# US 2014/0152259 A1 · Response to detection of an overcharge event in a series connected battery element

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- Number: US 2014/0152259 A1
- Document ID: US20140152259A1
- Status: Published application
- Kind: A1
- Application number: 13/690,203
- Filed: 2012-11-30
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Tesla Motors, Inc.
- Applicants: Tesla Motors, Inc.
- Inventors: Francisco LePort; Scott Ira Kohn
- Web page: https://patentgrep.com/patent/US20140152259A1

## CPC

- H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
- H02J 7/52: for charge balancing, e.g. equalisation of charge between batteries
- H02J 7/61: against overcharge
- H02J 7/63: against overdischarge
- Y02E 60/10: Energy storage using batteries
- 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

## Abstract

A system and method for identifying and responding to exceptional charge events of series-connected energy storage elements.

## Claims

### Claim 1

A microprocessor-implemented response system for an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:
a first charge imbalance detection system monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality, said first charge imbalance detection system initiating a reduction of said charge imbalance using a first response modality;
a second charge imbalance detection system monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality; and
a remediation system initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event.

### Claim 2 (depends on 1)

The microprocessor-implemented response system of claim 1 wherein said exceptional charge event includes an overcharge of a battery element during a charging event, wherein said first detection modality includes a measurement of a voltage level of each battery element of the plurality of battery elements establishing a plurality of voltage imbalances between individual ones of the plurality of battery elements, wherein said first response modality includes adjusting said voltage levels to reduce said plurality of voltage imbalances, and wherein said second detection modality includes a statistical evaluation of a parameter of each battery element.

### Claim 3 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said response includes a suspension of said charging event.

### Claim 4 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said response includes setting a service flag.

### Claim 5 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said response includes activating a visual indicator.

### Claim 6 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said response includes inhibiting any charging event until the energy storage system is serviced.

### Claim 7 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said exceptional charge event is associated with a particular one battery element having a particular charge storage capacity and wherein said response includes use of said first response modality to reduce a stored charge of said particular one battery element to a predetermined fraction of said particular charge storage capacity intentionally creating an imbalance.

### Claim 8 (depends on 7)

The microprocessor-implemented response system of claim 7 wherein predetermined fraction is in the range of 50%+/−10%.

### Claim 9 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said exceptional charge event is associated with a particular one battery element having a particular charge storage capacity and wherein said response includes use of a response modality similar in operation to said first response modality to directly reduce a stored charge of said particular one battery element responsive to an assumed stored charge and a predetermined impedance electrically communicated to said particular one battery element for a time calculated to reduce said assumed stored charge to a predetermined fraction of said particular charge storage capacity.

### Claim 10 (depends on 9)

The microprocessor-implemented response system of claim 9 wherein predetermined fraction is in the range of 50%+/−10%.

### Claim 11 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said exceptional charge event is associated with a particular one battery element having a particular charge target and wherein said response includes a reduction of said particular charge target.

### Claim 12 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said charging event includes an associated maximum charge target and wherein said response includes a reduction of said associated maximum charge target.

### Claim 13 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said response includes logging a set of data associated with said exceptional charge event.

### Claim 14 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein the energy storage system includes a thermal control system providing a temperature control of the plurality of battery elements responsive to a thermal profile and wherein said response includes a modification to said thermal profile actuating said thermal control system at an increased cooling capacity.

### Claim 15 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said exceptional charge event is associated with a particular one battery element having an associated gain factor used when charging said particular one battery element and wherein said response includes a reduction to said associated gain factor.

### Claim 16 (depends on 2)

The microprocessor-implemented response system of claim 2 wherein said exceptional charge event is associated with a particular one battery element having an associated voltage offset factor used when charging said particular one battery element and wherein said response includes a reduction to said associated voltage offset factor.

### Claim 17

A computer-implemented method to respond to an exceptional charge event in an energy storage system having a plurality of series-connected battery elements, comprising:
monitoring, using the microprocessor, the energy storage system for a charge imbalance using a first detection modality;
initiating a reduction of said charge imbalance using a first response modality;
monitoring, using the microprocessor, the energy storage system for an exceptional charge event of a particular one battery element of the plurality of battery elements using a second detection modality different from said first detection modality; and
initiating a response to said exceptional charge event using a second response modality different from said first response modality, said response decreasing a risk associated with said exceptional charge event.

### Claim 18 (depends on 17)

The method of claim 17 wherein said exceptional charge event is an overcharge of said particular one battery element.

### Claim 19 (depends on 18)

The method of claim 18 further comprising transferring energy to the plurality of series-connected battery elements from a charging station and wherein said response initiating step includes asserting a stop charging signal to said charging station and suspending said energy transferring.

### Claim 20 (depends on 19)

The method of claim 19 further comprising setting an overcharge status flag whenever said overcharge is detected and wherein said stop charging signal remains asserted as long as said overcharge status flag remains set.

### Claim 21 (depends on 18)

The method of claim 18 further comprising transferring energy to the plurality of series-connected battery elements from a charging station and wherein said response initiating step includes asserting a reduced charging signal to said charging station and limiting said energy transferring to prevent charging to 100% SOC.

### Claim 22 (depends on 21)

The method of claim 21 further comprising setting an overcharge status flag whenever said overcharge is detected and wherein said reduced charging signal remains asserted as long as said overcharge status flag remains set.

### Claim 23 (depends on 18)

The method of claim 18 wherein said response initiating step includes asserting a diagnostic trouble code when detecting said overcharge.

### Claim 24 (depends on 18)

The method of claim 18 wherein said response initiating step includes providing a visual indication of said overcharge.

### Claim 25 (depends on 18)

The method of claim 18 wherein said response initiating step includes bleeding energy from said particular one battery element.

### Claim 26 (depends on 25)

The method of claim 25 wherein said energy bleeding is not performed by said first response modality and includes assuming an SOC for said particular one battery element and selectively coupling a predetermined impedance to said particular one battery element to discharge energy from said particular one battery element at a rate responsive to said SOC until a calculated SOC responsive to said SOC and to said predetermined impedance reaches a predetermined SOC level.

### Claim 27 (depends on 18)

The method of claim 18 wherein said particular one battery element includes an SOC charge target wherein said response initiating step includes reducing said SOC charge target.

### Claim 28 (depends on 18)

The method of claim 18 wherein the plurality of battery elements each includes an SOC charge target wherein said response initiating step includes reducing said SOC charge target.

### Claim 29 (depends on 18)

The method of claim 18 wherein said particular one battery element includes an adjustment profile including one or more of voltage gain and voltage offset factors and wherein said response initiating step includes adjusting said adjustment profile.

### Claim 30 (depends on 18)

The method of claim 18 wherein the plurality of battery elements each includes an adjustment profile including one or more of voltage gain and voltage offset factors and wherein said response initiating step includes adjusting said adjustment profiles.

### Claim 31 (depends on 18)

The method of claim 18 transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements and wherein said response initiating step includes increasing said cooling operation to reduce a temperature of said particular one battery element.

### Claim 32 (depends on 18)

The method of claim 18 transferring coolant to the plurality of series-connected battery elements from a coolant system to effect a cooling operation of the plurality of series-connected battery elements using a set of predetermined thermal setpoints and wherein said response initiating step includes lowering one or more setpoints of said set of predetermined thermal setpoints to increase said cooling operation.