JP2015154618A - battery unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery unit that can suppress a disadvantage caused by formation of a passage parallel to a main connection passage by a load current passage.SOLUTION: A battery unit U having a Li storage battery 30 in which a lead storage battery 20 is connected to a first terminal P1, a rotary machine 10 is connected to a second terminal P2 and an electrical load 43 is connected to a third terminal P3, has main connection passages L1, L2 which connect the terminals P1, P2 and connect the Li storage battery 30 to a battery connection point N1, auxiliary connection passages L3, L4 for connecting the terminals P1, P2 in parallel to the passages L1, L2 and connecting an electrical load 43 to a load connection point N4, switches 51, 52 provided to the passages L1, L2, a switch 53 and a switch 54 which are provided to the passages L3, L4, and a switch 56 provided to a bypass passage B2 for connecting connection points N1, N4. A controller 60 controls switches 53, 54, 56 to inhibit current from flowing to the passages L3, L4, B2 through the load connection point N4.

Description

  The present invention relates to a technique in which an external storage battery and a rotating machine having a power generation function can be connected to a battery unit having an internal storage battery.

  For example, a configuration in which a plurality of storage batteries (for example, a lead storage battery and a lithium ion storage battery) are used as an in-vehicle power supply system mounted on a vehicle and power is supplied to various in-vehicle electric loads while using each of these storage batteries properly is known. (For example, refer to Patent Document 1).

  Specifically, a generator, a lithium ion storage battery, and a lead storage battery are connected by a main connection path, and two semiconductor switches are provided on the main connection path. The first semiconductor switch is provided between the generator and the lithium ion storage battery and the lead storage battery, and the second semiconductor switch is a battery connection point to which the first semiconductor switch, the generator, and the lithium ion storage battery are connected. And a lithium ion storage battery. At the time of regenerative power generation, by changing the open / close state of the two semiconductor switches, charging can be suitably performed according to the charge rates of the lead storage battery and the lithium ion storage battery.

JP 2012-80706 A

  In the power supply system using the two storage batteries, one storage battery and each semiconductor switch are built in the unit. And it is set as the structure which connects the other storage battery (external storage battery) and a generator (rotary machine) with respect to two terminals of the unit (battery unit) which has the built-in storage battery (internal storage battery), respectively. Here, the structure which connects an electric load to the position which can supply electric power from either one of an external storage battery and an internal storage battery can be considered.

  Specifically, the terminal connected to the external storage battery and the internal storage battery are connected by a path (sub-connection path) different from the main connection path to the load connection point on the sub-connection path. The electric load is connected. Thus, when the sub-connection path is provided, it is possible to supply power to the electric load from each of the internal storage battery and the external storage battery. On the other hand, as a result of forming a path in parallel with the main connection path, it is conceivable that the internal storage battery and the external storage battery are unintentionally brought into conduction, and a current flowing through the main connection path flows through the sub connection path.

  The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide means for suppressing inconvenience due to the formation of a path parallel to the main connection path by the load current path. .

  The present invention includes an internal storage battery (30), an external storage battery (20) is connected to the first terminal (P1), a rotating machine (10) having a power generation function is connected to the second terminal (P2), and a third A battery unit (U) in which an electric load (43) is connected to a terminal (P3), wherein the battery is connected between the first terminal and the second terminal and between the two terminals. The main connection path (L1, L2) for connecting the internal storage battery to the connection point (N1), the first terminal and the internal storage battery are connected in parallel with the main connection path, and the first terminal and the internal storage A sub-connection path (L3, L4) for connecting the electrical load to a load connection point (N4) between the storage batteries, and a first switch (between the first terminal and the battery connection point in the main connection path) 51), the battery connection point and the inside A main connection path opening / closing means having a second switch (52) provided between the storage batteries, between the first terminal and the load connection point in the sub connection path, the internal storage battery and the load connection. A third switch (53) and a fourth switch (54) respectively provided between the points; or between the third switch, the fourth switch, the battery connection point and the load connection point. A load current path opening / closing means having a bypass switch (56) provided in the bypass path (B2) for connecting the load current path opening / closing means, the path between the first terminal and the battery connection point, At least one of the path between the first terminal and the internal storage battery and the path between the battery connection point and the internal storage battery passes through the load connection point on the sub-connection path. Characterized in that it comprises a prohibition means (60, 80) for inhibiting a current from flowing into the respective path with.

  In the present invention, an electrical load is connected to a load connection point on the sub-connection path, a third switch is provided between the first terminal and the load connection point, and a fourth switch is provided between the internal storage battery and the load connection point. And With such a configuration, it is possible to supply power to the electric load by selectively using one of the external storage battery and the internal storage battery. Further, when the battery connection point and the load connection point are connected by a bypass route, and the bypass switch is provided on the bypass route, the electric load is passed through the bypass route without passing through the third switch and the fourth switch. It becomes the structure which can supply the electric power to. According to this, it is possible to supply power from the external storage battery to the electric load even when fail-safe or when the operation of the third and fourth switches is stopped.

Here, when the sub-connection path and the bypass path as the load current path are provided as described above, as a path parallel to the main connection path,
A path between the first terminal, the load connection point, and the battery connection point (for example, a path between the first terminal P1, the load connection point N4, and the battery connection point N1 in FIG. 1).
A path between the first terminal, the load connection point, and the internal storage battery (for example, a path between the first terminal P1, the load connection point N4, and the lithium ion storage battery 30 in FIG. 1).
-Path between battery connection point-load connection point-internal storage battery (for example, path between battery connection point N1-load connection point N4-lithium ion storage battery 30 in FIG. 1)
Are formed respectively. As current flows through each path that passes through these load connection points, an excessive current (generated current) flows from the rotating machine to the 3rd, 4th switch and bypass switch unintentionally, or between the batteries unintentionally conducted It becomes a state.

  In this respect, the load path opening / closing means is controlled, and at least one of the path between the first terminal and the battery connection point, the path between the first terminal and the internal storage battery, and the path between the battery connection point and the internal storage battery, It was set as the structure which prohibits that an electric current flows into each of these path | routes via the upper load connection point. For this reason, it is possible to suppress a generation current similar to that in the main connection path from flowing in the load current path or a current from flowing between the batteries through the load current path. As a result, in a battery unit applied to a battery system including two batteries, an unintended current in the load current path while appropriately charging each battery and supplying power to an electric load using each battery. The inconvenience due to the flowing of can be solved.

The electric circuit diagram which shows the power supply system of this embodiment. The figure which shows the state of each switch in a 1st state. The figure which shows the state of each switch in a 2nd state. The figure which shows the state of each switch in a 3rd state. The figure which shows the state of each switch in a 4th state. The figure which shows the state of each switch in a 5th state. The figure which shows the logic circuit which prohibits that an S-MOS switch and an S-SMR switch will be in an ON state. The flowchart which shows the ON operation prohibition / permission process of a 2nd bypass switch.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The battery unit of this embodiment is applied to an in-vehicle power supply system mounted on a vehicle, and the vehicle travels using an engine (internal combustion engine) as a drive source. The vehicle has a so-called idling stop function.

  As shown in FIG. 1, this power supply system includes a rotating machine 10, a lead storage battery 20, a lithium ion storage battery 30, a starter 41, various electric loads 42 and 43, a P-MOS switch 51 as a first switch, and a second switch. P-SMR switch 52 as a third switch, S-MOS switch 53 as a third switch, and S-SMR switch 54 as a fourth switch.

  Among these, the lithium ion storage battery 30 and each of the switches 51 to 56 are integrated by being accommodated in a housing (accommodating case) and configured as a battery unit U. Moreover, the battery unit U has the control part 60 which comprises a battery control means, and each switch 51-56 and the control part 60 are accommodated in the housing | casing in the state mounted in the same board | substrate.

  The battery unit U is provided with a first terminal P1, a second terminal P2, and a third terminal P3 as external terminals. The lead storage battery 20, the starter 41, and the electric load 42 are connected to the first terminal P1, The rotating machine 10 is connected to the two terminals P2, and the electric load 43 is connected to the third terminal P3. In this case, the lead storage battery 20 or the like is connected to the first terminal P1 via the harness H1, the rotating machine 10 is connected to the second terminal P2 via the harness H2, and the third terminal P3 via the harness H3. The electric load 43 is connected. Both the first terminal P1 and the second terminal P2 are large-current input / output terminals through which input / output currents of the rotating machine 10 flow.

  The rotating shaft of the rotating machine 10 is drivingly connected to a crankshaft of an engine (not shown) by a belt or the like. The rotating shaft of the rotating machine 10 is rotated by the rotation of the crankshaft, and the rotating shaft of the rotating machine 10 is rotated. Causes the crankshaft to rotate. In this case, the rotating machine 10 includes an electric power generation function for generating electric power (regenerative electric power generation) by rotating the crankshaft and a power output function for applying a rotational force to the crankshaft, and constitutes an ISG (Integrated Starter Generator). It has become. As for the power output of the rotating machine 10, the engine is restarted by the rotating machine 10 when the engine is restarted by the idling stop control. In addition, output assistance (assist) by the rotating machine 10 is possible during vehicle travel.

  The lead storage battery 20 and the lithium ion storage battery 30 are electrically connected in parallel to the rotating machine 10, and the storage batteries 20, 30 can be charged by the generated power of the rotating machine 10. The rotating machine 10 is driven by power feeding from the storage batteries 20 and 30.

  The lead storage battery 20 is a well-known general-purpose storage battery. On the other hand, the lithium ion storage battery 30 is a high-density storage battery with less power loss during charging / discharging and higher output density and energy density than the lead storage battery 20. The lithium ion storage battery 30 is composed of an assembled battery formed by connecting a plurality of battery cells in series. The lead storage battery 20 corresponds to an “external storage battery”, and the lithium ion storage battery 30 corresponds to an “internal storage battery”.

In the battery unit U, a plurality of connection paths L <b> 1 to L <b> 4 for connecting the terminals P <b> 1 to P <b> 3 and the lithium ion storage battery 30 to each other are provided as in-unit electrical paths. this house,
The first connection path L1 is an electrical path that connects the first terminal P1 and the second terminal P2,
The second connection path L2 is an electrical path that connects the connection point N1 (battery connection point) on the first connection path L1 and the lithium ion storage battery 30;
The third connection path L3 is an electrical path that connects the connection point N2 on the first connection path L1 and the third terminal P3,
The fourth connection path L4 is an electrical path that connects the connection point N3 of the second connection path L2 and the connection point N4 (load connection point) of the third connection path L3.
Among these, the first connection path L1 and the second connection path L2 correspond to “main connection paths”, and the third connection path L3 and the fourth connection path L4 correspond to “sub connection paths”.

And
A P-MOS switch 51 is provided in the first connection path L1 (specifically, between N1 and N2),
A P-SMR switch 52 is provided in the second connection path L2 (specifically, between N1 and N3),
An S-MOS switch 53 is provided in the third connection path L3 (specifically, between N2 and N4),
An S-SMR switch 54 is provided in the fourth connection path L4 (specifically, between N3 and N4).
Each of these switches 51 to 54 includes 2 × n MOSFETs (semiconductor switches) and is connected in series so that the parasitic diodes of the pair of MOSFETs are opposite to each other. By this parasitic diode, when each switch 51 to 54 is turned off, the current flowing through the path in which the switch is provided is completely cut off. The first connection path L1 and the second connection path L2 are large current paths that are assumed to cause a relatively large current to flow between the rotating machine 10 and the storage batteries 20 and 30. Further, the third connection path L3 and the fourth connection path L4 are small current paths that are assumed to flow a smaller current than the connection paths L1 and L2. Therefore, the switches 51 and 52 provided in the connection paths L1 and L2 have larger allowable current amounts than the switches 53 and 54 provided in the connection paths L3 and L4. Specifically, as the switches 51 and 52, more MOSFETs are connected in parallel than the switches 53 and 54, thereby increasing the allowable current amount.

  Further, the battery unit U is provided with bypass paths B1 and B2 that allow the lead storage battery 20 to be connected to the rotating machine 10 and the electric load 43 without using the switches 51 and 53 in the unit. Specifically, the battery unit U of the present embodiment is provided with a fourth terminal P4, and the lead storage battery 20, the starter 41, and the electric load 42 are connected to the fourth terminal P4 via a fuse 44. ing. The fourth terminal P4 is connected to the connection point N1 on the first connection path L1 by the first bypass path B1 inside the battery unit U. A first bypass switch 55 is provided on the first bypass path B1 to turn off the connection between the fourth terminal P4 and the connection point N1.

  Further, in the battery unit U, a second bypass path B2 is provided so as to connect the connection point N1 on the first connection path L1 and the third terminal P3. A second bypass switch 56 is provided on the second bypass path B2 to turn off the connection between the connection point N1 and the third terminal P3.

  The first bypass switch 55 and the second bypass switch 56 are normally closed relay switches. The lead storage battery 20, the rotating machine 10, and the lithium ion storage battery 30 are connected by bypassing the P-MOS switch 51 by the first bypass path B1. Further, the first bypass path B1 and the second bypass path B2 are connected in series, thereby bypassing the S-MOS switch 53 and connecting the lead storage battery 20 and the electric load 43 to each other.

  The control unit 60 switches the switches 51 to 54 between on (closed) and off (open). For example, at the time of discharging each storage battery 20, 30, the switches 51 to 54 are basically controlled so as to cut off the connection between the lead storage battery 20 and the lithium ion storage battery 30, and current flows from the lead storage battery 20 to the lithium ion storage battery 30. It is suppressed that current flows from the lithium ion storage battery 30 to the lead storage battery 20. Thereby, the power loss accompanying a current flowing between both storage batteries can be suppressed.

  The control unit 60 is connected to an ECU 70 (electronic control device) outside the battery unit. That is, the control unit 60 and the ECU 70 are connected via a communication network such as CAN and can communicate with each other, and various data stored in the control unit 60 and the ECU 70 can be shared with each other. The ECU 70 performs idling stop control. As is well known, the idling stop control is to automatically stop the engine when a predetermined automatic stop condition is satisfied, and to restart the engine when the predetermined restart condition is satisfied under the automatic stop state.

  The electric load 43 is a constant voltage required electric load in which the voltage of the supplied power is substantially constant or the voltage fluctuation is required to be stable within a predetermined range. The lead load battery 20 is connected to the electrical load 43 via the S-MOS switch 53, and the lithium ion storage battery 30 is connected via the S-SMR switch 54. The lead storage battery 20 and the lithium ion storage battery 30 Power is supplied from either one. However, in the present embodiment, the lithium ion storage battery 30 mainly shares power supply to the electric load 43 that is a constant voltage required electric load.

  Specific examples of the electric load 43 include an in-vehicle navigation device and an in-vehicle audio device. For example, when the voltage of the supplied power is not constant and fluctuates greatly, or when it fluctuates greatly beyond the predetermined range, the voltage instantaneously drops below the minimum operating voltage, and the in-vehicle navigation There arises a problem that the operation of the device is reset. Therefore, the electric power supplied to the electric load 43 is required to be stable at a constant value where the voltage does not drop below the minimum operating voltage.

  The electric load 42 is a general electric load other than the electric load 43 (constant voltage required electric load) and the starter 41. Specific examples of the electric load 42 include wipers such as a headlight and a front windshield, a blower fan for an air conditioner, and a defroster heater for a rear windshield. The electric load 42 includes a driving load that shifts from a stopped state to a driven state when a predetermined driving condition is satisfied, and returns to the stopped state when the condition is not satisfied. The driving load is, for example, power steering or a power window. The starter 41 and the electrical load 42 are electrically connected to the lead storage battery 20 side with respect to the P-MOS switch 51, and the lead storage battery 20 mainly shares power supply to the starter 41 and the electrical load 42. .

  The rotating machine 10 generates power using the rotational energy of the crankshaft of the engine. The electric power generated by the rotating machine 10 is supplied to the electric loads 42 and 43 and also supplied to the lead storage battery 20 and the lithium ion storage battery 30. When the driving of the engine is stopped and power generation is not performed by the rotating machine 10, electric power is supplied from the lead storage battery 20 and the lithium ion storage battery 30 to the rotating machine 10, the starter 41, and the electric loads 42 and 43. The amount of discharge from each storage battery 20, 30 to the rotating machine 10, the starter 41 and the electric loads 42 to 43 and the amount of charge from the rotating machine 10 to each storage battery 20, 30 are determined by the SOC (State of of each storage battery 20, 30). charge: Control is performed so that the state of charge, that is, the ratio of the actual charge amount to the charge amount at the time of full charge, is in a range (appropriate range) where overcharge / discharge does not occur.

  Control unit 60 detects the temperature, output voltage, and charge / discharge current of lithium ion storage battery 30, and calculates the SOC of lithium ion storage battery 30 based on the detected values. Further, the control unit 60 detects the temperature, output voltage, and charge / discharge current of the lead storage battery 20, and calculates the SOC of the lead storage battery 20 based on the detected values. The control unit 60 turns off the switches 51 to 54 based on the SOC of each storage battery, and performs control so that the SOC falls within an appropriate range. In addition, each of the switches 51 to 54 is provided with a current sensor, and the control unit 60 acquires a detected value of the current flowing through each of the switches 51 to 54. Moreover, the voltage sensor is provided in the terminals P1-P3 of the battery unit U, and the control part 60 acquires the detected value of the voltage of the terminals P1-P3, respectively.

  In the present embodiment, the decelerating regeneration is performed in which the rotating machine 10 is generated by the regenerative energy of the vehicle and charged to both the storage batteries 20 and 30 (mainly the lithium ion storage battery 30). This deceleration regeneration is performed under the control of the ECU 70 when conditions such as that the vehicle is decelerating and that fuel injection to the engine is cut off are satisfied.

  Here, both the storage batteries 20 and 30 are connected in parallel to the rotating machine 10. For this reason, when the electric power generated by the rotating machine 10 is charged, the storage battery having the lower terminal voltage is preferentially charged. At the time of regenerative power generation, the lithium ion storage battery 30 is charged with priority over the lead storage battery 20 so that the terminal voltage of the lithium ion storage battery 30 is lower than the terminal voltage of the lead storage battery 20. ing. Such a setting can be realized by setting the open end voltage and the internal resistance value of both the storage batteries 20 and 30. The open end voltage can be set using the positive electrode active material, the negative electrode active material and the electrolyte of the lithium ion storage battery 30. It can be realized by selecting.

  In the present embodiment, the engine is automatically stopped by idling stop control, and then the engine is automatically restarted by driving the rotating machine 10. Further, after the restart, output assist (start assist) for applying torque to the crankshaft is performed by the rotating machine 10 until the speed of the vehicle reaches a predetermined speed. Further, when the vehicle is running and the accelerator pedal is depressed by the driver to accelerate the vehicle, the rotating machine 10 performs output assistance (intermediate assist) that applies torque to the crankshaft. The intermediate assist is performed even in a situation where a high output is required for the crankshaft, such as when traveling on a steep slope. Both the start assist and the intermediate assist are performed under the control of the ECU 70. By performing the start assist and the intermediate assist, the fuel efficiency of the vehicle can be improved.

  A current corresponding to the amount of torque that the rotating machine 10 applies to the crankshaft supplies electric power to the rotating machine 10 as the rotating machine 10 is driven at the time of starting, starting assist, and intermediate assist. Flows into the storage battery. The output voltage of the storage battery is lowered by this current and the internal resistance of the storage battery. Due to the decrease in the output voltage of the storage battery according to the torque applied by the rotating machine 10, the voltage of the electric power supplied to the constant voltage requesting electric load 43 may also temporarily decrease, and an unexpected operation reset may occur. is there.

  Therefore, in the present embodiment, the control unit 60 appropriately controls the state of each of the switches 51 to 54 according to the traveling state of the vehicle, so that the operation of the constant voltage requesting electric load 43 is reset while the vehicle is traveling. Suppress defects. Specifically, the switches 51 to 54 are in the following first state to fifth state.

  In the first state shown in FIG. 2, the switches 51, 52, and 54 are turned on, and only the S-MOS switch 53 is turned off. In this first state, the lead storage battery 20 and the lithium ion storage battery 30 are in a conductive state, and both the storage batteries 20, 30 and the rotating machine 10 and the electrical load 43 are in a conductive state. At the time of regenerative power generation, the switch state is set to the first state in order to charge both storage batteries 20 and 30. In addition, the switch state is set to the first state also at the start assist after the idling stop restart.

  In the second state shown in FIG. 3, the switches 51 and 54 are turned on, and the switches 52 and 53 are turned off. In this second state, the lead storage battery 20 and the rotating machine 10 are in a conductive state, and the electrical load 43 and the lithium ion storage battery 30 are in a conductive state. Moreover, the lead storage battery 20 and the lithium ion storage battery 30 are cut off. A switch for the purpose of stabilizing the voltage of the electric power supplied to the electric load 43 at the time of running without assistance by the rotating machine 10 (during normal running), when the engine is stopped at idling stop, and when the engine is restarted at idling stop. Let the state be the second state.

  In the third state shown in FIG. 4, the switches 52 and 54 are turned on and the switches 51 and 53 are turned off. In the third state, the rotating machine 10 and the electric load 43 and the lithium ion storage battery 30 are in a conductive state. Moreover, the lead storage battery 20 and the lithium ion storage battery 30 are cut off. The purpose is to supply electric power from the lithium ion storage battery 30 to the rotating machine 10 to reduce the remaining capacity (charge rate) of the lithium ion storage battery 30 and to charge the lithium ion storage battery 30 with more power generated during regenerative power generation. As a result, at the time of intermediate assist, the switch state is basically set to the third state.

  In the fourth state shown in FIG. 5, the switches 51 and 53 are turned on, and the switches 52 and 54 are turned off. In the fourth state, the rotating machine 10, the electrical load 43, and the lead storage battery 20 are in a conductive state. Moreover, the lead storage battery 20 and the lithium ion storage battery 30 are cut off. In order to prevent overdischarge of the lithium ion storage battery 30, the switch state is set to the fourth state immediately after the IG is turned on and during cold start and when the remaining capacity of the lithium ion storage battery 30 is reduced.

  In the fifth state shown in FIG. 6, the switches 52 and 53 are turned on, and the switches 51 and 54 are turned off. In the fifth state, the rotating machine 10 and the lithium ion storage battery 30 are in a conductive state, and the electrical load 43 and the lead storage battery 20 are in a conductive state. Moreover, the lead storage battery 20 and the lithium ion storage battery 30 are cut off. At the time of the intermediate assist, when the current flowing through the rotating machine 10 is a predetermined amount or more and the output voltage of the lithium ion storage battery 30 is greatly reduced, the switch state is set to the fifth state.

  As described above, in the first state, the lead storage battery 20 and the lithium ion storage battery 30 are in a conducting state, and the lead storage battery 20, the lithium ion storage battery 30, the rotating machine 10, and the electric load 43 are in a conducting state. Moreover, in the 2nd-5th state, the lead storage battery 20 and the lithium ion storage battery 30 are made into the interruption | blocking state, and each of the rotary machine 10 and the electrical load 43 is electrically connected with either one of the lead storage battery 20 and the lithium ion storage battery 30. State.

  Here, if an open abnormality (always off abnormality) occurs in the P-MOS switch 51 while the in-vehicle power supply system is in the IG on state, power is supplied from the rotating machine 10 to the lead storage battery 20. I can't. In this case, as a result of the continued supply of electric power from the lead storage battery 20 to the electric load 42, the charge rate of the lead storage battery 20 decreases, and the electric load 42 eventually becomes a power failure. Therefore, the lead storage battery 20 and the rotating machine 10 are connected via the first bypass path B1. Thereby, when an open abnormality occurs in the P-MOS switch 51, the first bypass switch 55 is turned on, so that power can be supplied from the rotating machine 10 to the lead storage battery 20.

  As shown in FIGS. 2 to 6, one of the S-MOS switch 53 and the S-SMR switch 54 is turned on. Thereby, electric power is supplied from the lead storage battery 20 or the lithium ion storage battery 30 to the electric load 43. Here, when both the S-MOS switch 53 and the S-SMR switch 54 are turned off due to an open abnormality or the like while the in-vehicle power supply system is in the IG on state, the lead storage battery 20 and the lithium ion storage battery The electric load 43 cannot be supplied from each of the electric loads 43, and the electric load 43 becomes a power source failure. Therefore, the lead storage battery 20 and the electrical load 43 are connected via the first bypass path B1 and the second bypass path B2, and both the S-MOS switch 53 and the S-SMR switch 54 are subjected to an abnormality. The bypass switch 55, 56 is configured to perform an operation (ON operation) to turn on both. Thereby, it becomes possible to supply electric power from the lead storage battery 20 to the electric load 43 without using both the switches 53 and 54, and the power supply failure in the electric load 43 can be suppressed.

  In addition, power supply (so-called dark current supply) to the electric loads 42 and 43 when the in-vehicle power supply system is in the IG off state is performed from the lead storage battery 20 in order to suppress the lithium ion storage battery 30 from being overdischarged. Is desirable. This is because lithium ion storage batteries have a greater degree of deterioration due to overdischarge than lead storage batteries. In addition, in order to suppress power consumption required for driving the MOS-FET (for example, power consumption due to gate leakage current), it is desirable that the switches 51 to 54 are turned off during dark current supply.

  Therefore, when the IG is turned off, power is supplied from the lead storage battery 20 to the electric load 43 via the first bypass path B1 and the second bypass path B2. That is, the control unit 60 turns on the bypass switches 55 and 56 on condition that the IG is off. Since the first bypass switch 55 and the second bypass switch 56 provided on the first bypass path B1 and the second bypass path B2 are normally closed relay switches, a current for driving the relay switch is not supplied. When stopped, it is turned on. That is, it is possible to suppress power consumption associated with keeping the switch in a conductive state when supplying dark current.

  Further, a fuse 44 is provided between the fourth terminal P4 of the battery unit U and the connection point N5 to which the first terminal P1 and the lead storage battery 20 are connected. If a ground fault occurs in the second terminal P2 or the harness H2 while the first bypass switch 55 is turned on, a large current flows from the lead storage battery 20 to the point where the ground fault occurs. In addition, if a ground fault occurs in the third terminal P3 or the harness H3 while the first bypass switch 55 and the second bypass switch 56 are in the on state, the ground fault from the lead storage battery 20 is large. Current flows. When such a large current flows, the fuse 44 is blown, so that it is possible to suppress a secondary failure associated with the continuous large current.

  Here, since the bypass paths B1 and B2 are connected in series, it is not necessary to provide the fuse 44 for each of the bypass paths B1 and B2, and the number of parts can be reduced. Since the fuse 44 is provided outside the battery unit U, the fuse 44 can be easily replaced when the fuse 44 is blown.

  Returning to the description of FIG. 1, the sub-connection paths L <b> 3 and L <b> 4 and the second bypass path B <b> 2 constitute a load current path for supplying power to the electric load 43. The load current paths L3, L4 and B2 are configured to connect the connection points N1 to N3 on the main connection paths L1 and L2.

  Specifically, a path is formed by the sub-connection paths L3 and L4 between the connection point N2 (first terminal P1) and the connection point N3 (lithium ion storage battery 30), and an S-MOS switch 53 and An S-SMR switch 54 is provided. In this case, when both the S-MOS switch 53 and the S-SMR switch 54 are turned on, the lead storage battery 20 and the lithium ion storage battery 30 regardless of whether the P-MOS switch 51 and the P-SMR switch 52 are on or off. Are made conductive. When the lead storage battery 20 and the lithium ion storage battery 30 are brought into conduction, inter-battery charging occurs between the storage batteries 20 and 30, resulting in power loss.

  Further, a path is formed by the sub-connection path L3 and the second bypass path B2 between the connection point N1 and the connection point N2 (first terminal P1), and the S-MOS switch 53 and the second bypass switch 56 are on the path. Is provided. In this case, when both the S-MOS switch 53 and the second bypass switch 56 are turned on, the first terminal P1 and the second terminal P2 are turned on regardless of whether the P-MOS switch 51 is on or off. The For this reason, although the P-MOS switch 51 is set in the OFF state, an unexpected current may flow between the connection point N1 and the first terminal P1.

  Further, a path is constituted by the sub-connection path L4 and the second bypass path B2 between the battery connection point N1 and the connection point N3 (lithium ion storage battery 30), and the S-SMR switch 54 and the second bypass switch 56 are provided on the path. Is provided. In this case, when both the S-SMR switch 54 and the second bypass switch 56 are turned on, the battery connection point N1 and the lithium ion storage battery 30 are turned on regardless of whether the P-SMR switch 52 is turned on or off. For this reason, although the P-SMR switch 52 is set in the OFF state, an unexpected current may flow between the battery connection point N1 and the lithium ion storage battery 30.

  Here, when the P-MOS switch 51 is turned on and charging current flows from the rotating machine 10 to the lead storage battery 20, or when driving current flows from the lead storage battery 20 to the rotating machine 10 A large current flows through the main connection path L1 via the P-MOS switch 51. When a large current is flowing through the P-MOS switch 51 and the S-MOS switch 53 and the second bypass switch 56 are both turned on, the S-MOS switch 53 provided in parallel with the P-MOS switch 51 and A large current flows through the second bypass switch 56. The allowable current amount of the S-MOS switch 53 provided in the sub-connection path L3 and the second bypass switch 56 provided in the second bypass path B2 is larger than the allowable current amount of the P-MOS switch 51. small. For this reason, when a large current flows through the S-MOS switch 53 and the second bypass switch 56, there is a concern that the S-MOS switch 53 and the second bypass switch 56 may be damaged.

  Further, when the P-SMR switch 52 is set to the on state and the charging current flows from the rotating machine 10 to the lithium ion storage battery 30, or the driving current flows from the lithium ion storage battery 30 to the rotating machine 10. In this case, a large current flows through the main connection path L2 via the P-SMR switch 52. When a large current flows through the P-SMR switch 52, when both the S-SMR switch 54 and the second bypass switch 56 are turned on, the S-SMR switch 54 provided in parallel with the P-SMR switch 52 and A large current flows through the second bypass switch 56. The allowable current amount of the S-SMR switch 54 provided in the sub-connection path L4 and the second bypass switch 56 provided in the second bypass path B2 is larger than the allowable current amount of the P-SMR switch 52. small. For this reason, when a large current flows through the S-SMR switch 54 and the second bypass switch 56, there is a concern that the S-SMR switch 54 and the second bypass switch 56 may be damaged.

  In view of the above circumstances, in this embodiment, the switches 53, 54, and 56 as load current path switching means are controlled, the path between the first terminal P1 and the connection point N1, the first terminal, and the lithium ion storage battery 30. And at least one of the path between the connection point N1 and the lithium ion storage battery 30 is prohibited from flowing a current to each of these paths via the load connection point N4 on the sub-connection paths L3 and L4. It was set as the structure to do. For this reason, a generated current similar to that of the main connection paths L1, L2 flows through the load current paths L3, L4, B2, or a current flows between the batteries 20, 30 via the load current paths L3, L4, B2. This can be suppressed. As a result, in the battery unit U applied to the battery system including the two batteries 20 and 30, charging of the batteries 20 and 30 and power supply to the electric load 43 using the batteries 20 and 30 are appropriately performed. While doing so, the inconvenience due to unintended current flowing in the load current paths L3, L4, B2 can be eliminated.

  Specifically, as shown in the first state to the fifth state, the control unit 60 performs control so that the S-MOS switch 53 and the S-SMR switch 54 are not turned on at the same time.

  Here, the S-MOS switch 53 and the S-SMR switch 54 are positive logics that are turned on when the voltage (gate voltage) applied to their respective gates is in a high state and turned off when the voltage is set to a low state. MOS-FET. A command signal for commanding off / on of the S-MOS switch 53 is a signal Ssm, and a command signal for commanding off / on of the S-SMR switch 54 is a signal Sss. The signals Ssm and Sss are respectively output from the switch command unit 61 of the control unit 60 to the switches 53 and 54 so that the switches 53 and 54 are in the states shown in the first state to the fifth state. Here, there is a concern that the signals Ssm and Sss are both in a high state and the switches 53 and 54 are both in an on state due to malfunction of the switch command unit 61 or noise mixing. In view of this, a logic circuit including a logic operation element is used to prohibit the switches 53 and 54 from being turned on at the same time.

  FIG. 7 shows a logic circuit 80 that prohibits the switches 53 and 54 from being turned on simultaneously. The logic circuit 80 is provided between the switch command unit 61 and the switches 53 and 54. The signals Ssm and Sss output from the switch command unit 61 are input to the AND circuit 81 of the logic circuit 80, and the output of the AND circuit 81 is input to the NOT circuit 82. The output of the NOT circuit 82 and the signal Sss are input to the AND circuit 83. The signal Ssm is input to the gate of the S-MOS switch 53, and the output of the AND circuit 83 is input to the gate of the S-SMR switch 54. With such a configuration, when both the signals Ssm and Sss are in a high state, the signal Ssm is converted by the logic circuit 80 and the S-SMR switch 54 is forcibly turned off. In addition, when one of the signals Ssm and Sss is in a high state and the other is in a low state, and when both the signals Ssm and Sss are in a low state, the signals Ssm and Sss are converted by the logic circuit 80. Instead, it is input to the gates of the S-MOS switch 53 and the S-SMR switch 54.

  As described above, the logic circuit 80 prohibits both the S-MOS switch 53 and the S-SMR switch 54 from being turned on. As a result, the lead storage battery 20 and the lithium ion storage battery 30 are prevented from conducting unexpectedly through the sub-connection paths L3 and L4, and the inter-battery connection between the storage batteries 20 and 30 is performed. Can be prevented from occurring. When the above-described logic circuit 80 is used, when both the signals Ssm and Sss are set to the high state, the signal Ssm is converted to the high state and the signal Sss is converted to the low state. A logic circuit in which the signal Ssm is converted to a low state and the signal Sss is converted to a high state when both are set to a high state may be used.

  When both the S-MOS switch 53 and the S-SMR switch 54 are turned off, the connection between the load connection point N4 and the lead storage battery 20 and the lithium ion storage battery 30 is cut off, and the electric load 43 is connected to the power source. It will be a failure. Therefore, the control unit 60 prohibits the ON operation of the second bypass switch 56, and turns on the second bypass switch 56 when both the S-MOS switch 53 and the S-SMR switch 54 are turned off. It was configured to be allowed to. As a result, it is possible to supply power to the electric load 43 via the second bypass path B2 while suppressing an unexpected current from flowing through the load current paths L3, L4, and B2.

  Further, the second bypass path B2 connecting the battery connection point N1 to the load connection point N4 is provided in parallel to the main connection path L1. In this configuration, if the current flowing through the main connection path L1 is small, such as when the current flowing through the rotating machine 10 is small, even if the second bypass switch 56 is turned on, the S-MOS switch 53, the S-SMR switch 54, There is no inconvenience caused by an excessive current flowing through the second bypass switch 56. Therefore, the control unit 60 obtains a detection value Ipm of the current flowing through the P-MOS switch 51, that is, the current flowing through the connection path L1, and when the detection value Ipm is equal to or less than a predetermined value, the second bypass switch 56 is obtained. Is allowed to be turned on.

  Further, the second bypass path B2 that connects the battery connection point N1 to the load connection point N4 is provided in parallel to the main connection path L2. In this configuration, if the current flowing through the main connection path L2 is small, such as when the current flowing through the rotating machine 10 is small, the S-SMR switch 54 and the second bypass switch 56 can be turned on even if the second bypass switch 56 is turned on. There is no inconvenience caused by excessive current flow. Therefore, the control unit 60 acquires the detected value Ips of the current flowing through the P-SMR switch 52, that is, the current flowing through the connection path L2, and when the detected value Ips is equal to or smaller than the predetermined value, the second bypass switch 56 Is allowed to be turned on.

  As described above, by allowing the second bypass switch 56 to be turned on when the current flowing through the main connection paths L1 and L2 is small, it is possible to prevent an unexpected current from flowing through the load current paths L3, L4, and B2. However, it is possible to supply power to the electric load 43 via the second bypass path B2.

  In addition, the control unit 60 permits the second bypass switch 56 to be turned on when the P-SMR switch 52 is turned off. When all of the P-SMR switch 52, the second bypass switch 56, and the S-MOS switch 53 are turned on, the lithium ion storage battery 30 → P-SMR switch 52 → second bypass switch 56 → S-MOS switch 53 → A conduction path of the first terminal P1 occurs. For this reason, the lithium ion storage battery 30 and the lead storage battery 20 are made conductive, and inter-battery charging occurs. Therefore, the control unit 60 prohibits the second bypass switch 56 from being turned on, and permits the second bypass switch 56 to be turned on on condition that the P-SMR switch 52 is turned off. Made the configuration. Thereby, it becomes possible to supply electric power to the electric load 43 through the second bypass path B2 while suppressing the occurrence of a conduction path between the lithium ion storage battery 30 and the lead storage battery 20.

  In addition, the control unit 60 permits the second bypass switch 56 to be turned on when the P-SMR switch 52 is turned off. When all of the P-SMR switch 52, the second bypass switch 56, and the S-MOS switch 53 are turned on, the lithium ion storage battery 30 → P-SMR switch 52 → second bypass switch 56 → S-MOS switch 53 → A conduction path of the first terminal P1 occurs. For this reason, the lithium ion storage battery 30 and the lead storage battery 20 are made conductive, and inter-battery charging occurs. Therefore, a conduction path between the lithium ion storage battery 30 and the lead storage battery 20 is configured by permitting the second bypass switch 56 to be turned on on condition that the P-SMR switch 52 is turned off. Can be suppressed, and charging between batteries can be suppressed.

  Hereinafter, the on-operation prohibition / permission processing of the second bypass switch 56 will be described with reference to the flowchart shown in FIG. The on operation prohibition / permission process is performed by the control unit 60 at predetermined intervals.

  In step S11, it is determined whether or not both the S-MOS switch 53 and the S-SMR switch 54 are turned off. When both the S-MOS switch 53 and the S-SMR switch 54 are in the off state (S11: YES), in step S12, the on operation of the second bypass switch 56 is permitted and the process is terminated. When the ON operation of the second bypass switch 56 is permitted, for example, in a situation where an abnormality occurs in one of the S-MOS switch 53 and the S-SMR switch 54, or the power supply system is turned off. Under the circumstances, the second bypass switch 56 is turned on.

  When at least one of the S-MOS switch 53 and the S-SMR switch 54 is turned on (S11: NO), a detected value Ipm of the current flowing through the P-MOS switch 51 is acquired and detected in step S13. It is determined whether or not the value Ipm is less than or equal to a predetermined threshold value Ith1. When the detection value Ipm is greater than Ith1 (S13: NO), the on operation of the second bypass switch 56 is prohibited and the process is terminated.

  If the detection value Ipm is equal to or smaller than the predetermined threshold value Ith1 (S13: YES), it is determined in step S14 whether or not the P-SMR switch 52 is in an on state. When the P-SMR switch 52 is in the off state (S14: NO), in step S12, the on operation of the second bypass switch 56 is permitted and the process is terminated. If the P-SMR switch 52 is in the on state (S14: YES), it is determined in step S15 whether or not the detected value Ips of the current flowing through the P-SMR switch 52 is equal to or less than a predetermined threshold value Ith2. When the detected value Ips is equal to or smaller than the predetermined threshold value Ith2 (S15: YES), in step S12, the ON operation of the second bypass switch 56 is permitted and the process is terminated. On the other hand, if the detected value Ips is greater than the predetermined threshold value Ith2, in step S16, the ON operation of the second bypass switch 56 is prohibited and the process is terminated.

  Further, when a large current flows through the P-MOS switch 51, when the first bypass switch 55 (main bypass switch) is turned on, a first bypass path B1 (in parallel with the main connection path L1) ( A large current flows through the main bypass path). There is a concern that the fuse 44 may be blown by this large current. Therefore, the control unit 60 prohibits and permits the current to flow through the load connection point N4 in the load current paths L3, L4, and B2, acquires the detected value of the current flowing through the connection path L1, and detects the detected value. Is set to permit the first bypass switch 55 to be turned on when the value is equal to or less than a predetermined value. The control unit 60 acquires the detected value Ipm of the current flowing through the P-MOS switch 51 as the detected value of the current flowing through the connection path L1. Thereby, although the ground fault etc. have not arisen, the situation where the fuse 44 is blown can be suppressed.

(Other embodiments)
In the above embodiment, the command signals Ssm and Sss that command the on / off of the switches 53 and 54 are converted using the logic circuit 80, and the switches 53 and 54 are prohibited from being turned on simultaneously. However, instead of this, the control unit 60 determines whether one of the switches 53 and 54 is in an on state, and sets the other switch 53 and 54 in an on state based on the determination result. It is good also as a structure which prohibits this.

  Specifically, the control unit 60 includes off / on state acquisition means for acquiring the off / on states of the S-MOS switch 53 and the S-SMR switch 54. The off / on state acquisition means acquires, for example, detection values of currents flowing through the S-MOS switch 53 and the S-SMR switch 54, and turns off when the detection values are 0A and other than 0A. Judged as a state. When one of the S-MOS switch 53 and the S-SMR switch 54 is determined to be on based on the off / on state acquired by the off / on state acquisition means, the other switches 53 and 54 are turned on. It is set as the structure which prohibits it. As a result, the lead storage battery 20 and the lithium ion storage battery 30 are prevented from conducting unexpectedly through the sub-connection paths L3 and L4, and the inter-battery connection between the storage batteries 20 and 30 is performed. Can be prevented from occurring.

  A negative logic MOS-FET may be used as the S-MOS switch 53 and the S-SMR switch 54. Further, the S-MOS switch 53 and the S-SMR switch 54 may use IGBT switches or relay switches instead of the MOS-FETs.

  The second bypass switch 56 may be permitted to be turned on only when both the S-MOS switch 53 and the S-SMR switch 54 are turned off. Even with this configuration, it is possible to suppress a large current from flowing through the load current paths L3, L4, and B2 and the occurrence of inter-battery connection.

  A configuration that permits the on operation of the second bypass switch 56 when the current flowing through the main connection paths L1 and L2 is equal to or less than a predetermined threshold regardless of whether the S-MOS switch 53 and the S-SMR switch 54 are on or off. Also good. With this configuration, it is possible to suppress a large current from flowing through the load current paths L3, L4, and B2.

  The second bypass switch when the P-SMR switch 52 is in the off state regardless of the on / off state of the S-MOS switch 53 and the S-SMR switch 54 and the current flowing through the main connection paths L1 and L2. It is good also as a structure which permits 56 ON operation. In this structure, it can suppress that the connection between batteries via main connection path | route L2 and load current path | route L3, B2 arises.

  A battery other than the lithium ion battery may be used as the internal storage battery built in the battery unit U, and a battery other than the lead storage battery may be used as the external storage battery connected to the first terminal P1 of the battery unit U. For example, both the internal storage battery and the external storage battery may be lead storage batteries, or may be both lithium ion storage batteries.

  DESCRIPTION OF SYMBOLS 10 ... Rotating machine, 20 ... Lead storage battery, 30 ... Lithium ion storage battery, 43 ... Electric load, 51 ... P-MOS switch, 52 ... P-SMR switch, 53 ... S-MOS switch, 54 ... S-SMR switch, 56 ... 2nd bypass switch, 60 ... control part, 80 ... logic circuit, B2 ... 2nd bypass path, L1 ... 1st connection path, L2 ... 2nd connection path, L3 ... 3rd connection path, L4 ... 4th connection path N1 ... battery connection point, N4 ... load connection point, P1 ... first terminal, P2 ... second terminal, P3 ... third terminal, U ... battery unit.

Claims (6)

An internal storage battery (30) is provided, an external storage battery (20) is connected to the first terminal (P1), a rotating machine (10) having a power generation function is connected to the second terminal (P2), and a third terminal (P3) A battery unit (U) to which an electrical load (43) is connected,
A main connection path (L1, L2) for connecting the first storage terminal and the second terminal, and connecting the internal storage battery to a battery connection point (N1) between the two terminals;
A sub-connection path (L3) that connects the first terminal and the internal storage battery in parallel with the main connection path and connects the electrical load to a load connection point (N4) between the first terminal and the internal storage battery. , L4)
A first switch (51) provided between the first terminal and the battery connection point in the main connection path; and a second switch (52) provided between the battery connection point and the internal storage battery. A main connection path opening / closing means comprising:
A third switch (53) and a fourth switch (54) provided between the first terminal and the load connection point, and between the internal storage battery and the load connection point, respectively, in the sub-connection path; Or a load current path switching means comprising the third switch, the fourth switch, and a bypass switch (56) provided in a bypass path (B2) connecting between the battery connection point and the load connection point. ,
Controlling the load current path switching means, the path between the first terminal and the battery connection point, the path between the first terminal and the internal storage battery, and between the battery connection point and the internal storage battery Prohibiting means (60, 80) for prohibiting a current from flowing through each of the paths via the load connection point on the sub-connection path for at least one of the paths;
A battery unit comprising: The load current path switching means includes the third switch and the fourth switch,
The prohibiting means prohibits a current from flowing between the first terminal and the internal storage battery via the load connection point by opening at least one of the third switch and the fourth switch. The battery unit according to claim 1. The load current path switching means has the third switch, the fourth switch, and the bypass switch,
The prohibiting means opens the bypass switch so that a current flows between the first terminal and the battery connection point via the load connection point, or via the load connection point. And prohibiting current from flowing between the battery connection point and the internal storage battery,
Detecting means for detecting a current flowing through the main connection path;
First permitting means for permitting the bypass switch to be closed when a current flowing through the main connection path is a predetermined value or less;
The battery unit according to claim 1, further comprising: The load current path switching means has the third switch, the fourth switch, and the bypass switch,
The prohibiting means opens the bypass switch so that a current flows between the first terminal and the battery connection point via the load connection point, or via the load connection point. And prohibiting current from flowing between the battery connection point and the internal storage battery,
4. The apparatus according to claim 1, further comprising a second permission unit that permits the bypass switch to be closed when the second switch is in an open state. 5. Battery unit. The load current path switching means has the third switch, the fourth switch, and the bypass switch,
The prohibiting means opens the bypass switch so that a current flows between the first terminal and the battery connection point via the load connection point, or via the load connection point. And prohibiting current from flowing between the battery connection point and the internal storage battery,
5. The apparatus according to claim 1, further comprising third permission means for permitting the bypass switch to be in a closed state when both the third switch and the fourth switch are in an open state. The battery unit according to claim 1. A main bypass path (B1) that is provided in parallel with the main connection path and connects between the external storage battery and the battery connection point so as to bypass the first switch;
A main bypass switch (55) provided in the main bypass path;
Detecting means for detecting a current flowing through the main connection path;
A battery unit comprising:
6. The apparatus according to claim 1, further comprising a fourth permission unit that permits the main bypass switch to be closed when a current flowing through the main connection path is equal to or less than a predetermined value. The battery unit according to item.

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