JP2013074708A - Vehicular power unit and vehicle with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a discharge current to be equalized by equalizing batteries in a vehicle traveling state and to detect voltages of the batteries with high accuracy even if a line connecting an equalization circuit to the batteries is disconnected.SOLUTION: A vehicular power unit comprises a travel battery 1 which is configured by connecting in series a plurality of batteries 2, a voltage detection circuit 3 for detecting voltage of each of the batteries 2, and an equalization circuit 4 which discharges and equalizes the batteries 2. The equalization circuit 4 includes a discharge circuit 5 in which a discharge switch 6 and a discharge resistor 7 are connected in series. The discharge circuit 5 of the equalization circuit 4 is connected to each of the batteries 2 via a discharge line 8, and the voltage detection circuit 3 is connected to each of the batteries 2 via a voltage detection line 9. The discharge line 8 connects one terminal thereof to the battery 2 and connects the other terminal to the discharge circuit 5, and the voltage detection line 9 connects one terminal thereof to the battery 2 and connects the other terminal to the voltage detection circuit 3. The equalization circuit 4 discharges and equalizes the batteries 2 via the discharge line 8, and the voltage detection circuit 3 detects the voltage of each of the batteries 2 via the voltage detection line 9.

Description

  The present invention relates to a power supply device for a vehicle in which a large number of batteries are connected in series to increase the output voltage, and a vehicle including the power supply device.

  In order to increase the output of a power supply device for a vehicle, a large number of batteries are connected in series to increase the voltage. In this power supply device, batteries connected in series are charged with the same charging current and discharged with the same current. Therefore, if all the batteries have exactly the same characteristics, no imbalance occurs in the battery voltage or the remaining capacity. However, in reality, a battery having exactly the same characteristics cannot be manufactured. The battery imbalance is an imbalance of voltage and remaining capacity when charging and discharging are repeated. Furthermore, battery voltage imbalance causes overcharge or overdischarge of a specific battery. In order to prevent this adverse effect, a vehicle power supply device has been developed that detects the voltage of each battery and eliminates the imbalance (see Patent Document 1).

JP 2007-300701 A

  A power supply device for a vehicle described in Patent Document 1 includes a voltage detection circuit that detects each battery voltage that constitutes a battery for traveling, and a discharge circuit as an equalization circuit that equalizes the battery performance of each battery. I have. In this power supply device, a discharge circuit is connected in parallel with each battery constituting the traveling battery. The discharge circuit discharges a battery whose voltage has been increased to lower the voltage, thereby eliminating battery imbalance and equalizing battery characteristics.

  A voltage detection circuit and an equalization circuit of a conventional power supply apparatus are shown in FIG. The voltage detection circuit 93 connects the input side to each battery 92 in order to detect the voltage of each battery 92. Further, the equalization circuit 94 connects a discharge circuit 95 in which a discharge switch 96 and a discharge resistor 97 are connected in series to each battery 92 in parallel. This equalization circuit 94 switches on the discharge switch 96 of the discharge circuit 95 connected in parallel with the high voltage battery 92 to equalize the voltage of each battery 92. The equalization circuit 94 detects the voltage of each battery 92 by the voltage detection circuit 93 and controls the discharge switch 96 to be turned on and off by the control circuit 98. The control circuit 98 calculates the voltage signal of each battery 92 detected by the voltage detection circuit 93 and controls the discharge switch 96 on and off so as to equalize the voltage of each battery 92.

  Since the voltage detection circuit 93 and the equalization circuit 94 are connected to each battery 92, as shown in FIG. 1, the connection line 99 connecting the input side of the voltage detection circuit 93 to each battery 92 is Each discharge circuit 95 of the equalization circuit 94 is connected. This power supply apparatus has a drawback that the voltage of the battery 92 that is switching on the discharge switch 96 cannot be accurately detected in a state where the discharge switch 96 is switched on. This is because the discharge circuit 95 in the on state causes a current to flow through the connection line 99, and this current causes a voltage drop due to the electric resistance R of the connection line 99. The voltage drop of the connection line 99 is proportional to the product of the electrical resistance R of the connection line 99 and the discharge current I. The voltage drop in the connection line 99 reduces the voltage of the battery 92 and inputs it to the voltage detection circuit 93. Since the equalization circuit 94 turns on only a specific discharge switch 96 to generate an error, the voltage detection circuit 93 cannot accurately detect the voltages of all the batteries 92.

  Furthermore, as shown in FIG. 2, the above power supply apparatus has a drawback that the voltage detection circuit 93 detects the voltage of the battery 92 by mistake when any of the connection lines 99 is disconnected. As shown in FIG. 2, when the connection line L2 is disconnected and the discharge switches S1 and S2 connected to the connection line L2 are turned on, the voltage detection circuit 93 is connected to the voltages of the battery B1 and the battery B2. Cannot be detected accurately. This is because the voltage detection circuit 93 detects the voltages of the battery B1 and the battery B2 as a voltage divided by the discharge resistor 97. For example, if the voltage of the battery B1 is 3.5V and the voltage of the battery B2 is 2.5V, the discharge resistance 97 has the same electrical resistance, so the voltage detection circuit 93 sets the voltage of the battery B1 and the battery B2 to 3V. It will not be detected correctly.

  The present invention was developed for the purpose of eliminating the above-described drawbacks, and by realizing the equalization of the battery in the running state of the vehicle, the voltage and the remaining capacity can be efficiently equalized. A vehicle power supply device capable of detecting the voltage of each battery with extremely high accuracy even when a connection line connecting the discharge circuit of the equalization circuit to the battery is disconnected, and a vehicle including the power supply device are provided. There is.

Means for Solving the Problems and Effects of the Invention

  The power supply device for a vehicle according to the present invention includes a traveling battery 1 in which a plurality of rechargeable batteries 2 that supply electric power to a motor 11 that travels the vehicle are connected in series, and the traveling battery 1. A voltage detection circuit 3 for detecting the voltage of each battery 2 and an equalization circuit 4 for discharging the batteries 2 constituting the battery 1 for traveling to equalize the batteries 2 are provided. The equalization circuit 4 includes a discharge circuit 5 in which a discharge switch 6 and a discharge resistor 7 are connected in series. The discharge circuit 5 of the equalization circuit 4 is connected to each battery 2 via the discharge line 8. The voltage detection circuit 3 is connected to each battery 2 via a voltage detection line 9. The discharge line 8 has one end connected to the battery 2 and the other end connected to the discharge circuit 5. The voltage detection line 9 has one end connected to the battery 2 and the other end connected to the voltage detection circuit 3. The equalization circuit 4 discharges and equalizes the batteries 2 via the discharge lines 8, and the voltage detection circuit 3 detects the voltage of each battery 2 via the voltage detection lines 9.

  The power supply device described above has a feature that the voltage of each battery can be detected with extremely high accuracy while equalizing the batteries not only in a state where the key switch is turned off but also in a state where the vehicle is running. This is because the voltage of each battery can be accurately detected while the discharge switch is turned on and off while the vehicle is running with the key switch turned on and the batteries are equalized.

  Furthermore, the above power supply apparatus can detect the voltage of each battery even if the discharge line connecting the discharge circuit of the equalization circuit to the battery is disconnected. This is because a discharge line for discharging and equalizing the battery and a voltage detection line for detecting the voltage of the battery are provided separately as separate lines.

  In the vehicle power supply device of the present invention, the discharge line 8 and / or the voltage detection line 9 is connected to the electrode terminal 2A of the battery 2 via the metal terminal 30 by connecting the metal terminal 30 to one end. Can do.

  In the vehicle power supply device of the present invention, the metal terminal 30 can be fixed to the electrode terminal 2A by connecting to the electrode terminal 2A of the adjacent battery 2 so that the batteries 2 are connected in series.

  In the vehicle power supply device of the present invention, the equalization circuit 4 includes a control circuit 20 that controls the discharge switch 6 to be turned on and off. The control circuit 20 detects the voltage of each battery 2 detected by the voltage detection circuit 3. Accordingly, the batteries 2 can be equalized by controlling the discharge switches 6 on and off accordingly.

  In the power supply device for a vehicle according to the present invention, the control circuit 20 can control the discharge switch 6 to be turned on and off depending on the off state and the on state of the key switch 15 of the vehicle to equalize the batteries 2.

  A vehicle according to the present invention includes any one of the power supply devices described above.

It is a block diagram of the voltage detection circuit and equalization circuit of the conventional power supply device for vehicles. FIG. 2 is a block diagram illustrating a state in which a connection line between a voltage detection circuit and an equalization circuit illustrated in FIG. 1 is disconnected. It is a block diagram of the power supply device for vehicles concerning one example of the present invention. It is a perspective view which shows an example of the connection structure of the electrode terminal of a battery, a voltage detection line, and a discharge line. It is a disassembled perspective view which shows the connection structure of the electrode terminal of the battery shown in FIG. 4, a voltage detection line, and a discharge line. It is a block diagram which shows the example which mounts a power supply device in the hybrid vehicle which drive | works with an engine and a motor. It is a block diagram which shows the example which mounts a power supply device in the electric vehicle which drive | works only with a motor.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment shown below exemplifies a power supply device for a vehicle for embodying the technical idea of the present invention and a vehicle including this power supply device. Vehicles equipped with a power supply device are not specified as follows. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

As shown in the block diagram of FIG. 3, the power supply device for a vehicle includes a traveling battery 1 in which a plurality of rechargeable batteries 2 that supply power to a motor 11 that travels the vehicle are connected in series, and the traveling battery 1. The battery 2 constituting the battery 1 is connected to the battery 2 via the voltage detection line 9, and the voltage detection circuit 3 for detecting the voltage of each battery 2 and the battery 2 constituting the battery 1 for traveling are discharged to each And an equalizing circuit 4 for equalizing the batteries 2.
Although not shown, the battery constituting the traveling battery may include a battery connected in parallel, and in this case, a battery in which a plurality of batteries are connected in parallel is a unit battery. The battery module is configured by connecting the battery modules in series as the battery 2 in the above embodiment.

  Further, the power supply device shown in the block diagram of FIG. 3 has a contactor 16 connected to the output side of the traveling battery 1. Via this contactor 16, the traveling battery 1 is connected to a DC / AC inverter 10 that is a load on the vehicle side. The DC / AC inverter 10 is connected to a motor 11 that travels the vehicle and a generator 12 that charges the traveling battery 1. The DC / AC inverter 10 is controlled by the control unit 14. The control unit 14 supplies the power of the traveling battery 1 to the traveling motor 11 via the DC / AC inverter 10 to cause the vehicle to travel with the motor 11. Further, the generator 12 is controlled to charge the traveling battery 1 with the generator 12.

  Further, the control unit 14 is connected to a key switch 15 and switches the contactor 16 on and off by a signal input from the key switch 15. When the key switch 15 is switched on, the control unit 14 switches the contactor 16 on. However, the control unit 14 switches the contactor 16 from OFF to ON after the initial operation check is completed after the key switch 15 is turned ON, and connects the traveling battery 1 to the DC / AC inverter 10. . When the key switch 15 is switched off, the control unit 14 switches the contactor 16 off and disconnects the traveling battery 1 from the DC / AC inverter 10.

  The battery 2 constituting the traveling battery 1 is a single secondary battery or a plurality of secondary batteries connected in series. The battery 2 of the traveling battery 1 is a lithium ion battery or a lithium polymer battery. The battery 1 for driving | running | working which uses a lithium ion battery or a lithium polymer battery as a secondary battery comprises the battery 2 with one secondary battery. In this power supply device, the voltage detection circuit 3 detects the voltage of each battery 2, and the equalization circuit 4 equalizes each battery 2. However, the battery can be any rechargeable secondary battery such as a nickel metal hydride battery. A power supply device using nickel-metal hydride batteries as a battery connects a plurality of secondary batteries in series to form a single battery, and detects the voltage of each battery, that is, a battery in which a plurality of secondary batteries are connected in series. Also, equalize this battery.

  The voltage detection circuit 3 connects the input side to the positive and negative terminals of each battery 2 via the voltage detection line 9. The voltage detection circuit 3 detects the voltage of each battery 2 via the voltage detection line 9. The voltage detection line 9 has one end connected to the electrode terminal of the battery 2 and the other end connected to the input side of the voltage detection circuit 3.

  The equalization circuit 4 equalizes the cell voltage of the battery 2 by eliminating the imbalance. The equalization circuit 4 detects the voltage of each battery 2 and cancels the voltage imbalance of each battery 2 to equalize. The equalization circuit 4 equalizes the battery 2 not only in the off state of the key switch 15, that is, in the state in which the vehicle is stopped, but also in the state in which the vehicle can run with the key switch 15 in the on state. However, after all the batteries 2 are equalized, the equalization circuit 4 stops operating.

  As shown in FIG. 3, the equalization circuit 4 discharges the battery 2 having a high voltage with the discharge resistor 7 to eliminate the imbalance. 3 includes a discharge circuit 5 in which a discharge switch 6 is connected in series to a discharge resistor 7, and a control circuit 20 that controls the discharge switch 6 to be turned on and off. Since the discharge circuit 5 discharges and equalizes each battery 2 independently, the same number as the number of the batteries 2, for example, in a power supply device in which 100 batteries 2 are connected in series, 100 sets of discharge circuits are provided. A discharge switch 6 and a discharge resistor 7 constituting each discharge circuit 5 are mounted on a circuit board (not shown), and each battery 2 is connected via a discharge line 8 provided as a separate line from the voltage detection line 9. Connected to. The discharge line 8 has one end connected to the electrode terminal of the battery 2 and the other end connected to the discharge circuit 5.

  The voltage detection line 9 and the discharge line 8 are connected to each battery 2 through a metal terminal connected to the electrode terminal of the battery 2. As shown in FIGS. 4 and 5, the battery 2 has a metal terminal 30 connected to the electrode terminal 2 </ b> A in order to connect the voltage detection line 9 and the discharge line 8 separately and independently. The metal terminal 30 is laser-welded and connected to the electrode terminal 2A of the battery 2, or is connected to the electrode terminal with a nut or a set screw (not shown). The metal terminals 30 in FIGS. 4 and 5 are used together with a metal plate bus bar 17 that connects adjacent batteries 2 in series or in parallel. The bus bar 17 in these figures is provided with a protruding terminal portion 31 that connects the voltage detection line 9 and the discharge line 8. The terminal portion 31 is provided with a female screw hole 32. The voltage detection line 9 and the discharge line 8 are connected to a terminal portion 31 provided on the bus bar 17 that is a metal terminal 30. In the voltage detection line 9 and the discharge line 8 shown in the drawing, a connection terminal 34 is connected to the tip of the lead wire 33. The connection terminal 34 is crimped to connect the lead wire 33. The connection terminal 34 to which the lead wire 33 is connected by crimping can be more securely electrically connected by soldering the connection portion. The connection terminal 34 has a through hole 35, and a set screw 36 inserted into the through hole 35 is screwed into the female screw hole 32 of the terminal portion 31 to fix the voltage detection line 9 and the discharge line 8 to the bus bar 17. . The connection terminal 34 is connected to the metal terminal 30 with a set screw 36. However, the connection terminal can be spot welded or laser welded to be connected to the bus bar of the metal terminal.

  The equalization circuit 4 includes a control circuit 20 that controls the discharge switch 6 to be turned on / off by the voltage of the battery 2. The control circuit 20 in FIG. 3 controls each discharge switch 6 to be turned on / off by the voltage of the battery 2 detected by the voltage detection circuit 3. The equalization circuit 4 uses the voltage detection circuit 3 in combination with a circuit that detects the voltage of the battery 2. However, the equalization circuit can also be provided with a dedicated voltage detection circuit for detecting the battery voltage.

  The control circuit 20 compares the voltages of the batteries 2 detected by the voltage detection circuit 3 and controls the discharge switches 6 so as to equalize the voltages of all the batteries 2. The control circuit 20 turns on the discharge switch 6 of the discharge circuit 5 connected to the battery 2 that is too high to discharge. The voltage of the battery 2 decreases as it discharges. The discharge switch 6 is switched from on to off when the voltage of the battery 2 decreases until it balances with the other batteries 2. When the discharge switch 6 is turned off, the discharge of the battery 2 is stopped. Thus, the control circuit 20 discharges the high voltage battery 2 and balances the voltages of all the batteries 2.

  As described above, the power supply device for a vehicle accurately detects the voltage of each battery 2 while equalizing the batteries 2 of the traveling battery 1.

  In the power supply device of the above embodiment, the voltage detection circuit 3 for detecting the voltage of each battery 2 constituting the traveling battery 1 and the discharge switch 6 of the discharge circuit 5 provided in the equalization circuit 4 are controlled to be turned on and off. The control circuit 20 is a separate circuit. However, the power supply device can also be made into one chip with the voltage detection circuit and the control circuit as an ASIC. In this power supply device, the one-chip ASIC detects the voltage of each battery of the traveling battery, and controls the discharge switch on and off according to the detected voltage of each battery to turn on each battery. Equalize.

  In the above embodiment, since the discharge line 8 for discharging and equalizing the battery 2 and the voltage detection line 9 for detecting the voltage of the battery 2 are separately provided as separate lines, the discharge circuit of the equalization circuit 4 is provided. Even if the discharge line 8 connecting 5 to the battery 2 is disconnected, the voltage of each battery 2 can be detected.

  Furthermore, since the batteries 2 can be equalized even when the vehicle is running, the time period during which the batteries 2 can be equalized can be lengthened. As a result, it is possible to equalize the batteries 2 while reducing the discharge current that equalizes the batteries 2. This is extremely important for equalization of a traveling battery composed of a large number of batteries. This is because when the discharge current for equalizing the batteries increases and the amount of heat generated by the discharge resistors increases, a large number of discharge resistors generate heat while discharging a large number of batteries, and the total amount of heat generated becomes extremely large. . Moreover, the fact that the amount of heat generated by the discharge resistor can be reduced makes it possible to make the discharge resistor extremely small, and also realizes the feature that a large number of discharge resistors can be arranged in a small space.

  The above power supply apparatus can be used as a vehicle-mounted power supply. As a vehicle equipped with a power supply device, an electric vehicle such as a hybrid vehicle or a plug-in hybrid vehicle that runs with both an engine and a motor, or an electric vehicle that runs only with a motor can be used, and is used as a power source for these vehicles. .

(Power supply device for hybrid vehicles)
FIG. 6 shows an example in which a power supply device is mounted on a hybrid vehicle that runs with both an engine and a motor. A vehicle HV equipped with the power supply device 100 shown in this figure includes an engine 13 for traveling the vehicle HV, a motor 11 for traveling, a power supply device 100 that supplies power to the motor 11, and power generation for charging a battery of the power supply device 100. Machine 12. The power supply device 100 is connected to the motor 11 and the generator 12 via the DC / AC inverter 10. The vehicle HV travels by both the motor 11 and the engine 13 while charging / discharging the battery of the power supply device 100. The motor 11 is driven to drive the vehicle when the engine efficiency is low, for example, when accelerating or traveling at a low speed. The motor 11 is driven by power supplied from the power supply device 100. The generator 12 is driven by the engine 13 or is driven by regenerative braking when the vehicle is braked to charge the battery of the power supply device 100.

(Power supply for electric vehicles)
FIG. 7 shows an example in which a power supply device is mounted on an electric vehicle that runs only with a motor. A vehicle EV equipped with the power supply device 100 shown in this figure includes a traveling motor 11 that travels the vehicle EV, a power supply device 100 that supplies power to the motor 11, and a generator that charges a battery of the power supply device 100. 12. The power supply device 100 is connected to the motor 11 and the generator 12 via the DC / AC inverter 10. The motor 11 is driven by power supplied from the power supply device 100. The generator 12 is driven by energy when regeneratively braking the vehicle EV and charges the battery of the power supply device 100.

  In particular, when a power supply device is mounted on an electric vehicle, the capacity of the power supply device is larger than that of a hybrid vehicle, so that the unbalance of the power supply device, that is, the battery 2 constituting the traveling battery 1 is increased. Therefore, in order to make it possible to eliminate the imbalance more greatly in the same time, it is necessary to decrease the value of the discharge resistor 7 and increase the discharge current flowing through the discharge line 8. In this configuration, the wiring resistance The influence of the voltage drop due to the above also becomes large. In the above embodiment, since the discharge line 8 connected to the discharge circuit 5 and the voltage detection line 9 connected to the voltage detection circuit 3 are separately provided as separate lines, the discharge current is the voltage detection line 8. Does not flow. Therefore, the voltage of the battery 2 can be accurately detected even while the equalization circuit 4 is equalizing the battery 2.

  The power supply device for a vehicle according to the present invention can be suitably used as a power supply device for a vehicle such as a plug-in hybrid electric vehicle, a hybrid electric vehicle, or an electric vehicle that can switch between the EV traveling mode and the HEV traveling mode.

DESCRIPTION OF SYMBOLS 100 ... Power supply device 1 ... Battery for driving | running | working 2 ... Battery 2A ... Electrode terminal 3 ... Voltage detection circuit 4 ... Equalization circuit 5 ... Discharge circuit 6 ... Discharge switch 7 ... Discharge resistor 8 ... Discharge line 9 ... Voltage detection line 10 ... DC / AC inverter 11 ... motor 12 ... generator 13 ... engine 14 ... control unit 15 ... key switch 16 ... contactor 17 ... bus bar 20 ... control circuit 30 ... metal terminal 31 ... terminal portion 32 ... female screw hole 33 ... lead wire 34 ... connection Terminal 35 ... Through hole 36 ... Set screw 92 ... Battery 93 ... Voltage detection circuit 94 ... Equalization circuit 95 ... Discharge circuit 96 ... Discharge switch 97 ... Discharge resistor 98 ... Control circuit 99 ... Connection line HV ... Vehicle EV ... Vehicle

Claims (6)

A battery for traveling (1) formed by connecting a plurality of rechargeable batteries (2) for supplying electric power to a motor (11) for running the vehicle, and each of the batteries constituting the traveling battery (1) A voltage detection circuit (3) for detecting the voltage of the battery (2) and an equalization circuit (4) for discharging the battery (2) constituting the traveling battery (1) to equalize each battery (2) ) And
The equalization circuit (4) includes a discharge circuit (5) in which a discharge switch (6) and a discharge resistor (7) are connected in series,
A discharge circuit (5) of the equalization circuit (4) is connected to each battery (2) via a discharge line (8), and the voltage detection circuit (3) is connected via a voltage detection line (9). Connected to each battery (2)
The discharge line (8) has one end connected to the battery (2) and the other end connected to the discharge circuit (5),
The voltage detection line (9) has one end connected to the battery (2) and the other end connected to the voltage detection circuit (3),
The equalization circuit (4) discharges and equalizes the battery (2) via the discharge line (8), and the voltage detection circuit (3) passes through each voltage (9) via the voltage detection line (9). A vehicle power supply device configured to detect the voltage of 2).   The discharge line (8) and / or the voltage detection line (9) is connected to a metal terminal (30) at one end, and through the metal terminal (30), the electrode terminal ( The power supply device for vehicles according to claim 1 connected to 2A).   The metal terminal (30) is connected to the electrode terminal (2A) of an adjacent battery (2) and fixed to the electrode terminal (2A) so as to connect the battery (2) in series. The power supply device for vehicles described in 2.   The equalization circuit (4) includes a control circuit (20) for controlling the discharge switch (6) to be turned on and off, and the control circuit (20) is configured to detect each battery (3) detected by the voltage detection circuit (3). 4. The vehicle power supply device according to claim 1, wherein each of the batteries (2) is equalized by controlling the discharge switch (6) on and off according to the voltage of 2). 5.   5. The control circuit (20) controls the discharge switch (6) to be turned on and off according to an off state and an on state of a key switch (15) of a vehicle to equalize each battery (2). The vehicle power supply described.   A vehicle comprising the power supply device according to claim 1.

Images