CN118613985A - Vehicle-mounted power supply system - Google Patents

Abstract

A vehicle-mounted power supply system (100) comprises a battery (10) and a voltage conversion module (40), wherein when a charger (50) is connected with the battery via the voltage conversion module, a charging voltage from the charger is converted by the voltage conversion module and is supplied to the battery for charging. The voltage conversion module is insulated from a vehicle-side grounding member (G1), the voltage conversion module has a ground line (G2) connected to a charger-side grounding member (G3), a current interruption unit (42) is provided on the ground line, the current interruption unit is configured to interrupt current flow in the ground line when a current equal to or higher than a rated current flows, and the ground line is connected to the vehicle-side grounding member via the current interruption unit.

Description

Vehicle-mounted power supply system

Citation of related application

The present application is based on Japanese patent application No. 2022-012335 filed on 1/28 of 2022, the contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to a vehicle-mounted power supply system.

Background

Conventionally, in an electric vehicle, in order to charge an in-vehicle battery, the in-vehicle battery is connected to an external charger outside the vehicle to perform charging. In addition, in recent years, as the cruising distance of an electric vehicle increases, the battery capacity increases, and therefore, the need for quick charge increases, and the battery voltage increases. However, there is also an external charger that does not correspond to a battery voltage of a high voltage. Therefore, a booster circuit is installed in a vehicle to correspond to such an external charger (for example, patent document 1).

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2020-18078

Disclosure of Invention

In addition, in order to prevent electric shock, the ground (body GND) of the external charger is connected to the ground (body GND) of the vehicle, but if a ground fault occurs on the vehicle side, an overvoltage caused by the vehicle-mounted battery may be applied to the external charger, resulting in a fault of the external charger.

The present disclosure has been made in view of the above-described problems, and an object thereof is to provide a vehicle-mounted power supply system capable of preventing overvoltage from being applied to an external charger when an earth fault occurs.

The vehicle-mounted power supply system for solving the above-described problems includes a battery and a voltage conversion module, wherein when a charger is connected to the battery via the voltage conversion module, a charging voltage from the charger is converted by the voltage conversion module and supplied to the battery to charge the battery, the voltage conversion module is insulated from a vehicle-side grounding member, the voltage conversion module has a ground wire connected to the charger-side grounding member, a current interruption unit is provided in the ground wire, and the current interruption unit cuts off current flow to the ground wire when a current equal to or higher than a rated current flows, and the ground wire is connected to the vehicle-side grounding member via the current interruption unit.

According to the above configuration, even if the positive electrode side power supply path or the negative electrode side power supply path fails to be grounded, the inter-terminal voltage of the battery can be prevented from being applied to the charger via the ground line, and the charger can be prevented from failing.

Drawings

The above objects, other objects, features and advantages of the present disclosure will become more apparent by reference to the accompanying drawings and the following detailed description. The drawings are as follows.

Fig. 1 is a circuit diagram showing an outline of an in-vehicle power supply system and an external charger.

Fig. 2 is a side view schematically showing an arrangement of the in-vehicle charger.

Fig. 3 is a plan view schematically showing the structure of the in-vehicle charger.

Fig. 4 is a graph showing a fuse fusing curve and a varistor breaking curve.

Fig. 5 is a circuit diagram showing a cut state of the relay switch and the fuse.

Fig. 6 is a circuit diagram showing an outline of the vehicle-mounted power supply system according to the second embodiment.

Fig. 7 is a diagram showing the driving timing of the bypass switch in the second embodiment.

Fig. 8 is a circuit diagram showing an outline of the vehicle-mounted power supply system according to the third embodiment.

Fig. 9 is a diagram showing the driving timing of the bypass switch in the third embodiment.

Fig. 10 is a circuit diagram showing an outline of the in-vehicle power supply system according to the fourth embodiment.

Fig. 11 (a) shows the form of the fuse voltage at the time of an insulation failure, and fig. 11 (b) shows the form of the fuse voltage at the time of a disconnection failure.

Fig. 12 is a circuit diagram showing an outline of the vehicle-mounted power supply system according to the modification.

Detailed Description

Hereinafter, a first embodiment in which an "in-vehicle power supply system" is applied to a vehicle (for example, a hybrid vehicle or an electric vehicle) will be described with reference to the drawings. In the following embodiments, the same reference numerals are given to the same or equivalent portions in the drawings, and the description thereof is referred to for the same reference numerals.

(First embodiment)

The in-vehicle power supply system 100 shown in fig. 1 includes a battery pack 10, a leakage detection circuit 20, a switch control device 30, a voltage converter 40, and the like. Although not shown, an electric load such as a rotating motor is connected to the positive-side power supply path L1 and the negative-side power supply path L2 connected to the battery pack 10. The external charger 50 provided outside the vehicle is connected to the voltage converter 40 of the in-vehicle power supply system 100 via the charging cable 60 and the charging plug 70.

The battery pack 10 is a secondary battery having an inter-terminal voltage of 800V, for example. The battery pack 10 is formed by connecting a plurality of battery cells. As the battery cell, for example, a lithium ion battery or a nickel hydrogen battery can be used.

A positive electrode side power supply path L1 connected to the positive electrode side power supply terminal of the battery pack 10 is connected to a positive electrode side terminal of the voltage converter 40. A positive electrode side terminal of an electric load, not shown, is connected to the positive electrode side power supply path L1. The positive electrode side power supply path L1 is electrically insulated from a vehicle-side ground G1 such as a vehicle body (vehicle body). The insulation state (insulation resistance to ground) between the positive-side power supply path L1 and the vehicle-side ground G1 can be expressed as a ground fault resistance Rp1.

Similarly, a negative electrode side power supply path L2 connected to the negative electrode side power supply terminal of the battery pack 10 is connected to the negative electrode side terminal of the voltage converter 40. A negative electrode side terminal of an electric load, not shown, is connected to the negative electrode side power supply path L2. The negative-side power supply path L2 is electrically insulated from the vehicle-side ground G1. The insulating state (ground insulation resistance) between the negative-side power supply path L2 and the vehicle-side ground G1 can be expressed as a ground fault resistance Rn1.

In addition, relay switches DCR for switching between energization and energization interruption with the voltage converter 40 are provided in the positive-side power supply path L1 and the negative-side power supply path L2, respectively. In addition, the relay switch DCR on the positive electrode side may be referred to as a relay switch DCR1, and the relay switch DCR on the negative electrode side may be referred to as a relay switch DCR2. The relay switch DCR1 corresponds to a positive-side power switch unit, and the relay switch DCR2 corresponds to a negative-side power switch unit.

The leakage detection circuit 20 is connected to the positive electrode side power supply path L1 and the negative electrode side power supply path L2, and detects whether the positive electrode side power supply path L1 and the negative electrode side power supply path L2 are normally insulated from the vehicle-side ground contact G1, that is, whether or not a leakage (ground fault) occurs. The leakage detection circuit 20 corresponds to a ground fault detection unit. In the leakage detection circuit 20, a circuit configuration for determining whether or not there is a ground fault may be a well-known configuration, and is not limited to the configuration shown in the drawings. The leakage detection circuit 20 is connected to the switch control device 30.

When the earth leakage detection circuit 20 notifies that the ground fault is detected, the switch control device 30 controls the relay switch DCR to switch the relay switch DCR to the off state (to cut off the energization). The switch control device 30 corresponds to a switch control unit.

Next, the voltage converter 40 will be described.

As shown in fig. 1, the voltage converter 40 includes a booster circuit 41 as a non-insulated converter, in-converter positive-side power supply paths L1 a, L1 b, in-converter negative-side power supply paths L2a, L2b, and the like. The voltage converter 40 corresponds to a voltage conversion module. The booster circuit 41 is connected to the positive-side power supply path L1 and the negative-side power supply path L2 via the intra-converter positive-side power supply path L1 a and the intra-converter negative-side power supply path L2a, respectively. The booster circuit 41 is connected to the charging cable 60 (more specifically, the positive-side charging path 61 and the negative-side charging path 62) via the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2 b.

The voltage converter 40 has a ground line G2 having one end connected to the vehicle-side ground member G1 via a fuse 42 serving as an energization cut-off portion. The other end of the ground line G2 is connected to the charging cable 60. To describe in more detail, the other end of the ground line G2 is connected to the charger-side ground line 63 constituting the charging cable 60 and to the charger-side ground line G3. The charger-side grounding member G3 is a grounding member on the external charger 50 side (main body of the external charger 50, etc.). The fuse 42 blows when a current equal to or greater than a rated current flows, and cuts off the energization of the ground line G2.

As shown in fig. 2 and 3, the voltage converter 40 is mounted in an insulated state with respect to the vehicle-side ground G1. For example, as shown in fig. 2, the voltage converter 40 is housed inside the frame 46 via the insulating sheet 45 and mounted on the vehicle body 200. As shown in fig. 3, a bus bar, a fuse 42, a booster circuit 41, and the like, which are the intra-converter positive-side power supply path L1 a and the intra-converter negative-side power supply path L2a, are housed in the housing 46.

In addition, the insulation state (ground insulation resistance) between the in-converter positive-electrode-side power supply path L1 a and the vehicle-side ground G1 can be represented as a ground fault resistance Rp2, and the insulation state (ground insulation resistance) between the in-converter positive-electrode-side power supply path L1 b and the vehicle-side ground G1 can be represented as a ground fault resistance Rp3.

Similarly, the insulating state (ground insulation resistance) between the in-converter negative electrode side power supply path L2a and the vehicle-side ground G1 can be represented as a ground fault resistance Rn2, and the insulating state (ground insulation resistance) between the in-converter negative electrode side power supply path L2b and the vehicle-side ground G1 can be represented as a ground fault resistance Rn3.

The external charger 50 includes a charging power supply 51, varistors 52a, 52b, and the like. The positive electrode side charging path 61 is connected to the positive electrode terminal of the charging power supply 51, and the negative electrode side charging path 62 is connected to the negative electrode terminal of the charging power supply 51. In the present embodiment, the voltage of the charging power supply 51 (charging voltage) is lower than the inter-terminal voltage (800V) of the battery pack 10 (for example, 400V).

The positive-side charging path 61 and the negative-side charging path 62 are insulated from the charger-side grounding member G3. Therefore, the insulating state (insulation resistance to ground) between the positive-side charging path 61 and the charger-side ground G3 can be expressed as the ground fault resistance Rp4. Similarly, the insulating state (ground insulation resistance) between the negative-side charging path 62 and the charger-side ground G3 can be expressed as a ground fault resistance Rn4.

The positive-side charging path 61 and the negative-side charging path 62 are connected to the charger-side ground G3 via varistors 52a and 52 b. The charging cable 60 is configured by a positive-side charging path 61, a negative-side charging path 62, and a charger-side ground 63 connected to the charger-side ground G3.

As shown in fig. 1, when the charging cable 60 of the external charger 50 is plugged into the charging plug 70 and connected to the in-vehicle power supply system 100, electric power is supplied from the external charger 50. The boosting circuit 41 boosts the charging voltage and supplies the boosted voltage to the battery pack 10. Thereby, the battery pack 10 is charged.

In order to prevent electric shock, the vehicle-side grounding member G1 and the charger-side grounding member G3 are connected via a ground line G2 or the like of the in-vehicle power supply system 100. Therefore, for example, when a ground fault occurs between the positive-side power supply path L1 and the vehicle-side ground G1 (when the ground fault resistance Rp1 becomes small), the inter-terminal voltage of the battery pack 10 is applied to the external charger 50 side via the ground line G2 or the like. In this case, for example, an overvoltage is applied to the varistor 52b connected between the charger-side ground G3 and the negative-side charging path 62.

In addition, when the ground fault occurs, the leakage detection circuit 20 detects that the relay switch DCR is turned off (the energization is turned off), but a relatively long time is required from the occurrence of the ground fault to the detection of the ground fault and the energization is turned off. Therefore, if the time from the occurrence of the ground fault to the interruption of the energization is longer than the time from the application of the overvoltage to the varistor 52b to the occurrence of the fault in the varistor 52b, the fault occurs in the varistor 52 b.

Accordingly, as shown in fig. 1 to 3, the ground line G2 is connected to the vehicle-side ground G1 via the fuse 42 in a state where the voltage converter 40 is insulated from the vehicle-side ground G1. As shown in fig. 4, the rated current IA of the fuse 42 is set lower than the rated current I B of the varistors 52a, 52 b.

As shown in fig. 4, the limit current I C at which the relay switch DCR is turned off is larger than the rated currents IA and I B of the fuse 42 and the varistors 52a and 52 b. The ground fault current ID after the ground fault is larger than the rated currents IA and I B of the fuse 42 and the varistors 52a and 52b and the limit current I C at which the relay switch DCR is turned off.

Fig. 4 shows a fuse 42 fusing curve L10 indicating the product of the time when the fuse 42 fuses and the current, and a varistor 52a, 52b breaking curve L20 indicating the product of the time when the varistors 52a, 52b break and the current. In fig. 4, the horizontal axis represents the current I flowing through the ground line G2, and the vertical axis represents the elapsed time t from the current flowing. As shown in fig. 4, when a ground fault occurs and a ground fault current ID flows, the time TC from the occurrence of the ground fault to the detection of the ground fault and the interruption of the relay switch DCR is longer than the time until the varistors 52a and 52b are broken. But the fuse 42 blows in a time shorter than the time until the varistors 52a, 52b are destroyed. Therefore, the varistors 52a and 52b can be prevented from being broken.

In addition, if the earth fault is detected by the earth leakage detection circuit 20, and the relay switch DCR is turned off by the switch control device 30, the circuit state shown in fig. 5 is set. In addition, fig. 5 omits a part of the circuit configuration, and schematically illustrates the booster circuit 41 as a battery. As shown in fig. 5 (a), even if the operator contacts the vehicle-side earth element G1 and the charger-side earth element G3, the negative-side relay switch DCR2 is turned off, so that the current indicated by the broken line from the battery pack 10 can be prevented from flowing through the negative-side power supply path L2. Similarly, as shown in fig. 5 (b), even if the operator contacts the vehicle-side earth element G1 and the charger-side earth element G3, the relay switch DCR1 on the positive electrode side is turned off, so that the current indicated by the broken line from the external charger 50 can be prevented from flowing through the positive electrode-side power supply path L1.

Effects of the above configuration of the in-vehicle power supply system 100 will be described.

The voltage converter 40 itself is insulated from the vehicle-side ground G1 by an insulating sheet 45, and the ground line G2 is connected to the vehicle-side ground G1 via a fuse 42. Therefore, even if the positive-side power supply path L1 or the negative-side power supply path L2 fails to be grounded, the external charger 50 can be prevented from being failed by the inter-terminal voltage of the battery pack 10 being applied to the external charger 50 via the ground line G2.

When the ground fault is detected by the leakage detection circuit 20, the switch control device 30 controls the relay switch DCR to cut off the energization of the positive-side power supply path L1 and the negative-side power supply path L2. As a result, as shown in fig. 5, even if the operator contacts the vehicle-side grounding member G1 and the charger-side grounding member G3, electric shock can be prevented.

Further, since the voltage converter 40 is mounted on the insulating sheet 45, the internal positive-side power supply paths L1 a and L1 b or the internal negative-side power supply paths L2a and L2b are less likely to be ground fault. Further, even when the insulating sheet 45 is in contact with the housing 46 of the voltage converter 40, electric shock is not easily generated.

(Second embodiment)

A part of the structure of the in-vehicle power supply system 100 in the first embodiment may also be changed. A second embodiment in which a part of the structure of the in-vehicle power supply system 100 is changed will be described.

If a short-circuit fault occurs in the fuse 42 and the current between the vehicle-side earth element G1 and the charger-side earth element G3 cannot be cut off, a large current may continue to flow after the varistor 52b is broken. Therefore, in the second embodiment, the configuration is as follows.

As shown in fig. 6, the voltage converter 40 of the second embodiment includes bypass switches 141a and 141b in the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b, respectively. The bypass switches 141a and 141b are devices that instantaneously and physically shut off the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b. The bypass switches 141a and 141b are connected to the drive circuits 142 of the bypass switches 141a and 141b, and the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b are physically shut off in response to an instruction from the drive circuits 142.

The voltage converter 40 of the second embodiment includes a current sensor 143 as a current detection unit for detecting the current of the negative electrode side power supply path L2b in the converter. The current sensor 143 is connected to the driving circuit 142. When the current sensor 143 detects that a current equal to or greater than the current threshold Th1 flows, the drive circuit 142 controls (drives) the bypass switches 141a and 141b to shut off the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b.

Thus, when the fuse 42 has a short-circuit failure, even if the positive-side power supply path L1 has a ground failure, a large current (a current equal to or greater than a predetermined value) flowing through the negative-side power supply path L2b in the converter can be detected, and the positive-side power supply path L1 b in the converter and the negative-side power supply path L2b in the converter can be cut off by the bypass switches 141a and 141b.

Next, the driving timings of the bypass switches 141a and 141b will be described with reference to fig. 7. In fig. 7, similarly to fig. 5 described in the first embodiment, a fusing curve L10 of the fuse 42, a breaking curve L20 of the varistors 52a, 52b, and the like are described.

As shown in fig. 7, the drive current I E driven by the bypass switches 141a, 141b is greater than the rated current I B of the varistors 52a, 52 b. The time TE until the bypass switches 141a and 141b are driven is earlier than the time TC until the relay switch DCR is turned off, but later than the time when the varistors 52a and 52b are broken. Therefore, if a short-circuit fault occurs in the fuse 42 (the broken line represents the fusing curve L10), the varistors 52a and 52b inevitably break. However, when the varistors 52a, 52b are broken, the bypass switches 141a, 141b are driven earlier than when they are turned off by the relay switch DCR, so that the large current can be prevented from continuing to flow.

According to the configuration of the second embodiment described above, the following effects can be obtained in addition to the effects of the first embodiment.

As described above, the voltage converter 40 has the bypass switches 141a and 141b as the power supply path cut-off portions, and when the current sensor 143 detects a current equal to or greater than the current threshold Th1, the bypass switches 141a and 141b cut off the power supply on the positive-side power supply path L1 b and the negative-side power supply path L2b in the converter and cut off the power supply on the positive-side power supply path L1 and the negative-side power supply path L2. Accordingly, even when the fuse 42 fails in a short circuit and the current flow between the vehicle-side ground G1 and the charger-side ground G3 cannot be cut off, a large current can be prevented from continuing to flow through the ground line G2.

(Third embodiment)

A part of the structure of the in-vehicle power supply system 100 in the first embodiment may also be changed. A third embodiment in which a part of the structure of the in-vehicle power supply system 100 is changed will be described.

As shown in fig. 8, the voltage converter 40 according to the third embodiment includes bypass switches 141a and 141b in the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b, respectively, as in the second embodiment. The third embodiment includes a drive circuit 142 for bypassing the switches 141a and 141b, similarly to the second embodiment.

The voltage converter 40 according to the third embodiment includes a voltage sensor 243 as a voltage detecting unit. The voltage sensor 243 detects the voltage across the fuse 42. When the fuse 42 is cut and a voltage equal to or higher than the voltage threshold Th2 is detected from the voltage sensor 243, the drive circuit 142 controls (drives) the bypass switches 141a and 141b to cut off the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b.

Accordingly, when the current is cut off between the ground line G2 and the vehicle-side ground G1 by the fuse 42, the intra-converter positive-side power supply path L1 b and the intra-converter negative-side power supply path L2b are cut off by the bypass switches 141a and 141 b.

Next, the timing of driving the bypass switches 141a and 141b in the third embodiment will be described with reference to fig. 9. In fig. 9, as in fig. 5 described in the first embodiment, a fusing curve L10 of the fuse 42, a breaking curve L20 of the varistors 52a, 52b, and the like are described. Fig. 9 shows a cut-off curve L30 of the bypass switches 141a, 141b representing the product of time and current when the bypass switches 141a, 141b are driven.

As shown in fig. 9, when a ground fault occurs and the fuse 42 blows, the voltage across the fuse 42 becomes greater than the voltage threshold Th2, and accordingly, the bypass switches 141a and 141b are driven. Therefore, the driving time TF of the bypass switches 141a and 141b is delayed from the time TA at which the fuse 42 is blown.

According to the configuration of the third embodiment described above, in addition to the effects of the first embodiment, the following effects can be obtained.

As shown in fig. 9, following the timing TA at which the fuse 42 is blown, the bypass switches 141a and 141b cut off the positive-side power supply path L1 b and the negative-side power supply path L2b in the converter, and cut off the power supply to the positive-side power supply path L1 and the negative-side power supply path L2. The driving time TF of the bypass switches 141a and 141b is earlier than the time TD until the relay switch DCR is driven by the ground fault detected by the leakage detection circuit 20. Therefore, the time during which an electric shock may occur can be shortened.

(Fourth embodiment)

A part of the structure of the in-vehicle power supply system 100 in the first embodiment may also be changed. A fourth embodiment in which a part of the structure of the in-vehicle power supply system 100 is changed will be described. In the fourth embodiment, the broken line fault and the insulation fault of the fuse 42 can be detected. The following is a detailed description.

As shown in fig. 10, in the in-vehicle power supply system 100 according to the fourth embodiment, a switch S1 as a switching unit for switching between energization and energization interruption is provided between the fuse 42 and the voltage converter 40. The switch S1 is connected to the switch control device 30, and is configured to be switchable by the switch control device 30. In addition, the position of the switch S1 may also be arbitrarily changed, but it is desirable to be close to the fuse 42 in consideration of the possibility of a ground fault occurring inside the voltage converter 40.

In addition, a voltage detection sensor 343 is provided that detects the voltage across the fuse 42 (fuse voltage). The fuse voltage detected by the voltage detection sensor 343 is input to the switch control device 30.

The vehicle-mounted power supply system 100 according to the fourth embodiment includes a potential varying unit that varies a potential (common potential) of the ground line G2 on the fuse 42 side with respect to the switch S1. In the present embodiment, the leak detection circuit 20 is used as a potential varying section. Specifically, the switch control device 30 is configured to be capable of switching on/off the switches Sp and Sn constituting the leak detection circuit 20 and varying the potential of the ground line G2.

Next, a method for detecting an insulation failure will be described.

As shown in fig. 11 (a), switch control device 30 switches Sp and Sn on and off in a state where switch S1 is off. At this time, if an insulation failure does not occur, the fuse voltage detected by the voltage detection sensor 343 fluctuates by a predetermined value or more. On the other hand, in the case of an insulation failure, the fuse voltage detected by the voltage detection sensor 343 does not vary. Therefore, when the switches Sp and Sn are turned on and off while the switch S1 is turned off, the switch control device 30 determines that the fuse is normal when the detected fuse voltage has changed by a predetermined value or more, and determines that an insulation failure has occurred otherwise.

As shown in fig. 11 (b), the switch control device 30 turns on/off the switches Sp and Sn in a state where the switch S1 is turned on. At this time, when the disconnection fault of the fuse 42 does not occur, the fuse voltage detected by the voltage detection sensor 343 does not change. On the other hand, when the disconnection fault occurs, the fuse voltage detected by the voltage detection sensor 343 varies by a predetermined value or more. Therefore, when the switch S1 is turned on and the switches Sp and Sn are turned off, the switch control device 30 determines that a disconnection fault has occurred when the detected fuse voltage has changed by a predetermined value or more, and determines that the fuse voltage is normal otherwise. When it is determined that a failure has occurred, a predetermined process such as notifying the message is performed. As described above, the switch control device 30 according to the fourth embodiment functions as a failure determination unit.

According to the structure of the fourth embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

Since insulation failure and disconnection failure can be detected, safety of the vehicle can be further ensured. In particular, an insulation failure in which the frame of the voltage converter 40 is brought into contact with the vehicle-side ground G1 (vehicle body) due to the breakage of the insulating sheet 45 in the insulation failure can be detected.

The common potential is varied by the leak detection circuit 20. Therefore, these faults can be detected at low cost.

(Modification)

The second embodiment and the third embodiment described above may be combined. That is, the bypass switches 141a and 141b may be driven when a current equal to or greater than the current threshold Th1 is detected by the current sensor 143 or when a voltage equal to or greater than the voltage threshold Th2 is detected by the voltage sensor 243. Thus, the effects of the second embodiment and the third embodiment can be obtained.

Although the bypass switches 141a and 141b are used in the above embodiment, the bypass switches may be changed to magnetic fuses or the like as long as they can cut off a large current without generating an arc.

In the above embodiment, as shown in fig. 12, a zener diode D1 may be provided. Further, by setting the zener voltage of the zener diode D1 to be lower than the varistor voltage of the varistors 52a, 52b, the circulating current at the time of short-circuiting can be prevented from flowing through the varistors 52a, 52b. Therefore, the varistors 52a, 52b can be protected more reliably.

In the above embodiment, if the varistors 52a and 52b can be operated at a high speed to the extent that damage to the varistors is prevented, the fuse 42 may be replaced by a semiconductor switch or the like.

In the fourth embodiment, the circuit configuration of the potential varying section may be arbitrarily changed. Or may be provided separately from the leakage detection circuit 20.

In the above embodiment, the position of the fuse 42 may be arbitrarily changed. May be disposed outside the casing 46 of the voltage converter 40 or inside the casing accommodating the battery pack 10.

In the above embodiment, the installation position of the fuse 42 may be arbitrarily changed. For example, the voltage converter may be disposed inside the housing 46 of the voltage converter 40. Thus, even when a ground fault occurs in the voltage converter 40, the external charger 50 can be protected.

In the second to third embodiments, the positions of the bypass switches 141a and 141b may be changed. For example, the fuse 42 may be provided near the ground line G2. Thereby, the rated current of the bypass switches 141a, 141b can be reduced.

The characteristic structure extracted from each of the above embodiments is described below.

Structure 1

A vehicle-mounted power supply system (100) comprising a battery (10) and a voltage conversion module (40), wherein when a charger (50) and the battery are connected via the voltage conversion module, a charging voltage from the charger is converted by the voltage conversion module and supplied to the battery for charging,

The voltage conversion module is insulated from the vehicle-side grounding member (G1),

The voltage conversion module has a ground line (G2) connected to a charger ground (G3),

The ground wire is provided with an energization breaking unit (42) which breaks energization of the ground wire when a current equal to or greater than a rated current flows, and the ground wire is connected to the vehicle-side ground member via the energization breaking unit.

[ Structure 2]

In addition to the in-vehicle power supply system described in the structure 1, wherein,

The voltage conversion module is connected to a positive electrode side power supply path (L1) and a negative electrode side power supply path (L2) of the storage battery, respectively,

The positive electrode side power supply path is provided with positive electrode side power supply switch parts (DCR, DCR 1) for switching on and off the positive electrode side power supply path,

The negative electrode side power supply path is provided with negative electrode side power supply switch parts (DCR, DCR 2) for switching on and off the negative electrode side power supply path,

The above-mentioned vehicle-mounted power supply system includes:

a ground fault detection unit (20) that determines a ground fault between the positive-side power supply path or the negative-side power supply path and the vehicle-side ground; and

And a switch control unit (30) that controls the positive-side power switch unit and the negative-side power switch unit to cut off the power supply to the positive-side power path and the negative-side power path when the ground fault detection unit detects a ground fault.

[ Structure 3]

The vehicle-mounted power supply system according to the structure 1 or 2, wherein,

The negative electrode side power supply path of the storage battery is provided with a current detection part (143) for detecting the current of the negative electrode side power supply path,

The voltage conversion module includes power supply path cutting units (141 a, 141 b) that cut off the power supply to the positive electrode side power supply path and the negative electrode side power supply path when the current detection unit detects a current equal to or greater than a current threshold (Th 1).

[ Structure 4]

The vehicle-mounted power supply system according to the structure 1 or 2, wherein,

Comprises a voltage detection unit (243) for detecting the voltage across the power-on/off unit in the ground line,

The voltage conversion module includes power supply path shut-off units (141 a, 141 b) that shut off the power supply to the positive-side power supply path and the negative-side power supply path when the voltage detection unit detects a voltage equal to or higher than a voltage threshold (Th 2).

[ Structure 5]

In the vehicle-mounted power supply system according to the structure 4, wherein,

The negative electrode side power supply path of the storage battery is provided with a current detection part (143) for detecting the current of the negative electrode side power supply path,

The power supply path shut-off unit shuts off the current when the voltage detection unit detects a voltage equal to or higher than a voltage threshold or when the current detection unit detects a current equal to or higher than a current threshold.

[ Structure 6]

The vehicle-mounted power supply system according to any one of the configurations 1 to 5, wherein the vehicle-mounted power supply system includes:

A switching unit (S1) which is connected in series to the current interruption unit in the ground line and which is capable of switching between current interruption and current interruption of the ground line;

a voltage detection unit (143) that detects a voltage across the power-on/off unit;

A potential fluctuation unit (20) that fluctuates the potential of the ground line at a position closer to the power-on/off unit than the change-over switch unit; and

And a fault determination unit (30) that determines an insulation fault based on the voltage detected by the voltage detection unit when the potential is changed by the potential change unit in a state in which the energization is turned off by the change switch unit, and determines a disconnection fault of the energization disconnection unit based on the voltage detected by the voltage detection unit when the potential is changed by the potential change unit in a state in which the energization is performed by the change switch unit.

Although the present disclosure has been described based on the embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments, constructions. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and modes, and other combinations and modes including only one element, more than or equal to the element, are also within the scope and spirit of the present disclosure.

Claims (6)

1. A vehicle-mounted power supply system (100) includes a battery (10) and a voltage conversion module (40) by which a charging voltage from a charger (50) is converted and supplied to the battery for charging when the charger and the battery are connected via the voltage conversion module,

The voltage conversion module is insulated with respect to the vehicle-side ground (G1),

The voltage conversion module is provided with a grounding wire (G2) connected with a charger grounding piece (G3),

The ground wire is provided with an energization breaking unit (42) which breaks energization of the ground wire when a current equal to or greater than a rated current flows, and the ground wire is connected to the vehicle-side ground via the energization breaking unit.

2. The vehicle power supply system according to claim 1, wherein,

The voltage conversion module is respectively connected with a positive electrode side power supply path (L1) and a negative electrode side power supply path (L2) of the storage battery,

The positive electrode side power supply path is provided with positive electrode side power supply switch parts (DCR, DCR 1) for switching on and off the positive electrode side power supply path,

The negative electrode side power supply path is provided with negative electrode side power supply switch parts (DCR, DCR 2) for switching on and off the negative electrode side power supply path,

The in-vehicle power supply system includes:

a ground fault detection unit (20) that determines a ground fault between the positive-side power supply path or the negative-side power supply path and the vehicle-side ground; and

And a switch control unit (30) that, when the ground fault detection unit detects a ground fault, controls the positive-side power switch unit and the negative-side power switch unit to cut off the power supply to the positive-side power path and the negative-side power path.

3. The vehicle-mounted power supply system according to claim 1 or 2, wherein,

A current detection unit (143) for detecting the current in the negative electrode side power supply path is provided in the negative electrode side power supply path of the battery,

The voltage conversion module has power supply path shut-off sections (141 a, 141 b) that shut off the power supply to the positive-side power supply path and the negative-side power supply path when the current detection section detects a current equal to or greater than a current threshold (Th 1).

4. The vehicle-mounted power supply system according to claim 1 or 2, wherein,

Comprises a voltage detection unit (243) for detecting the voltage across the power-on/off unit in the ground line,

The voltage conversion module has power supply path shut-off units (141 a, 141 b) that shut off the power supply to the positive-side power supply path and the negative-side power supply path when the voltage equal to or higher than a voltage threshold (Th 2) is detected by the voltage detection unit.

5. The vehicle power supply system according to claim 4, wherein,

A current detection unit (143) for detecting the current in the negative electrode side power supply path is provided in the negative electrode side power supply path of the battery,

The power supply path shut-off unit shuts off the energization when the voltage detection unit detects a voltage equal to or higher than a voltage threshold or when the current detection unit detects a current equal to or higher than a current threshold.

6. The in-vehicle power supply system according to claim 1, characterized in that the in-vehicle power supply system includes:

a switching unit (S1) which is connected in series to the current interruption unit in the ground line and which is capable of switching between current interruption and current interruption of the ground line;

a voltage detection unit (143) that detects a voltage across the power-on/off unit;

a potential fluctuation unit (20) that fluctuates the potential of the ground line at a position closer to the power-on/off unit than the change-over switch unit; and

And a fault determination unit (30) that determines an insulation fault based on the voltage detected by the voltage detection unit when the potential is changed by the potential change unit in a state in which the energization is turned off by the change switch unit, and determines a disconnection fault of the energization disconnection unit based on the voltage detected by the voltage detection unit when the potential is changed by the potential change unit in a state in which the energization is performed by the change switch unit.