US 9,000,727 B2Granted

System and method for balancing charge within a battery pack

AssigneeMotiv Power Systems, Inc.

InventorsJim Castelaz, Jessica Riley, Vishal Parikh, Steven Diamond, Samuel Chang

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Abstract

A system for balancing charge within a battery pack with a plurality of cells connected in series, including a capacitor; a processor configured to select a combination of donor cells and receiver cells from the plurality of cells in one of the following two modes: (1) a first mode where the number of donor cells is equal to the number of receiver cells, and (2) a second mode where the number of donor cells is greater than the number of receiver cells; and a plurality of switches that electrically connect the capacitor to the donor cells to charge the capacitor, and that electrically connected the capacitor to the receiver cells to discharge the capacitor. The transfer of charge between cells in the plurality of cells through the capacitor balances the charge within the battery pack.

Claims17

Dependent claims

A system for balancing charge within a battery pack comprising:

a plurality of cells connected in series;
a capacitor;
a processor operable in:
(1) a first mode, wherein the processor selects a primary combination of donor and receiver cells, the primary combination comprising a first combination that comprises equal numbers of donor cells and receiver cells;
(2) a second mode, wherein the processor selects a primary combination of donor and receiver cells, the primary combination comprising a second combination that comprises more donor cells than receiver cells;
a plurality of switches controlled by the processor for transiently coupling the plurality of cells to the capacitor, the plurality of switches operable between:
a first configuration in response to selection of the first combination, wherein the switches simultaneously electrically connect the capacitor to the donor cells of the first combination;
a second configuration in response to selection of the first combination, wherein the switches simultaneously electrically connect the capacitor to the receiver cells of the first combination;
a third configuration in response to selection of the second combination, wherein the switches simultaneously electrically connect the capacitor to the donor cells of the second combination;
and
a fourth configuration in response to selection of the second combination, wherein the switches simultaneously electrically connect the capacitor to the receiver cells of the second combination;
wherein the processor is configured to assign a score to each of the first and second combinations based on a resulting charge transfer rate, a resulting charge transfer efficiency and a resulting charge balance of the battery pack that would result if charge from the donor cells of the combination is transferred to the receiver cells of the combination;
wherein the processor is configured to adjust the scores based on a usage scenario of the battery pack or a user preference;
and
wherein the processor is configured to select one of the first or second combinations based on the scores.

12 more elements

A method for balancing charge using a system comprising a battery pack having a plurality of series-connected cells, a capacitor, a plurality of switches to transiently couple the plurality of cells to the capacitor, and a processor coupled to the plurality of cells and the plurality of switches, the method comprising the steps of:

determining, by the processor, available combinations of donor cells and receiver cells from the plurality of cells;
assigning, by the processor, to each available combination of donor cells and receiver cells a score based on a resulting charge transfer rate, a resulting charge transfer efficiency and a resulting charge balance of the battery pack that would result if charge from the donor cells is transferred to the receiver cells of the combination;
adjusting, by the processor, the score for each available combination based on a usage scenario of the battery pack or a user preference;
selecting, by the processor, one of the available combinations of donor cells and receiver cells from the plurality of cells based on each of the scores, wherein selecting comprises selecting between:
(1) a first combination comprising an equal number of donor cells and receiver cells;
and
(2) a second combination comprising more donor cells than receiver cells;
charging a capacitor by simultaneously electrically connecting the capacitor to the donor cells of the selected combination;
and
discharging the capacitor by simultaneously electrically connecting the capacitor to the receiver cells of the selected combination.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/954,598Filed 30 Jul 2013 · continuation
Priority: 23 Mar 2009
Published: US 2014/0084870 A127 Mar 2014
Granted: 7 Apr 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

H02J 7/56
For charge balancing, e.g. equalisation of charge between batteries: active balancing, e.g. using capacitor-based, inductor-based or DC-DC converters
H02J 7/345
Parallel operation in networks using both storage and other DC sources, e.g. providing buffering: using capacitors as storage or buffering devices
G05B 13/00
Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance
Y02T 10/70
Other road transportation technologies with climate change mitigation effect: energy storage systems for electromobility, e.g. batteries

Family

Application61/210,847Us provisional application · filed 23 Mar 2009
Application12/730,174Parent of this continuation · filed 23 Mar 2010
US 2014/0084870 A1Pre-grant publication · published 27 Mar 2014
US 8,519,670 B2Parent of this continuation
US 2010/0237830 A1Published application
US 9,000,727 B2This patent

From the US filing history. Foreign family members aren’t listed.