# US 11,307,256 B2 · Diagnostic apparatus and diagnostic method

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- Number: US 11,307,256 B2
- Document ID: US11307256B2
- Status: Granted
- Kind: B2
- Application number: 17/042,486
- Filed: 2019-03-19
- Published: 2021-01-28
- Granted: 2022-04-19
- Earliest claimed: 2018-04-02
- Assignees: Marelli Corporation
- Applicants: Marelli Corporation
- Inventors: Masanao Shimazaki; Yoshiyuki Kikuchi; Junya Tanaka
- Web page: https://patentgrep.com/patent/US11307256B2

## CPC

- G01R 31/52: Testing for short-circuits, leakage current or ground faults
- B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors}
- B60L 3/12: Recording operating variables {; Monitoring of operating variables}
- B60L 58/21: having the same nominal voltage
- 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 31/36: Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
- G01R 31/3646: {for indicating electrical conditions or variables, e.g. visual or audible indicators}
- G01R 31/3648: {comprising digital calculation means, e.g. for performing an algorithm}
- G01R 31/3835: involving only voltage measurements
- G01R 31/54: Testing for continuity
- G01R 31/64: Testing of capacitors
- H01M 10/06: Lead-acid accumulators (semi-lead accumulators H01M10/20)
- H01M 10/4264: {with capacitors}
- H01M 10/4285: {Testing apparatus}
- H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569)
- H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J 7/02: for charging batteries from AC mains by converters
- B60L 2240/547: Voltage
- H01M 2010/4271: {Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing}
- Y02E 60/10: Energy storage using batteries
- 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
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A diagnostic apparatus includes a capacitor capable of being connected in parallel with a first battery, first switches that switch the connection state between a plurality of the first batteries and the capacitor, a detection circuit, a second switch that switches the connection state between the capacitor and the detection circuit, a changeover switch that switches the connection state between a second battery and the capacitor, a controller, and a diagnostic unit. The controller turns on the changeover switch to apply a voltage to the capacitor from the second battery, the detection circuit subsequently detects a potential difference or a discharge current, and the diagnostic unit diagnoses at least one of the capacitor, a lowermost first switch, and the second switch.

## Claims

### Claim 1

A diagnostic apparatus comprising:
a capacitor capable of being connected in parallel with each first battery among a plurality of first batteries connected in series;
a plurality of first switches configured to switch a connection state between the plurality of first batteries and the capacitor;
a detection circuit configured to detect a potential difference between terminals of the capacitor or to detect a discharge current from the capacitor;
a second switch configured to switch a connection state between the capacitor and the detection circuit;
a changeover switch configured to switch a connection state between the capacitor and a second battery that differs from the first batteries;
a controller configured to control the plurality of first switches, the second switch, and the changeover switch; and
a diagnostic unit configured to diagnose at least one of the capacitor, a lowermost first switch among the plurality of first switches, and the second switch, the lowermost first switch being connected to ground;
wherein the detection circuit detects the potential difference or the discharge current after the controller turns on the changeover switch to apply a voltage to the capacitor from the second battery; and
wherein the diagnostic unit diagnoses at least one of the capacitor, the lowermost first switch, and the second switch.

### Claim 2 (depends on 1)

The diagnostic apparatus of claim 1, further comprising a constant voltage circuit capable of generating a constant voltage from the second battery and of outputting the constant voltage to the capacitor via the changeover switch.

### Claim 3 (depends on 2)

The diagnostic apparatus of claim 2, wherein the constant voltage is smaller than a maximum voltage suppliable by the plurality of first batteries connected in series.

### Claim 4 (depends on 2)

The diagnostic apparatus of claim 2, wherein the constant voltage is larger than a maximum voltage suppliable by each first battery.

### Claim 5 (depends on 1)

The diagnostic apparatus of claim 1, wherein the second battery is a lead-acid battery.

### Claim 6 (depends on 2)

The diagnostic apparatus of claim 2, wherein the controller is configured to diagnose whether the capacitor possibly has a short-circuit fault, whether the second switch possibly has an open fault, or whether an output of the detection circuit is possibly stuck at 0 V, based on the potential difference between the terminals of the capacitor detected by the detection circuit while the second switch is on after the controller outputs the constant voltage to the capacitor.

### Claim 7 (depends on 6)

The diagnostic apparatus of claim 6, wherein the controller is configured to diagnose whether the capacitor is possibly leaking based further on the potential difference between the terminals of the capacitor detected by the detection circuit after the controller turns the constant voltage off.

### Claim 8 (depends on 6)

The diagnostic apparatus of claim 6,
wherein the second switch comprises an upper second switch configured to switch a connection state between one end of the capacitor and the detection circuit and a lower second switch configured to switch a connection state between another end of the capacitor and ground; and
wherein the controller is configured to diagnose whether the upper second switch possibly has the short-circuit fault based further on the potential difference between the terminals of the capacitor detected by the detection circuit after the controller turns the constant voltage off and then turns the second switch off.

### Claim 9 (depends on 8)

The diagnostic apparatus of claim 8, wherein the controller is configured to diagnose whether the lower second switch possibly has a short-circuit fault or whether the lowermost first switch possibly has a short-circuit fault based on the potential difference between the terminals of the capacitor detected by the detection circuit after the controller outputs the constant voltage to the capacitor, subsequently turns the constant voltage off, and then turns the second switch on.

### Claim 10 (depends on 1)

The diagnostic apparatus of claim 1, wherein the controller is configured to diagnose whether an output of the detection circuit is possibly stuck at a power supply voltage based on the potential difference between the terminals of the capacitor detected by the detection circuit before the controller outputs a constant voltage to the capacitor while the second switch is off.

### Claim 11 (depends on 1)

The diagnostic apparatus of claim 1, wherein the controller is configured to diagnose whether the detection circuit possibly has a fault based on the potential difference between the terminals of the capacitor detected by the detection circuit while the second switch is on after the controller outputs a constant voltage to the capacitor.

### Claim 12

A diagnostic method in a diagnostic apparatus comprising a capacitor capable of being connected in parallel with each first battery among a plurality of first batteries connected in series, a plurality of first switches configured to switch a connection state between the plurality of first batteries and the capacitor, a detection circuit configured to detect a potential difference between both terminals of the capacitor or to detect a discharge current from the capacitor, a second switch configured to switch a connection state between the capacitor and the detection circuit, and a changeover switch configured to switch a connection state between the capacitor and a second battery that differs from the first batteries, the diagnostic method comprising:
detecting, using the detection circuit, the potential difference or the discharge current after the changeover switch is turned on to apply a voltage to the capacitor from the second battery; and
diagnosing at least one of the capacitor, a lowermost first switch among the plurality of first switches, and the second switch, the lowermost first switch being connected to ground.