the second direction D2. And the distance from the target axis SL to the center CL1 of the first hole and the distance from the target axis SL to the center CL2 of the second hole are approximately equal to each other.

[0208] Furthermore, as shown in Figures 33 and 34, the inner diameter of the first connection hole 521 in this embodiment is larger than that of the first connection hole 521 in the first embodiment. As a result, the inner diameter of the first connection hole 521 is larger than that of the second connection hole 531. For example, if the inner diameter of the second connection hole 531 is set to 6.5 mm, the inner diameter of the first connection hole 521 can be set to 7.5 mm or 8.5 mm, etc. However, the inner diameters of the first connection hole 521 and the second connection hole 531 are not limited.

[0209] Furthermore, as shown in Figures 33 and 34, the first bolt B1 of this embodiment has a larger bolt size than the first bolt B1 of the first embodiment. Specifically, the first bolt B1 has a first head B11 and a first shaft B12, and the cross-sectional area of ​​the first head B11 perpendicular to the third direction D3 is larger than that of the first bolt B1 of the first embodiment, and the outer diameter of the first shaft B12 is larger than that of the first bolt B1 of the first embodiment. Also, the cross-sectional area of ​​the first head B11 perpendicular to the third direction D3 is larger than that of the second head B21 of the second bolt B2 perpendicular to the third direction D3, and the outer diameter of the first shaft B12 is larger than that of the second shaft B22 of the second bolt B2. For this reason, in this embodiment, the conductive busbar 50 has the first busbar portion 52 fastened by the first bolt B1, which has a larger bolt size than the second bolt B2 to which the second busbar portion 53 is fastened.

[0210] In this configuration, the contact area between the first head B11 of the first bolt B1 and the first busbar surface 522 of the first busbar portion 52 is larger than the contact area between the first head B11 of the first bolt B1 and the first busbar surface 522 of the first busbar portion 52 in the first embodiment. Furthermore, the contact area between the first bolt B1 and the first busbar surface 522 in this embodiment is larger than the contact area between the second bolt B2 and the second busbar surface 532 in this embodiment.

[0211] Furthermore, the contact area between the outer circumferential surface of the first shaft portion B12 and the inner circumferential surface of the first connection hole 521 is larger than the contact area between the outer circumferential surface of the first shaft portion B12 and the inner circumferential surface of the first connection hole 521 in the first embodiment. Also, the contact area between the first bolt B1 and the inner circumferential surface of the first connection hole 521 in this embodiment is larger than the contact area between the second bolt B2 and the inner circumferential surface of the second connection hole 531 in this embodiment. As a result, the contact area between the second bolt B2 and the second busbar portion 53 is smaller than the contact area between the first bolt B1 and the first busbar portion 52.

[0212] Incidentally, the contact resistance between the first bolt B1 and the first busbar portion 52 decreases as the contact area between the first bolt B1 and the first busbar portion 52 increases, and increases as the contact area between the first bolt B1 and the first busbar portion 52 decreases. Also, the contact resistance between the second bolt B2 and the second busbar portion 53 decreases as the contact area between the second bolt B2 and the second busbar portion 53 increases, and increases as the contact area between the second bolt B2 and the second busbar portion 53 decreases. For this reason, if the contact area between the first bolt B1 and the first busbar portion 52 is larger than the contact area between the second bolt B2 and the second busbar portion 53, the contact resistance between the first bolt B1 and the first busbar portion 52 will be smaller than the contact resistance between the second bolt B2 and the second busbar portion 53.

[0213] Furthermore, the electrical resistance at the point where the first bolt B1 and the first busbar portion 52 are fastened decreases as the contact resistance between the first bolt B1 and the first busbar portion 52 decreases, and increases as the contact resistance between the first bolt B1 and the first busbar portion 52 increases. Similarly, the electrical resistance at the point where the second bolt B2 and the second busbar portion 53 are fastened decreases as the contact resistance between the second bolt B2 and the second busbar portion 53 decreases, and increases as the contact resistance between the second bolt B2 and the second busbar portion 53 increases.

[0214] In this embodiment, the contact resistance between the first bolt B1 and the first busbar portion 52 is smaller than the contact resistance between the second bolt B2 and the second busbar portion 53. Therefore, the electrical resistance at the point where the first bolt B1 and the first busbar portion 52 are fastened is smaller than the electrical resistance at the point where the second bolt B2 and the second busbar portion 53 are fastened. In other words, if the contact area between the first bolt B1 and the first busbar portion 52 is larger than the contact area between the second bolt B2 and the second busbar portion 53, the electrical resistance at the point fastened by the second bolt B2 will be larger than the electrical resistance at the point fastened by the first bolt B1.

[0215] Therefore, when current flows from the battery VT to the energized busbar BU via the conductive busbar 50, the temperature of the conductive busbar 50 rises due to the flow of current, and the temperature of the second busbar section 53 rises more easily than that of the first busbar section 52. For this reason, a temperature difference can be generated between the first busbar section 52 and the second busbar section 53 when current flows through the conductive busbar 50. The temperature of the second busbar section 53 can be made higher than that of the first busbar section 52. For this reason, the battery management system VMS of this embodiment can provide a temperature difference between the first busbar section 52 and the second busbar section 53 regardless of the configuration of the conductive busbar 50 in the current detection device 1.

[0216] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0217] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Accordingly, in this embodiment, the battery management system VMS can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals acquired from the first thermistor 71 and the second thermistor 72 by the third sensing unit 25. Then, the battery management system VMS can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0218] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any of the first to tenth embodiments described above.

[0219] (Modification of the 11th Embodiment) In the 11th embodiment described above, the contact area between the second bolt B2 and the second busbar portion 53 is smaller than the contact area between the first bolt B1 and the first busbar portion 52. As a result, a configuration has been described in which the electrical resistance at the point where the first bolt B1 and the first busbar portion 52 are fastened is smaller than the electrical resistance at the point where the second bolt B2 and the second busbar portion 53 are fastened. However, the configuration is not limited to this, as long as the electrical resistance at the point where the first bolt B1 and the first busbar portion 52 are fastened is smaller than the electrical resistance at the point where the second bolt B2 and the second busbar portion 53 are fastened.

[0220] The contact resistance between the first bolt B1 and the first busbar portion 52 decreases as the fastening force is greater when the first busbar portion 52 and the battery VT are clamped between the first bolt B1 and the first nut N1 and the first nut N1 is fastened, and increases as the fastening force decreases. Therefore, the electrical resistance at the point where the first bolt B1 and the first busbar portion 52 are fastened decreases as the fastening force is greater when the first bolt B1 and the first nut N1 are fastened, and increases as the fastening force decreases.

[0221] Furthermore, the contact resistance between the second bolt B2 and the second busbar portion 53 decreases as the fastening force is greater when the second busbar portion 53 and the energized busbar BU are clamped between the second bolt B2 and the second nut N2 and the second nut N2 is fastened, and increases as the fastening force decreases. For this reason, the electrical resistance at the point where the second bolt B2 and the second busbar portion 53 are fastened decreases as the fastening force is greater when the second bolt B2 and the second nut N2 are fastened, and increases as the fastening force decreases.

[0222] Therefore, the fastening force when fastening the first bolt B1 and the first nut N1, sandwiching the first busbar portion 52 and the battery VT, may be greater than the fastening force when fastening the second bolt B2 and the second nut N2, sandwiching the second busbar portion 53 and the energized busbar BU. In other words, the fastening force when fastening the second busbar portion 53 may be less than the fastening force when fastening the first busbar portion 52. This makes it possible to make the electrical resistance of the area where the second bolt B2 and the second busbar portion 53 are fastened greater than the electrical resistance of the area where the first bolt B1 and the first busbar portion 52 are fastened. In this case, the first bolt B1 and the second bolt B2 may have the same bolt size. Also, the first connection hole 521 and the second connection hole 531 may have the same inner diameter.

[0223] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0224] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Consequently, the third sensing unit 25 can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals acquired from the first thermistor 71 and the second thermistor 72, and accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0225] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any one of the aforementioned first embodiment, third embodiment to tenth embodiment, or multiple embodiments.

[0226] (Perspectives of this Disclosure) As will be apparent from the description of the embodiments above, the disclosures herein include at least the following perspectives:

[0227] [Perspective 2-1] A circuit system having a conductive path forming section that forms a conductive path through which electric current flows, comprising a current detection device (1) for detecting the current flowing through the conductive path, wherein the current detection device comprises: a flat conductive member (50) with one direction of extension as the extension direction through which electric current flows; a temperature detection section (71, 72) that outputs a temperature detection signal corresponding to the temperature of the conductive member; a resistance correction section (25) that corrects the electrical resistance value of the conductive member based on the temperature detection signal; a current detection section (25) that outputs a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value corrected by the resistance correction section and the voltage applied to the conductive member; and a connection section (60) that connects the conductive member to the temperature detection section and the current detection section. The conductive member includes a resistive portion (51), a first conductive portion (52) having lower electrical resistance than the resistive portion and provided on one side of the resistive portion in the extension direction, and a second conductive portion (53) having lower electrical resistance than the resistive portion and provided on the other side of the resistive portion in the extension direction; the connection portion includes a first connection portion (61) connected to the first conductive portion and a second connection portion (62) connected to the second conductive portion; the temperature detection portion is positioned such that its distance from the second connection portion is smaller than its distance from the first connection portion; the conductive path forming portion includes a first forming portion (V) connected to the first conductive portion and a second forming portion (BU) connected to the second conductive portion; the first conductive portion has a first connection hole (521) into which a first fastening member for attaching the first conductive portion to the first forming portion is inserted. The circuit system wherein the second conductive portion has a second connection hole (531) into which a second fastening member for attaching the second conductive portion to the second forming portion is inserted, and the contact resistance when the first conductive portion and the first forming portion are fastened by the first fastening member is smaller than the contact resistance when the second conductive portion and the second forming portion are fastened by the second fastening member.

[0228] [Perspective 2-2] The circuit system according to Perspective 2-1, wherein the contact area of ​​the portion where the first conductive portion and the first fastening member contact is greater than the contact area of ​​the portion where the second conductive portion and the second fastening member contact. [Perspective 2-3] The circuit system according to Perspective 2-1, wherein the fastening force that fastens the first conductive portion and the first forming portion by the first fastening member is greater than the fastening force that fastens the second conductive portion and the second forming portion by the second fastening member.

[0229] (Twelfth Embodiment) Next, the twelfth embodiment will be described with reference to Figures 35 and 36. In this embodiment, the shapes of the first busbar section 52 and the second busbar section 53 differ from those of the first embodiment, and the battery management system VMS is equipped with a cooling device CD, which is another difference from the first embodiment. Other than these differences, it is the same as the first embodiment. For this reason, in this embodiment, we will mainly describe the parts that differ from the first embodiment, and we may omit the description of parts that are the same as the first embodiment.

[0230] As shown in Figure 35, the first busbar section 52 and the second busbar section 53 of this embodiment have equal dimensions in the second direction D2. Specifically, the first busbar section 52 has a larger dimension in the second direction D2 compared to the first busbar section 52 of the first embodiment. Also, the second busbar section 53 has a smaller dimension in the second direction D2 compared to the second busbar section 53 of the first embodiment. As a result, the first busbar length L1 and the second busbar length L2 are equal. Furthermore, the first busbar section 52 and the second busbar section 53 have shapes that are symmetrical with respect to the axis of symmetry SL. In addition, the first busbar section 52 and the second busbar section 53 are made of the same material and have approximately equal thermal resistance per unit volume. For this reason, the first busbar section 52 and the second busbar section 53 have approximately equal thermal resistance.

[0231] Furthermore, the distance from the first other end 524 to the first connection hole 521 is approximately equal to the distance from the second other end 534 to the second connection hole 531. And the distance from the first one end 523 to the first connection hole 521 is approximately equal to the distance from the second one end 533 to the second connection hole 531. That is, the distance from the resistance portion 51 to the first connection hole 521 in the second direction D2 is approximately equal to the distance from the resistance portion 51 to the second connection hole 531 in the second direction D2. And the distance from the target axis SL to the center CL1 of the first hole and the distance from the target axis SL to the center CL2 of the second hole are approximately equal to each other. And the inner diameters of the first connection hole 521 and the second connection hole 531 are approximately equal to each other.

[0232] Furthermore, as shown in Figure 36, the battery management system VMS of this embodiment includes a battery VT, a system main relay SMR, a battery ECU 200, and a current detection device 1, in addition to a cooling device CD. The cooling device CD is a cooler that cools the battery VT. Specifically, the cooling device CD is connected to a refrigerant circuit (not shown) that circulates a refrigerant, and is an evaporator that evaporates the refrigerant to exert an endothermic effect.

[0233] The cooling device CD is connected to the battery VT by a water circuit that circulates cooling water, and the cooling water circulates between the cooling device CD and the battery VT. The cooling device CD then cools the battery VT by exchanging heat between the cooling water heated by the battery VT and the refrigerant, thereby cooling the cooling water.

[0234] In this battery management system VMS equipped with a cooling device CD, the battery VT can be cooled by the cooling device CD. When the battery VT is cooled and the temperature of the battery connection portion VT1 of the battery VT is lower than the temperature of the conductive busbar 50, the conductive busbar 50, which is mechanically connected to the battery VT, is cooled by contacting the battery connection portion VT1 of the battery VT. In this embodiment of the battery management system VMS, where the battery connection portion VT1 and the first busbar portion 52 are connected, the first busbar portion 52 is indirectly connected to the cooling device CD. Therefore, for example, if the temperature of the first busbar portion 52 is higher than the temperature of the battery connection portion VT1, the first busbar portion 52 can be indirectly cooled by the cooling device CD.

[0235] Therefore, when current flows from the battery VT to the energized busbar BU via the conductive busbar 50, the temperature of the conductive busbar 50 rises due to the flow of current, but the temperature of the first busbar section 52 rises less easily compared to the second busbar section 53. Consequently, when current flows through the conductive busbar 50, a temperature difference can be generated between the first busbar section 52 and the second busbar section 53. This makes it possible to raise the temperature of the second busbar section 53 higher than the temperature of the first busbar section 52. For this reason, the battery management system VMS of this embodiment can provide a temperature difference between the first busbar section 52 and the second busbar section 53 regardless of the configuration of the conductive busbar 50 in the current detection device 1.

[0236] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0237] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Accordingly, in this embodiment, the battery management system VMS can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals acquired from the first thermistor 71 and the second thermistor 72 by the third sensing unit 25. Then, the battery management system VMS can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0238] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with any one of the first to eleventh embodiments described above, or with multiple embodiments.

[0239] (Modification of the 12th Embodiment) In the 12th embodiment described above, an example was described in which a temperature difference is generated between the first busbar section 52 and the second busbar section 53 by indirectly cooling the first busbar section 52 with a cooling device CD, but the invention is not limited to this. In the battery management system VMS of this embodiment, the second busbar section 53 is connected to the energized busbar BU, and the energized busbar BU is connected to the system main relay SMR which has three relays RL. The three relays RL are heat-generating devices that generate heat through their switching operation. That is, the second busbar section 53 is indirectly connected to the heat-generating devices RL via the energized busbar BU. In this case, for example, if the temperature of the second busbar section 53 is lower than the temperature of the busbar connection section BU1, the second busbar section 53 can be indirectly heated by the relays RL.

[0240] Therefore, when current flows from the battery VT to the energized busbar BU via the conductive busbar 50, the temperature of the conductive busbar 50 rises due to the flow of current, and the temperature of the second busbar section 53 rises more easily than that of the first busbar section 52. Consequently, when current flows through the conductive busbar 50, a temperature difference can be generated between the first busbar section 52 and the second busbar section 53. This makes it possible to raise the temperature of the second busbar section 53 higher than that of the first busbar section 52. For this reason, the battery management system VMS of this embodiment can provide a temperature difference between the first busbar section 52 and the second busbar section 53 regardless of the configuration of the conductive busbar 50 in the current detection device 1.

[0241] According to this, when current flows through the conductive busbar 50, the part of the resistive section 51 where the temperature is highest is the part on the second busbar section 53 side rather than the center in the second direction D2. Furthermore, the temperature difference between the highest temperature in the resistive section 51 and the temperature of the second busbar section 53 is smaller than the temperature difference between the highest temperature in the resistive section 51 and the temperature of the first busbar section 52.

[0242] Therefore, the temperature difference between the temperature detected by the first thermistor 71 and the second thermistor 72 when detecting the temperature of the resistor 51 via the second connection pin 62 connected to the second busbar 53 can be suppressed. Accordingly, in this embodiment, the battery management system VMS can accurately correct the electrical resistance value of the resistor 51 based on the temperature detection signals acquired from the first thermistor 71 and the second thermistor 72 by the third sensing unit 25. Then, the battery management system VMS can accurately detect the current value based on the corrected electrical resistance value of the resistor 51.

[0243] (Perspectives of this Disclosure) As will be apparent from the description of the embodiments above, the disclosures herein include at least the following perspectives:

[0244] [Perspective 3] A temperature control system for managing the temperature of a controlled object (VT) placed in a conductive path formation that forms a conductive path through which electric current flows, comprising: a current detection device (1) for detecting the current flowing through the conductive path; and a cooling device (CD) for cooling the controlled object, wherein the current detection device comprises: a flat conductive member (50) with one direction of extension as the extension direction through which electric current flows; a temperature detection unit (71, 72) for outputting a temperature detection signal corresponding to the temperature of the conductive member; a resistance correction unit (25) for correcting the electrical resistance value of the conductive member based on the temperature detection signal; a current detection unit (25) for outputting a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value corrected by the resistance correction unit and the voltage applied to the conductive member; and a connection unit (60) for connecting the conductive member to the temperature detection unit and the current detection unit. The conductive member includes a resistive portion (51), a first conductive portion (52) having lower electrical resistance than the resistive portion and provided on one side of the resistive portion in the extension direction, and a second conductive portion (53) having lower electrical resistance than the resistive portion and provided on the other side of the resistive portion in the extension direction; the connection portion includes a first connection portion (61) connected to the first conductive portion and a second connection portion (62) connected to the second conductive portion; the temperature detection unit is positioned such that its distance from the second connection portion is smaller than its distance from the first connection portion; and the first conductive portion is connected to the cooling device.

[0245] [Perspective 4] A temperature control system for managing the temperature of a controlled object (V) placed in a conductive path formation that forms a conductive path through which electric current flows, comprising: a current detection device (1) for detecting the current flowing through the conductive path; and a heating device (RL) that generates heat upon operation, wherein the current detection device comprises: a flat conductive member (50) with one direction of extension as the extension direction through which electric current flows; a temperature detection unit (71, 72) for outputting a temperature detection signal corresponding to the temperature of the conductive member; a resistance correction unit (25) for correcting the electrical resistance value of the conductive member based on the temperature detection signal; a current detection unit (25) for outputting a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value corrected by the resistance correction unit and the voltage applied to the conductive member; and a connection unit (60) for connecting the conductive member to the temperature detection unit and the current detection unit. The conductive member includes a resistive portion (51), a first conductive portion (52) having lower electrical resistance than the resistive portion and provided on one side of the resistive portion in the extension direction, and a second conductive portion (53) having lower electrical resistance than the resistive portion and provided on the other side of the resistive portion in the extension direction; the connection portion includes a first connection portion (61) connected to the first conductive portion and a second connection portion (62) connected to the second conductive portion; the temperature detection unit is positioned such that its distance from the second connection portion is smaller than its distance from the first connection portion; and the second conductive portion is connected to the heating device, wherein the temperature control system is configured as follows:

[0246] (Third Embodiment) Next, the thirteenth embodiment will be described with reference to Figures 37 to 43. In this embodiment, the shape of the first busbar portion 52 differs from that of the first embodiment. Also, in this embodiment, the battery VT and the conductive busbar 50 are connected to one side of the conductive busbar 50 in the third direction D3, which differs from the first embodiment. Other than this, it is the same as the first embodiment. For this reason, in this embodiment, the parts that differ from the first embodiment will be mainly described, and the parts that are the same as the first embodiment may be omitted from the description.

[0247] As shown in Figure 37, in this embodiment, the conductive busbar 50 is connected to the battery VT and the conductive busbar 50 on one side of the plate surface in the third direction D3. Specifically, the conductive busbar 50 is connected by the battery connection surface VT2 of the battery connection part VT1 contacting the first busbar surface 522 of the first busbar part 52, and by the busbar connection surface BU2 of the busbar connection part BU1 contacting the second busbar surface 532 of the second busbar part 53. More specifically, the battery connection part VT1 is connected to the first busbar part 52 by inserting the first bolt B1 into the first connection hole 521 formed on one side of the second direction D2 from the part to which the first connection pin 61 is connected. The busbar connection part BU1 is connected to the second busbar part 53 by inserting the second bolt B2 into the second connection hole 531 formed on the other side of the second direction D2 from the part to which the second connection pin 62 is connected.

[0248] The first busbar surface 522 of the first busbar portion 52 corresponds to a first mounting contact surface that abuts against the battery connection surface VT2 of the battery connection portion VT1, which corresponds to the first forming portion. The first busbar surface 522 of the first busbar portion 52 also corresponds to a first mounting portion to which the battery connection portion VT1 is attached. The battery connection surface VT2 of the battery connection portion VT1 corresponds to a first forming contact surface that abuts against the first busbar portion 52. The second busbar surface 532 of the second busbar portion 53 corresponds to a second mounting contact surface that abuts against the busbar connection surface BU2 of the busbar connection portion BU1, which corresponds to the second forming portion. The second busbar surface 532 also corresponds to a second mounting portion to which the busbar connection portion BU1 is attached. The busbar connection surface BU2 of the busbar connection portion BU1 corresponds to a second forming contact surface that abuts against the second busbar portion 53.

[0249] As shown in Figures 37 and 38, the first busbar portion 52 of this embodiment has a first recessed surface 522a formed in recess of the first busbar surface 522. In other words, the first busbar portion 52 is formed in recess of a part of the first busbar surface 522, and the battery connection portion VT1 connected to the first busbar surface 522 does not come into contact with the recessed portion.

[0250] The first recessed surface 522a is formed on the first busbar surface 522 at a position away from the first connection hole 521. Specifically, the first recessed surface 522a surrounds the first hole peripheral surface 522b, which is an annular surface surrounding the first connection hole 521, and is formed recessed from the first hole peripheral surface 522b. As a result, the first busbar surface 522 is configured such that the first hole peripheral surface 522b contacts the battery connection surface VT2, while the first recessed surface 522a does not contact the battery connection surface VT2. In this embodiment, the first hole peripheral surface 522b of the first busbar surface 522 corresponds to the first mounting contact surface that abuts against the battery connection portion VT1.

[0251] Furthermore, the first recessed surface 522a is formed in a predetermined range extending from the first other end 524 toward the other side in the second direction D2, but not reaching the first one end 523, excluding the first hole peripheral surface 522b. Specifically, the first recessed surface 522a is formed such that the other end in the second direction D2 is located on the other side of the second direction D2 than the other end in the second direction D2 of the battery connection surface VT2 when the battery connection part VT1 is connected to the first busbar portion 52. As a result, when the battery connection part VT1 is connected to the first busbar surface 522, only the first hole peripheral surface 522b of the first busbar portion 52 is in contact with the battery connection surface VT2, and the portion excluding the first hole peripheral surface 522b is not in contact with the battery connection surface VT2.

[0252] A conductive busbar 50 having such a first recessed surface 522a can be formed, for example, by cutting the portion that forms the first recessed surface 522a from the flattened first busbar portion 52 described in the first embodiment.

[0253] However, when attaching the battery connection part VT1 to the first busbar surface 522 with the first bolt B1, the mounting position of the battery connection part VT1 is not necessarily fixed. For example, the battery connection part VT1 may be mounted at an angle to the second direction D2, which is the direction in which the first busbar surface 522 extends. As a result of the shift in the mounting position of the battery connection part VT1 relative to the first busbar surface 522, the contact area between the first busbar surface 522 and the battery connection surface VT2 may change, and the current value detected by the current detection device 1 may change. Specifically, the current value calculated based on the electrical resistance value of the resistor 51 detected by the third sensing unit 25 via the first connection pin 61 and the second connection pin 62 may change due to the shift in the contact range between the first busbar surface 522 and the battery connection surface VT2.

[0254] In contrast, the current detection device 1 of this embodiment is configured to suppress such fluctuations in current value by restricting the flow of electricity between the first busbar portion 52 of the conductive busbar 50 and the battery connection portion VT1 by forming a first recessed surface 522a on the first busbar portion 52. The reason why fluctuations in current value can be suppressed will be explained with reference to Figures 39 to 43. Figure 39 shows a busbar without a recess 500 in which the first recessed surface 522a is not formed on the conductive busbar 50 of this embodiment. The busbar without a recess 500 has the same structure as the conductive busbar 50 of this embodiment, except that the first recessed surface 522a is not formed.

[0255] Figure 40 also shows the results of an experiment in which nine samples of the non-recessed busbar 500 were prepared, and the change in the electrical resistance value of the resistor 51 when the battery connector VT1 was attached to these nine samples was investigated. In this experiment, the battery connector VT1 was attached and removed five times for each of the nine non-recessed busbar 500 samples, and the electrical resistance value of the resistor 51 was calculated from the current value when a predetermined current was passed through it 10 times each time it was attached. In Figure 40, the difference between the second to fifth calculated values, with the first calculated value as the baseline, is shown for the electrical resistance values ​​calculated after the first attachment and removal of the nine samples five times.

[0256] Figure 41 shows the results of an experiment in which four samples of the conductive busbar 50 of this embodiment were prepared, and the change in the electrical resistance value of the resistor 51 was investigated when the battery connection part VT1 was attached to these four samples. In this experiment, the battery connection part VT1 was attached and removed from each of the four conductive busbar 50 samples five times, and the electrical resistance value of each resistor 51 was calculated from the current value when the same current value as in the experiment shown in Figure 40 was passed through it 10 times each time it was attached. In Figure 41, the difference between the second to fifth calculated values, with the first calculated value as the baseline, is shown when the electrical resistance values ​​were calculated after the first attachment and removal five times for the four samples.

[0257] In the case of the non-recessed busbar 500, where the first recessed surface 522a is not formed, the mounting position of the battery connection part VT1 may be slightly shifted when the battery connection part VT1 is attached by the first bolt B1. As a result, the contact area between the non-recessed busbar surface 501, which corresponds to the first busbar surface 522, and the battery connection surface VT2 changes, and the electrical resistance between the non-recessed busbar 500 and the battery connection part VT1 changes. Consequently, the current density of the current flowing from the non-recessed busbar 500 to the first connection pin 61, as indicated by the arrow in Figure 42, changes.

[0258] As a result, as shown in Figure 40, when current was passed through each of the nine sample non-recessed busbars 500 and the electrical resistance value was calculated, the difference between the second to fifth calculated values ​​relative to the first calculated value was relatively large. In particular, among the nine sample non-recessed busbars 500, the difference was largest when the fifth battery connection part VT1 was attached to the non-recessed busbar 500 of sample 8, with a difference of 0.6% from the first calculated value. In contrast, in the conductive busbar 50 of this embodiment, when the battery connection part VT1 is attached by the first bolt B1, only the surface 522b around the first hole contacts the battery connection surface VT2, and contact with the battery connection surface VT2 is limited to the parts other than the surface 522b around the first hole. Therefore, it becomes difficult for current to flow from the battery connection surface VT2 to the first busbar surface 522. That is, the first recessed surface 522a restricts the flow of current from the battery connection part VT1 to the first busbar part 52. Furthermore, even if the mounting positions of the conductive busbar 50 and the battery connection part VT1 are misaligned, the contact area between the first busbar surface 522 and the battery connection surface VT2 does not easily change, and therefore the electrical resistance between the first busbar part 52 and the battery connection part VT1 also does not easily change. For this reason, the current density of the current flowing from the first busbar part 52 to the first connection pin 61, as indicated by the arrow in Figure 43, remains almost constant.

[0259] As a result, as shown in Figure 41, when current was passed through each of the four conductive busbars 50 samples and the electrical resistance value was calculated, there was almost no difference between the second to fifth calculations, using the first calculation as a baseline. Furthermore, among the four conductive busbars 50 samples, the largest difference was observed when the fifth battery connection part VT1 was attached to the conductive busbar 50 of sample 3, but the difference from the first calculation was only 0.07%. This difference was about 1 / 10 of the difference for the non-recessed busbar 500 of sample 8, which had the largest difference.

[0260] Thus, the conductive busbar 50 of this embodiment can suppress fluctuations in electrical resistance due to misalignment of the mounting position between the conductive busbar 50 and the battery connection portion VT1, compared to a busbar 500 without a first recessed surface 522a. The first recessed surface 522a of this embodiment functions as a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1.

[0261] By the way, in this embodiment, the conductive busbar 50 does not have a recessed shape corresponding to the first recessed surface 522a formed on the second busbar surface 532. That is, in the conductive busbar 50, the recessed shape is formed only on the first busbar surface 522 of the first busbar portion 52, which is the one with the smaller dimension in the second direction D2, out of the first busbar portion 52 and the second busbar portion 53. The reason why the recessed shape is formed only on the first busbar surface 522 will be explained.

[0262] As described above, the distance from the first other end 524 to the first connection hole 521 is approximately equal to the distance from the second other end 534 to the second connection hole 531. In contrast, the distance from the first one end 523 to the first connection hole 521 is smaller than the distance from the second one end 533 to the second connection hole 531. Therefore, the distance from the first connection hole 521 to the first connection pin 61 is shorter than the distance from the second connection hole 531 to the second connection pin 62.

[0263] In a conductive busbar 50 with such a configuration, the effect of misalignment in the mounting position between the first busbar section 52 and the battery connection section VT1 tends to be greater than the effect of misalignment in the mounting position between the second busbar section 53 and the busbar connection section BU1. For example, suppose the amount of misalignment in the mounting position between the first busbar section 52 and the battery connection section VT1 is equal to the amount of misalignment in the mounting position between the second busbar section 53 and the busbar connection section BU1. In this case, the change in electrical resistance value due to the misalignment in the mounting position between the first busbar section 52 and the battery connection section VT1 will be greater than the change in electrical resistance value due to the misalignment in the mounting position between the second busbar section 53 and the busbar connection section BU1. This is because the distance from the contact portion between the first busbar section 52 and the battery connection section VT1 to the first connection pin 61 is smaller than the distance from the contact portion between the second busbar section 53 and the busbar connection section BU1 to the second connection pin 62, and is therefore more susceptible to the effects of misalignment in mounting position.

[0264] In contrast, in this embodiment, the conductive busbar 50 has a recessed shape formed only on the first busbar surface 522, which is the surface on which the distance from the connection hole to the connection pin is smaller than the first busbar surface 522. In other words, the first recessed surface 522a is formed only on the first busbar surface 522, which is the surface on which the distance from the first connection hole 521 to the first connection pin 61 is shorter than the distance from the second connection hole 531 to the second connection pin 62. Therefore, by forming a recessed shape only on the first busbar surface 522, it is possible to suppress fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater.

[0265] The other configurations are the same as in the first embodiment. The current detection device 1 of this embodiment can obtain the same effects and advantages as in the first embodiment, which are achieved from a configuration that is the same as or equivalent to that of the first embodiment.

[0266] As described above, the current detection device 1 of this embodiment includes a conductive busbar 50, a third sensing unit 25 that outputs a current detection signal corresponding to the current flowing through the conductive busbar 50, and a connection unit 60 that connects the conductive busbar 50 to the third sensing unit 25. Furthermore, the current detection device 1 includes a current limiting unit that limits the flow of current between the conductive busbar 50 and the battery connection unit VT1. The conductive busbar 50 includes a resistive unit 51, a first busbar unit 52 having lower electrical resistance than the resistive unit 51 and provided on one side of the second direction D2, and a second busbar unit 53 having lower electrical resistance than the resistive unit 51 and provided on the other side of the second direction D2. The connection unit 60 includes a first connection pin 61 connected to the first busbar unit 52 and connecting the first busbar unit 52 and the third sensing unit 25, and a second connection pin 62 connected to the second busbar unit 53 and connecting the second busbar unit 53 and the third sensing unit 25. The first busbar portion 52 has a portion around the first connection hole 521 to which the battery connection portion VT1 is attached, on one side in the second direction D2 from the position to which the first connection pin 61 is connected. The first recessed surface 522a, which is a current limiting portion, limits the flow of current due to contact between the periphery of the first hole peripheral surface 522b to which the battery connection portion VT1 is attached and the battery connection portion VT1.

[0267] According to this, the flow of current due to contact between the periphery of the first hole peripheral surface 522b and the battery connection part VT1 is restricted, thereby suppressing fluctuations in the electrical resistance between the first busbar part 52 and the battery connection part VT1 due to fluctuations in the mounting position of the first busbar part 52 and the battery connection part VT1. Therefore, fluctuations in the current density of the current flowing from the first busbar part 52 to the first connection pin 61 due to the misalignment of the mounting position of the first busbar part 52 and the battery connection part VT1 are suppressed. As a result, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance part 51 detected via the first connection pin 61 can be suppressed.

[0268] Furthermore, according to the above embodiment, the following effects can be obtained.

[0269] (1) In the above embodiment, the first busbar portion 52 has a first hole peripheral surface 522b that abuts against the battery connection portion VT1. The first recessed surface 522a surrounds the first hole peripheral surface 522b and is formed recessed from the first hole peripheral surface 522b, thereby limiting the contact area between the first hole peripheral surface 522b and the battery connection portion VT1 and restricting the flow of current between the first busbar portion 52 and the battery connection portion VT1.

[0270] According to this, fluctuations in the contact area between the first busbar surface 522 and the battery connection surface VT2 due to fluctuations in the mounting position of the first busbar section 52 and the battery connection section VT1 can be suppressed. Therefore, fluctuations in the current density of the current flowing from the first busbar section 52 to the first connection pin 61 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the first connection pin 61 can be suppressed.

[0271] Although this embodiment is a modification based on the first embodiment, it is possible to combine this embodiment with any of the first to twelfth embodiments.

[0272] (Modification of the 13th Embodiment) In the 13th embodiment described above, an example was described in which a recessed shape is formed only on the first busbar surface 522 of the first busbar portion 52, which is the one with the shorter distance from the connection hole to the connection pin among the first busbar portion 52 and the second busbar portion 53, but the invention is not limited to this.

[0273] For example, as shown in Figures 44 and 45, the second busbar portion 53 may have a second recessed surface 532a formed in recess of the second busbar surface 532. The second recessed surface 532a corresponds to the first recessed surface 522a and is formed at a position away from the second connection hole 531 on the second busbar surface 532. Specifically, the second recessed surface 532a surrounds the second hole peripheral surface 532b, which is an annular surface surrounding the second connection hole 531, and is formed recessed from the second hole peripheral surface 532b. Furthermore, the second recessed surface 532a is formed in a predetermined range extending from the second other side end 534 toward one side in the second direction D2, but not reaching the second one side end 533, excluding the second hole peripheral surface 532b. Specifically, the second recessed surface 532a is formed such that one end in the second direction D2 is located one side in the second direction D2 than one end in the second direction D2 of the busbar connection surface BU2 when the busbar connection part BU1 is connected to the second busbar part 53.

[0274] As a result, when the busbar connector BU1 is connected to the second busbar surface 532, only the second hole peripheral surface 532b of the second busbar portion 53 contacts the busbar connector surface BU2, and contact with the busbar connector surface BU2 is limited to the portion excluding the second hole peripheral surface 532b. Of the second busbar surface 532, the second hole peripheral surface 532b corresponds to the second mounting contact surface that abuts against the busbar connector BU1. Furthermore, the second recessed surface 532a functions as a current limiting portion that limits the flow of current due to contact between the second busbar portion 53 and the busbar connector BU1.

[0275] According to this, fluctuations in the contact area between the second busbar surface 532 and the busbar connection surface BU2 due to fluctuations in the mounting position of the second busbar section 53 and the busbar connection section BU1 can be suppressed. Therefore, fluctuations in the current density of the current flowing from the second connection pin 62 to the second busbar section 53 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the second connection pin 62 can be suppressed.

[0276] (14th Embodiment) Next, the 14th embodiment will be described with reference to Figures 46 to 49. In this embodiment, the shape of the first busbar portion 52 differs from that of the first and 13th embodiments. Also, in this embodiment, the battery VT and the conductive busbar 50 are connected to one side of the conductive busbar 50 in the third direction D3, which differs from the first embodiment. Other than this, it is the same as the first and 13th embodiments. For this reason, in this embodiment, the parts that differ from the first and 13th embodiments will be mainly described, and the parts that are the same as the first and 13th embodiments may be omitted from the description.

[0277] As shown in Figures 46 and 47, the first busbar portion 52 of this embodiment has no first recessed surface 522a, and instead has a first convex surface 522c that is formed to protrude from the first busbar surface 522. In other words, the first busbar portion 52 is formed with a part of the first busbar surface 522 protruding, and the battery connection portion VT1 connected to the first busbar surface 522 is configured to contact the protruding portion.

[0278] The first convex surface 522c is formed around the position where the first connection hole 521 is formed on the first busbar surface 522. Specifically, the first convex surface 522c surrounds the first hole peripheral surface 522b, which is an annular surface surrounding the first connection hole 521, and is formed adjacent to the first hole peripheral surface 522b at the same height as the first hole peripheral surface 522b. Therefore, the first busbar surface 522 is configured such that the first hole peripheral surface 522b and the first convex surface 522c are in contact with the battery connection surface VT2. In this embodiment, the first hole peripheral surface 522b and the first convex surface 522c of the first busbar surface 522 correspond to the first mounting contact surface that abuts against the battery connection portion VT1. Furthermore, the first hole peripheral surface 522b and the first convex surface 522c protrude from their periphery to one side in the third direction D3. In Figure 46, the boundary between the first hole peripheral surface 522b and the first convex surface 522c is shown by a dashed line.

[0279] Furthermore, the first convex surface 522c is formed in a predetermined range extending from the first other end 524 toward the other side in the second direction D2, but not reaching the first one end 523, excluding the first hole peripheral surface 522b. Specifically, the first convex surface 522c is formed such that the other end in the second direction D2 is located on one side of the second direction D2 than the other end in the second direction D2 of the battery connection surface VT2 when the battery connection part VT1 is connected to the first busbar portion 52. As a result, when the battery connection part VT1 is connected to the first busbar surface 522, the first busbar portion 52 contacts the battery connection surface VT2 with the first convex surface 522c in addition to the first hole peripheral surface 522b. In addition, contact between the first busbar portion 52 and the battery connection surface VT2 is limited to the parts excluding the first hole peripheral surface 522b and the first convex surface 522c.

[0280] Therefore, in this embodiment, the conductive busbar 50 on which the first convex surface 522c is formed makes it difficult for current to flow from the battery connection surface VT2 to the portion where the first convex surface 522c is not formed. In other words, the first convex surface 522c restricts the flow of current from the battery connection portion VT1 to the first busbar portion 52. The first convex surface 522c in this embodiment is a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and functions as a first limiting portion.

[0281] When forming a conductive busbar 50 having such a first convex surface 522c, for example, as shown in Figure 48, a step is formed in the first busbar portion 52 by press molding to provide the first hole peripheral surface 522b and the first convex surface 522c. However, no step is formed in the second busbar portion 53. Then, as shown in Figure 49, the conductive busbar 50 of this embodiment can be formed by forming a first connection hole 521 at the position where the first hole peripheral surface 522b of the first busbar portion 52 is formed, and forming a second connection hole 531 in the second busbar portion 53.

[0282] Furthermore, in this embodiment, the conductive busbar 50 does not have a protruding shape corresponding to the first convex surface 522c formed on the second busbar surface 532. That is, in the conductive busbar 50, the convex shape is formed only on the first busbar surface 522 of the first busbar portion 52, which is the side with the smaller distance from the connection hole to the connection pin. Therefore, it is possible to suppress fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater.

[0283] Other configurations are the same as those of the first and thirteenth embodiments. The current detection device 1 of this embodiment can obtain the same effects and advantages as those of the first and thirteenth embodiments, which are achieved from configurations that are the same as or equivalent to those of the first and thirteenth embodiments.

[0284] Furthermore, in this embodiment, when the battery connection part VT1 is attached by the first bolt B1, the conductive busbar 50 with the first convex surface 522c formed thereon makes it difficult for current to flow into areas other than the surface 522b around the first hole and the first convex surface 522c. In other words, the first convex surface 522c restricts the flow of current from the battery connection part VT1 to the first busbar part 52 in areas of the first busbar part 52 other than the surface 522b around the first hole and the first convex surface 522c. Also, even if the mounting positions of the conductive busbar 50 and the battery connection part VT1 are misaligned, the contact area between the first busbar surface 522 and the battery connection surface VT2 does not change easily, so the electrical resistance between the first busbar part 52 and the battery connection part VT1 does not change easily. For this reason, the current density of the current flowing from the first busbar part 52 to the first connection pin 61 does not change much. Therefore, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistor 51 detected via the first connection pin 61 can be suppressed.

[0285] Although this embodiment is a modification based on the first and thirteenth embodiments, this embodiment can be combined with any of the first to thirteenth embodiments.

[0286] (Modification of the 14th Embodiment) In the 14th embodiment described above, an example was described in which a convex shape is formed only on the first busbar surface 522 of the first busbar portion 52, which is the one with the shorter distance from the connection hole to the connection pin among the first busbar portion 52 and the second busbar portion 53, but the invention is not limited to this.

[0287] For example, as shown in Figures 50 and 51, the second busbar portion 53 may have a second convex surface 532c that protrudes from the second busbar surface 532. The second convex surface 532c corresponds to the first convex surface 522c and is formed around the position where the second connection hole 531 is formed on the second busbar surface 532. Specifically, the second convex surface 532c surrounds the second hole peripheral surface 532b, which is an annular surface surrounding the second connection hole 531, and is formed in conjunction with the second hole peripheral surface 532b at the same height as the second hole peripheral surface 532b. Furthermore, the second convex surface 532c is formed in a predetermined range extending from the second other side end 534 toward one side in the second direction D2, but not reaching the second one side end 533, excluding the second hole peripheral surface 532b. Specifically, the second convex surface 532c is formed such that one end in the second direction D2 is located on the other side of the second direction D2 from one end in the second direction D2 of the busbar connection surface BU2 when the busbar connection part BU1 is connected to the second busbar part 53.

[0288] As a result, when the busbar connector BU1 is connected to the second busbar surface 532, only the second hole peripheral surface 532b and the second convex surface 532c of the second busbar portion 53 come into contact with the busbar connector BU2. Furthermore, contact of the busbar connector BU2 with the portion of the second busbar portion 53 is limited to areas other than the second hole peripheral surface 532b and the second convex surface 532c. Of the second busbar surface 532, the second hole peripheral surface 532b and the second convex surface 532c correspond to the second mounting contact surface that comes into contact with the busbar connector BU1. The second hole peripheral surface 532b and the second convex surface 532c protrude to one side in the third direction D3 from their periphery. In Figure 50, the boundary between the second hole peripheral surface 532b and the second convex surface 532c is shown by a dashed line.

[0289] Therefore, in this embodiment, the conductive busbar 50 having the second convex surface 532c formed on it makes it difficult for current to flow into the busbar connection portion BU1 from the portion where the second convex surface 532c is not formed. In other words, the second convex surface 532c restricts the flow of current to the busbar connection portion BU1 from the portion where the second convex surface 532c is not formed. In this embodiment, the second convex surface 532c is a current limiting portion that restricts the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion.

[0290] According to this, fluctuations in the contact area between the second busbar surface 532 and the busbar connection surface BU2 due to fluctuations in the mounting position of the second busbar section 53 and the busbar connection section BU1 can be suppressed. Therefore, fluctuations in the current density of the current flowing from the second connection pin 62 to the second busbar section 53 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the second connection pin 62 can be suppressed.

[0291] (15th Embodiment) Next, the 15th embodiment will be described with reference to Figure 52. In this embodiment, the shape of the first busbar portion 52 differs from that of the first and 13th embodiments. Also, in this embodiment, the battery VT and the conductive busbar 50 are connected to one side of the conductive busbar 50 in the third direction D3, which differs from the first embodiment. Other than this, it is the same as the first and 13th embodiments. For this reason, in this embodiment, the parts that differ from the first and 13th embodiments will be mainly described, and the parts that are the same as the first and 13th embodiments may be omitted from the description.

[0292] As shown in Figure 52, the first busbar portion 52 of this embodiment has no first recessed surface 522a, and instead has a first notch portion 522d formed by cutting out a part of the first busbar portion 52. In other words, the first busbar portion 52 is formed with a smaller dimension in the first direction D1 of a part of the first busbar surface 522, and the range in which it contacts the battery connection portion VT1 connected to the first busbar surface 522 is limited.

[0293] The first notch 522d is formed around the portion where the first connection hole 521 is formed. Specifically, the first notch 522d is formed on one side and the other side in the first direction D1 of the portion of the first busbar portion 52 where the first connection hole 521 is formed. Furthermore, the first notch 522d is formed by cutting out a predetermined range from the first other side end 524 toward the other side in the second direction D2, but not reaching the first one side end 523. Specifically, the first notch 522d is formed such that the other side end in the second direction D2 is located on the other side in the second direction D2 of the battery connection surface VT2 when the battery connection portion VT1 is connected to the first busbar portion 52.

[0294] As a result, the dimension of the first busbar portion 52 in the first direction D1 where the first notch 522d is formed is smaller than the dimension of the portion in the first direction D1 on the other side of the first notch 522d in the second direction D2. When the battery connection portion VT1 is connected to the first busbar surface 522, only the portion of the first busbar portion 52 with a smaller width in the first direction D1 contacts the battery connection surface VT2, and the portion on the other side of the first notch 522d in the second direction D2 does not contact the battery connection surface VT2.

[0295] Therefore, in this embodiment, the conductive busbar 50 in which the first notch 522d is formed makes it difficult for current to flow from the battery connection surface VT2 to the first busbar surface 522. In other words, the first notch 522d restricts the flow of current from the battery connection surface VT1 to the first busbar surface 52. The first notch 522d in this embodiment is a current limiting part that restricts the flow of current due to contact between the first busbar surface 52 and the battery connection surface VT1, and functions as a first limiting part. Furthermore, the first busbar surface 522 of the first busbar surface 52 corresponds to a first mounting contact surface that abuts against the battery connection surface VT2 of the battery connection surface VT1 which corresponds to the first forming part. The area surrounding the part in which the first notch 522d of the first busbar surface 52 is formed corresponds to a first mounting part to which the battery connection surface VT1 is attached.

[0296] A conductive busbar 50 having such a first notch 522d can be formed, for example, by cutting the portion that will form the first notch 522d from the flattened first busbar portion 52 described in the first embodiment.

[0297] Furthermore, in this embodiment, the conductive busbar 50 does not have a notch shape corresponding to the first notch 522d formed on the second busbar surface 532. That is, of the conductive busbar 50, the notch shape is formed only on the first busbar portion 52, which is the side with the smaller distance from the connection hole to the connection pin. Therefore, fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater can be suppressed.

[0298] Other configurations are the same as those of the first and thirteenth embodiments. The current detection device 1 of this embodiment can obtain the same effects and advantages as those of the first and thirteenth embodiments, which are achieved from configurations that are the same as or equivalent to those of the first and thirteenth embodiments.

[0299] Furthermore, in this embodiment, when the conductive busbar 50 with the first notch 522d is attached by the first bolt B1, the contact area between the first busbar surface 522 and the battery connection surface VT2 is suppressed compared to a configuration in which the first notch 522d is not formed. Also, even if the mounting position of the conductive busbar 50 and the battery connection surface VT1 is misaligned, the contact area between the first busbar surface 522 and the battery connection surface VT2 is suppressed, so the electrical resistance between the first busbar portion 52 and the battery connection portion VT1 is less likely to fluctuate. As a result, the current density of the current flowing from the first busbar portion 52 to the first connection pin 61 is less likely to fluctuate. Consequently, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the first connection pin 61 can be suppressed.

[0300] Although this embodiment is a modification based on the first and thirteenth embodiments, this embodiment can be combined with any of the first to fourteenth embodiments.

[0301] (First Modification of the 15th Embodiment) In the 15th embodiment described above, an example was described in which a notch shape is formed only on the first busbar portion 52, which is the one with a smaller distance from the connection hole to the connection pin, of the first busbar portion 52 and the second busbar portion 53, but the invention is not limited to this.

[0302] For example, as shown in Figure 53, the second busbar portion 53 may have a second notch portion 532d formed by cutting out a part of the second busbar portion 53. In other words, the second busbar portion 53 may be configured such that a part of the second busbar surface 532 has a smaller dimension in the first direction D1, and the area in contact with the busbar connection portion BU1 connected to the second busbar surface 532 is limited.

[0303] The second notch 532d corresponds to the first notch 522d and is formed around the area where the second connection hole 531 is formed. Specifically, the second notch 532d is formed on one side and the other side in the first direction D1 of the area in the second busbar portion 53 where the second connection hole 531 is formed. Furthermore, the second notch 532d is formed by cutting out a predetermined range from the second other side end 534 toward one side in the second direction D2, but not reaching the second one side end 533. Specifically, the second notch 532d is formed such that one end in the second direction D2 is located one side in the second direction D2 than one end in the second direction D2 of the busbar connection surface BU2 when the busbar connection portion BU1 is connected to the second busbar portion 53.

[0304] As a result, the dimension of the second busbar portion 53 in the first direction D1 at the location where the second notch 532d is formed is smaller than the dimension of the portion in the first direction D1 at the location on one side of the second direction D2 from the location where the second notch 532d is formed. When the busbar connection portion BU1 is connected to the second busbar surface 532, only the portion of the second busbar portion 53 where the width in the first direction D1 is smaller contacts the busbar connection surface BU2. Furthermore, the second busbar portion 53 is configured so that the portion on one side of the second direction D2 from the second notch 532d does not contact the busbar connection surface BU2.

[0305] Therefore, in this embodiment, the conductive busbar 50 in which the second notch 532d is formed makes it difficult for current to flow from the second busbar surface 532 to the busbar connection surface BU2. In other words, the second notch 532d restricts the flow of current from the second busbar portion 53 to the busbar connection portion BU1. The second notch 532d in this embodiment is a current limiting portion that restricts the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion.

[0306] Furthermore, in this embodiment, when the conductive busbar 50 with the second notch 532d is attached to the busbar connection part BU1 by the second bolt B2, the contact area between the second busbar surface 532 and the busbar connection surface BU2 is suppressed compared to a configuration in which the second notch 532d is not formed. Also, even if the mounting positions of the conductive busbar 50 and the busbar connection part BU1 are misaligned, the electrical resistance between the second busbar surface 532 and the busbar connection surface BU2 is suppressed, so the electrical resistance between the second busbar part 53 and the busbar connection part BU1 is less likely to fluctuate. As a result, the current density of the current flowing from the second connection pin 62 to the second busbar part 53 is less likely to fluctuate. Consequently, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance part 51 detected via the second connection pin 62 can be suppressed.

[0307] (Second Modification of the Fifteenth Embodiment) In the fifteenth embodiment described above, the first notch 522d is formed on one side and the other side of the first busbar portion 52 in the first direction D1. An example has been described in which the end of the first notch 522d on the other side in the second direction D2 is located on the other side of the second direction D2 from the battery connection surface VT2, but the invention is not limited to this.

[0308] For example, the first notch 522d may be formed on only one of the two sides of the first busbar portion 52 in the first direction D1. Alternatively, the end of the first notch 522d on the other side in the second direction D2 may be formed so that it is located on one side of the second direction D2 relative to the battery connection surface VT2.

[0309] (16th Embodiment) Next, the 16th embodiment will be described with reference to Figure 54. This embodiment differs from the first and 13th embodiments in that the surface of the first busbar surface 522 of the first busbar portion 52 is surface-treated. Also, this embodiment differs from the first embodiment in that the battery VT and the conductive busbar 50 are connected to one side of the conductive busbar 50 in the third direction D3. Other than this, it is the same as the first and 13th embodiments. For this reason, in this embodiment, the parts that differ from the first and 13th embodiments will be mainly described, and the parts that are the same as the first and 13th embodiments may be omitted from the description.

[0310] As shown in Figure 54, the first busbar portion 52 of this embodiment has no first recessed surface 522a, and instead has a first thin film portion 522e of a thin film member formed by surface treatment on a part of the first busbar surface 522. In other words, the first busbar portion 52 has a part of the first busbar surface 522 that has been surface treated, and the thickness of the surface-treated portion is slightly thicker than the other portions. That is, the dimension in the third direction D3 of the portion of the first busbar portion 522e where the first thin film portion 522e is formed is larger than the dimension in the third direction D3 of the other portions. In Figure 54, the first thin film portion 522e is hatched with diagonal lines to make the portion where the first thin film portion 522e is formed easier to understand.

[0311] The first thin film portion 522e is formed around the position where the first connection hole 521 is formed on the first busbar surface 522. Specifically, the first thin film portion 522e is formed in an annular shape surrounding the first connection hole 521. In contrast, the first busbar surface 522 is not surface-treated except in the area where the first thin film portion 522e is formed. Therefore, the area where the first thin film portion 522e is formed on the first busbar surface 522 protrudes slightly to one side in the third direction D3 compared to the area where the first thin film portion 522e is not formed.

[0312] Therefore, when the battery connection portion VT1 is fastened by the first bolt B1, the first busbar portion 52 is configured such that the first thin film portion 522e first comes into contact with the first busbar surface 522. Then, as the first bolt B1 is tightened, the first thin film portion 522e is compressed and its thickness decreases, and the first thin film portion 522e and the battery connection portion VT1 come into close contact.

[0313] Furthermore, the fastening force when tightening the first bolt B1 reduces the thickness of the first thin film portion 522e, which may cause the portion of the first busbar surface 522 where the first thin film portion 522e is not formed to come into contact with the battery connection portion VT1. However, even if the portion where the first thin film portion 522e is not formed comes into contact, the adhesion between the portion where the first thin film portion 522e is not formed and the battery connection portion VT1 will be less than the adhesion between the portion where the first thin film portion 522e is formed and the battery connection portion VT1.

[0314] In other words, by forming a first thin film portion 522e on the first busbar surface 522, the adhesion between the portion where the first thin film portion 522e is formed and the battery connection portion VT1 can be improved. Conversely, the adhesion between the portion where the first thin film portion 522e is not formed and the battery connection portion VT1 can be reduced. This reduces the contact resistance between the portion where the first thin film portion 522e is formed and the battery connection portion VT1, and increases the contact resistance between the portion where the first thin film portion 522e is not formed and the battery connection portion VT1.

[0315] Therefore, in this embodiment, the conductive busbar 50 on which the first thin film portion 522e is formed makes it difficult for current to flow from the battery connection surface VT2 to the area around the first thin film portion 522e on the first busbar surface 522. In other words, the first thin film portion 522e restricts the flow of current from the battery connection portion VT1 to the first busbar portion 52. The first thin film portion 522e in this embodiment is a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and functions as a first limiting portion. Furthermore, the first busbar surface 522 of the first busbar portion 52 corresponds to a first mounting facing surface that faces the battery connection surface VT2 of the battery connection portion VT1 which corresponds to the first forming portion. The portion on which the first thin film portion 522e of the first busbar portion 52 is formed corresponds to a first mounting portion on which the battery connection portion VT1 is attached.

[0316] The material constituting the first thin film portion 522e can be a relatively soft, conductive material such as tin or nickel. By using a relatively soft, conductive material, the first thin film portion 522e is more easily deformed when the battery connection portion VT1 is fastened by the first bolt B1, thereby improving the adhesion between the first thin film portion 522e and the battery connection portion VT1. However, the material constituting the first thin film portion 522e is not limited to tin or nickel; various conductive materials can be used.

[0317] Furthermore, in this embodiment, the conductive busbar 50 does not have a thin film member corresponding to the first thin film portion 522e formed on the second busbar surface 532. That is, of the conductive busbar 50, the surface treatment is applied only to the first busbar surface 522 of the first busbar portion 52, which is the side with the smaller distance from the connection hole to the connection pin. Therefore, it is possible to suppress fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater.

[0318] Other configurations are the same as those of the first and thirteenth embodiments. The current detection device 1 of this embodiment can obtain the same effects and advantages as those of the first and thirteenth embodiments, which are achieved from configurations that are the same as or equivalent to those of the first and thirteenth embodiments.

[0319] Furthermore, in this embodiment, when the battery connection part VT1 is attached by the first bolt B1, current is less likely to flow into the area surrounding the first thin film portion 522e of the conductive busbar 50 on which the first thin film portion 522e is formed. In other words, the first thin film portion 522e restricts the flow of current from the battery connection part VT1 to the first busbar portion 52 to the area of ​​the first busbar portion 52 where the first thin film portion 522e is not formed. Also, even if the mounting positions of the conductive busbar 50 and the battery connection part VT1 are misaligned, the contact resistance between the first busbar surface 522 and the battery connection surface VT2 is less likely to fluctuate. As a result, the current density of the current flowing from the first busbar portion 52 to the first connection pin 61 remains almost constant. Consequently, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the first connection pin 61 can be suppressed.

[0320] Although this embodiment is a modification based on the first and thirteenth embodiments, this embodiment can be combined with any of the first to fifteenth embodiments.

[0321] (Modification of the 16th Embodiment) In the 16th embodiment described above, an example was described in which a thin film member is formed only on the first busbar surface 522 of the first busbar portion 52, which is the one with the shorter distance from the connection hole to the connection pin among the first busbar portion 52 and the second busbar portion 53, but the invention is not limited to this.

[0322] For example, as shown in Figure 55, the second busbar portion 53 may have a configuration in which a second thin film portion 532e of a thin film member is formed on a part of the second busbar surface 532 by surface treatment. The second thin film portion 532e corresponds to the first thin film portion 522e and is formed around the position in the second busbar surface 532 where the second connection hole 531 is formed. Specifically, the second thin film portion 532e is formed in an annular shape surrounding the second connection hole 531. Therefore, when the busbar connection portion BU1 is fastened by the second bolt B2, the second busbar portion 533 is configured such that the second thin film portion 532e first comes into contact with the second busbar surface 532. Then, as the second bolt B2 is tightened, the second thin film portion 532e is compressed and its thickness decreases, and the second thin film portion 532e and the busbar connection portion BU1 come into close contact. In Figure 55, the area where the second thin film portion 532e is formed is shown with hatched diagonal lines.

[0323] Furthermore, the thickness of the second thin film portion 532e decreases due to the fastening force when tightening the second bolt B2, which may cause the portion of the second busbar surface 532 where the second thin film portion 532e is not formed to come into contact with the busbar connection portion BU1. However, even when the portion where the second thin film portion 532e is not formed comes into contact, the adhesion between the portion where the second thin film portion 532e is not formed and the busbar connection portion BU1 will be less than the adhesion between the portion where the second thin film portion 532e is formed and the busbar connection portion BU1.

[0324] In other words, by forming a second thin film portion 532e on the second busbar surface 532, the adhesion between the portion where the second thin film portion 532e is formed and the busbar connection portion BU1 can be improved. Conversely, the adhesion between the portion where the second thin film portion 532e is not formed and the busbar connection portion BU1 can be reduced. This reduces the contact resistance between the portion where the second thin film portion 532e is formed and the busbar connection portion BU1, and increases the contact resistance between the portion where the second thin film portion 532e is not formed and the busbar connection portion BU1.

[0325] Therefore, in this embodiment, the conductive busbar 50 on which the second thin film portion 532e is formed becomes less susceptible to current flowing from the busbar connection surface BU2 to the area around the second thin film portion 532e on the second busbar surface 532. In other words, the second thin film portion 532e restricts the flow of current from the busbar connection portion BU1 to the second busbar portion 53. The second thin film portion 532e in this embodiment is a current limiting portion that restricts the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion. Furthermore, the second busbar surface 532 of the second busbar portion 53 corresponds to a second mounting opposing surface that faces the busbar connection surface BU2 of the busbar connection portion BU1, which corresponds to the second forming portion. The portion on which the second thin film portion 532e of the second busbar portion 53 is formed corresponds to a second mounting portion to which the busbar connection portion BU1 is attached.

[0326] According to this, even if the mounting positions of the conductive busbar 50 and the busbar connection part BU1 are misaligned, the contact resistance between the second busbar surface 532 and the busbar connection surface BU2 is unlikely to fluctuate. Therefore, the current density of the current flowing from the second connection pin 62 to the second busbar part 53 remains almost constant. Consequently, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance part 51 detected via the second connection pin 62 can be suppressed.

[0327] (17th Embodiment) Next, the 17th embodiment will be described with reference to Figure 56. In this embodiment, the area around the first thin film portion 522e is oxidized, which is different from the 16th embodiment. Other than this, it is the same as the 16th embodiment. For this reason, in this embodiment, the parts that differ from the 16th embodiment will be mainly described, and the parts that are the same as the 16th embodiment may be omitted from the description.

[0328] As shown in Figure 56, in this embodiment, a first oxide film 522f is formed on the first busbar surface 522 around the first thin film portion 522e, increasing the electrical resistance of the first busbar surface 522. The first oxide film 522f can be formed by oxidizing the first busbar surface 522, and is formed around the first thin film portion 522e, surrounding it. Furthermore, the first oxide film 522f is formed in a predetermined range from the first other end 524 toward the other side in the second direction D2, but not reaching the first one end 523, excluding the first thin film portion 522e. Specifically, the first oxide film 522f is formed such that the other end in the second direction D2 is located on the other side of the second direction D2 than the other end in the second direction D2 of the battery connection surface VT2 when the battery connection portion VT1 is connected to the first busbar portion 52. In Figure 56, in order to make it easier to see the area where the first oxide film 522f is formed, the first oxide film 522f is hatched with diagonal lines that are oriented differently from those of the first thin film portion 522e.

[0329] As a result, the electrical resistance of the portion of the first busbar surface 522 where the first oxide film 522f is formed increases. Therefore, when the battery connection portion VT1 is connected to the first busbar surface 522 and the first oxide film 522f and the battery connection surface VT2 come into contact, it becomes more difficult for current to flow from the battery connection surface VT2 to the portion of the first busbar surface 522 where the first oxide film 522f is formed. In other words, the first oxide film 522f further restricts the flow of current from the battery connection portion VT1 to the first busbar portion 52. In this embodiment, the first oxide film 522f functions as a first mounting resistance film that increases the electrical resistance of the first busbar surface 522.

[0330] Furthermore, in this embodiment, even if the mounting position of the conductive busbar 50 and the battery connection part VT1 is misaligned, the current density of the current flowing from the first busbar part 52 to the first connection pin 61 remains almost constant. Therefore, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance part 51 detected via the first connection pin 61 can be suppressed.

[0331] Furthermore, the method for increasing the electrical resistance of the first busbar surface 522 is not limited to the first oxide film 522f formed by oxidizing the first busbar surface 522, but various materials can be used as long as they can increase the electrical resistance. For example, instead of the first oxide film 522f, the electrical resistance of the first busbar surface 522 may be increased by forming a non-conductive insulating film around the first thin film portion 522e.

[0332] (Modification of the 17th Embodiment) In the 17th embodiment described above, an example was described in which the first thin film portion 522e and the first oxide film 522f are formed only on the first busbar surface 522, but the invention is not limited thereto.

[0333] As shown in Figure 57, in addition to the second thin film portion 532e described in the modified example of the 16th embodiment, a second oxide film 532f that increases the electrical resistance of the second busbar surface 532 may be formed on the second busbar surface 532 around the second thin film portion 532e. The second oxide film 532f can be formed by oxidizing the second busbar surface 532 and is formed around the second thin film portion 532e, surrounding the second thin film portion 532e. Furthermore, the second oxide film 532f is formed in a predetermined range extending from the second other end portion 534 toward one side in the second direction D2, but not reaching the second one-side end portion 533, in a portion excluding the second thin film portion 532e. Specifically, the second oxide film 532f is formed such that one end in the second direction D2 is located one side in the second direction D2 of the busbar connection surface BU2 when the busbar connection part BU1 is connected to the second busbar part 53. In Figure 57, the second oxide film 532f is hatched with diagonal lines in a different direction from the second thin film part 532e to make the area where the second oxide film 532f is formed easier to understand.

[0334] As a result, the electrical resistance of the portion of the second busbar surface 532 where the second oxide film 532f is formed increases. Therefore, when the busbar connection portion BU1 is connected to the second busbar surface 532 and the second oxide film 532f and the busbar connection surface BU2 come into contact, it becomes more difficult for current to flow from the portion of the second busbar surface 532 where the second oxide film 532f is formed to the busbar connection surface BU2. In other words, the second oxide film 532f further restricts the flow of current from the second busbar portion 53 to the busbar connection portion BU1. In this embodiment, the second oxide film 532f functions as a second mounting resistance film that increases the electrical resistance of the second busbar surface 532.

[0335] Furthermore, in this embodiment, even if the mounting position of the conductive busbar 50 and the busbar connection part BU1 is misaligned, the current density of the current flowing from the second connection pin 62 to the second busbar part 53 remains almost constant. Therefore, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance part 51 detected via the second connection pin 62 can be suppressed.

[0336] (Eighteenth Embodiment) Next, the eighteenth embodiment will be described with reference to Figures 58 to 60. This embodiment differs from the first and thirteenth embodiments in that a first washer W1 is arranged between the first busbar portion 52 and the battery connection portion VT1. Also, this embodiment differs from the first embodiment in that the battery VT and the conductive busbar 50 are connected to one side of the conductive busbar 50 in the third direction D3. Other than this, it is the same as the first and thirteenth embodiments. For this reason, in this embodiment, we will mainly describe the parts that differ from the first and thirteenth embodiments, and we may omit the description of parts that are the same as the first and thirteenth embodiments.

[0337] As shown in Figures 58 and 59, in this embodiment, the conductive busbar 50 has a first busbar surface 522 of the first busbar portion 52 and a battery connection surface VT2 of the battery connection portion VT1 facing each other in the third direction D3. A first washer W1, as shown in Figures 58 to 60, is sandwiched between the first busbar surface 522 and the battery connection surface VT2. Therefore, when the first busbar portion 52 of this embodiment is fastened by the first bolt B1, it is connected to the battery connection portion VT1 via the first washer W1.

[0338] The first washer W1 is made of a conductive material, such as metal. The first washer W1 is a thin plate shape with a plate surface in the third direction D3 and is formed in an annular shape. The first washer W1 also has a first washer through hole WH1 that communicates with the first connection hole 521 and is formed so that the first bolt B1 can be inserted into it. The outer diameter of the first washer W1 is smaller than the dimension of the first busbar surface 522 in the first direction D1 and also smaller than the dimension of the battery connection surface VT2 in the first direction D1. Furthermore, the outer diameter of the first washer W1 is smaller than the dimension of the second direction D2 in the range where the first busbar surface 522 and the battery connection surface VT2 face the third direction D3.

[0339] Therefore, when the first washer W1 is placed between the first busbar surface 522 and the battery connection surface VT2, the area in which the first washer W1 contacts the first busbar surface 522 is smaller than the area in which the first busbar surface 522 and the battery connection surface VT2 face each other. Also, the area in which the first washer W1 contacts the battery connection surface VT2 is smaller than the area in which the first busbar surface 522 and the battery connection surface VT2 face each other. In other words, the area in which the first busbar portion 52 and the battery connection portion VT1 contact each other via the first washer W1 is smaller compared to the case where the first washer W1 is not placed between them. Therefore, compared to the case where the first washer W1 is not placed, it becomes more difficult for current to flow between the first busbar portion 52 and the battery connection portion VT1.

[0340] In other words, the first washer W1 reduces the contact area between the first busbar surface 522 and the battery connection surface VT2 to a size smaller than the overlapping area of ​​the first busbar surface 522 and the battery connection surface VT2 in the third direction D3, thereby restricting the flow of current between the first busbar portion 52 and the battery connection portion VT1. The first washer W1 in this embodiment is a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and functions as a first limiting portion. Furthermore, the first busbar surface 522 of the first busbar portion 52 corresponds to a first mounting facing surface that faces the battery connection surface VT2 of the battery connection portion VT1 which corresponds to the first forming portion.

[0341] Furthermore, in this embodiment, the conductive busbar 50 does not have a member corresponding to the first washer W1 between the second busbar portion 53 and the busbar connection portion BU1. That is, in the conductive busbar 50, a member that limits the contact area is arranged only on the first busbar portion 52, which is the side of the first busbar portion 52 and the second busbar portion 53 where the distance from the connection hole to the connection pin is smaller. Therefore, it is possible to suppress fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater. Other configurations are the same as in the first and thirteenth embodiments. The current detection device 1 of this embodiment can obtain the same effects as those obtained from the first and thirteenth embodiments, which have the same or equivalent configurations.

[0342] Furthermore, in this embodiment, the conductive busbar 50, in which a first washer W1 is positioned between the first busbar portion 52 and the battery connection portion VT1, makes it difficult for current to flow from the battery connection portion VT1 to the first busbar portion 52 when the battery connection portion VT1 is attached by the first bolt B1. In other words, the first washer W1 restricts the flow of current from the battery connection portion VT1 to the first busbar portion 52. Also, even if the mounting positions of the conductive busbar 50 and the battery connection portion VT1 are misaligned, fluctuations in the contact area between the first busbar surface 522 and the first washer W1, and between the battery connection surface VT2 and the first washer W1 can be suppressed. Therefore, since fluctuations in the current density of the current flowing from the first busbar portion 52 to the first connection pin 61 are suppressed, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the first connection pin 61 can be suppressed.

[0343] Although this embodiment is a modification based on the first and thirteenth embodiments, this embodiment can be combined with any of the first to seventeenth embodiments.

[0344] (Modification of the 18th Embodiment) In the 18th embodiment described above, an example was described in which the first washer W1 is placed only between the first busbar portion 52 and the battery connection portion VT1, which is the first busbar portion 52 on the side with the smaller distance from the connection hole to the connection pin. However, the invention is not limited to this.

[0345] For example, as shown in Figures 61 to 63, a second washer W2 may be sandwiched between the second busbar portion 53 and the busbar connection portion BU1. The second washer W2 corresponds to the first washer W1 and is made of a conductive material, such as metal. The second washer W2 is a thin plate shape with a plate surface in the third direction D3 and is formed in an annular shape. The second washer W2 also has a second washer through hole WH2 that communicates with the second connection hole 531 and is formed so that a second bolt B2 can be inserted. Furthermore, the outer diameter of the second washer W2 is smaller than the dimension of the second busbar surface 532 in the first direction D1 and also smaller than the dimension of the busbar connection surface BU2 in the first direction D1. Furthermore, the outer diameter of the second washer W2 is smaller than the dimension in the second direction D2 in the range where the second busbar surface 532 and the busbar connection surface BU2 face the third direction D3.

[0346] Therefore, when the second washer W2 is placed between the second busbar surface 532 and the busbar connection surface BU2, the area in which the second washer W2 contacts the second busbar surface 532 is smaller than the area in which the second busbar surface 532 and the busbar connection surface BU2 face each other. Also, the area in which the second washer W2 contacts the busbar connection surface BU2 is smaller than the area in which the second busbar surface 532 and the busbar connection surface BU2 face each other. In other words, the area in which the second busbar portion 53 and the busbar connection portion BU1 contact each other via the second washer W2 is smaller compared to the case where the second washer W2 is not placed in between. Therefore, compared to the case where the second washer W2 is not placed, it becomes more difficult for current to flow between the second busbar portion 53 and the busbar connection portion BU1.

[0347] In other words, the second washer W2 reduces the contact area between the second busbar surface 532 and the busbar connection surface BU2 to less than the overlapping area of ​​the second busbar surface 532 and the busbar connection surface BU2 in the third direction D3, thereby limiting the flow of current between the second busbar portion 53 and the busbar connection portion BU1. The second washer W2 in this embodiment is a current limiting portion that limits the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion. Furthermore, the second busbar surface 532 of the second busbar portion 53 corresponds to a second mounting opposing surface that faces the busbar connection surface BU2 of the busbar connection portion BU1, which corresponds to the second forming portion.

[0348] Furthermore, in this embodiment, the conductive busbar 50, in which a second washer W2 is positioned between the second busbar portion 53 and the busbar connection portion BU1, makes it difficult for current to flow from the busbar connection portion BU1 to the second busbar portion 53 when the busbar connection portion BU1 is attached by the second bolt B2. In other words, the second washer W2 restricts the flow of current from the busbar connection portion BU1 to the second busbar portion 53. Also, even if the mounting positions of the conductive busbar 50 and the busbar connection portion BU1 are misaligned, fluctuations in the contact area between the second busbar surface 532 and the second washer W2, and between the busbar connection surface BU2 and the second washer W2 can be suppressed. Therefore, since fluctuations in the current density of the current flowing from the second busbar portion 53 to the second connection pin 62 are suppressed, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the second connection pin 62 can be suppressed.

[0349] (19th Embodiment) Next, the 19th embodiment will be described with reference to Figures 64 and 65. This embodiment differs from the 18th embodiment in that the first washer W1 is omitted and replaced by a first collar C1. For this reason, this embodiment will mainly describe the parts that differ from the 18th embodiment, and the parts that are the same as the 18th embodiment may be omitted from the description.

[0350] As shown in Figures 64 and 65, in this embodiment, the conductive busbar 50 has a first collar C1 sandwiched between the first busbar surface 522 and the battery connection surface VT2. Therefore, when the first busbar portion 52 of this embodiment is fastened by the first bolt B1, it is connected to the battery connection portion VT1 via the first collar C1.

[0351] The first collar C1 is made of a conductive material, such as metal. The first collar C1 is made of a crimp nut, for example, and has a cylindrical first cylindrical portion C11 that fits into the first connection hole 521, and a thin plate annular first ring portion C12 provided on one side and the other side of the first cylindrical portion C11 in the third direction D3. The outer diameter of the first ring portion C12 is larger than the outer diameter of the first cylindrical portion C11. The first ring portion C12 also protrudes from one side and the other side of the first cylindrical portion C11 in the third direction D3, and the first ring portion C12 on one side in the third direction D3 is sandwiched between the first busbar surface 522 and the battery connection surface VT2. The first collar C1 also has a first collar through hole C13 that communicates with the first connection hole 521 and is formed so that the first bolt B1 can be inserted into it.

[0352] Furthermore, the outer diameter of the first ring portion C12 is smaller than the dimension of the first busbar surface 522 in the first direction D1, and also smaller than the dimension of the battery connection surface VT2 in the first direction D1. In addition, the outer diameter of the first ring portion C12 is smaller than the dimension of the second direction D2 in the range where the first busbar surface 522 and the battery connection surface VT2 face the third direction D3.

[0353] Therefore, when the first ring portion C12 of the first collar C1 is positioned between the first busbar surface 522 and the battery connection surface VT2, the area in which the first ring portion C12 contacts the first busbar surface 522 becomes smaller than the area in which the first busbar surface 522 and the battery connection surface VT2 face each other. Also, the area in which the first ring portion C12 contacts the battery connection surface VT2 becomes smaller than the area in which the first busbar surface 522 and the battery connection surface VT2 face each other. In other words, the area in which the first busbar portion 52 and the battery connection portion VT1 contact via the first ring portion C12 becomes smaller compared to the case where the first ring portion C12 is not positioned between them. Therefore, compared to the case where the first ring portion C12 is not positioned, it becomes more difficult for current to flow between the first busbar portion 52 and the battery connection portion VT1.

[0354] In other words, the first ring portion C12 reduces the contact area between the first busbar surface 522 and the battery connection surface VT2 to a size smaller than the overlapping area of ​​the first busbar surface 522 and the battery connection surface VT2 in the third direction D3, thereby restricting the flow of current between the first busbar portion 52 and the battery connection portion VT1. The first collar C1 in this embodiment is a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and functions as a first limiting portion. Furthermore, the first busbar surface 522 of the first busbar portion 52 corresponds to a first mounting facing surface that faces the battery connection surface VT2 of the battery connection portion VT1 which corresponds to the first forming portion.

[0355] Furthermore, in this embodiment, the conductive busbar 50 does not have a member corresponding to the first ring portion C12 between the second busbar portion 53 and the busbar connection portion BU1. That is, in the conductive busbar 50, a member that limits the contact area is arranged only on the first busbar portion 52, which is the side of the first busbar portion 52 and the second busbar portion 53 where the distance from the connection hole to the connection pin is smaller. Therefore, it is possible to suppress fluctuations in the electrical resistance value on the side where the effect of misalignment of the mounting position is greater.

[0356] The other configurations are the same as those of the 18th embodiment. The current detection device 1 of this embodiment can obtain the same effects and advantages as those of the 18th embodiment, which are achieved from a configuration that is the same as or equivalent to that of the 18th embodiment.

[0357] Furthermore, in this embodiment, the conductive busbar 50, in which the first collar C1 is positioned between the first busbar portion 52 and the battery connection portion VT1, makes it difficult for current to flow from the battery connection portion VT1 to the first busbar portion 52 when the battery connection portion VT1 is attached by the first bolt B1. In other words, the first collar C1 restricts the flow of current from the battery connection portion VT1 to the first busbar portion 52. Also, even if the mounting positions of the conductive busbar 50 and the battery connection portion VT1 are misaligned, fluctuations in the contact area between the first busbar surface 522 and the first ring portion C12, and the contact area between the battery connection surface VT2 and the first ring portion C12 can be suppressed. Therefore, since fluctuations in the current density of the current flowing from the first busbar portion 52 to the first connection pin 61 are suppressed, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the first connection pin 61 can be suppressed.

[0358] Although this embodiment is a modification based on the 18th embodiment, it is possible to combine this embodiment with any of the first to 17th embodiments.

[0359] (Modification of the 19th Embodiment) In the 19th embodiment described above, an example was described in which the first color C1 is arranged only between the first busbar portion 52 and the battery connection portion VT1, which is the first busbar portion 52 on the side with a smaller distance from the connection hole to the connection pin. However, the invention is not limited to this.

[0360] For example, as shown in Figures 66 and 67, a second collar C2 may be sandwiched between the second busbar portion 53 and the busbar connection portion BU1. The second collar C2 corresponds to the first collar C1 and is made of a conductive material, such as metal.

[0361] The second collar C2 is, for example, made of a crimp nut and has a cylindrical second cylindrical portion C21 that fits into the second connection hole 531, and thin plate annular second ring portions C22 provided on one side and the other side of the second cylindrical portion C21 in the third direction D3. The outer diameter of the second ring portion C22 is larger than the outer diameter of the second cylindrical portion C21. The second ring portion C22 also protrudes from one side and the other side of the second cylindrical portion C21 in the third direction D3, and the second ring portion C22 on one side in the third direction D3 is sandwiched between the second busbar surface 532 and the busbar connection surface BU2. The second collar C2 has a second collar through hole C23 that communicates with the second connection hole 531 and is formed so that the second bolt B2 can be inserted.

[0362] Furthermore, the outer diameter of the second ring portion C22 is smaller than the dimension of the second busbar surface 532 in the first direction D1, and also smaller than the dimension of the busbar connection surface BU2 in the first direction D1. In addition, the outer diameter of the second ring portion C22 is smaller than the dimension of the second direction D2 in the range where the second busbar surface 532 and the busbar connection surface BU2 face the third direction D3.

[0363] Therefore, when the second ring portion C22 of the second collar C2 is positioned between the second busbar surface 532 and the busbar connection surface BU2, the area in which the second ring portion C22 contacts the second busbar surface 532 is smaller than the area in which the second busbar surface 532 and the busbar connection surface BU2 face each other. Also, the area in which the second ring portion C22 contacts the busbar connection surface BU2 is smaller than the area in which the second busbar surface 532 and the busbar connection surface BU2 face each other. In other words, the area in which the second busbar portion 53 and the busbar connection portion BU1 contact each other via the second ring portion C22 is smaller compared to the case where the second ring portion C22 is not positioned between them. Therefore, compared to the case where the second ring portion C22 is not positioned, it becomes more difficult for current to flow between the second busbar portion 53 and the busbar connection portion BU1.

[0364] In other words, the second ring portion C22 reduces the contact area between the second busbar surface 532 and the busbar connection surface BU2 to a size smaller than the overlapping area of ​​the second busbar surface 532 and the busbar connection surface BU2 in the third direction D3, thereby restricting the flow of current between the second busbar portion 53 and the busbar connection portion BU1. The second collar C2 in this embodiment is a current limiting portion that restricts the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion. Furthermore, the second busbar surface 532 of the second busbar portion 53 corresponds to a second mounting opposing surface that faces the busbar connection surface BU2 of the busbar connection portion BU1, which corresponds to the second forming portion.

[0365] Furthermore, in this embodiment, the conductive busbar 50, in which the second collar C2 is positioned between the second busbar portion 53 and the busbar connection portion BU1, makes it difficult for current to flow from the second busbar portion 53 to the busbar connection portion BU1 when the busbar connection portion BU1 is attached by the second bolt B2. In other words, the second collar C2 restricts the flow of current from the second busbar portion 53 to the busbar connection portion BU1. In addition, even if the mounting positions of the conductive busbar 50 and the busbar connection portion BU1 are misaligned, fluctuations in the contact area between the second busbar surface 532 and the second ring portion C22, and the contact area between the busbar connection surface BU2 and the second ring portion C22 can be suppressed. Therefore, since fluctuations in the current density of the current flowing from the second connection pin 62 to the second busbar portion 53 are suppressed, fluctuations in the current value calculated by the third sensing unit 25 based on the electrical resistance value of the resistance portion 51 detected via the second connection pin 62 can be suppressed.

[0366] (Perspectives of this Disclosure) As will be apparent from the above description of embodiments and modifications, the disclosure herein includes at least the following perspectives:

[0367] (Problem) The battery sensor described in Patent Document 1 comprises a resistor unit and a current measuring device for detecting the voltage drop across the resistor unit. The resistor unit is formed of a measuring resistor, a first connection part connected to one side of the measuring resistor, and a second connection part connected to the other side of the measuring resistor. A clamp is connected to the first connection part, and a cable is connected to the second connection part. The battery sensor then detects the voltage drop across the measuring resistor and calculates the current flowing from the clamp through the resistor unit to the cable based on Ohm's law, using the detected voltage drop and the electrical resistance of the measuring resistor.

[0368] Incidentally, the mounting positions when the first connector is connected to the clamp and when the second connector is connected to the cable are not necessarily fixed. If the mounting positions shift, the contact area between the first connector and the clamp and the contact area between the second connector and the cable will change, and the electrical resistance of these contact points may change. As a result, the battery sensor may not be able to accurately calculate the current flowing through the measured resistance.

[0369] In view of the above points, the purpose of this disclosure is to provide a current detection device capable of improving current detection accuracy.

[0370] [Perspective 5-1] A current detection device used in a circuit system having a conductive path forming part that forms a conductive path through which electric current flows, comprising: a flat conductive member (50) having one direction as the extension direction through which electric current flows; a current detection unit (25) that outputs a current detection signal corresponding to the current flowing through the conductive member; a connection unit (60) that connects the conductive member to the current detection unit; and a current limiting unit (522a, 532a, 522c, 532c, 522d, 532d, 522e, 532e, W1, W2, C1, C2) that limits the flow of electric current between the conductive member and the conductive path forming part, wherein the conductive member includes a resistive part (51), a first conductive part (52) having less electrical resistance than the resistive part and provided on one side of the resistive part in the extension direction, and a second conductive part (53) having less electrical resistance than the resistive part and provided on the other side of the resistive part in the extension direction. The connection portion includes a first connection portion (61) connected to the first conductive portion and connecting the first conductive portion and the current detection portion, and a second connection portion (62) connected to the second conductive portion and connecting the second conductive portion and the current detection portion; the conductive path forming portion includes a first forming portion (V) connected to the first conductive portion and a second forming portion (BU) connected to the second conductive portion; the first conductive portion has a first mounting portion to which the first forming portion is attached, located on one side in the extension direction from the position where the first connection portion is connected; the second conductive portion has a second mounting portion to which the second forming portion is attached, located on one side in the extension direction from the position where the second connection portion is connected; and the current limiting portion limits the flow of current due to contact between at least one of the following: between the first mounting portion and the first forming portion, and between the second mounting portion and the second forming portion.

[0371] [Perspective 5-2] The first mounting portion has a first mounting contact surface (522b) that abuts against the first forming portion, the second mounting portion has a second mounting contact surface (532b) that abuts against the second forming portion, and the current limiting portion is provided on at least one of the first mounting portion and the second mounting portion, with the current limiting portion provided on the first mounting portion being designated as the first limiting portion (522a), and the current limiting portion provided on the second mounting portion being designated as the second limiting portion (532a), the first limiting portion surrounds the first mounting contact surface and is formed recessed from the first mounting contact surface, and limits the contact area between the first mounting portion and the first forming portion to limit the flow of current between the first mounting portion and the first forming portion, The current detection device according to viewpoint 5-1, wherein the second limiting portion surrounds the second mounting contact surface and is formed recessed from the second mounting contact surface, thereby limiting the contact area between the second mounting portion and the second forming portion and restricting the flow of current between the second mounting portion and the second forming portion.

[0372] [Perspective 5-3] The first mounting portion has a first mounting contact surface (522b, 522c) that abuts against the first forming portion, the second mounting portion has a second mounting contact surface (532b, 532c) that abuts against the second forming portion, and the current limiting portion is provided on at least one of the first mounting portion and the second mounting portion, with the current limiting portion provided on the first mounting portion being designated as the first limiting portion (522c) and the current limiting portion provided on the second mounting portion being designated as the second limiting portion (532c), the first limiting portion causes the first mounting contact surface to protrude from the periphery of the first mounting contact surface, thereby limiting the contact area between the first mounting portion and the first forming portion and restricting the flow of current between the first mounting portion and the first forming portion, The current detection device according to viewpoint 5-1, wherein the second limiting portion causes the second mounting contact surface to protrude from the periphery of the second mounting contact surface, thereby limiting the contact area between the second mounting portion and the second forming portion and restricting the flow of current between the second mounting portion and the second forming portion.

[0373] [Perspective 5-4] The first mounting portion has a first mounting contact surface (522) that abuts against the first forming portion, the second mounting portion has a second mounting contact surface (532) that abuts against the second forming portion, the current limiting portion is provided on at least one of the first mounting portion and the second mounting portion, the current limiting portion provided on the first mounting portion is designated as the first limiting portion (522d), the current limiting portion provided on the second mounting portion is designated as the second limiting portion (532d), and the direction intersecting the extension direction and the thickness direction of the conductive member is designated as the width direction, The current detection device according to viewpoint 5-1, wherein the first limiting portion is a notch that reduces the width of the first mounting contact surface, and the width dimension of the portion of the first mounting contact surface where the first limiting portion is provided is made smaller than the width dimension of the portion of the first conductive portion on the other side in the extension direction from the portion where the first limiting portion is provided, thereby limiting the contact area between the first mounting portion and the first forming portion and restricting the flow of current between the first mounting portion and the first forming portion; and the second limiting portion is a notch that reduces the width of the second mounting contact surface, and the width dimension of the portion of the second mounting contact surface where the second limiting portion is provided is made smaller than the width dimension of the portion of the second conductive portion on the one side in the extension direction from the portion where the second limiting portion is provided, thereby limiting the contact area between the second mounting portion and the second forming portion and restricting the flow of current between the second mounting portion and the second forming portion.

[0374] [Perspective 5-5] The first mounting portion has a first mounting facing surface (522) facing the first forming portion, the second mounting portion has a second mounting facing surface (532) facing the second forming portion, and the current limiting portion is provided on at least one of the first mounting portion and the second mounting portion, with the current limiting portion provided on the first mounting portion being designated as the first limiting portion (522e), and the current limiting portion provided on the second mounting portion being designated as the second limiting portion (532e), the first limiting portion is a thin film member formed on a part of the first mounting facing surface, and the contact resistance between the periphery of the portion on the first mounting facing surface where the first limiting portion is formed and the first forming portion is made greater than the contact resistance between the portion on the first mounting facing surface where the first limiting portion is formed and the first forming portion, thereby limiting the flow of current between the first mounting portion and the first forming portion. The current detection device according to viewpoint 5-1, wherein the second limiting portion is a thin film member formed on a part of the second mounting opposing surface, and the contact resistance between the area around the portion on the second mounting opposing surface where the second limiting portion is formed and the second forming portion is made greater than the contact resistance between the portion on the second mounting opposing surface where the second limiting portion is formed and the second forming portion, thereby limiting the flow of current between the second mounting portion and the second forming portion.

[0375] [Perspective 5-6] The current detection device according to Perspective 5-5, wherein the first mounting opposing surface has a first mounting resistance film (522f) formed around the first limiting portion that increases the electrical resistance of the first mounting opposing surface, and the second mounting opposing surface has a second mounting resistance film (532f) formed around the second limiting portion that increases the electrical resistance of the second mounting opposing surface.

[0376] [Perspective 5-7] The first mounting portion has a first mounting opposing surface (522) facing the first forming portion, the second mounting portion has a second mounting opposing surface (532) facing the second forming portion, the current limiting portion has a portion that is sandwiched between the first mounting opposing surface and the first forming portion and between the second mounting opposing surface and the second forming portion, the portion of the current limiting portion sandwiched between the first mounting opposing surface and the first forming portion is defined as the first limiting portion (W1, C1), and the portion sandwiched between the second mounting opposing surface and the second forming portion is defined as the second limiting portion (W2, C2), The current detection device according to viewpoint 5-1, wherein the first limiting portion is formed such that the area in contact with the first mounting opposing surface and the area in contact with the first forming portion are each smaller than the area in which the first mounting opposing surface and the first forming portion face each other, thereby limiting the area in which the first mounting portion and the first forming portion contact via the first limiting portion and restricting the flow of current between the first mounting portion and the first forming portion; and the second limiting portion is formed such that the area in contact with the second mounting opposing surface and the area in contact with the second forming portion are each smaller than the area in which the second mounting opposing surface and the second forming portion face each other, thereby limiting the area in which the second mounting portion and the second forming portion contact via the second limiting portion and restricting the flow of current between the second mounting portion and the second forming portion.

[0377] [Perspective 5-8] The current detection device according to Perspective 5-7, wherein the first limiting portion is composed of a first washer (W1) sandwiched between the first mounting opposing surface and the first forming portion, and the second limiting portion is composed of a second washer (W2) sandwiched between the second mounting opposing surface and the second forming portion.

[0378] [Perspective 5-9] The current detection device according to Perspective 5-7, wherein the first mounting portion has a first connection hole (521) into which a first mounting member (B1) for mounting to the first forming portion is inserted, the second mounting portion has a second connection hole (531) into which a second mounting member (B2) for mounting to the second forming portion is inserted, the first limiting portion is composed of a first collar (C1) having a first cylindrical portion (C11) that fits into the first connection hole and into which the first mounting member is inserted, and a first ring portion (C12) that is connected to the first cylindrical portion and is sandwiched between the first mounting opposing surface and the first forming portion, and the second limiting portion is composed of a second collar (C2) having a second cylindrical portion (C21) that fits into the second connection hole and into which the second mounting member is inserted, and a second ring portion (C22) that is connected to the second cylindrical portion and is sandwiched between the second mounting opposing surface and the second forming portion.

[0379] (20th Embodiment) Next, the 20th embodiment will be described with reference to Figure 68. The circuit system of this embodiment differs from the 13th embodiment in that the first recessed surface 522a of the first busbar portion 52 in the current detection device 1 is eliminated, and instead, a battery recessed surface VT2a corresponding to the first recessed surface 522a is formed in the battery connection portion VT1. Other than this, it is the same as the 13th embodiment. For this reason, in this embodiment, the parts that differ from the 13th embodiment will be mainly described, and the parts that are the same as the 13th embodiment may be omitted from the description.

[0380] As shown in Figure 68, the battery connection portion VT1 of this embodiment has a battery recessed surface VT2a formed as a recess in the battery connection surface VT2. In other words, the battery connection portion VT1 is formed as a recess in a part of the battery connection surface VT2, and the first busbar surface 522 of the first busbar portion 52 connected to the battery connection surface VT2 does not come into contact with the recessed portion.

[0381] The battery recess surface VT2a has the same shape as the first recess surface 522a and is formed at a position away from the battery through-hole VTH on the battery connection surface VT2. Specifically, the battery recess surface VT2a surrounds an annular portion of a predetermined size that surrounds the battery through-hole VTH, and is formed recessed from the annular portion. Therefore, the battery connection surface VT2 is configured such that the portion surrounded by the battery recess surface VT2a contacts the first busbar surface 522, while the battery recess surface VT2a does not contact the first busbar surface 522. A battery connection portion VT1 having such a battery recess surface VT2a can be formed, for example, by cutting the portion that forms the battery recess surface VT2a from the battery connection portion VT1 described in the 13th embodiment.

[0382] As a result, when the first busbar surface 522 is connected to the battery connection surface VT2, only the portion of the battery connection surface VT2 surrounded by the battery recess surface VT2a contacts the first busbar surface 522, and the battery recess surface VT2a and the first busbar surface 522 do not come into contact. In this embodiment, the portion of the battery connection surface VT2 surrounded by the battery recess surface VT2a corresponds to the first formed contact surface. Furthermore, the battery recess surface VT2a functions as a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and thus functions as the first limiting portion.

[0383] The other configurations are the same as those of the 13th embodiment. The circuit system of this embodiment can obtain the same effects and advantages as those obtained from a configuration similar to or equivalent to that of the current detection device 1 described in the 13th embodiment.

[0384] This makes it possible to suppress fluctuations in the contact area between the first busbar surface 522 and the battery connection surface VT2 due to fluctuations in the mounting position of the first busbar section 52 and the battery connection section VT1. Therefore, fluctuations in the current density of the current flowing from the first busbar section 52 to the first connection pin 61 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the first connection pin 61 can be suppressed.

[0385] Although this embodiment is a modification based on the thirteenth embodiment, it is possible to combine this embodiment with any of the first to nineteenth embodiments.

[0386] (Modification of the 20th Embodiment) In the 20th embodiment described above, an example was described in which a battery recess surface VT2a corresponding to the first recess surface 522a is formed on the battery connection portion VT1. However, as shown in Figure 69, a busbar recess surface BU2a corresponding to the second recess surface 532a may be formed on the busbar connection portion BU1.

[0387] The busbar recessed surface BU2a has the same shape as the second recessed surface 532a and is formed at a position away from the busbar through hole BUH on the busbar connection surface BU2. Specifically, the busbar recessed surface BU2a surrounds an annular portion of a predetermined size that surrounds the busbar through hole BUH, and is formed recessed from the annular portion. Therefore, the portion of the busbar recessed surface BU2a that is surrounded by the busbar recessed surface BU2a is in contact with the second busbar surface 532, while the busbar recessed surface BU2a is not in contact with the second busbar surface 532. In this embodiment, the portion of the busbar connection surface BU2 surrounded by the busbar recessed surface BU2a corresponds to the second formed contact surface. Furthermore, the busbar recessed surface BU2a functions as a current limiting portion that limits the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and functions as a second limiting portion.

[0388] According to this, fluctuations in the contact area between the second busbar surface 532 and the busbar connection surface BU2 due to fluctuations in the mounting position of the second busbar section 53 and the busbar connection section BU1 can be suppressed. Therefore, fluctuations in the current density of the current flowing from the second connection pin 62 to the second busbar section 53 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the second connection pin 62 can be suppressed.

[0389] (21st Embodiment) Next, the 21st embodiment will be described with reference to Figure 70. The circuit system of this embodiment differs from the 14th embodiment in that the first convex surface 522c of the first busbar portion 52 in the current detection device 1 is eliminated, and instead, a battery protruding surface VT2b corresponding to the first convex surface 522c is formed on the battery connection portion VT1. Other than this, it is the same as the 14th embodiment. For this reason, in this embodiment, the parts that differ from the 14th embodiment will be mainly described, and the parts that are the same as the 14th embodiment may be omitted from the description.

[0390] As shown in Figure 70, the battery connection portion VT1 of this embodiment has a battery protruding surface VT2b that is formed to protrude from the battery connection surface VT2. In other words, the battery connection portion VT1 is formed by a part of the battery connection surface VT2 protruding, and the first busbar surface 522 of the first busbar portion 52 connected to the battery connection surface VT2 is in contact with the protruding portion.

[0391] The battery protruding surface VT2b has the same shape as the first convex surface 522c and is formed around the position where the battery through-hole VTH is formed on the battery connection surface VT2. Specifically, the battery protruding surface VT2b surrounds an annular portion of a predetermined size that surrounds the battery through-hole VTH, and is formed in conjunction with the annular portion at the same height as the annular portion. Therefore, the portion of the battery connection surface VT2 surrounded by the battery protruding surface VT2b and the battery protruding surface VT2b contact the first busbar surface 522, while the portion surrounded by the battery protruding surface VT2b and the portion excluding the battery protruding surface VT2b do not contact the first busbar surface 522. In this embodiment, the portion of the battery connection surface VT2 surrounded by the battery protruding surface VT2b and the battery protruding surface VT2b correspond to the first formed contact surface. Furthermore, the battery protruding surface VT2b functions as a current limiting portion that restricts the flow of current due to contact between the first busbar portion 52 and the battery connection portion VT1, and thus functions as a first limiting portion.

[0392] The other configurations are the same as those of the 14th embodiment. The circuit system of this embodiment can obtain the same effects as those of the 13th embodiment, which are achieved from a configuration similar to or equivalent to that of the current detection device 1 described in the 14th embodiment.

[0393] This makes it possible to suppress fluctuations in the contact area between the first busbar surface 522 and the battery connection surface VT2 due to fluctuations in the mounting position of the first busbar section 52 and the battery connection section VT1. Therefore, fluctuations in the current density of the current flowing from the first busbar section 52 to the first connection pin 61 are suppressed, and thus fluctuations in the current value calculated by the third sensing section 25 based on the electrical resistance value of the resistance section 51 detected via the first connection pin 61 can be suppressed.

[0394] Although this embodiment is a modification based on the 14th embodiment, it is possible to combine this embodiment with any of the first to 20th embodiments.

[0395] (Modification of the 21st Embodiment) In the 21st embodiment described above, an example was described in which a battery protruding surface VT2b corresponding to the first convex surface 522c is formed on the battery connection portion VT1. However, as shown in Figure 71, a busbar protruding surface BU2b corresponding to the second convex surface 532c may be formed on the busbar connection portion BU1.

[0396] The busbar protruding surface BU2b has the same shape as the second convex surface 532c and is formed around the position where the busbar through hole BUH is formed on the busbar connecting surface BU2. Specifically, the busbar protruding surface BU2b surrounds an annular portion of a predetermined size that surrounds the busbar through hole BUH, and is formed in conjunction with the annular portion at the same height as the annular portion. Therefore, the portion of the busbar recessed surface BU2a surrounded by the busbar protruding surface BU2b and the busbar protruding surface BU2b contact the second busbar surface 532. The portion of the busbar recessed surface BU2a surrounded by the busbar protruding surface BU2b and the portion excluding the busbar protruding surface BU2b do not contact the second busbar surface 532. In this embodiment, the portion of the busbar connecting surface BU2 surrounded by the busbar protruding surface BU2b and the busbar protruding surface BU2b correspond to the second formed contact surface. Furthermore, the busbar protruding surface BU2b functions as a current limiting portion that restricts the flow of current due to contact between the second busbar portion 53 and the busbar connection portion BU1, and thus functions as a second limiting port...

Claims

1. A temperature detection device used in a current detection device, comprising: a conductive member (50) which is in the shape of a flat plate and has one direction of extension as its extension direction through which current flows; a temperature detection unit (71, 72) which outputs a temperature detection signal corresponding to the temperature of the conductive member; and a connection unit (60) which connects the conductive member to the temperature detection unit, wherein the conductive member includes a resistive part (51), a first conductive part (52) which has less electrical resistance than the resistive part and is provided on one side of the resistive part in the extension direction, and a second conductive part (53) which has less electrical resistance than the resistive part and is provided on the other side of the resistive part in the extension direction, the connection unit includes a first connection unit (61) which is connected to the first conductive part and a second connection unit (62) which is connected to the second conductive part, and the temperature detection unit is positioned such that the distance from the second connection unit to the temperature detection unit is smaller than the distance from the first connection unit to the temperature detection unit. The second conductive part is a temperature detection device having a higher thermal resistance compared to the first conductive part.

2. The temperature detection device according to claim 1, wherein the direction perpendicular to the thickness direction and the extension direction of the conductive member is defined as the width direction, and the line passing through the center of the resistive portion in the extension direction and along the width direction is defined as the axis of symmetry (SL), the first conductive portion and the second conductive portion have a non-symmetrical shape with respect to the axis of symmetry.

3. The temperature detection device according to claim 2, wherein the second conductive portion is larger in the extension direction compared to the first conductive portion.

4. The temperature detection device according to claim 3, wherein the first conductive portion has a first connection hole (521) into which a first fastening member (B1) for attaching the first conductive portion is inserted, and the second conductive portion has a second connection hole (531) into which a second fastening member (B2) for attaching the second conductive portion is inserted, and the second connection hole has a larger inner diameter than the first connection hole.

5. The temperature detection device according to claim 2, wherein the second conductive portion includes a narrow portion (535) whose width is smaller in the width direction compared to the width of the first conductive portion.

6. The temperature detection device according to claim 5, wherein the second conductive portion has a notch (536) at at least one end of one end in the width direction and the other end in the width direction.

7. The temperature detection device according to claim 2, wherein the second conductive portion has a second conductive through-hole (537) formed through the second conductive portion in the plate thickness direction.

8. The temperature detection device according to claim 7, wherein the first conductive portion has a first conductive through-hole (526) formed through the first conductive portion in the plate thickness direction, and the size of the first conductive through-hole in the direction along the plate thickness direction is different from the size of the second conductive through-hole in the direction along the plate thickness direction.

9. The temperature detection device according to claim 2, wherein the first conductive portion includes a thickened portion (525) whose size in the thickness direction is larger than that of the second conductive portion in the thickness direction.

10. The temperature detection device according to claim 2, wherein the second conductive portion includes a thin portion (538) whose size in the thickness direction is smaller than that of the first conductive portion in the thickness direction.

11. The temperature detection device according to claim 10, wherein the reduced thickness portion is formed by a recessed portion (5381) that is formed in the direction of the plate thickness.

12. The temperature detection device according to claim 1, wherein the second conductive part is composed of a material with a higher thermal conductivity than the first conductive part.

13. A current detection device comprising: a temperature detection device according to any one of claims 1 to 11; and a current detection unit (25) that outputs a current detection signal corresponding to the current flowing through the conductive member based on the electrical resistance value of the conductive member and the voltage applied to the conductive member.

14. The current detection device according to claim 13, further comprising a resistance correction unit (25) that corrects the electrical resistance value based on the temperature detection signal, wherein the current detection unit outputs the current detection signal based on the electrical resistance value corrected by the resistance correction unit and the voltage applied to the conductive member.

15. The current detection device according to claim 14, comprising a housing (10) for housing the temperature detection unit, wherein the current detection unit and the resistance correction unit are located outside the housing.

16. The current detection device according to claim 13, further comprising a magnetic detection unit (23, 24) that outputs a magnetic field detection signal corresponding to the magnetic field to be measured, which is generated when an electric current flows through the conductive member.

17. The current detection device according to claim 1, further comprising magnetic detection units (23, 24) that output a magnetic field detection signal corresponding to the magnetic field to be measured, which is generated when an electric current flows through the conductive member.

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