# US 11,307,254 B2 · Contactor failure rate prediction system and method

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- Number: US 11,307,254 B2
- Document ID: US11307254B2
- Status: Granted
- Kind: B2
- Application number: 16/610,181
- Filed: 2018-09-28
- Published: 2020-02-20
- Granted: 2022-04-19
- Earliest claimed: 2017-09-29
- Assignees: LG Energy Solution, Ltd.
- Applicants: LG Chem, Ltd.
- Inventors: Hyunki Cho; Chang Hyun Sung; Sang Hoon Lee; Yean Sik Choi
- Web page: https://patentgrep.com/patent/US11307254B2

## CPC

- G01R 31/3274: {Details related to measuring, e.g. sensing, displaying or computing; Measuring of variables related to the contact pieces, e.g. wear, position or resistance (measuring contact resistance G01R27/205)}
- 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)}
- G01R 19/165: Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G05B 23/0283: {Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] (preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06)}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

A system of predicting a failure rate of a contactor before the generation of a failure by counting a lifespan index of the contactor based on normality of through-currents of a primary side and a secondary side of the contactor, and determining that a failure rate of the contactor increases when a count value for an abnormal through-current exceeds a predetermined threshold value.

## Claims

### Claim 1

A system for predicting a failure rate of a contactor connected to a battery, the system comprising:
an on/off detecting unit configured to detect an on/off operation of the contactor;
a lifespan index counting unit configured to count a lifespan index of the contactor based on whether an electric conducting state of the contactor corresponds to a predetermined electric conducting state during the on operation of the contactor; and
a failure rate predicting unit configured to predict a failure rate of the contactor based on the counted lifespan index,
wherein the lifespan index counting unit includes:
a first measuring unit, which measures control voltage values of primary-side upper and lower ends of the contactor;
a second measuring unit, which measures control current values of the primary-side tipper and lower ends of the contactor;
a third measuring unit, which measures an inrush current value of a secondary side of the contactor; and
a fourth measuring unit, which measures a through-current value flowing through the secondary side of the contactor.

### Claim 2 (depends on 1)

The system of claim 1, wherein the first measuring unit determines whether the control voltage values of the primary-side upper and lower ends of the contactor exceed a predetermined threshold value,
wherein the second measuring unit determines whether the control current values of the primary-side upper and lower ends of the contactor exceed a predetermined threshold value, wherein the third measuring unit determines whether the inrush current value of the secondary side of the contactor exceeds a predetermined threshold value, and
wherein the fourth measuring unit determines whether the through-current value of the secondary side of the contactor exceeds a predetermined threshold value.

### Claim 3 (depends on 2)

The system of claim 2, wherein when the measurement results of the first to fourth measuring units do not exceed the respective predetermined threshold values, the lifespan index counting unit determines that the electric conducting state for the contactor corresponds to the predetermined electric conducting state, and increases and counts a first lifespan index among the lifespan indexes of the contactor, and
when any one or more of the measurement results of the first to fourth measuring units exceed the respective predetermined threshold values, the lifespan index counting unit determines that the electric conducting state for the contactor does not correspond to the predetermined electric conducting state, and increases and counts a second lifespan index among the lifespan indexes of the contactor.

### Claim 4 (depends on 3)

The system of claim 3, wherein when a result value obtained by counting the second lifespan index of the contactor exceeds a predetermined threshold value, the failure rate predicting unit determines that a failure rate of the contactor increases.

### Claim 5 (depends on 1)

The system of claim 1, wherein the first to third measuring units respectively determine whether the control voltage values of the primary-side upper and lower ends of the contactor, the control current values of the primary-side upper and lower ends of the contactor, and the inrush current value of the secondary side of the contactor exceed the respective predetermined threshold values in the case where the contactor is on-operated, and
the fourth measuring unit determines whether the through-current value of the secondary side of the contactor exceeds the respective predetermined threshold value in the case where the contactor is off-operated.

### Claim 6

A method of predicting a failure rate of a contactor connected to a battery, the method comprising:
detecting, by an on/off detecting unit, an on/off operation of the contactor;
counting, by a lifespan index counting unit, a lifespan index of the contactor based on whether an electric conducting state for the contactor corresponds to a predetermined electric conducting state during an on-operation of the contactor; and
predicting, by a failure rate predicting unit, a failure rate of the contactor based on the counted lifespan index,
wherein the counting of the lifespan index of the contactor includes:
measuring, by a first measuring unit, control voltage values of primary-side upper and tower ends of the contactor;
measuring, by a second measuring unit, control current values of the primary-side upper and lower ends of the contactor;
measuring, by a third measuring unit, an inrush current value of a secondary side of the contactor; and
measuring, by a fourth measuring unit, a through-current value flowing through the secondary side of the contactor.

### Claim 7 (depends on 6)

The method of claim 6, wherein the counting of the lifespan index of the contactor further includes:
determining, by the first measuring unit, whether the control voltage values of the primary-side upper and lower ends of the contactor exceed a predetermined threshold value,
determining, by the second measuring unit, whether the control current values of the secondary-side upper and lower ends of the contactor exceed a predetermined threshold value,
determining, by the third measuring unit, whether the inrush current value of the secondary side of the contactor exceeds a predetermined threshold value, and
determining, by the fourth measuring unit, whether the through-current value of the secondary side of the contactor exceeds a predetermined threshold value.

### Claim 8 (depends on 7)

The method of claim 7, wherein the counting of the lifespan index of the contactor further includes: when the measurement results of the first to fourth measuring units do not exceed the predetermined threshold values, determining, by the lifespan index counting unit, that the electric conducting state for the contactor corresponds to the predetermined electric conducting state, and increasing and counting a first lifespan index among the lifespan indexes of the contactor, and
wherein when any one or more of the measurement results of the first to fourth measuring units exceed the predetermined threshold values, determining, by the lifespan index counting unit, that the electric conducting state for the contactor does not correspond to the predetermined electric conducting state, and increasing and counting a second lifespan index among the lifespan indexes of the contactor.

### Claim 9 (depends on 8)

The method of claim 8, wherein the predicting of the failure rate of the contactor includes when a result value obtained by counting the second lifespan index of the contactor exceeds a predetermined threshold value, determining, by the failure rate predicting unit, that a failure rate of the contactor increases.

### Claim 10 (depends on 6)

The method of claim 6, wherein the counting of the lifespan index of the contactor includes:
respectively determining, by the first to third measuring units, whether the control voltage values of the primary-side upper and lower ends of the contactor, the control current values of the primary-side upper and lower ends of the contactor, and the inrush current value of the secondary side of the contactor exceed the respective predetermined threshold values in the case where the contactor is on-operated, and
determining, by the fourth measuring unit, whether the through-current value of the secondary side of the contactor exceeds the predetermined threshold value in the case where the contactor is off-operated.