# US 2014/0197683 A1 · Electric vehicle and insulation state determination method for electric vehicle

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- Number: US 2014/0197683 A1
- Document ID: US20140197683A1
- Status: Published application
- Kind: A1
- Application number: 14/153,274
- Filed: 2014-01-13
- Published: 2014-07-17
- Earliest claimed: 2013-01-15
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Inventors: Tsubasa Migita; Mitsuyori Matsumura
- Web page: https://patentgrep.com/patent/US20140197683A1

## CPC

- B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors}
- B60L 3/0069: {relating to the isolation, e.g. ground fault or leak current}
- B60L 3/04: Cutting off the power supply under fault conditions (protective devices and circuit arrangements in general H01H; H02H)
- B60L 15/007: {Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles}
- B60L 15/20: for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
- B60L 50/16: with provision for separate direct mechanical propulsion
- B60L 50/40: using propulsion power supplied by capacitors
- B60L 50/61: by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
- B60L 2210/14: Boost converters
- B60L 2210/40: DC to AC converters
- B60L 2220/14: Synchronous machines
- B60L 2240/12: Speed
- B60L 2240/421: Speed
- B60L 2240/423: Torque
- B60L 2240/547: Voltage
- B60L 2240/549: Current
- B60L 2260/26: Transition between different drive modes
- B60L 2270/20: Inrush current reduction, i.e. avoiding high currents when connecting the battery
- Y02T 10/62: Hybrid vehicles
- Y02T 10/64: Electric machine technologies in electromobility
- Y02T 10/70: Energy storage systems for electromobility, e.g. batteries
- Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
- Y02T 10/72: Electric energy management in electromobility
- 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

Provided is an electric vehicle including an electric system that generates drive power, a detector, and a controller. The electric system includes a power storage device, a drive device that uses power of the power storage device to generate drive power, a first relay provided between the positive electrode of the power storage device and the drive device, and a second relay provided between the negative electrode of the power storage device and the drive device. The detector is electrically connected to the power storage device and detects an insulation abnormality in the electric system. The controller determines the insulation state of the electric system on the basis of a detection result of the detector obtained when the first relay and the second relay are open and a detection result of the detector obtained when either of the first relay and the second relay is thereafter closed.

## Claims

### Claim 1

An electric vehicle comprising:
an electric system configured to generate drive power, the electric system comprising:
a power storage device;
a drive device configured to use power of the power storage device to generate drive power;
a first relay provided between a positive electrode of the power storage device and the drive device; and
a second relay provided between a negative electrode of the power storage device and the drive device;
a detector configured to detect an insulation abnormality in the electric system, the detector being electrically connected to the power storage device; and
a controller configured to determine an insulation state of the electric system on the basis of a detection result of the detector obtained when the first relay and the second relay are open and a detection result of the detector obtained when either of the first relay and the second relay is thereafter closed.

### Claim 2 (depends on 1)

The electric vehicle according to claim 1, wherein
the controller is configured to determine the insulation state of the electric system on the basis of the detection result of the detector obtained when the first relay and the second relay are open and the detection result of the detector obtained when the first relay is thereafter closed.

### Claim 3 (depends on 1)

The electric vehicle according to claim 1, wherein
the controller is configured to determine that the insulation state of the electric system is indefinite when opening of the first relay and the second relay changes a detection result of the detector from abnormal to normal and the detection result of the detector indicates a normal state even when either of the first relay and the second relay is thereafter closed.

### Claim 4 (depends on 1)

The electric vehicle according to claim 1, wherein
the controller is configured to determine that an insulation resistance of the drive device has decreased when opening of the first relay and the second relay changes a detection result of the detector from abnormal to normal and the detection result of the detector indicates an abnormal state as a result of either of the first relay and the second relay being thereafter closed.

### Claim 5 (depends on 1)

The electric vehicle according to claim 1, wherein
the controller is configured to determine that an insulation resistance of the power storage device has decreased when a detection result of the detector indicates an abnormal state when the first relay and the second relay are open.

### Claim 6 (depends on 1)

The electric vehicle according to claim 1, wherein
the detector comprises:
a resistor element;
an AC power source configured to generate an AC voltage having a predetermined frequency;
a capacity element electrically connected between the resistor element and the power storage device; and
a voltage detection unit configured to detect a voltage component having the predetermined frequency in the power line between the resistor element and the capacity element,
the AC power source being electrically connected between the resistor element and a vehicle ground.

### Claim 7

An insulation state determination method for an electric vehicle, comprising:
detecting with a detector an insulation abnormality of an electric system that generates drive power;
opening a first relay provided between a positive electrode of a power storage device and a drive device, and opening a second relay provided between a negative electrode of the power storage device and the drive device;
closing either of the first relay and the second relay after the first relay and the second relay have been opened; and
determining an insulation state of the electric system on the basis of a detection result of the detector obtained when the first relay and the second relay are open, and a detection result of the detector obtained when either of the first relay and the second relay is closed.

### Claim 8 (depends on 7)

The insulation state determination method according to claim 7, wherein
the insulation state of the electric system is determined on the basis of the detection result of the detector obtained when the first relay and the second relay are open and the detection result of the detector obtained when the first relay is closed.