# US 2014/0197841 A1 · Voltage monitoring apparatus

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- Number: US 2014/0197841 A1
- Document ID: US20140197841A1
- Status: Published application
- Kind: A1
- Application number: 14/156,930
- Filed: 2014-01-16
- Published: 2014-07-17
- Earliest claimed: 2013-01-16
- Assignees: Denso Corporation
- Applicants: Denso Corporation
- Inventors: Tomomichi MIZOGUCHI
- Web page: https://patentgrep.com/patent/US20140197841A1

## CPC

- G01R 31/396: Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
- B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors}
- B60L 58/10: for monitoring or controlling batteries
- B60L 58/18: of two or more battery modules
- B60L 2240/547: Voltage
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

In a voltage monitoring apparatus, a capacitor circuit includes at least one capacitor. Input-side switches are connected to electrode terminals of at least one battery cell, and apply voltage to terminals of the capacitor. A voltage detection circuit includes a pair of voltage sensing terminals connected to terminals of the capacitor, and detects the potential difference across voltage sensing terminals. Output-side switches are connected to terminals of the capacitor, and apply voltage across terminals of the capacitor to the voltage sensing terminals. An impedance circuit is connected to the voltage sensing terminals. A stabilizing power circuit is connected to the voltage sensing terminals via the impedance circuit, and stabilizes voltage of the voltage sensing terminals. Based on the detected voltage when one of the output-side switches is turned on, an on-failure of the remaining output-side switches which should not be turned on are detected by a control unit.

## Claims

### Claim 1

A voltage monitoring apparatus comprising:
a capacitor circuit including at least one capacitor;
an input-side switch group that includes a plurality of input-side switches connected to at least one pair of electrode terminals of at least one battery cell, the input-side switch group applying voltage to a pair of terminals of the at least one capacitor;
a voltage detection circuit that includes at least one pair of voltage sensing terminals connected to each of the terminals of the at least one capacitor, the voltage detection circuit detecting a potential difference across the at least one pair of voltage sensing terminals;
an output-side switch group that includes a plurality of output-side switches connected to the terminals of the at least one capacitor, the output-side switch group applying voltage across the terminals of the at least one capacitor to the at least one pair of voltage sensing terminals;
switch control means for controlling each of the plurality of input-side switches and each of the plurality of output-side switches;
failure detecting means for detecting, on the basis of the voltage detected by the voltage detection circuit when one of the output-side switches is turned on, an on-failure of at least one of the remaining output-side switches which should not be turned on;
an impedance circuit that is connected to each of the at least one pair of voltage sensing terminals; and
a stabilizing power circuit that is connected to each of the at least one pair of voltage sensing terminals via the impedance circuit and stabilizes voltage of each of the at least one pair of voltage sensing terminals.

### Claim 2 (depends on 1)

The voltage monitoring apparatus according to claim 1, wherein:
the voltage detection circuit includes a differential amplifier circuit that amplifies and outputs at least one potential difference between the at least one pair of voltage sensing terminals;
the differential amplifier circuit includes at least one pair of input resistors connected to the at least one pair of voltage sensing terminals; and
the stabilizing power circuit is connected to each of the at least one pair of voltage sensing terminals via the at least one pair of input resistors.

### Claim 3 (depends on 2)

The voltage monitoring apparatus according to claim 2, wherein:
the stabilizing power circuit is connected to the at least one pair of voltage sensing terminals and is connected to one input terminal of the differential amplifier circuit such that a predetermined offset voltage is added to an output signal of the differential amplifier circuit.

### Claim 4 (depends on 1)

The voltage monitoring apparatus according to claim 1, wherein:
the voltage detection circuit includes a differential amplifier circuit that amplifies and outputs a potential difference between the at least one pair of voltage sensing terminals;
the stabilizing power circuit is connected to the at least one pair of voltage sensing terminals and is connected to one input terminal of the differential amplifier circuit so as to add a predetermined offset voltage to an output signal of the differential amplifier circuit.

### Claim 5 (depends on 1)

The voltage monitoring apparatus according to claim 1, wherein:
the impedance circuit is configured such that a time constant of a circuit configured by the impedance circuit and the at least one capacitor becomes longer than a required detection time that is taken from when a voltage across the terminals of the at least one capacitor is applied to the at least one pair of voltage sensing terminals until when the a potential difference between the at least one pair of voltage sensing terminals is detected by the voltage detection circuit.

### Claim 6 (depends on 1)

The voltage monitoring apparatus according to claim 1, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 7 (depends on 2)

The voltage monitoring apparatus according to claim 2, wherein:
the impedance circuit is configured such that a time constant of a circuit configured by the impedance circuit and the at least one capacitor becomes longer than a required detection time that is taken from when a voltage across the terminals of the at least one capacitor is applied to the at least one pair of voltage sensing terminals until when the a potential difference between the at least one pair of voltage sensing terminals is detected by the voltage detection circuit.

### Claim 8 (depends on 2)

The voltage monitoring apparatus according to claim 2, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group that includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 9 (depends on 3)

The voltage monitoring apparatus according to claim 3, wherein:
the impedance circuit is configured such that a time constant of a circuit configured by the impedance circuit and the at least one capacitor becomes longer than a required detection time that is taken from when a voltage across the terminals of the at least one capacitor is applied to the at least one pair of voltage sensing terminals until when the a potential difference between the at least one pair of voltage sensing terminals is detected by the voltage detection circuit.

### Claim 10 (depends on 3)

The voltage monitoring apparatus according to claim 3, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 11 (depends on 4)

The voltage monitoring apparatus according to claim 4, wherein:
the impedance circuit is configured such that a time constant of a circuit configured by the impedance circuit and the at least one capacitor becomes longer than a required detection time that is taken from when a voltage across the terminals of the at least one capacitor is applied to the at least one pair of voltage sensing terminals until when the a potential difference between the at least one pair of voltage sensing terminals is detected by the voltage detection circuit.

### Claim 12 (depends on 4)

The voltage monitoring apparatus according to claim 4, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 13 (depends on 5)

The voltage monitoring apparatus according to claim 5, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 14 (depends on 9)

The voltage monitoring apparatus according to claim 9, wherein:
the capacitor circuit is configured by a serial connection of two capacitors that are connected in series to each other;
the output-side switch group includes a first output-side switch, a second output-side switch, and a third output-side switch, the first output-side switch and the second output-side switch being connected to a pair of ends of the serial connection of the two capacitors, the third output-side switch being connected to a connection portion between the two capacitors;
the voltage detection circuit includes a first voltage detection circuit and a second voltage detection circuit, the first voltage detection circuit being connected to the second output-side switch and the third output-side switch, the second voltage detection circuit being connected to the first output-side switch and the third output-side switch;
the failure detecting means is configured to:
(i) detect an on-failure of each of the first output-side switch and the second output-side switch on the basis of the detected voltage of each of the first voltage detection circuit and the second voltage detection circuit when the third output-side switch is turned on by the switch control means; and
(ii) detect an on-failure of the third output-side switch on the basis of; (a) the detected voltage of the first voltage detection circuit when the second output-side switch is turned on by the switch control means; or (b) the detected voltage of the second voltage detection circuit when the second output-side switch is turned on by the switch control means.

### Claim 15 (depends on 1)

The voltage monitoring apparatus according to claim 1, wherein
the at least one battery cell is a plurality of battery cells configuring a battery pack which is installed in a vehicle.

### Claim 16

A battery system comprising:
a battery pack that is configured by at least one battery cell; and
a voltage monitoring apparatus that includes:
a capacitor circuit including at least one capacitor;
an input-side switch group that includes a plurality of input-side switches connected to at least one pair of electrode terminals of at least one battery cell, the input-side switch group applying voltage to a pair of terminals of the at least one capacitor;
a voltage detection circuit that includes at least one pair of voltage sensing terminals connected to each of the terminals of the at least one capacitor, the voltage detection circuit detecting a potential difference across the at least one pair of voltage sensing terminals;
an output-side switch group that includes a plurality of output-side switches connected to the terminals of the at least one capacitor, the output-side switch group applying voltage across the terminals of the at least one capacitor to the at least one pair of voltage sensing terminals;
switch control means for controlling each of the plurality of input-side switches and each of the plurality of output-side switches;
failure detecting means for detecting, on the basis of the voltage detected by the voltage detection circuit when one of the output-side switches is turned on, an on-failure of at least one of the remaining output-side switches which should not be turned on;
an impedance circuit that is connected to each of the at least one pair of voltage sensing terminals; and
a stabilizing power circuit that is connected to each of the at least one pair of voltage sensing terminals via the impedance circuit and stabilizes voltage of each of the at least one pair of voltage sensing terminals.