Power supply device

Abstract

To connect terminals to each other and determine increase of the resistance of the contact point between the terminals.SOLUTION: In a power source device which turns off one of a positive electrode side relay and a negative electrode side relay which is a pre-charge relay and which a restriction resistance bypasses and turns on the other of a positive electrode side relay and a negative electrode side relay and a pre-charge relay when a system is activated and which controls the positive electrode side relay, a negative electrode side relay, and a pre-charge relay so that precharge of a capacitor is started, whether the contact resistance of at least one of a first contact point as the contact point between one pair of positive electrode side terminals and a second contact point as a contact point between one pair of negative electrode side terminals was increased on the basis of the current of the power source since pre-charging was started.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a power supply device. [Background Art]

[0002] Conventionally, there has been proposed a terminal pair having a male connector terminal and a female connector terminal, wherein when fitting the male connector terminal and the female connector terminal, wiping is performed by sliding one of the two terminals against the other terminal (see, for example, Patent Document 1). In this terminal pair, wiping is performed such that a contact resistance (contact resistance value) of the two terminals measured after wiping is equal to or lower than a reference contact resistance value. [Prior Art Literature] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent No. 5742791 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] However, in the above-described terminal pair, after wiping, that is, after the two terminals are connected to each other, one of the two terminals may slide against the other terminal. In this case, the contact resistance of the two terminals may increase over time. Therefore, it is desired to determine an increase in contact resistance between the terminals even after the terminals are connected to each other.

[0005] A main object of the power supply device of the present invention is to determine an increase in contact resistance between terminals after the terminals are connected to each other. [Means for Solving the Problem]

[0006] The power supply device of the present invention adopts the following means to achieve the above-mentioned main object.

[0007] A first power supply device of the present invention includes: a power supply; Capacitors attached to the positive and negative terminal lines of the first power line, A relay device comprising a positive-side relay and a negative-side relay provided on the positive-side line and the negative-side line of a second power line from the power source, and a pre-charge circuit in which a pre-charge relay and a limiting resistor are connected in series to bypass the positive-side relay or the negative-side relay, A set of positive terminals connected to each other to connect the positive terminal line of the first power line and the positive terminal line of the second power line, A set of at least one pair of negative terminals connected to each other to connect the negative terminal line of the first power line and the negative terminal line of the second power line, A control device controls the positive-side relay, the negative-side relay, and the pre-charge relay so that when the system is started, it turns off one of the positive-side relay and the negative-side relay that bypasses the pre-charge relay and the limiting resistor, and turns on the other of the positive-side relay and the negative-side relay, and the pre-charge relay, so that the pre-charging of the capacitor begins. A power supply device comprising, The control device determines, based on the current of the power supply since the start of precharging, whether the contact resistance of at least one of the first contact, which is the contact between a pair of positive terminals, and the second contact, which is the contact between a pair of negative terminals, has increased. This is the gist of it.

[0008] The second power supply device of the present invention is Power supply and Capacitors attached to the positive and negative terminal lines of the first power line, A relay device comprising a positive-side relay and a negative-side relay provided on the positive-side line and the negative-side line of a second power line from the power source, and a pre-charge circuit in which a pre-charge relay and a limiting resistor are connected in series to bypass the positive-side relay or the negative-side relay, The positive terminal and negative terminal of the first power line are connected to the positive and negative terminal lines, respectively. The positive and negative terminals of the second power line are connected to the first positive terminal and the second negative terminal, and the second positive terminal is connected to the first negative terminal. A control device that, when starting the system, turns off one of the positive and negative relays that is bypassed by the precharge relay and the limiting resistor, and turns on the other of the positive and negative relays and the precharge relay to start precharging the capacitor, and after the precharging is complete, turns on the one relay and turns off the precharge relay to start the system, A power supply device comprising, The relay device has an additional precharge circuit in which an additional precharge relay and an additional limiting resistor with a resistance value smaller than the limiting resistor are connected in series to bypass the positive side relay or the negative side relay. The control device, at a predetermined time, turns off the relay that is bypassed by the additional precharge relay and the additional limiting resistor among the positive side relay and the negative side relay, and turns on the relay that is not bypassed by the additional precharge relay and the additional limiting resistor among the positive side relay and the negative side relay, and the additional precharge relay to start the additional precharge of the capacitor, and determines whether the contact resistance of at least one of the first contact, which is the contact between the first positive side terminal and the second positive side terminal, and the second contact, which is the contact between the first negative side terminal and the second negative side terminal, has increased, based on the current of the power supply after the start of the additional precharge, This is the gist of it. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram of the configuration of an electric vehicle 20 equipped with a power supply unit according to one embodiment. [Figure 2] A flowchart illustrating an example of a processing routine. [Figure 3] An illustrative diagram showing an example of the time change of voltage Vc, etc., after precharging has started. [Figure 4] An explanatory diagram showing an example of the relationship between the time variation of current Ib and the magnitude of contact resistance. [Figure 5] An illustrative diagram showing an example of the time variation of voltage Vc, etc., immediately after the start of pre-charging. [Figure 6] A schematic diagram of the configuration of electric vehicle 120 equipped with a modified power supply unit. [Modes for carrying out the invention]

[0010] Next, embodiments for carrying out the present invention will be described using examples. [Examples]

[0011] Figure 1 is a schematic diagram showing the configuration of an electric vehicle 20 equipped with a power supply device as one embodiment of the present invention. In the figure, inductors Lwhp and Lwhn, and resistors Rwhp and Rwhn are the parasitic inductance and parasitic resistance of the positive and negative terminal lines of the wire harness WH. Resistor Rb is the internal resistance of the battery 36. Inductor Lc and resistor Rc are the equivalent series inductance and equivalent series resistance of the capacitor 35. The electric vehicle 20 of the embodiment includes a motor 32, a power control unit PCU, a battery pack BP, and an electronic control unit (control device) 50, as shown in the figure. The power control unit PCU and the battery pack BP are connected via a wire harness WH. In this embodiment, the power supply device corresponds to the capacitor 35 of the power control unit PCU, the battery pack BP, the first positive terminals Tp1 and Twhp1, the second positive terminals Tp2 and Twhp2, the first negative terminals Tn1 and Twhn1, the second negative terminals Tn2 and Twhn2, and the electronic control unit 50.

[0012] The motor 32 is configured as a synchronous generator-motor, and includes a rotor embedded with permanent magnets and a stator wound with a three-phase coil. The rotor of this motor 32 is connected to a drive shaft 26 which is coupled to drive wheels 22a, 22b via a differential gear 24.

[0013] The power control unit PCU includes an inverter 34 and a capacitor 35.

[0014] The inverter 34 is used for driving the motor 32 and connected to a first power line 42. This inverter 34 includes six transistors T11 to T16 and six diodes D11 to D16 connected in anti-parallel to the transistors T11 to T16. Two transistors of T11 to T16 are arranged in pairs, each pair being located on the source side and the sink side with respect to the positive line and the negative line of the first power line 42 respectively. Each connection point between a pair of the transistors T11 to T16 is connected to a corresponding phase of the three-phase coils (U-phase, V-phase, W-phase) of the motor 32. Therefore, when a voltage is applied to the inverter 34, the electronic control unit 50 adjusts the duty ratio of the on-time of the paired transistors T11 to T16, thereby forming a rotating magnetic field in the three-phase coils and rotationally driving the motor 32.

[0015] The capacitor 35 is attached to the positive and negative terminal lines of the first power line 42. The first positive and first negative terminals Tp1 and Tn1 are connected to the positive and negative terminal lines of the first power line 42. The first positive and first negative terminals Tp1 and Tn1 have metal parts formed by plating copper. The metal parts of the first positive and first negative terminals Tp1 and Tn1 are connected to the metal parts of the first positive and first negative terminals Twhp1 and Twhn1, which are connected to the positive and negative terminal lines of the wire harness WH. The metal parts of the first positive terminal and first negative terminals Twhp1 and Twhn1 are formed by plating copper. Contact resistors Rcp1 and Rcn1 are formed at the contact points between the first positive terminal Tp1 and the first positive terminal Twhp1, and between the first negative terminal Tn1 and the first negative terminal Twhn1.

[0016] The battery pack BP comprises a battery 36 and a relay device 48. The battery 36 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery and is connected to the second power line 44. The relay device 48 is provided on the second power line 44. This relay device 48 comprises a positive-side relay SB (the other relay) provided on the positive-side line of the second power line 44, a negative-side relay SG (the other relay) provided on the negative-side line of the second power line 44, and a pre-charge circuit SC in which a pre-charge relay SP and a limiting resistor SR are connected in series to bypass the negative-side relay SG. Here, the pre-charge circuit SC is a circuit for charging (pre-charging) the capacitor 35 before turning on the positive-side relay SB and the negative-side relay SG when supplying power from the battery 36 to the inverter 34. The relay device 48 is turned on and off by an electronic control unit 50 to connect and disconnect the battery 36 side and the capacitor 35 side. The second power line 44 is connected to the second positive and second negative terminals Tp2 and Tn2. The second positive and second negative terminals Tp2 and Tn2 have metal parts formed by plating copper. The metal parts of the second positive and second negative terminals Tp2 and Tn2 are connected to the metal parts of the second positive terminal and second negative terminals Twhp2 and Twhn2, which are connected to the positive and negative lines of the wire harness WH. The metal parts of the second positive and second negative terminals Tp2 and Tn2 are formed by plating copper. Contact resistors Rcp2 and Rcn2 are formed at the contacts between the second positive terminal Tp2 and the second positive terminal Twhp2, and between the second negative terminal Tn2 and the second negative terminal Twhn2. The resistance value of the limiting resistor SR is set to be larger than that of the resistors Rwhp, Rwhn, Rc, and the contact resistors Rcp1, Rcp2, Rcn1, and Rcn2, for example, to several tens of ohms.

[0017] The electronic control unit 50 is configured as a microprocessor centered on a CPU 52. In addition to the CPU 52, it includes a ROM 54 for storing processing programs, a non-volatile memory 56 for storing data, a RAM for temporarily storing data, and input / output ports. Signals from various sensors are input to the electronic control unit 50 via the input ports. Examples of signals input to the electronic control unit 50 include the rotational position θm of the rotor of the motor 32 from a rotational position detection sensor 32a that detects the rotational position of the rotor of the motor 32, and the phase currents Iu and Iv flowing through the motor 32 from a current sensor that detects the current flowing through each phase of the motor 32. Other examples include the voltage Vb of the battery 36 from a voltage sensor attached between the terminals of the battery 36, and the current Ib of the battery 36 from a current sensor attached to the output terminal of the battery 36. Furthermore, the voltage Vc of the capacitor 35 (first power line 42) from a voltage sensor 35a attached between the terminals of the capacitor 35 can also be mentioned. In addition, the ignition signal from the ignition switch 60 and the shift position SH from the shift position sensor 62, which detects the operating position of the shift lever 61, can also be mentioned. Furthermore, the accelerator opening Acc from the accelerator pedal position sensor 64, which detects the amount the accelerator pedal 63 is pressed, the brake pedal position B from the brake pedal position sensor 66, which detects the amount the brake pedal 65 is pressed, and the vehicle speed V from the vehicle speed sensor 68 can also be mentioned. Various control signals are output from the electronic control unit 50 via output ports. An example of a signal output from the electronic control unit 50 is the switching control signal to transistors T11 to T16 of the inverter 34. The electronic control unit 50 calculates the electrical angle θe and rotational speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 detected by the rotational position detection sensor 32a.

[0018] In the electric vehicle 20 of this embodiment, the electronic control unit 50 performs the following driving control. In driving control, the required torque Td* is set for the drive shaft 26 based on the accelerator opening Acc and the vehicle speed V, the set required torque Td* is set as the torque command Tm* for the motor 32, and the switching control of transistors T11 to T16 of the inverter 34 is performed so that the motor 32 is driven by the torque command Tm*. In addition, in the electric vehicle 20 of this embodiment, when a system start operation (turning on the ignition switch 60) is performed, the positive side relay SB and the precharge relay SP are turned on to start precharging of the capacitor 35, and after the precharging is completed, the negative side relay SG is turned on and the precharge relay SP is turned off to set the system to ready-on, i.e., the system started state (a state in which the motor 32 and inverter 34 can be driven). Here, whether or not the precharging of the capacitor 35 is complete can be determined, for example, by determining whether or not the voltage Vc of the capacitor 35 from the voltage sensor 46a has reached a threshold Vref or higher, in which precharging is complete. The threshold Vref can be set to a value that is higher than the predetermined voltage Vcref and several tens of volts lower than the battery voltage Vb. Hereafter, this process may be referred to as the "normal startup process".

[0019] Next, we will describe the operation of the electric vehicle 20 in the embodiment configured in this way, in particular, the operation when detecting an increase in the contact resistance of the contact between the first positive terminal Tp1 and the second positive terminal Tp2 (first contact) and the contact between the first negative terminal Tn1 and the second negative terminal Tn2 (second contact) (hereinafter sometimes referred to as "terminal contacts"). Figure 2 is a flowchart of an example of a processing routine executed by the electronic control unit 50. This routine is executed when the system startup operation has been performed n times since the electric vehicle 20 started to be used, and once every m system startup operations (for example, 2, 3, 4, etc.) thereafter, instead of the normal startup process described above. Here, "n times" is the number of times it is estimated that the contact resistance of the first and second contacts will not increase, for example, 1 time, 2 times, 3 times, etc. m times is the timing at which the increase in contact resistance of the first and second contacts can be appropriately detected, for example, 2, 3, or 4 times. Note that this routine does not need to be executed every time the system startup operation is performed, and the normal startup process described above does not need to be performed. When the execution of the processing routine in Figure 2 begins, all relays of the relay device 48 (positive side relay SB, negative side relay SG, pre-charge relay SP) are turned off.

[0020] When this routine is executed, the CPU 52 of the electronic control unit 50 turns on the positive side relay SB and the precharge relay SP to start precharging the capacitor 35 (step S100). This precharging causes the voltage of the capacitor 35 to start rising.

[0021] Next, it is determined whether the elapsed time t1 since the start of precharging exceeds the determination time (predetermined time) tref1 (step S110). The determination time tref1 is a predetermined time that is the time at which the maximum value Imax of the inrush current Ir that flows when the negative side relay SG is turned on in step S120 becomes less than the smallest rated current among the rated current of the positive side relay SB, the rated current of the negative side relay SG, and the rated current of the capacitor 35. The inrush current Ir will be described later.

[0022] If time t1 does not exceed the determination time tref1, the system waits until time t1 exceeds the determination time tref1. When time t1 exceeds the determination time tref1, the negative side relay SG is turned on (step S120), and the maximum value Imax2 of the battery current Ib is input (step S130). Figure 3 is an explanatory diagram illustrating an example of the time changes of the capacitor voltage Vc, the battery current Ib, the state of the precharge relay SP, and the state of the negative side relay SG after precharging has started. When precharging starts (time t0), the voltage Vc starts to rise from a value of 0. Immediately after precharging starts, the current Ib rises sharply to a maximum value Imax1, but then gradually decreases. In this embodiment, the negative side relay SG is turned on when the voltage Vc exceeds a predetermined voltage Vcref (time t1). As a result, the current Ib increases sharply, and a large inrush current Ir flows in a very short time between the terminals (between the first positive terminal Tp1 and the first positive terminal Twhp1, between the second positive terminal Tp2 and the second positive terminal Twhp2, between the first negative terminal Tn1 and the first negative terminal Twhn1, and between the second negative terminal Tn2 and the second negative terminal Twhn2). In this embodiment, a predetermined voltage Vcref is set so that this inrush current Ir is less than or equal to the maximum value Imax1, and the time t1, which is the timing for turning on the negative terminal relay SG, is adjusted. The maximum value Imax2 is the maximum value of this inrush current Ir, and the maximum value of the battery current Ib detected by the current sensor attached to the output terminal of the battery 36 at a predetermined time tir, which is the time when the inrush current Ir flows after the negative terminal relay SG is turned on, is set.

[0023] Next, it is determined whether or not this is the nth system startup operation (step S140). If it is the nth startup operation, the maximum value Imax2 is set to the initial value Imaxinit and stored in the non-volatile memory 56 (step S140). Then, in the same process as the normal startup process, it is determined whether or not the pre-charging of capacitor 35 is complete (step S200). If the pre-charging of capacitor 35 is not complete, the system waits until the pre-charging is complete. When the pre-charging of capacitor 35 is complete, the pre-charge relay SP is turned off (step S210), the system is turned on, and the routine ends. Through this process, the maximum value Imax of the current Ib when the nth system startup operation is performed can be stored in the non-volatile memory 56 as the initial value Imaxinit.

[0024] If step S140 is not the nth system startup operation, that is, if it is the mth system startup operation from the nth time onward, the maximum value Imax2 entered in step S130 is subtracted from the initial position Imaxinit to calculate the decrease amount ΔImax (=Imaxinit-Imax) of the maximum value Imax of the current Ib (step S160), and it is determined whether the decrease amount ΔImax is less than the threshold (determined amount) DIref (step S170).

[0025] Here, we will explain the reason for calculating the decrease ΔImax. Figure 4 is an explanatory diagram showing an example of the relationship between the time change of the inrush current Ir and the magnitude of the contact resistance. In Figure 4, the contact resistance increases in the order of solid line, dashed line, and dashed line. The inrush current Ir can be calculated using the following equation (1). In equation (1), "Vb" is the voltage of battery 36, "Vc" is the voltage of capacitor 35, and "SR", "Rwhp", "Rwhn", "Rcp", "Rcn", "Rc", and "Rb" are the resistance values ​​of the limiting resistor SR, resistors Rwhp and Rwhn, the combined resistance of the contacts between the positive terminals (the contact between the first positive terminal Tp1 and the first positive terminal Twhp1, and the contact between the second positive terminal Tp2 and the second positive terminal Twhp2) (=Rcp1+Rcp2), the combined resistance of the contacts between the negative terminals (the contact between the first negative terminal Tn1 and the first negative terminal Twhn1, and the contact between the second negative terminal Tn2 and the second negative terminal Twhn2) (=Rcn1+Rcn2), resistor Rc, and resistor Rb, respectively. Since the resistance value of the limiting resistor SR is larger than the resistance values ​​of resistors Rwhp and Rwhn, the combined resistance of the contacts between the positive terminals, the combined resistance of the contacts between the negative terminals, and resistors Rc and Rb, when the negative terminal relay SG is turned on, most of the current from the battery 36 flows through the negative terminal relay SG without going through the precharge circuit SC. In other words, "SR" in equation (1) approaches the value of 0, and the inrush current Ir increases. As shown in equation (1) and Figure 4, the inrush current Ir becomes smaller when the resistance of the contacts between the terminals is large compared to when it is small, and the amplitude of the inrush current Ir also becomes smaller. Therefore, by examining the decrease ΔImax of the maximum value Imax2, it is possible to determine whether the contact resistance of at least one of the contacts between the connected terminals has increased, namely the contact between the first positive terminal Tp1 and the first positive terminal Twhp1, the contact between the second positive terminal Tp2 and the second positive terminal Twhp2, the contact between the first negative terminal Tn1 and the first negative terminal Twhn1, and the contact between the second negative terminal Tn2 and the second negative terminal Twhn2.

[0026] Ir=(Vb-Vc) / (SR+Rb+Rcp+Rwhp+Rc+Rcn+Rwhn) ···(1)

[0027] In step S170, the threshold DIref is a value determined by experiment, analysis, or machine learning as a threshold for determining whether or not the contact resistance is increasing. The threshold DIref may be set to a constant value. Also, since the decrease amount ΔImax is smaller when the capacitor 35 is deteriorating compared to when it is not, the threshold DIref may be set smaller when the capacitor 35 is deteriorating compared to when it is not. Furthermore, if the capacitance of the capacitor 35 increases at high temperatures (the maximum value Imax of the inrush current Ir increases), the threshold DIref may be set larger when the temperature of the capacitor 35 is high compared to when it is low. Also, if the capacitance of the capacitor 35 decreases at high temperatures (the maximum value Imax of the inrush current Ir decreases), the threshold DIref may be set smaller when the temperature of the capacitor 35 is high compared to when it is low.

[0028] In step S170, if the decrease amount ΔImax is less than the threshold DIref, it is determined that the contact resistance has increased (step S180). If the decrease amount ΔImax is greater than or equal to the threshold DIref, it is determined that the contact resistance has not increased (step S190). By using the decrease amount ΔImax in this way, it is possible to determine the increase in contact resistance between terminals after connecting them.

[0029] Next, in the same process as the normal startup process, it is determined whether or not the pre-charging of capacitor 35 is complete (step S200). If the pre-charging of capacitor 35 is not complete, the process waits until the pre-charging is complete. When the pre-charging of capacitor 35 is complete, the pre-charge relay SP is turned off (step S210), the system enters the ready-on state, and this routine ends. This process protects capacitor 35, the positive-side relay SB, and the negative-side relay SG while transitioning to the ready-on state, i.e., the system enters the ready-on state.

[0030] According to the electric vehicle 20 equipped with the power supply device of the embodiment described above, based on the current Ib of the battery 36 after precharging has started, it is determined whether the contact resistance of at least one of the following contacts has increased: the contact between the first positive terminal Tp1 and the first positive terminal Twhp1, the contact between the second positive terminal Tp2 and the second positive terminal Twhp2, the contact between the first negative terminal Tn1 and the first negative terminal Twhn1, and the contact between the second negative terminal Tn2 and the second negative terminal Twhn2. Therefore, it is possible to determine the increase in contact resistance between terminals after connecting the terminals.

[0031] Furthermore, by turning on the negative-side relay SG after a predetermined time (tref1) has elapsed since the start of precharging, and determining whether the contact resistance has increased based on the decrease ΔImax of the maximum value Imax2 of the current Ib after the negative-side relay SG has been turned on, it is possible to determine the increase in contact resistance between terminals with greater accuracy.

[0032] In the electric vehicle 20 equipped with the power supply unit of the embodiment, whether or not the contact resistance has increased is determined based on the decrease ΔImax of the maximum value Imax2 of the current Ib after the negative electrode relay SG is turned on. However, it is also possible to determine whether or not the contact resistance has increased based on the maximum value Imax2 of the current Ib (inrush current Ir) after the negative electrode relay SG is turned on. In this case, it is sufficient to determine that the contact resistance has increased when the maximum value Imax2 is less than a threshold (predetermined threshold) Ith.

[0033] In the electric vehicle 20 equipped with the power supply unit of the embodiment, whether or not the contact resistance has increased is determined based on the decrease amount ΔImax of the maximum value Imax2 of the current Ib after the negative electrode relay SG is turned on. However, as shown in Figure 5, an inrush current also flows when precharging is started, so when the above-described normal startup process is performed, whether or not the contact resistance has increased may be determined based on the decrease amount ΔImaxp of the maximum value Imax1 of the current Ib within a predetermined time after precharging has started (the value obtained by subtracting the maximum value Imax1 in a system startup operation after the nth time from the initial value as the maximum value Imax1 of the current Ib within a predetermined time after precharging has started when the system startup operation has been performed n times). In this case, it is sufficient to determine that the contact resistance has increased when the decrease amount ΔImaxp is less than a predetermined value DIrefp.

[0034] In the electric vehicle 20 equipped with the power supply unit of the embodiment, when the system is started, the negative-side relay SG is turned off and the positive-side relay SB and pre-charge relay SP are turned on to start pre-charging of the capacitor 356. However, as illustrated in the modified electric vehicle 120 of Figure 6, an additional pre-charge circuit SCa may be provided in the relay device 48, in which an additional limiting resistor SRa with a lower resistance value than the additional pre-charge relay SPa and limiting resistor SR is connected in series to bypass the negative-side relay SG. In this case, for example, at a predetermined time such as when inspecting or performing maintenance on the electric vehicle 20, the negative-side relay SG is turned off and the positive-side relay SB and additional pre-charge relay SPa are turned on to start additional pre-charging of the capacitor 35. After a determination time tref1 has elapsed since the start of additional pre-charging, the negative-side relay SG is turned on, and it may be determined whether the contact resistance has increased based on the maximum value Imax2 of the current Ib after the negative-side relay SG is turned on and the decrease amount ΔImax of the maximum value Imax2. Alternatively, it may be determined whether the contact resistance has increased based on the maximum value Imax1 of the current Ib immediately after the start of additional precharging, or the decrease in the maximum value Imax1, ΔImaxp. Since the additional limiting resistor SRa has a lower resistance value than the limiting resistor SR, a larger inrush current Ir flows when additional precharging is performed or when the negative electrode relay SG is subsequently turned off. Therefore, detection using a current sensor becomes easier, and it is possible to determine with greater accuracy whether the contact resistance has increased.

[0035] In electric vehicles 20 and 120 equipped with the power supply units of the embodiments and modifications, the precharge circuit SC and the additional precharge circuit SCa are connected to the negative-side relay SG, but they may also be connected to the positive-side relay SB. In this case, when starting the system, the positive-side relay SB should be turned off and the negative-side relay SG and the precharge relay SP or additional precharge relay SPa should be turned on to start precharging the capacitor 35, and after the determination time tref1 has elapsed since the start of precharging, the positive-side relay SB should be turned on.

[0036] In electric vehicles 20 and 120 equipped with the power supply devices of the embodiments and modifications, the power control unit PCU and the battery pack BP are connected via a wire harness WH. However, the first positive terminal Tp1 of the power control unit PCU and the second positive terminal Tp2 of the battery pack BP may be connected, and the first negative terminal Tn1 of the power control unit PCU and the second negative terminal Tn2 of the battery pack BP may be connected without using such a wire harness WH.

[0037] In electric vehicles 20 and 120 equipped with the power supply devices of the embodiments and modifications, the first positive terminals Tp1 and Twhp1, the first negative terminals Tn1 and Twhn1, the second positive terminals Tp2 and Twhp2, and the second negative terminals Tn2 and Twhn2 have metal parts formed by plating copper. However, the metal parts are not limited to those made of plated copper, but may be made of metals other than copper that have relatively high conductivity, or may not be plated at all.

[0038] The examples and modifications illustrate the application of the present invention to a power supply unit installed in an electric vehicle. However, the present invention may also be applied to other mobile vehicles such as automobiles, trains, and airplanes, or to power supply units installed in stationary power facilities.

[0039] Although embodiments for carrying out the present invention have been described above using examples, the present invention is not limited in any way to these embodiments, and can be carried out in various forms without departing from the spirit of the present invention. [Industrial applicability]

[0040] This invention can be used in industries such as the manufacturing of power supply devices. [Explanation of Symbols]

[0041] 20, 120 Electric vehicles, 35 Capacitors, 36 Batteries, 48 ​​Relay devices, 50 Electronic control units, Tn1, Twhn1 First negative terminal, Tn2, Twhn2 Second negative terminal, Tp1, Twhp1 First positive terminal, Tp2, Twhp2 Second positive terminal.

Claims

1. Power supply and Capacitors attached to the positive and negative terminal lines of the first power line, A relay device comprising a positive-side relay and a negative-side relay provided on the positive-side line and the negative-side line of the second power line from the power source, and a pre-charge circuit in which a pre-charge relay and a limiting resistor are connected in series to bypass the positive-side relay or the negative-side relay, A set of positive terminals connected to each other to connect the positive terminal line of the first power line and the positive terminal line of the second power line, A set of at least one pair of negative terminals connected to each other to connect the negative terminal line of the first power line and the negative terminal line of the second power line, A control device controls the positive-side relay, the negative-side relay, and the pre-charge relay so that when the system is started, it turns off one of the positive-side relay and the negative-side relay that bypasses the pre-charge relay and the limiting resistor, and turns on the other of the positive-side relay and the negative-side relay, and the pre-charge relay, so that the pre-charging of the capacitor begins. A power supply device comprising, The control device determines, based on the current of the power supply since the start of precharging, whether the contact resistance of at least one of the first contact, which is the contact between a pair of positive terminals, and the second contact, which is the contact between a pair of negative terminals, has increased. power supply.

2. A power supply device according to claim 1, The control device turns on one of the relays when a predetermined time has elapsed since the start of the pre-charge, and determines whether the contact resistance has increased based on the amount of decrease in the maximum current of the power supply when the one relay is turned on. power supply.

3. A power supply device according to claim 1, The control device turns on one of the relays when a predetermined time has elapsed since the start of the pre-charge, and determines that the contact resistance has increased when the current of the power supply falls below a predetermined threshold after the one relay is turned on. power supply.

4. A power supply device according to claim 1, The control device determines whether the contact resistance has increased based on the amount of decrease in the maximum current of the power supply when the pre-charge is started. power supply.

5. Power supply and Capacitors attached to the positive and negative terminal lines of the first power line, A relay device comprising a positive-side relay and a negative-side relay provided on the positive-side line and the negative-side line of the second power line from the power source, and a pre-charge circuit in which a pre-charge relay and a limiting resistor are connected in series to bypass the positive-side relay or the negative-side relay, A set of positive terminals connected to each other to connect the positive terminal line of the first power line and the positive terminal line of the second power line, A set of at least one pair of negative terminals connected to each other to connect the negative terminal line of the first power line and the negative terminal line of the second power line, A control device that, when starting the system, turns off one of the positive and negative relays that is bypassed by the precharge relay and the limiting resistor, and turns on the other of the positive and negative relays and the precharge relay to start precharging the capacitor, and after the precharging is complete, turns on the one relay and turns off the precharge relay to start the system, A power supply device comprising, The relay device has an additional precharge circuit in which an additional precharge relay and an additional limiting resistor with a resistance value smaller than the limiting resistor are connected in series to bypass the positive side relay or the negative side relay. The control device, at a predetermined time, turns off the relay that is bypassed by the additional precharge relay and the additional limiting resistor among the positive side relay and the negative side relay, and turns on the relay that is not bypassed by the additional precharge relay and the additional limiting resistor among the positive side relay and the negative side relay, and the additional precharge relay to start the additional precharge of the capacitor, and determines whether the contact resistance of at least one of the first contact, which is the contact between one pair of positive side terminals, and the second contact, which is the contact between one pair of negative side terminals, has increased, based on the current of the power supply after the start of the additional precharge, power supply.

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