Abstract: An electrode heat treatment device and associated method for fabricating an electrode are described, and include forming a workpiece, including coating a current collector with a slurry. The workpiece is placed on a first spool, and the first spool including the workpiece is placed in a sealable chamber, wherein the sealable chamber includes the first spool, a heat exchange work space, and a second spool. An inert environment is created in the sealable chamber. The workpiece is subjected to a multi-step continuous heat treatment operation in the inert environment, wherein the multi-step continuous heat treatment operation includes continuously transferring the workpiece through the heat exchange work space between the first spool and the second spool and controlling the heat exchange work space to an elevated temperature.

Abstract: A battery control system for a vehicle includes a battery state estimator configured to obtain a battery cell open circuit voltage (OCV) of a battery in response to a charging system charging the battery to a maximum charging voltage. The system includes a negative voltage determination module configured to determine a negative OCV of the battery based on the obtained cell or battery OCV. The system includes a voltage shift determination module configured to identify a difference between the negative OCV of the battery and a previous negative OCV of the battery. The system also includes a charge voltage module configured to selectively reduce the maximum charging voltage to a reduced maximum charging voltage based on the difference and transmit the reduced maximum charging voltage to the charging system. The charging system is instructed to charge the battery such that the battery does not exceed the reduced maximum charging voltage.

Abstract: In an embodiment, an electrode comprises a current collector and an active layer located on at least one side of the current collector and in electrical communication with the current collector. The active layer comprises a binder and an expanded silicon; wherein the active layer expands by less than or equal to 10 volume percent when in use. In another embodiment, a method of forming an electrode comprises forming the electrode from a pre-cycled, expanded silicon.

Abstract: A method of forming an electrode includes attaching a tab to a collector to form a pre-tabbed current collector; disposing the pre-tabbed current collector onto a non-stick substrate to form a workpiece; and casting a slurry onto the workpiece to form a film. The slurry includes an active material component, one or more carbon additives, and at least one of a filamentary copper additive and a dendritic copper additive. The method includes drying the film at a first temperature to form a dried film; curing the dried film under pressure at a second higher temperature to form a cured film; removing the cured film from the non-stick substrate to form a precursor film; and carbonizing and annealing the precursor film at a third higher temperature. Carbonizing forms a three-dimensional electrically-conductive network and annealing forms a second contiguous network of copper connected to the active material component to form the electrode.

Abstract: Methods for fabricating electrodes include coating a current collector with a slurry and pyrolyzing the coated current collector to produce the electrode with a layer of silicon-based host material. The slurry can include one or more solvents and a dry fraction having silicon particles, one or more polymeric binders, and carbon fibers. Pyrolyzing includes heating at a first temperature, and subsequently heating at a second temperature higher than the first temperature. The silicon particles include single-phase silicon and/or Li2Si, have an average particle diameter of less than 10 ?m, and can be 70% of the dry fraction. The polymeric binders can be only polyacrylonitrile, or optionally one or more fluorinated polymers. The carbon fibers have an average diameter of at least about 50 nm, an average length of at least about 1 ?m, and can be up to 15 wt. % of the dry fraction.

Abstract: Methods of scavenging acid in a lithium-ion electrochemical cell are provided. An electrolyte solution that contains an acid or is capable of forming the acid is contacted with a polymer comprising a nitrogen-containing acid-trapping moiety selected from the group consisting of: an amine group, a pyridine group, and combinations thereof. The nitrogen-containing acid-trapping moiety scavenges acidic species present in the electrolyte solution by participating in a Lewis acid-base neutralization reaction. The electrolyte solution comprises a lithium salt and one or more solvents and is contained in the electrochemical cell that further comprises a first electrode, a second electrode having an opposite polarity from the first electrode, and a porous separator. Lithium ions can be cycled through the separator and electrolyte solution from the first electrode to the second electrode, where acid generated during the cycling is scavenged by the polymer comprising a nitrogen-containing acid-trapping moiety.

Abstract: A battery control system for a vehicle includes a battery state estimator configured to obtain a battery cell open circuit voltage (OCV) of a battery in response to a charging system charging the battery to a maximum charging voltage. The system includes a negative voltage determination module configured to determine a negative OCV of the battery based on the obtained cell or battery OCV. The system includes a voltage shift determination module configured to identify a difference between the negative OCV of the battery and a previous negative OCV of the battery. The system also includes a charge voltage module configured to selectively reduce the maximum charging voltage to a reduced maximum charging voltage based on the difference and transmit the reduced maximum charging voltage to the charging system. The charging system is instructed to charge the battery such that the battery does not exceed the reduced maximum charging voltage.

Abstract: A method of forming an electrode includes attaching a tab to a collector to form a pre-tabbed current collector; disposing the pre-tabbed current collector onto a non-stick substrate to form a workpiece; and casting a slurry onto the workpiece to form a film. The slurry includes an active material component, one or more carbon additives, and at least one of a filamentary copper additive and a dendritic copper additive. The method includes drying the film at a first temperature to form a dried film; curing the dried film under pressure at a second higher temperature to form a cured film; removing the cured film from the non-stick substrate to form a precursor film; and carbonizing and annealing the precursor film at a third higher temperature. Carbonizing forms a three-dimensional electrically-conductive network and annealing forms a second contiguous network of copper connected to the active material component to form the electrode.

Abstract: During the charging of lithium-ion batteries, comprising graphite anode particles, the goal is to intercalate lithium into the anode materials as LiC6. But it is possible to conduct the charging process at a rate that lithium is undesirably plated, undetected, as lithium metal on the particles of graphite. During an open-circuit period of battery operation, immediately following such a charging period, the presence of lithium plating can be detected, using a computer-based monitoring system, by continually measuring the cell potential (Vcell) over a brief period of open-circuit time, fitting the open-circuit voltage data to a best cubic polynomial fit, and then determining dVcell/dt (mV/s) from the polynomial fit over a like period of time. It is found that the presence of a maximum or a minimum in the derivative curve (a local minimum) reliably correlates with plated lithium on the graphite particles of the anode.

Abstract: A discharge module is configured to determine a change in capacity of the battery between: (i) a measurement of a first open circuit voltage (OCV) of a battery of a vehicle; and (ii) a measurement of a second OCV of the battery. A lookup table is stored in memory and includes reference states of charge (SOCs) indexed by reference OCVs and reference capacities. A relationship module is configured to: from the lookup table, identify a first set of the reference SOCs associated with the first OCV and the reference capacities, respectively; from the lookup table, identify a second set of the reference SOCs associated with the second OCV and the reference capacities, respectively; determine changes in SOC associated with the reference capacities; determine changes in capacity; and determine an equation that relates changes in capacity to capacity based on the changes in capacity and the reference capacities, respectively.

Abstract: Evaluation of a DC power source can include communication with a voltmeter that is arranged to monitor electrical potential across positive and negative electrodes. The method includes determining a full-cell open-circuit voltage (“OCV”), an associated positive half-cell OCV, and an associated negative half-cell OCV at a start-of-life point of the DC power source. A lithium balance model is executed to determine a plurality of beginning states associated with an electrode alignment of the DC power source. An in-use state for the full-cell OCV is determined. An optimization routine is executed employing the lithium balance model to determine in-use states associated with the electrode alignment of the DC power source based upon the in-use state for the full-cell OCV and the beginning states associated with electrode alignment. A negative-to-positive (“N/P”) ratio is determined based upon the in-use states, and battery life is evaluated based upon the N/P ratio.

Abstract: A lithium ion battery has a positive electrode or cathode having a silicon modified mixed metal oxide including a compound having empirical formula Li[LiyMna-xSixMIIIbMIIc]O2??(I) wherein y=0.01-0.33; x=0.001-0.15; a, b, and c are each greater than zero; MIII is a trivalent metal or a combination of metals with an average valence of +3; MII is a divalent metal or a combination of metals with an average valence of +2; and y+4a+3b+2c is equal to 3 or about 3. Such a silicon modified mixed metal oxide may be exemplified by formula: Li [Li0.2 Mn0.49 Si0.05 Ni0.13 Co0.13]O2.

Abstract: A hybrid negative electrode having high energy capacity and high power capacity used in an electrochemical cell for lithium-ion electrochemical batteries is provided. The electrode may include about 40% to about 60% by mass of a high energy capacity electroactive material having a specific capacity of greater than or equal to about 310 mAh/g and about 40% to about 60% by mass of a high power capacity electroactive material having a potential versus Li/Li+ of greater than or equal to about 1 V during lithium ion insertion. The hybrid negative electrode is capable of a charge rate of greater than or equal to about 4 C at 25° C. In other variations, an electrochemical cell is provided that includes a first negative electrode with a high energy capacity electroactive material and a second negative electrode with a high power capacity electroactive material.

Abstract: System and methods for estimating a relationship between a SOC and an OCV of a battery system included in a vehicle are presented. In certain embodiments, an initial relationship between an open circuit voltage (“OCV”) and a state of charge (“SOC”) of a cell of the battery system may be determined at a beginning of life of the cell. Changes in one or more stoichiometric points of a half-cell of the cell may be determined as the cell ages. Based on the determined stoichiometric point changes of the half-cell, an initial relationship between the OCV and the SOC of the cell may be adjusted to generate an updated relationship between the OCV and the SOC of the cell.

Abstract: Methods of scavenging acid in a lithium-ion electrochemical cell are provided. An electrolyte solution that contains an acid or is capable of forming the acid is contacted with a polymer comprising a nitrogen-containing acid-trapping moiety selected from the group consisting of: an amine group, a pyridine group, and combinations thereof. The nitrogen-containing acid-trapping moiety scavenges acidic species present in the electrolyte solution by participating in a Lewis acid-base neutralization reaction. The electrolyte solution comprises a lithium salt and one or more solvents and is contained in the electrochemical cell that further comprises a first electrode, a second electrode having an opposite polarity from the first electrode, and a porous separator. Lithium ions can be cycled through the separator and electrolyte solution from the first electrode to the second electrode, where acid generated during the cycling is scavenged by the polymer comprising a nitrogen-containing acid-trapping moiety.

Abstract: Evaluation of a DC power source can include communication with a voltmeter that is arranged to monitor electrical potential across positive and negative electrodes. The method includes determining a full-cell open-circuit voltage (“OCV”), an associated positive half-cell OCV, and an associated negative half-cell OCV at a start-of-life point of the DC power source. A lithium balance model is executed to determine a plurality of beginning states associated with an electrode alignment of the DC power source. An in-use state for the full-cell OCV is determined. An optimization routine is executed employing the lithium balance model to determine in-use states associated with the electrode alignment of the DC power source based upon the in-use state for the full-cell OCV and the beginning states associated with electrode alignment. A negative-to-positive (“N/P”) ratio is determined based upon the in-use states, and battery life is evaluated based upon the N/P ratio.

Abstract: A method avoids lithium plating of a negative electrode in a battery cell. A voltage level of a positive electrode is determined in an initial battery charging process having a charging power level. A charging rate is modified in response to the determined voltage by increasing or decreasing the charging rate when the voltage is respectively less or greater than a voltage threshold. A charging profile is recorded for the power level. A subsequent charging process at the same power level is controlled using the recorded profile, which is possibly age-indexed to an age of an actual battery used in the subsequent charging process. A system includes the battery cell and a battery cell cycler device programmed to execute the method. An electric machine may be connected to the battery cell and a load, with a controller controlling the subsequent charging process using the profiles.

Abstract: An electrode material for an electrochemical cell is provided. The electrode includes a porous hydrophilic substrate, an electroactive material, and a binder. The porous hydrophilic substrate includes a plurality of voids and may be formed from cellulose or cellulosic derivative material. The electroactive material is dispersed in at least a portion of the voids of the hydrophilic substrate. In other aspects, another electrode material for an electrochemical cell is provided. The electrode includes a porous hydrophilic substrate, an electroactive material, an electrically conductive particle, and a binder. The porous hydrophilic substrate includes a plurality of voids and may be formed from cellulose or cellulosic derivative material. The electroactive material and the electrically conductive particle are dispersed in at least a portion of the voids of the hydrophilic substrate. In still other aspects, the porous hydrophilic substrate comprises a coating that is electrically conductive.

Abstract: System and methods for estimating a relationship between a SOC and an OCV of a battery system included in a vehicle are presented. In certain embodiments, an initial relationship between an open circuit voltage (“OCV”) and a state of charge (“SOC”) of a cell of the battery system may be determined at a beginning of life of the cell. Changes in one or more stoichiometric points of a half-cell of the cell may be determined as the cell ages. Based on the determined stoichiometric point changes of the half-cell, an initial relationship between the OCV and the SOC of the cell may be adjusted to generate an updated relationship between the OCV and the SOC of the cell.