Battery unit and power system

Abstract

Battery unit (U) adapted for a power system comprising a first battery (11) and a second battery (12) connected in parallel to an electrical load (15, 16), wherein the battery unit (U) comprises the second battery (12) connected to the first battery (11) and the electrical load (15, 16), wherein the battery unit (U) comprises: a first power connection (T0, T1) which is connected to the first battery (11) without a start switch (Sa1, Sa2) of the power system being arranged in between; a second power connection (T4, T5) which is connected to the first battery (11), with the start switch (Sa1, Sa2) located in between; a first line path (L1 - L4) which is connected to the first power terminal (T0, T1) or the second battery (12) which is used to supply power to the electrical load (15, 16); a first opening / closing unit (31 - 34) provided on the first conductor path (L1 - L4) which enables charging / discharging of the first and second batteries (11, 12) in response to an opening / closing actuation of the first opening / closing unit (31 - 34); a drive unit (52) that opens or closes the first opening / closing unit (31 - 34); a second conductor path (L11) that connects the first power connection (T0, T1) and the drive unit (52); and a second opening / closing unit (61) provided on the second line path (L11), wherein the second opening / closing unit (61) is closed when at least the start switch (Sa1, Sa2) is ON, wherein the second power connection (T4, T5) and the drive unit (52) are electrically connected by a connection path (L12, L13), and the second line path (L11) is configured from three power supply paths (L11a, L11b, L11c) which are intended to supply power to the drive unit (52).

Description

BACKGROUND OF THE INVENTION Technical field

[0001] The present disclosure relates to a battery unit and a power system. Description of the state of the art

[0002] A power system mounted on a vehicle uses a plurality of secondary batteries. For example, JP 2012-130 108 A, which corresponds to DE 10 2011 056 270 A1, discloses that a plurality of secondary batteries (for example, a lead-acid battery or a lithium-ion battery) are used to supply power to various electrical loads mounted on the vehicle. In particular, an electrical path is provided in which the lead-acid battery and the lithium-ion battery are connected in parallel with respect to the electrical loads, and semiconductor switches are arranged in the electrical path such that respective semiconductor switches are opened or closed by a switch drive unit to charge or discharge the electrical loads.

[0003] The switch drive unit is powered via a power supply path connected between the secondary battery and the switch drive unit. This supply path includes a dark-current cutoff switch that opens and closes in response to the ON / OFF operation of the power system's start switch. According to this configuration, when the power system's activation switch is ON, the dark-current cutoff switch closes (ON), supplying power to the switch drive unit. Conversely, when the start switch is OFF, the dark-current cutoff switch opens (OFF), stopping the power supply to the switch drive unit.According to the configuration described above, a dark current cut-off switch is provided in such a way that the current flowing to the switch drive unit is switched off, thereby achieving an efficient dark current in the power source system.

[0004] In the configuration described above, for example, the dark-current cutoff switch may be stuck in the open position (opening fault) for any reason, while the power system's start switch is ON. In this case, no power can be supplied to the switch drive unit from the secondary batteries. As a result, the semiconductor switches in the power source system cannot be switched between ON and OFF. Thus, the charging / discharging processes of various batteries can be affected by the phenomenon described above.

[0005] JP 2003-007347A discloses a power supply system in which electronic control units are supplied with voltage from a battery via first wires when a relay is closed. In the event of a fault in this circuit, the electronic control units can be supplied with voltage via another circuit running from the start switch via second wires.

[0006] JP 2001-236 871 A discloses an anomaly detection device for a switching element in a load drive device in which a starter relay is switched on via individual ISS starter relays or via an STA connection. A relay output of a drive circuit and the level (high or low level) of a contact voltage VJ and an STA voltage with respect to the position of an ignition switch at the individual ISS starter relays when they are operating normally are known in advance. By determining whether the voltage between the contacts VJ and the voltage VR of the STA are at a normal level, it is possible to detect which anomaly (switching-on or switching-off error) is caused at which of the individual ISS starter relays. SUMMARY

[0007] The present disclosure relates to the task of providing a battery unit capable of charging / discharging any battery in a power system, even if an opening fault occurs in the switch used therein, and an associated power system.

[0008] This problem is solved by a battery unit as specified in claim 1 and by a power system as specified in claim 5.

[0009] Advantageous embodiments are specified in the dependent patent claims.

[0010] A first embodiment of the present disclosure is a battery unit (U) as defined in claim 1. The battery unit is adapted for a power system comprising a first battery (11) and a second battery (12) connected in parallel to an electrical load (15, 16), wherein the battery unit includes the second battery (12) connected to the first battery and the electrical load.

[0011] According to the power system described above, when the start switch is ON, the second opening / closing unit closes, and the first opening / closing unit opens or closes. In this case, when the first opening / closing unit is closed, each battery can be charged or discharged. Conversely, when the start switch is OFF, the second opening / closing unit opens, and the drive unit prevents any ON / OFF operation of the first opening / closing unit. Assuming that the second opening / closing unit remains open even after the start switch is ON—i.e., an opening fault occurs in the second opening / closing unit—the first opening / closing unit cannot be opened or closed, and therefore, the desired charging or discharging of each battery cannot be achieved.

[0012] In this respect, according to the configuration described above, the second power terminal and the drive unit are electrically connected via the connection path, allowing the drive unit to be powered by the first battery so that it can open or close the first opening / closing unit. In other words, since the second power terminal is connected to the first battery via the start switch, voltage from the first battery is applied to the second power terminal. Therefore, this applied voltage can be used to supply power to the drive unit. Thus, even if the second opening / closing unit has an opening fault, the first opening / closing unit can still be opened or closed, and the respective batteries in the power system can be charged / discharged.

[0013] According to a second embodiment of the present disclosure specified in claim 2, the battery unit has a control unit (51) which performs an opening / closing actuation of the first opening / closing unit, wherein the control unit has an activation terminal (ST) to which the second power terminal is connected via a start signal line (SL1, SL2); wherein the control unit is configured to be activated when a voltage at the activation terminal assumes a high level; and the second power terminal and the drive unit are electrically connected by the connection path which is configured from a branch line branching off from the start signal line.

[0014] The start signal line, connected to the second power terminal, is designed to transmit a voltage signal to the control unit and is generally a high-impedance line. In this case, by connecting the second power terminal and the drive unit via the start signal line, even if they are always connected, when the start switch is ON, the drive unit's power is preferably supplied from the first battery through the second line path, including the second opening / closing unit, instead of through the connection path (start signal line). Accordingly, an existing system can preferably be used without placing an excessive load on the start signal line.

[0015] According to a third embodiment of the present disclosure specified in claim 3, the power system is adapted for a vehicle which is provided with a first start switch (Sa1) which allows the vehicle to be in a first operating state and a second start switch (Sa2) which allows the vehicle to be in a second operating state than the start switch; wherein the second power connection has a first input connection (T4) which is connected to the first battery via the first start switch and a second input connection (T5) which is connected to the first battery via the second start switch, wherein each of the first and second connections is connected to the activation connection via the start signal line;and each of the first and second input terminals and the drive unit are electrically connected to the connection path configured from a branch line branching off from the start signal line.

[0016] In the event of an opening fault at the second opening / closing unit while the start switch is ON, power is supplied to the drive unit via the start signal line. According to the configuration described above, the second power terminal is equipped with a first input terminal connected to the first start switch and a second input terminal connected to the second start switch. Each of these two input terminals and the drive unit are electrically connected via the start signal line. Thus, in the event of an opening fault at the second opening / closing unit while both the first and second start switches are ON, the current flowing through the connection path (start signal line) can be divided. This reduces the load on the start signal path.

[0017] According to a fourth embodiment of the present disclosure specified in claim 4, one end of the connection path is connected to a connection point (N15, N16) between the second opening / closing unit and the drive unit on the second line path; and the battery unit has a rectifier (D1, D2) on the connection path, wherein the rectifier limits a current flowing from the connection point to the second power terminal.

[0018] According to the configuration described above, one end of the connection path is connected to a connection point between the second opening / closing unit and the drive unit on the second connection path. In other words, the second power connection and the second connection path are connected, bypassing the second opening / closing unit. Thus, even if an opening fault occurs at the second opening / closing unit, power can still be supplied to the drive unit from the first battery. Furthermore, according to the configuration described above, a rectifier is provided on the connection path to restrict the direction of the current flow.Thus, for example, when the second opening / closing unit is closed, it can be prevented that a supply current flowing into the drive unit flows into the second power connection, thereby allowing power to be supplied to the drive unit in a suitable manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings show: Fig. 1 an electrical circuit diagram illustrating a power system according to the present embodiment, and Fig. 2. An explanatory diagram illustrating the opening / closing control of the switches. DETAILED DESCRIPTION OF PREFERRED EXECUTION EXAMPLES

[0020] The following are exemplary embodiments of the present disclosure with reference to the drawings. According to the exemplary embodiments, a vehicle-integrated power system is described that supplies power to various devices in the vehicle, which is powered by an internal combustion engine as a motive force.

[0021] As it is in Fig. As shown in Figure 1, the power source system 1 is configured as a dual power system, comprising a lead-acid battery 11 as a primary battery and a lithium-ion battery 12 as a secondary battery. An integrated starter-generator, which serves as both a generator and a motor, an ISG 16, is connected to the respective secondary batteries 11 and 12. The secondary batteries 11 and 12 are capable of supplying power to a starter 13 as well as to various electrical loads 14 and 15. In this system, the lead-acid battery 11 and the lithium-ion battery 12 are connected in parallel to the ISG 16 and are also connected in parallel to the electrical load 15.

[0022] The lead-acid battery 11 is a well-known universal secondary battery. In contrast, the lithium-ion battery 12 is configured as a high-density secondary battery, which, compared to the lead-acid battery 11, exhibits a high output power density, a high energy density, and low power loss during charging or discharging. The lithium-ion battery 12 may require a high energy efficiency during charging and discharging processes compared to the lead-acid battery 11. Furthermore, the lithium-ion battery 12 is configured as a battery pack in which several battery cells are connected. Both secondary batteries 11 and 12 have the same nominal voltage, for example, 12 V.

[0023] Although a detailed description with reference to the drawing is omitted, the lithium-ion battery 12 is housed in a casing configured as a battery unit U, which is integrated with a circuit board. The battery unit U is provided with output terminals T1, T2, T3, T0, where the lead-acid battery 11, the starter 13 and the electrical load 14 are connected to output terminals T1, T0, the ISG 16 is connected to output terminal T2, and the electrical load 15 is connected to output terminal T3.

[0024] Electrical loads 14 and 15 require different power voltages, supplied from their respective secondary batteries 11 and 12. Of these electrical loads, load 15 is a constant-voltage load, requiring a constant supply voltage or a stable supply voltage where the voltage only fluctuates within a predetermined range. In contrast, load 14 is a typical electrical load, distinct from a constant-voltage load. Load 15 is considered a protected load. Load 15 does not tolerate power failure. Load 14, however, can be considered a load that, unlike load 15, can tolerate power failure.

[0025] Specific examples of the electrical load 15, which is a constant voltage electrical load, include navigation devices, audio equipment, measuring instruments, and various ECUs (electronic control units), such as a power engine ECU. In this case, voltage fluctuations in the supply voltage are suppressed, thereby preventing unnecessary resets of the devices described above. As a result, stable operation can be ensured. The electrical load 15 may include driving system actuators such as an electric power steering unit and a braking unit. Furthermore, specific examples of the electrical load 14 include seat heating, a rear window defroster, headlights, a windshield wiper, and an air conditioning blower fan.

[0026] The rotating shaft of the ISG 16 is drivenly coupled to the (not shown) power machine output shaft via a belt or similar device, so that the rotating shaft of the ISG 16 is turned by the power machine output shaft. This means that the ISG 16 generates power (regenerative power generation) by rotating the power machine output shaft or axle. It should be noted that power is supplied from the respective secondary batteries 11 and 12 when the ISG 16 serves as the motor (motor operation), in which case the ISG 16 can be considered an electrical load.

[0027] Battery unit U has an ACC terminal T4 as an input terminal for the ACC signal and an IG terminal T5 as an input terminal for the IG signal. ACC terminal T4 is connected to the lead-acid battery 11 via an ACC switch Sa1, which acts as a start switch SW, and IG terminal T5 is connected to the lead-acid battery 11 via the IG switch Sa2, which acts as the start switch. The ACC switch Sa1 and the IG switch Sa2 are opened or closed by the driver. When these switches Sa1 and Sa2 are closed, battery unit U receives the ACC signal and the IG signal, respectively, generated by the power of the lead-acid battery 11. At this moment, voltage from the lead-acid battery 11 is applied to terminals T4 and T5. In this power system, the ACC switch Sa1 corresponds to the "first start switch," and the IG switch Sa2 corresponds to the "second start switch."

[0028] To connect the respective terminals T1, T0, T4, and T5 to the lead-acid battery 11, output terminals T0 and T1 are connected to the lead-acid battery 11 without the start switch SW1 being interposed. In contrast, ACC terminal T4 and IG terminal T5 are connected to the lead-acid battery 11 via the start switch SW1. According to the present embodiment, output terminal T0 corresponds to the "first power terminal," and ACC terminal T4 and IG terminal T5 correspond to the "second power terminal."

[0029] The start switch SW is switched between ON and OFF in response to a switch operation of a key component by the driver while the key component (IG key) is inserted. In this case, if only the ACC switch Sa1 is activated (closed) of the ACC switch Sa1 and the IG switch Sa2, the vehicle's state becomes an accessory operating state (first operating state). If both switches Sa1 and Sa2 are closed, the driving state becomes a ready-to-drive state (second operating state). Note that the state changes from the first operating state to the second operating state when the vehicle starts moving, and from the second operating state to the first operating state when the vehicle stops. In this embodiment, the ACC terminal T4 corresponds to a "first input terminal" and the IG terminal T5 corresponds to a "second input terminal".

[0030] The following describes an electrical configuration in battery unit U. As it is in Fig. As shown in Figure 1, the battery unit U has a conductor path L1 connecting the output terminals T1 and T2, and a conductor path L2 connecting a connection point N0 on conductor path L1 to the lithium-ion battery 12. A switch 31 is provided on conductor path L1 and a switch 32 is provided on conductor path L2. Switch 31 is located closer to the side of the lead-acid battery 11 than to connection point N0, and switch 32 is located closer to the side of the lithium-ion battery 12 than to connection point N0 in the conductor path between the lead-acid battery 11 and the lithium-ion battery 12.

[0031] These switches 31 and 32 are provided with n pairs of MOSFETs (metal-oxide-semiconductor field-effect transistors: semiconductor switching elements) such that the parasitic diodes of the MOSFET pairs are connected in series with opposite polarities. With these parasitic diodes, currents flowing under the condition that these switches are arranged are completely switched off when the respective switches 31 and 32 are OFF. Alternatively, IGBTs or bipolar transistors or the like can be used as switches 31 and 32 instead of the MOSFETs. In the case where IGBTs or bipolar transistors are used for switches 31 and 32, diodes can be connected in parallel with the respective switches 31 and 32 with opposite polarities instead of the parasitic diodes described above.

[0032] Furthermore, in connection path L1, one end of branch path L3 is connected to connection point N1, located between output terminal T1 and switch 31. In connection path L2, one end of branch path L4 is connected to connection point N2, located between lithium-ion battery 12 and switch 32. Other ends of branch paths L3 and L4 are connected to an intermediate point N3. Intermediate point N3 and output terminal T3 are connected to connection path L5. Connection paths L3 and L4 each contain a switch 33 and a switch 34, respectively. Each switch 33 and 34 is configured as a semiconductor switch, such as a MOSFET. Power can be supplied to an electrical load 15 from either battery 11 or 12 via respective paths L3–L5.

[0033] The battery unit U has bypass paths L0 and L6, which are provided to allow the lead-acid battery 11 to be connected to the electrical load 15 without the switches 31 to 34 being located in the unit between them. Specifically, in the battery unit U, bypass path L0 is configured such that output terminal T0 and connection point N0 are connected on connection path L1, and bypass path L6 is configured such that connection point N0 and output terminal T3 are connected. Furthermore, a bypass switch 41 is arranged on bypass path L0, and a bypass switch 42 is connected on bypass path L6. Each of the bypass switches 41 and 42 is, for example, a normally closed relay switch.

[0034] Closing bypass switch 41 electrically connects the lead-acid battery 11 and the electrical load 15, even if switch 31 is OFF (open). When both bypass switches 41 and 42 are closed, the lead-acid battery 11 and the electrical load 15 are electrically connected, even if switches 31 to 34 are all OFF (open). For example, if the start switch SW is OFF, dark current is supplied to the electrical load 15 via bypass switches 41 and 42. Note that the bypass path L0 and bypass switch 41 can be located outside the battery unit U.

[0035] The battery unit U is equipped with switches 31 to 34 and a control unit 50, which controls the ON / OFF (opening / closing) operation of the bypass switches 41 and 42. The control unit 50 comprises a microcomputer 51 including a CPU, ROM, RAM, and input / output interface, a charging pump IC 52, a battery monitoring IC 53, or the like. The microprocessor 51 controls the ON / OFF operation of switches 31 to 34 by means of a line command signal. The charging pump IC 52 outputs gate signals for the respective switches based on the line command signals of switches 31 to 34. Specifically, the charging pump IC 52 generates a boosted voltage corresponding to the gate voltage, thereby closing switches 31 to 34. According to the present embodiment, the microcomputer 51 corresponds to a “control unit” and the charging pump IC 52 corresponds to a “drive unit”.

[0036] The battery monitoring IC 53 detects the voltage of each of the multiple battery cells that make up the lithium-ion battery 12. In addition, the control unit 50 has a constant voltage circuit, which is not shown. The constant voltage circuit generates a constant voltage (for example, 5 V) that is used as a power supply voltage for the control unit 50 or the like.

[0037] The microprocessor 51 has an activation terminal ST that receives the start signals from the power system. The activation terminal ST is connected to the ACC terminal T4 via signal path SL1 and to the IG terminal T5 via signal path SL2, which branches off from signal path L1. According to this configuration, the microprocessor 51 receives the start signals (ACC signal, IG signal) via signal paths SL1 and SL2. These signals are transmitted to the battery unit U when the start switch SW is activated. At this time, the voltage applied to the activation terminal ST assumes a high level, thereby activating the microprocessor 51. It should be noted that signal paths SL1 and SL2 are configured with signal lines (start signal lines) that transmit the start signal.

[0038] The ECU 100, as an external unit of the battery unit U, is connected to the control unit 50. This means that the control unit 50 and the ECU 100 are connected via a communication network such as CAN (Control Area Network) to communicate with each other. This allows various data stored in the control unit 50 and the ECU 100 to be shared.

[0039] Control unit 50 controls the ON / OFF operation of switches 31 to 34 based on a command value transmitted from ECU 100, a higher-level control unit. This allows for the selective charging / discharging of either the lead-acid battery 11 or the lithium-ion battery 12. For example, control unit 50 calculates the state of charge (SOC) of the lithium-ion battery 12 and controls the charging and discharging rates to maintain the SOC within a predetermined range.

[0040] The power supply to the control unit 50 is described below. Batteries 11 and 12 supply power to the control unit 50.

[0041] The following describes a power supply path to the charging pump IC 52. As shown in Fig. As shown in Figure 1, the battery unit U has a power supply path L11 (L11a, L11b, L11c, L11d) that connects the charge pump IC 52 to the output terminals T0, T1, and T3. The power supply path L11 has a power supply path L11a branching from junction N11 between output terminal T0 and bypass switch 41 in bypass path L0, a power supply path L11b branching from junction N12 between output terminal T1 and switch 31 in connection path L1, and power supply paths L11c and L11d branching from junction N13 between switch 33 and output terminal T3 in connection path L3. One end of each of the connection paths L11a - L11c is connected to the connection point N14, and the connection point N14 and the charging pump IC 52 are connected through the power supply path L11d.In this way, the charging pump IC 52 is configured such that this power is supplied from three power supply paths.

[0042] A switch 61 is provided between connection point N14 and the charging pump IC on the power supply path L11d. Switch 61 is designed to cut off the current flowing to the charging pump IC 52 while the starter switch SW is OFF (engine stopped state). Switch 61 is configured as a semiconductor switch such as a MOSFET. Similar to the charging pump IC 52, power is supplied to the battery monitoring IC 53 via switch 61. In this embodiment, switches 31 to 34 correspond to a "first on / off unit," and switch 61 corresponds to a "second on / off unit."

[0043] Below is an ON / OFF control of switch 61 with reference to Fig. 2 described. It should be noted that Fig. Figure 2 shows a simplified wiring path of the control unit 50. Thus, the same reference symbols are used for similar configurations as described above. Fig. 1 applied, and for the sake of simplicity, its explanation is omitted.

[0044] Switch 61 is controlled on / off based on the ACC signal, the IG signal, and the drive command from ECU 100. Specifically, when ACC switch Sa1 is activated, the ACC signal is input to battery unit U to close (ON) switch 61. When IG switch Sa2 is activated, the IG signal is input to battery unit U to close (ON) switch 61. In other words, when start switch SW1 is activated, switch 61 is closed, so that power is supplied to the charging pump IC 52 via switch 61.

[0045] Conversely, when the start switch SW is switched off (the engine is stopped), the ACC signal and the IG signal are not input to the battery unit U, and the switch 61 is open (OFF). Thus, the current flowing from the lead-acid battery 11 to the charging pump IC 52 is switched off. Therefore, a dark current in the power system is effectively reduced.

[0046] According to the present power system, while the start switch SW is OFF, voltages between the battery cells that make up the lithium-ion battery 12 are balanced in a process that is carried out at a predetermined interval (e.g., 1 hour). Thus, at the time required to carry out the balancing process of the battery cells, the ECU 100 issues a battery monitoring command to the microprocessor 51. The microprocessor 51 transmits a drive command to the switch 61, thereby closing (ON) the switch 61. In this case, the switch 61 is closed, so that current is supplied to the battery monitoring IC 53. The battery monitoring IC 53 detects the voltages of the individual battery cells. The microprocessor 51 then carries out the balancing process when a predetermined voltage difference exists between a number of battery cells.

[0047] Depending on the power system configured in this way, an OFF fault (opening fault) can occur in switch 61. For example, if the start switch SW is ON (engine operating state), and switch 61 is fixed in the "open" position, no power can be supplied to the charging pump IC 52 via switch 61. As a result, the charging pump IC 52 cannot be used to perform ON / OFF control of switches 31 to 34.

[0048] According to the present embodiment, the ACC terminal 41, the IG terminal T5, and the charging pump IC 52 are electrically connected via a connection path. Specifically, a bypass supply path L12 is provided, branching off from the signal path SL1, which is connected to the ACC terminal T4, and connecting to the connection point N15 between the switch 61 and the charging pump IC 52 in the power supply path L11d. A bypass supply path L13 is also provided, branching off from the signal path L2, which is connected to the IG terminal T5, and connecting to the connection point N16 between the switch 61 and the charging pump IC 52 in the power supply path L11d. This means that a backup power supply path is provided without using the switch 61 to supply power to the charging pump IC 52, even if the switch 61 has an open fault.

[0049] It should be noted that a diode D1 is provided as a rectifier in the bypass supply path L12, and a diode D2 is provided as a rectifier in the bypass path L13. Diodes D1 and D2 are each arranged such that their anodes are connected to terminals T4 and T5, respectively, and their cathodes are connected to junctions N15 and N16. In other words, the diodes restrict current flow from junctions N15 and N16 to terminals T4 and T5. The rectifier is not limited to the use of diodes; thyristors can be used instead.

[0050] The ACC terminal T4 and the IG terminal T5 are designed as input terminals for transmitting a signal indicating that the power system's start switch SW is turned on to the battery unit U (microprocessor 51). In other words, the ACC terminal T4 and the IG terminal T5 are designed to accept signal sources. In this respect, according to the present embodiment, focusing on the voltage applied to terminals T4 and T5 corresponding to the voltage of the lead-acid battery 11 when the start switch SW is turned on, terminals T4 and T5 are used as voltage sources instead of signal sources.

[0051] As it is in Fig. As shown in Figure 1, the bypass supply paths L12 and L13 branch off from signal path SL1, which is connected to ACC terminal T4, and signal path SL2, which is connected to IG terminal T5, respectively. Alternatively, only one bypass supply path can be used, branching off from either signal path SL1 or signal path SL2. According to this configuration, power from the lead-acid battery can be supplied directly to the charge pump IC 52 without using switch 61.

[0052] In the power system described above, bypass power supply paths L12 and L13 are provided, ensuring that terminals T4 and T5 and the charging pump IC 52 are always connected. With this configuration, while the start switch SW is ON, power is supplied to the charging pump IC 52 primarily through switch 61. In this case, since signal paths SL1 and SL2 are intended for signal transmission, their impedances are relatively high compared to a connection path (e.g., power supply path L11) intended for power delivery. Therefore, while the start switch SW is on, power is supplied through a connection path with a low impedance, i.e., a line path through switch 61.

[0053] If, on the other hand, switch 61 has an opening fault, power is supplied to the charging pump IC 52 via the bypass supply paths L12 and L13. More precisely, in the first operating state, in which the ACC switch Sa1 is ON, power is supplied to the charging pump IC 52 only from the bypass supply path L12, and in the second operating state, in which the ACC switch Sa1 and the IG switch Sa2 are ON, power is supplied to the charging pump IC 52 via the connecting paths L12 and L13.

[0054] According to the present embodiment, the following advantageous effects can be achieved.

[0055] According to the power system described above, the charging pump IC 52 opens / closes switches 31 to 34. Therefore, assuming there are no bypass supply paths L12 and L13 and an opening fault occurs at switch 61, preventing power from being supplied to the charging pump IC 52, switches 31 to 34 cannot be controlled (opened or closed), and batteries 11 and 12 cannot be charged or discharged. For this reason, bypass supply paths L12 and L13 are provided to electrically connect the ACC terminal T4, the IG terminal T5, and the charging pump IC 52. In this case, even if switch 61 is open, power can be supplied to the charging pump IC 52 from the lead-acid battery 11. Thus, switches 31 to 34 can be opened or closed by the charging pump IC 52.In particular, since the ACC terminal T4 and the IG terminal T5 are connected to the lead-acid battery 11 via the start switch SW (Sa1, Sa2), voltage from the lead-acid battery is applied to terminals T4 and T5, allowing the voltage applied to T4 and T5 to be used as the power supply voltage for the charge pump IC 52. Thus, even if an opening fault occurs at switch 61, switches 31 to 34 can be controlled to open or close, enabling batteries 11 and 12 to be charged / discharged in the power system.

[0056] Signal paths SL1 and SL2, each connected to ACC terminal T4 and IG terminal T5 respectively, are designed to transmit a voltage signal to the control unit and are generally high-impedance lines. In this case, by connecting terminals T4 and T5 to the charging pump IC 52 via signal paths SL1 and SL2, even if these paths are always connected, power is supplied to the charging pump IC 52 from the lead-acid battery 11, preferably through supply path L11 with switch 61, instead of through the bypass supply paths L12 and L13 (signal paths SL1 and SL2). Accordingly, the existing system can preferably be used without subjecting signal paths SL1 and SL2 to an excessive load.

[0057] In the event of an opening fault while the start switch SW is ON, power is supplied to the charging pump IC 52 via signal paths SL1 and SL2. In the configuration described above, since the ACC terminal T4 is electrically connected to the ACC switch Sa1 and the IG terminal T5 to the IG switch Sa2, respectively, and thus to the charging pump IC 52 via signal paths SL1 and SL2, if an opening fault occurs at switch 61 while both the ACC switch Sa1 and the IG switch Sa2 are ON, the current flowing through the bypass supply paths L12 and L13 (signal paths SL1 and SL2) can be distributed. As a result, the load on signal paths SL1 and SL2 can be reduced.

[0058] Each end of the bypass supply paths L12 and L13 is connected to connection points N15 and N16, respectively, located between switch 61 and the charging pump IC 52 on supply path L11d. This means that, since ACC terminal T4 and IG terminal T5 are connected to supply path L11, bypassing switch 61, power can be supplied to the charging pump IC 52 from the lead-acid battery 11 even if switch 61 fails to open. Furthermore, in this configuration, diodes D1 and D2 are provided on bypass supply paths L12 and L13 to restrict the direction of current flow. Thus, when switch 61 is closed, it is possible to prevent a supply current flowing into the charging pump IC 52 from flowing into terminals T4 and T5, thereby allowing power to be supplied to the charging pump IC 52 in a suitable manner. (Another example)

[0059] According to the embodiment described above, the ambient supply paths L12 and L13 are configured to branch off from the signal paths SL1 and SL2. However, this configuration can be modified. For example, the bypass supply path L12 can be configured such that the ACC terminal T4 and the connection point N15 are connected without connecting the signal path SL1; that is, the ACC terminal T4 and the charge pump IC 52 are directly connected. Similarly, the bypass supply path L13 can be configured such that the IG terminal T5 and the connection point N16 are connected without connecting the signal path SL2. It should be noted that the diodes can be configured such that their anodes are connected to the respective terminals T4 and T5.

[0060] According to the embodiment described above, the supply path L11 is provided, in which the charging pump IC 52 is connected to the output terminals T0, T1, and T3. In particular, the supply path L11 is configured to include supply paths L11a, L11b, and L11c. However, this configuration can be modified. For example, the supply path L11 can be configured to connect the charging pump IC 52 to terminals T0 and T1. In other words, the supply path L11 includes L11a and L11b.

[0061] According to the configuration described above, battery unit U is equipped with terminal T0, and bypass path L0 is provided, with output terminal T0 and connection point N0 connected on connection path L1. However, output terminal T0 need not be provided, and bypass path L0 can branch off from connection path L1, which is connected to output terminal T1, to bypass switch 31. It should be noted that a dark current from the lead-acid battery 11 is supplied via output terminal T1 when the start switch SW is OFF.

[0062] According to Fig.1. Instead of using the configuration where the ISG 16 is connected to output terminal T2, a configuration where a generator is connected to output terminal T1 can be used. Furthermore, instead of using the configuration where the electrical load 15 (protected load) is connected to output terminal T3, a configuration where the electrical load 15 (protected load) is connected to output terminal T2 can be used.

[0063] According to the embodiments described above, a semiconductor switch such as a MOSFET is used as switch 61. However, a relay switch can be used instead of the semiconductor switch. Even in this configuration, switch 61 is controlled to open or close based on the ACC signal and the IG signal at ACC terminal T4 and IG terminal T5, respectively.

[0064] As described above, a battery unit U is provided which is adapted for a power system which is equipped with a first battery 11 and a second battery 12 which are connected in parallel to an electrical load 15, 16.The battery unit is equipped with the first battery and comprises: a first power terminal T0, T1 connected to the first battery; a second power terminal T4, T5 connected to the first battery, with the start switch located between them; a first opening / closing unit 31-34 provided on the first connection path, enabling charging / discharging of the first and second batteries in response to an opening / closing actuation of the first opening / closing unit; a drive unit 52 that opens or closes the first opening / closing unit; a second line path L11 connecting the first power terminal and the drive unit; and a second opening / closing unit 61 provided on the second connection path, the second opening / closing unit being closed when at least the start switch is ON.The second power connection and the drive unit are electrically connected via a connection path L12, L13.

Claims

[1] Battery unit (U) adapted for a power system comprising a first battery (11) and a second battery (12) connected in parallel to an electrical load (15, 16), wherein the battery unit (U) comprises the second battery (12) connected to the first battery (11) and the electrical load (15, 16), wherein the battery unit (U) comprises: a first power connection (T0, T1) which is connected to the first battery (11) without a start switch (Sa1, Sa2) of the power system being arranged in between; a second power connection (T4, T5) which is connected to the first battery (11), with the start switch (Sa1, Sa2) located in between; a first line path (L1 - L4) which is connected to the first power terminal (T0, T1) or the second battery (12) which is used to supply power to the electrical load (15, 16); a first opening / closing unit (31 - 34) provided on the first conductor path (L1 - L4) which enables charging / discharging of the first and second batteries (11, 12) in response to an opening / closing actuation of the first opening / closing unit (31 - 34); a drive unit (52) that opens or closes the first opening / closing unit (31 - 34); a second conductor path (L11) that connects the first power connection (T0, T1) and the drive unit (52); and a second opening / closing unit (61) provided on the second line path (L11), wherein the second opening / closing unit (61) is closed when at least the start switch (Sa1, Sa2) is ON, wherein the second power connection (T4, T5) and the drive unit (52) are electrically connected by a connection path (L12, L13), and the second line path (L11) is configured from three power supply paths (L11a, L11b, L11c) which are intended to supply power to the drive unit (52). [2] Battery unit (U) according to claim 1, wherein the battery unit (U) has a control unit (51) which performs an opening / closing operation of the first opening / closing unit (31 - 34), wherein the control unit (51) has an activation terminal (ST) to which the second power terminal (T4, T5) is connected via a start signal line (SL1, SL2); the control unit (51) is configured to be activated when a voltage at the activation terminal (ST) reaches a high level; and the second power connection (T4, T5) and the drive unit (52) are electrically connected through the connection path (L12, L13) which is configured from a branch line branching off from the start signal line (SL1, SL2). [3] Battery unit (U) according to claim 2, wherein the power system is adapted for a vehicle which is equipped with a first start switch (Sa1) that allows the vehicle to be in a first operating state and a second start switch (Sa2) that allows the vehicle to be in a second operating state than the start switch (Sa1, Sa2); the second power terminal (T4, T5) has a first input terminal (T4) which is connected to the first battery (11) via the first start switch (Sa1), and a second input terminal (T5) which is connected to the first battery (11) via the second start switch (Sa2), each of the first and second input terminals (T4, T5) being connected to the activation terminal (ST) via the start signal line (SL1, SL2); and Each of the first and second input terminals (T4, T5) and the drive unit (52) are electrically connected through the connection path (L12, L13). [4] Battery unit (U) according to any one of claims 1 to 3, wherein one end of the connection path (L12, L13) is connected to a connection point (N15, N16) between the second opening / closing unit (61) and the drive unit (52) on the second line path (L11); and the battery unit (U) has a rectifier (D1, D2) on the connection path (L12, L13), wherein the rectifier (D1, D2) limits a current flowing from the connection point (N15, N16) to the second power terminal (T4, T5). [5] Power system equipped with a first battery (11) and a second battery (12) connected in parallel to an electrical load (15, 16), with a start switch (Sa1, Sa2) that starts the power system; and a battery unit (U), wherein the battery unit (U) comprises: a first conductor path (L1 - L4) which is connected to the first battery (11) or the second battery (12) which is used to supply power to the electrical load (15, 16); a first opening / closing unit (31 - 34) provided on the first conductor path (L1 - L4) which enables charging / discharging of the first and second batteries (11, 12) in response to an opening / closing actuation of the first opening / closing unit (31 - 34); a drive unit (52) that opens or closes the first opening / closing unit (31 - 34); a second conductor path (L11) connecting the first battery (11) and the drive unit (52) without one of the start switches (Sa1, Sa2) being located in between; and a second opening / closing unit (61) provided on the second line path (L11), wherein the second opening / closing unit (61) is closed when at least the start switch (Sa1, Sa2) is ON, wherein the first battery (11) and the drive unit (52) are electrically connected by a connection path (L12, L13), and the second line path (L11) is configured from three power supply paths (L11a, L11b, L11c) provided for supplying power to the drive unit (52).

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