Electrochemical cell charge / discharge management including partial cycle control

Abstract

In general, the present invention provides an electrochemical cell and battery management system. Such a system may include an electrochemical cell and a controller. In some cases, such a controller may be used to control various aspects of the charging and / or discharging of such an electrochemical cell. In some cases, the system may include one or more strings of cells.

Description

[Technical field]

[0001] (Related Applications) This application is a joint venture under 35 U.S.C. § 119(e) with U.S. Provisional Application No. 63 / 146,512, filed on February 5, 2021, and entitled “Charge / Discharge Management in Electrochemical Cells, Including Partial Cycle Control.” U.S. Provisional Application No. 63 / 184,639, filed May 5, 2021, and entitled "Charge / Discharge Management in Electrochemical Cells, Including Partial Cycle Control," and This application claims priority to U.S. Provisional Application No. 63 / 240,859, filed September 3, 2021, and entitled "Charge / Discharge Management in Electrochemical Cells, Including Partial Cycle Control," which is incorporated by reference in its entirety for all purposes.

[0002] The present invention relates generally to charge / discharge management of electrochemical cells and related systems. [Background technology]

[0003] Historically, batteries have been unable to compete successfully with established power sources such as the internal combustion engine in various industries such as automotive. One reason for this failure is that battery users have been dissatisfied with the life and performance that batteries have traditionally offered. Summary of the Invention

[0004] Disclosed herein are embodiments relating to charge and discharge management of electrochemical cells and related systems. The subject matter of the invention in some cases includes interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0005] Some embodiments include a method for charging an electrochemical cell comprising: at least one controller configured to control the cell such that the cell is charged over a first state of charge range having an amplitude of at least 20%; an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spans at least 2% of the first state of charge range, and the second portion spans at least 2% of the first state of charge range; The first portion occurs before the second portion.

[0006] Some embodiments include controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 20%; an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spans at least 2% of the first state of charge range, and the second portion spans at least 2% of the first state of charge range; wherein the first portion occurs before the second portion.

[0007] Some embodiments, when executed by at least one processor, cause the at least one processor to: controlling the electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 20%; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spans at least 2% of the first state of charge range, and the second portion spans at least 2% of the first state of charge range; at least one computer readable storage medium, wherein the first portion occurs before the second portion.

[0008] Some embodiments include a method for charging an electrochemical cell, comprising: at least one controller configured to control the cell such that the cell is charged over a first state of charge range having an amplitude of at least 2% and at most 90% and then charged over a second state of charge range; an average charge rate in said first state of charge range is at most 0.5 times the average charge rate in said second state of charge range.

[0009] Some embodiments include controlling an electrochemical cell such that the cell is charged over a first state of charge range having an amplitude of at least 2% and at most 90% and then charged over a second state of charge range; wherein the average charge rate in said first state of charge range is at most 0.5 times the average charge rate in said second state of charge range.

[0010] Some embodiments, when executed by at least one processor, cause the at least one processor to: controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 90% and then charged over a second state of charge range; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: an average charge rate in the first state of charge range is at most 0.5 times an average charge rate in the second state of charge range.

[0011] Some embodiments relate to an electrochemical cell management system including an electrochemical cell and at least one controller, which may be configured to control the cell to be charged over a first state of charge range having a width of at least 2% and at most 40%, then over a second state of charge range having a width of at least 2%, then over a third state of charge range having a width of at least 2%, wherein a charge rate in the first state of charge range is lower than an average charge rate in the second state of charge range, and wherein the average charge rate in the second state of charge range is lower than an average charge rate in the third state of charge range.

[0012] Some embodiments include controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 40%, then over a second state of charge range having a width of at least 2%, and then over a third state of charge range having a width of at least 2%. Including, a charging rate in the first state of charge range is lower than an average charging rate in the second state of charge range; wherein the average charge rate in the second state of charge range is lower than the average charge rate in a third state of charge range.

[0013] Some embodiments, when executed by at least one processor, cause the at least one processor to: controlling an electrochemical cell such that the cell is charged over a first state of charge range having an amplitude of at least 2% and at most 40%, then over a second state of charge range having an amplitude of at least 2%, and then over a third state of charge range having an amplitude of at least 2%. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: a charging rate in the first state of charge range is lower than an average charging rate in the second state of charge range; an average charge rate in the second state of charge range is lower than an average charge rate in the third state of charge range.

[0014] Some embodiments relate to an electrochemical cell management system including an electrochemical cell and at least one controller, which may be configured to monitor at least one characteristic of the cell indicative of lithium loss in the cell and to control a charge or discharge rate of the cell based on the at least one monitored characteristic of the cell.

[0015] Some embodiments include monitoring at least one characteristic of the cell indicative of a loss of lithium in the cell; and controlling a charge rate or a discharge rate of the cell based on at least one monitored characteristic of the cell. The present invention relates to a method for managing an electrochemical cell, comprising:

[0016] Some embodiments include When executed by at least one processor, the at least one processor monitoring at least one characteristic of the cell indicative of a loss of lithium in the cell; and controlling a charge rate or a discharge rate of the cell based on at least one monitored characteristic of the cell. The present invention relates to at least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising:

[0017] Some embodiments relate to an electrochemical cell management system that includes an electrochemical cell and at least one controller. The at least one controller comprises: Analyzing the cycle history of the cell; Controlling the cell to discharge the cell to meet the criteria if none of the most recent cycles meet the criteria for the most recent number of cycles in the cycle history. It may be configured as follows: the criteria includes discharging the cell at a discharge rate that is at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; The number of most recent cycles is at least 5.

[0018] Some embodiments relate to a method of electrochemical cell management, comprising analyzing a cycle history of an electrochemical cell, and controlling the cell to discharge the cell to meet a criterion if none of the most recent cycles meet the criterion for a number of most recent cycles in the cycle history, the criterion may include discharging the cell at a discharge rate that is at least twice the average charge rate of any of the most recent cycles over a state of charge range having a width of at least 2% and at most 60%, the number of most recent cycles being at least 5.

[0019] Some embodiments, when executed by at least one processor, cause the at least one processor to: Analyzing the cycle history of the electrochemical cell; and controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; The present invention relates to at least one computer readable storage medium encoded with executable instructions for carrying out a method of electrochemical cell care, comprising: wherein the criteria may include the cell being charged at a charge rate that is at least twice the average discharge rate of any cycle in the most recent cycles over a state of charge range having a width of at least 2% and at most 60%, the number of most recent cycles being at least 5 cycles.

[0020] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller. The at least one controller comprises: Analyzing the cycle history of the cell; Controlling the cell to discharge the cell to meet the criteria if none of the most recent cycles meet the criteria for a most recent number of cycles in the cycle history. It may be configured as follows: the criteria including discharging the cell at a discharge rate that is at least twice the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and no more than 60% wide; said discharge rate is at most four times the maximum recommended continuous discharge rate; The number of most recent cycles is at least 5.

[0021] Some embodiments include Analyzing the cycle history of the electrochemical cell; and controlling the cell to discharge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; Including, the criteria including discharging the cell at a discharge rate that is at least twice the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and no more than 60% wide; said discharge rate is at most four times the maximum recommended continuous discharge rate; The present invention relates to an electrochemical cell management method, wherein the number of most recent cycles is at least 5 cycles.

[0022] Some embodiments, when executed by at least one processor, cause the at least one processor to: Analyzing the cycle history of the electrochemical cell; and controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: the criteria includes discharging the cell at a discharge rate that is at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; said discharge rate is at most four times the maximum recommended continuous discharge rate; The number of most recent cycles is at least 5; At least one computer readable storage medium.

[0023] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller comprising: Analyzing the cycle history of the cell; controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; It may be configured as follows: the criteria include charging the cell at a charge rate that is at most 0.5 times the average discharge rate of any five cycles over a state of charge range that is at least 2% and at most 60% wide; The number of most recent cycles is at least 5.

[0024] Some embodiments include Analyzing the cycle history of the electrochemical cell; and controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; Including, the criteria include charging the cell at a charge rate that is at most 0.5 times the average discharge rate of any five cycles over a state of charge range that is at least 2% and at most 60% wide; A method for managing an electrochemical cell, the number of most recent cycles being at least 5 cycles. Regarding.

[0025] Some embodiments, when executed by at least one processor, cause the at least one processor to: Analyzing the cycle history of the electrochemical cell; and controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: the criteria include charging the cell at a charge rate that is at most 0.5 times the average discharge rate of any five cycles over a state of charge range that is at least 2% and at most 60% wide; The at least one computer readable storage medium, wherein the number of most recent cycles is at least five cycles.

[0026] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller may be configured to control the cell such that the cell is discharged and then charged, For at least a portion of the discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during the portion of the discharge is at least twice the average charge rate during at least a portion of the charge.

[0027] Some embodiments include controlling an electrochemical cell such that the cell is discharged and then charged. Including, The present invention relates to a method of electrochemical cell management, wherein for at least a portion of a discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during said portion of the discharge is at least twice the average charge rate during at least a portion of the charge.

[0028] Some embodiments include When executed by at least one processor, the at least one processor controlling an electrochemical cell so that the cell is discharged and then charged; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: For at least a portion of a discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during the portion of the discharge is at least twice an average charge rate during at least a portion of the charge.

[0029] Some embodiments relate to an electrochemical cell management system that includes an electrochemical cell and at least one controller. The at least one controller comprises: Analyzing the cycle history of the cell; When a threshold state of charge is reached during discharge, the discharge rate of the cell is increased to at least twice the average charge rate of at least a portion of at least one cycle in the cycle history. and configured to control the cell such that The threshold state of charge has a value less than or equal to 60%.

[0030] Some embodiments include analyzing the cycle history of the cell; and controlling the cell such that upon reaching a threshold state of charge during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least a portion of at least one cycle of a cycle history. Including, The threshold state of charge has a value of 60% or less.

[0031] Some embodiments include When executed by at least one processor, the at least one processor analyzing the cycle history of the cell; and controlling the cell such that when a threshold state of charge is reached during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least one cycle in a cycle history; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: The threshold state of charge has a value of 60% or less.

[0032] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller comprising: Analyzing the cycle history of the cell; controlling the cell such that when a threshold state of charge is reached during discharge, the discharge rate of the cell is increased to at least twice the average charge rate of at least a portion of at least one cycle in the cycle history; It may be configured as follows: The threshold state of charge has a value less than or equal to 60%.

[0033] Some embodiments include Analyzing the cycle history of the electrochemical cell; and controlling the cell such that upon reaching a threshold state of charge during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least a portion of at least one cycle of a cycle history. Including, The threshold state of charge has a value of 60% or less.

[0034] Some embodiments include When executed by at least one processor, the at least one processor analyzing the cycle history of the cell; and controlling the cell such that when a threshold state of charge is reached during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least a portion of at least one cycle of a cycle history; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: The threshold state of charge has a value of 60% or less.

[0035] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller comprising: At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of the terminated charging step. The cell is controlled so that It is configured as follows: The final state of charge has a value of 60% or less.

[0036] Some embodiments include At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of the terminated charging step. To control the electrochemical cell so that Including, The method relates to a method of managing an electrochemical cell, wherein said final state of charge has a value of 60% or less.

[0037] Some embodiments include When executed by at least one processor, the at least one processor At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of the terminated charging steps. Controlling the cell. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: The at least one computer readable storage medium, wherein the ending state of charge has a value of 60% or less.

[0038] Some embodiments relate to an electrochemical cell management system that includes an electrochemical cell and at least one controller. The at least one controller comprises: Analyzing the cycle history of the cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycle history; Controlling the Cell It may be configured as follows: The final state of charge has a value of 60% or less.

[0039] Some embodiments include Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycle history. Controlling the cell. Including, The method relates to a method of managing an electrochemical cell, wherein said final state of charge has a value of 60% or less.

[0040] Some embodiments include When executed by at least one processor, the at least one processor Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycle history. Controlling the cell. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: The at least one computer readable storage medium, wherein the ending state of charge has a value of 60% or less.

[0041] Some embodiments relate to an electrochemical cell management system that includes an electrochemical cell and at least one controller. The at least one controller comprises: Analyzing the cycle history of the cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history; Controlling the Cell It may be configured as follows: The final state of charge has a value of 60% or less.

[0042] Some embodiments include Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history over a state of charge range having a width of at least 1%. Controlling the cell. Including, The method relates to a method of managing an electrochemical cell, wherein said final state of charge has a value of 60% or less.

[0043] Some embodiments include When executed by at least one processor, the at least one processor Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history over a state of charge range having a width of at least 1%. Controlling the cell. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: The at least one computer readable storage medium, wherein the ending state of charge has a value of 60% or less.

[0044] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller. The at least one controller may be configured to control the cell such that the cell is discharged and then charged over a state of charge range having a width of at least 2% and at most 60%. In some examples, a discharge rate during the discharging is at least twice the average charge rate during the charging.

[0045] Some embodiments include controlling an electrochemical cell such that the cell is discharged and then charged over a state-of-charge range having a width of at least 2% and at most 60%; In some embodiments, the discharge rate during said discharging is at least twice the average charge rate during said charging.

[0046] Some embodiments include When executed by at least one processor, the at least one processor controlling an electrochemical cell so that the cell is discharged and then charged; In some embodiments, the discharge rate during the discharging is at least twice as fast as the average charge rate during the charging.

[0047] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller comprising: determining whether a fast charge request has been received; If a fast charge request is not received, control the cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 60% and then over a second state of charge range. In some embodiments, the charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range.

[0048] Some embodiments include determining whether a fast charging request has been received; and controlling the electrochemical cell to be charged over a first state of charge range having a width of at least 2% and at most 60% and then over a second state of charge range when no fast charge request is received; According to some embodiments, the charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range.

[0049] Some embodiments include When executed by at least one processor, the at least one processor determining whether a fast charging request has been received; and controlling the electrochemical cell to be charged over a first state of charge range having a width of at least 2% and at most 60% and then over a second state of charge range when no fast charge request is received; According to some embodiments, a charge rate in the first state of charge range is at most 0.5 times an average charge rate in the second state of charge range.

[0050] Some embodiments relate to an electrochemical cell management system comprising an electrochemical cell and at least one controller, the at least one controller comprising: controlling the cell such that the cell is discharged and then immediately charged over a first state of charge range having an amplitude of at least 2% and at most 60%, and a future charging schedule is set such that a criterion is met by the end of four cycles that go through the first state of charge range; Schedule future charging In some examples, the criteria include the cell being charged in a second state of charge range such that a charge rate in the first state of charge range is at most 0.5 times an average charge rate in the second state of charge range.

[0051] Some embodiments include controlling an electrochemical cell such that the cell is discharged and then immediately charged over a first state-of-charge range having a width of at least 2% and at most 60%, and setting a future charging schedule to meet the criteria by the end of four cycles that go through the first state-of-charge range; and executing said future charging schedule; According to some embodiments, the criteria includes charging the cell over a second state of charge range such that the charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range.

[0052] Some embodiments include When executed by at least one processor, the at least one processor controlling an electrochemical cell such that the cell is discharged and then immediately charged over a first state-of-charge range having a width of at least 2% and at most 60%, and setting a future charging schedule to meet the criteria by the end of four cycles that go through the first state-of-charge range; and executing said future charging schedule; According to some embodiments, the criteria includes the cell being charged over a second state of charge range such that a charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range.

[0053] Some embodiments of the present invention include at least one battery including two or more strings of cells, each string of cells including two or more cells; a multiplexing switch device connected to each string of cells; at least one controller configured to use the multiplexing switch device to transition between discharging the cells of the first string and discharging the cells of the second string while maintaining a voltage difference between the first string and the second string below a threshold voltage difference; The present invention relates to a battery management system comprising:

[0054] Some other embodiments include: at least one battery including two or more strings of cells, each string of cells including two or more cells; a multiplexing switch device connected to each string of cells; at least one controller configured to use a multiplexing switch device to transition between discharging the cells of the first string and discharging the cells of the second string while maintaining an overall output voltage of the battery within a window; The present invention relates to a battery management system comprising:

[0055] A further embodiment comprises at least one battery including two or more strings of cells, each string of cells including two or more cells; a multiplexing switch device connected to each string of cells; at least one controller configured to use a multiplexing switch device to transition between discharging the cells of the first string and discharging the cells of the second string while maintaining an inrush current resulting from the transition below a threshold current; The present invention relates to a battery management system comprising:

[0056] Some other embodiments include: at least one battery including two or more strings of cells, each string of cells including two or more cells; a multiplexing switch device connected to each string of cells; at least one controller configured to control, using a multiplexing switch device, a duration of a pulse discharge of at least one of the strings of cells based on at least one criterion; The present invention relates to a battery management system comprising:

[0057] A further embodiment comprises at least one battery including two or more strings of cells, each string of cells including two or more cells; an integrated switching control system including at least one switch connected to each string of cells; Equipped with The battery pack includes an integrated switching control system configured to control at least one switch to discharge a first string having a first voltage when measured, while discharging the first string and not discharging the second string, and then discharge a second string having a second voltage when measured that is closest to the first voltage.

[0058] Some other embodiments include: transitioning between discharging the first string and discharging the second string while maintaining a voltage difference between the first string and the second string below a threshold voltage difference using a multiplexing switch device connected to two or more cell strings of the at least one battery; Including, The present invention relates to a battery management method, in which each string of cells includes two or more cells.

[0059] A further embodiment comprises Using a multiplexing switch device connected to two or more cell strings of at least one battery to transition between discharging a first string and discharging a second string while maintaining an overall output voltage of the battery within a window. Including, The present invention relates to a battery management method, in which each string of cells includes two or more cells.

[0060] Some other embodiments include: Transitioning between discharging a first string and discharging a second string while maintaining an inrush current resulting from the transition below a threshold current using a multiplexing switch device connected to two or more cell strings of at least one battery. Including, The present invention relates to a battery management method, in which each string of cells includes two or more cells.

[0061] Some embodiments of the present invention include at least one battery including two or more strings of cells, each string of cells including two or more cells; a multiplexing switch device connected to each string of cells; at least one controller configured to use a multiplexed switch device to selectively discharge the strings of cells; The present invention relates to a battery management system comprising:

[0062] Some other embodiments include: at least one battery including two or more strings of cells, each string of cells including two or more cells; an integrated switching control system including at least one switch connected to each string of cells; Equipped with The present invention relates to a battery pack in which an integrated switching control system is configured to control at least one switch to discharge a string of cells.

[0063] Further embodiments relate to a battery management method, comprising using a multiplexing switch device coupled to two or more strings of cells of at least one battery to selectively discharge each string of cells. may include Each string of cells contains two or more cells.

[0064] Some other embodiments are an electrochemical cell, and During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. and configured to control the cell so that At least one controller An electrochemical cell management system comprising: Regarding.

[0065] A further embodiment comprises During the charging step, the electrochemical cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. and controlling the cell so that A method for managing an electrochemical cell, comprising: Regarding.

[0066] Some embodiments include When executed by at least one processor, the at least one processor During the charging step, the electrochemical cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. To control the electrochemical cell so that at least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method comprising: Regarding.

[0067] Some other embodiments include: an electrochemical cell, and During the discharging step, the cell is discharged at a first discharge rate over a first state of charge range having an amplitude of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; The second discharge rate is less than twice the corresponding charge rate. and configured to control the cell so that At least one controller The present invention relates to an electrochemical cell management system comprising:

[0068] A further embodiment comprises During the discharging step, the electrochemical cell is discharged at a first discharge rate over a first state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; said second discharge rate being less than twice the corresponding charge rate; Controlling the cell. The present invention relates to a method for managing an electrochemical cell, comprising:

[0069] Some embodiments include When executed by at least one processor, the at least one processor During the discharging step, the electrochemical cell is discharged at a first discharge rate over a first state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; and said second discharge rate being less than twice the corresponding charge rate; Controlling an electrochemical cell at least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method comprising: Regarding.

[0070] Some other embodiments include: an electrochemical cell, and During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; the first charge rate is at most 0.5 times the corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. and configured to control the cell so that At least one controller An electrochemical cell management system comprising: Regarding.

[0071] A further embodiment comprises During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; the first charge rate is at most 0.5 times the corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. Controlling the cell. The present invention relates to a method for managing an electrochemical cell, comprising:

[0072] Some embodiments include When executed by at least one processor, the at least one processor During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; the first charge rate is at most 0.5 times the corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. Controlling an electrochemical cell at least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method comprising: Regarding.

[0073] Other advantages and novel features of the present invention will become apparent from the following detailed description of various non-limiting embodiments of the invention when considered in conjunction with the accompanying drawings. In the event that this specification and a document incorporated by reference contain conflicting and / or inconsistent disclosure, the present specification shall control. [Brief description of the drawings]

[0074] Non-limiting embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, which are schematic and are not intended to be drawn to scale, in which each identical or nearly identical component shown is typically represented by a single numeral, and for the sake of clarity, not every component is necessarily labeled in every figure, nor are the figures necessarily all components of each embodiment of the present invention shown, unless necessary to enable a person skilled in the art to understand the invention. [Figure 1A] FIG. 1 is a block diagram illustrating an exemplary electrochemical cell management system, according to some embodiments. [Figure B] FIG. 1 is a circuit diagram illustrating an exemplary simplified electrochemical cell model, according to some embodiments. [Figure 1C] FIG. 1 is a block diagram illustrating a representative battery management system, according to some embodiments. [Figure 1D] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 1E]FIG. 1 is a block diagram illustrating an exemplary battery management system having cell strings, in accordance with some embodiments. [Figure 1F] FIG. 2 is a block diagram illustrating an exemplary battery management system during a representative charging sequence, in accordance with some embodiments. [Figure 1G] FIG. 2 is a block diagram illustrating an exemplary battery management system during a representative charging sequence, in accordance with some embodiments. [Figure 1H] FIG. 2 is a block diagram illustrating an exemplary battery management system during a representative charging sequence, in accordance with some embodiments. [Figure 1I] FIG. 2 is a block diagram illustrating an exemplary battery management system during a representative charging sequence, in accordance with some embodiments. [Figure 1J] FIG. 2 is a block diagram illustrating an exemplary battery management system during a representative charging sequence, in accordance with some embodiments. [Figure 1K] FIG. 2 is a block diagram illustrating an exemplary battery management system during an exemplary discharge sequence, in accordance with some embodiments. [Figure 1L] FIG. 2 is a block diagram illustrating an exemplary battery management system during an exemplary discharge sequence, in accordance with some embodiments. [Figure 1M] FIG. 2 is a block diagram illustrating an exemplary battery management system during an exemplary discharge sequence, in accordance with some embodiments. [Figure 1N] FIG. 2 is a block diagram illustrating an exemplary battery management system during an exemplary discharge sequence, in accordance with some embodiments. [Figure 2A] 1 is a flowchart illustrating an exemplary method for managing an electrochemical cell, according to some embodiments. [Figure 2B] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 2C] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 2D]1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 3A] 1 is a flowchart illustrating an exemplary method for managing an electrochemical cell, according to some embodiments. [Figure 3B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 3C] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 3D] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 4A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 4B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 5A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 5B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 6A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 6B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 7A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 7B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 8A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 8B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 9A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 9B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 10A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 10B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 10C] 1 is a capacity-cycle graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 11A] 4 is a flow chart illustrating an additional representative method for managing an electrochemical cell, according to some embodiments. [Figure 11B] 1 is a charge-time graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 11C] FIG. 1 is a block diagram illustrating a representative battery pack, according to some embodiments. [Figure 12A] FIG. 1 is a block diagram illustrating a representative battery management system, according to some embodiments. [Figure 12B] FIG. 2 is a block diagram illustrating a representative set of cells and corresponding components, according to some embodiments. [Figure 12C] 1A-1D are cross-sectional schematic diagrams illustrating the application of an anisotropic force to one or more electrochemical cells according to some embodiments. [Figure 12D] FIG. 1 is a cross-sectional schematic diagram of an electrochemical cell according to some embodiments. [Figure 13A] FIG. 2 illustrates an exemplary discharge profile according to some embodiments. [Figure 13B]FIG. 2 illustrates an exemplary full discharge profile, according to some embodiments. [Figure 13C] 1 is a chart illustrating cycle life of an exemplary cell, according to some embodiments. [Figure 13D] FIG. 2 illustrates an exemplary charging rate profile, according to some embodiments. [Figure 13E] FIG. 2 illustrates an exemplary charge capacity profile, according to some embodiments. [Figure 13F] FIG. 2 illustrates an exemplary charging voltage profile according to some embodiments. [Figure 13G] 1 is a capacity-cycle graph of an exemplary electrochemical cell management system, according to some embodiments. [Figure 13H] 1 is a capacity-cycle graph of an additional exemplary electrochemical cell management system, according to some embodiments. [Figure 13I] 1 is a capacity-cycle graph of an additional exemplary electrochemical cell management system, according to some embodiments. [Figure 13J] 1 is a capacity-cycle graph of an additional exemplary electrochemical cell management system, according to some embodiments. [Figure 13K] 1 is a capacity-cycle graph of an additional exemplary electrochemical cell management system, according to some embodiments. [Figure 13L] 1 is a capacity-cycle graph of an additional exemplary electrochemical cell management system, according to some embodiments. [Figure 14] FIG. 1 is a block diagram illustrating a representative computing system that may be used to implement certain aspects. [Figure 15A] 4 is a flowchart illustrating an exemplary method for discharging a string of cells of a battery, according to some embodiments. [Figure 15B] 4 is a flowchart illustrating an exemplary method for discharging a string of cells of a battery, according to some embodiments. [Figure 15C]4 is a flowchart illustrating an exemplary method for discharging a set of cells of a battery, according to some embodiments. [Figure 15D] 5 is a flowchart illustrating an additional representative method for discharging a set of cells of a battery, according to some embodiments. [Figure 16] 4 is a flowchart illustrating an exemplary method for controlling a battery pack, according to some embodiments. [Figure 17A] 5 is a flowchart illustrating an additional representative method for controlling a battery pack, according to some embodiments. [Figure 17B] FIG. 1 is a schematic diagram illustrating an exemplary battery management system, according to some embodiments. [Figure 17C] 4 is a flowchart illustrating an additional representative method for discharging a string of cells of a battery, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] The present inventors recognize and understand that conventional techniques for the management and operation of rechargeable electrochemical cells have previously resulted in poor life and performance of the cells (and the batteries in which they may be included). For example, the cells have suffered from a short cycle life (e.g., a low number of full charge and discharge cycles before the capacity drops below 80% of the original capacity), especially when the charge and discharge rates are similar or when the charge rate is higher than the discharge rate, as the cells typically do at some point after substantial use. For example, many users of the cells of batteries have desired their batteries to have nearly identical charge and discharge rates (e.g., 4 hours to charge and 4 hours to discharge), and battery manufacturers have provided batteries and battery management systems that provide such nearly identical rates. Also, many users have desired to charge at a rate higher than the rate at which the battery discharges (e.g., 30 minutes to charge and 4 hours to discharge) for a variety of reasons, such as reducing the inconvenience of waiting for a charge to use the battery or extending the runtime.

[0076] As used herein, the term "full charge cycle" is generally used to refer to a period during which the cell is charged to about 100% of its recharge capacity, and the term "full discharge cycle" is generally used to refer to a period during which the cell is discharged to about 100% of its discharge capacity (which may differ from its recharge capacity), while the term "charge step" is generally used to refer to a continuous period during which charging occurs without discharging, and the term "discharge step" is generally used to refer to a continuous period during which discharging occurs without charging.

[0077] The term "charge cycle" is generally used to refer to a period during which the cell is charged, which does not necessarily have to be a complete charge cycle. The term "discharge cycle" is generally used to refer to a period during which the cell is discharged, which does not necessarily have to be a complete discharge cycle. The term "previous discharge cycle" is generally used to refer to a period during which the cell was or is being discharged. For example, this "previous" discharge cycle may be complete or may still be in progress, and does not necessarily refer to a recently completed discharge step that sums to about 100% of the discharge capacity of the cell. If a complete discharge cycle has not been performed, the previous discharge cycle may refer to a previously completed discharge step.

[0078] The term "capacity" is generally used to refer to the amount of charge the cell can deliver at a given or rated voltage, often measured in ampere-hours (such as milliamp-hours or mAh). In some embodiments, capacity may be the mAh the cell can hold at a given time (which may vary over multiple charge or discharge cycles), the mAh remaining in the cell at a given time, or the mAh the cell requires to fully recharge.

[0079] As used herein, the term "state of charge" (SOC) is used to refer to the level of charge relative to the capacity of a cell, measured in percentage. As an example, a 100% state of charge refers to a fully charged cell, a 40% state of charge refers to a cell that retains 40% of its capacity, and a 0% state of charge refers to a fully discharged cell.

[0080] As used herein, the term "state of charge range" (SOC range) refers to a range of states of charge. For example, a state of charge of 10% to 50% includes 10%, 50%, and all states of charge between 10% and 50%.

[0081] As used herein, the "width" of a state of charge range is used to refer to the absolute value of the difference between the endpoints of the state of charge range. As an example, a state of charge range of 10% to 50% has a width of 40% (because 50% minus 10% is 40%). As another example, a state of charge range of at least 2% and at most 5% would have a width of 3% (because 5% minus 2% is 3%).

[0082] The inventors recognize and understand that the cycle life of the cells (and batteries containing the cells), and therefore the life and performance of the cells (and batteries), may be significantly improved by employing high ratios of discharge rate to charge rate. Furthermore, the inventors recognize and understand that these ratios may be employed by providing a cell and / or battery management system that controls the cells to provide such ratios.

[0083] The inventors recognize and appreciate that the cycle life of the cells (and batteries containing the cells), and therefore the life and performance of the cells (and batteries), may be significantly improved by employing a high ratio of discharge rate to charge rate. Furthermore, the inventors recognize and appreciate that these ratios may also be employed in high voltage (e.g., 60 volts or greater) applications by providing a battery management system that controls strings of the cells or modules in a battery to provide such ratios. For example, some embodiments relate to battery management systems that multiplex strings of cells such that the strings may be charged all or in multiples at once and discharged individually or in smaller sets. This can result in a practical ratio of cell discharge rate to charge rate that improves cycle life while providing the production rate desired or required for a particular load and application. Furthermore, the inventors recognize and appreciate that discharging some (but not all) of the strings at a time with a uniform current distribution may also improve cycle life.

[0084] For example, a battery having strings of four cells may discharge one string at a time at 0.5 amps each for three hours, then charge all four strings at 0.5 amps for 12 hours. This configuration results in an actual ratio of discharge rate to charge rate of 4:1, but from the user's perspective it would be a 1:1 ratio since the strings are individually discharged for three hours each (a total of 12 hours of discharge time). The inventors have recognized and appreciated that such a battery management system may actually improve the cycle life of the battery while providing what the user wants or needs from the battery. In some embodiments, the functionality that provides this twin benefit may be hidden from the user and integrated into the strings, cell blocks, and / or the battery itself. In some embodiments, a given string may include at least 15 cells.

[0085] The inventors recognize and appreciate that even higher voltage applications are possible by using such battery management systems with strings of cells or modules. For example, by connecting individual cells or modules of cells in series as a string, the total voltage of a given string and / or the voltage applied to a load can be much higher than the 4.1 volts that may be available from an individual cell. For example, the inventors recognize and understand that some applications require voltages of 60 volts, 80 volts, 110 volts, 220 volts, 300 volts, 400 volts, or even 800-2000 volts, and that such battery management systems with strings of cells or modules can provide any or all of these and other voltages.

[0086] The present inventors have recognized and understood that many applications, such as electric vehicles, require uninterrupted power and a nearly constant voltage. For example, an electric vehicle may not be able to provide the required acceleration or performance without uninterrupted power and a nearly constant voltage. The present inventors have recognized and understood that in such applications, when one string or cell is being discharged, the transition to the next string or cell should not be simply performed by terminating the discharge of that first string and then beginning the discharge of the second string, as this would result in an interruption in the power supply and a sudden voltage fluctuation. Rather, to avoid this complete interruption, the second string needs to begin discharging before the first string stops discharging.

[0087] The inventors have recognized and appreciated that voltage fluctuations can be further reduced or avoided by carefully selecting the string to be discharged. The first string (the string the system transitions to) typically has a different voltage than the second string (e.g., the first string often has a lower voltage due to higher usage, but the second string may also have a higher voltage). This change in voltage transitioning between the first and second strings results in an inrush current. The inventors have recognized and appreciated the importance of minimizing such inrush currents, since many battery management system circuits and electronic components are not designed to sustain high currents without burning out. The inventors have recognized and appreciated the importance of minimizing such inrush currents by carefully selecting the string to be discharged to minimize the voltage delta. Other methods of handling such inrush currents include using pre-charge circuits or similar components. However, such additional components add cost, complexity, volume, and weight to the battery system, which may be prohibitive or significantly disadvantageous in various applications, such as electric vehicles. The inventors recognize and appreciate that such disadvantages can be avoided using the embodiments described herein to carefully select discharging strings that minimize voltage fluctuations and resulting inrush currents.

[0088] The inventors recognize and appreciate that one may have such improvements as described herein, such as improved cell cycle life, even if all charge steps and / or all discharge steps do not meet the target ratio, and / or even if the ratio is employed over only a portion of the charge steps and / or discharge steps, and / or even if the ratio is employed over a state of charge range that makes up only a portion of the total SOC range.

[0089] For example, some embodiments relate to a cell management system that controls the cell to discharge or charge over an SOC range (e.g., a range having a width of at least 2% and at most 60%, or at most 50%, or at most 30%, or at most 20%) to satisfy the rate ratio (e.g., by discharging at a rate at least twice or four times the average charge rate before and after, or by charging to establish a similar ratio in discharge rate) and only satisfy this SOC range. In other words, outside this SOC range, the rate ratio is fundamentally different and not beneficial to the health of the cell, but inside this SOC range, the rate ratio is beneficial to the health of the cell. Also, other references in this specification to an SOC range having a width of at most a certain percentage mean, in some embodiments, that outside that SOC range, the aforementioned rate ratio is not satisfied.

[0090] As another example, some embodiments relate to cell management systems in which the cells are discharged or charged over an SOC range (e.g., a range having a width of at least 2% and at most 60%) and controlled to meet a rate ratio (e.g., by discharging at a rate at least twice the average charge rate of any of the last five cycles, or by charging to establish a similar ratio with the discharge rate). As another example, in some embodiments, if the ratio has not been met within the last five cycles, the cells are discharged over the SOC range to meet a different ratio (e.g., by discharging at a rate at least twice the average discharge rate of any of the last five cycles, but at most four times the maximum recommended continuous discharge rate).

[0091] As a further example, in some embodiments, the cell is charged over a SOC range to provide an increasing charge rate over that range. For example, the charge rate can be increased linearly, parabolically, or exponentially. The inventors recognize and appreciate that significantly longer cycle life (e.g., 50% longer cycle life compared to constant or decreasing rate charging conditions) can be achieved by charging the cell or cells more slowly at the beginning of the charging process and increasing the charge rate (e.g., gradually or not) over time. Charging at an increasing rate until the end of the charging process can be particularly beneficial. On the other hand, rapid charging can be particularly detrimental to cycle life, especially for lithium metal electrode active materials. Furthermore, the inventors recognize and appreciate that increasing charge rates may still be used while providing an average overall charge rate required by the application or user. The inventors also recognize and appreciate that by controlling the charge rate in such a manner, many of the advantages described herein may be achieved regardless of the discharge rate or any ratio between the charge rate and the discharge rate. The inventors further recognize and understand that the charge rate is easier to control than the discharge rate and can follow a profile beneficial to the cell (e.g., the discharge demands of the load may be significantly outside of ideal cell conditions but must still be met quickly, whereas charging may have much more time for better cell treatment and is more likely to be controlled by an algorithm).

[0092] In some embodiments, the cell may be discharged over additional SOC ranges to provide a decreasing discharge rate over those ranges. The inventors recognize and appreciate that decreasing the discharge rate over the discharge step, especially in combination with increasing the charge rate over the charge step, can further improve cell cycle life.

[0093] As an additional example, in some embodiments, when a threshold SOC (e.g., below 60%) is reached during discharge, the discharge rate is increased to at least twice the average charge rate of at least one cycle in the cycle history. In some embodiments, the charging step is terminated (e.g., at 60% SOC) and discharge is initiated, where the cell is discharged at a rate at least twice the average charge rate of at least one cycle in the terminated charging step or cycle history, over an SOC range having a width of at least 1%. In additional embodiments, the cell is discharged over an SOC range (e.g., a range having a width of at least 2% and at most 60%, or at most 50%, or at most 30%, or at most 20%) and then charged such that the discharge rate is at least twice the average charge rate.

[0094] As an additional example, in some embodiments, when a threshold SOC (e.g., below 60%) is reached during discharge, the discharge rate is increased to at least twice the average charge rate of at least a portion of at least one cycle in the cycle history. In some embodiments, the charging process is terminated (e.g., at 60% SOC) and discharge is initiated, where the cell is discharged at a rate at least twice the average charge rate of at least a portion of at least one cycle in the terminated charging process or cycle history over an SOC range having a width of at least 1%. In further embodiments, the cell is discharged over an SOC range (e.g., a range having a width of at least 2% and at most 60%, or at most 50%, or at most 30%, or at most 20%) and then charged such that the discharge rate is at least twice the average charge rate.

[0095] In further embodiments, if no fast charge request is received, the cell is charged over a first SOC range (e.g., a range having a width of at least 2% and a width of at most 60%, or at most 50%, or at most 30%, or at most 20%) and then charged over a second SOC range such that the rate in the first SOC range is at most 0.5 times the average rate in the second SOC range. In some embodiments, the cell is discharged and then immediately charged over the first SOC range (e.g., a range having a width of at least 2% and a width of at most 60%, or at most 50%, or at most 30%, or at most 20%), and a future charging schedule is set and executed such that by the end of the next four cycles, the cell is charged over the second SOC range such that the rate in the first SOC range is at most 0.5 times the average rate in the second SOC range.

[0096] Furthermore, the present inventors recognize and appreciate that the analysis and control as described herein may be performed by a cell and / or battery management system.

[0097] Some embodiments, such as those having multiple cells, relate to battery management systems that multiplex the cells so that they may be charged all at once (or discharged simultaneously) and discharged individually or in smaller sets. This can result in an actual ratio of discharge rate to charge rate (or discharge rate to other discharge rate, or charge rate to other charge rate) of the cells that improves cycle life while providing the output rate desired or required for a particular load or application. Additionally, the inventors recognize and appreciate that discharging some, but not all, of the cells at once with a homogenous current distribution may also improve cycle life.

[0098] For example, a battery having four such cells may discharge one cell at a time at 0.5 amps each for 3 hours, and then charge all four such cells at 0.5 amps for 12 hours. This configuration results in an actual ratio of discharge rate to charge rate of 4:1, but from the user's perspective it is a 1:1 ratio since each of the cells discharges for 3 hours (a total of 12 hours of discharge time). The inventors recognize and understand that such a battery management system may actually improve the cycle life of a battery while providing what a user wants or needs from a battery. In some embodiments, the functionality that provides these two benefits may be invisible to the user and may be built into the cell block and / or the battery itself.

[0099] The inventors have recognized and appreciated that the cycle life of a battery can be further improved by monitoring the cycles and various characteristics of the cells (such as the duration of connection between a load and the cell currently connected to the load, or a more complex function that considers multiple parameters) and selecting when to discharge the cells based on this monitoring, particularly as compared to prior art techniques that relied on very simple selection processes such as "round robin" or considering the number of previous discharge cycles.

[0100] FIG. 1A illustrates an exemplary cell management system 100. In some embodiments, the exemplary system 100 may include a controller (e.g., 114) and an electrochemical cell (e.g., 121A). In some embodiments, the cell 121A may be present alone. In other embodiments, additional cells (e.g., any of the cells 121B and 121C of FIG. 1A) and / or additional sets of cells (e.g., any of the cell sets 122 of FIG. 1A) may be present (e.g., to form a battery 120). Optionally, the system 100 may include one or more sensors (e.g., 116). Although only a single controller 114 and a single sensor 116 are shown in FIG. 1A, it should be understood that any suitable number of these components may be used. Any of a number of different implementations may be employed.

[0101] According to some embodiments, the cell 121A may include at least one lithium metal electrode active material. Furthermore, each set of cells (e.g., the cell set 121) may include one or more cells (e.g., 121A-121C). In some embodiments, each set of cells may comprise a single cell. Alternatively, each set of cells may include multiple cells and may form the cell "block," or multiple sets of cells may together form the cell block. Furthermore, each cell (either in a battery, all batteries in a battery pack, or in the set of cells) or the set of cells may utilize the same electrochemistry. That is, in some embodiments, each cell may utilize the same anode active material and the same cathode active material.

[0102] Some embodiments, such as those having multiple cells, may include a multiplexing switch device (not shown in FIG. 1A) as described in connection with FIG. 1B below, or an array of switches as further described in connection with FIG. 3A and 3B below. Further, a multiplexing switch device may be connected to each set of the cells and / or to each cell individually. In some embodiments, a controller, such as 114, may selectively discharge the sets of the cells using the multiplexing switch device.

[0103] In some embodiments, a controller (e.g., 114) may include one or more processors, which may be of any complexity appropriate to the application. Alternatively or additionally, a controller may include analog circuitry and / or logic devices less complex than a processor or microprocessor.

[0104] In some embodiments, the controller may control the cell such that, for at least a portion of the cell's charge cycle, the cell is charged at a charge rate or charge current that is lower than the discharge rate or discharge current of at least a portion of the previous discharge cycle. For example, the controller may cause the cell to be charged for a percentage of the cell's recharge capacity (e.g., anywhere from 1% to 100% of the recharge capacity) at a charge rate or charge current that is at least twice as slow (i.e., the charge rate or charge current is half the rate of the discharge rate or discharge current) as the discharge rate or discharge current that was used on average for a percentage of the cell's discharge capacity (e.g., anywhere from 1% to 100% of the discharge capacity). Alternatively or additionally, the controller may cause the cell to be charged at a charge rate or charge current that is at least four times slower than the discharge rate (e.g., this control results in the cell being charged for a percentage of the cell's recharge capacity at 1 / 4 the rate at which it was discharged for a percentage of the cell's discharge capacity over the last discharge / charge cycle). The present inventors recognize and understand that such a ratio of charge rate to discharge rate can improve the performance and cycle life of the cell.

[0105] In some embodiments, controlling the cell may include controlling when and how to start and stop charging and discharging, directing a discharge, increasing or decreasing a charge or discharge rate or current, etc. For example, controlling the charging or discharging of the cell may include starting a charge or discharge, stopping a charge or discharge, increasing or decreasing a charge or discharge rate or current, etc.

[0106] In some embodiments, the cell is charged such that over a period during which at least 5% (or at least 1%, or at least 10%, or at least 15%, or at least 25%, or anywhere in between) of the cell's capacity is charged, the average charge rate or average charge current is lower than the average discharge rate or average charge current used to discharge at least 5% (or at least 10%, or at least 15%, or at least 25%, or anywhere in between) of the cell's capacity during a previous discharge cycle, which may be, for example, the immediately preceding discharge cycle or a previous discharge cycle.

[0107] In some embodiments, the charging step is performed such that for at least 5% (or at least 10%, at least 25%, at least 50%, or at least 75%) of the capacity of the cell or battery, the average charge rate and / or charge current is less than 50% (or less than 35%, or less than 25%) of the average discharge rate and / or average discharge current at which at least 5% (or at least 10%, at least 25%, at least 50%, or at least 75%) of the capacity of the cell or battery was discharged during a previous discharge step.

[0108] In some embodiments, the average discharge rate or average discharge current during the immediately preceding discharge cycle may be equal to or less than the average charge rate or average charge current during the charge cycle, and the average discharge rate or average discharge current during the immediately preceding discharge cycle during discharging at least 5% of the cell's discharge capacity may be at least two times (or four times) higher than the average charge rate or average charge current during the charge cycle. The inventors recognize and understand that even if the average discharge rate of the cell is the same as or even slower than the charge rate, so long as the average discharge rate or average discharge current during discharging at least a portion (such as 5%) of the cell's discharge capacity during the previous discharge cycle is sufficiently (e.g., at least two, three, or four times) higher than the average charge rate or average charge current during that time.

[0109] As used herein, when the cell is charged at multiple different rates over a given period of time (e.g., over a portion of a charging step, over the entire charging step, or over a series of charging steps), the average charging rate over the given period is calculated as follows:

number

number

[0110] As used herein, when the cell is discharged at multiple different rates over a given period of time (e.g., over a given charging step or series of charging steps), the average discharge rate over the given period is calculated as follows:

number

number

[0111] The inventors recognize and appreciate that determining a charge rate that may improve the performance and cycle life of the cell, such as a lithium metal cell, involves a number of factors that may include discharge rate, the cell impedance, and / or the state of health (SOH) of the cell. In some embodiments, a controller may be aware of these factors because it may measure (such as via sensors 116) parameters or characteristics that may be used to determine each of them. A controller may directly or indirectly measure charge and discharge currents, coulombs added or removed, the cell impedance (capacitive and resistive), and / or the pressure, size, and / or thickness of the cell.

[0112] In some embodiments, the controller may monitor such characteristics of the cell. For example, the characteristics may include at least a portion of the discharge history of the cell. Alternatively or additionally, the characteristics may include at least one morphological characteristic of the cell. The controller may monitor any of these using sensors 116, such as pressure sensors, gauges to measure thickness, sensors to measure or determine surface roughness and / or pits (such as pits in the anode), and / or memory to store the charge / discharge history of the cell. For example, pressure sensors may be included to measure uniaxial pressure and / or gas pressure (such as to determine if the cell generates excessive amounts of gas). Alternatively or additionally, a gauge may be included to measure the thickness of the cell, and the controller may determine and monitor at least one rate of increase in thickness.

[0113] In some embodiments, the controller may use this information, such as the characteristics, to determine the charging method and / or rate to use, which may include controlling the rate or other parameters as described herein.

[0114] In some embodiments, a controller may consider any of several factors in determining the state of charge (SOC) and state of health (SOH) of the cell. For example, for the cell impedance, the cell model may be simplified as shown in FIG. 1E, which shows a resistor in series (RS) with a parallel combination of a resistor (RP) and a capacitor (C1). An impedance measurement may have two components, a real component and an imaginary component. The real component may simply be the DC resistance, R=RS+RP. The imaginary (or reactive) component in this case is XC: XC = 1 / (2πfc) (where f is frequency and c is capacitance.) which is inversely affected by frequency. The impedance (Z) can be found at any frequency and the phase angle given by the formula:

number

[0115] The present inventors have also recognized and understood that charge / discharge cycles and / or pulses of charge / discharge steps should not be applied faster than a rate equal to about two or three times the RC time constant, because at faster rates, most of the energy may not be available to charge or discharge the cell. Rather, it is mostly reactive, and most of the energy may be returned by capacitance or dissipated in resistance.

[0116] The inventors further recognize and understand that the cell will grow and shrink in thickness with each cycle, and some of the growth will be retained with each cycle. This growth and shrinkage may be measured by directly monitoring the pressure and / or size change of the cell. These are further inputs that may be used in determining SOC and SOH, and may also be used in determining how to charge the cell.

[0117] In some embodiments, a controller may control charging of the cell based on characteristics of the cell. For example, if the cell has had a discharge cycle or history of discharging at a certain discharge rate or current (such as 300 mA) for at least a portion of a previous discharge cycle, the cell may be controlled to charge at a lower rate or current (such as 150 mA or 75 mA) for at least a portion of a charge cycle.

[0118] In some embodiments involving induced discharge, the controller may control the cell such that for at least a portion of a charge cycle (e.g., 5% of the cycle), the cell is charged at a charge rate or charge current that is lower than the discharge rate or discharge current of at least a portion of a previous discharge cycle other than (i.e., not including) the induced discharge.

[0119] As another example, the controller may terminate use of the cell when the applied anisotropic pressure falls below a threshold, which may indicate that the pressure application system (examples of which are described in more detail below) is damaged. For example, in some embodiments, such a threshold may be 1%-50% of the nominal applied anisotropic pressure. Alternatively or additionally, the controller may terminate use of the cell if the pressure is too high or the thickness is increasing faster than a threshold. For example, in some embodiments, such a threshold rate may be 1%-3% or more of thickness increase per cycle.

[0120] FIG. 1C illustrates an exemplary battery management system 100. In some embodiments, such as those having multiple cells, the exemplary system 100 may include a multiplexing switch device (e.g., 112), a controller (e.g., 114), one or more sensors (e.g., 116), and one or more batteries (e.g., 120, 130, 140, 150, etc.). Although only a single multiplexing switch device 112, controller 114, sensor 116, and four batteries 120-150 are shown in FIG. 1C, it should be understood that any suitable number of these components may be used. Any of a number of different implementations may be employed. Additionally, although singular labels are used herein to refer to multiplexing switch devices, it should be understood that the components used for multiplexing and switching described herein may be distributed among any suitable number of devices (e.g., switches).

[0121] According to some embodiments, the battery may include at least one lithium metal battery. Additionally, the batteries (e.g., 120-150) may each include one or more cell sets (e.g., 121-124, 131-132, 141-142, 151-152, etc.), also referred to as a set of cells. In some embodiments, one or more cell sets or sets of cells may form a string or string of cells as described herein (in some embodiments, 121-124 may be referred to as a string). For example, a string of cells may include a module of cells or individual cells connected in series. In some embodiments, the cells of a module may be connected in parallel with each other within a module, while the modules may be connected in series with each other. Alternatively or additionally, the cells of a module may be connected in series with each other within a module. Alternatively or additionally, the modules may be connected in parallel with each other.

[0122] In some embodiments, two or more strings or sets of cells may be included in each battery, such as 121-122. Furthermore, each set of cells (e.g., cell set 121) may include one or more cells (e.g., 121A-121C). In some embodiments, each set of cells may have a single cell. Alternatively, each set of cells may include multiple cells and may form a cell "block," or multiple sets of cells may together form the cell block. Furthermore, each cell (either in a battery, all batteries in a battery pack, or in the set of cells) or the set of cells may utilize the same electrochemistry. That is, in some embodiments, each cell may utilize the same anode active material and the same cathode active material.

[0123] In some embodiments, the multiplexing switch device (e.g., 112) may include an array of switches as further described in connection with Figures 9A and 9B below. Further, the multiplexing switch device may be connected to each set of cells and / or to each cell individually. In some embodiments, a controller such as 114 may use the multiplexing switch device to selectively discharge cells, or sets of cells, based on at least one criterion.

[0124] In some embodiments, the controller may use a multiplexing switch device to selectively pulse-discharge the modules one at a time, sequentially moving through all of the modules in the battery.

[0125] For example, the criteria may include an order for discharging the set of cells, such as a predefined numbering or sequence associated with the set of cells (e.g., start with the first set, cycle through each set to the last set, then start over with the first set), and may also include an order based on the set of cells having a next higher voltage or some other indicator of next higher voltage. The inventors recognize and understand that the use of a sequence, and in particular a predefined numbering, reduces the complexity of the operations performed by the system (e.g., a non-microprocessor controller) and may be usable by a wider array of systems.

[0126] In some embodiments, a controller such as 114 may include at least one cell string controller (e.g., a cell string microcontroller) that monitors and manages at least one of the strings of cells. Additionally, the controller may include at least one battery management controller (e.g., a battery management microcontroller) configured to monitor and manage at least one parameter of at least one of the batteries. For example, the cell string microcontroller may in some embodiments monitor all strings of the battery management system and control multiplexing between strings (and charging and discharging of strings). Additionally, the battery management microcontroller may in some embodiments monitor a single string, and multiple battery management microcontrollers may be in communication with a single cell string microcontroller.

[0127] In some embodiments, the cell string microcontroller may include its own separate high voltage controller for connecting and disconnecting the string. Alternatively, each individual battery management microcontroller may include an integrated switch for the entire respective string that may turn the string on or off by command from the cell string microcontroller. In some embodiments, each battery management microcontroller may include at least one CAN bus and / or serial bus.

[0128] In some embodiments, the positions and roles of the battery management microcontroller and the cell string microcontroller may be interchanged. For example, the cell string microcontroller may determine the desired state of a given string by monitoring its voltage and current and by monitoring communication from the battery management microcontroller. In some embodiments, the switching waveforms produced by the cell string microcontroller may provide overlap and dead band requirements for switching appropriate to the application of the battery management system (e.g., load requirements - the battery management system may include switch multiplexing required to connect the cell strings in series, parallel, or series / parallel topologies required to meet the voltage and current requirements of the application). Additionally, the battery management microcontroller may monitor and control charging and discharging of the strings and cells to ensure safe operation of all components. The battery management microcontroller may also communicate with internal production, calibration, and test equipment as well as end users.

[0129] In some embodiments, a controller such as 114 may use a multiplexing switch device to transition between discharging a first string of cells (e.g., 121) and discharging a second string of cells (e.g., any of 122-124) while maintaining a voltage difference between the first string and the second string below a threshold voltage difference. For example, the threshold voltage difference may be such that an inrush current resulting from the transition is at most 15 amps. In some embodiments, the threshold voltage difference may be such that an inrush current resulting from the transition is at most 10 amps or at most 8 amps. According to some embodiments, keeping the voltage difference between the strings below such a threshold reduces voltage fluctuations and leads to improved or guaranteed performance for a load (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0130] In some embodiments, the threshold voltage difference may be at most 8% of the maximum total voltage of the first string or the second string. In some embodiments, the threshold voltage difference may be at most 5% of the maximum total voltage of the first string or the second string. In some embodiments, the maximum total voltage of a string is the maximum voltage for which the string is rated and / or the maximum voltage the string may have, which may be the voltage when fully charged. Using such a voltage difference threshold, according to some embodiments, can reduce voltage fluctuations, leading to improved or guaranteed performance for a load (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0131] In some embodiments, a controller such as 114 may use a multiplexing switch device to transition between discharging a first string of cells and discharging a second string of cells while maintaining the total output voltage of the battery within a window. For example, the window may be ±10% of the output voltage required by the load, such as 60 volts. According to some embodiments, maintaining the total output voltage within such a window reduces voltage fluctuations and improves or ensures performance (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0132] In some embodiments, a controller such as 114 may use a multiplexing switch device to transition between discharging a first string of cells and discharging a second string of cells while keeping the inrush current resulting from the transition below a threshold current. For example, the threshold current may be at most 15 amps. In some embodiments, the threshold current may be at most 10 amps.

[0133] In some embodiments, the threshold voltage difference is such that the inrush current resulting from the transition may be at most 15 amps. In some embodiments, the threshold voltage difference may be such that the inrush current resulting from the transition may be at most 10 amps.

[0134] According to some embodiments, keeping the inrush current resulting from the transition below a threshold current reduces voltage fluctuations, leading to improved or ensured performance (e.g., in electric vehicles) without reliance on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0135] In some embodiments, the controller may determine which string to transition from the first string based on a comparison between the respective voltages of two or more strings of cells. For example, the controller may transition from the first string to the string of cells having the lowest voltage difference among the strings of cells under consideration or available at the time of measurement while discharging only the first string. In some embodiments, the controller may transition to the string of cells having the highest voltage among the strings of cells at the time of measurement. In some embodiments, the controller may transition to the string of cells having the lowest voltage among the strings of cells at the time of measurement. The inventors recognize and understand that transitioning to the closest voltage string, while more computationally expensive, may provide the best chance of minimum delta in many situations, while transitioning to the highest or lowest voltage string may be a less computationally expensive but less accurate alternative.

[0136] In some embodiments, the controller may transition between discharging the first string and discharging the second string when the voltage of the first string drops to a threshold voltage. For example, the threshold voltage may be such that the inrush current resulting from the transition is at most 15 amps or 10 amps, or such that the voltage difference between the first string and the second string may be at most 8% or 5% of the maximum total voltage of the first string or the second string. According to some embodiments, transitioning to another string when the currently discharging string drops to a threshold voltage may reduce voltage fluctuations and improve or ensure performance (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0137] In some embodiments, the controller may overlap in time the discharge of the first string and the second string, similar to the overlap described herein with respect to the set of cells. In some embodiments, the controller may continue to provide power from the string of cells while switching between different strings, similar to the continuous provision of power described herein with respect to the set of cells. The inventors recognize and understand that this overlap in time of the discharge and continuation of power may maintain the power requirements of the load even during the transition between different strings of cells, thereby further improving the cycle life of the cells compared to the prior art. Thus, during such overlap, multiple strings may discharge simultaneously. Furthermore, such overlap may provide a smoother voltage transition than was possible in the prior art.

[0138] In some embodiments, the controller may use the multiplexing switch device to control the duration of the pulse discharge of at least one of the strings of cells based on at least one criterion, For example, the criterion may include a demand of the load (e.g., a power demand of the load) or a voltage difference between at least one of the strings of cells and at least one other of the strings of cells.

[0139] In some embodiments, the criteria may include the load demand, and the controller may use a multiplexing switch device to control the duration of the pulse discharge to be longer when the load demand decreases and shorter when the load demand increases. For example, when the load power demand is low (e.g., less than 50% of rated power), the pulse discharge may be controlled to run for 1 minute, while when the load power demand is high (e.g., 90% or more of rated power), the pulse discharge may be controlled to less than 1 second, or multiple strings may be discharged simultaneously in the case of extremely high demand (such as starting an electric vehicle). According to some embodiments, making the pulse discharge duration inversely proportional to the load demand leads to reduced voltage fluctuations and improved or guaranteed performance (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0140] In some embodiments, a controller such as 114 may use a multiplexing switch device to discharge a first string (e.g., 121) that has a first voltage at the time of measurement while discharging the first string, not yet discharging the second string, and then also discharge a second string from other strings under consideration or available that may have a second voltage closest to the first voltage (either at the same time as the time of measurement or another time within one minute of the previous time). According to some embodiments, transitioning to the closest voltage string reduces voltage fluctuations, leading to improved or ensured performance (e.g., of an electric vehicle) without relying on pre-charge circuits or similar components and their associated cost, complexity, volume, and weight.

[0141] In some embodiments, the criteria may be context-sensitive, such as by considering one or more of the duration of the connection between the load and the set of cells currently connected to the load (which may be at least 0.01 seconds in some embodiments), the delivered discharge capacity in the connection, and the value of a function having one or more parameters. In some embodiments, the criteria may not include the number of previous discharge cycles of the set of cells.

[0142] In some embodiments, the function may have parameters such as any one or more of the following: accumulated capacity over multiple connections between the load and the set of cells, delivered discharge capacity at the connection, current of the set of cells, voltage of the set of cells and / or at least one other set of cells, cutoff discharge voltage of the set of cells, power of the set of cells, energy of the set of cells, number of charge or discharge cycles of the set of cells, impedance of the set of cells, voltage decay rate of the set of cells during connection, temperature of the set of cells, and pressure of the set of cells (e.g., pressure on the cells from a physical enclosure, which may indicate the capacity of the cells, as further described below). According to some embodiments, the delivered discharge capacity at a single connection may be in the range of 0.01% of the nominal capacity to 100% of the set nominal capacity (e.g., 95%).

[0143] In some embodiments, the sensor (e.g., 116) may measure either the criteria and / or the functional parameters. For example, the sensor may include a current sensor that measures the current in amperes of a given set of cells. It should be appreciated that the criteria may be multiple or singular and may relate to the set of cells currently discharging and / or may determine the next set of cells.

[0144] In some embodiments, the controller (e.g., 114) may include one or more processors, which may have any complexity suitable for the application. For example, evaluating the functionality of the criteria in some embodiments may rely on a microprocessor that forms part or all of the controller. Alternatively or additionally, the controller may include analog circuitry and / or logic devices less complex than a processor or microprocessor.

[0145] In some embodiments, the controller may use a multiplexing switch device to selectively discharge and charge a cell or set of cells at different programmable rates. For example, the controller may use a multiplexing switch device to selectively discharge a string, cell, or set of cells at a first rate that is at least two times higher than a second rate at which the set of cells is charged (i.e., discharge twice as fast as the charge). Alternatively or additionally, the first rate of discharge may be at least four times higher than a second rate at which the set of cells is charged (i.e., discharge four times as fast as the charge). The inventors recognize and appreciate that such a ratio of discharge rate to charge rate may improve the performance and cycle life of the cells.

[0146] According to some embodiments, the controller may overlap the discharge of the sets of cells in time. For example, a given cell or set of cells may begin discharging before another cell or set of cells stops discharging. In some embodiments, the controller may continue to provide power from a set of cells while switching between different sets. The inventors recognize and understand that this overlap in time of discharge and continued power may maintain the power requirements of the load even during the transition between different cells or sets of cells, further improving the cycle life of the cells compared to the prior art. Thus, during such overlap, multiple cells may discharge simultaneously. Furthermore, such overlap may provide a smoother voltage transition than was possible in the prior art.

[0147] In some embodiments, the load may be at least one component of a vehicle. The vehicle may be any suitable vehicle adapted for travel on land, sea, and / or air. For example, the vehicle may be a car, a truck, a motorcycle, a boat, a helicopter, an airplane, and / or any other suitable type of vehicle.

[0148] In some embodiments, the electrochemical cells and batteries (e.g., rechargeable batteries) described in this disclosure can be used to power or otherwise incorporated into electric vehicles. As a non-limiting example, stacks of electrochemical cells and / or batteries (e.g., including lithium metal and / or lithium alloy electrochemical cells, phase change materials, and / or multiplexed switching devices) described in this disclosure may be used in some embodiments to provide power to the driveline of an electric vehicle. The vehicle may be any suitable vehicle adapted for travel on land, sea, and / or air. For example, the vehicle may be a car, a truck, a motorcycle, a boat, a helicopter, an airplane, and / or any other suitable type of vehicle.

[0149] Alternatively or additionally, the controller may use a multiplexing switch device (eg, 112) to connect sets of cells to the loads in a topology adopted or required by the loads.

[0150] In some embodiments, the controller may use a multiplexing switch device (e.g., 112) to isolate a single set of cells for discharge while other sets of cells are not discharging. Alternatively or additionally, a single cell may be isolated at a time. For example, the controller may use a multiplexing switch device to isolate a single set of cells or a single cell for discharge while other cells or sets of cells are not discharging. For a given cycle, according to some embodiments (e.g., when sequential discharge is used, but not limited to such embodiments), each cell may be discharged once before any cell is discharged twice.

[0151] With regard to charging, in some embodiments, the controller may use a multiplexing switch device to charge sets of cells and / or cells within a set in parallel, for example, all cells in a block of cells, battery, or multiple batteries may be charged in parallel at one-quarter the discharge rate.

[0152] 1D is a charge-time graph 100D illustrating a charging scheme of an exemplary electrochemical cell management system, according to some embodiments. Graph 100D includes state-of-charge ranges 100D1, 100D2, 100D3, and 100D4.

[0153] In some embodiments, during the charging step, the cell may be charged over a first SOC range 100D1 having a width of at least 2% at a first charge rate, and during the charging step, the cell may be charged over a second state of charge range 100D2 having a width of at least 2% at a second charge rate. Furthermore, during the discharging step, the cell may be discharged over a third state of charge range 100D3 having a width of at least 2% at a first discharge rate that is at least twice the first (100D1) charge rate or the second (100D2) charge rate, and during the discharging step, the cell may be discharged over a fourth state of charge range 100D4 having a width of at least 2% at a second discharge rate that is less than twice the first (100D1) charge rate or the second (100D2) charge rate.

[0154] In some embodiments, during the charging step, the cell may be charged over a first SOC range 100D1 having a width of at least 2% at a first charge rate, and during the charging step, the cell may be charged over a second state of charge range 100D2 having a width of at least 2% at a second charge rate. Furthermore, during the discharging step, the cell may be discharged over a third state of charge range 100D3 having a width of at least 2% at a first discharge rate that is at least twice the first charge rate (at 100D1), and during the discharging step, the cell may be discharged over a fourth state of charge range 100D4 having a width of at least 2% at a second discharge rate that is less than twice the first charge rate (at 100D1).

[0155] In some embodiments, during a charging step, the cell may be charged at a first charge rate over a first SOC range 100D1 having a width of at least 2%, and during a charging step, the cell may be charged at a second charge rate over a second state of charge range 100D2 having a width of at least 2%. Furthermore, during a discharging step, the cell may be discharged at a first discharge rate that is at least twice the second charge rate (at 100D2) over a third state of charge range 100D3 having a width of at least 2%, and during a discharging step, the cell may be discharged at a second discharge rate that is less than twice the second charge rate (at 100D2) over a fourth state of charge range 100D4 having a width of at least 2%.

[0156] In some embodiments, during the charging step, the cell may be charged at a first charge rate over a first SOC range 100D1 having a width of at least 2%, and during the charging step, the cell may be charged at a second charge rate over a second state of charge range 100D2 having a width of at least 2%. Furthermore, during the discharging step, the cell may be discharged at a first discharge rate that is at least twice the first charge rate (at 100D1) over a third state of charge range 100D3 having a width of at least 2%, and during the discharging step, the cell may be discharged at a second discharge rate that is less than twice the second charge rate (at 100D2) over a fourth state of charge range 100D4 having a width of at least 2%.

[0157] In some embodiments, during the charging step, the cell may be charged over a first SOC range 100D1 having a width of at least 2% at a first charge rate, and during the charging step, the cell may be charged over a second state of charge range 100D2 having a width of at least 2% at a second charge rate. Furthermore, during the discharging step, the cell may be discharged over a third state of charge range 100D3 having a width of at least 2% at a first discharge rate that is at least twice the second charge rate (at 100D2), and during the discharging step, the cell may be discharged over a fourth state of charge range 100D4 having a width of at least 2% at a second discharge rate that is less than twice the first charge rate (at 100D1).

[0158] In some embodiments, during the discharge step, the cell may be discharged at a first discharge rate over a third state of charge range 100D3 having a width of at least 2%, and during the discharge step, the cell may be discharged at a second discharge rate over a fourth state of charge range 100D4 having a width of at least 2%. In some embodiments, the first discharge rate (of 100D3) may be at least twice the corresponding charge rate, and the second discharge rate (of 100D4) may be less than twice the corresponding charge rate. In some embodiments, the corresponding charge rate may be a charge rate that spans at least the SOC range of the previous or subsequent charge step. For example, the corresponding charge rate may be a charge rate that spans at least the SOC range of the immediately preceding charge step. In some embodiments, the width of the SOC range is 100%. In some embodiments, the width of the SOC range is at most 90%. In some embodiments, the width of the SOC range is at most 80%. In some embodiments, the width of the SOC range is at most 70%. In some embodiments, the width of the SOC range is at most 60%. In some embodiments, the width of the SOC range is at most 50%. In some embodiments, the width of the SOC range is at most 40%. In some embodiments, the width of the SOC range is at most 30%. In some embodiments, the width of the SOC range is at most 20%. In some embodiments, the width of the SOC range is at most 10%. For example, the SOC range may be a portion or all of 100D1. Alternatively, the SOC range may be a portion or all of 100D2, or any combination of SOC ranges such that the corresponding charge rate is an average of the charge rates over 100D1 and 100D2. In some embodiments, the controller may analyze any number of previous charging steps and perform the discharge in response to the analysis.

[0159] In some embodiments, during the charging step, the cell may be charged over a first SOC range 100D1 having a width of at least 2% at a first charging rate, and during the charging step, the cell may be charged over a second SOC range 100D2 having a width of at least 2% at a second charging rate. In some embodiments, the first charging rate (of 100D1) may be at most 0.5 times the corresponding discharge rate, and the second charging rate (of 100D2) may be greater than 0.5 times the corresponding discharge rate. In some embodiments, the corresponding discharge rate may be a discharge rate that spans at least the SOC range of the previous or subsequent discharge step. For example, the corresponding discharge rate may be a discharge rate that spans at least the SOC range of the immediately preceding discharge step. In some embodiments, the width of the SOC range is at most 40%. In some embodiments, the width of the SOC range is at most 30%. In some embodiments, the width of the SOC range is at most 20%. In some embodiments, the width of the SOC range is at most 10%. For example, the SOC range may be a portion or all of 100D4. Alternatively, the SOC range may be a portion or all of 100D3 or any combination of SOC ranges such that the corresponding discharge rate is the average of the discharge rates across 100D3 and 100D4. In some embodiments, the controller may analyze any number of previous discharge steps and perform charging in response to the analysis.

[0160] 1D shows an example where within certain SOC ranges, the rate ratio is beneficial to cell health, while outside these SOC ranges, the rate ratio is radically different and not necessarily beneficial to cell health. For example, as shown in FIG. 1D, the rate ratio between SOC ranges 100D4 and 100D2 does not meet the rate ratio beneficial to cell health (the discharge and charge rates appear to be nearly symmetric in this example, such as the discharge rate being at least two or four times the average charge rate), whereas the rate ratio between SOC ranges 100D3 and 100D1 does meet such a beneficial rate ratio.

[0161] In some embodiments, these SOC ranges may be in various orders in time. For example, the second SOC range may occur before the first SOC range. Alternatively, the second SOC range may occur after the first SOC range. In some embodiments, the fourth SOC range may occur before the third SOC range. Alternatively, the fourth SOC range may occur after the third state of charge range.

[0162] In some embodiments, the width of the first SOC range 100D1 is at most 40%. In some embodiments, the width of the first SOC range is at most 30%. In some embodiments, the width of the first SOC range is at most 20%. In some embodiments, the width of the first SOC range is at most 10%.

[0163] In some embodiments, the width of the second SOC range is at most 40%. In some embodiments, the width of the second SOC range is at most 30%. In some embodiments, the width of the second SOC range is at most 20%. In some embodiments, the width of the second SOC range is at most 10%.

[0164] In some embodiments, the width of the third SOC range is at most 40%. In some embodiments, the width of the third SOC range is at most 30%. In some embodiments, the width of the third SOC range is at most 20%. In some embodiments, the width of the third SOC range is at most 10%.

[0165] In some embodiments, the width of the fourth SOC range is at most 40%. In some embodiments, the width of the fourth SOC range is at most 30%. In some embodiments, the width of the fourth SOC range is at most 20%. In some embodiments, the width of the fourth SOC range is at most 10%.

[0166] 1E illustrates an exemplary battery management system having a string of cells. In some embodiments, the battery management system may include a collection of strings (e.g., 121) of cells or modules (e.g., 121A-121F) having cells therein. For example, each string of cells may include two or more cells arranged separately or grouped together in a module. In some embodiments, the string of two or more cells may include a multiple of four strings of cells, such as 8 strings, 12 strings, 16 strings, etc.

[0167] In some embodiments, a representative battery management system includes an array of switches (e.g., 181-184) disposed between one or more strings, an input / output bus connected to a load (e.g., 229), and a balance such as a balance rail (e.g., 160), each of which may be connected to a switch. For example, a switch (e.g., 181) may be permanently connected to a string (e.g., 121) and switchably connected to the input / output bus and the balance (e.g., 160). In some embodiments, the switch array may connect or disconnect a cell string from a battery pack input / output bus, which may connect or disconnect a cell string to or from a balance resistor that may share a balance rail with other strings.

[0168] In some embodiments, the balance rail may include a resistor (e.g., 171-174) disposed between the switch and the main balance rail. In some embodiments, the switch may be part of a multiplexed switch arrangement (e.g., 112 shown in FIG. 1A). Additionally, the balance rail may be connected to the multiplexed switch arrangement. In some embodiments, a balance rail may not be included or needed, such as in the system shown in FIG. 17B.

[0169] In some embodiments, a representative battery management system may include fuses (eg, 191-198), for example, at the end of the string opposite the switch.

[0170] In some embodiments, a representative battery management system may include at least one controller (e.g., 114 shown in FIG. 1A) that may use a multiplexing switch device (e.g., 112 shown in FIG. 1A) to selectively discharge strings of cells. Additionally, the controller may use the multiplexing switch device to selectively connect or disconnect the strings of cells to the balance rail.

[0171] In some embodiments, at least one of the strings of cells may have a nominal voltage of at least 60 volts, which may be classified as “high voltage.” Alternatively or additionally, at least one of the strings may have a nominal voltage between 200 volts and 2000 volts.

[0172] In some embodiments, the controller (e.g., 114 shown in FIG. 1A ) may use a multiplexing switch device (e.g., 112 shown in FIG. 1A ) to maintain equal charge states between the strings of cells by adjusting switching times and / or switching states. In some embodiments, the controller may use a multiplexing switch device to keep at least one of the strings of cells connected to the balance rail during use of at least one battery. In some embodiments, all strings of cells may be disconnected when the battery management system is shipped or stored.

[0173] 1F-1J show an exemplary battery management system during an exemplary charging sequence. In some embodiments, the battery management system may include a collection of a set or string (e.g., 121) of cells or modules having cells therein, as described herein. In some embodiments, the exemplary battery management system may include an array of switches (e.g., 181-184) disposed between one or more strings and a balance such as a balance rail (e.g., 160), as described herein, and a switch may be connected to each of these. In some embodiments, the balance rail may include a resistor (e.g., 171-174) disposed between the switch and a main balance rail. In some embodiments, the switch may be part of a multiplexing switch arrangement (e.g., 112 shown in FIG. 1A). Additionally, the balance rail may be connected to the multiplexing switch arrangement.

[0174] FIG. 1F illustrates the battery management system starting in idle mode with all switches (e.g., 181-184) connected to the balance rail (e.g., 160). FIG. 1G illustrates the battery management system at the beginning of charging, where the switches may move from the balance rail to the negative bus in some embodiments. In some embodiments, the energy for charging may enter the negative circuit and charge all cell sets or strings simultaneously. FIG. 1H illustrates the energy charging all cell sets or strings at once. FIG. 1I illustrates the energy charging all cell sets or strings at once at a later stage, such as when the cell sets or strings are each charged to about 25%-50%. FIG. 1J illustrates the battery management system at the end of charging (e.g., the cell sets or strings are charged to about 100%), where in some embodiments the switches may be connected to the balance rail (e.g., the switches may move from the negative bus to the balance rail).

[0175] 1K-1N illustrate an exemplary battery management system during an exemplary discharge sequence. FIG. 1K illustrates an exemplary battery management system where, for example, one cell set or string may be discharged (e.g., via pulse discharge) for 10-30 seconds while the other cell sets or strings are idle. FIG. 1L illustrates an exemplary battery management system where, after discharging the first cell set or string, the next cell set or string in series is discharged for 10-30 seconds while the other cell sets or strings are idle. FIG. 1M illustrates an exemplary battery management system where, for example, the next cell set or string may be discharged for 10-30 seconds while the other cell sets or strings are idle. FIG. 1N illustrates an exemplary battery management system where, for example, the last cell set or string may be discharged for 10-30 seconds while the other cell sets or strings are idle. In some embodiments, discharging may continue until a charge sequence is required, which may occur at various charge levels.

[0176] 2A is an exemplary high-level method 200A for managing an electrochemical cell according to some embodiments. The electrochemical cell may be, for example, the electrochemical cell 121A of exemplary FIG. 1A. Improvements to the exemplary method 200A are described in detail in the following paragraphs.

[0177] In some embodiments, the exemplary method 200A may include a refinement 2300A in which the electrochemical cell is controlled such that it may be charged over a first state of charge range having a width of at least 20%.

[0178] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the first state of charge range may be uninterrupted by a discharging step.

[0179] In some embodiments, the first state of charge range includes a single charge step, hi some embodiments, the first state of charge range is bounded by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) discharge steps performed over a state of charge range having an amplitude of at least 5%.

[0180] In some embodiments, the charge rate in the first state of charge range is controlled based on at least one monitored characteristic of the cell including cell impedance and / or cell resistance.

[0181] In some embodiments, improvement 2300A may include improvement 2302A, where an average charge rate in a first portion of the first state of charge range may be lower than an average charge rate in a second portion of the first state of charge range. In some embodiments, improvement 2300A may include improvement 2304A, where the first portion may span at least 2% of the first state of charge range and the second portion may span at least 2% of the first state of charge range. In some embodiments, the first portion may span at most 98% of the first state of charge range and the second portion may span at most 98% of the first state of charge range.

[0182] In some embodiments, the first portion may occur before the second portion, e.g., charging to a first portion of the first state of charge range may occur before charging to a second portion of the first state of charge range.

[0183] In some embodiments, the exemplary method 200A can then proceed to refinement 2500A, in which the electrochemical cell is controlled to be discharged over a second state of charge range having a width of at least 2% and then discharged over a third state of charge range having a width of at least 2%. In some embodiments, the second state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the third state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the second state of charge range may be higher than the average discharge rate in the third state of charge range. In some embodiments, the average discharge rate in the second state of charge range may be at least twice the average discharge rate in the third state of charge range.

[0184] In some embodiments, the third state of charge range and the fourth state of charge range are part of the same discharge step, hi some embodiments, the third state of charge range and the fourth state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0185] In some embodiments, the exemplary method 200A may then proceed to refinement 2600A, where the electrochemical cell may be controlled to be discharged over a fourth state of charge range having a width of at least 2%. In some embodiments, the fourth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the third state of charge range may be higher than the average discharge rate in the fourth state of charge range.

[0186] For example, the electrochemical cell may be controlled to be discharged over a second state of charge range having a width of at least 2%, then discharged over a third state of charge range having a width of at least 2%, then discharged over a fourth state of charge range having a width of at least 2%. In some embodiments, the second state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the third state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the fourth state of charge range may have a width of at most 90%, at most 50%, at most 30%, or at most 20%.

[0187] In some embodiments, the cell is discharged over a third state of charge range after the cell is charged through the second state of charge range.

[0188] In some embodiments, the second state of charge range and the third state of charge range are part of the same discharge step, hi some embodiments, the second state of charge range and the third state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0189] In some embodiments, the third state of charge range and the fourth state of charge range are part of the same discharge step, hi some embodiments, the third state of charge range and the fourth state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0190] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300A, 2500A, and / or 2600A based on a time interval as set by the user. For example, the user may select the time for which they want the battery pack to charge (e.g., the time for which they want charging to stop for use again, such as at a charging station for an electric vehicle), and the battery management system may change the algorithm accordingly. One example is when the user selects a 15-minute charge. In such an example, the controller may charge at a constantly (or periodically) increasing charge rate to span the selected 15 minutes. The inventors recognize and appreciate that controlling the charge and / or discharge as described herein based on a selected time interval may provide the user with the experience and performance they require while providing the cells with conditions favorable to cycle life.

[0191] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300A, 2500A, and / or 2600A based on a time of day, such as set by a user or determined by a controller. For example, a user may select a time when they want the battery pack to be as close to full charge as possible (e.g., a time when they want charging to stop for use again, such as at a charging station for an electric vehicle), and the battery management system may change the algorithm accordingly. One example is when a user selects 8:00 a.m. as the start time for their commute. In such an example, the controller may charge at a constantly (or periodically) increasing charge rate to cover at least a portion of the time remaining until the set time. In some embodiments, the controller may learn the user's behavior and set the time itself based on the collection of data about the user and other users. The inventors recognize and appreciate that controlling charging and / or discharging as described herein based on a time of day may provide the user with the experience and performance they require while providing conditions for the cells that are favorable for cycle life.

[0192] In some embodiments, the controller may determine a cell's state of charge (e.g., for use in determining any of the above states of charge and state of charge ranges) based on the cell's voltage. For example, certain voltages correspond to certain states of charge, depending on a number of factors that may be known to the controller.

[0193] According to some embodiments, a controller (eg, controller 114 of FIG. 1A) may perform improvements 2300A, 2500A, and / or 2600A.

[0194] Some example embodiments are shown in FIG. 2D and its description below.

[0195] 2B is an exemplary high-level method 200B for managing an electrochemical cell according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 200B are described in detail in the following paragraphs.

[0196] In some embodiments, the representative method 200B may include an improvement 2300B in which the electrochemical cell is controlled to be charged over a first state of charge range having a width of at least 2% and at most 90%, or at most 50%, or at most 30%, or at most 20%.

[0197] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the charge rate in the first state of charge range is controlled based on at least one monitored characteristic of the cell including cell impedance and / or cell resistance.

[0198] In some embodiments, the representative process 200B can then proceed to refinement 2400B, where the electrochemical cell is controlled such that the cell may be charged over a second state of charge range. In some embodiments, the average charge rate in the first state of charge range can be at most 0.5 times the average charge rate in the second state of charge range. In some embodiments, the average charge rate in the first state of charge range can be at most 0.25 times the average charge rate in the second state of charge range.

[0199] In some embodiments, the first state of charge range and the second state of charge range are part of the same charging step. In some embodiments, the first state of charge range and the second state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) discharge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0200] In some embodiments, the representative method 200B can then proceed to improvement 2500B, where the electrochemical cell is controlled such that it may be discharged over a third state of charge range having a width of at least 2% and then discharged over a fourth state of charge range having a width of at least 2%. In some embodiments, the third state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the fourth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the third state of charge range may be higher than the average discharge rate in the fourth state of charge range. In some embodiments, the average discharge rate in the third state of charge range may be at least twice the average discharge rate in the fourth state of charge range.

[0201] In some embodiments, the third state of charge range and the fourth state of charge range are part of the same discharge step, hi some embodiments, the third state of charge range and the fourth state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0202] In some embodiments, the exemplary method 200B may then proceed to improvement 2600B, where the electrochemical cell is controlled to be discharged over a fifth state of charge range having a width of at least 2%. In some embodiments, the fifth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the second state of charge range may be higher than the average discharge rate in the third state of charge range. In some embodiments, the average discharge rate in the third state of charge range may be higher than the average discharge rate in the fourth state of charge range. In some embodiments, the average discharge rate in the fourth state of charge range may be higher than the average discharge rate in the fifth state of charge range.

[0203] In some embodiments, the fourth state of charge range and the fifth state of charge range are part of the same discharge step, hi some embodiments, the fourth state of charge range and the fifth state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0204] In some embodiments, the cell may be charged through a second state of charge range and then discharged through a third state of charge range.

[0205] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300B, 21500B, 2500B, and / or 2600B based on a time interval, such as one set by a user. For example, the user may select the time they want the battery pack to charge (e.g., the time they want charging to stop for use again, such as at a charging station for an electric vehicle), and the battery management system may change the algorithm accordingly. One example is when the user selects a 15-minute charge. In such an example, the controller may charge at a constantly (or periodically) increasing charge rate to span the selected 15 minutes. The inventors recognize and appreciate that controlling the charge and / or discharge as described herein based on a selected time interval may provide the user with the experience and performance they require while providing the cells with conditions favorable to cycle life.

[0206] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300B, 21500B, 2500B, and / or 2600B based on a time of day, such as set by a user or determined by a controller. For example, a user may select a time when they want the battery pack to be as close to full charge as possible (e.g., a time when they want to stop charging for use again at a charging station for an electric vehicle, etc.), and the battery management system may change the algorithm accordingly. One example is when a user selects 8:00 a.m. as the start time for their commute. In such an example, the controller may charge at an increasing charge rate all the time (or periodically) to cover at least a portion of the time remaining until the set time. In some embodiments, the controller may learn the user's behavior and set the time itself based on the collection of data about the user and other users. The inventors recognize and appreciate that controlling the charge and / or discharge as described herein based on the time of day may provide the cells with conditions favorable to cycle life while providing the user with the experience and performance they require.

[0207] In some embodiments, the controller may determine a cell's state of charge (e.g., for use in determining any of the above states of charge and state of charge ranges) based on the cell's voltage. For example, certain voltages correspond to certain states of charge, depending on a number of factors that may be known to the controller.

[0208] According to some embodiments, a controller (eg, controller 114 of FIG. 1A) may perform improvements 2300B, 21500B, 2500B, and / or 2600B.

[0209] Examples of some embodiments are provided in FIG. 2D and its description below.

[0210] 2C is an exemplary high-level method 200C for managing an electrochemical cell according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 200C are described in detail in the following paragraphs.

[0211] In some embodiments, the representative method 200C may include a refinement 2300C in which the electrochemical cell is controlled to be charged over a first state of charge range having a width of at least 2% and at most 40%, or at most 50%, or at most 30%, or at most 20%.

[0212] In some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the first state of charge range may be uninterrupted by a discharge step. In some embodiments, the charge rate in the first state of charge range is controlled based on at least one monitored characteristic of the cell including cell impedance and / or cell resistance.

[0213] In some embodiments, the exemplary method 200C may then proceed to refinement 21500C, where the electrochemical cell is controlled to be charged over a second state of charge range having a width of at least 2%. In some embodiments, the second state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the charge rate in the first state of charge range may be lower than the average charge rate in the second state of charge range. In some embodiments, the charge rate in the first state of charge range may be an average charge rate. In some embodiments, the charge rate in the first state of charge range may be a constant charge rate.

[0214] In some embodiments, the first state of charge range and the second state of charge range are part of the same charging step. In some embodiments, the first state of charge range and the second state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) discharge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0215] In some embodiments, the exemplary method 200C may then proceed to refinement 2450C, where the electrochemical cell is controlled to be charged over a third state of charge range having a width of at least 2%. In some embodiments, the third state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average charge rate in the second state of charge range may be lower than the average charge rate in the third state of charge range.

[0216] In some embodiments, the second state of charge range and the third state of charge range are part of the same charging step. In some embodiments, the second state of charge range and the third state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) discharge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0217] In some embodiments, the exemplary method 200C may then proceed to improvement 2500C, where the electrochemical cell is controlled to be discharged over a fourth state of charge range having a width of at least 2% and then discharged over a fifth state of charge range having a width of at least 2%. In some embodiments, the fourth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the fifth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the fourth state of charge range may be higher than the average discharge rate in the fifth state of charge range. In some embodiments, the average discharge rate in the fourth state of charge range may be at least twice the average discharge rate in the fifth state of charge range.

[0218] In some embodiments, the fourth state of charge range and the fifth state of charge range are part of the same discharge step, hi some embodiments, the fourth state of charge range and the fifth state of charge range are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0219] In some embodiments, the exemplary method 200C may then proceed to refinement 2600C, where the electrochemical cell is controlled to be discharged over a sixth state of charge range having a width of at least 2%. In some embodiments, the sixth state of charge range may have a width of at most 90%, or at most 50%, or at most 30%, or at most 20%. In some embodiments, the average discharge rate in the fifth state of charge range may be higher than the average discharge rate in the sixth state of charge range.

[0220] In some embodiments, the fifth and sixth state of charge ranges are part of the same discharge step, hi some embodiments, the fifth and sixth state of charge ranges are separated by 25 or less (or 15 or less, 10 or less, 5 or less, 3 or less, 2 or less, or 1 or less) charge steps carried out over state of charge ranges having an amplitude of at least 5%.

[0221] In some embodiments, the cell may be discharged over a fourth state of charge range after the cell is charged in the third state of charge range.

[0222] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300C, 21500C, 2450C, 2500C, and / or 2600C based on a time interval, such as one set by a user. For example, the user may select a time to charge the battery pack (e.g., when to stop charging for use again, such as at a charging station for an electric vehicle), and the battery management system may change the algorithm accordingly. One example is when a user selects a 15-minute charge. In such an example, the controller may charge at a constantly (or periodically) increasing charge rate to span the selected 15 minutes. The inventors recognize and appreciate that controlling the charge and / or discharge as described herein based on a selected time interval may provide the user with the experience and performance they require while providing the cells with conditions favorable to cycle life.

[0223] In some embodiments, the cells are charged or discharged (e.g., charged over a first state of charge range) as described in improvements 2300C, 21500C, 2450C, 2500C, and / or 2600C based on a time of day, such as set by a user or determined by a controller. For example, a user may select a time when they want the battery pack to be as close to full charge as possible (e.g., when they want to stop charging for use again at a charging station for an electric vehicle, etc.), and the battery management system may change the algorithm accordingly. One example is when a user selects 8:00 a.m. as the start time for their commute. In such an example, the controller may charge at an increasing charge rate all the time (or periodically) to cover at least a portion of the time remaining until the set time. In some embodiments, the controller may learn the user's behavior and set the time itself based on the collection of data about the user and other users. The inventors recognize and appreciate that controlling the charging and / or discharging as described herein based on the time of day may provide the user with the experience and performance they require while providing the cells with conditions favorable to cycle life.

[0224] In some embodiments, the controller may determine a cell's state of charge (e.g., for use in determining any of the above states of charge and state of charge ranges) based on the cell's voltage. For example, certain voltages correspond to certain states of charge, depending on a number of factors known to the controller.

[0225] According to some embodiments, a controller (eg, controller 114 of FIG. 1A) may perform improvements 2300C, 21500C, 2450C, 2500C, and / or 2600C.

[0226] Some example embodiments are provided in FIG. 2D and its description below. FIG. 2D is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (eg, electrochemical cell 121A) in conjunction with the methods described in FIGS. 2A-2C.

[0227] An example of a first state of charge range of FIG. 2A is shown in FIG. 2D from points 201A to 201B2. An example of a first portion of such a range of FIG. 2A is shown in FIG. 2D from points 201A to 201B1. An example of a second portion of such a range of FIG. 2A is shown in FIG. 2D from points 201B1 to 201B2. As FIG. 2D shows, the cell is charged from 201A to 201B1, and then charged at a faster rate from 201B1 to 201C, beginning another cycle of discharge and charge. In this example, the first state of charge range of 201A to 201B2 is about 0% to 20% and has a width of 20%. In this example, the first portion of the first state of charge range of 201A to 201B1 is about 0% to 10% and has a width of 10%. In this example, the second portion of the first state of charge range from 201B1 to 201B2 is from about 10% to 20%, having a width of 10%.

[0228] An example of the second state of charge range of FIG. 2A is shown at points 201C to 201D in FIG. 2D. An example of the third state of charge range of FIG. 2A is shown at points 201D to 201E in FIG. 2D. An example of the fourth state of charge range of FIG. 2A is shown at points 201E to 201F in FIG. 2D. As FIG. 2D shows, the cell is discharged from 201C to 201D, then discharged at a slower rate from 201D to 201E, then discharged at an even slower rate from 201D to 201E, and another charging step begins after 201F. In this example, the second state of charge range from 201C to 201D is about 100% to 20%, with a width of 80%. In this example, the third state of charge range from 201D to 201E is about 20% to 5%, with a width of 15%. In this example, a fourth state of charge range from 201E to 201F is from about 5% to 0%, a width of 5%.

[0229] An example of the first state of charge range of FIG. 2B is shown at points 201A to 201B1 in FIG. 2D. An example of the second state of charge range of FIG. 2B is shown at points 201B3 to 201C in FIG. 2D. As shown in FIG. 2D, the cell is charged from 201A to 201B1, then charged at a faster rate from 201B1 to 201B3, then charged at an even faster rate from 201B3 to 201C before another discharge and charge cycle begins. In this example, the first state of charge range from 201A to 201B1 is about 0% to 10%, with a width of 10%. In this example, the second state of charge range from 201B3 to 201C is about 40% to 100%, with a width of 60%.

[0230] An example of the third state of charge range of FIG. 2B is shown at points 201C to 201D in FIG. 2D. An example of the fourth state of charge range of FIG. 2B is shown at points 201D to 201E in FIG. 2D. An example of the fifth state of charge range of FIG. 2B is shown at points 201E to 201F in FIG. 2D. As shown in FIG. 2D, the cell is discharged from 201C to 201D, then discharged at a slower rate from 201D to 201E, then discharged at an even slower rate from 201D to 201E, then discharged at an even slower rate from 201E to 201F, and then another charging step is started after 201F. In this example, the third state of charge range from 201C to 201D is about 100% to 20%, with a width of 80%. In this example, a fourth state of charge range from 201D to 201E is about 20% to 5%, with a width of 15%. In this example, a fifth state of charge range from 201E to 201F is about 5% to 0%, with a width of 5%.

[0231] An example of the first state of charge range of FIG. 2C is shown at points 201A to 201B1 in FIG. 2D. An example of the second state of charge range of FIG. 2C is shown at points 201B1 to 201B3 in FIG. 2D. An example of the third state of charge range of FIG. 2C is shown at points 201B3 to 201C in FIG. 2D. As shown in FIG. 2D, the cell is charged from 201A to 201B1, then charged at a faster rate from 201B1 to 201B3, then charged at an even faster rate from 201B3 to 201C before another discharge and charge cycle begins. In this example, the first state of charge range from 201A to 201B1 is about 0% to 10%, with a width of 10%. In this example, the second state of charge range from 201B1 to 201B3 is about 10% to 40%, with a width of 30%. In this example, the third state of charge range from 201B3 to 201C is from about 40% to 100%, with a width of 60%.

[0232] An example of the fourth state of charge range of FIG. 2C is shown at points 201C to 201D in FIG. 2D. An example of the fifth state of charge range of FIG. 2C is shown at points 201D to 201E in FIG. 2D. An example of the sixth state of charge range of FIG. 2C is shown at points 201E to 201F in FIG. 2D. As shown in FIG. 2D, the cell is discharged from 201C to 201D, then discharged at a slower rate from 201D to 201E, then discharged at an even slower rate from 201D to 201E, then discharged at an even slower rate from 201E to 201F, and then another charging step is started after 201F. In this example, the fourth state of charge range from 201C to 201D is about 100% to 20%, with a width of 80%. In this example, the fifth state of charge range from 201D to 201E is about 20% to 5%, a range of 15%. In this example, the sixth state of charge range from 201E to 201F is about 5% to 0%, a range of 5%.

[0233] In some embodiments, the width of any of the aforementioned state of charge ranges is at most 50%. In some embodiments, the width is at most 40%. In some embodiments, the width is at most 30%. In some embodiments, the width is at most 20%. In some embodiments, the width is at most 10%.

[0234] In some embodiments, the aforementioned range of state of charge is at least 5%. In some embodiments, the range is at least 10%.

[0235] In some embodiments, the aforementioned state of charge ranges have a minimum state of charge of 5% or less. The inventors recognize and appreciate that states of charge having a minimum state of charge of a certain percentage or less, e.g., 5%, may be particularly effective in providing the improvements described herein.

[0236] In some embodiments, the rate in any of the aforementioned state of charge ranges includes an average rate. For example, the rate may be an average of multiple constant rates, an average of a modulated rate, or some combination of both or an average of other suitable rates. In some embodiments, the rate in the state of charge ranges includes a constant rate.

[0237] In some embodiments, the discharge or charge rate may vary, so long as it is at least twice (or four times) the control rate (e.g., the rate being compared) over the entire state of charge range. Alternatively, the rate may be constant. Alternatively, the rate may be at least twice (or four times) less than the control rate, so long as the rate is, on average, at least twice (or four times) the control rate.

[0238] In some embodiments, the rate at which the aforementioned state of charge ranges are performed is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance. For example, if the impedance and / or cell resistance are measured and meet a threshold condition or value, the controller may initiate, terminate, or modify any of the aforementioned charge and discharge profiles.

[0239] 3A is an exemplary high-level method 300A for managing an electrochemical cell according to some embodiments. The electrochemical cell may be, for example, the electrochemical cell 121A of exemplary FIG. 1A. Improvements to the exemplary method 300A are described in detail in the following paragraphs.

[0240] In some embodiments, the exemplary method 300A may include an improvement 320 that can analyze the cycle history of the electrochemical cell. In some embodiments, the exemplary method 300A may include an improvement 330 that controls the electrochemical cell to discharge the cell to meet a criterion if none of the most recent cycles meet a criterion for a number of most recent cycles in the cycle history. The criterion may include, for example, that the cell is discharged at a discharge rate that is at least twice the average charge rate of any of the most recent cycles over a state of charge range that is at least 2% wide and at most 60% wide. The most recent number of cycles may be, for example, at least 5 cycles. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform the improvement 320 and / or 330.

[0241] In some embodiments, the exemplary method 300A may initiate optional improvements 310, including monitoring a characteristic of the cell. The improvements 330 may further include improvement 331, where the discharge rate in the state of charge range may be at least four times the average charge rate of any cycle in the most recent cycles. The improvements 330 may further include improvement 332, where the discharge rate in the state of charge range may be controlled based on at least one monitored characteristic of the cell, such as cell impedance and / or cell resistance.

[0242] In some embodiments, the width of the state of charge range is at most 50%. In some embodiments, the width is at most 40%. In some embodiments, the width is at most 30%. In some embodiments, the width is at most 20%. In some embodiments, the width is at most 10%.

[0243] In some embodiments, the width of the state of charge range is at least 5%. In some embodiments, the width is at least 10%.

[0244] In some embodiments, the state of charge range has a minimum state of charge of 5% or less. The inventors recognize and appreciate that states of charge having a minimum state of charge of a certain percentage or less, e.g., 5%, may be particularly effective in providing the improvements described herein.

[0245] In some embodiments, the discharge rate in the state of charge range includes an average discharge rate. For example, the discharge rate may be an average of multiple constant rates, an average of a modulated rate, or some combination of both or other suitable rates. In some embodiments, the discharge rate in the state of charge range includes a constant discharge rate.

[0246] In some embodiments, the discharge or charge rate may vary, so long as it is at least twice (or four times) the control rate (e.g., the rate being compared) over the entire state-of-charge range. Alternatively, the rate may be constant. Alternatively, the rate may be at least twice (or four times) lower than the control rate, so long as the rate is, on average, at least twice (or four times) the control rate.

[0247] In some embodiments, the discharge rate in the state of charge range is at least four times the average charge rate of any cycle within the most recent cycles.

[0248] In some embodiments, the discharge rate through the state of charge range is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance.

[0249] In some embodiments, the discharge rate in the state of charge range is at least four times the average charge rate of any cycle within the most recent cycles.

[0250] FIG. 3B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 3A. An example of the cycle history of FIG. 3A is shown in FIG. 3B over the change in state of charge from time 301A to 301B. An example of the state of charge range of FIG. 3A is shown at points 302A to 302B in FIG. 3B. As shown in FIG. 3B, the cell is discharged from 301A to 302A, and then discharged faster from 302A to 302B. In this example, the state of charge range from 302A to 302B is about 10% to 0%, with a width of 10%.

[0251] As shown in Figure 3A, the cycle history may be analyzed. If no cycles in the most recent cycles meet the criteria, the cell may be discharged to meet the criteria. The range between 302A and 302B shows one example of meeting the criteria of a cell being discharged at a discharge rate at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range having a width of at least 2% and at most 60%.

[0252] 3C is an exemplary high-level method 300C for managing an electrochemical cell according to some embodiments. The electrochemical cell may be, for example, the electrochemical cell 121A of exemplary FIG. 1A. Improvements to the exemplary method 300C are described in detail in the following paragraphs.

[0253] In some embodiments, the exemplary method 300C may include an improvement 320 to analyze the cycle history of the electrochemical cell. In some embodiments, the exemplary method 300C may include an improvement 330C to control the electrochemical cell to discharge the cell to meet a criterion if none of the most recent cycles meet the criterion for a number of most recent cycles in the cycle history. The criterion may include, for example, the cell being discharged at a discharge rate that is at least twice the average discharge rate of any of the most recent cycles over a state of charge range having a width of at least 2% and at most 60% (or at most 50%, or at most 30%, or at most 20%), and the discharge rate is at most 4 times the maximum recommended continuous discharge rate. In some embodiments, the discharge rate may be within 50-200% of the manufacturer's maximum recommended continuous discharge rate. The present inventors have recognized and understood that manufacturers set such recommended charge and discharge rates primarily based on the battery's capabilities after various performance tests. For example, if a battery can handle a 3C discharge but 4C is insufficient, then a continuous discharge of at most 3C is recommended. The shortfall may be based on performance (e.g. very little capacity gained at 4C) or future performance expectations (e.g. after one or repeated cycles at 4C the cell's performance / capacity degrades rapidly even at lower rates), or more importantly safety, e.g. the cell produces unacceptable amounts of gas after a 4C discharge or its safety profile is compromised after fast charging (short circuits or thermal runaway are more likely to occur). The recommended charge and discharge rates are intended to maximize cycle life, performance, safety and to ensure users do not abuse the cells.

[0254] The most recent number of cycles may be, for example, at least 5 cycles. Alternatively, the most recent number of cycles may be, for example, at least 2 cycles. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform improvements 320 and / or 330C.

[0255] In some embodiments, exemplary method 300C may begin with optional improvement 310, including monitoring a characteristic of the cell. Improvement 330C may further include improvement 331, where the discharge rate in the state of charge range may be at least four times the average discharge rate of any cycle in the most recent cycles. Improvement 330C may further include improvement 332, where the discharge rate in the state of charge range may be controlled based on at least one monitored characteristic of the cell, such as cell impedance and / or cell resistance.

[0256] In some embodiments, the width of the state of charge range is at most 50%. In some embodiments, the width is at most 40%. In some embodiments, the width is at most 30%. In some embodiments, the width is at most 20%. In some embodiments, the width is at most 10%.

[0257] In some embodiments, the range of states of charge is at least 5%. In some embodiments, the range is at least 10%.

[0258] In some embodiments, the state of charge range has a minimum state of charge of 5% or less. The inventors have recognized and appreciated that a state of charge having a minimum state of charge of a certain percentage or less, e.g., 5%, may be particularly effective in providing the improvements described herein.

[0259] In some embodiments, the discharge rate in the state of charge range includes an average discharge rate, hi some embodiments, the discharge rate in the state of charge range is at least four times the average charge rate of any cycle in the most recent cycles.

[0260] In some embodiments, the discharge rate in the state of charge range comprises a constant discharge rate.

[0261] In some embodiments, the discharge rate in the state of charge range is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance, hi some embodiments, the discharge rate in the state of charge range is at least four times the average charge rate of any cycle in the most recent cycles.

[0262] FIG. 3D is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 3C. An example of the cycle history of FIG. 3C is shown in FIG. 3D over the change in state of charge from time 301A to 301B. An example of the state of charge range of FIG. 3C is shown at points 302A to 302B in FIG. 3D. As shown in FIG. 3D, the cell is discharged from 301A to 302A, and then discharged more quickly from 302A to 302B. In this example, the state of charge range from 302A to 302B is approximately 10% to 0%, with a width of 10%.

[0263] The cycle history may be analyzed as shown in FIG. 3C. If none of the most recent number of cycles meets the criteria, the cell may be discharged to meet the criteria. The range defined between elements 302A and 302B shows one example of meeting the criteria of a cell being discharged at a discharge rate at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range having a width of at least 2% and at most 60%, and the discharge rate is at most 4 times the maximum recommended continuous discharge rate.

[0264] 4A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 400A are described in detail in the following paragraphs.

[0265] In some embodiments, the exemplary method 400A may include an improvement 1520, where a cycle history of the electrochemical cell may be analyzed. In some embodiments, the exemplary method 400A may include an improvement 1530, where the electrochemical cell is controlled to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a number of most recent cycles in the cycle history. The number of most recent cycles may be, for example, at least five cycles. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform the improvement 1520 and / or 1530.

[0266] In some embodiments, the exemplary method 400A may include an optional refinement 410 that includes monitoring a characteristic of the cell. In refinement 435, the charge rate in the state of charge range may be controlled based on at least one monitored characteristic of the cell, as described herein. The exemplary method 400A may also include an optional refinement 1536, where the charge rate in the state of charge range is at most 0.25 times the average discharge rate of any cycle in the most recent cycle.

[0267] In some embodiments, the range is at most 50%. In some embodiments, the range is at most 40%. In some embodiments, the range is at most 30%. In some embodiments, the range is at most 20%. In some embodiments, the range is at most 10%. In some embodiments, the state of charge range has a minimum state of charge of 5% or less.

[0268] In some embodiments, the range is at least 5%. In some embodiments, the range is at least 10%.

[0269] In some embodiments, the charge rate over the range of state of charge comprises an average charge rate, hi some embodiments, the charge rate over the range of state of charge comprises a constant charge rate.

[0270] According to some embodiments, the charge rate in the state of charge range is at most 0.25 times the average discharge rate of any cycle within the most recent cycles.

[0271] In some examples, the charge rate through the state of charge range is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance.

[0272] FIG. 4B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 4A. An example of the cycle history of FIG. 4A is shown in FIG. 4B over the change in state of charge shown from time 301A to 301B. An example of the state of charge range of FIG. 4A is shown at points 402A to 402B in FIG. 4B. As shown in FIG. 4B, the cell is discharged at multiple rates from 301A to 402A to about 100% to 0% state of charge, then discharged from 402A to 402B to about 0% to 10% state of charge, and then charged at a higher rate. In this example, the state of charge range from 402A to 402B is about 0% to 10%, with a width of 10%.

[0273] As shown in Figure 4A, the cycle history (e.g., the period between 301A and 301B) may be analyzed. If none of the most recent number of cycles meets the criteria, the cell may be charged to meet the criteria. The range defined between elements 402A and 402B illustrates one example of a period that meets the criteria of a cell being charged at a charge rate of at most 0.5 times the average discharge rate of any cycle in the most recent cycles over a state of charge range having a width of at least 2% and at most 60%.

[0274] 5A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 500A are described in detail in the following paragraphs.

[0275] In some embodiments, the exemplary method 500A may include an improvement 520, where the cycling history of the electrochemical cell may be analyzed. In some embodiments, the exemplary method 500A may include an improvement 530, where the electrochemical cell is controlled such that if a threshold state of charge is reached during discharging, the discharge rate of the cell is increased to at least two times the average charge rate of at least one cycle in the cycling history.

[0276] In some embodiments, in the improvement 530, the electrochemical cell is controlled such that if a threshold state of charge is reached during discharge, the discharge rate of the cell is increased to at least twice the average charge rate of at least a portion of at least one cycle of the cycle history, in some embodiments, the portion includes a first state of charge range having a width of at least 2% and at most 60%.

[0277] According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform improvements 520 and / or 530. In some embodiments, the threshold state of charge has a value of 60% or less. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0278] In some embodiments, the exemplary method 500A may include an optional improvement 510 that includes monitoring a characteristic of the cell. In improvement 535, the discharge rate may be controlled based on at least one monitored characteristic of the cell. In some embodiments, the monitored characteristic may include cell impedance and / or cell resistance as described herein. Additionally, the exemplary method 500A may include an optional improvement 540 that may set and execute a future discharge schedule. For example, the future discharge schedule may be set and executed such that the discharge rate is increased to at least twice the average charge rate of at least one cycle of the cycle history for at least 5 cycles and less than 50 cycles out of every 100 cycles. Alternatively or additionally, the future discharge schedule may be set and executed such that the discharge rate is increased to at least twice the average charge rate of at least a portion of at least one cycle of the cycle history for at least 5 cycles and less than 50 cycles out of every 100 cycles.

[0279] In some embodiments, the threshold state of charge has a value of 50% or less. In some embodiments, the threshold state of charge has a value of 40% or less. In some embodiments, the threshold state of charge has a value of 30% or less. In some embodiments, the threshold state of charge has a value of 20% or less. In some embodiments, the threshold state of charge has a value of 10% or less.

[0280] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 40%. According to some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the width of the first state of charge range is at most 10%.

[0281] In some embodiments, the width of the first state of charge range is at least 5%. In some embodiments, the width of the first state of charge range is at least 10%.

[0282] In some embodiments, the increased discharge rate comprises an average discharge rate, hi some embodiments, the increased discharge rate comprises a constant discharge rate.

[0283] In some embodiments, the charge rate in the first state of charge range comprises an average charge rate. In some embodiments, the charge rate in the first state of charge range comprises a constant charge rate.

[0284] According to some embodiments, the increased discharge rate is at least four times the average charge rate of at least one cycle in the cycling history.

[0285] According to some embodiments, the increased discharge rate is at least four times the average charge rate for at least a portion of at least one cycle in the cycling history.

[0286] In some examples, the increased discharge rate is controlled based on at least one monitored characteristic of the cell, such as those described herein.

[0287] In some examples, a future discharge schedule is established and executed such that for at least 5 cycles and less than 50 cycles out of every 100 cycles, the discharge rate is increased to at least twice the average charge rate of at least one cycle in the cycle history.

[0288] In some examples, a future discharge schedule is set and executed such that for at least 5 and less than 50 out of every 100 cycles, the discharge rate is increased to at least twice the average charge rate for at least a portion of at least one cycle in the cycle history.

[0289] In some embodiments, at least one cycle in the cycle history includes the most recent cycle.

[0290] FIG. 5B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 5A. An example of the cycle history of FIG. 5A is shown in FIG. 5B over the change in state of charge shown from time 301A to 301B. An example of a cycle of the cycle history of FIG. 5A is shown in part (charging) 502A to 502B of FIG. 5B. An example of a threshold state of charge of FIG. 5A is shown at point 301B of FIG. 5B. As shown in FIG. 5B, the cell is discharged from 301A to 502A at multiple rates from about 100% to 0% state of charge, then charged from 502A to 502B at multiple rates from about 0% to 100% state of charge, discharged to 301B, and then discharged at a higher rate to point 503.

[0291] For example, the cycle history may be analyzed as shown in FIG. 5A. In the example shown in FIG. 5B, during discharge at time 301B, a threshold state of charge is reached, in this case 10%. Thus, the discharge rate of the cell increases to at least twice the average charge rate of at least one cycle in the cycle history. For example, the average charge rate of at least one cycle in the cycle history can span the period between times 502A and 502B. Alternatively or additionally, the average charge rate of at least one cycle in the cycle history can span any portion of the period between times 502A and 502B. The period between 301B and 503 indicates an increase in the discharge rate to at least twice the average charge rate of the charge represented between times 502A and 502B.

[0292] 6A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1. Improvements to the exemplary method 600A are described in detail in the following paragraphs.

[0293] In some embodiments, the exemplary method 600A may include an improvement 620, where the electrochemical cell is controlled such that a charging step is terminated at a terminal state of charge, a discharge is initiated, and during the initiated discharge the cell is discharged at a discharge rate that is at least twice the average charge rate of the terminated charging step over a state of charge range having a width of at least 1%, which may be referred to as a conditioning cycle or "mini-cycle."

[0294] In some embodiments, in improvement 620, the electrochemical cell is controlled such that the charging step is terminated and discharging is initiated at a termination state of charge, and the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of the terminated charging step over a state of charge range having a width of at least 1% during the initiated discharge, in some embodiments, the portion includes a first state of charge range having a width of at least 2% and at most 60%.

[0295] According to some embodiments, a conditioning cycle may be performed at the beginning of any or all charging steps. For example, the cell may be controlled to be charged to a 10% state of charge (or charged to 10% above the current state of charge) and then discharged at 2 or 4 times the charge rate to a state of charge near 0% (or discharged to 10% below the state of charge after charging). According to some embodiments, a conditioning cycle may be performed between discharging and charging the cell. In some embodiments of the techniques and methods provided herein, the discharge rate and / or charge rate may be predetermined. According to some embodiments, a constant current may be used, for example, between discharging and charging the cell. According to some embodiments, a modulated current may be used. The inventors have recognized and understood that these conditioning or "mini" cycles may allow for a predetermined discharge and charge rate, whether constant or modulated.

[0296] According to some embodiments, a conditioning cycle may be performed as part of an otherwise typical discharge process that does not meet the target ratio by itself. For example, the cell may be controlled so that the "bottom" of the discharge process is four times faster than the start of the next charge process (such as may be performed when feeding power back to the charger). As another example, the cell may be controlled so that the start of the charge process is four times slower than the last discharge rate (in instances where the cell's discharge history is stored). In some embodiments, a combination of charge and discharge may be used at a fixed rate (such as when the user continues to discharge beyond where they left the cell).

[0297] According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform the refinement 620. In some embodiments, the end state of charge has a value of 60% or less. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0298] In some embodiments, the exemplary method 600A may include an optional improvement 610 that includes monitoring a characteristic of the cell. In improvement 621, a discharge rate in a state of charge range is controlled based on at least one monitored characteristic of the cell. In some embodiments, the monitored characteristic may include cell impedance and / or cell resistance. In improvement 622, the discharge rate may optionally be at least four times the average charge rate of the terminated charging steps. Alternatively or additionally, the discharge rate may optionally be at least four times the average charge rate of at least a portion of the terminated charging steps.

[0299] Further, the exemplary method 600A may include an optional refinement 630 in which a future discharge schedule may be set and executed. For example, a future discharge schedule may be set and executed such that the charging process ends and discharging begins within at least 5 and less than 50 of every 100 cycles.

[0300] In some embodiments, the end state of charge has a value of 50% or less. In some embodiments, the end state of charge has a value of 40% or less. In some embodiments, the end state of charge has a value of 30% or less. In some embodiments, the end state of charge has a value of 20% or less. In some embodiments, the end state of charge has a value of 10% or less.

[0301] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 40%. According to some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the width of the first state of charge range is at most 10%.

[0302] In some embodiments, the width of the first state of charge range is at least 5%. In some embodiments, the width of the first state of charge range is at least 10%.

[0303] In some embodiments, the discharge rate over the range of states of charge comprises an average discharge rate, hi some embodiments, the discharge rate over the range of states of charge comprises a constant discharge rate.

[0304] In some embodiments, the charge rate in the first state of charge range comprises an average charge rate. In some embodiments, the charge rate in the first state of charge range comprises a constant charge rate.

[0305] In some embodiments, the discharge rate is at least four times the average charge rate of the terminated charging steps.

[0306] In some examples, the discharge rate is controlled based on at least one monitored characteristic of the cell.

[0307] In some embodiments, a future discharge schedule is set and executed such that the charging step is terminated and discharging is initiated at least 5 and less than 50 out of every 100 cycles.

[0308] FIG. 6B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 6A. An example of the terminated charging process of FIG. 6A is shown at point 601A to point 601B of FIG. 6B. An example of the terminated charge state of FIG. 6A is shown at point 601B of FIG. 6B. An example of the state of charge range of FIG. 6A is shown at points 601B to 601C of FIG. 6B. As shown in FIG. 6B, the cell is discharged at multiple rates from about 100% to 0% state of charge to 601A, then the cell is charged from 601A to 601B to about 0% to 10% state of charge, where the charging process is terminated, and then the cell is discharged to 601C, where a more conventional charge and discharge cycle begins.

[0309] As depicted in the flow chart of FIG. 6A, the electrochemical cell is controlled at a termination charge state, e.g., time 601B in FIG. 6, as follows: As shown in FIG. 6B, the charging step is terminated, e.g., between times 601A and 601B, and discharging is initiated. During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of the terminated charging step, e.g., from time 601B to 601C. In some embodiments, during the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of the terminated charging step, e.g., from time 601B to 601C.

[0310] 7A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 700A are described in detail in the following paragraphs.

[0311] In some embodiments, the exemplary method 700A may include an improvement 720, where the electrochemical cell may be analyzed for its cycling history. In some embodiments, the exemplary method 700A may include an improvement 730, where the electrochemical cell is controlled such that a charging step is terminated at a terminal state of charge, a discharge is initiated, and during the initiated discharge, the cell is discharged over a state of charge range having a width of at least 1% and at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycling history. This may be referred to as a conditioning cycle or "mini-cycle."

[0312] According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform improvements 720 and / or 730. In some embodiments, the ending state of charge has a value of 60% or less. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0313] In some embodiments, the exemplary method 700A may include an optional improvement 710 that includes monitoring a characteristic of the cell. In improvement 731, a discharge rate in a state-of-charge range is controlled based on at least one monitored characteristic of the cell. In some embodiments, the monitored characteristic may include cell impedance and / or cell resistance. In improvement 732, the discharge rate in a state-of-charge range may optionally be at least four times the average charge rate of the cycles in the cycle history. Additionally, the flowchart may include an optional improvement 740 that may set and execute a future discharge schedule. For example, a future discharge schedule may be set and executed such that the charging process ends and discharge begins for at least 5 and less than 50 of every 100 cycles.

[0314] In some embodiments, the end state of charge has a value of 50% or less. In some embodiments, the end state of charge has a value of 40% or less. In some embodiments, the end state of charge has a value of 30% or less. In some embodiments, the end state of charge has a value of 20% or less. In some embodiments, the end state of charge has a value of 10% or less.

[0315] In some embodiments, the discharge rate over the range of states of charge comprises an average discharge rate, hi some embodiments, the discharge rate over the range of states of charge comprises a constant discharge rate.

[0316] In some embodiments, the discharge rate in the state of charge range is at least four times the average charge rate of at least one cycle in the cycling history.

[0317] In some embodiments, a future discharge schedule is set and executed such that the charging step is terminated and discharging is initiated at least 5 and less than 50 out of every 100 cycles.

[0318] In some embodiments, the discharge rate through the state of charge range is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance.

[0319] In some embodiments, the improvement 730 may include controlling the electrochemical cell such that the charging step is terminated and discharging is initiated at a terminal charge state, and the cell is discharged during the initiated discharge at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle in the cycle history over a first state of charge range having a width of at least 1%, in some embodiments, the portion including a second state of charge range having a width of at least 2% and at most 60%.

[0320] In some embodiments, the width of the second state of charge range is at most 50%. In some embodiments, the width of the second state of charge range is at most 40%. According to some embodiments, the width of the second state of charge range is at most 30%. In some embodiments, the width of the second state of charge range is at most 20%. In some embodiments, the width of the second state of charge range is at most 10%.

[0321] In some embodiments, the width of the second state of charge range is at least 5%. In some embodiments, the width of the second state of charge range is at least 10%.

[0322] In some embodiments, the charge rate in the first state of charge range comprises an average charge rate. In some embodiments, the charge rate in the first state of charge range comprises a constant charge rate.

[0323] In some embodiments, the discharge rate in the first state of charge range is at least four times the average charge rate in the second state of charge range.

[0324] FIG. 7B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 7A. An example of a terminated charging process of FIG. 7A is shown at points 701B-701C and another at points 701E-701F in FIG. 7B. An example of an end state of charge of FIG. 7A is shown at point 701C in FIG. 7B. An example state of charge range of FIG. 7A is shown at points 701C-701D in FIG. 7B. An example cycle history of FIG. 7A is shown at points 701A-701D in FIG. 7B. As shown in FIG. 7B, the cell is discharged from about 100% to 0% state of charge from 701A to 701E, then charged from about 0% to 10% state of charge from 701E to 701F, then discharged from about 10% to 0% state of charge from 701F to 701B (after the charging process from 701E to 701F is completed), then charged from about 0% to 10% state of charge from 701B to 701C, where the charging process ends and the cell is discharged from about 10% to 0% state of charge to 701D, and then a more conventional charge and discharge cycle begins.

[0325] As depicted in the flow chart of Figure 7A, the electrochemical cell is brought to a terminal charge state, e.g., at time 701C in Figure 7B, when the charging process is terminated, such as between times 701B and 701C, and discharging is initiated. During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of the terminated charging process, e.g., from time 701C to 701D.

[0326] 8A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 800A are described in detail in the following paragraphs.

[0327] In some embodiments, the exemplary method 800A may include an improvement 8200, where the electrochemical cell is controlled such that the cell is discharged and then charged over a state of charge range having a width of at least 2% and at most 60%. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform the improvement 8200. In some embodiments, the discharge rate in the discharge is at least twice the average charge rate in the charge. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0328] In some embodiments, the exemplary method 800A may include an optional improvement 8100 that includes monitoring a characteristic of the cell. In an improvement 8210, a discharge rate through a state of charge range is controlled based on at least one monitored characteristic of the cell. In some embodiments, the monitored characteristic may include cell impedance and / or cell resistance.

[0329] In improvement 8220, the cell may optionally be controlled such that charging occurs immediately after discharging. In improvement 8230, the discharge rate in the state of charge range may optionally be at least four times the average charge rate during charging.

[0330] In some embodiments, the improvement 8200 may include controlling the electrochemical cell such that the cell is discharged and then charged, and during at least a portion of the discharging covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during the portion of the discharging is at least twice the average charge rate during at least a portion of the charging. In some embodiments, the portion of the charging may include a second state of charge range having a width of at least 2% and at most 60%.

[0331] In some embodiments, controlling the electrochemical cell includes performing a discharge in response to an analysis of a previous charge step. Alternatively or additionally, controlling the electrochemical cell includes performing a charge in response to an analysis of a previous discharge step.

[0332] In some embodiments, the improvement 8230 may include the discharge rate in the first state of charge range being optionally at least four times the average charge rate in the second state of charge range.

[0333] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 40%. According to some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the width of the first state of charge range is at most 10%.

[0334] In some embodiments, the width of the second state of charge range is at most 50%. In some embodiments, the width of the second state of charge range is at most 40%. According to some embodiments, the width of the second state of charge range is at most 30%. In some embodiments, the width of the second state of charge range is at most 20%. In some embodiments, the width of the second state of charge range is at most 10%.

[0335] In some embodiments, the width of the first state of charge range is at least 5%. In some embodiments, the width of the first state of charge range is at least 10%.

[0336] In some embodiments, the width of the second state of charge range is at least 5%. In some embodiments, the width of the second state of charge range is at least 10%.

[0337] In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the first state of charge range may be uninterrupted by a discharging step. In some embodiments, the second state of charge range has a minimum state of charge of 5% or less.

[0338] The present inventors have recognized and appreciated that a state of charge range having a minimum below a certain state of charge percentage, for example 5%, is particularly effective in producing the improvements described herein.

[0339] In some embodiments, the discharge rate in the first state of charge range comprises an average discharge rate, hi some embodiments, the discharge rate in the first state of charge range comprises a constant discharge rate.

[0340] In some embodiments, the charge rate in the second state of charge range comprises an average charge rate. In some embodiments, the charge rate in the second state of charge range comprises a constant charge rate.

[0341] FIG. 8B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 8A. One example of the state of charge range of FIG. 8A is shown at points 801A to 801B in FIG. 8B. As shown in FIG. 8B, the cell is discharged to 801A, then discharged more quickly from 801A to 801B, and then a more typical charge and discharge cycle begins. In this example, the state of charge range from 801A to 801B is approximately 10% to 0%, with a width of 10%.

[0342] 9A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 900A are described in detail in the following paragraphs.

[0343] In some embodiments, the representative method 900A may include an improvement 9200 in which it is determined whether a fast charge request has been received. For example, it may be determined whether a fast charge request has been received since the immediately preceding discharge step. In some embodiments, the representative method 900A may include an improvement 9300 in which if a fast charge request has not been received (or the system is not set to a fast charge mode), the cell is controlled to be charged. The first state of charge range has a width of at least 2% and at most 60%, and then the cell is charged over a second state of charge range. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform the improvement 9200 and / or 9300. In some embodiments, the fast charge request includes a request to charge at a charge rate higher than a default charge rate.

[0344] In some embodiments, the second state of charge range has an amplitude of at least 2% and at most 60%.

[0345] According to some embodiments, the average charge / discharge rate may be calculated using the techniques described herein. According to some embodiments, the charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range. In some embodiments, the first state of charge range may be any part of the charging process. In some embodiments, the second state of charge range may be any part of the discharging process.

[0346] In some embodiments, the representative method 900A may include an optional refinement 9310, in which if a fast charge request is received (or the system is set to a fast charge mode), the cell is controlled to be charged at a charge rate higher than the default charge rate, and then after the next discharge step, the cell is controlled to be charged over a first state of charge range having a width of at least 2% and at most 60%, and then over a second state of charge range, in case the charge rate is lower than the default charge rate, after the next discharge step.

[0347] In some embodiments, the exemplary method 900A may include an optional improvement 9100 that includes monitoring a characteristic of the cell. In improvement 9303, a charge rate in a first state of charge range is controlled based on at least one monitored characteristic of the cell. In improvement 9302, the charge rate in the first state of charge range may be at most 0.25 times the average charge rate in the second state of charge range.

[0348] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 40%. According to some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the width of the first state of charge range is at most 10%.

[0349] In some embodiments, the width of the second state of charge range is at most 50%. In some embodiments, the width of the second state of charge range is at most 40%. According to some embodiments, the width of the second state of charge range is at most 30%. In some embodiments, the width of the second state of charge range is at most 20%. In some embodiments, the width of the second state of charge range is at most 10%.

[0350] In some embodiments, the width of the first state of charge range is at least 5%. In some embodiments, the width of the first state of charge range is at least 10%.

[0351] In some embodiments, the width of the second state of charge range is at least 5%. In some embodiments, the width of the second state of charge range is at least 10%.

[0352] In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the first state of charge range may be uninterrupted by a discharging step. In some embodiments, the second state of charge range has a minimum state of charge of 5% or less.

[0353] In some embodiments, the fast charge request includes a request to charge at a charge rate that is higher than a default charge rate.

[0354] In some embodiments, the at least one controller controls the cells to be charged at a charge rate higher than a default charge rate when a fast charge request is received, and then after a next discharge step, the cells are charged over a first state of charge range having a width of at least 2% and at most 60%, and then charged over a second state of charge range.

[0355] In some examples, the charge rate in the first state of charge range is controlled based on at least one monitored characteristic of the cell including cell impedance and / or cell resistance.

[0356] In some embodiments, the charge rate in the first state of charge range comprises an average charge rate. In some embodiments, the charge rate in the first state of charge range comprises a constant charge rate.

[0357] In some embodiments, the charge rate in the second state of charge range comprises an average discharge rate. In some embodiments, the charge rate in the second state of charge range comprises a constant charge rate.

[0358] In some embodiments, the charge rate in the first state of charge range is at most 0.25 times the average charge rate in the second state of charge range.

[0359] FIG. 9B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 9A. An example of the first state of charge range of FIG. 9A is shown at points 901A to 901B in FIG. 9B. An example of the second state of charge range of FIG. 9A is shown at points 901B to 901C in FIG. 9B. As shown in FIG. 9B, the cell is discharged at multiple rates to 901A, then charged from 901A to 901B, and then charged at a faster rate from 901B to 901C before beginning another discharge and charge cycle. In this example, the first state of charge range from 901A to 901B is about 0% to 10%, with a width of 10%, and the second state of charge range from 901B to 901C is about 10% to 100%, with a width of 90%.

[0360] 10A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 1000A are described in detail in the following paragraphs.

[0361] In some embodiments, the representative method 1000A may include an improvement 1020, in which the cell is controlled to be discharged and then immediately charged over a first state-of-charge range having a width of at least 2% and at most 60%, and a future charging schedule is set such that a criterion is met by the end of four cycles that go through the cycle that includes the first state-of-charge range. In some embodiments, the representative method 1000A may include an improvement 1030, in which a future charging schedule is executed. According to some embodiments, the criterion includes the cell being charged over a second state-of-charge range such that the charge rate in the first state-of-charge range is at most 0.5 times the average charge rate in the second state-of-charge range. According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may execute the improvement 1020 and / or 1030. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0362] In some embodiments, exemplary method 1000A may include an optional improvement 1010 that includes monitoring a characteristic of the cell. In improvement 1023, a charge rate in the first state of charge range may be controlled based on at least one monitored characteristic of the cell. In improvement 1020, as described in improvement 1022, the charge rate in the first state of charge range may be at most 0.25 times the average charge rate in the second state of charge range.

[0363] Additionally, exemplary method 1000A may include an optional refinement 1031 in which future charging schedules are set such that by the end of the four cycles, only one cycle includes the second state of charge range. According to some embodiments, exemplary method 1000A may also include an optional refinement 1032 in which future charging schedules are set such that a criterion is met by the end of a cycle that includes the first state of charge range.

[0364] In some embodiments, the width is at most 50%. In some embodiments, the width is at most 40%. According to some embodiments, the width is at most 30%. In some embodiments, the width is at most 20%. In some embodiments, the width is at most 10%.

[0365] In some embodiments, the range is at least 5%. In some embodiments, the range is at least 10%.

[0366] In some embodiments, the state of charge range has a minimum state of charge of 5% or less.

[0367] In some examples, the future charging schedule is set such that by the end of four cycles, only one cycle includes the second state of charge range. According to some embodiments, the future charging schedule is set such that the criteria is met by the end of a cycle that includes the first state of charge range.

[0368] In some examples, the charge rate in the first state of charge range is controlled based on at least one monitored characteristic of the cell, including cell impedance and / or cell resistance. According to some embodiments, initiation of charging in the first state of charge range may include conditioning determined to be necessary or helpful to improve the health of the cell based on this monitoring.

[0369] In some embodiments, the charge rate in the first state of charge range comprises an average charge rate. In some embodiments, the charge rate in the first state of charge range comprises a constant charge rate.

[0370] In some embodiments, the charge rate in the first state of charge range is at most 0.25 times the average charge rate in the second state of charge range.

[0371] FIG. 10B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 10A. An example of the first state of charge range of FIG. 10A is shown at points 1001A to 1001B in FIG. 10B. An example of the second state of charge range of FIG. 10A is shown at points 1001B to 1001C in FIG. 10B. Another example of the second state of charge range of FIG. 10A is shown at points 1001D to 1001E in FIG. 10B. As shown in FIG. 10B, the cell is discharged at multiple rates to 1001A, then charged from 1001A to 1001B, then charged at a higher rate from 1001B to 1001C, then discharged at multiple rates, then charged to 1001D, and then charged from 1001D to 1001E. In this example, the first state of charge range from 1001A to 1001B is from about 10% to 0%, having a width of 10%.

[0372] FIG. 10C is an exemplary capacity-cycle graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A). FIG. 10C includes six plots, each pair of plots overlaps almost completely and are therefore grouped into three main plots, denoted A, B, and C, herein. The inventors have recognized and understood that, as FIG. 10C shows in plot A, unmodified cycle testing (in this example, the charge rate is twice the discharge rate) may cause cycle life degradation compared to schemes such as those shown in plots B and C. In contrast, in plot B, the first 10% of the SOC range of the charge step has a charge rate of C / 12, followed by a charge rate of C / 5, followed by a discharge step with a discharge rate of C / 10, and the last 10% of the SOC range of the discharge step is 4C / 3. In plot C, the first 25% of the SOC range of the charge step is at a charge rate of C / 12, followed by a charge rate of C / 5, followed by a discharge step at a discharge rate of C / 10, and the last 25% of the SOC range of the discharge step is at 4C / 3. The inventors have recognized and appreciated that, as shown in FIG. 10C, the cycle life improvements described herein can be achieved at a variety of ratios (e.g., the ratios shown in both plots B and C), some of which may be more unfavorable for lithium plating and stripping, and that the advantages of using the rate ratios described herein are particularly pronounced when used at the beginning or end of the charge and discharge steps.

[0373] 11A is a flow chart illustrating an additional exemplary method for managing an electrochemical cell, according to some embodiments. The electrochemical cell may be, for example, the exemplary electrochemical cell 121A of FIG. 1A. Improvements to the exemplary method 1100A are described in detail in the following paragraphs.

[0374] In some embodiments, the exemplary method 1100A may include improving 1110 by monitoring a characteristic of the cell indicative of a loss of lithium. According to some embodiments, the loss of lithium may include a decrease in the amount of lithium in the cell that participates in an electrochemical reaction during charging or discharging. In some embodiments, the loss of lithium may be due to an undesired reaction between lithium and other cell materials, which may result in the lithium being unable to participate in an electrochemical reaction in which the cell is configured to generate an electric current. For example, the at least one characteristic may be indicative of a parasitic reaction between the lithium in the cell and at least one other material in the cell. Examples of the at least one other material in the cell may include a portion of the electrolyte of the cell or a portion of the counter electrode of the cell.

[0375] According to some embodiments, the loss of lithium in the cell includes the loss of metallic lithium in the cell. According to some embodiments, the cell includes metallic lithium at at least one point during the discharge of the cell. For example, the metallic lithium may be in the form of a film or foil sheet of lithium metal.

[0376] According to some embodiments, the at least one monitored characteristic includes at least one morphological characteristic of the cell. For example, the at least one morphological characteristic of the cell may include a value or change in at least one of pressure, thickness, volume, deflection, conductivity, resistance, or temperature. The inventors have recognized and understood that at a given charge or discharge rate, if the cell temperature rise (as one example) is higher than expected, it indicates an increase in resistance, which may indicate lithium loss. For example, if a temperature rise rate of X at a charge rate of Y is expected and the cell rises at 105% of X, it may indicate lithium loss.

[0377] In some embodiments, the exemplary method 1100A may include an improvement 1120, where a charge or discharge rate of the cell is controlled based on at least one monitored characteristic of the cell.

[0378] In some embodiments, exemplary method 1100A may also include an optional refinement 1122, where the charge or discharge rate is controlled such that for at least a portion of the discharge covering a first state of charge range having a width of at least 2% and at most 60%, the average discharge rate during the portion of the discharge is at least twice the average charge rate during at least a portion of the charge.

[0379] According to some embodiments, a controller (e.g., controller 114 of FIG. 1A) may perform improvements 1110, 1120, and / or 1122. According to some embodiments, the average charge / discharge rate may be calculated using techniques described herein.

[0380] In some embodiments, the exemplary method 1100A may also include an optional refinement 1123, in which an average discharge rate during the discharging portion is at least four times the average charge rate during the charging portion.

[0381] In some embodiments, the portion of the charge may include a second state of charge range having a width of at least 2% and at most 60%.

[0382] In some embodiments, the width of the first state of charge range is at most 50%. In some embodiments, the width of the first state of charge range is at most 40%. According to some embodiments, the width of the first state of charge range is at most 30%. In some embodiments, the width of the first state of charge range is at most 20%. In some embodiments, the width of the first state of charge range is at most 10%.

[0383] In some embodiments, the width of the second state of charge range is at most 50%. In some embodiments, the width of the second state of charge range is at most 40%. According to some embodiments, the width of the second state of charge range is at most 30%. In some embodiments, the width of the second state of charge range is at most 20%. In some embodiments, the width of the second state of charge range is at most 10%.

[0384] In some embodiments, the width of the first state of charge range is at least 5%. In some embodiments, the width of the first state of charge range is at least 10%.

[0385] In some embodiments, the width of the second state of charge range is at least 5%. In some embodiments, the width of the second state of charge range is at least 10%.

[0386] In some embodiments, the first state of charge range has a minimum state of charge of 5% or less. In some embodiments, the first state of charge range may be uninterrupted by a discharging step. In some embodiments, the second state of charge range has a minimum state of charge of 5% or less.

[0387] In some embodiments, the discharge rate in the first state of charge range comprises an average discharge rate, hi some embodiments, the discharge rate in the first state of charge range comprises a constant discharge rate.

[0388] In some embodiments, the charge rate in the second state of charge range comprises an average discharge rate. In some embodiments, the charge rate in the second state of charge range comprises a constant charge rate.

[0389] To illustrate one example where pressure is monitored and a charge / discharge scheme implemented in response to that monitoring, a pressure sensor (such as a piezoelectric force transducer or strain gauge) may be used to measure the pressure between or within the cells in the block. In some embodiments, if a threshold increase in pressure is detected, then a scheme can be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase is at least 0.1 kg / cm per cycle. 2 For example, the increase in threshold may be 0.2 kg / cm per cycle. 2 In some embodiments, the threshold increase is at least 0.5 kg / cm above the initial pressure. 2 For example, the increase in threshold may be 1 kg / cm above the initial pressure. 2 In some embodiments, the threshold increase may be at least 1% per cycle. For example, the threshold increase may be 2% per cycle. In some embodiments, the threshold increase may be at least 5% higher than the initial pressure. For example, the threshold increase may be 10% higher than the initial pressure.

[0390] To illustrate one example where thickness is monitored and a charge / discharge scheme is implemented in response to the monitoring, a thickness sensor (e.g., a strain gauge) may be used to determine the thickness of the cell. In some embodiments, if a threshold increase in thickness is detected, a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase may be at least 0.05% per cycle. For example, the threshold increase may be 0.1% per cycle. In some embodiments, the threshold increase may be at least 2.5% greater than the initial thickness. For example, the threshold increase may be at least 5% greater than the initial thickness.

[0391] To illustrate one example where volume is monitored and a charge / discharge scheme is implemented in response to the monitoring, a volume sensor (e.g., a strain gauge) may be used to determine the volume of the cell. In some embodiments, if a threshold increase in volume is detected, a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase may be at least 0.05% per cycle. For example, the threshold increase may be 0.1% per cycle. In some embodiments, the threshold increase may be at least 2.5% greater than the initial volume. For example, the threshold increase may be at least 5% greater than the initial volume.

[0392] To illustrate one example where deflection is monitored and a charge / discharge scheme implemented in response to the monitoring, a deflection sensor (e.g., a strain gauge) may be used to determine the deflection of the cell. In some embodiments, if a threshold increase in deflection is detected, a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase is at least 0.2 kg / cm per cycle. 2 In some embodiments, the threshold increase is at least 1 kg / cm above the initial deflection. 2 In some embodiments, the threshold increase may be 2% per cycle or 10% greater than the initial deflection.

[0393] To illustrate one example where conductivity is monitored and a charge / discharge scheme is implemented in response to the monitoring, a conductivity sensor may be used to measure the conductivity in the cell. In some embodiments, if a threshold decrease in conductivity is detected, then a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold decrease may be at least 0.25% per cycle. For example, the threshold decrease may be 0.5% per cycle. In some embodiments, the threshold decrease may be at least 2.5% greater than the initial conductivity. For example, the threshold decrease may be 5% greater than the initial conductivity.

[0394] To illustrate one example where resistance is monitored and a charge / discharge scheme is implemented in response to the monitoring, a resistance sensor may be used to measure the resistance in the cell. In some embodiments, if a threshold increase in resistance is detected, a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase may be at least 0.25% per cycle. For example, the threshold increase may be 0.5% per cycle. In some embodiments, the threshold increase may be at least 2.5% greater than the initial conductivity. For example, the threshold increase may be 5% greater than the initial conductivity.

[0395] To illustrate one example where temperature is monitored and a charge / discharge scheme implemented in response to that monitoring, a temperature sensor (such as a thermistor or thermocouple) may be used to determine the temperature or rate of temperature change of the cell. In some embodiments, if a threshold increase in temperature is detected, a scheme may be initiated such that the average discharge rate in the discharge portion is at least twice the average charge rate in the charge portion. In some embodiments, the threshold increase may be at least 2.5% greater than the expected increase at a given charge or discharge rate. For example, the threshold increase may be 5% greater than the expected increase at a given charge or discharge rate.

[0396] FIG. 11B is an exemplary charge-time graph of a representative electrochemical cell management system that manages an electrochemical cell (e.g., electrochemical cell 121A) in accordance with the method described in FIG. 11A. An example of the first state of charge range of FIG. 11A is shown from point 1101C to point 1101D of FIG. 11B. An example of the second state of charge range of FIG. 11A is shown from point 1101A to point 1101C of FIG. 11B. Another example of the second state of charge range of FIG. 11A is shown from point 1101D to point 1101E of FIG. 11B. As shown in FIG. 11B, the cell is discharged at multiple rates to 1101A, then charged from 1101A to 1101B, then charged at a higher rate from 1101B to 1101C, then discharged at multiple rates to 1101D, and then charged from 1101D to 1101E. In this example, the first state of charge range from 1101A to 1101B is from about 10% to 0%, having a width of 10%.

[0397] FIG. 11C illustrates an exemplary battery pack 1101. In some embodiments, the exemplary battery pack 1101 may include a switching control system (e.g., 1102) and one or more batteries (e.g., 120, 130, 140, 150, etc.). Although only a single switching control system 1102 and four batteries 120-150 are shown in FIG. 11C, it should be understood that any suitable number of these components may be used. Any of a number of different implementations may be employed. Additionally, although singular labels are used herein to refer to the switching control system, it should be understood that the components used for control and switching described herein may be distributed across any suitable number of devices (e.g., switches, controllers, etc.).

[0398] In some embodiments, the cycle may be programmed and / or controlled by a charger (such as a wall charger) that may be applied to the pack. In some embodiments, the cycle may be programmed and / or controlled by a battery management system (BMS) of the battery pack, which may apply to one or more modules. In some embodiments, the cycle may be programmed and / or controlled by a BMS in a module, which may apply to the cells. In some examples, charge may be transferred from one module to another in the pack at a favorable rate, for example, a 1:4 charge to discharge rate, and with a limited depth of discharge (DOD) (e.g., 10%). In some examples, charge may be transferred from one or more cells in a module to other cells at a favorable rate, for example, a 1:4 charge to discharge rate, and with a limited DOD, for example, 10%.

[0399] In some embodiments, the switching control system (e.g., 1102) may include an array of switches, which may include a controller, as further described in connection with FIG. 12A and FIG. 12B below. Additionally, the switching control system may be connected to each set of cells and / or to each cell of the battery individually, as described in connection with FIG. 1C above. In some embodiments, the switching control system may be incorporated into the battery pack. Additionally, the switching control system may control the switches (e.g., in the switch array) to sequentially discharge the set of cells, such as in a predefined order associated with the set of cells. Alternatively or additionally, the switching control system may control the switches to discharge the set of cells based on any one or more of the duration of the connection between the load and the set of cells currently connected to the load (which may be at least 0.01 seconds in some embodiments), the delivered discharge capacity in the connection, and the value of the function. In some embodiments, the basis for the control may not include the number of previous discharge cycles of the set of cells.

[0400] According to some embodiments, the switching control system may perform any number of other functions, such as the functions of the controller described in connection with FIGS. 1A and 1C above.

[0401] It should be understood that any of the components of the exemplary system 100 or the exemplary battery pack 1101 may be implemented using any suitable combination of hardware and / or software components. As such, the various components may be considered as controllers that may employ any suitable collection of hardware and / or software components to perform the described functions.

[0402] FIG. 12A illustrates an exemplary battery management system 300. In some embodiments, the exemplary system 300 may include any suitable number of multi-cell blocks (e.g., 921-925), which may be cell strings as described herein, battery cell block arrangements and balance switch configurations (e.g., 926), which may be string arrangements and balance switch configurations as described herein, a microcontroller (e.g., 927), which may be a cell string microcontroller, a battery system interface (e.g., 928), battery power terminals (e.g., 929), and sensors (e.g., 960). The multi-cell blocks may be connected to the battery cell block arrangements and balance switch configurations. The multi-cell blocks may also be connected to a battery management microcontroller. In some embodiments, the cell strings may be connected to the string arrangements and balance switch configurations, as well as individual battery management microcontrollers, which may then be connected to string microcontrollers as described herein.

[0403] In some embodiments, the battery cell block arrangement and balancing switch configuration may include switch multiplexing, which may connect the cell blocks (e.g., 921-925) in series, parallel, series / parallel, or other suitable topology necessary to meet the voltage and current requirements of a given application or load.

[0404] According to some embodiments, the battery management microcontroller may monitor and control the charging and discharging of the battery management system to ensure safe operation of the system and its elements. Additionally, the battery management microcontroller may communicate with users (e.g., consumers who use the system to power loads), as well as any suitable internal production, calibration, and test equipment. For example, the battery management microcontroller may be connected to a battery system interface (e.g., 928), which may provide the necessary interface for the battery management microcontroller to communicate with users as well as internal production, calibration, and test equipment, and any other suitable entities.

[0405] In some embodiments, sensors may be connected to the battery cell block arrangement and balance switch configuration, the battery management microcontroller, and / or the battery power terminals that may measure attributes of the multi-cell block and / or any other element of the system. For example, the sensors may measure attributes of the multi-cell block that form any of the criteria and / or function parameters as described above. For example, the sensors may include current sensors that measure the current in amperes of a given set of cells.

[0406] Although the battery cell block arrangement and balance switch configuration 926, battery management microcontroller 927, battery system interface 928, and sensor 960 appear in the singular and only five multi-cell blocks 921-925 are shown in FIG. 12A, it should be understood that any suitable number of these components may be used and they may represent multiple components. Any of a number of different implementations may be employed. Indeed, although singular labels are used herein to refer to the battery cell block arrangement and balance switch configurations, it should be understood that the components used in the arrangements and balance switches described herein may be distributed among any suitable number of devices (e.g., switches).

[0407] FIG. 12B is a diagram illustrating a representative cell set and corresponding components. In some embodiments, the representative cell set may include any suitable number of the cells (e.g., 921A-921C) and may form a multi-cell block as described above. In addition, the representative cell set may include a cell multiplexing switch (e.g., 926A1), the cell balance switch and resistor (e.g., 926A2), a cell block microcontroller (e.g., 927A), a battery management microcontroller interface (e.g., 928A), a sensor (e.g., 960A), and an input / output bus (e.g., 921IO) for the cell set. In some embodiments, the cells may be connected to the cell balance switch and resistor, which may be connected to the cell multiplexing switch.

[0408] In some embodiments, each cell (e.g., each of 921A-921C) may be connected to an array of cell multiplexing switches, which may connect or isolate a given cell from an input / output bus (e.g., 921IO) and may connect or isolate a given cell to a balance resistor (e.g., one of the resistors in 926A2) that shares the balance bus with other cells. Furthermore, in a discharge mode, one cell (e.g., 921A) may be connected to the input / output bus and isolated from the balance resistor. The remaining cells (e.g., 921B-921C) may be isolated from the input / output bus and connected to corresponding balance resistors. Furthermore, in a charge mode according to some embodiments, all cells (e.g., 921A-921C) may be connected to the input / output bus and isolated from the balance resistor 926A2.

[0409] According to some embodiments, the cell block microcontroller (e.g., 927A) may generate switching waveforms to ensure that the overlap and deadband requirements for switching are appropriate for the application or load. Additionally, the cell block microcontroller may determine the state required by an application or load by monitoring the cell block voltage and current and by receiving communications from a battery management microcontroller (e.g., 927 in FIG. 12A) to which the cell block microcontroller may be connected via a battery management microcontroller interface.

[0410] 12C is an exemplary cross-sectional schematic diagram of an electrochemical system in which an anisotropic force is applied to an electrochemical cell (e.g., 921A) according to one set of embodiments. As used herein, the term "electrochemical cell" is used generally to refer to an anode, a cathode, and an electrolyte configured to participate in an electrochemical reaction to generate electrical power. An electrochemical cell can be rechargeable or non-rechargeable.

[0411] In FIG. 12C, the system may include an electrochemical cell 921A and, in some embodiments, a pressure distributor 934 that includes a fluid associated with the electrochemical cell 921A. The pressure distributor 934 may be configured to apply an anisotropic force to a component of the electrochemical cell 921A via the pressure distributor 934. For example, in the set of embodiments illustrated in FIG. 12C, the pressure transmitter 936 may be configured to apply an anisotropic force to the pressure distributor 934, which in turn applies an anisotropic force to at least one component (e.g., an electrode) of the electrochemical cell 921A. The system may also include a substrate 932 on which the electrochemical cell is disposed. The substrate 932 may include, for example, a table surface, a surface of a vessel in which the electrochemical cell 921A is housed, or any other suitable surface.

[0412] The pressure distributor 934 can be associated with the electrochemical cell 921A in a variety of suitable configurations to fabricate the inventive systems and methods described herein. As used herein, a pressure distributor is associated with an electrochemical cell when at least a portion of the force applied to and / or through the pressure distributor may be transferred to a component of the electrochemical cell. For example, in some embodiments, a pressure distributor is associated with an electrochemical cell when the pressure distributor is in direct contact with the electrochemical cell or a component thereof. In general, a first item and a second item are in direct contact when the first item and the second item are in direct contact with each other. For example, in FIG. 12C, the pressure distributor 934 and the electrochemical cell 921A are in direct contact.

[0413] In some embodiments, the pressure distributor is associated with an electrochemical cell when the pressure distributor is in indirect contact with at least one component of the electrochemical cell. In general, the first and second articles are in indirect contact when a path that crosses only solid and / or liquid components may be found between the first and second articles. Such a path may be in the form of a substantially straight line in some embodiments. The pressure distributor may indirectly contact the electrochemical cell when one or more solid and / or liquid materials are disposed between them, but still force can be transmitted to the electrochemical cell through the pressure distributor.

[0414] In some embodiments, a pressure distributor is associated with an electrochemical cell when it is located within the boundaries of a container that at least partially (e.g., completely) surrounds the components of the electrochemical cell. For example, in some embodiments, the pressure distributor 934 may be positioned between an electrode and a container that at least partially surrounds the electrochemical cell. In some embodiments, the pressure distributor 934 may be positioned between a current collector and a container that at least partially surrounds the electrochemical cell. In some embodiments, the pressure distributor 934 may be used as a current collector, for example, located next to an electrode of the electrochemical cell and within a container that at least partially contains the electrode and electrolyte of the electrochemical cell. This may be accomplished, for example, by fabricating the pressure distributor 934 from a material (e.g., a metal such as a metal foil, a conductive polymer, etc.) that has sufficient electrical conductivity to transport electrons to and / or from the electrodes of the electrochemical cell.

[0415] In some embodiments, a pressure distributor is associated with an electrochemical cell if it is located outside the boundaries of a container that at least partially (e.g., completely) encloses the components of the electrochemical cell. For example, in some embodiments, the pressure distributor 934 may be positioned to directly or indirectly contact an exterior surface of a container that at least partially encloses the electrodes and electrolyte of the electrochemical cell.

[0416] In some embodiments, the pressure distributor may be disposed a relatively short distance from at least one electrode of the electrochemical cell, for example, in some embodiments, the shortest distance between the pressure distributor and an electrode of the electrochemical cell is at most about 10 times, about 5 times, about 2 times, about 1 time, about 0.5 times, or about 0.25 times the cross-sectional dimension of the electrode.

[0417] In some embodiments, the pressure distributor can be associated with a particular electrode (e.g., an anode) of the electrochemical cell. For example, the pressure distributor can be in direct or indirect contact with an electrode (e.g., an anode, such as an anode containing lithium) of the electrochemical cell. In some embodiments, the pressure distributor may be located outside of a container that at least partially contains the electrode but is still associated with the electrode, e.g., when only liquid and / or solid components separate the electrode from the pressure distributor. For example, in some embodiments where the pressure distributor is located in direct or indirect contact with a container that at least partially surrounds the electrode and liquid electrolyte, the pressure distributor is associated with the electrode.

[0418] In some embodiments, force can be applied to the electrochemical cell 921A or a component of the electrochemical cell 921A (e.g., an electrode of the electrochemical cell) through pressure distributor 934. As used herein, force is applied to a first component (e.g., an electrochemical cell) through a second component (e.g., a pressure distributor) when the second component at least partially transmits force from a source of force to the first component.

[0419] A force can be applied to the electrochemical cell or a component thereof via the pressure distributor in a variety of ways. In some embodiments, applying a force to the pressure distributor includes applying a force to an exterior surface of the pressure distributor. This may be accomplished, for example, via a pressure transmitter 936. For example, in FIG. 12C, the pressure transmitter 936 may be positioned to apply an anisotropic force to the electrochemical cell 921A via the pressure distributor 934 by applying a force to a surface 940 of the pressure distributor 934. As used herein, a first component is positioned to apply an anisotropic force to a second component when the first and second components are positioned such that at least a portion of a force applied to and / or via the first component may be transmitted to the second component. In some embodiments, the pressure transmitter and the pressure distributor are in direct contact. In some embodiments, one or more materials (e.g., one or more solid and / or liquid materials) are disposed between the pressure transmitter and the pressure distributor, but a force may still be applied to the pressure distributor by the pressure transmitter. In some embodiments, the pressure transmitter and the pressure distributor may be in indirect contact such that a continuous path may be traced through the solid and / or liquid materials from the pressure distributor to the electrochemical cell. Such a path may be substantially (e.g., completely) linear in some embodiments.

[0420] 12C, pressure transmitter 936 and electrochemical cell 921A are positioned on opposite sides of pressure distributor 934. Thus, when an anisotropic force (e.g., an anisotropic force in the direction of arrow 150) is applied to and / or by pressure transmitter 936 to surface 940, said force may be transmitted through pressure distributor 934 onto surface 942 of electrochemical cell 921A and to components of electrochemical cell 921A.

[0421] In some embodiments, applying a force to the pressure distributor includes applying a force to an interior surface of the pressure distributor. For example, in some embodiments, a force can be applied to the electrochemical cell through the pressure distributor by maintaining and / or increasing the pressure of the fluid in the pressure distributor. In one set of embodiments illustrated in FIG. 12C, a force can be applied to the electrochemical cell 921A through the pressure distributor 934 by transporting additional fluid through an inlet (not shown) of the pressure distributor 934 (e.g., by expanding the pressure distributor 934). In some such embodiments, the movement of the pressure transmitter can be restricted such that as the pressure in the pressure distributor is maintained and / or increased, a force is generated on an exterior surface of the electrochemical cell and / or a component of the electrochemical cell (e.g., an active surface of an electrode in the electrochemical cell). For example, in FIG. 12C, as additional fluid is applied to the pressure distributor 934, the pressure transmitter 936 can be configured to restrict movement of a boundary of the pressure distributor 934 such that a force is applied to a surface 942 of the electrochemical cell 921A.

[0422] In some embodiments, fluid can be applied to the pressure distributor 934 before the pressure distributor 934 is disposed between the electrochemical cell 921A and the pressure transmitter 936. After the fluid is applied, the pressure distributor 934 can be compressed and positioned between the electrochemical cell 921A and the pressure transmitter 936, and the compression of the fluid in the pressure distributor 934 can then cause a force to be applied to the surface 942 of the electrochemical cell 921A (and correspondingly, to the surface of one or more components of the electrochemical cell, such as the active surfaces of the electrodes). One of ordinary skill in the art in view of this disclosure can design additional systems and methods that can apply a force to an electrochemical cell through a pressure distributor.

[0423] The fluid in pressure distributor 934 may cause the pressure transmitted through pressure distributor 934 to be applied relatively evenly across surface 942 of electrochemical cell 921A (and correspondingly, across the surfaces of one or more components of the electrochemical cell, such as the active surfaces of the electrodes). Without wishing to be bound by theory, it is believed that the presence of fluid in pressure distributor 934 reduces and / or eliminates points of relatively high pressure on surface 942 as fluid in areas of relatively high pressure is transported to areas of relatively low pressure.

[0424] In some embodiments, the degree to which the pressure distributor evenly distributes the force applied to the electrochemical cell may be enhanced if the outer surface of the pressure transmitter is properly aligned with the outer surface of the electrochemical cell or its container. For example, in the set of embodiments illustrated in FIG. 12C, the outer surface 940 of the pressure transmitter 936 faces the outer surface 942 of the electrochemical cell 921A. In some embodiments, the outer surface of the pressure transmitter is substantially parallel to the outer surface of the electrochemical cell to which the force is applied. For example, in the set of embodiments illustrated in FIG. 12C, the outer surface 940 of the pressure transmitter 936 is substantially parallel to the outer surface 942 of the electrochemical cell 921A. As used herein, two surfaces are substantially parallel to each other when the two surfaces form an angle of about 10 degrees or less. In some embodiments, two substantially parallel surfaces form an angle of about 5 degrees or less, an angle of about 3 degrees or less, an angle of about 1 degree or less, or an angle of about 0.1 degrees or less.

[0425] The pressure distributor may have a variety of suitable forms. In some embodiments, the pressure distributor may comprise a bag or other suitable container in which the fluid is contained. In some embodiments, the pressure distributor may comprise bellows configured to deform along a direction in which force is applied to the pressure distributor.

[0426] The pressure distributor vessel can be made of a variety of materials. In some embodiments, the pressure distributor vessel may include a flexible material. For example, in some embodiments, the pressure distributor vessel may include a polymer such as polyethylene (e.g., linear low density and / or very low density polyethylene), polypropylene, polyvinyl chloride, polyvinyl dichloride, ethylene vinyl acetate, polycarbonate, polymethacrylate, polyvinyl alcohol, nylon, silicone rubber (e.g., polydimethylsiloxane), and / or other natural or synthetic rubber or plastic. In some embodiments (e.g., in embodiments in which gas is used as the fluid in the pressure distributor), the pressure distributor vessel may include a metal layer (e.g., an aluminum metal layer), which may improve the degree to which the fluid (e.g., gas) is retained within the pressure distributor. The use of a flexible material is advantageous in some embodiments because it may allow the contents of the pressure distributor to be redistributed relatively easily and may increase the degree to which force is applied evenly.

[0427] In some embodiments, the pressure distributor may include an elastic material. In some embodiments, the elasticity of the material from which the pressure distributor is manufactured may be selected so that the pressure distributor transmits a desired amount of force applied to the pressure distributor to adjacent components. By way of example, in some cases, if the pressure distributor is formed of a very flexible material, a relatively high percentage of the force applied to the pressure distributor may be used to elastically deform the pressure distributor material rather than being transmitted to the adjacent electrochemical cells. In some embodiments, the pressure distributor may be formed from a material having a Young's modulus of less than about 1 GPa. Those skilled in the art can measure the Young's modulus of a given material, for example, by performing a tensile test (sometimes also referred to as a tension test). Exemplary elastic polymers (i.e., elastomers) that may be used include the general classes of silicone polymers, epoxy polymers, and acrylate polymers.

[0428] In some embodiments, the pressure distributor comprises a sealed vessel containing the fluid. In some embodiments, the pressure distributor may comprise an open vessel containing the fluid. For example, in some embodiments, the pressure distributor comprises a vessel fluidly connected to a device configured and arranged to transport the fluid through the pressure distributor, as described in more detail below.

[0429] A variety of fluids may be used in the pressure distributor. As used herein, "fluid" generally refers to a substance that is flowable and tends to conform to the contours of its container. Examples of fluids include liquids, gases, gels, viscoelastic fluids, solutions, suspensions, fluidized particulates, and the like. In general, fluids are materials that cannot withstand static shear stress, and when shear stress is applied, the fluid experiences a continuous and permanent distortion. The fluid may have any suitable viscosity that allows for flow and redistribution of the applied force.

[0430] In some embodiments, the fluid in the pressure distributor comprises a gas (e.g., air, nitrogen, a noble gas (e.g., helium, neon, argon, krypton, xenon), a gas refrigerant, or a mixture thereof). In some embodiments, the gas in the pressure distributor may comprise a relatively high molecular weight (e.g., at least about 100 g / mol), which can limit the extent to which the gas permeates through the walls of the pressure distributor. In some embodiments, the fluid in the pressure distributor includes liquids including, but not limited to, water, electrolytes (e.g., liquid electrolytes similar or identical to those used in electrochemical cells), greases (e.g., petroleum jelly, Teflon grease, silicone grease), oils (e.g., mineral oil), and the like. In some embodiments, the fluid in the pressure distributor comprises a gel. Gels suitable for use in the pressure distributor include, but are not limited to, hydrogels (e.g., silicone gels), organogels, or xerogels. In some embodiments, the fluid comprises a fluidized bed of solid particles (e.g., sand, powder, and the like). Fluidization may be achieved, for example, by passing a gas and / or liquid through the particles and / or by vibrating a substrate on which the particles are disposed so that the particles move relative to one another.

[0431] The fluid used in connection with the pressure distributor may have any suitable viscosity. In some embodiments, a Newtonian fluid may be used in the pressure distributor, although some embodiments are not so limited and may also use non-Newtonian fluids (e.g., shear thinning fluids, shear thickening fluids, etc.). In some embodiments, the pressure distributor has a viscosity of about 1×10 at room temperature. 7 Less than 1 x 10 centipoise (cP) 6 Less than cP, approximately 1 × 10 5 The fluid may include Newtonian fluids having a steady state shear viscosity of less than about 1000 cP, less than about 100 cP, less than about 10 cP, less than about 10 cP, or less than about 1 cP (and, in some embodiments, greater than about 0.001 cP, greater than about 0.01 cP, or greater than about 0.1 cP).

[0432] In some embodiments, the fluid in the pressure distributor may be selected to be suitable for being transported into and / or out of the pressure distributor. For example, in some embodiments, a fluid may be transported into the pressure distributor to apply an anisotropic force to an electrochemical cell (e.g., by compressing the fluid in the pressure distributor when disposed between the electrochemical cell and the pressure transmitter). As another example, a fluid may be transported into and / or out of the pressure distributor to transfer heat to and / or remove heat from a system component.

[0433] The pressure transmitter 936 may also adopt various configurations. In some embodiments, the pressure transmitter 936 is movable relative to the electrochemical cell 921A. In some such embodiments, a force can be applied to the electrochemical cell 921A via the pressure distributor 934 by bringing the pressure transmitter 936 closer to the electrochemical cell 921A and / or maintaining a separation between the electrochemical cell 921A and the pressure transmitter 936. As one particular example, in some embodiments, the pressure transmitter 936 includes a compression spring, a first applicator structure, and a second applicator structure. The first applicator structure may correspond, for example, to a flat plate of a rigid material, or any other suitable structure. The second applicator structure may correspond, for example, to a second plate of a rigid material, a portion of a wall of a vessel in which the electrochemical cell is housed, or any other suitable structure. In some embodiments, a force can be applied to a surface 942 of the electrochemical cell 921A when the compression spring is compressed between the applicator structure and the applicator structure. In some embodiments, Belleville washers, machine screws, pneumatic devices, weights, air cylinders, and / or hydraulic cylinders may be used in place of or in addition to compression springs. In some embodiments, a force can be applied to the electrochemical cell using a constricting element (e.g., elastic bands, turnbuckle bands, etc.) disposed around one or more exterior surfaces of the electrochemical cell. Various suitable methods for applying force to an electrochemical cell are described, for example, in U.S. Patent Application Publication No. 2010 / 0035128, entitled "Application of Force in Electrochemical Cells," filed Aug. 4, 2009, to Scordilis-Kelley et al., which is incorporated herein by reference in its entirety for all purposes.

[0434] In some embodiments, the pressure transmitter 936 is substantially immovable relative to the electrochemical cell 921A, and a force can be applied to the electrochemical cell, for example, by pressurizing the pressure distributor 934. In some such embodiments, the substantially immovable pressure transmitter 936 limits the movement of one or more boundaries of the pressure distributor 934, thereby applying an anisotropic force to the electrochemical cell 921A, such that pressurizing the pressure distributor can result in the application of a force to the electrochemical cell.

[0435] In some embodiments, the pressure transmitter may comprise all or part of a substantially rigid structure (e.g., a package surrounding the electrochemical cell), and the movement of the pressure transmitter may be limited by the extent to which the substantially rigid structure is inflexible. In some embodiments, the pressure transmitter may comprise a structure that is integrated with at least some of the other components of the system, thereby limiting its movement. For example, in some embodiments, the pressure transmitter may comprise at least a portion of one or more walls of the package in which the electrochemical cell 921A and the pressure distributor 934 are disposed. As one particular example, the pressure transmitter 936 may form a first wall of the package containing the electrochemical cell 921A, while the substrate 932 may form a second wall of the package (e.g., opposite the first wall). In some embodiments, the movement of the pressure transmitter 936 may be limited by applying a force in and / or on the pressure transmitter such that its movement is limited. In any of these cases, in some embodiments, a force can be applied to the electrochemical cell by adding fluid to and / or maintaining the amount of fluid in the pressure distributor 934.

[0436] FIG. 12C illustrates a set of embodiments in which a single pressure transmitter and a single pressure distributor are used to apply a force to the electrochemical cell. However, in some embodiments, more than one pressure distributor and / or more than one pressure transmitter may be employed. For example, in some embodiments, the system includes a second pressure distributor disposed below the electrochemical cell 921A and a second pressure transmitter disposed below the second pressure distributor. In some embodiments, a substantially evenly distributed force can be applied to the exterior surface of the electrochemical cell 921A through the second pressure distributor, for example, by applying a force to the surface of the second pressure distributor to and / or through the second pressure transmitter.

[0437] In some embodiments, fluid can be transported to and / or from the pressure distributor to transfer heat to and / or remove heat from the electrochemical cell 921A. For example, the pressure distributor 934 may include an inlet and an outlet configured to transport fluid through the pressure distributor 934. As the fluid is transported through the pressure distributor 934, it may absorb heat from the electrochemical cell 921A and transport it away from the system via the outlet. For example, a pump, a vacuum, or any other suitable device may be used to transport the fluid through the pressure distributor.

[0438] In some embodiments, the fluid used in connection with the pressure distributor may be selected to cool or heat the system to a desired degree. For example, in some embodiments, the fluid in the pressure distributor may include a coolant such as water, ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol (PAG), oil (e.g., mineral oil, castor oil, silicone oil, fluorocarbon oil, etc.), and / or refrigerant (e.g., Freon, chlorofluorocarbon, perfluorocarbon, etc.).

[0439] The embodiments described herein may be used with a variety of electrochemical cells. While primary (disposable) and secondary (rechargeable) electrochemical cells may be used in conjunction with the embodiments described herein, some embodiments advantageously use secondary electrochemical cells, for example, due to the benefits provided by the uniform application of force during the (re)charging process. In some embodiments, the electrochemical cell comprises a lithium-based electrochemical cell (and an assembly of multiple cells, such as a battery), such as a lithium-sulfur electrochemical cell.

[0440] While some embodiments may find use in a wide variety of electrochemical devices, one example of such a device is provided for illustrative purposes only in Figure 12D. In Figure 12D, a general embodiment of an electrochemical cell 921A includes a cathode 910, an anode 912, and an electrolyte 914 in electrochemical communication with the cathode and anode.

[0441] In some embodiments, the electrochemical cell 921A can be optionally at least partially contained by a containment structure 916. The containment structure 916 can have a variety of shapes, including, but not limited to, a cylinder, a prism (e.g., triangular prism, rectangular prism, etc.), a cube, or any other shape. In some embodiments, the pressure distributor can be associated with the electrochemical cell 921A by disposing the pressure distributor outside the containment structure 916 in direct or indirect contact with the surface 918A and / or the surface 918B. When positioned in this manner, the pressure distributor can be configured to apply a force directly or indirectly to the surface 918A and / or the surface 918B of the containment structure 916, as described above. In some embodiments, the pressure distributor can be positioned between the cathode 310 and the containment structure 916, or between the anode 912 and the containment structure 916. In some such embodiments, the containment structure can function as a pressure transmitter and / or a separate pressure transmitter can be configured to apply a force to the pressure distributor via the containment structure.

[0442] A typical electrochemical cell system will, of course, also include current collectors, external circuitry, etc. Those skilled in the art will be familiar with the many configurations that may be utilized utilizing the general schematic arrangement shown in the drawings and described herein.

[0443] The components of the electrochemical cell 921A may, in some cases, be assembled such that the electrolyte is disposed between the cathode and the anode in a planar configuration. For example, in the embodiment shown in FIG. 12D, the cathode 910 of the electrochemical cell 921A is substantially planar. The substantially planar cathode may be formed, for example, by coating a cathode slurry onto a planar substrate, such as a metal foil or other suitable substrate, which may be included in the assembly of the electrochemical cell 921A (not shown in FIG. 12D) or may be removed from the cathode 910 prior to assembly of the electrochemical cell. Additionally, in FIG. 12D, the anode 912 is illustrated as being substantially planar. The substantially planar anode may be formed, for example, by forming a sheet of metallic lithium, by forming an anode slurry on a planar substrate, or by any other suitable method. The electrolyte 914 is also illustrated as being substantially planar in FIG. 12D.

[0444] In some embodiments, the electrochemical plating of lithium may start at a slow rate and then increase the current density to increase the deposition rate and grow the bulk of the film to produce a dense lithium film. For example, 25% of the average current density may be applied during the entire charge. Alternatively, the 25% current density may be applied at the end of the charge, although the inventors recognize and understand that this may preferably be before the "taper portion" of the charge. Alternatively or additionally, the electrochemical plating of lithium may form a dense lithium film on top of the already formed lithium by electrochemically removing a predetermined amount of lithium at a fast rate or current density, then depositing a starting lithium layer at 25% of the current density, and then depositing the main lithium film thickness at a fast rate. The inventors recognize and understand that such techniques may form a dense lithium film on the metal substrate, reduce the depletion of electrolyte components on the lithium surface, reduce the build-up of depletion products on the surface, slow the build-up of electrical resistance, reduce the depletion of metallic lithium, and reduce the formation of electrically isolated lithium "islands."

[0445] In some embodiments, the electrochemical cell 921A may include electrodes containing a metal, such as an elemental metal and / or a metal alloy. As one particular example, in some embodiments, the electrochemical cell 921A may include an anode containing elemental lithium (e.g., elemental lithium metal and / or a lithium alloy). In some embodiments, the anisotropic force applied to the electrochemical cell is sufficiently large such that the application of the force affects the surface morphology of the metal in the electrodes of the electrochemical cell, as described in more detail below.

[0446] Although Figure 12D shows the electrochemical cells arranged in a planar configuration, it should be understood that the principles of some embodiments can be employed to construct any electrochemical cell arrangement in any configuration. In addition to the shapes illustrated in Figure 12D, the electrochemical cells described herein may be any other shape including, but not limited to, cylinders, folded multi-layer structures, prisms (e.g., triangular prisms, rectangular prisms, etc.), "Swiss-rolls," non-planar multi-layer structures, etc. Further configurations are described in U.S. Patent Application Serial No. 11 / 400,025, filed April 06, 2006, by Affinito et al., entitled "Electrode Protection in both Aqueous and Non-Aqueous Electrochemical Cells, including Rechargeable Lithium Batteries," which is incorporated herein by reference in its entirety.

[0447] In some embodiments, the cathode and / or anode include at least one active surface. As used herein, the term "active surface" is used to describe the surface of an electrode that is in physical contact with the electrolyte and where an electrochemical reaction can occur. For example, in the set of embodiments illustrated in FIG. 12D, the cathode 910 includes a cathode active surface 920 and the anode 912 includes an anode active surface 922.

[0448] In some embodiments, the anisotropic force applied to the pressure transmitter 936 and / or via the pressure distributor 934 (and ultimately to the surface 942 of the electrochemical cell 921A in some cases) includes a component that is perpendicular to the active surface of an electrode (e.g., an anode, such as an anode comprising lithium metal) in the electrochemical cell. Thus, applying an anisotropic force to the electrochemical cell via the pressure distributor 934 can result in an anisotropic force being applied to the active surface of an electrode (e.g., an anode) in the electrochemical cell. In the case of a planar electrode surface, the applied force may include an anisotropic force having a component that is perpendicular to the electrode active surface at the point at which the force is applied. For example, with reference to the set of embodiments shown in Figures 12C and 12D, an anisotropic force in the direction of arrow 970 may be applied to the electrochemical cell 921A via the pressure distributor 934. The anisotropic force applied in the direction of arrow 970 includes a component 972 that is perpendicular to the anode active surface 922 and perpendicular to the cathode active surface 920. Additionally, an anisotropic force applied in the direction of arrow 970 will include a component 974 that is not perpendicular (and is actually parallel) to the anode active surface 922 and the cathode active surface 920 .

[0449] In the case of a curved surface (eg, concave or convex), the force applied to the electrochemical cell may include an anisotropic force having a component perpendicular to a plane tangent to the curved surface at the point at which the force is applied.

[0450] In one set of embodiments, the systems and methods are configured to apply an anisotropic force to an electrochemical cell having a component perpendicular to an active surface of an electrode (e.g., an anode) during at least one period during charging and / or discharging of the cell. In some embodiments, the force may be applied continuously, over one period, or over multiple periods that may vary in duration and / or frequency.

[0451] The magnitude of the applied force is sufficient to improve the performance of the electrochemical cell in some embodiments. In some embodiments, the electrode active surface (e.g., anode active surface) and the anisotropic force may be selected together such that the anisotropic force affects the surface morphology of the electrode active surface to suppress the increase in the electrode active surface area due to charging and discharging, resulting in a larger increase in the electrode active surface area through charging and discharging cycles in the absence of the anisotropic force, but under otherwise essentially identical conditions. By "essentially identical conditions" herein is meant conditions that are similar or identical except for the application of the force and / or the magnitude of the force. For example, otherwise identical conditions may mean a cell that is identical, but not configured (e.g., by a bracket or other connection) to apply an anisotropic force to the electrochemical cell of interest.

[0452] The electrode active surface and anisotropic force may be readily selected together by one of ordinary skill in the art to achieve the results described herein. For example, if the electrode active surface is relatively soft, the component of the force normal to the electrode active surface may be selected to be lower. If the electrode active surface is harder, the component of the force normal to the electrode active surface may be greater. One of ordinary skill in the art in view of this disclosure may readily select anode materials, alloys, mixtures, etc. with known or predictable properties, or may readily test the hardness or softness of such surfaces, and may readily select cell construction techniques and configurations to provide suitable forces to achieve what is described herein. Simple tests may be performed, for example, by placing a series of active materials, each subjecting the active materials to a series of forces normal to the active surface (or a component normal to the active surface), and determining the morphological effect of the forces on the surfaces with no cell cycling (for prediction of the selected combination during cell cycling) or with cell cycling with selection and observation of the associated results.

[0453] As discussed above, in some embodiments, during at least one period during charging and / or discharging of the cell, an anisotropic force having a component perpendicular to the electrode active surface (e.g., of the anode) is applied to an extent effective to inhibit an increase in the surface area of ​​the electrode active surface relative to the increase in surface area that would occur in the absence of the anisotropic force. The component of the anisotropic force perpendicular to the electrode active surface may be, for example, at least about 20, at least about 25, at least about 35, at least about 40, at least about 50, at least about 75, at least about 90, at least about 100, at least about 125, at least about 150, at least about 200, at least about 300, at least about 400, or at least about 500 Newtons per square centimeter (N / cm 2 In some embodiments, the component of the anisotropic force perpendicular to the anode active surface may be, for example, about 500 N / cm 2 Less than 400N / cm 2 Less than 300N / cm 2 Less than 200N / cm 2 Less than 190N / cm 2 Less than 175N / cm 2 Less than approx. 150N / cm 2 Less than approx. 125N / cm 2 Less than 115N / cm 2 Less than or about 110N / cm 2 A pressure of less than 1000 mm may be defined as a pressure of less than 1000 mm. Although force and pressure are generally described herein in units of Newtons and Newtons per unit area, respectively, force and pressure can also be expressed in units of kilograms-force (kgf) and kgf per unit area, respectively. Those skilled in the art are familiar with kgf-based units and understand that 1 kgf is equivalent to approximately 9.8 Newtons.

[0454] In some embodiments, the component of the anisotropic force perpendicular to the active surface of an electrode in an electrochemical cell defines a pressure that is at least about 50%, at least about 75%, at least about 100%, at least about 120% of the yield stress of that electrode (e.g., during charging and / or discharging of the electrochemical cell). In some embodiments, the component of the anisotropic force perpendicular to the active surface of an electrode in an electrochemical cell defines a pressure that is less than about 250% or less than about 200% of the yield stress of that electrode (e.g., during charging and / or discharging of the electrochemical cell). For example, in some embodiments, the electrochemical cell may include an anode (e.g., an anode comprising lithium metal and / or lithium alloy), and the component of the applied anisotropic force perpendicular to the anode active surface may define a pressure that is at least about 50%, at least about 75%, at least about 100%, or at least about 120% of the yield stress of the anode (and / or less than about 250% or less than about 200% of the yield stress of the anode). In some embodiments, the electrochemical cell may include a cathode, and the component of the anisotropic force perpendicular to the cathode active surface may define a pressure that is at least about 50%, at least about 75%, at least about 100%, or at least about 120% of the yield stress of the cathode (and / or less than about 250% or less than about 200% of the yield stress of the cathode).

[0455] In some cases, the anisotropic force may define a pressure that is relatively uniform across one or more external surfaces of the electrochemical cell and / or across one or more active surfaces of the electrodes in the electrochemical cell. In some embodiments, at least about 50%, at least about 75%, at least about 85%, at least about 90%, at least about 95%, or at least about 98% of the area of ​​one or more external surfaces of the electrochemical cell and / or the area of ​​one or more active surfaces of the electrodes (e.g., anodes) define a uniform region that includes a substantially uniform distribution of the pressure defined by the anisotropic force. In the description herein, the terms "surface of the electrochemical cell" and "surface of the electrode" refer to the geometric surface of the electrochemical cell and electrode, and those skilled in the art will understand that the surface that defines the outer boundary of the electrochemical cell and electrode, for example, the area that may be measured by a macroscopic measuring tool (e.g., a ruler), does not include the internal surface area (e.g., the area within the pores of a porous material such as a foam, or the surface area of ​​the fibers of a mesh that are contained within the mesh and do not define the outer boundary, etc.).

[0456] In some embodiments, pressure is substantially uniformly distributed across a surface if any continuous region covering about 10%, about 5%, about 2%, or about 1% of the uniform region (described in the previous paragraph) contains an average pressure that varies by less than about 25%, less than about 10%, less than about 5%, less than about 2%, or less than about 1% relative to the average pressure throughout the uniform region.

[0457] In other words, in some embodiments, at least about 50% (or at least about 75%, at least about 85%, at least about 90%, at least about 95%, or at least about 98%) of the area of ​​the surface of the electrochemical cell and / or the area of ​​the active area of ​​the electrode defines a first continuous region of essentially uniform applied pressure, the first region having a first average applied pressure. In some cases, any continuous region covering about 10% (or about 5%, about 2%, or about 1%) of the first continuous area of ​​the surface of the electrochemical cell and / or the electrode includes a second average applied pressure that varies by less than about 25% (or less than about 10%, less than about 5%, less than about 2%, or less than about 1%) relative to the first average applied pressure across the first continuous region.

[0458] One skilled in the art may determine the average applied pressure within a surface portion, for example, by determining the force level applied at a representative number of points within the surface portion, integrating a three-dimensional plot of applied pressure as a function of position on the surface portion, and dividing the integral by the surface area of ​​the surface portion. One skilled in the art may generate a plot of pressure across the surface portion, for example, by using a Tekscan I-Scan system to measure the pressure field.

[0459] The anode of the electrochemical cells described herein may include a variety of anode active materials. As used herein, the term "anode active material" refers to any electrochemically active species associated with the anode. For example, the anode may include a lithium-containing material, with lithium being the anode active material. Electroactive materials suitable for use as the anode active material in the anode of the electrochemical cells described herein include, but are not limited to, lithium metal, such as lithium foil or lithium deposited on a conductive substrate, and lithium alloys (e.g., lithium-aluminum alloys and lithium-tin alloys). Methods for disposing the anode material (e.g., alkali metal anodes, such as lithium) on a substrate may include methods such as thermal evaporation, sputtering, jet vapor deposition, and laser ablation. Alternatively, when the anode comprises a lithium foil, or a lithium foil and a substrate, they may be attached together by lamination as known in the art to form the anode.

[0460] In one embodiment, the electroactive lithium-containing material of the anode active layer comprises greater than 50% lithium by weight. In another embodiment, the electroactive lithium-containing material of the anode active layer comprises greater than 75% lithium by weight. In yet another embodiment, the electroactive lithium-containing material of the anode active layer comprises greater than 90% lithium by weight. Additional materials and configurations suitable for use in the anode are described, for example, in U.S. Patent Application Publication No. 2010 / 0035128, entitled "Application of Force in Electrochemical Cells," filed Aug. 4, 2009, to Scordilis-Kelley et al., which is incorporated herein by reference in its entirety for all purposes.

[0461] The cathode of the electrochemical cell described herein may include various cathode active materials. As used herein, the term "cathode active material" refers to any electrochemically active species associated with the cathode. Suitable electroactive materials for use as cathode active materials in the cathode of the electrochemical cell of some embodiments include, but are not limited to, one or more metal oxides, one or more intercalation materials, electroactive transition metal chalcogenides, electroactive conductive polymers, sulfur, carbon, and / or combinations thereof.

[0462] In some embodiments, the cathode active material comprises one or more metal oxides. In some embodiments, an intercalation cathode (e.g., a lithium intercalation cathode) may be used. Non-limiting examples of suitable materials that may intercalate the ions (e.g., alkali metal ions) of the electroactive material include metal oxides, titanium sulfide, and iron sulfide. In some embodiments, the cathode is an intercalation cathode that includes a lithium transition metal oxide or a lithium transition metal phosphate. Further examples include Li x CO2 (e.g., Li 1.1 CO2), Li x NiO2, Li x MnO2, Li x Mn2O4 (e.g., Li 1.05 Mn2O4), Li x CoPO4, Li x MnPO4, LiCо x Ni (1-x) O2, and LiCо x Ni y Mn (1-x-y) O2 (e.g., LiNi 1 / 3 Mn 1 / 3 C 1 / 3 O2, LiNi 3 / 5 Mn 1 / 5 Cо1 / 5O2, LiNi 4 / 5 Mn 1 / 10 C 1 / 10 O2, LiNi 1 / 2 Mn 3 / 10 C 1 / 5O2). x may be 0 or greater and 2 or less. When the electrochemical cell is fully discharged, x is typically 1 or greater and 2 or less, and when the electrochemical cell is fully charged, x is less than 1. In some embodiments, a fully charged electrochemical cell may have a value of x that is 1 or greater and 1.05 or less, 1 or greater and 1.1 or less, or 1 or greater and 1.2 or less. Further examples include (0 <x≦1)であるLi x NiPO4, (x+y=2) LiMn x Ni y O4 (e.g., LiMn 1.5 Ni 0.5 O4), (x+y+z=1) LiNi x C y Al z O2, LiFePO4, and combinations thereof. In some embodiments, the electroactive material in the cathode comprises a lithium transition metal phosphate (e.g., LiFePO4), which in some embodiments can be substituted with a borate and / or a silicate.

[0463] As previously mentioned, in some embodiments, the cathode active material comprises one or more chalcogenides. As used herein, the term "chalcogenide" refers to a compound containing one or more of the elements oxygen, sulfur, and selenium. Examples of suitable transition metal chalcogenides include, but are not limited to, electroactive oxides, sulfides, and selenides of transition metals selected from the group consisting of Mn, V, Cr, Ti, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, and Ir. In one embodiment, the transition metal chalcogenide is selected from the group consisting of electroactive oxides of nickel, manganese, cobalt, and vanadium, and electroactive sulfides of iron. In one embodiment, the cathode comprises one or more of the following materials: manganese dioxide, iodine, silver chromate, silver oxide and vanadium pentoxide, copper oxide, copper oxyphosphate, lead sulfide, iron sulfide, lead bismuthate, bismuth trioxide, cobalt dioxide, copper chloride, manganese dioxide, and carbon. In another embodiment, the cathode active layer comprises an electroactive conductive polymer. Examples of suitable electroactive conductive polymers include, but are not limited to, electroactive and electronically conductive polymers selected from the group consisting of polypyrrole, polyaniline, polyphenylene, polythiophene, and polyacetylene. Examples of conductive polymers include polypyrroles, polyanilines, and polyacetylenes.

[0464] In some embodiments, the electroactive material for use as a cathode active material in the electrochemical cells described herein comprises an electroactive sulfur-containing material. "Electroactive sulfur-containing material" as used herein refers to a cathode active material that contains elemental sulfur in any form, and the electrochemical activity includes the oxidation or reduction of sulfur atoms or moieties. The nature of the electroactive sulfur-containing material useful in the practice of some embodiments can vary widely, as is known in the art. For example, in one embodiment, the electroactive sulfur-containing material comprises elemental sulfur. In another embodiment, the electroactive sulfur-containing material comprises a mixture of elemental sulfur and a sulfur-containing polymer. Thus, suitable electroactive sulfur-containing materials include, but are not limited to, elemental sulfur, and organic materials (which may or may not be polymeric) that contain sulfur and carbon atoms. Suitable organic materials include those that further contain heteroatoms, conductive polymer segments, composites, and conductive polymers.

[0465] In some embodiments, the electroactive sulfur-containing material of the cathode active layer comprises more than 50% sulfur by weight. In other embodiments, the electroactive sulfur-containing material comprises more than 75% sulfur by weight. In yet other embodiments, the electroactive sulfur-containing material comprises more than 90% sulfur by weight.

[0466] The cathode active layer of some embodiments may comprise about 20-100% by weight of electroactive cathode material (e.g., as measured after a suitable amount of solvent has been removed from the cathode active layer and / or after the layer has been properly cured). In one embodiment, the amount of electroactive sulfur-containing material in the cathode active layer ranges from 5-30% by weight of the cathode active layer. In another embodiment, the amount of electroactive sulfur-containing material in the cathode active layer ranges from 20% to 90% by weight of the cathode active layer.

[0467] Additional materials suitable for use in the cathode and suitable methods for manufacturing the cathode are described, for example, in U.S. Pat. No. 5,919,587, filed May 21, 1997, entitled "Novel Composite Cathodes, Electrochemical Cells Comprising Novel Composite Cathodes, and Processes for Fabricating Same," and U.S. Patent Application Publication No. 2010 / 0035128, filed August 4, 2009, to Scordilis-Kelley et al., each of which is incorporated herein by reference in its entirety for all purposes.

[0468] A variety of electrolytes may be used in connection with the electrochemical cells described herein. In some embodiments, the electrolyte may include a non-solid electrolyte, which may or may not be incorporated into the porous separator. As used herein, the term "non-solid" is used to refer to a material that cannot withstand static shear stress and in which the non-solid experiences a continuous and permanent distortion upon application of shear stress. Examples of non-solids include, for example, liquids, deformable gels, and the like.

[0469] The electrolytes used in the electrochemical cells described herein function as a medium for the storage and transport of ions, and in the particular case of solid and gel electrolytes, these materials may also function as a separator between the anode and cathode. Any liquid, solid, or gel material capable of storing and transporting ions and facilitating the transport of ions (e.g., lithium ions) between the anode and cathode may be used. Exemplary materials suitable for use in the electrolyte are described, for example, in U.S. Patent Application Publication No. 2010 / 0035128, to Scordilis-Kelley et al., entitled "Application of Force in Electrochemical Cells," filed Aug. 4, 2009, which is incorporated herein by reference in its entirety for all purposes.

[0470] U.S. Application No. 16 / 670,905, filed October 31, 2019, and entitled "SYSTEM AND METHOD FOR OPERATING A RECARGEABLE ELECTROCHEMICAL CELL OR BATTERY," is hereby incorporated by reference in its entirety for all purposes.

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Claims

1. an electrochemical cell, and at least one controller configured to control the cell such that the cell is charged over a first state of charge range having a width of at least 20%; Equipped with an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spanning at least 2% of the first state of charge range, and the second portion spanning at least 2% of the first state of charge range; The electrochemical cell management system, wherein the first portion occurs before the second portion.

2. an electrochemical cell, and at least one controller configured to control the cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 90% and then charged over a second state of charge range; Equipped with 11. An electrochemical cell management system, wherein an average charge rate in said first state of charge range is at most 0.5 times an average charge rate in said second state of charge range.

3. an electrochemical cell, and at least one controller configured to control the cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 40%, then over a second state of charge range having a width of at least 2%, and then over a third state of charge range having a width of at least 2%; Equipped with a charging rate in the first state of charge range is lower than an average charging rate in the second state of charge range; The electrochemical cell management system wherein an average charge rate in the second state of charge range is less than an average charge rate in a third state of charge range.

4. the at least one controller is configured to control the cell such that the cell is discharged over a second state of charge range having an amplitude of at least 2% and at most 90%, and then over a third state of charge range having an amplitude of at least 2%; 10. The electrochemical cell management system of claim 1, wherein an average discharge rate in said second state of charge range is at least twice as high as an average discharge rate in said third state of charge range.

5. at least one controller configured to control the cell such that the cell is discharged over a second state of charge range having a width of at least 2% and at most 90%, then over a third state of charge range having a width of at least 2%, and then over a fourth state of charge range having a width of at least 2%; an average discharge rate in the second state of charge range is greater than an average discharge rate in the third state of charge range; 2. The electrochemical cell management system of claim 1, wherein an average discharge rate in said third state of charge range is greater than an average discharge rate in said fourth state of charge range.

6. The electrochemical cell management system of any one of claims 1 to 5, wherein the cells comprise a lithium metal electrode active material.

7. controlling the electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 20%; Including, an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spanning at least 2% of the first state of charge range and the second portion spanning at least 2% of the first state of charge range; The method of electrochemical cell management, wherein the first portion occurs before the second portion.

8. controlling the electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 90% and then charged over a second state of charge range; Including, 11. A method of electrochemical cell management, wherein an average charge rate in said first state of charge range is at most 0.5 times an average charge rate in said second state of charge range.

9. controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 40%, then over a second state of charge range having a width of at least 2%, and then over a third state of charge range having a width of at least 2%. Including, a charging rate in the first state of charge range is lower than an average charging rate in the second state of charge range; The method of claim 1, wherein an average charge rate in the second state of charge range is less than an average charge rate in a third state of charge range.

10. When executed by at least one processor, the at least one processor controlling the electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 20%; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: an average charge rate in a first portion of the first state of charge range is lower than an average charge rate in a second portion of the first state of charge range; the first portion spanning at least 2% of the first state of charge range and the second portion spanning at least 2% of the first state of charge range; At least one computer readable storage medium, wherein the first portion occurs before the second portion.

11. When executed by at least one processor, the at least one processor controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 90% and then charged over a second state of charge range; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: At least one computer readable storage medium, wherein an average charge rate in the first state of charge range is at most 0.5 times an average charge rate in the second state of charge range.

12. When executed by at least one processor, the at least one processor controlling an electrochemical cell such that the cell is charged over a first state of charge range having a width of at least 2% and at most 40%, then over a second state of charge range having a width of at least 2%, and then over a third state of charge range having a width of at least 2%. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: a charging rate in the first state of charge range is lower than an average charging rate in the second state of charge range; At least one computer readable storage medium, wherein an average charge rate in the second state of charge range is lower than an average charge rate in the third state of charge range.

13. An electrochemical cell; monitoring at least one characteristic of the cell indicative of a loss of lithium in the cell; Controlling a charge or discharge rate of the cell based on at least one monitored characteristic of the cell. At least one controller configured to An electrochemical cell management system comprising:

14. monitoring at least one characteristic of the cell indicative of a loss of lithium in the cell; and controlling a charge rate or a discharge rate of the cell based on at least one monitored characteristic of the cell. A method for managing an electrochemical cell comprising:

15. an electrochemical cell, and at least one controller configured to control the cells such that the cells are discharged and then charged; Equipped with 1. An electrochemical cell management system, comprising: for at least a portion of a discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during said portion of the discharge is at least twice an average charge rate during at least a portion of the charge.

16. controlling an electrochemical cell so that the cell is discharged and then charged; Including, 1. A method of managing an electrochemical cell, wherein for at least a portion of a discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during said portion of the discharge is at least twice an average charge rate during at least a portion of the charge.

17. An electrochemical cell; Analyzing the cycle history of the cell; When a threshold state of charge is reached during discharge, the discharge rate of the cell is increased to at least twice the average charge rate of at least a portion of at least one cycle in the cycle history. at least one controller configured to control the cells such that Equipped with The electrochemical cell management system, wherein the threshold state of charge has a value less than or equal to 60%.

18. analyzing the cycle history of the cell; and controlling the cell such that upon reaching a threshold state of charge during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least a portion of at least one cycle of a cycle history; Including, The method of claim 1, wherein said threshold state of charge has a value of 60% or less.

19. An electrochemical cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least a portion of the terminated charging step. at least one controller configured to control the cells such that Equipped with An electrochemical cell management system, wherein the ending state of charge has a value of 60% or less.

20. At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least a portion of the terminated charging step. To control the electrochemical cell so that Including, A method of electrochemical cell management, wherein the ending state of charge has a value of 60% or less.

21. An electrochemical cell; Analyzing the cycle history of the cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history over a state of charge range having a width of at least 1%. Controlling the Cell It is configured as follows: At least one controller Equipped with The electrochemical cell management system, wherein said ending state of charge has a value of 60% or less.

22. Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history over a state of charge range having a width of at least 1%. Controlling the cell. Including, A method of managing an electrochemical cell, wherein said ending state of charge has a value of 60% or less.

23. Electrochemical cell and Analyzing the cycle history of the cell; Controlling the cell to discharge the cell to meet the criteria if none of the most recent cycles meet the criteria for the most recent number of cycles in the cycle history. It is configured as follows: At least one controller Equipped with the criteria include discharging the cell at a discharge rate that is at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; 1. An electrochemical cell management system, the number of most recent cycles being at least five cycles.

24. Analyzing the cycle history of the electrochemical cell; and controlling the cell to discharge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; Including, the criteria includes discharging the cell at a discharge rate that is at least twice the average charge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; The method of claim 1, wherein the number of most recent cycles is at least 5 cycles.

25. An electrochemical cell; Analyzing the cycle history of the cell; Controlling the cell to discharge the cell to meet the criteria if none of the most recent cycles meet the criteria for a most recent number of cycles in the cycle history. It is configured as follows: At least one controller Equipped with the criteria including discharging the cell at a discharge rate that is at least twice the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; said discharge rate being at most four times the maximum recommended continuous discharge rate; 1. An electrochemical cell management system, the number of most recent cycles being at least five cycles.

26. Analyzing the cycle history of the electrochemical cell; and controlling the cell to discharge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; Including, the criteria including discharging the cell at a discharge rate that is at least twice the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; said discharge rate being at most four times the maximum recommended continuous discharge rate; The method of claim 1, wherein the number of most recent cycles is at least 5 cycles.

27. An electrochemical cell; Analyzing the cycle history of the cell; controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; It is configured as follows: At least one controller Equipped with the criteria include charging the cell at a charge rate that is at most 0.5 times the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; 1. An electrochemical cell management system, the number of most recent cycles being at least five cycles.

28. Analyzing the cycle history of the electrochemical cell; and controlling the cell to charge the cell to meet the criteria if no cycles meet the criteria among the most recent cycles for a most recent number of cycles in the cycle history; Including, the criteria include charging the cell at a charge rate that is at most 0.5 times the average discharge rate of any cycle in the most recent cycles over a state of charge range that is at least 2% and at most 60% wide; The method of claim 1, wherein the number of most recent cycles is at least 5 cycles.

29. An electrochemical cell; Analyzing the cycle history of the cell; controlling the cell such that when a threshold state of charge is reached during discharge, the discharge rate of the cell is increased to at least twice the average charge rate of at least one cycle in the cycle history; It is configured as follows: At least one controller Equipped with The electrochemical cell management system, wherein the threshold state of charge has a value less than or equal to 60%.

30. Analyzing the cycle history of the electrochemical cell; and controlling the cell such that upon reaching a threshold state of charge during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least one cycle in a cycle history; Including, The method of claim 1, wherein said threshold state of charge has a value of 60% or less.

31. An electrochemical cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of the terminated charging step. The cell is controlled so that It is configured as follows: At least one controller Equipped with The electrochemical cell management system, wherein said ending state of charge has a value of 60% or less.

32. At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of the terminated charging step. To control the electrochemical cell so that Including, A method of managing an electrochemical cell, wherein said ending state of charge has a value of 60% or less.

33. An electrochemical cell; Analyzing the cycle history of the cell; At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycle history; Controlling the Cell It is configured as follows: At least one controller Equipped with The electrochemical cell management system, wherein said ending state of charge has a value of 60% or less.

34. Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least one cycle in the cycle history. Controlling the cell. Including, A method of managing an electrochemical cell, wherein said ending state of charge has a value of 60% or less.

35. an electrochemical cell, and at least one controller configured to control the cells such that the cells are discharged and then charged over a state of charge range having a width of at least 2% and at most 60%. Equipped with 13. An electrochemical cell management system, wherein the discharge rate during said discharging is at least twice the average charge rate during said charging.

36. Controlling an electrochemical cell so that the cell is discharged and then charged over a state of charge range having a width of at least 2% and at most 60%. Including, 11. A method of managing an electrochemical cell, wherein the discharge rate during the discharging is at least twice the average charge rate during the charging.

37. An electrochemical cell; determining whether a fast charge request has been received; If no fast charge request is received, control the cell such that the cell is charged through a first state of charge range having a width of at least 2% and at most 60% and then through a second state of charge range. It is configured as follows: At least one controller Equipped with 11. An electrochemical cell management system, wherein a charge rate in said first state of charge range is at most 0.5 times an average charge rate in said second state of charge range.

38. determining whether a fast charging request has been received; and controlling the electrochemical cell to be charged through a first state of charge range having a width of at least 2% and at most 60% and then to be charged through a second state of charge range when no fast charge request is received; Including, 11. A method of electrochemical cell management, wherein the charge rate in said first state of charge range is at most 0.5 times the average charge rate in said second state of charge range.

39. Electrochemical cell and controlling the cell such that the cell is discharged and then immediately charged over a first state of charge range having a width of at least 2% and at most 60%, and a future charging schedule is set such that a criterion is met by the end of four cycles that go through the first state of charge range; Schedule future charging It is configured as follows: At least one controller Equipped with 11. An electrochemical cell management system comprising: the cell being charged in a second state of charge range such that a charge rate in the first state of charge range is at most 0.5 times an average charge rate in the second state of charge range.

40. controlling the electrochemical cell such that the cell is discharged and then immediately charged over a first state-of-charge range having a width of at least 2% and at most 60%, and setting a future charging schedule to meet the criteria by the end of four cycles that go through the first state-of-charge range; and executing said future charging schedule; Including, 11. A method of electrochemical cell management, wherein the criteria includes the cell being charged over a second state of charge range such that the charge rate in the first state of charge range is at most 0.5 times the average charge rate in the second state of charge range.

41. When executed by at least one processor, the at least one processor monitoring at least one characteristic of the cell indicative of a loss of lithium in the cell; and controlling a charge rate or a discharge rate of the cell based on at least one monitored characteristic of the cell. At least one computer readable storage medium encoded with executable instructions to perform an electrochemical cell management method comprising:

42. When executed by at least one processor, the at least one processor controlling an electrochemical cell so that the cell is discharged and then charged; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: At least one computer readable storage medium, wherein for at least a portion of a discharge covering a first state of charge range having a width of at least 2% and at most 60%, an average discharge rate during the portion of the discharge is at least twice an average charge rate during at least a portion of the charge.

43. When executed by at least one processor, the at least one processor analyzing the cycle history of the cell; and controlling the cell such that when a threshold state of charge is reached during discharge, a discharge rate of the cell is increased to at least twice an average charge rate of at least a portion of at least one cycle of a cycle history; At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: At least one computer readable storage medium, wherein the threshold state of charge has a value less than or equal to 60%.

44. When executed by at least one processor, the at least one processor At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged over a state-of-charge range having a width of at least 1% at a discharge rate that is at least twice the average charge rate of at least a portion of the terminated charging step. Controlling the cell. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: At least one computer readable storage medium, wherein the ending state of charge has a value of 60% or less.

45. When executed by at least one processor, the at least one processor Analyzing the cycle history of the electrochemical cell; and At the final charge state, the charging process is terminated and discharging is initiated; During the initiated discharge, the cell is discharged at a discharge rate that is at least twice the average charge rate of at least a portion of at least one cycle of the cycle history over a state of charge range having a width of at least 1%. Controlling the cell. At least one computer readable storage medium encoded with executable instructions for performing an electrochemical cell management method, comprising: At least one computer readable storage medium, wherein the ending state of charge has a value of 60% or less.

46. an electrochemical cell, and During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. and configured to control the cell so that At least one controller An electrochemical cell management system comprising:

47. During the charging step, the electrochemical cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. and controlling the cell so that A method for managing an electrochemical cell comprising:

48. When executed by at least one processor, the at least one processor During the charging step, the electrochemical cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a first discharge rate that is at least twice the first or second charge rate over a third state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate that is less than twice the first or second charge rate over a fourth state of charge range having a width of at least 2%. To control the electrochemical cell so that At least one computer readable storage medium encoded with executable instructions to perform an electrochemical cell management method comprising:

49. an electrochemical cell, and During the discharging step, the cell is discharged at a first discharge rate over a first state of charge range having an amplitude of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; The second discharge rate is less than twice the corresponding charge rate. and configured to control the cell so that At least one controller An electrochemical cell management system comprising:

50. During the discharging step, the electrochemical cell is discharged at a first discharge rate over a first state of charge range having an amplitude of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; the second discharge rate being less than twice the corresponding charge rate; Controlling the cell.

23. A method for managing an electrochemical cell comprising:

51. When executed by at least one processor, the at least one processor During the discharging step, the electrochemical cell is discharged at a first discharge rate over a first state of charge range having a width of at least 2%; During the discharging step, the cell is discharged at a second discharge rate over a second state of charge range having a width of at least 2%; the first discharge rate is at least twice the corresponding charge rate; and the second discharge rate being less than twice the corresponding charge rate; Controlling an electrochemical cell At least one computer readable storage medium encoded with executable instructions to perform an electrochemical cell management method comprising:

52. an electrochemical cell, and During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; the first charge rate is at most 0.5 times the corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. and configured to control the cell so that At least one controller An electrochemical cell management system comprising:

53. During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; said first charge rate being at most 0.5 times a corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. Controlling the cell. A method for managing an electrochemical cell comprising:

54. When executed by at least one processor, the at least one processor During the charging step, the cell is charged at a first charge rate over a first state of charge range having a width of at least 2%; During the charging step, the cell is charged at a second charge rate over a second state of charge range having a width of at least 2%; said first charge rate being at most 0.5 times a corresponding discharge rate; The second charge rate is greater than 0.5 times the corresponding discharge rate. Controlling an electrochemical cell At least one computer readable storage medium encoded with executable instructions to perform an electrochemical cell management method comprising:

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