JP5004742B2 - Power supply - Google Patents

Description

  The present invention relates to a power supply apparatus that is optimal for a hybrid car and that supplies power from a high-voltage battery to a load.

  In a power supply device including a high voltage battery, a plurality of rechargeable batteries are connected in series to increase the output voltage. Since this power supply device has a high output voltage, it is important to prevent an electric shock accident. In order to realize this, a power supply device that does not connect a high voltage battery to chassis ground has been developed. (See Patent Document 1)

A power supply device in which a large number of batteries are connected in series can be charged and discharged while preventing overcharge and overdischarge of the battery, thereby extending the life of the battery. In order to realize this, the power supply device including the high voltage battery 81 illustrated in FIG. 1 includes a voltage detection circuit 83 that detects the voltage of the battery 82. The voltage detection circuit 83 has an electrostatic absorption capacitor 86 connected to the chassis ground 91 on the input side. This is to prevent a high voltage due to static electricity being input to the input side and the electronic circuit from being damaged. In particular, recent voltage detection circuits use an FET as a semiconductor element on the input side, so that the input impedance is extremely high, and an extremely high voltage is input to the input side due to static electricity, causing the FET to be destroyed. The electrostatic absorption capacitor 86 connected to the input side absorbs high voltage due to static electricity and prevents high voltage static electricity from being input to the input side of the FET.
JP 2005-295698 A

  The voltage detection circuit 83 in which the electrostatic absorption capacitor 86 is connected to the input side has a drawback that the voltage of the battery 82 cannot be accurately detected while being connected to the load 90. This is because the capacitor 95 connected to the load 90 side is charged and discharged as shown by the chain line A in FIG.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to ensure the safety of electric shock caused by a high voltage battery, further to prevent failure of the voltage detection circuit due to static electricity, and even if the capacitor connected to the load side is charged / discharged, the voltage detection circuit Is to provide a power supply device that can accurately detect the voltage of a battery.

The power supply device of the present invention has the following configuration in order to achieve the above-described object.
The power supply device is supplied with power from a high voltage battery 1 in which a plurality of rechargeable batteries 2 are connected in series, a voltage detection circuit 3 that detects the voltage of the high voltage battery 1, and the high voltage battery 1. A metal case 4 containing the load 20, the high-voltage battery 1 and the voltage detection circuit 3 and connected to the chassis earth 21 of the load 20, and the metal case 4 and the ground line 5 of the voltage detection circuit 3 And an electrostatic absorption capacitor 6 connected therebetween. Further, the power supply device includes a disconnect switch 7 connected in series with the electrostatic absorption capacitor 6. The electrostatic absorption capacitor 6 absorbs static electricity when the disconnect switch 7 is closed, and voltage detection is performed when the disconnect switch 7 is open. Circuit 3 detects the voltage of high voltage battery 1.

  The power supply apparatus according to claim 2 of the present invention uses the disconnect switch 7 as a switch that can be mechanically switched between a closed state and an open state. Furthermore, the power supply device according to claim 3 of the present invention uses the disconnect switch 7 as a switch that can be switched to an open state when the load 20 is turned on. Furthermore, the power supply device according to claim 4 of the present invention uses the disconnect switch 7 as a switch that is set on the load 20 side and switched to the open state. Furthermore, in the power supply device according to claim 5 of the present invention, the disconnect switch 7 is a switch that cannot be operated from the outside while being set in the load 20.

  In the power supply device according to claim 6 of the present invention, the load 20 connected to the high-voltage battery 1 is an inverter 22 that connects the vehicle running motor 23 and the generator 24 on the secondary side.

  The power supply device of the present invention prevents the failure due to static electricity of the voltage detection circuit while ensuring the safety due to the electric shock by the high voltage battery, and further, the battery voltage of the voltage detection circuit by charging and discharging of the capacitor connected to the load side. Detection error can be prevented. This is because the power supply device of the present invention connects a series circuit of an electrostatic absorption capacitor and an isolation switch between the ground line of the voltage detection circuit and the metal case, and absorbs static electricity with the electrostatic absorption capacitor in the closed state of the isolation switch. This is because the voltage detection circuit detects the voltage of the high voltage battery with the disconnect switch open.

  In the power supply device having the above structure, the separation switch is closed in an assembly process before being mounted on a vehicle or the like as a load. In this state, the ground line is connected to the metal case via an electrostatic absorption capacitor. In the assembly process, the metal case is not always connected to a grounded earth. This is because, for example, the metal case is conveyed by a rubber belt conveyor which is an insulating material, or is assembled on a work table which is not grounded. Therefore, a high voltage due to static electricity may be applied to a metal case, an input / output terminal, or the like in a process before being mounted on a vehicle or the like. Static electricity is extremely high at several thousand volts or more, and is a voltage that destroys electronic components such as a voltage detection circuit. In the power supply device of the present invention, the electrostatic absorption capacitor connected between the metal case and the ground line absorbs the high voltage due to the static electricity. This is because the electrostatic absorption capacitor is connected between the ground line and the metal case with the separation switch closed.

  In a state where the metal case is mounted on a vehicle or the like as a load, the disconnect switch is in an open state. In this state, the metal case is connected to the chassis earth of the vehicle. When the metal case is connected to the chassis ground, a high voltage due to static electricity is not applied to the metal case. Further, a connector is also connected to the input / output terminals, and a high voltage due to static electricity is not applied thereto. Therefore, when the metal case is mounted on the load side, the voltage detection circuit does not fail due to static electricity. Further, in this state, since the electrostatic absorption capacitor is not connected to the metal case with the ground line, the electrostatic absorption capacitor is not charged or discharged even if the potential of the metal case and the chassis ground changes due to charge / discharge on the load side. Therefore, the voltage detection circuit can accurately detect the voltage of the battery without any detection error due to charging / discharging of the electrostatic absorption capacitor.

  Furthermore, the power supply device according to claim 2 of the present invention is a switch that can be mechanically switched between an open state and a closed state in addition to the configuration of claim 1. Until this power supply device is mounted on the load side, the disconnect switch is in the closed state, mounted on the load side and the disconnect switch is in the open state, while preventing failure of the voltage detection circuit due to high voltage due to static electricity, The voltage detection circuit can accurately detect the battery voltage.

  According to a third aspect of the present invention, in addition to the configuration of the first aspect, the disconnection switch is a switch that can be switched to a closed state when the load side is turned on. This power supply device keeps the disconnect switch closed until the metal case is mounted on the load side, thereby preventing the voltage detection circuit from being damaged due to static electricity. When the power is turned on after being mounted on the load side, the disconnect switch is closed, and the voltage detection circuit accurately detects the battery voltage.

  Furthermore, the power supply device according to claim 4 of the present invention is configured so that, in addition to the configuration of claim 1, the disconnection switch is a switch that is set on the load side and switched to the open state. In this power supply, the disconnect switch is in the closed state until the metal case is set on the load side to prevent adverse effects due to static electricity. In the state where the metal case is set on the load side, the disconnect switch is switched to the open state. The detection error due to charging / discharging of the electrostatic absorption capacitor of the voltage detection circuit is eliminated, and the battery voltage is accurately detected.

  In addition to the configuration of claim 1, the power supply device according to claim 5 of the present invention is a switch that cannot be operated from the outside while being set on the load, so that the disconnect switch is set on the assembly process or load side. In this state, the user or operator will not accidentally switch the disconnect switch.

  Furthermore, in the power supply device according to claim 6 of the present invention, in addition to the configuration of claim 1, a load connected to the high voltage battery is connected to the secondary side of the vehicle running motor and the generator. Inverter. In this power supply device, the voltage detection circuit can accurately detect the voltage of the battery even when the high-voltage battery is charged / discharged via the traveling motor or the generator and the potential of the chassis ground fluctuates.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below exemplify a power supply device for embodying the technical idea of the present invention, and the present invention does not specify the power supply device 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.

  The power supply device shown in FIG. 2 includes a high voltage battery 1 in which a plurality of rechargeable batteries 2 are connected in series, a voltage detection circuit 3 that detects the voltage of the high voltage battery 1, and power from the high voltage battery 1. , A metal case 4 containing the high-voltage battery 1 and the voltage detection circuit 3 and connected to the chassis earth 21 of the load 20, and the ground of the metal case 4 and the voltage detection circuit 3. An electrostatic absorption capacitor 6 connected to the line 5 is provided. This power supply apparatus is mainly mounted on a vehicle such as a hybrid car, a fuel cell car, and an electric car. A power supply device mounted on the vehicle connects an inverter 22 to a load 20. The inverter 22 has a primary side connected to the high voltage battery 1 via the contactor 9 and a secondary side connected to the traveling motor 23 and the generator 24. The power supply device of FIG. 2 is mounted on a vehicle using the load 20 as an inverter 22, but can also be used for applications other than the vehicle.

  The power supply device mounted on the vehicle supplies power from the high voltage battery 1 to the travel motor 23 via the inverter 22. In this state, the high voltage battery 1 is discharged. The inverter 22 converts the direct current of the high voltage battery 1 into alternating current and supplies it to the traveling motor 23. The inverter 22 can also increase the voltage of the high voltage battery 1 and supply it to the traveling motor 23. Further, the inverter 22 supplies power from the secondary side to the primary side, and supplies the power of the generator 24 to the high voltage battery 1. In this state, the high voltage battery 1 is charged. In the inverter 22, the midpoint of the capacitor 25 connected in series is connected to the chassis ground 21. The potential of the middle point of the capacitor 25 varies as the high voltage battery 1 is charged and discharged.

  The voltage detection circuit 3 detects the voltage at the connection point 10 of the series-connected batteries 2 constituting the high-voltage battery 1 or detects the total voltage of the high-voltage battery 1. The voltage detection circuit 3 includes a multiplexer 11 and an A / D converter 12. The multiplexer 11 switches the connection point 10 at a constant cycle and outputs it to the A / D converter 12. The A / D converter 12 converts the input analog signal at the connection point 10 into a digital signal and outputs it. A digital signal output from the A / D converter 12 is input to the control circuit 13. The control circuit 13 detects the voltage of the battery 2 from the input digital signal, and controls the charge / discharge current from the detected voltage of the battery 2 so as to prevent the overvoltage and overdischarge of the high voltage battery 1.

  An input capacitor 8 is connected to each input side of the voltage detection circuit 3 of FIG. The input capacitor 8 is connected between the input side and the ground line 5. The voltage detection circuit 3 can prevent a high voltage due to static electricity from being input to the input terminal while connecting the input resistor 14 having a high resistance to the input terminal to increase the impedance of the line. The input capacitor can be connected to the input side of the A / D converter or the input side of the control circuit. Even if high-voltage static electricity is applied to the input side, the input capacitor 8 can absorb this and prevent failure due to static electricity. However, in a circuit with low impedance on the input side or low impedance on the output side connected to the input side, it is not always necessary to connect the input capacitor. This is because static electricity is short-circuited by a low impedance circuit and a high voltage is not applied.

  The voltage detection circuit 3 operates using the high voltage battery 1 as a power source, or operates using a low voltage battery supplied from the load 20 side as a power source (not shown). The low voltage battery is a battery for electrical equipment mounted on a vehicle. The power source of the battery for electrical equipment that supplies power to the voltage detection circuit is insulated from the chassis ground of the battery for electrical equipment and outputs the power supply voltage to the voltage detection circuit. The insulation type power supply circuit can be configured such that the negative line of the battery for electrical equipment is connected to the chassis ground while the ground line of the voltage detection circuit is not connected to the chassis ground of the load.

  The voltage detection circuit 3 does not connect the ground line 5 to the metal case 4. The ground line 5 of the voltage detection circuit 3 is connected to the metal case 4 through a series circuit of the electrostatic absorption capacitor 6 and the disconnect switch 7. The electrostatic absorption capacitor 6 is a capacitor that absorbs static electricity, for example, 0.1 μF to 0.001 μF.

  The disconnect switch 7 prevents an adverse effect due to static electricity in the closed state, and the voltage detection circuit 3 accurately detects the voltage of the battery 2 in the open state. Defects caused by static electricity occur before the metal case 4 is set in a vehicle having a load 20. This is because the metal case 4 is not connected to the chassis earth 21 to the load 20. Accordingly, the disconnect switch 7 is in a closed state when not set on the load 20 side to prevent adverse effects due to static electricity. When the metal case 4 is set in the vehicle on the load 20 side, no adverse effect due to static electricity occurs. This is because the metal case 4 is connected to the chassis ground 21. Accordingly, the disconnect switch 7 is opened in a state where the metal case 4 is set on the load 20 side. When the disconnect switch 7 is in an open state, the electrostatic absorption capacitor 6 is disconnected from the ground line 5. Therefore, the current for charging / discharging the electrostatic absorption capacitor 6 does not cause a battery voltage detection error of the voltage detection circuit 3. That is, the voltage detection circuit 3 accurately detects the voltage of the battery 2.

  The separation switch 7 is a switch that can be mechanically switched between a closed state and an open state, that is, a switch that can be turned on and off. The separation switch 7 is turned on until the metal case 4 is set on the vehicle on the load 20 side, and is turned off after being set on the vehicle. The disconnect switch 7 is a switch that cannot be operated from the outside while being set to the load 20, thereby preventing a user or a service person from operating it by mistake.

  Furthermore, a switch that can be switched to an open state when the load 20 is turned on can also be used as the disconnect switch 7. As shown in FIG. 3, the disconnect switch 7 includes a detection circuit 31 for detecting power-on and a switch circuit 32 that is switched on and off by the detection circuit 31. The separation switch 7 is switched from on to off when the detection circuit 31 detects that the power is turned on. This disconnect switch 7 is automatically switched off when the metal case 4 is set in the vehicle on the load 20 side and the power is turned on in the use state. Therefore, until the metal case 4 is set on the load 20 side and used, the electrostatic absorption capacitor 6 prevents harmful effects caused by static electricity. When the metal case 4 is in use, the electrostatic absorption capacitor 6 is disconnected and the voltage detection circuit 3 The voltage of the battery 2 can be accurately detected.

  Further, the disconnect switch 7 may be a switch that can be switched to an open state with the metal case 4 set on the load 20 side. As shown in FIG. 4, the disconnecting switch 7 includes a plunger 33 in which the metal case 4 is set and pushed into the load 20 side. The separation switch 7 is in an open state when the plunger 33 is pushed in and is in a closed state when the plunger 33 is not pushed in. In the state where the metal case 4 is set in the vehicle on the load 20 side, the plunger 33 is pushed in by a fixing bracket 34 fixed to the vehicle. The disconnect switch 7 is also in a closed state until the metal case 4 is set on the vehicle to prevent adverse effects due to static electricity, and is opened when the metal case 4 is set in the vehicle. Detect the voltage at

  Furthermore, although not shown, the disconnection switch may be a lead wire that is disconnected after the metal case is set on the load side. For example, the separation switch is a lead wire for connecting an electrostatic absorption capacitor and a metal case, and the lead wire is cut after the metal case is set and separated into an open state. This disconnecting switch can surely be brought into an open state by cutting a lead wire, and can be reliably prevented from returning to a closed state after being cut. This disconnect switch is also in a closed state where the lead wire is connected until the metal case is set in the vehicle, preventing adverse effects due to static electricity, and when the metal case is set in the vehicle, the lead wire is disconnected and opened. Thus, the voltage detection circuit accurately detects the voltage.

It is a schematic block diagram of the conventional power supply device. It is a schematic block diagram of the power supply device concerning one Example of this invention. It is a schematic block diagram of the power supply device concerning the other Example of this invention. It is a schematic side view which shows another example of a changeover switch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... High voltage battery 2 ... Battery 3 ... Voltage detection circuit 4 ... Metal case 5 ... Ground line 6 ... Electrostatic absorption capacitor 7 ... Isolation switch 8 ... Input capacitor 9 ... Contactor 10 ... Connection point 11 ... Multiplexer 12 ... A / D converter DESCRIPTION OF SYMBOLS 13 ... Control circuit 14 ... Input resistance 20 ... Load 21 ... Chassis earth 22 ... Inverter 23 ... Driving motor 24 ... Generator 25 ... Capacitor 31 ... Detection circuit 32 ... Switch circuit 33 ... Plunger 34 ... Fixing bracket 81 ... High voltage battery 82 ... Battery 83 ... Voltage detection circuit 86 ... Static absorption capacitor 90 ... Load 91 ... Chassis earth 95 ... Capacitor

Claims (6)

A high voltage battery (1) in which a plurality of rechargeable batteries (2) are connected in series, a voltage detection circuit (3) for detecting the voltage of the high voltage battery (1), and the high voltage battery (1) A metal case (4) that contains a load (20) to which power is supplied from, a high-voltage battery (1), a voltage detection circuit (3), and is connected to the chassis ground (21) of the load (20) ) And an electrostatic absorption capacitor (6) connected between the metal case (4) and the ground line (5) of the voltage detection circuit (3),
A separation switch (7) connected in series with the electrostatic absorption capacitor (6) is provided.When the separation switch (7) is closed, the electrostatic absorption capacitor (6) absorbs static electricity and the separation switch (7) A power supply device in which the voltage detection circuit (3) detects the voltage of the high-voltage battery (1) in the open state.   The power supply device according to claim 1, wherein the disconnect switch (7) is a switch that is mechanically switched between an open state and an open state.   The power supply device according to claim 1, wherein the disconnect switch (7) is a switch that is switched to an open state when the load (20) is turned on.   The power supply device according to claim 1, wherein the disconnect switch (7) is a switch that is set on the load (20) side and is switched to an open state.   The power supply device according to claim 1, wherein the disconnect switch (7) is a switch that cannot be operated from the outside while being set to the load (20).   The load (20) connected to the high-voltage battery (1) is an inverter (22) connecting a vehicle travel motor (23) and a generator (24) to the secondary side. The power supply described.

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