WO2021200033A1 - Voltage detection device - Google Patents

Abstract

A voltage detection device (30) is applied to a power source system comprising a storage battery (10) and a plurality of systems (21, 22), the systems being connected in parallel to the storage battery and having inter-terminal voltage of the storage battery respectively applied thereto, and detects the respective applied voltages applied to the systems. The voltage detection device (30) comprises: a first voltage divider circuit which divides the applied voltages of each system by two different voltage dividing ratios; and a detection circuit (50) in which input channels (CH3, CH5) are configured for each system and which detects the applied voltages of each system on the basis of the difference in the two divided voltages input into each input channel. The first voltage divider circuit divides the applied voltages for each input terminal by using voltage dividing ratios that differ in a stepwise manner, and outputs the applied voltages.

Description

Voltage detector Cross-reference of related applications

This application is based on Japanese Application No. 2020-061375, which was filed on March 30, 2020, and the contents of the description are incorporated herein by reference.

The present disclosure relates to a voltage detection device that detects the voltage of a battery.

In recent years, in electric vehicles, a power supply system has been configured in which a function group is divided into a plurality of systems (systems) and the total voltage (voltage between terminals) of an in-vehicle assembled battery is selectively applied to each system by a system relay. ing. In such a power supply system, in order to detect whether or not a voltage is appropriately applied in the selected system, the total voltage applied to the selected system (hereinafter referred to as applied voltage) is detected. There is a need. At that time, it is desirable to enable detection by a common circuit from the viewpoint of cost, and since the total voltage of the in-vehicle assembled battery is generally as high as several hundreds of volts, the applied voltage is divided and detected. It is desirable to do.

Therefore, a method of dividing and detecting the voltage applied to the voltage dividing circuit as shown in Patent Document 1 and a method of measuring the divided voltage via a differential amplifier circuit as shown in Patent Document 2 are adopted. Was supposed to be.

However, in the method of Patent Document 1, the amount of current flowing through the bus bar, which is the detection reference of the applied voltage, is different for each selected circuit, and the potential in each bus bar is different. Then, when the voltage divider voltage is detected by the common circuit, one of the bus bars is used as a reference, which causes a problem that the detection accuracy deteriorates. Further, the method of Patent Document 2 solves the problem that the potentials in each bus bar are different, but in addition to the resistance error of the voltage dividing circuit, the gain error of the differential amplifier circuit overlaps, and the detection accuracy is poor. occured. Therefore, the methods shown in Patent Documents 1 and 2 could not be adopted as they are.

By the way, as shown in Patent Document 3, the monitoring IC that detects each voltage of the battery cells constituting the assembled battery integrates the differential amplifier circuit and the AD conversion device in the monitoring IC, and calibrates or corrects the total error. It is known that the detection accuracy is good because it is suppressed. Therefore, next, it has been considered to divert this monitoring IC to detect each applied voltage.

[Correction under Rule 91 24.03.2021]
Japanese Unexamined Patent Publication No. 2013-162639 Japanese Unexamined Patent Publication No. 2009-236711 Japanese Patent No. 5783197

However, this monitoring IC has been developed specifically for measuring the voltage of each battery cell connected in series. Specifically, it is assumed that the voltage is applied to each input channel of the monitoring IC in the order of the magnitude of the potential, and it is not assumed that the voltage of the same potential is input. Therefore, when the monitoring IC detects a plurality of applied voltages having the same potential, the current wraps around through the protection diodes provided inside and outside the monitoring IC, the value fluctuates, and the detection accuracy deteriorates. occured.

The present disclosure has been made in view of the above circumstances, and its main purpose is to provide a voltage detection device capable of accurately detecting a plurality of applied voltages.

The means for solving the above problems is applied to a power supply system including a storage battery and a plurality of systems connected in parallel to the storage battery and to which a voltage between terminals of the storage battery is applied. In the voltage detection device that detects the applied voltage applied to each system, the first voltage dividing circuit that divides the applied voltage of each system by two different voltage dividing ratios and the input channel for each system are provided. It is provided with a detection circuit that detects the applied voltage of each system based on the difference between the two voltage dividers input from the first voltage divider circuit via the input channel. Each of the input channels has a pair of input terminals, and the first voltage dividing circuit divides the applied voltage at a stepwise different voltage dividing ratio for each of the input terminals and outputs the voltage.

As a result, even if the applied voltage of each system is almost the same, the voltage dividing voltage input to each input terminal of the detection circuit can be gradually increased by the first voltage dividing circuit. Therefore, it is possible to prevent the generation of wraparound current and detect the voltage with high accuracy.

The above objectives and other objectives, features and advantages of the present disclosure will be clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a circuit diagram showing an outline of a power supply system. FIG. 2 is a circuit diagram showing an outline of the monitoring IC. FIG. 3 is a circuit diagram showing an outline of a conventional monitoring IC. FIG. 4 is a circuit diagram showing a wraparound current. FIG. 5 is a circuit diagram showing a current flow. FIG. 6 is a circuit diagram showing a current flow. FIG. 7 is a circuit diagram showing a current flow. FIG. 8 is a circuit diagram showing a current flow. FIG. 9 is a circuit diagram showing a current flow. FIG. 10 is a diagram showing a voltage dividing voltage. FIG. 11 is a diagram showing a voltage dividing voltage. FIG. 12 is a circuit diagram showing an outline of the monitoring IC according to the second embodiment. FIG. 13 is a circuit diagram showing an outline of the monitoring IC according to the third embodiment. FIG. 14 is a circuit diagram showing an outline of the monitoring IC in another example.

Hereinafter, each embodiment that embodies the "voltage detection device" according to the present disclosure will be described with reference to the drawings. In each of the following embodiments, parts that are the same or equal to each other are designated by the same reference numerals in the drawings, and the description thereof will be incorporated for the parts having the same reference numerals. Further, in the description of each embodiment and the modified example, not only the combination of the configurations specified clearly, but also each embodiment and the modified example can be combined as long as the combination does not cause any trouble.

(First Embodiment)
As shown in FIG. 1, the power supply system applied to a vehicle such as an electric vehicle includes an assembled battery 10 as a storage battery, a plurality of systems 21 and 22 configured by grouping functional groups, an assembled battery 10 and each system. Relay switches SN1, SP1, SN2, SP2 as system switch units that switch between energization and de-energization of the power supply paths 23 and 24 between 21 and 22, and voltage detection that detects the voltage applied to each system 21 and 22 The device 30 is provided.

The assembled battery 10 is a series connection of a plurality of battery cells, and the voltage between the terminals between the positive electrode side terminal 10a and the negative electrode side terminal 10b of the assembled battery 10 is, for example, a high voltage of 100 V or more. The assembled battery 10 serves as a power source for an electric load such as a rotating machine (motor generator), and stores electric power generated by regenerative control of the motor generator. In this embodiment, a lithium ion secondary battery is used as the battery cell.

The systems 21 and 22 are connected in parallel to the assembled battery 10, and the voltage between the terminals of the assembled battery 10 is applied to each of them. Examples of the systems 21 and 22 include a drive system including an inverter and a motor, a charging system including a power generation device, and the like.

Power supply paths 23 and 24 are provided for each of the systems 21 and 22. The power supply paths 23 and 24 include positive electrode side power supply paths 23a and 24a connected to the positive electrode side terminal 10a of the assembled battery 10 and negative electrode side power supply paths 23b and 24b connected to the negative electrode side terminal 10b of the assembled battery 10. Is included.

Further, the positive electrode side power supply path 11a is connected to the positive electrode side terminal 10a of the assembled battery 10, and the negative electrode side power supply path 11b is connected to the negative electrode side terminal 10b of the assembled battery 10. Each power supply path 11, 23, 24 is composed of, for example, a bus bar or the like.

Relay switches SN1, SP1, SN2, SP2 are provided for each of the systems 21 and 22. The relay switches SN1, SP1, SN2, SP2 switch between the positive electrode side relay switches SP1 and SP2 for switching the energization and energization cutoff of the positive electrode side power supply paths 23a and 24a and the negative electrode side power supply paths 23b and 24b for energization and energization cutoff. The relay switches SN1 and SN2 on the negative electrode side are included.

When the relay switches SN1 and SP1 are turned off, the power supply between the system 21 and the assembled battery 10 is cut off, and when the relay switches SN1 and SP1 are turned on, the space between the system 21 and the assembled battery 10 is turned on. Is energized. Similarly, when the relay switches SN2 and SP2 are turned off, the energization between the system 22 and the assembled battery 10 is cut off, and when the relay switches SN2 and SP2 are turned on, the system 22 and the assembled battery 10 are turned on. The space between and is energized.

Further, resistors R61 and R62 of about several MΩ are connected in parallel to the relay switches SN1 and SN2 on the negative electrode side, respectively. These resistors R61 and R62 correspond to the connection circuit 70.

The voltage detection device 30 inputs the applied voltage of each system 21 and 22 from the first voltage dividing circuit 40 and the first voltage dividing circuit 40 via the input channels CH1, CH3 and CH5. A monitoring IC 50 as a detection circuit for detecting each applied voltage based on the difference between the two divided voltages, and a second voltage dividing circuit 60 for dividing the voltage between the terminals of the assembled battery 10 are provided.

The first voltage divider circuit 40 includes a first series connector composed of a switch SW0 and resistors R10, R20, R30, a second series connector composed of a switch SW1 and resistors R11, R21, R31, and a switch SW2. And a third series connector composed of resistors R12, R22, R32.

The first series connection body is provided between the positive electrode side power supply path 11a and the negative electrode side power supply path 11b, and is connected in series from the positive electrode side power supply path 11a in the order of switch SW0, resistor R10, resistor R20, and resistor R30. It is connected. The connection point P11 between the resistor R20 and the resistor R30 is connected to the low potential side input terminal S1 of the monitoring IC50, and the connection point P12 between the resistor R10 and the resistor R20 is the high potential side input of the monitoring IC50. It is connected to the terminal V1.

As a result, when the switch SW0 is turned on, the voltage between the terminals is divided by the first voltage division ratio (R30 / (R10 + R20 + R30)) and input to the input terminal S1. When the switch SW0 is turned on, the voltage between the terminals is divided by the second voltage division ratio ((R30 + R20) / (R10 + R20 + R30)) and input to the input terminal V1. The voltage dividing voltage in which the terminal voltage is divided by the first voltage dividing ratio is indicated as the voltage dividing voltage DS1, and the voltage dividing voltage in which the terminal voltage is divided by the second voltage dividing ratio is referred to as the voltage dividing voltage. It may be indicated as DV1.

Further, as shown in FIG. 2, between the electric path between the connection point P11 and the low potential side input terminal S1 and the electric path between the connection point P12 and the high potential side input terminal V1, as shown in FIG. Protective elements and filters are provided. For example, a diode D11 is provided that allows the flow of current from the low potential side input terminal S1 side to the high potential side input terminal V1 side.

The second series connection is provided between the positive electrode side power supply path 23a and the negative electrode side power supply path 23b of the system 21, and the switch SW1, the resistor R11, the resistor R21, and the resistor R31 are in this order from the positive electrode side power supply path 23a. Are connected in series with. The connection point P13 between the resistor R21 and the resistor R31 is connected to the low potential side input terminal S3 of the monitoring IC50, and the connection point P14 between the resistor R11 and the resistor R21 is the high potential side input of the monitoring IC50. It is connected to the terminal V3.

As a result, when the relay switches SN1 and SP1 and the switch SW1 are turned on, the voltage applied to the system 21 is divided by the third voltage division ratio (R31 / (R11 + R21 + R31)) and input to the input terminal S3. When the relay switches SN1, SP1 and the switch SW1 are turned on, the voltage applied to the system 21 is divided by the fourth voltage division ratio ((R31 + R21) / (R11 + R21 + R31)) and input to the input terminal V3. ..

The voltage applied to the system 21 is the potential difference (voltage) actually generated between the positive electrode side power supply path 23a and the negative electrode side power supply path 23b due to the application of the voltage between the terminals of the assembled battery 10. That is. Further, the voltage dividing voltage in which the voltage applied to the system 21 is divided by the third voltage dividing ratio is indicated as the voltage dividing voltage DS3, and the voltage applied to the system 21 is divided by the fourth voltage dividing ratio. The voltage may be referred to as a voltage divider voltage DV3.

Further, as shown in FIG. 2, between the electric path between the connection point P13 and the low potential side input terminal S3 and the electric path between the connection point P14 and the high potential side input terminal V3, as shown in FIG. Protective elements and filters are provided. For example, a diode D13 that allows the flow of current from the side of the low potential side input terminal S3 to the side of the high potential side input terminal V3 is provided.

The third series connection is provided between the positive electrode side power supply path 24a and the negative electrode side power supply path 24b of the system 22, and the switch SW2, the resistor R12, the resistor R22, and the resistor R32 are in this order from the positive electrode side power supply path 24a. Are connected in series with. The connection point P15 between the resistor R22 and the resistor R32 is connected to the low potential side input terminal S5 of the monitoring IC50, and the connection point P16 between the resistor R12 and the resistor R22 is the high potential side input of the monitoring IC50. It is connected to terminal V5.

As a result, when the relay switches SN2 and SP2 and the switch SW2 are turned on, the voltage applied to the system 22 is divided by the fifth voltage division ratio (R32 / (R12 + R22 + R32)) and input to the input terminal S5. When the relay switches SN2 and SP2 and the switch SW2 are turned on, the voltage applied to the system 22 is divided by the sixth voltage division ratio ((R32 + R22) / (R12 + R22 + R32)) and input to the input terminal V5. ..

The voltage applied to the system 22 is the potential difference (voltage) actually generated between the positive electrode side power supply path 24a and the negative electrode side power supply path 24b due to the application of the voltage between the terminals of the assembled battery 10. That is. Further, the voltage dividing voltage in which the voltage applied to the system 22 is divided by the fifth voltage dividing ratio is indicated as the voltage dividing voltage DS5, and the voltage applied to the system 22 is divided by the sixth voltage dividing ratio. The voltage may be referred to as a voltage divider voltage DV5.

Further, as shown in FIG. 2, between the electric path between the connection point P15 and the low potential side input terminal S5 and the electric path between the connection point P16 and the high potential side input terminal V5, as shown in FIG. Protective elements and filters are provided. For example, a diode D15 that allows the flow of current from the low potential side input terminal S5 side to the high potential side input terminal V5 side is provided.

As shown in FIG. 2, the monitoring IC50 uses one having at least six input channels CH1 to CH6, but more input channel CHs including the input channel CH6 are input in the same manner as the input channel CH6. Since the terminals are short-circuited and are not used for the voltage detection this time, they will be described in the range of input channels CH1 to CH6 in the following description. Each input channel CH1 to CH6 has a pair of input terminals (pin terminals) S1 to S6 and V1 to V6, respectively. The pair of input terminals S1 to S6 and V1 to V6 have high potential side input terminals V1 to V6 and low potential side input terminals S1 to S6. The input channels CH1 to CH6 are arranged in order from the one with the smallest number, that is, in the order of CH1 → CH2 → ... → CH6. Further, in each of the input channels CH1 to CH6, the low potential side input terminals S1 to S6 → the high potential side input terminals V1 to V6 are arranged in this order. Therefore, the input terminals S1 to S6 and V1 to V6 are arranged in the order of S1 → V1 → S2 → V2 → ... → S6 → V6.

The monitoring IC 50 includes a multiplexer 51, a differential amplifier circuit 52, an AD converter 53, and semiconductor switches SW51 to SW56 such as MOSFETs. The input terminals S1 to S6 and V1 to V6 are connected to the differential amplifier circuit 52 via a multiplexer 51. Specifically, the high potential side input terminals V1 to V6 are connected to the non-inverting input terminal side of the differential amplifier circuit 52 via the multiplexer 51, and the low potential side input terminals S1 to S6 are connected via the multiplexer 51. The inverting input terminal side of the differential amplifier circuit 52 is connected.

The multiplexer 51 outputs the voltage input to the input terminals S1 to S6 and V1 to V6 of the input channels CH1 to CH6 selected from the input channels CH1 to CH6 to the differential amplifier circuit 52.

The differential amplifier circuit 52 detects the voltage (potential difference) between the non-inverting input terminal and the inverting input terminal and outputs it as an analog signal to the AD converter 53. The AD converter 53 converts the analog signal into a digital signal and outputs it to the arithmetic unit 54 included in the monitoring IC 50. The arithmetic unit 54 calculates the voltage between the terminals of the assembled battery 10 and the voltage applied to each of the systems 21 and 22 based on the input potential difference (digital signal).

Specifically, the arithmetic unit 54 has a first voltage dividing ratio (R30 / (R10 + R20 + R30)), a second voltage dividing ratio ((R30 + R20) / (R10 + R20 + R30)), and a voltage dividing circuit 40 of the first voltage dividing circuit 40 with respect to the voltage between terminals. The voltage between terminals is calculated based on the potential difference between the voltage dividing voltage DS1 and the voltage dividing voltage DV1. In the monitoring IC 50 of the present embodiment, the differential amplifier circuit 52 and the AD converter 53 are integrated in the monitoring IC 50, and the total error is suppressed by calibration or correction. Therefore, the voltage between terminals can be calculated accurately.

Similarly, the arithmetic unit 54 has a third voltage dividing ratio (R31 / (R11 + R21 + R31)), a fourth voltage dividing ratio ((R31 + R21) / (R11 + R21 + R31)) of the first voltage dividing circuit 40 with respect to the voltage applied to the system 21. And the voltage applied to the system 21 is calculated based on the potential difference between the voltage dividing voltage DS3 and the voltage dividing voltage DV3. The calculation of the voltage applied to the system 22 is the same. It is not necessary to provide the arithmetic unit 54 in the monitoring IC 50, and the arithmetic unit 54 may be provided in the external device.

The semiconductor switches SW51 to SW56 are provided so as to be able to switch between energization and energization cutoff between the adjacent low potential side input terminals S1 to S6, respectively. For example, the semiconductor switch SW51 is provided between the input terminal S1 and the input terminal S2, and is configured to be able to switch between energization and energization cutoff between the terminals. The same applies to the semiconductor switches SW52 to SW56.

Also, diodes D51 to D56 are connected in parallel to the semiconductor switches SW51 to SW56, respectively. The diodes D51 to D56 may be parasitic diodes of the semiconductor switches SW51 to SW56. Each diode D51 is arranged so as to allow current to flow from the low-potential side input terminal S1 having a small number to the low-potential side input terminal S2 having a large number. The same applies to the diodes D52 to D56.

The arithmetic unit 54 is configured to be able to control the switching of the semiconductor switches SW51 to SW56 and the selection of the input channels CH1 to CH6 by the multiplexer 51 in addition to the above-described arithmetic.

In the second voltage dividing circuit 60, the switch SW3, the resistor R42, and the resistor R52 are connected in series in this order between the positive electrode side power supply path 11a and the negative electrode side power supply path 11b. Further, one end of the series connector of the resistor R41 and the resistor R51 is connected between the switch SW3 and the resistor R42 so as to be parallel to the resistor R42 and the resistor R52, and the other end is connected to the negative electrode side power supply path 11b. Has been done.

The connection point P21 between the resistor R41 and the resistor R51 is connected to the connection point P13 between the resistor R21 and the resistor R31 of the first voltage dividing circuit 40 via the diode D1. The diode D1 is connected so as to allow the flow of current from the side of the second voltage divider circuit 60 to the side of the first voltage divider circuit 40. That is, when the switch SW3 is turned on, the voltage between the terminals of the assembled battery 10 is divided by the seventh voltage dividing ratio (R51 / (R41 + R51)) based on the resistors R41 and R51, and the connection point P13 is divided via the diode D1. It is configured to be applicable to. The voltage divider voltage obtained by dividing the voltage between terminals by the seventh voltage divider ratio may be referred to as the voltage divider voltage DSmin3.

The connection point P22 between the resistor R42 and the resistor R52 is connected to the connection point P15 between the resistor R22 and the resistor R32 of the first voltage dividing circuit 40 via the diode D2. The diode D2 is connected so as to allow the flow of current from the side of the second voltage divider circuit 60 to the side of the first voltage divider circuit 40. That is, when the switch SW3 is turned on, the voltage between the terminals of the assembled battery 10 is divided by the eighth voltage dividing ratio (R52 / (R42 + R52)) based on the resistors R42 and R52, and the connection point P15 is divided via the diode D2. It is configured to be applicable to. The voltage divider voltage obtained by dividing the voltage between terminals by the eighth voltage divider ratio may be referred to as the voltage divider voltage DSmin5.

By the way, as shown in FIG. 3, the monitoring IC50 is originally used to detect the voltage of each battery cell C11 to C15 constituting the assembled battery. The semiconductor switches SW51 to SW55 are provided for equalization discharge of the battery cells C11 to C15. That is, the monitoring IC50 has been developed on the premise of detecting the voltage of the battery cells C11 to C15 connected in series. Therefore, for example, the circuit configuration is set on the premise that the potential increases stepwise for each of the input channels CH1 to CH5. Specifically, the potential input in the order of input terminal S1 → input terminal V1, S2 → input terminal V2, S3 → input terminal V3, S4 → input terminal V4, S5 → input terminal V5 gradually increases. Is assumed.

Therefore, when trying to detect the voltage of the same potential, as shown in FIG. 4, the voltage between the terminals of the assembled battery 10 and the applied voltage of the systems 21 and 22 are set to each input channel CH11, via a voltage dividing circuit. When inputting to CH13 and CH15, there are the following problems. That is, when the voltages input to the input channels CH11, CH13, and CH15 are substantially the same, the diodes D11, D13, D15, or the diodes D11, D13, D15, or the diodes D11, D13, D15, provided outside the monitoring IC50, are provided as shown by the broken line arrows shown in FIG. A wraparound current may be generated via the diodes D51 to D56 of the semiconductor switches SW51 to SW56 inside the monitoring IC50.

Further, when the input voltage to the input channel CH11 is larger than the input voltage to the input channels CH13 and CH15, a wraparound current may occur. Further, when the relay switches SN1, SP1, SN2, and SP2 are turned off and the applied voltage of any of the systems 21 and 22 becomes zero, a wraparound current may be generated in the same manner. This causes a problem that a voltage detection error occurs.

Therefore, the first voltage dividing circuit 40 and the second voltage dividing circuit 60 are provided, and each voltage dividing ratio is set as described below. The details will be described below.

As shown in FIGS. 1 and 2, input channels CH1, CH3, and CH5 are set for the assembled battery 10, the systems 21, and 22, respectively. Then, the first voltage dividing circuit 40 divides the voltage for each input terminal S1, V1, S3, V3, S5, V5 of the input channels CH1, CH3, CH5 in a stepwise different voltage dividing ratio, and outputs the voltage. I try to do it. More specifically, each voltage dividing ratio of the first voltage dividing circuit 40 is set so that the input potential increases stepwise in the order of input terminal S1 → V1 → S3 → V3 → S5 → V5.

Specifically, in the first voltage dividing circuit 40, the second voltage dividing ratio of the voltage dividing voltage DV1 that can be input to the high potential side input terminal V1 of the input channel CH1 is the low potential side input terminal of the input channel CH1. It is set one step larger than the first voltage dividing ratio of the voltage dividing voltage DS1 that can be input to S1. Similarly, in the input channels CH3 and CH5, the fourth voltage division ratio is set one step larger than the third voltage division ratio, and the sixth voltage division ratio is set one step larger than the fifth voltage division ratio. ing.

Further, among the input channels CH1, CH3, and CH5 used for voltage detection, between the input channel CH1 and the input channel CH3 to be set next to each other, and between the input channel CH3 and the input channel CH5, The voltage division ratio is set stepwise so that a potential difference of a predetermined value or more occurs in the input potential. That is, in the first voltage dividing circuit 40, the third voltage dividing ratio of the voltage dividing voltage DS3 that can be input to the low potential side input terminal S3 of the input channel CH3 can be input to the high potential side input terminal V1 of the input channel CH1. The voltage dividing voltage is set one step larger than the second voltage dividing ratio of the DV1. Similarly, the fifth voltage division ratio is set one step larger than the fourth voltage division ratio.

That is, the first pressure dividing ratio (R30 / (R10 + R20 + R30)) <second pressure dividing ratio (R (30 + R20) / (R10 + R20 + R30)) <third pressure dividing ratio (R31 / (R11 + R21 + R31)) <fourth pressure dividing ratio ( Each voltage division ratio is set stepwise so that (R31 + R21) / (R11 + R21 + R31)) <fifth voltage division ratio (R32 / (R12 + R22 + R32)) <sixth voltage division ratio ((R32 + R22) / (R12 + R22 + R32)). There is. Then, the values of the resistors R10, R20, R30, R11, R21, R31, R12, R22, and R32 are set so that the voltage division ratios are set stepwise.

Further, a voltage drop occurs depending on the current flowing in each of the negative electrode side power supply paths 11b, 23b, 24b. For example, when charging the assembled battery 10, a voltage drop occurs due to the charging current. Therefore, the first voltage dividing ratio, the third voltage dividing ratio, and the fifth voltage dividing ratio in the first voltage dividing circuit 40 are voltage drops calculated based on the current amount and impedance of the negative electrode side power supply paths 11b, 23b, and 24b. It is set in consideration of the amount.

Specifically, the maximum drop amounts N0max, N1max, and N2max from the circuit reference (N0) of the monitoring IC50 are calculated from the impedance with the current amounts of the negative electrode side power supply paths 11b, 23b, and 24b, respectively. Then, the first voltage dividing ratio is set so that the maximum drop amount N0max <voltage dividing voltage DS1. Similarly, the third voltage dividing ratio is set so that the maximum drop amount N1max <voltage dividing voltage DS3. Similarly, the fifth voltage dividing ratio is set so that the maximum drop amount N2max <voltage dividing voltage DS5.

Further, the second voltage dividing circuit 60 is configured to divide the voltage between terminals at stepwise different voltage dividing ratios for each of the systems 21 and 22. Specifically, the seventh voltage dividing ratio (R51 / (R41 + R51)) of the voltage dividing voltage DSmin3 is smaller than the third voltage dividing ratio (R31 / (R11 + R21 + R31)) of the voltage dividing voltage DS3, and the first voltage dividing circuit. At 40, it is set larger than the second voltage dividing ratio ((R30 + R20) / (R10 + R20 + R30)) which is one step smaller than the third voltage dividing ratio.

Further, the eighth voltage dividing ratio (R52 / (R42 + R52)) of the voltage dividing voltage DSmin5 is smaller than the fifth voltage dividing ratio (R32 / (R12 + R22 + R32)) of the voltage dividing voltage DS5, and the first voltage dividing circuit 40 Is set larger than the fourth voltage dividing ratio ((R31 + R21) / (R11 + R21 + R31)), which is one step smaller than the fifth voltage dividing ratio.

Then, the second voltage dividing circuit 60 is set for the systems 21 and 22 when there is a system 21 or 22 in which the energization with the assembled battery 10 is cut off by the relay switches SN1, SP1, SN2, SP2. It is configured to output the voltage dividing voltages DSmin3 and DSmin5 to the low potential side input terminals S3 and S5 of the input channels CH3 and CH5.

Specifically, the connection point P21 between the resistor R41 and the resistor R51 is connected to the connection point P13 between the resistor R21 and the resistor R31 of the first voltage dividing circuit 40 via the diode D1. Therefore, in the second voltage dividing circuit 60, when the applied voltage of the system 21 becomes zero, the voltage dividing voltage DS3 also becomes zero, so that the voltage dividing voltage DSmin3 is input to the low potential side input terminal S3 via the diode D1. Will be output to. Similarly, the connection point P22 between the resistor R42 and the resistor R52 is connected to the connection point P15 between the resistor R22 and the resistor R32 of the first voltage dividing circuit 40 via the diode D2. Therefore, when the applied voltage of the system 22 becomes zero, the second voltage dividing circuit 60 outputs the voltage dividing voltage DSmin5 to the low potential side input terminal S5 via the diode D2.

Next, the operation of the voltage detection device 30 will be described with reference to FIGS. 5 to 9.

FIG. 5 is a diagram showing the operation of the voltage detection device 30 and the current flow when the relay switches SN1, SP1, SN2, and SP2 are turned on. In FIG. 5, the broken line shows the current flow.

As shown in FIG. 5, a voltage dividing voltage DS1 in which the voltage between the terminals is divided by the first voltage dividing ratio is input to the input terminal S1. The voltage dividing voltage DV1 in which the voltage between the terminals is divided by the second voltage dividing ratio is input to the input terminal V1. The voltage divider voltage DS3 in which the voltage applied to the system 21 is divided by the third voltage divider ratio is input to the input terminal S3. The voltage dividing voltage DV3 in which the voltage applied to the system 21 is divided by the fourth voltage dividing ratio is input to the input terminal V3. The voltage divider voltage DS5 in which the voltage applied to the system 22 is divided by the fifth voltage divider ratio is input to the input terminal S5. The voltage dividing voltage DV5 in which the voltage applied to the system 22 is divided by the sixth voltage dividing ratio is input to the input terminal V5. The magnitude relationship of each voltage dividing voltage is DS1 <DV1 <DS3 <DV3 <DS5 <DV5.

As a result, the voltage dividing voltage that is input stepwise in the order of input terminal S1 → input terminal V1 → input terminal S3 → input terminal V3 → input terminal S5 → input terminal V5 increases. Therefore, it is possible to prevent the current from wrapping around through the diodes D11, D13, D15, D51, D53, and D55.

Therefore, the monitoring IC50 can accurately detect the voltage between terminals based on the two voltage dividing voltages DS1 and DV1 input to the input terminals S1 and V1. Similarly, the monitoring IC 50 can accurately detect the voltage applied to the system 21 based on the two voltage dividing voltages DS3 and DV3 input to the input terminals S3 and V3. The voltage applied to the system 22 can be detected with high accuracy as well.

The seventh voltage dividing ratio in the second voltage dividing circuit 60 is smaller than the third voltage dividing ratio in the first voltage dividing circuit 40, and the voltage between terminals and the voltage applied to the system 21 are almost the same. Therefore, the voltage dividing voltage DSmin3 obtained by dividing the voltage between terminals by the seventh voltage dividing ratio is smaller than the voltage dividing voltage DS3 obtained by dividing the voltage applied to the system 21 by the third voltage dividing ratio. Therefore, the voltage dividing voltage DSmin3 from the second voltage dividing circuit 60 is not input to the input terminal S3, and the voltage dividing voltage DS3 from the first voltage dividing circuit 40 is input to the input terminal S3.

Similarly, the eighth voltage dividing ratio in the second voltage dividing circuit 60 is smaller than the fifth voltage dividing ratio in the first voltage dividing circuit 40, and the voltage between terminals and the voltage applied to the system 22 are almost the same. Therefore, the voltage dividing voltage DSmin5 obtained by dividing the voltage between terminals by the eighth voltage dividing ratio is smaller than the voltage dividing voltage DS5 obtained by dividing the voltage applied to the system 22 by the fifth voltage dividing ratio. Therefore, the voltage dividing voltage DSmin5 from the second voltage dividing circuit 60 is not input to the input terminal S5, and the voltage dividing voltage DS3 from the first voltage dividing circuit 40 is input to the input terminal S5.

FIG. 6 is a diagram showing the operation of the voltage detection device 30 and the current flow when the relay switches SN1 and SP1 are turned off and the relay switches SN2 and SP2 are turned on. In FIG. 5, the broken line indicates the current in the first voltage dividing circuit 40. Further, the alternate long and short dash line indicates the current in the second voltage dividing circuit 60.

As shown in FIG. 6, a voltage dividing voltage DS1 in which the voltage between the terminals is divided by the first voltage dividing ratio is input to the input terminal S1. The voltage dividing voltage DV1 in which the voltage between the terminals is divided by the second voltage dividing ratio is input to the input terminal V1. The voltage divider voltage DS5 in which the voltage applied to the system 22 is divided by the fifth voltage divider ratio is input to the input terminal S5. The voltage dividing voltage DV5 in which the voltage applied to the system 22 is divided by the sixth voltage dividing ratio is input to the input terminal V5.

On the other hand, since the energization from the assembled battery 10 to the system 21 is cut off by the premise, the voltage applied to the system 21 is 0V. Therefore, the voltage dividing voltage by the first voltage dividing circuit 40 is also 0V. Therefore, since the voltage dividing voltage DSmin3 by the second voltage dividing circuit 60 is higher than 0V, as shown by the one-point chain line, the positive electrode side terminal 10a of the assembled battery 10 → switch SW3 → resistor R41 → diode D1 → resistor R31 → Resistance R61 → Current flows through the path of the negative electrode side terminal 10b of the assembled battery 10.

As a result, the voltage dividing voltage DSmin3 in which the voltage between the terminals is divided by the seventh voltage dividing ratio is input to the input terminal S3. The voltage dividing voltage DSmin3 is input to the input terminal V3 via the diode D13. The magnitude relationship of each voltage dividing voltage is DS1 <DV1 <DSmin3 <DS5 <DV5.

As a result, the voltage dividing voltage that is input stepwise in the order of input terminal S1 → input terminal V1 → input terminal S3, V3 → input terminal S5 → input terminal V5 increases. Therefore, it is possible to prevent the current from wrapping around through the diodes D11, D13, D15, D51, D53, and D55. Therefore, the monitoring IC 50 can accurately detect the voltage between terminals and the voltage applied to the system 22.

FIG. 7 is a diagram showing the operation of the voltage detection device 30 and the current flow when the relay switches SN2 and SP2 are turned off and the relay switches SN1 and SP1 are turned on. In FIG. 7, the broken line indicates the current in the first voltage dividing circuit 40. Further, the alternate long and short dash line indicates the current in the second voltage dividing circuit 60.

As shown in FIG. 7, a voltage dividing voltage DS1 in which the voltage between the terminals is divided by the first voltage dividing ratio is input to the input terminal S1. The voltage dividing voltage DV1 in which the voltage between the terminals is divided by the second voltage dividing ratio is input to the input terminal V1. The voltage divider voltage DS3 in which the voltage applied to the system 21 is divided by the third voltage divider ratio is input to the input terminal S3. The voltage dividing voltage DV3 in which the voltage applied to the system 21 is divided by the fourth voltage dividing ratio is input to the input terminal V3.

On the other hand, since the energization from the assembled battery 10 to the system 22 is cut off by the premise, the voltage between the terminals S5 and V5 is divided by the eighth voltage division ratio for the same reason as described in FIG. The divided voltage divider voltage DSmin5 is input. The magnitude relationship of each voltage dividing voltage is DS1 <DV1 <DS3 <DV3 <DSmin5.

As a result, the voltage dividing voltage that is input stepwise in the order of input terminal S1 → input terminal V1 → input terminal S3 → input terminal V3 → input terminals S5 and V5 increases. Therefore, it is possible to prevent the current from wrapping around through the diodes D11, D13, D15, D51, D53, and D55. Therefore, the monitoring IC 50 can accurately detect the voltage between terminals and the voltage applied to the system 22.

FIG. 8 is a diagram showing the operation of the voltage detection device 30 and the current flow when the relay switches SN1, SP1, SN2, and SP2 are turned on and the switch SW0 is stuck off (cannot be turned on). In FIG. 8, the broken line shows the current flow.

As shown in FIG. 8, the voltage divider voltage DS3 in which the voltage applied to the system 21 is divided by the third voltage divider ratio is input to the input terminal S3. The voltage dividing voltage DV3 in which the voltage applied to the system 21 is divided by the fourth voltage dividing ratio is input to the input terminal V3. The voltage divider voltage DS5 in which the voltage applied to the system 22 is divided by the fifth voltage divider ratio is input to the input terminal S5. The voltage dividing voltage DV5 in which the voltage applied to the system 22 is divided by the sixth voltage dividing ratio is input to the input terminal V5. On the other hand, since the switch SW0 cannot be turned on, the input terminals S1 and V1 have the same potential as the negative electrode side power supply path 11b, that is, 0V.

As a result, the voltage dividing voltage that is input stepwise in the order of input terminal S1, V1 (= 0V) → input terminal S3 → input terminal V3 → input terminal S5 → input terminal V5 increases. Therefore, it is possible to prevent the current from wrapping around through the diodes D11, D13, D15, D51, D53, and D55. Therefore, the monitoring IC 50 can accurately detect the voltage applied to the systems 21 and 22. Further, the monitoring IC50 can detect a failure of the switch SW0.

FIG. 9 is a diagram showing the operation of the voltage detection device 30 and the current flow when the relay switches SN1, SP1, SN2, and SP2 are turned off. In FIG. 9, the current in the second voltage dividing circuit 60 is shown by the alternate long and short dash line.

As shown in FIG. 9, the voltage dividing voltage DS1 in which the voltage between the terminals is divided by the first voltage dividing ratio is input to the input terminal S1. The voltage dividing voltage DV1 in which the voltage between the terminals is divided by the second voltage dividing ratio is input to the input terminal V1.

On the other hand, since the energization from the assembled battery 10 to the systems 21 and 22 is cut off by the premise, the voltage between the terminals S3 and V3 is divided by the seventh voltage dividing ratio for the same reason as described above. The compressed voltage divider voltage DSmin3 is input. Further, the voltage dividing voltage DSmin5 in which the voltage between the terminals is divided by the eighth voltage dividing ratio is input to the input terminals S5 and V5. The magnitude relationship of each voltage dividing voltage is DS1 <DV1 <DSmin3 <DSmin5.

As a result, the voltage dividing voltage that is input stepwise in the order of input terminal S1 → input terminal V1 → input terminal S3, V3 → input terminal S5, V5 increases. Therefore, it is possible to prevent the current from wrapping around through the diodes D11, D13, D15, D51, D53, and D55. Therefore, the monitoring IC 50 can accurately detect the voltage between terminals.

According to the configuration of the first embodiment, the following effects can be obtained.

In the first voltage dividing circuit 40, the voltage between terminals or the system 21 has a voltage dividing ratio (first voltage dividing ratio to sixth voltage dividing ratio) that is stepwise different for each input terminal S1, V1, S3, V3, S5, V6. , 22 The applied voltage is divided and output. As a result, even if the voltage between the terminals and the applied voltage of each system 21 and 22 are almost the same, the amount input to each input terminal S1, V1, S3, V3, S5, V6 by the first voltage dividing circuit 40. The pressure voltage can be increased stepwise. Therefore, as shown in FIG. 5, it is possible to prevent the generation of wraparound current and detect the voltage with high accuracy.

The second voltage divider circuit 60 divides the voltage between terminals at stepwise different voltage divider ratios (seventh voltage divider ratio and eighth voltage divider ratio) for each of the systems 21 and 22. Then, in the second voltage dividing circuit 60, when there are systems 21 and 22 in which the energization with the assembled battery 10 is cut off, the voltage dividing voltage is applied to the input channels CH3 and CH5 set for the systems 21 and 22. Outputs DSmin3 and DSmin5.

Further, the seventh voltage dividing ratio by the second voltage dividing circuit 60 is smaller than the third voltage dividing ratio by the first voltage dividing circuit 40, and the second voltage dividing ratio is one step smaller than the third voltage dividing ratio. It is set larger than the pressure ratio. As a result, the magnitude relationship of the voltage dividing voltage becomes DV1 <DSmin3 <DS3. Therefore, as shown in FIG. 6, the voltage dividing voltage DSmin3 is input to the input terminals S3 and V3 only when the relay switches SN1 and SP1 are turned off. Further, in this case, since the voltage dividing voltage DSmin3 input to the input terminal S3 is larger than the voltage dividing voltage DV1 input to the input terminal V1, a wraparound current from the input terminal V1 to the input terminal S3 is generated. Can be prevented. Further, DSmin3 <DS5, and the voltage dividing voltage DS5 input to the input terminal S5 is larger than the voltage dividing voltage DSmin3 input to the input terminals S3 and V3. Therefore, from the input terminals S3 and V3 to the input terminal S5. It is possible to prevent the wraparound current from being generated.

Similarly, as shown in FIG. 7, the wraparound current can be prevented even when the relay switches SN2 and SP2 are turned off. Further, since DSmin3 <DSmin5, as shown in FIG. 9, even when all the relay switches SN1, SP1, SN2, and SP2 are off, the current wraps around from the input channel CH1 to the input channels CH3 and SH5. Can be prevented.

The third voltage dividing ratio and the fifth voltage dividing ratio in the first voltage dividing circuit 40 are set in consideration of the amount of voltage drop. Specifically, the third voltage dividing ratio is set so that the maximum drop amount N1max <voltage dividing voltage DS3, and the fifth voltage dividing ratio is set so that the maximum dropping amount N2max <voltage dividing voltage DS5. ing. As a result, even if a voltage drop occurs, no negative voltage is generated, and the voltage dividing voltage input to each input terminal S1, V1, S3, V3, S5, V6 can be gradually increased, resulting in wraparound. The current can be prevented.

Further, the first voltage dividing circuit 40 divides the voltage between terminals by two different voltage dividing ratios, and the monitoring IC 50 has two voltage dividing voltages DS1 via the input channel CH1 set for the assembled battery 10. DV1 is input, and the voltage between terminals is detected based on the difference between the divided voltages DS1 and DV1. Therefore, the applied voltage and the circuit for detecting the voltage between terminals can be shared. Further, as shown in FIG. 8, it is possible to detect the off sticking of the switch SW0.

Since the voltage dividing voltage is input to the monitoring IC50, the withstand voltage can be reduced and the size can be reduced. Further, since the differential amplifier circuit 52 and the AD converter 53 are integrated inside the monitoring IC 50 and the arithmetic unit 54 corrects the error, the detection accuracy can be improved. Further, since the monitoring IC50 used for voltage detection of the battery cell of the assembled battery can be adopted as it is, the development cost can be suppressed.

The first to sixth voltage division ratios are set in stages. Further, the seventh pressure division ratio is set between the second pressure division ratio and the third pressure division ratio, and the eighth pressure division ratio is between the fourth pressure division ratio and the fifth pressure division ratio. Is set to. As a result, as shown in FIG. 10, each voltage dividing voltage gradually increases in potential. That is, DS1 <DV1 <DSimn3 <DS3 <DV3 <DSimn5 <DS5 <DV5. As a result, the voltage dividing voltage input to the input terminals S1, V1, S3, V3, S5, and V5 can be gradually increased in this order regardless of the on / off state of the relay switches SN1, SP1, SN2, and SP2. can. In addition, in FIG. 10, each voltage dividing voltage is shown on the assumption that the applied voltage and the voltage between terminals are the same.

However, depending on the circuit tolerance and the amount of current, there is a possibility that each voltage dividing voltage will deviate. When this deviation becomes large, it becomes difficult to maintain the magnitude relationship of the input voltage dividing voltage. Therefore, in the monitoring IC50 of the first embodiment, as shown in FIG. 2, every other input channel into which the voltage dividing voltage is input is set. That is, between the voltage dividing voltage DS5 and the voltage dividing voltage DSmin5, between the voltage dividing voltage DSmin5 and the voltage dividing voltage DV3, between the voltage dividing voltage DS3 and the voltage dividing voltage DSmin3, and between the voltage dividing voltage DSmin3 and the voltage dividing voltage DV1. In order to provide a margin between the two, input channels CH2 and CH4 are assigned as read-through channels. As a result, even if each voltage dividing voltage deviates due to a circuit tolerance or the like, the magnitude relationship of the input voltage dividing voltage can be maintained, and the wraparound current can be reliably prevented.

(Second Embodiment)
The configuration of the first embodiment may be changed as in the following second embodiment. Hereinafter, in the second embodiment, differences from the configurations described in each of the above embodiments will be mainly described.

In the first embodiment, the second voltage dividing circuit 60 is configured to input the divided voltage DSmin3 and DSmin5 to the input terminals S3 and S5 via the diodes D1 and D2 when the applied voltage becomes 0V. Was there. However, the voltage actually input from the second voltage divider circuit 60 to the input terminals S3 and S5 is a predetermined value Vf (Vf) rather than the voltage divider voltages DSmin3 and DSmin5 due to the characteristics of the diodes D1 and D2 (forward voltage drop). Is known to drop by a certain value). Therefore, as shown in FIG. 11A, when the voltage between terminals becomes a predetermined value or less, DV1> DSmin3-Vf may occur. In this case, a wraparound current is generated and the detection accuracy deteriorates. There is a problem of doing.

Therefore, in the second embodiment, the configuration of the second voltage divider circuit is changed. Hereinafter, the second voltage dividing circuit 160 of the second embodiment will be described. As shown in FIG. 12, the connection point P21 between the resistor R41 and the resistor R51 is connected to the connection point P13 between the resistor R21 and the resistor R31 of the first voltage dividing circuit 40 via the switch SD1 as a switching unit. It is connected. At the same time, the connection point P21 is connected to the non-inverting input terminal side of the comparator CP1 as a comparison unit.

Further, the second voltage dividing circuit 160 includes a series connection body of the resistor R71 and the resistance R72, and one end of the series connection body is closer to the system 21 than the relay switch SP1 in the positive electrode side power supply path 23a of the system 21. The other end is connected to the negative electrode side power supply path 11b of the assembled battery 10. The inverting input terminal side of the comparator CP1 is connected to the connection point P31 between the resistor R71 and the resistor R72. That is, on the inverting input terminal side of the comparator CP1, the voltage dividing voltage DP1 obtained by dividing the applied voltage between the positive electrode side power supply path 23a and the negative electrode side power supply path 11b by the ninth voltage dividing ratio (R72 / (R71 + R72)). Is to be entered. The ninth voltage division ratio is set to be slightly larger than the seventh voltage division ratio.

Then, the comparator CP1 is configured to turn on the switch SD1 when the input voltage dividing voltage DSmin3 and the voltage dividing voltage DP1 are compared and it is determined that the voltage dividing voltage DSmin3 is larger than the voltage dividing voltage DP1. ing. As described above, since the ninth voltage dividing ratio is set to be slightly larger than the seventh voltage dividing ratio, the relay switches SN1 and SP1 are turned on, and an applied voltage equivalent to the voltage between terminals is applied to the system 21. If so, the voltage dividing voltage DSmin3 <the voltage dividing voltage DP1.

On the other hand, when the relay switches SN1 and SP1 are turned off and the energization to the system 21 is cut off, the voltage dividing voltage DSmin3> the voltage dividing voltage DP1, and the comparator CP1 has a voltage dividing voltage DSmin3 that is higher than the voltage dividing voltage DP1. Is also large, and the switch SD1 is turned on. Then, when the switch SD1 is turned on, the voltage dividing voltage DSmin3 is input to the input terminal S3.

Further, as shown in FIG. 12, the connection point P22 between the resistor R42 and the resistor R52 is a connection point between the resistor R22 and the resistor R32 of the first voltage dividing circuit 40 via the switch SD2 as a switching unit. It is connected to P15. At the same time, the connection point P22 is connected to the non-inverting input terminal side of the comparator CP2 as a comparison unit.

Further, the second voltage dividing circuit 160 includes a series connection body of the resistor R73 and the resistor R74, and one end of the series connection body is closer to the system 22 than the relay switch SP2 in the positive electrode side power supply path 24a of the system 22. The other end is connected to the negative electrode side power supply path 11b of the assembled battery 10. The inverting input terminal side of the comparator CP2 is connected to the connection point P32 between the resistor R73 and the resistor R74. That is, on the inverting input terminal side of the comparator CP2, the voltage dividing voltage DP2 obtained by dividing the applied voltage between the positive electrode side power supply path 24a and the negative electrode side power supply path 11b by the tenth voltage dividing ratio (R74 / (R73 + R74)). Is to be entered. The tenth voltage division ratio is set to be slightly larger than the eighth voltage division ratio.

Then, the comparator CP2 is configured to turn on the switch SD2 when the input voltage dividing voltage DSmin5 and the voltage dividing voltage DP2 are compared and it is determined that the voltage dividing voltage DSmin5 is larger than the voltage dividing voltage DP2. ing.

Similar to the above, when the relay switches SN2 and SP2 are turned off and the energization to the system 22 is cut off, the voltage dividing voltage DSmin5> the voltage dividing voltage DP2, and the comparator CP2 turns on the switch SD2. Then, when the switch SD2 is turned on, the voltage dividing voltage DSmin5 is input to the input terminal S5.

According to the configuration of the second embodiment, the following effects can be obtained.

In the second voltage dividing circuit 160, there are systems 21 and 22 in which the energization with the assembled battery 10 is cut off based on the comparison between the voltage applied to each system 21 and 22 and the voltage between the terminals of the assembled battery 10. Judge whether or not. Specifically, the comparator CP1 compares the voltage dividing voltage DSmin3 with the voltage dividing voltage DP1, and when it is determined that the voltage dividing voltage DSmin3 is larger than the voltage dividing voltage DP1, the switch SD1 is turned on. The voltage dividing voltage DP1 is obtained by dividing the voltage between the positive electrode side power supply path 23a of the system 21 and the negative electrode side terminal 10b of the assembled battery 10 by the ninth voltage dividing ratio. Therefore, if the relay switches SN1 and SP1 are turned off, the voltage dividing voltage DP1 also becomes zero, so that the comparator CP1 turns on the switch SD1 and inputs the voltage dividing voltage DSmin3 to the input terminal S3.

As described above, as shown in FIG. 11B, when the relay switches SN1 and SP1 are turned on, the voltage dividing voltage DS3 by the first voltage dividing circuit 40 is input to the input terminal S3 and is always input terminal. It becomes higher than the voltage dividing voltage DV1 input to V1. On the other hand, when the relay switches SN1 and SP1 are turned off, the voltage dividing voltage DSmin3 is input to the input terminal S3. At this time, since the voltage dividing voltage DSmin3 is input to the input terminal S3 as it is without passing through the diode, the voltage dividing voltage DSmin3 input to the input terminal S3 is always from the voltage dividing voltage DV1 input to the input terminal V1. Will also be higher. As described above, the wraparound current can be prevented.

Similarly, the voltage dividing voltage DSmin5 can be input to the input terminal S5 without a voltage drop, and a wraparound current can be prevented.

(Third Embodiment)
The configuration of the second embodiment may be changed as in the following third embodiment. Hereinafter, in the second embodiment, differences from the configurations described in each of the above embodiments will be mainly described. In this third embodiment, the configuration of the second embodiment will be described as a basic configuration.

In the second embodiment, the comparators CP1 and CP2 input the divided voltage of each voltage between the positive electrode side power supply paths 23a and 24a and the negative electrode side terminal 10b of the assembled battery 10, and input the voltage dividing voltage to the systems 21 and 22. It was determined whether or not the energization was cut off. However, each voltage between the positive electrode side power supply paths 23a and 24a and the negative electrode side terminal 10b of the assembled battery 10 is about the same as the voltage between the terminals, and it is necessary to secure the withstand voltage of the resistors R71 to R74. Therefore, there is a risk that the resistors R71 to R74 will become large.

Therefore, as shown in FIG. 13, in the second voltage dividing circuit 260 of the third embodiment, the connection point P13 between the resistor R21 and the resistor R31 in the first voltage dividing circuit 40 is set to the non-inverting input terminal side of the comparator CP1. It is connected so that the voltage dividing voltage DS3 is input. As a result, the comparator CP1 compares the voltage dividing voltage DS3 with the voltage dividing voltage DSmin3, and if the voltage dividing voltage DSmin3 is larger, the switch SD1 is turned on and the voltage dividing voltage DSmin3 is input to the input terminal S3. It becomes.

Then, as described above, the third voltage dividing ratio of the first voltage dividing circuit 40 is larger than the seventh voltage dividing ratio of the second voltage dividing circuit 260. Therefore, when the relay switches SN1 and SP1 are turned on and a voltage similar to the voltage between terminals is applied to the system 21, it is determined that the voltage dividing voltage DSmin3 is smaller. On the other hand, when the relay switches SN1 and SP1 are turned off and the energization to the system 21 is cut off, it is determined that the voltage dividing voltage DSmin3 is larger, and the switch SD1 is turned on.

As described above, when the relay switches SN1 and SP1 are turned off, the voltage dividing voltage DSmin3 is input to the input terminal S3. At this time, since the voltage dividing voltage DSmin3 is input to the input terminal S3 as it is without passing through the diode, the voltage dividing voltage DSmin3 input to the input terminal S3 is always from the voltage dividing voltage DV1 input to the input terminal V1. Will also be higher. Therefore, the wraparound current can be prevented.

Similarly, the connection point P15 between the resistor R22 and the resistor R32 in the first voltage divider circuit 40 is connected to the non-inverting input terminal side of the comparator CP2 so that the voltage divider voltage DS5 is input. As a result, when the relay switches SN2 and SP2 are turned off, the voltage dividing voltage DSmin5 is input to the input terminal S5. At this time, since the voltage dividing voltage DSmin5 is input to the input terminal S3 as it is without passing through the diode, the voltage dividing voltage DSmin5 input to the input terminal S5 is always larger than the voltage dividing voltage input to the input terminal V3. It gets higher. Therefore, the wraparound current can be prevented.

(Modification example)
-In the third embodiment, the comparator CP1 turns on the switch SD1 when the voltage dividing voltage DSmin3 is larger. As another example of this, the comparator CP1 may turn on the switch SD1 when the voltage dividing voltage DSmin3 is larger than a predetermined threshold value with respect to the voltage dividing voltage DS3. That is, the comparator CP1 may be provided with a dead zone or hysteresis. As a result, even if the applied voltage of the system 21 is about the same as the voltage between terminals and the difference between the third voltage division ratio and the seventh voltage division ratio is small, the switch SD1 is frequently turned on and off (chattering). ) Can be prevented and noise can be suppressed. Further, the comparator CP2 may be configured in the same manner.

-In the above embodiment, the monitoring IC 50 does not have to detect the voltage between the terminals of the assembled battery 10.

-In the above embodiment, every other input channel for inputting the voltage dividing voltage (that is, detecting the voltage) is set. That is, the input channels CH1, CH3, and CH5 are set as input channels for voltage detection. As another example of this, the input channel for inputting the voltage dividing voltage (that is, detecting the voltage) may be continuously set. For example, as shown in FIG. 14, a voltage dividing voltage may be input to the input channels CH1 to CH3. This makes it possible to reduce the number of unused input channels.

-In the above embodiment, the number of systems that detect the applied voltage may be arbitrarily changed.

-In the above embodiment, the voltage between the terminals of the assembled battery 10 is detected in the input channel CH1, but the input channel for detecting the voltage between the terminals may be changed.

Although this disclosure has been described in accordance with the examples, it is understood that the disclosure is not limited to the examples and structures. The present disclosure also includes various modifications and modifications within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are also within the scope of the present disclosure.

Claims (8)

1. It is applied to a power supply system including a storage battery (10) and a plurality of systems (21, 22) connected in parallel to the storage battery and to which a voltage between terminals of the storage battery is applied, respectively. In the voltage detection device (30) that detects each applied voltage applied to the system,
   A first voltage divider circuit (40) that divides the applied voltage of each system at two different voltage divider ratios, and
   Input channels (CH3, CH5) are set for each of the systems, and based on the difference between the two voltage dividers input from the first voltage divider circuit via the input channel, the voltage dividers of the systems are said to be the same. A detection circuit (50) for detecting each applied voltage is provided.
   Each of the input channels has a pair of input terminals (S3, V3, S5, V5).
   The first voltage dividing circuit is a voltage detecting device that divides and outputs the applied voltage at a voltage dividing ratio that is stepwise different for each input terminal.
2. A second voltage dividing circuit (60) for dividing the voltage between the terminals of the storage battery is provided.
   The second voltage divider circuit divides the voltage between the terminals at stepwise different voltage divider ratios for each system, and the system switch units (SN1, SP1, SN2, SP2) cut off the energization with the storage battery. The voltage detection device according to claim 1, wherein when the system is present, the voltage dividing voltage is output to the input channel set for the system.
3. The pair of input terminals includes a high potential side input terminal (V3, V5) and a low potential side input terminal (S3, S5).
   The voltage dividing ratio of the voltage dividing voltage output to the input channel by the second voltage dividing circuit is larger than the voltage dividing ratio of the voltage dividing voltage input to the high potential side input terminal of the input channel by the first voltage dividing circuit. Compared to the voltage divider ratio that is one step larger than the voltage divider ratio and that is one step smaller than the voltage divider ratio of the voltage divider voltage input to the low potential side input terminal of the input channel in the first voltage divider circuit. The voltage detection device according to claim 2, which is largely set.
4. In the second voltage dividing circuit, based on the comparison between the voltage applied to each system and the voltage between the terminals, whether or not the system exists in which the energization with the storage battery is cut off by the system switch unit. The voltage detection device according to claim 2 or 3.
5. The second voltage divider circuit
   Whether or not the system in which the energization is cut off exists based on the comparison between the voltage divided voltage divided by the first voltage dividing circuit and the voltage divided voltage divided by the second voltage dividing circuit. Comparison units (CP1, CP2) that determine
   When it is determined by the comparison unit that the system whose energization is cut off exists, the voltage dividing voltage divided by the second voltage dividing circuit is output to the input channel instead of the first voltage dividing circuit. The voltage detection device according to claim 2 or 3, further comprising switching units (SD1, SD2).
6. In the comparison unit, when the voltage dividing voltage input from the second voltage dividing circuit is larger than the voltage dividing voltage input from the first voltage dividing circuit by a predetermined threshold value or more, the energization is cut off. The voltage detector according to claim 5, wherein the system is determined to exist.
7. The voltage detection device according to any one of claims 1 to 6, wherein the voltage division ratio in the first voltage dividing circuit is set in consideration of a voltage drop amount.
8. The first voltage divider circuit divides the voltage between the terminals by two different voltage dividing ratios.
   The detection circuit inputs two voltage dividing voltages from the first voltage dividing circuit via the input channel (CH1) set for the storage battery, and is based on the difference between the voltage dividing voltages. The voltage detection device according to any one of claims 1 to 7, which detects the voltage between terminals.

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