JP2002281608A - Vehicle capacitor power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure safety by discharging a capacitor storage device during overhauling the capacitor storage device. SOLUTION: In this capacitor storage device 10 for vehicle, which comprises a motor functioning as a generator as the driving force, there are provided a plurality of serially-connected capacitor cells 30 to be charged with a motor, a bypass circuit 50 connected in parallel with respective capacitor cells (C1 to Cn), and a means of opening and closing respective bypass circuits. Before the start of maintenance, the respective capacitor cells (C1 to Cn) are discharged, by flowing discharged current through the bypass circuit 50. Each of the capacitor cells can be thereby discharged to 0 V. Accordingly, safety during maintenance is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a capacitor power storage device used for an electric vehicle or the like.

[0002]

2. Description of the Related Art In recent years, as a power storage device used for electric vehicles such as hybrid vehicles, it can be rapidly charged and discharged.
A power storage device (capacitor power storage device) using a long-life electric double layer capacitor (capacitor) as a storage battery has been developed.

In a capacitor power storage device, even if capacitors having the same rating are used, due to variations in capacitance, internal resistance, and leakage current, when charging and discharging are repeated, the shared voltage (cell voltage) of each capacitor connected in series is not affected. There is a problem that a balance occurs and some capacitors are overcharged and damaged. For this reason, a capacitor power storage device capable of uniformly charging each capacitor at the rated voltage is disclosed in, for example, Japanese Patent Application Laid-Open No. 6-343225.

[0004]

However, in this capacitor power storage device, when performing disassembly and maintenance, hot work is performed in the power storage state, and this does not solve the problem of safety. In particular, since the internal resistance of the capacitor is low,
There is a high risk of electric shock.

An object of the present invention is to ensure safety by discharging a capacitor power storage device when disassembling and maintaining the capacitor power storage device. Another object of the present invention is to provide a capacitor power storage device having a discharging function that does not deteriorate a capacitor due to reverse charging during discharging.

[0006]

Accordingly, a first aspect of the present invention is directed to a capacitor power storage device for a vehicle having a motor functioning as a generator as a driving force source, wherein a plurality of capacitors connected in series to be charged using the motor are provided. A cell, a bypass circuit connected in parallel to each capacitor cell, and means for opening and closing each bypass circuit, and discharging each capacitor cell by flowing a discharge current through the bypass circuit. And

According to a second aspect of the present invention, in the capacitor power storage device according to the first aspect, there is further provided means for detecting a shared voltage of each capacitor cell, and voltage control means for equalizing the shared voltage of each capacitor cell, The discharge of each capacitor cell is controlled using the voltage control means.

According to a third aspect, in the capacitor power storage device according to the second aspect, the voltage control means lowers the voltage of each capacitor cell by repeating discharge and interruption of discharge for each capacitor cell. It is characterized by.

A fourth invention is characterized in that the bypass circuit of the capacitor power storage device according to any one of the first to third inventions comprises a resistor and a transistor.

According to a fifth aspect, in the capacitor power storage device according to any one of the first to fourth aspects, discharge of each capacitor cell is started by turning on a switch provided in the vehicle. It is characterized by the following.

[0011]

According to the first aspect of the present invention, a bypass circuit is connected in parallel to each capacitor cell of the capacitor power storage device, and a discharge current is caused to flow through the bypass circuit at the start of maintenance, so that all the capacitor cells are reduced to 0V. Can be discharged. This ensures safety during maintenance.

In the second aspect, the capacitor power storage device includes voltage control means for equalizing the shared voltage of each capacitor cell. By controlling the discharge of each capacitor cell using the voltage control means, deterioration of the capacitor due to reverse charging can be prevented.

In the third aspect of the present invention, since the discharge and the interruption of the discharge are repeated, the voltage of each capacitor cell can be gradually lowered, so that the heat generation of the bypass circuit can be prevented.

According to the fourth aspect of the invention, the bypass circuit is composed of a resistor and a transistor, so that the weight of the bypass circuit can be reduced.

According to the fifth aspect of the present invention, the maintenance person can safely and easily start the discharge operation of the capacitor power storage device by turning on the switch.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hybrid system for a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG.

This hybrid system supplies electric power to a motor (motor generator) 1 which also functions as a generator, a driving inverter 2 for the motor generator 1, a hybrid electronic control unit (hybrid ECU) 3, and a vehicle electrical system (each on-vehicle device). Supply battery 4, maintenance switch
7. Equipped with a capacitor power storage device 10.

Motor generator 1 functions as a generator during deceleration operation of the vehicle, regenerates the inertial energy of the vehicle to generate power, and charges capacitor 30 in capacitor power storage device 10. Also, the motor generator 1
When the vehicle starts and accelerates, it functions as an electric motor using the capacitor power storage device 10 as a power source, and supplies driving torque to a driving system of the vehicle.

The hybrid ECU 3 performs overall control of the hybrid vehicle, and performs transmission of acquired vehicle information to each capacitor module 10 in the capacitor power storage device 10 in addition to engine control and motor generator control.

The maintenance switch 7 is turned on by a maintenance worker or the like when performing maintenance. When the maintenance switch 7 is turned on, the discharge control of the capacitor power storage device 10 is started. The ON / OFF signal of the maintenance switch 7 is a hybrid
It is detected by the ECU 3.

The plurality of capacitor power storage devices 10 (m
) Capacitor module 11 (MDL1 to MDLm), main circuit breaking contactor 14, main circuit fuse 15, total voltage detection amplifier 16, main circuit power line (+) 17, main circuit power line (-)
18. A communication network 21 is provided.

A plurality of capacitor modules 11 connected in series constitute a main power supply of a power supply system. The main circuit breaking contactor 14 extends from the capacitor module 11 to the inverter 2 by exciting and de-energizing the coil. Turns on / off the main circuit (high-voltage circuit). The main power supply may be configured by connecting the capacitor modules in series and parallel. The capacitor module 11 includes a plurality (n) of capacitor cells 30 connected in series and a voltage controller 40.
Consists of When the main circuit cut-off contactor 14 is turned on by turning on the key switch 5 and power from the main power supply is supplied to the inverter 2, the motor generator 1 is in a drivable state. When the key switch 5 is turned on, electric power is supplied from the battery 4 to each circuit such as the hybrid ECU 3.

Information on each capacitor module 11 is sequentially transmitted to the hybrid ECU 3 via the communication network 21. The hybrid ECU 3 sends various command signals and vehicle information to each capacitor module 11 via the communication network 21. Communication network 2
1 is provided with a terminating resistor 22.

The total voltage detection amplifier 16 converts the voltage of the main power supply (total voltage of the capacitor modules connected in series) into a total voltage signal insulated from the main circuit, and outputs the signal to the hybrid ECU.
Output to 3. The hybrid ECU 3 performs various determinations based on the total voltage signal and the like and issues various instructions to each module.

Next, a capacitor module according to an embodiment of the present invention will be described in detail with reference to FIG.

The capacitor module 11 comprises a plurality (n) of capacitor cells 30 (C1 to Cn) connected in series and a voltage controller 40. Each capacitor cell 30 may be constituted by one capacitor, or a plurality of capacitors connected in parallel may be regarded as one capacitor cell. As the capacitor, for example, a large-capacity electric double-layer capacitor is used.

The voltage controller 40 includes a bypass circuit 50 including a current limiting resistor 41 and a bypass transistor 42, an OR circuit 43, a comparator 44, a bypass reference voltage generating means 45, a cell voltage detection switching circuit 46, an isolation amplifier 47, and an AD. Conversion circuit 48, bypass switching circuit 4
9. Switching signal output circuit 51, data communication circuit 52, central processing unit (CPU) 53, read-only memory (ROM)
And a random access memory (RAM) 55.

The comparator 44 compares the shared voltage (cell voltage) of the capacitor cell with a fixed bypass reference voltage. When the shared voltage of the capacitor cell 30 becomes equal to or higher than the voltage set by the bypass reference voltage generating means 45 by charging, a bypass command is output. The bypass reference voltage is set near the withstand voltage of the capacitor cell (maximum usable voltage), for example, 2.7V. The bypass transistor 42 conducts the bypass circuit 50 when the base voltage is applied by the ON output of the OR circuit 43.
The bypass command turns on the bypass transistor 42 via the OR circuit 43 to bypass a part of the charging current of the capacitor cell. This bypass determination is made for each capacitor cell. In this manner, the voltage of each capacitor cell can be limited and equalized to the maximum usable voltage.

The voltage controller 40 of the capacitor power storage device according to the present invention includes not only the circuit for equalizing the maximum voltage but also a circuit for equalizing the cell voltage at an arbitrary voltage. Using this circuit, as described below,
Each capacitor cell can be discharged until the cell voltage becomes 0V.

The cell voltage switching circuit 46 includes an AD conversion circuit 4
In step 8, the target capacitor cell from which the voltage is read is sequentially switched based on a signal from the switching signal output circuit 51. From the AD conversion circuit 48, the digitized voltage signal is
It is taken into the CPU 53. At this time, the main power supply circuit including the capacitor cell and the AD conversion circuit 4
8 is insulated.

The CPU 53 performs discharge control when the maintenance switch is on. The discharge of each capacitor cell is performed by passing a discharge current through the bypass circuit 50.

The CPU 53 sends a switching signal to the bypass switching circuit 49 via the switching signal output circuit 51. Based on this switching signal, a bypass switching circuit 49
Outputs a bypass command to cells that need to be bypassed. The bypass command turns on the transistor 42 via the OR circuit 43 that takes an OR with the bypass command from the comparator 44.

As a result, the discharge current from the capacitor cell flows through the bypass circuit 50, and the static energy stored in the capacitor cell is consumed by the current limiting resistor 41 and the transistor 42. By the above-described bypass processing in which the current flows through the bypass circuit, the voltages of all the capacitor cells can be finally set to 0V.

When equalizing the cell voltage with an arbitrary voltage, the voltage controller 40 may, for example, bypass the charging current for a cell having a voltage higher than the average voltage by a predetermined value or more, so that the cell is charged during charging. Variation in cell voltage can be eliminated.

Hereinafter, a specific discharge control routine executed by the central processing unit CPU 53 in the voltage controller will be described with reference to the flowcharts of FIGS. This discharge control routine is executed by a program stored in the ROM 54.

First, a basic routine of the discharge control will be described with reference to FIG. This routine is executed at predetermined time intervals by timer interrupt processing or the like.

First, in step S1, the CPU 53
The on / off state of the maintenance switch 7 detected by the hybrid ECU 3 is acquired from the communication network 21. Next, in step S2, it is determined whether or not the maintenance switch 7 is on. If it is determined to be on, the discharge control in step S3 is performed, and then the process ends. When the maintenance switch 7 is off, the routine ends after the discharge control is ended.

Referring to FIG. 4, the subroutine relating to the discharge control in step S3 will be described.

First, in step S11, when starting to determine whether to discharge (bypass) the first to n-th capacitor cells (C1 to Cn), a variable i (1 (i ( Set 1 to n).

In step S12, it is determined whether the i-th capacitor cell is discharging. If discharging is being performed, the process proceeds to step S13, and it is determined whether the discharging state is continued for the specified time Td. If the discharge state has continued for the specified time Td, the routine proceeds to step S15. Step S
In 15, the CPU 53 stops discharging by turning off the bypass transistor 42. By continuing the discharge state for a short specified time Td, heat generation of the bypass circuit can be prevented. If the discharging state has not been continued for the specified time Td, the process proceeds to step S16, where the bypass transistor 42 is kept in the ON state, and the discharging is continued.

On the other hand, if the i-th capacitor cell is not discharging in step S12, the process proceeds to step S14, and it is determined whether or not the specified time Ts has elapsed since the discharge was stopped. If the specified time Ts has elapsed since the discharge was stopped, the routine proceeds to step S16. Step S16
, The CPU 53 turns on the bypass transistor 42 and starts discharging again. As described above, by setting the time interval for performing the bypass at a predetermined time Ts, the heat generation of the bypass circuit can be further suppressed. In step S14, if the specified time Ts has not elapsed since the stop of the discharge, the process proceeds to step S15, where the bypass transistor 42 is kept off, and the stop of the discharge is continued.

Next, in step S17, it is determined whether or not the discharge control of all cells has been completed (ie, whether i = n). When the discharge control of all cells has been completed, this routine ends. If the processing for all cells has not been completed, the process proceeds to step S18, where 1 is added to the variable i indicating the number of the capacitor cell, and the flow shifts to discharge control of the (i + 1) th cell.

As described above, the discharge is periodically performed (period Td + T
s), each capacitor cell is discharged slowly, and finally the cell voltage reaches 0 V, and the discharge ends.

FIG. 5 shows a state in which a discharge is performed by periodically turning on and off a bypass circuit (that is, a bypass transistor). First, when the maintenance switch is turned on, the bypass circuit starts to be turned on and off periodically. The voltage of the capacitor cell decreases when the bypass circuit is turned on, and becomes constant when the bypass circuit is turned off. The voltage of each capacitor cell gradually decreases to 0V.

As described above, the capacitor power storage device of the present invention has a function of discharging each capacitor cell when the maintenance switch 7 is turned on. Therefore, only by turning on the maintenance switch at the start of maintenance, the maintenance worker can easily discharge the capacitor power storage device, and safety during maintenance can be easily secured.

When an external discharge device is used, the entire capacitor power storage device is discharged.
When the cell is discharged up to a certain point, a cell having a reverse charge, that is, a negative voltage is generated due to variations in cell characteristics such as capacitance. However, in the capacitor power storage device according to the present invention, each cell discharges to a constant voltage of 0 V, and deterioration of the capacitor cell due to reverse charging does not occur. Discharging each cell to a constant voltage of 0 V is also effective for equalizing the shared voltage of the cell when recharging, and reduces variations during charging.

It should be noted that a switch to be turned on at the time of maintenance
Although the method of starting the discharge control has been described, a method of supplying power to the hybrid ECU and the capacitor power storage device in conjunction with this switch and performing the discharge control without using the key switch at the driver's seat may be employed. In this case, other control such as vehicle control and motor drive is not performed, and only the operation related to discharging of the capacitor power storage device is activated.

The present invention is not limited to the above embodiment. It is obvious that various changes can be made within the scope of the technical idea.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a hybrid system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a capacitor module of the capacitor power storage device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing a basic routine of discharge control.

FIG. 4 is a flowchart of a subroutine relating to discharge control.

FIG. 5 is a schematic diagram of discharge control.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 motor generator 2 inverter 3 hybrid ECU 7 maintenance switch 10 capacitor power storage device 11 capacitor module 21 communication network 30 capacitor cell 40 voltage controller 41 current limiting resistor 42 bypass transistor 45 bypass reference voltage generating means 46 cell voltage detection switching circuit 49 bypass switching Circuit 50 Bypass circuit 51 Switching signal output circuit 53 Central processing unit (CPU)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/02 H02J 7/02 H 7/14 7/14 H (72) Inventor Masakazu Sasaki Ageo, Saitama Nissan Diesel Industry Co., Ltd. (72) Inventor Shuichi Araki 1-1, Oji, Nissan Diesel Industry Co., Ltd. Ageo City, Saitama Prefecture 2-19-6 Okamura R & D Co., Ltd. F-term (reference) 3D035 AA05 5G003 AA07 BA04 CA11 CC04 FA06 GB06 GC05 5G060 AA04 BA08 CA12 DA01 DB01 DB02 DB07 5H115 PA08 PC06 PG04 PI14 PI29 PO02 PO17 PU08 PU25 PV09 PV23 QE01 QE08 QE QEQ QN03 QN12 SE06 TI01 TI05 TI06 TR19 TU04 TU16 TU17

Claims (5)

[Claims] 1. A capacitor power storage device for a vehicle having a motor functioning as a generator as a driving force source, comprising: a plurality of series-connected capacitor cells charged by using the motor; and a plurality of capacitor cells connected in parallel to each capacitor cell. And a means for opening and closing each bypass circuit, wherein each capacitor cell is discharged by supplying a discharge current to the bypass circuit at the start of maintenance. 2. A device for detecting a shared voltage of each capacitor cell, and a voltage control unit for equalizing the shared voltage of each capacitor cell, wherein discharge of each capacitor cell is controlled using the voltage control unit. The capacitor power storage device according to claim 1, wherein: 3. The capacitor power storage device according to claim 2, wherein said voltage control means performs control of repeating discharge and interruption of discharge for each capacitor cell. 4. The capacitor power storage device according to claim 1, wherein said bypass circuit comprises a resistor and a transistor. 5. The capacitor power storage device according to claim 1, wherein the discharge of each capacitor cell is started by turning on a switch provided in the vehicle.