# US 9,434,261 B2 · Welded contactor checking systems and methods

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- Number: US 9,434,261 B2
- Document ID: US9434261B2
- Status: Granted
- Kind: B2
- Application number: 13/647,890
- Filed: 2012-10-09
- Published: 2013-04-18
- Granted: 2016-09-06
- Earliest claimed: 2011-10-17
- Assignees: Robert Bosch GmbH; Samsung SDI Co., Ltd.
- Applicants: Robert Bosch GmbH; Samsung SDI Co., Ltd.
- Inventors: Jacob R. Bemrich; Joshua M. Anzicek
- Web page: https://patentgrep.com/patent/US9434261B2

## 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 3/12: Recording operating variables {; Monitoring of operating variables}
- B60L 50/51: characterised by AC-motors
- B60L 50/61: by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
- B60L 53/14: Conductive energy transfer
- B60L 58/12: responding to state of charge [SoC]
- B60L 58/21: having the same nominal voltage
- B60L 58/26: by cooling
- B60L 58/27: by heating
- G01R 31/3278: {of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002)}
- H01H 47/002: {Monitoring or fail-safe circuits}
- B60L 2220/42: with use of more than one motor
- B60L 2240/545: Temperature
- B60L 2240/547: Voltage
- B60L 2240/549: Current
- B60L 2240/80: Time limits
- B60L 2250/10: by alarm
- B60L 2250/16: by display
- 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 90/14: Plug-in electric vehicles
- 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
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A system includes a plurality of batteries, first and second relays, a relay control module, and a welding indication module. The batteries are electrically connected and collectively output power for an electric motor via first and second nodes. The first relay is connected between a first output of the batteries and the first node. The second relay is connected between a second output of the batteries and the second node. The relay control module controls the first and second relays. The welding indication module commands the relay control module to open the first relay during a diagnosis period, commands the relay control module to close the second relay during the diagnosis period, and indicates whether the first relay is welded closed based on a voltage between the first and second nodes during the diagnosis period.

## Claims

### Claim 1

A system of a vehicle, comprising:
a plurality of batteries that are electrically connected and that collectively output power for an electric motor via first and second nodes;
a first relay that is connected between a first output of the batteries and the first node;
a second relay that is connected between a second output of the batteries and the second node;
a third relay that is connected between the first output of the batteries and the first node; and
a battery control module comprising:
a relay control module operatively connected to the first and second relays and configured to open and close the first and second relays; and
a welding indication module operatively connected to the relay control module and configured to (i) command the relay control module to open the first relay during a first diagnosis period, (ii) command the relay control module to close the second relay during the first diagnosis period, (iii) measure a first voltage difference between a voltage at the first node and a voltage at the second node during the first diagnosis period, the first voltage difference being measured while the first relay is commanded open by the relay control module and the second relay is commanded closed by the relay control module, and (iv) output whether the first relay is welded closed based on the measured first voltage difference during the first diagnosis period,
wherein the welding indication module is further configured to (i) command the relay control module to open the first relay during a second diagnosis period, (ii) command the relay control module to close the third relay during the second diagnosis period, (iii) command the relay control module to open the second relay during the second diagnosis period, (iv) measure a second voltage difference between a voltage at the first node and a voltage at the second node during the second diagnosis period, the second voltage difference being measured while the first relay is commanded open by the relay control module, the second relay is commanded open by the relay control module, and the third relay is commanded closed by the relay control module, and (v) output whether the second relay is welded closed in response to the measured second voltage difference during the second diagnosis period.

### Claim 2 (depends on 1)

The system of claim 1 wherein the welding indication module is configured to output whether the first relay is welded closed in response to a change in the first voltage difference during the first diagnosis period.

### Claim 3 (depends on 1)

The system of claim 1 wherein the welding indication module configured to output whether the first relay is welded closed in response to a comparison of the first voltage difference and a third voltage difference measured between a voltage at the first output of the batteries and a voltage at the second output of the batteries during the first diagnosis period, the third voltage difference being measured while the first relay is commanded open by the relay control module and the second relay is commanded closed by the relay control module.

### Claim 4 (depends on 3)

The system of claim 3 wherein the welding indication module is configured to:
selectively output that the first relay is welded closed when the first voltage difference remains greater than a predetermined percentage of the third voltage difference; and
output that the first relay is not welded closed when the first voltage difference is less than the predetermined percentage of the third voltage difference.

### Claim 5 (depends on 3)

The system of claim 3 wherein the welding indication module is configured to:
output that the first relay is welded closed when the first voltage difference remains greater than first and second predetermined percentages of the third voltage difference during first and second predetermined periods, respectively; and
output that the first relay is not welded closed when at least one of:
the first voltage difference is less than the first predetermined percentage of the third voltage difference during the first predetermined period; and
the first voltage difference is less than the second predetermined percentage of the third voltage difference during the second predetermined period.

### Claim 6 (depends on 1)

The system of claim 1 wherein the welding indication module is configured to output whether the second relay is welded closed in response to a comparison of the second voltage difference and a fourth voltage difference measured between a voltage at the first output of the batteries and a voltage at the second output of the batteries during the second diagnosis period, the fourth voltage difference being measured while the first relay is commanded open by the relay control module, the second relay is commanded open by the relay control module, and the third relay is commanded closed by the relay control module.

### Claim 7 (depends on 6)

The system of claim 6 wherein the welding indication module is configured to:
output that the second relay is welded closed when the second voltage difference is greater than a second predetermined percentage of the fourth voltage difference; and
output that the second relay is not welded closed when the second voltage difference remains less than the second predetermined percentage of the fourth voltage difference.

### Claim 8 (depends on 1)

The system of claim 1 wherein the welding indication module is configured to illuminate a malfunction indicator lamp (MIL) when at least one of the first relay and the second relay is welded closed.

### Claim 9

A method comprising:
providing a plurality of batteries that are electrically connected and that collectively output power for an electric motor via first and second nodes;
providing a first relay that is connected between a first output of the batteries and the first node;
providing a second relay that is connected between a second output of the batteries and the second node;
providing a third relay that is connected between the first output of the batteries and the first node;
controlling the first relay and the second relay;
commanding opening of the first relay during a first diagnosis period;
commanding closing of the second relay during the first diagnosis period;
measuring a first voltage difference between a voltage at the first node and a voltage at the second node during the first diagnosis period, the first voltage difference being measured while the first relay is commanded open by the relay control module and the second relay is commanded closed by the relay control module;
outputting whether the first relay is welded closed based on the measured first voltage difference during the first diagnosis period;
commanding opening of the first relay during a second diagnosis period;
commanding closing of the third relay during the second diagnosis period;
commanding opening of the second relay during the second diagnosis period;
measure a second voltage difference between a voltage at the first node and a voltage at the second node during the second diagnosis period, the second voltage difference being measured while the first relay is commanded open by the relay control module, the second relay is commanded open by the relay control module, and the third relay is commanded closed by the relay control module; and
outputting whether the second relay is welded closed in response to the measured second voltage difference during the second diagnosis period.

### Claim 10 (depends on 9)

The method of claim 9 further comprising outputting whether the first relay is welded closed in response to a change in the first voltage difference during the first diagnosis period.

### Claim 11 (depends on 9)

The method of claim 9 further comprising outputting whether the first relay is welded closed in response to a comparison of the first voltage difference and a third voltage difference measured between a voltage at the first output of the batteries and a voltage at the second output of the batteries during the first diagnosis period, the third voltage difference being measured while the first relay is commanded open by the relay control module and the second relay is commanded closed by the relay control module.

### Claim 12 (depends on 11)

The method of claim 11 further comprising:
selectively outputting that the first relay is welded closed when the first voltage difference remains greater than a predetermined percentage of the third voltage difference; and
outputting that the first relay is not welded closed when the first voltage difference is less than the predetermined percentage of the third voltage difference.

### Claim 13 (depends on 11)

The method of claim 11 further comprising:
outputting that the first relay is welded closed when the first voltage difference remains greater than first and second predetermined percentages of the third voltage difference during first and second predetermined periods, respectively; and
outputting that the first relay is not welded closed when at least one of:
the first voltage difference is less than the first predetermined percentage of the third voltage difference during the first predetermined period; and
the first voltage difference is less than the second predetermined percentage of the third voltage difference during the second predetermined period.

### Claim 14 (depends on 9)

The method of claim 9 further comprising outputting whether the second relay is welded closed in response to a comparison of the second voltage difference and a fourth voltage difference measured between a voltage at the first output of the batteries and a voltage at the second output of the batteries during the second diagnosis period, the fourth voltage difference being measured while the first relay is commanded open by the relay control module, the second relay is commanded open by the relay control module, and the third relay is commanded closed by the relay control module.

### Claim 15 (depends on 14)

The method of claim 14 further comprising:
outputting that the second relay is welded closed when the second voltage difference is greater than a second predetermined percentage of the fourth voltage difference; and
outputting that the second relay is not welded closed when the second voltage difference remains less than the second predetermined percentage of the fourth voltage difference.

### Claim 16

A system comprising:
a plurality of batteries that are electrically connected and that collectively output power for a load via first and second nodes;
a first relay that is connected between a first output of the batteries and the first node;
a second relay that is connected between a second output of the batteries and the second node;
a third relay that is connected between the first output of the batteries and the first node; and
a battery control module comprising:
a relay control module operatively connected to the first and second relays and configured to open and close the first and second relays; and
a welding indication module operatively connected to the relay control module and configured to (i) command the relay control module to open the first relay during a diagnosis period, (ii) command the relay control module to close the second relay during the diagnosis period, (iii) measure a first voltage difference between a voltage at the first node and a voltage at the second node during the diagnosis period, the first voltage difference being measured while the first relay is commanded open by the relay control module and the second relay is commanded closed by the relay control module, and (iv) output whether the first relay is welded closed based on the measured first voltage difference during the diagnosis period,
wherein the welding indication module is further configured to (i) command the relay control module to open the first relay during a second diagnosis period, (ii) command the relay control module to close the third relay during the second diagnosis period, (iii) command the relay control module to open the second relay during the second diagnosis period, (iv) measure a second voltage difference between a voltage at the first node and a voltage at the second node during the second diagnosis period, the second voltage difference being measured while the first relay is commanded open by the relay control module, the second relay is commanded open by the relay control module, and the third relay is commanded closed by the relay control module, and (v) output whether the second relay is welded closed in response to the measured second voltage difference during the second diagnosis period.