System and method for operating rechargeable electrochemical cell or battery

Abstract

To provide at least one controller electrochemical cell management system configured to control an electrochemical cell and an electrochemical cell management method.SOLUTION: In an electrochemical cell management system including an electrochemical cell and at least one controller that controls the cell to charge the cell, for at least a portion of a charge cycle, at a charge rate or charge current that is lower than a discharge rate or discharge current of at least a portion of the previous discharge cycle, an electrochemical cell management method includes monitoring an electrochemical cell and at least one characteristic of the cell, and inducing discharge and / or controlling a charge rate or charge current of the cell on the basis of the at least one characteristic of the cell.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to the management of charging and discharging of electrochemical cells and related systems. [Background technology]

[0002] Historically, batteries have not been able to compete successfully with established power sources such as the internal combustion engine in various industries, such as automotive, in part because battery users have been dissatisfied with the lifespan and performance of batteries traditionally offered. Summary of the Invention

[0003] Disclosed herein are embodiments relating to electrochemical cell charge / discharge management and related systems. The subject matter of the invention in some cases includes interrelated products, alternative solutions to a particular problem, and / or a number of different applications of one or more systems and / or articles.

[0004] Some embodiments are directed to an electrochemical cell management system comprising: an electrochemical cell; and at least one controller configured to control the cell such that, for at least a portion of a charge cycle, the cell is charged at a charge rate or charge current that is lower than a discharge rate or discharge current of at least a portion of a previous discharge cycle.

[0005] Some embodiments are directed to an electrochemical cell management system comprising: an electrochemical cell; and at least one controller configured to monitor at least one characteristic of the cell, the at least one characteristic including at least a portion of a discharge history of the cell and at least one of at least one morphological characteristic of the cell; and the controller directs discharge of the cell and / or controls a charge rate or charge current of the cell based on the at least one characteristic of the cell.

[0006] Some embodiments are directed to an electrochemical cell management system comprising an electrochemical cell and at least one controller configured to induce discharging of the cell before and / or after a charging process of the cell.

[0007] Further embodiments are directed to a method of electrochemical cell management that may include controlling an electrochemical cell such that, for at least a portion of a charge cycle, the cell is charged at a charge rate or charge current that is lower than a discharge rate or discharge current of at least a portion of a previous discharge cycle.

[0008] Further embodiments are directed to methods of electrochemical cell management, which may include inducing a discharge of the electrochemical cell before and / or after a charging step of the electrochemical cell.

[0009] Some embodiments are directed to a method of electrochemical cell management that may include monitoring at least one characteristic of the cell, which may include at least one of at least a portion of the discharge history of the cell and at least one of at least one morphological characteristic of the cell, and directing discharge of the cell and / or controlling a charge rate or charge current of the cell based on the at least one characteristic of the cell.

[0010] 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]

[0011] 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 the drawings, each identical or nearly identical component shown is typically represented by a single numeral. For clarity, not every component is necessarily labeled in every figure, and not every figure is necessarily every component of each embodiment of the present invention shown, unless it is necessary to enable a person skilled in the art to understand the invention. In the drawings: [Figure 1A] FIG. 1 is a block diagram illustrating an exemplary electrochemical cell management system, according to some embodiments. [Figure 1B] 1 is a current-time graph illustrating an exemplary charging scheme of an exemplary electrochemical cell management system, according to some embodiments. [Figure 1C] 1 is a current-time graph illustrating an exemplary charging scheme of an exemplary electrochemical cell management system, according to some embodiments. [Figure 1D] 1 is a current-time graph illustrating an exemplary charging scheme of an exemplary electrochemical cell management system, according to some embodiments. [Figure 1E] FIG. 1 is a circuit diagram illustrating an exemplary simplified electrochemical cell model, according to some embodiments. [Figure 1F] FIG. 1 is a block diagram illustrating an exemplary battery management system, according to some embodiments. [Diagram 2] FIG. 2 is a block diagram illustrating a representative battery pack, according to some embodiments. [Figure 3A] FIG. 1 is a block diagram illustrating an exemplary battery management system, according to some embodiments. [Figure 3B] FIG. 2 is a block diagram illustrating a representative set of such cells and corresponding components, according to some embodiments. [Figure 3C] 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 3D] FIG. 1 is a cross-sectional schematic diagram of an electrochemical cell according to some embodiments. [Figure 4A] 4 is a flow chart illustrating an exemplary process for controlling the charge rate or charge current of the cell, according to some embodiments. [Figure 4B] 4 is a flow chart illustrating a further exemplary process for controlling the charge rate or charge current of the cell, according to some embodiments. [Figure 4C] 4 is a flow chart illustrating exemplary steps for inducing discharge of the cell, according to some embodiments. [Figure 4D] 10 is a flow chart illustrating further exemplary steps for inducing discharge of the cell, according to some embodiments. [Figure 5A] 4 is a flow chart illustrating an exemplary process for monitoring a characteristic of, inducing discharge of, or controlling the charge rate or charge current of, the cell, according to some embodiments. [Figure 5B] 4 is a flow chart illustrating further exemplary steps for monitoring the cell characteristics, inducing discharge, or controlling the charge rate or charge current of the cell, according to some embodiments. [Figure 6A] 4 is a flowchart illustrating an exemplary process for discharging the set of cells of a battery, according to some embodiments. [Figure 6B] 4 is a flowchart illustrating a further exemplary process for discharging the set of cells of a battery, according to some embodiments. [Figure 6C] 4 is a flowchart illustrating an exemplary process for controlling a battery pack, according to some embodiments. [Figure 6D] 4 is a flowchart illustrating a further exemplary process for controlling a battery pack, according to some embodiments. [Figure 7A] 1 is a chart illustrating an exemplary discharge profile according to some embodiments. [Figure 7B] 1 is a chart illustrating an exemplary full discharge profile, according to some embodiments. [Figure 7C]1 is a chart illustrating an exemplary battery cycle life according to some embodiments. [Figure 8] FIG. 1 is a block diagram illustrating a representative computing system that can be used to implement certain aspects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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 their batteries to charge at a rate higher than the rate at which they discharge (e.g., 30 minutes to charge and 4 hours to discharge) for a variety of reasons, such as to reduce the inconvenience of waiting for a charge to use the battery.

[0013] 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 as used herein, 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.

[0014] 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.

[0015] 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.

[0016] 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), can be significantly improved by employing a high ratio of discharge rate to charge rate. Furthermore, the inventors recognize and understand that these ratios can be employed by providing a cell and / or battery management system that controls the cells to provide such ratios.

[0017] For example, some embodiments are directed to the cell management system controlling the cell such that for at least a portion of a 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 a previous discharge cycle. As another example, some embodiments are directed to the cell management system monitoring at least one characteristic of the cell (such as a portion of the cell's discharge history or a morphological characteristic of the cell) and inducing discharge or controlling the charge rate or charge current of the cell based on the characteristic. As a further example, some embodiments are directed to the cell management system inducing discharge of the cell immediately before and / or immediately after (or at some earlier time) a charging step of the cell while the cell is connected to a charging device.

[0018] In some embodiments, inducing a discharge of the cell may include discharging the cell in response to a command from a controller. In some embodiments, the induced discharge may be at a rate higher than an average discharge rate in the discharge history of the cell. In some embodiments, the induced discharge may include discharging the cell without powering a load to perform a function, which may be done for the purpose of changing the overall average discharge rate of the cell and / or the average of a current charge / discharge cycle. In some embodiments, the induced discharge may be performed during a charge cycle that may include multiple charge steps such as those shown in FIGS. 1B-1D.

[0019] Some embodiments, such as those having multiple cells, are directed to a battery management system that multiplexes the cells so that they can be charged all at once (or discharged simultaneously) and discharged individually or in smaller sets. This can result in an actual ratio of charge rate to discharge 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 uniform current distribution may also improve cycle life.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] In some embodiments, the charging step is carried out 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.

[0030] 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, as 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.

[0031] 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 of time is calculated as follows:

number

number

[0032] 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

[0033] 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, the controller may be aware of these factors because it can measure (such as via sensor 116) parameters or characteristics that can be used to determine each of them. The 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.

[0034] 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.

[0035] 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. For example, the overall charging scheme may be similar to FIG. 1B, where the cell is discharged for a time DT and charged for a time CT. As shown in FIG. 1B, the cell is discharged for a short period of time, then fully charged at a lower current than for discharging, then discharged for a short period of time, and topped off with a charge.

[0036] 1C, which shows the cell being discharged for a time DT, charged for a time CT at a lower current than when it was discharged, discharged again for a time DT, charged again for a time CT, and discharged again for a time DT. In some embodiments, CT may correspond to just over half of the total recharge capacity of the cell, and CT may be a relatively short time determined by the SOH of the cell.

[0037] In some embodiments, the controller may induce a discharge of the cell, such as any of the discharges shown in Figures 1B-1D. For example, the controller may induce a discharge of the cell just prior to the start of the charging process of the cell, in the form shown in Figures 1B-1C. In some embodiments, the controller may cause such an induced discharge, or any of those described herein, based on characteristics of the cell. Alternatively, the controller may perform or cause any of these induced discharges based on other criteria, as described herein. In some embodiments, the cell may remain connected to a charging device during both the induced discharge and the ambient charging process.

[0038] The inventors recognize and understand that inducing discharge at times described herein may improve the performance and cycle life of the cell since the ratio of discharge to charge rate or charge current may approach a desired asymmetric range, such as 2:1 or 4:1. For example, if the cell is discharged at a lower rate or current than the charge, such induced discharge may be performed at a much higher rate or current to improve the ratio, especially during a portion of the charge / discharge cycle. In some embodiments, the controller may induce discharge of the cell at a first rate or first current through at least a threshold capacity of the cell (e.g., at least 5%, at least 10%, or at least 15% of the discharge or recharge capacity of the cell) prior to (e.g., immediately before or less than 10 minutes after) the start of a charging step of the cell that charges the cell slower than a first rate or first current. In some embodiments, the controller may direct the discharge at a rate or current that is higher than the average discharge rate or average discharge current of the previous (such as most recent) discharge cycle and / or discharge step, or at a rate that is higher than the average charge rate or average charge current of the previous (such as most recent) charge cycle and / or charge step.

[0039] Alternatively or additionally, the controller may induce a discharge of the cell during (e.g., at the end of) a discharge cycle and / or discharge step of the cell. In some embodiments, the controller may induce such a discharge at a rate or current higher than the existing discharge or the average discharge of a previous discharge cycle. For example, a discharge may be induced at 400 mA, whereas the average discharge current of the most recent discharge cycle was 100 mA. Other examples are described below in Tables 1-4.

[0040] The controller may alternatively or additionally induce a discharge at the end of a charge cycle and / or a discharge step of the cell, in a manner such as that shown in Figure 1C. In some embodiments, inducing a discharge at the end of a cycle may include inducing a discharge within the last 5% (or 10% or 15%) of the cycle.

[0041] The inventors have recognized and appreciated that inducing a discharge of the cell in some or all of the situations described herein may reduce physical damage to the cell, such as the formation and extension of pits (e.g., at the anode of the cell), and may even smooth and reverse some previous damage to the cell.

[0042] The overall charging scheme may look similar to Figure 1D, which, as a further example, shows the cell first being charged for a time PCT, then discharged for CT, and finally fully charged for CT. The inventors recognize and appreciate that if the cell is determined to be fully discharged, as may be the case for the cell of Figure 1D, it would not be advantageous to begin with a discharge cycle and / or discharge process.

[0043] 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

[0044] 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.

[0045] 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 can be measured by directly monitoring the pressure and / or size change of the cell. These are further inputs that can be used in determining SOC and SOH, and can also be used in determining how to charge the cell.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] FIG. 1F 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. 1F, 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).

[0050] According to some embodiments, the battery or cells may include at least one lithium metal cell. Additionally, each battery or cell (e.g., 120-150) may 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, two or more cell sets are included in each battery, such as 121-122. Additionally, 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. Additionally, each cell (either in the battery, all the batteries in the battery pack, or in the set of cells) or 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.

[0051] In some embodiments, a multiplexing switch device (e.g., 112) may include an array of switches as further described in connection with Figures 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 use the multiplexing switch device to selectively discharge the cells or sets of cells based on at least one criterion.

[0052] 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 the next highest voltage or some other indicator of next strongest. 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.

[0053] Alternatively or additionally, the criteria may be context sensitive, such as by considering 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 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.

[0054] In some embodiments, the function may have parameters such as any one or more of the following: accumulated capacity over several connections between a load and the set of cells, delivered discharge capacity at a connection, current of the set of cells, voltage of the set of cells and / or at least one other set of cells, discharge end voltage (or discharge cut-off 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, rate of voltage fading 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 the physical enclosure of the cells, which may indicate the capacity of the cells, discussed further 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% (e.g., 95%) of the set nominal capacity.

[0055] In some embodiments, a sensor (e.g., 116) may measure any of the parameters of the criteria and / or the function. For example, a sensor may include a current sensor that measures the current in amperes of a given set of said cells. It should be understood that the criteria may be multiple or singular and may relate to the set of said cells currently discharging and / or may determine the next set of said cells.

[0056] In some embodiments, a controller (e.g., 114) may include one or more processors, which may be of any complexity appropriate to 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.

[0057] In some embodiments, the controller may use a multiplexing switch device to selectively discharge and charge the set of cells at different, programmable rates. For example, the controller may use a multiplexing switch device to selectively discharge the 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., discharging is twice as fast as charging). Alternatively or additionally, the first rate of discharge may be at least four times higher than the second rate at which the set of cells is charged (i.e., discharging is four times as fast as charging). 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.

[0058] According to some embodiments, the controller may overlap the discharge of a set of the cells in time. For example, a given set of cells may begin discharging before another set of the cells stops discharging. In some embodiments, the controller may continue to supply power from the set of cells during switching between different sets. The inventors have recognized and understood that this overlap in time of discharge and power continuation may maintain the power requirements of the load even during transition between different cells of the set of cells, which may further improve 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.

[0059] 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.

[0060] Alternatively or additionally, the controller may use a multiplexing switch device (eg, 112) to connect the set of cells to a load in a topology adopted or required by the load.

[0061] In some embodiments, the controller may use a multiplexing switch device (e.g., 112) to isolate a single set of the cells for discharge while other sets of the 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 the cells or a single cell for discharge while other sets of the cells are not discharging. For a given cycle, according to some embodiments, each cell may be discharged once before any of the cells are discharged a second time (e.g., sequential discharge is used, but is not limited to such embodiments).

[0062] With regard to charging, in some embodiments, the controller may use a multiplexing switch device to charge the set of cells and / or the cells within a set in parallel, for example, all the cells in the block of cells, battery, or battery may be charged in parallel at one-quarter the discharge rate.

[0063] FIG. 2 illustrates an exemplary battery pack 210. In some embodiments, the exemplary battery pack 210 may include a switching control system (e.g., 218) and one or more batteries (e.g., 120, 130, 140, 150, etc.). Although only a single switching control system 218 and four batteries 120-150 are shown in FIG. 2, 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 the control and switching described herein may be distributed across any suitable number of devices (e.g., switches, controllers, etc.).

[0064] In some embodiments, the switching control system (e.g., 218) may include an array of switches, which may include a controller, as further described in connection with FIG. 3A and FIG. 3B below. Additionally, the switching control system may be individually connected to each set of cells and / or to each cell of the battery, as described in connection with FIG. 1F 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 predetermined 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 a function. In some embodiments, the basis for the control may not include the number of previous discharge cycles of the set of cells.

[0065] 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 1F above.

[0066] It should be understood that any of the components of the exemplary system 100 or the exemplary battery pack 210 may be implemented using any suitable combination of hardware and / or software components. As such, the various components may be considered as controllers that can employ any suitable collection of hardware and / or software components to perform the described functions.

[0067] 3A illustrates an exemplary battery management system 300. In some embodiments, the exemplary system 300 can include any suitable number of multi-cell blocks (e.g., 321-325), a battery cell block arrangement and balance switch configuration (e.g., 326), a battery management microcontroller (e.g., 327), a battery system interface (e.g., 328), battery power terminals (e.g., 329), and sensors (e.g., 360). The multi-cell blocks may be connected to the battery cell block arrangement and balance switch configuration. The multi-cell blocks may also be connected to the battery management microcontroller.

[0068] In some embodiments, the battery cell block arrangement and balancing switch configuration may include switch multiplexing, which may connect the cell blocks (e.g., 321-325) in series, parallel, series / parallel, or other suitable topology necessary to meet the voltage and current requirements of a given application or load.

[0069] 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., 328), 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.

[0070] 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 a current sensor that measures the current in amperes of a given set of cells.

[0071] Although the battery cell block arrangement and balancing switch configuration 326, the battery management microcontroller 327, the battery system interface 328, and the sensor 360 appear in the singular and only five multi-cell blocks 321-325 are shown in FIG. 3A, 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 balancing switch configurations, it should be understood that the components used in the arrangements and balancing switches described herein may be distributed among any suitable number of devices (e.g., switches).

[0072] FIG. 3B 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., 321A-321C) and may form a multi-cell block as described above. In addition, the representative cell set may include a cell multiplexing switch (e.g., 326A1), the cell balance switch and resistor (e.g., 326A2), a cell block microcontroller (e.g., 327A), a battery management microcontroller interface (e.g., 328A), a sensor (e.g., 360A), and an input / output bus (e.g., 321IO) 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.

[0073] In some embodiments, each cell (e.g., each of 321A-321C) 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., 321IO) and connect or isolate a given cell to a balance resistor (e.g., one of the resistors in 326A2) that shares the balance bus with other cells. Furthermore, in a discharge mode, one cell (e.g., 321A) may be connected to the input / output bus and isolated from the balance resistor. The remaining cells (e.g., 321B-321C) may be isolated from the input / output bus and connected to a corresponding balance resistor. Furthermore, in a charge mode according to some embodiments, all cells (e.g., 321A-321C) may be connected to the input / output bus and isolated from the balance resistor 326A2.

[0074] According to some embodiments, the cell block microcontroller (e.g., 327A) may generate switching waveforms to ensure that 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 communication from a battery management microcontroller (e.g., 327 in FIG. 3A) to which the cell block microcontroller may be connected via a battery management microcontroller interface.

[0075] 3C is an exemplary cross-sectional schematic diagram of an electrochemical system in which an anisotropic force is applied to an electrochemical cell (e.g., 321A), 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.

[0076] In FIG. 3C, the system can include an electrochemical cell 321A and, in some embodiments, a pressure distributor 334 that includes a fluid associated with the electrochemical cell 321A. The pressure distributor 334 can be configured to apply an anisotropic force to a component of the electrochemical cell 321A via the pressure distributor 334. For example, in the set of embodiments illustrated in FIG. 3C, the pressure transmitter 336 can be configured to apply an anisotropic force to the pressure distributor 334, which in turn applies an anisotropic force to at least one component (e.g., an electrode) of the electrochemical cell 321A. The system can also include a substrate 332 on which the electrochemical cell is disposed. The substrate 332 can include, for example, a table surface, a surface of a vessel in which the electrochemical cell 321A is housed, or any other suitable surface.

[0077] The pressure distributor 334 can be associated with the electrochemical cell 321A 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 can 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. Generally, 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. 3C, the pressure distributor 334 and the electrochemical cell 321A are in direct contact.

[0078] 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 can be found between the first and second articles that crosses only solid and / or liquid components. Such a path can be in the form of a substantially straight line in some embodiments. The pressure distributor can indirectly contact the electrochemical cell in some embodiments 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.

[0079] 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 334 may be positioned between an electrode and a container that at least partially surrounds the electrochemical cell. In some embodiments, the pressure distributor 334 may be positioned between a current collector and a container that at least partially surrounds the electrochemical cell. In some embodiments, the pressure distributor 334 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 334 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.

[0080] 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 334 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.

[0081] In some embodiments, the pressure distributor may be positioned 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 less than about 10 times, less than about 5 times, less than about 2 times, less than about 1 time, less than about 0.5 times, or less than about 0.25 times the maximum cross-sectional dimension of the electrode.

[0082] 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 can 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.

[0083] In some embodiments, force can be applied to electrochemical cell 321A or a component of electrochemical cell 321A (e.g., an electrode of the electrochemical cell) through pressure distributor 334. 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.

[0084] A force can be applied to the electrochemical cell or a part thereof via the pressure distributor in various ways. In some embodiments, applying a force to the pressure distributor includes applying a force to an outer surface of the pressure distributor. This can be accomplished, for example, via the pressure transmitter 336. For example, in FIG. 3C, the pressure transmitter 336 can be positioned to apply an anisotropic force to the electrochemical cell 321A via the pressure distributor 334 by applying a force to a surface 340 of the pressure distributor 334. 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 the force applied to and / or via the first component can 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 positioned between the pressure transmitter and the pressure distributor, but the force can 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 followed through the solid and / or liquid material from the pressure distributor to the electrochemical cell. Such a path may be substantially (e.g., completely) linear in some embodiments.

[0085] 3C, pressure transmitter 336 and electrochemical cell 321A are positioned on opposite sides of pressure distributor 334. Thus, when an anisotropic force (e.g., an anisotropic force in the direction of arrow 150) is applied to and / or by pressure transmitter 336 to surface 340, said force can be transmitted through pressure distributor 334 onto surface 342 of electrochemical cell 321A and to components of electrochemical cell 321A.

[0086] 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. 3C, a force can be applied to the electrochemical cell 321A through the pressure distributor 334 by transporting additional fluid through an inlet (not shown) of the pressure distributor 334 (e.g., by expanding the pressure distributor 334). 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. 3C, as additional fluid is applied to the pressure distributor 334, the pressure transmitter 336 can be configured to restrict movement of a boundary of the pressure distributor 334 such that a force is applied to the surface 342 of the electrochemical cell 321A.

[0087] In some embodiments, fluid can be applied to the pressure distributor 334 before the pressure distributor 334 is disposed between the electrochemical cell 321A and the pressure transmitter 336. After the fluid is applied, the pressure distributor 334 can be compressed and positioned between the electrochemical cell 321A and the pressure transmitter 336, and the compression of the fluid in the pressure distributor 334 can then cause a force to be applied to the surface 342 of the electrochemical cell 321A (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.

[0088] The fluid in pressure distributor 334 can cause pressure transmitted through pressure distributor 334 to be applied relatively evenly across surface 342 of electrochemical cell 321A (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 334 reduces and / or eliminates points of relatively high pressure on surface 342 as fluid in areas of relatively high pressure is transported to areas of relatively low pressure.

[0089] In some embodiments, the degree to which the pressure distributor evenly distributes the force applied to the electrochemical cell can 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. 3C, the outer surface 340 of the pressure transmitter 336 faces the outer surface 342 of the electrochemical cell 321A. 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. 3C, the outer surface 340 of the pressure transmitter 336 is substantially parallel to the outer surface 342 of the electrochemical cell 321A. 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.

[0090] The pressure distributor can 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.

[0091] 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.

[0092] In some embodiments, the pressure distributor can 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 can 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.

[0093] 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 certain 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.

[0094] A variety of fluids can be used in pressure distributors. 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.

[0095] 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 can 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.

[0096] The fluid used in connection with the pressure distributor can have any suitable viscosity. In some embodiments, a Newtonian fluid can be used in the pressure distributor, although some embodiments are not so limited and non-Newtonian fluids (e.g., shear thinning fluids, shear thickening fluids, etc.) can also be used. 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).

[0097] 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.

[0098] Also, the pressure transmitter 336 can adopt various configurations. In some embodiments, the pressure transmitter 336 is movable relative to the electrochemical cell 321A. In some such embodiments, a force can be applied to the electrochemical cell 321A via the pressure distributor 334 by bringing the pressure transmitter 336 closer to the electrochemical cell 321A and / or maintaining a separation between the electrochemical cell 321A and the pressure transmitter 336. As one particular example, in some embodiments, the pressure transmitter 336 includes a compression spring, a first applicator structure, and a second applicator structure. The first applicator structure can correspond, for example, to a flat plate of a rigid material, or any other suitable structure. The second applicator structure can 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 the surface 342 of the electrochemical cell 321A 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, to Scordilis-Kelley et al., entitled "Application of Force in Electrochemical Cells," filed Aug. 4, 2009, and incorporated herein by reference in its entirety for all purposes.

[0099] In some embodiments, the pressure transmitter 336 is substantially immovable relative to the electrochemical cell 321A, and a force can be applied to the electrochemical cell, for example, by pressurizing the pressure distributor 334. In some such embodiments, the substantially immovable pressure transmitter 336 limits the movement of one or more boundaries of the pressure distributor 334, thereby applying an anisotropic force to the electrochemical cell 321A, such that pressurizing the pressure distributor can result in the application of a force to the electrochemical cell.

[0100] 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 321A and the pressure distributor 334 are disposed. As one particular example, the pressure transmitter 336 may form a first wall of the package containing the electrochemical cell 321A, while the substrate 332 may form a second wall of the package (e.g., opposite the first wall). In some embodiments, the movement of the pressure transmitter 336 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 an amount of fluid in the pressure distributor 334.

[0101] 3C shows 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 321A 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 321A 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.

[0102] 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 321A. For example, the pressure distributor 334 may include an inlet and an outlet configured to transport fluid through the pressure distributor 334. As the fluid is transported through the pressure distributor 334, it can absorb heat from the electrochemical cell 321A and transport away from the system via the outlet. For example, a pump, a vacuum, or any other suitable device can be used to transport the fluid through the pressure distributor.

[0103] In some embodiments, the fluid used in connection with the pressure distributor can 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.).

[0104] The embodiments described herein can be used with a variety of electrochemical cells. While primary (disposable) and secondary (rechargeable) electrochemical cells can 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 application of uniform 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.

[0105] 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 3D. In Figure 3D, a general embodiment of an electrochemical cell 321A includes a cathode 310, an anode 312, and an electrolyte 314 in electrochemical communication with the cathode and anode.

[0106] In some embodiments, the electrochemical cell 321A can be optionally at least partially enclosed by a containment structure 316. The containment structure 316 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 321A by disposing the pressure distributor outside the containment structure 316 in direct or indirect contact with the surface 318A and / or the surface 318B. When positioned in this manner, the pressure distributor can be configured to apply a force directly or indirectly to the surface 318A and / or the surface 318B of the containment structure 316, as described above. In some embodiments, the pressure distributor can be positioned between the cathode 310 and the containment structure 316, or between the anode 312 and the containment structure 316. 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.

[0107] A typical electrochemical cell system would, 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 configuration shown in the drawings and described herein.

[0108] The components of the electrochemical cell 321A may be assembled in some cases such that the electrolyte is disposed between the cathode and the anode in a planar configuration. For example, in the embodiment shown in FIG. 3D, the cathode 310 of the electrochemical cell 321A 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 321A (although not shown in FIG. 3D) or may be removed from the cathode 310 prior to assembly of the electrochemical cell. Additionally, in FIG. 3D, the anode 312 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 314 is also illustrated as being substantially planar in FIG. 3D.

[0109] In some embodiments, the electrochemical cell 321A can 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 321A can 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.

[0110] Although Figure 3D shows the electrochemical cells arranged in a planar configuration, it should be understood that the principles of some embodiments may be employed to construct any electrochemical cell arrangement in any configuration. In addition to the shape illustrated in Figure 3D, 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, to Affinito et al., entitled "Electrode Protection in both Aqueous and Non-Aqueous Electrochemical Cells, including Rechargeable Lithium Batteries," filed April 06, 2006, which is incorporated herein by reference in its entirety.

[0111] 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. 3D, the cathode 310 includes a cathode active surface 320 and the anode 312 includes an anode active surface 322.

[0112] In some embodiments, the anisotropic force applied to the pressure transmitter 336 and / or via the pressure distributor 334 (and ultimately to the surface 342 of the electrochemical cell 321A 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 334 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 3C and 3D, an anisotropic force in the direction of arrow 370 may be applied to the electrochemical cell 321A via the pressure distributor 334. The anisotropic force applied in the direction of arrow 370 includes a component 372 that is perpendicular to the anode active surface 322 and perpendicular to the cathode active surface 320. Additionally, an anisotropic force applied in the direction of arrow 370 will include a component 374 that is not perpendicular (and is actually parallel) to the anode active surface 322 and the cathode active surface 320 .

[0113] 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.

[0114] 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.

[0115] 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.

[0116] The electrode active surface and anisotropic force can 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 can readily select anode materials, alloys, mixtures, etc. with known or predictable properties, or can readily test the hardness or softness of such surfaces, and can readily select cell construction techniques and configurations to provide appropriate forces to achieve what is described herein. Simple tests can be performed, for example, by placing a series of active materials, each subjecting them 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 without cell cycling (for prediction of the selected combination during cell cycling) or with cell cycling with selection and observation of the associated results.

[0117] 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 can be defined as, 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 approx. 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 can 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.

[0118] 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 can 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 can 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 can include a cathode, and a component of the anisotropic force perpendicular to the cathode active surface can 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).

[0119] In some cases, the anisotropic force can 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 can 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.).

[0120] 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.

[0121] 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.

[0122] One skilled in the art can 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 can generate a plot of pressure across a surface portion, for example, by using a Tekscan I-Scan system to measure the pressure field.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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 by reference in its entirety for all purposes.

[0132] 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.

[0133] 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.

[0134] U.S. patent application Ser. No. 16 / 527,903, entitled "Multiplexed Charge Discharge Battery management System," and filed July 31, 2019, is hereby incorporated by reference in its entirety for all purposes.

[0135] The following documents are incorporated herein by reference in their entirety for all purposes: U.S. Patent No. 7,247,408, filed May 23, 2001, entitled "Lithium Anodes for Electrochemical Cells"; U.S. Patent No. 5,648,187, filed March 19, 1996, entitled "Stabilized Anode for Lithium-Polymer Batteries"; U.S. Patent No. 5,961,672, filed July 7, 1997, entitled "Stabilized Anode for Lithium-Polymer Batteries"; U.S. Patent No. 5,919,587, filed May 21, 1997, entitled "Novel Composite Cathodes, Electrochemical Cells Comprising Novel Composite Cathodes, and Processes for Fabricating Same"; U.S. Patent Application No. 11 / 400,781, filed April 6, 2006, published as U.S. Patent Application Publication No. 2007 / 0221265, entitled "Rechargeable Lithium / Water, Lithium / Air Batteries"; International Application No. PCT / US2008 / 009158, filed July 29, 2008, published as WO 2009 / 017726, entitled "Swelling Inhibition in Lithium Batteries"; U.S. Patent Application Serial No. 12 / 312,764, filed May 26, 2009, published as U.S. Patent Application Publication No. 2010 / 0129699, entitled "Separation of Electrolytes"; International Application No. PCT / US2008 / 012042, filed October 23, 2008, published as WO 2009 / 054987, entitled "Primer for Battery Electrode"; U.S. Patent Application Serial No. 12 / 069,335, filed February 8, 2008, published as U.S. Patent Application Publication No. 2009 / 0200986, entitled "Protective Circuit for Energy-Storage Device"; U.S. Patent Application Serial No. 11 / 400,025, filed April 6, 2006, published as U.S. Patent Application Publication No. 2007 / 0224502, entitled "Electrode Protection in both Aqueous and Non-Aqueous Electrochemical Cells, including Rechargeable Lithium Batteries"; U.S. patent application Ser. No. 11 / 821,576, filed Jun. 22, 2007, published as U.S. Patent Application Publication No. 2008 / 0318128, entitled "Lithium Alloy / Sulfur Batteries"; U.S. patent application Ser. No. 11 / 111,262, filed Apr. 20, 2005, published as U.S. Patent Application Publication No. 2006 / 0238203, entitled "Lithium Sulfur Rechargeable Battery Fuel Gauge Systems and Methods"; U.S. patent application Ser. No. 11 / 728,197, filed Mar. 23, 2007, published as U.S. Patent Application Publication No. 2008 / 0187663, entitled “Co-Flash Evaporation of Polymerizable Monomers and Non-Polymerizable Carrier Solvent / Salt Mixtures / Solutions”; International Application No. PCT / US2008 / 010894, filed September 19, 2008, published as WO 2009 / 042071, entitled "Electrolyte Additives for Lithium Batteries and Related Methods"; International Application No. PCT / US2009 / 000090, filed January 8, 2009, published as WO 2009 / 089018, entitled "Porous Electrodes and Associated Methods"; U.S. Patent Application No. 12 / 535,328, filed Aug. 4, 2009, published as U.S. Patent Application Publication No. 2010 / 0035128, entitled “Application of Force In Electrochemical Cells”; U.S. patent application Ser. No. 12 / 727,862, filed Mar. 19, 2010, entitled "Cathode for Lithium Battery"; U.S. patent application Ser. No. 12 / 471,095, filed May 22, 2009, entitled "Hermetic Sample Holder and Method for Performing Microanalysis Under Controlled Atmosphere Environment"; (claiming priority from Provisional Patent Application No. 61 / 236,322, filed Aug. 24, 2009, entitled "Release System for Electrochemical Cells") U.S. Patent Application No. 12 / 862,513, filed Aug. 24, 2010, entitled "Release System for Electrochemical Cells"; U.S. Provisional Patent Application No. 61 / 376,554, filed Aug. 24, 2010, entitled "Electrically Non-Conductive Materials for Electrochemical Cells"; U.S. Patent Application No. 12 / 862,528, filed Aug. 24, 2010, published as U.S. Patent Application Publication No. 2011 / 0177398, entitled "Electrochemical Cell"; U.S. Patent Application No. 12 / 862,563, filed Aug. 24, 2010, published as U.S. Patent Application Publication No. 2011 / 0070494, entitled “Electrochemical Cells Comprising Porous Structures Comprising Sulfur” [Attorney Docket No. S1583.70029US00]; U.S. Patent Application No. 12 / 862,551, filed Aug. 24, 2010, published as U.S. Patent Application Publication No. 2011 / 0070491, entitled “Electrochemical Cells Comprising Porous Structures Comprising Sulfur” [Attorney Docket No. S1583.70030US00]; U.S. Patent Application No. 12 / 862,576, filed Aug. 24, 2010, published as U.S. Patent Application Publication No. 2011 / 0059361, entitled “Electrochemical Cells Comprising Porous Structures Comprising Sulfur” [Attorney Docket No. S1583.70031US00]; U.S. Patent Application No. 12 / 862,581, filed Aug. 24, 2010, published as U.S. Patent Application Publication No. 2011 / 0076560, entitled “Electrochemical Cells Comprising Porous Structures Comprising Sulfur” [Attorney Docket No. S1583.70024US01]; U.S. Patent Application No. 61 / 385,343, filed Sep. 22, 2010, entitled "Low Electrolyte Electrochemical Cells" [Attorney Docket No. S1583.70033US00]; and No. 13 / 033,419, entitled "Porous Structures for Energy Storage Devices," filed Feb. 23, 2011 [S1583.70034US00]. All other patents and patent applications disclosed herein are also incorporated by reference in their entirety for all purposes.

[0136] 4A shows an exemplary high-level process 400A for controlling the charge rate or charge current of the cell. Improvements to the exemplary process 400A are described in detail in the following paragraphs.

[0137] In some embodiments, the exemplary process 400A may include an act 430A, in which an electrochemical cell (such as electrochemical cell 121A described above) may be controlled to be charged, for at least a portion of a charge cycle, 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, as described herein.

[0138] In some embodiments, the process 400A may then be terminated or repeated as necessary, such as for more charge / discharge cycles.

[0139] 4B shows an exemplary process 400B for controlling the charge rate or charge current of a cell (such as electrochemical cell 121A described above). Improvements to the exemplary process 400B are described in detail in the following paragraphs.

[0140] In some embodiments, the exemplary process 400B may include an improvement 410 in which characteristics of the cells may be monitored (e.g., by a controller such as 114 and a sensor 116 as described above) as described herein.

[0141] In some embodiments, the exemplary process 400B may then optionally proceed to refinement 420 and review to determine if at least one threshold has been met, as described herein. For example, the threshold may be a threshold amount (or rate or current) of discharge in the discharge history, a pressure measurement on the cell, or the like.

[0142] In some embodiments, if a threshold is met, the representative process 400B then proceeds to refinement 430A, where the cell may be controlled (e.g., by controller 114) to be charged at a charge rate or charge current that is lower than the discharge rate or discharge current for a portion of the cell's discharge cycle. For example, if the cell has had a discharge cycle or history of discharging at 300 mA, the cell may be controlled to be charged at 150 mA or less, as described herein. Alternatively, if a threshold is not met, monitoring of the characteristics may continue.

[0143] In some embodiments, the exemplary process 400B may then optionally proceed to refinement 431B, where induced discharge of the cell may be triggered by the controller. The induced discharge may be triggered at various times and for various reasons, as described herein.

[0144] In some embodiments, exemplary process 400B may then optionally proceed to either improvement 432 or 434. For example, if process 400B proceeds from improvement 431B to improvement 432, the cell may be controlled to charge at a charge rate at least two times lower than its discharge rate, as described herein.

[0145] Alternatively or additionally, process 400B may proceed from improvement 431B to improvement 434, in which case the cell may be controlled to charge at a charge rate four times lower than its discharge rate, as described herein.

[0146] In some embodiments, the process 400B may then be terminated or repeated as necessary, such as for more charge / discharge cycles.

[0147] It should be understood that either improvement 432 and / or 434, although depicted as separate improvements in FIG. 4B, may actually be integral with improvement 430A.

[0148] 4C illustrates an exemplary high-level process 400C for inducing discharge of the cell. Improvements to the exemplary process 400C are described in detail in the following paragraphs.

[0149] In some embodiments, the exemplary process 400C may include an improvement 430C in which induced discharge of an electrochemical cell (such as electrochemical cell 121A described above) may be effected before and / or after the charging step, as described herein.

[0150] In some embodiments, the process 400C may then be terminated or repeated as necessary, such as for more charge / discharge cycles.

[0151] 4D illustrates an exemplary process 400D for inducing discharge of a cell. Improvements to the exemplary process 400D are described in detail in the following paragraphs.

[0152] In some embodiments, the exemplary process 400D may optionally include a refinement 410 in which characteristics of the cells may be monitored as described herein.

[0153] In some embodiments, the exemplary process 400D may then optionally proceed to refinement 420, which may be considered to determine whether at least one threshold has been met. For example, a threshold may be a threshold amount (or rate or current) of discharge in a discharge history, a pressure measurement on the cell, a thickness or size of the cell, or a threshold measurement of a monitored characteristic.

[0154] In some embodiments, if the threshold is met, the exemplary process 400D may then proceed to remediation 430C, where induced discharge of the cell may be triggered by a controller (e.g., by controller 114) as described herein. For example, as described herein, the threshold may be met if the charge / discharge history of the cell indicates that a discharge cycle has ended, that a discharge cycle and / or discharge step is still in progress, that a charge cycle has ended, or that a charge cycle and / or charge step is about to begin. Alternatively, if the threshold is not met, the characteristic may continue to be monitored.

[0155] In some embodiments, exemplary process 400D may then optionally proceed to refinement 431D, where, for at least a portion of a charge cycle, the cell is controlled to be 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, as described herein.

[0156] In some embodiments, exemplary process 400D may then optionally proceed to either improvement 432 or 434. For example, if process 400D proceeds from improvement 431D to improvement 432, the cell may be controlled to charge at a charge rate at least two times lower than its discharge rate.

[0157] Alternatively or additionally, process 400D may proceed from improvement 431D to improvement 434, where the cell may be controlled to charge at a charge rate that is four times lower than its discharge rate.

[0158] In some embodiments, the process 400D may then be terminated or repeated as necessary, such as for more charge / discharge cycles.

[0159] It should be understood that either improvement 432 and / or 434, although depicted as separate improvements in FIG. 4D, may actually be integral with improvement 430C.

[0160] 5A shows an exemplary process 500A for monitoring cell characteristics, inducing discharge, or controlling the charge rate or charge current of the cell. Improvements to the exemplary process 500A are described in detail in the following paragraphs.

[0161] In some embodiments, the exemplary process 500A may include an improvement 510 in which characteristics of the cells may be monitored (e.g., by a controller such as 114 and a sensor 116 as described above) as described herein.

[0162] In some embodiments, process 500A then proceeds from improvement 510 to improvement 530, where based on the monitoring in improvement 510, the controller may trigger induced discharging of the cells and / or controlled charging of the cells as described herein.

[0163] In some embodiments, the process 500A may then terminate or be repeated as necessary.

[0164] 5B shows an exemplary process 500B for monitoring cell characteristics and inducing discharge or controlling the charge rate or charge current of the cell. Improvements to the exemplary process 500B are described in detail in the following paragraphs.

[0165] In some embodiments, the exemplary process 500B may include an improvement 510 in which characteristics of the cells may be monitored (eg, by a controller such as 114 and a sensor 116 as described above).

[0166] In some embodiments, the exemplary process 500B may then optionally proceed to refinement 520, as described herein, to determine if at least one threshold has been met. For example, a threshold may be a threshold measurement of a monitored characteristic, such as a threshold amount (or rate or current) of discharge in a discharge history, a pressure measurement on the cell, a thickness or size of the cell, etc.

[0167] In some embodiments, if the threshold is met, the exemplary process 500B then proceeds to remediation 530, where induced discharge of the cell may be triggered by a controller (e.g., by controller 114) as described herein. For example, as described herein, the threshold may be met if the charge / discharge history of the cell indicates that a discharge cycle has ended, that a discharge cycle and / or discharge step is still in progress, that a charge cycle has ended, or that a charge cycle and / or charge step is about to begin. Alternatively, if the threshold is not met, monitoring of the characteristics may continue.

[0168] In some embodiments, exemplary process 500B can then optionally proceed to either improvement 532 or 534. For example, if process 500B proceeds from improvement 530 to improvement 532, the battery may be controlled to charge at a charge rate that is at least two times lower than its discharge rate.

[0169] Alternatively or additionally, if process 500B proceeds from improvement 530 to improvement 534, the cell may be controlled to charge at a charge rate that is four times lower than its discharge rate.

[0170] In some embodiments, process 500B may then terminate or repeat as necessary.

[0171] It should be understood that either improvement 532 and / or 534, although depicted as separate improvements in FIG. 5B, may actually be integral with improvement 530.

[0172] The inventors recognize and appreciate that the several embodiments described above, when implemented, may produce results that represent various improvements over the prior art. EXAMPLES

[0173] In the following Examples 1 to 5 and Tables 1 to 4, the cells were subjected to a load of 10 to 12 kg / cm 2 The material is cycle tested under a pressure of 1000 psi.

[0174] Example 1: Example 1 shows that cycle life is poor when cells are cycled at the same charge and discharge rates (current or time) over a wide range of rates. Cells with NCM111 cathodes, 15 μm evaporated lithium anodes, and electrolytes were charged at 10 kg / cm 2 The cell was cycled under a pressure of 1000 psi. The electrolyte was a 1 molar solution of lithium hexafluorophosphate in a 2:1 weight ratio of ethylene carbonate and dimethyl carbonate. The total area of ​​the active electrodes in the cell was 99.4 cm. 2 The cell capacity was 200 mAh. The cells were charged to 4.35 V and discharged to 3.2 V at the currents in Table 1 below. The charge and discharge currents were the same. In the range of charge and discharge currents from 40 to 200 mA (a 5-fold difference in current), all cells showed short cycle lives of 38 to 56 cycles. [Table 1]

[0175] Example 2: Example 2 shows that the cycle life is improved when the charge current is significantly reduced while the discharge current is constant. The higher the discharge current / charge current ratio, the longer the cycle life.

[0176] A similar cell to that in Example 1 was used, but with an NCM622 cathode. The cell capacity was 330 mAh. The cell was charged to 4.35 V and discharged to 3.2 V at the currents in Table 2 below. [Table 2]

[0177] The cycle life in Table 2 was longer as the discharge current / charge current ratio increased. The greatest effect was observed when the ratio was between 3 and 6, and the effect decreased further for higher ratios and longer charging times.

[0178] Example 3: Example 3 shows that the cycle life is improved when the charge current is fixed and the discharge current is fairly high. The higher the discharge current / charge current ratio, the longer the cycle life.

[0179] The cell was similar to Example 2, except that the electrolyte was LiIon 1401. The cell capacity was 330 mAh. The cell was charged to 4.35 V and discharged to 3.2 V at the currents in Table 3 below. [Table 3]

[0180] By changing the discharge current / charge current ratio from 1 to 4 while maintaining a constant charge current, the cycle life was dramatically improved by six times.

[0181] Example 4: Example 4 shows that when the charge current was fixed and the discharge current was fairly high, the cycle life was improved, but not necessarily continuously. The cells were discharged under conditions where the discharge was periodically interrupted and restarted for a period of time.

[0182] The cell was the same as in Example 3. The cell capacity was 330 mAh. The cell was charged to 4.35 V and discharged to 3.2 V at the currents in Table 3 below. Charge and discharge currents of 100 mA were maintained.

[0183] The discharge process at 400mA was not continuous. Discharge at 400mA continued for 10 seconds, then was interrupted for 30 seconds and resumed. This process was cyclic. The cycle life data obtained for the two processes are shown in Table 4. [Table 4]

[0184] Example 5: Example 5 shows that cycle life is improved only when high discharge current / charge current ratio is applied for a significant portion of the discharge time or discharge capacity. When high current discharge condition is only a small portion of the total discharge time, the improvement in cycle life is not significant.

[0185] The cell was the same as in Example 4, except that an NCM721 cathode was used. The cell capacity was 360 mAh. The cell was charged to 4.4 V and discharged to 3.2 V.

[0186] The first portion of the cells experienced equal charge and discharge currents of 100 mA and achieved a cycle life of 43 cycles with a cutoff of 250 mAh.

[0187] A second portion of the cells was charged at a constant current of 100 mA, charged to 95% of capacity at 100 mA, and then discharged in two steps at 400 mA to obtain the remaining 5% of capacity.

[0188] The cycle life of these cells was 52 cycles, a gain of 9 cycles or 21% or less than that obtained when a high discharge current / charge current ratio of 4 was applied to 5% of the total discharge capacity. The inventors recognized and appreciated that a better cycle life can be expected when the 5% of the discharge capacity obtained at a higher discharge current / charge current ratio, e.g., the average discharge rate or average discharge current during the previous discharge cycle is 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 discharge of at least 5% of the discharge capacity of said cell during the previous discharge cycle is at least two times higher, or four times higher, than the average charge rate or average charge current during the charge cycle.

[0189] 6A shows an exemplary high-level process 600A for discharging a set of cells of a battery. Improvements to the exemplary process 600A are described in detail in the following paragraphs.

[0190] In some embodiments, the exemplary process 600A may include an improvement 630A in which a set of cells of a battery may be selectively discharged based on at least one criterion using a multiplexing switch device (e.g., multiplexing switch device 112 described above). Further, the multiplexing switch device may be connected to two or more sets (e.g., 121, 122, 123, and / or 124) (e.g., 121A-121C) of cells of at least one battery (e.g., 120-150). Each set of cells may comprise one or more cells.

[0191] In some embodiments, the process 600A may then terminate or repeat as necessary.

[0192] 6B shows an exemplary high-level process 600B for discharging a set of cells of a battery. Improvements to the exemplary process 600B are described in detail in the following paragraphs.

[0193] In some embodiments, the exemplary process 600B may optionally begin at refinement 610 where a multiplexing switch device may be used to connect the set of cells to a load in a topology adopted by the load. A battery (e.g., 120-150) may include sets (e.g., 121, 122, 123, and / or 124) of the cells (e.g., 121A-121C), each set of cells may comprise one or more cells. For example, a multiplexing switch device may connect the cells to a load in series, parallel, series / parallel, or any other suitable topology necessary to meet the voltage and current requirements of the load or the desires of a given application or user.

[0194] In some embodiments, the exemplary process 600B may then optionally proceed to refinement 620, where at least one criterion, and / or some parameters of the criterion, may be measured or otherwise monitored in association with a battery or cells of a battery that may have already discharged or are discharging at least one set of cells, to determine whether the criterion has been met.

[0195] For example, a sensor (e.g., 116 in FIG. 1A and FIG. 1F) may measure the delivered discharge capacity at the connection between the load and the set of cells currently connected to the load, or may measure the current of the set of cells. Alternatively or additionally, the sensor may measure any of the following: duration of connection (which may be at least 0.01 seconds in some embodiments), capacity accumulated over some connection between the load and the set of cells, voltage of the set of cells and / or at least one other set of cells, end of 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 fade rate of the set of cells during connection, temperature of the set of cells, and pressure of the set of cells.

[0196] In some embodiments, the criteria may include the order in which the cells or set of cells are discharged. Alternatively or additionally, the criteria may be the value of a function having any of the above as parameters. According to some embodiments, the criteria does not include the number of previous discharge cycles of the set of cells.

[0197] In some embodiments, if the criteria are met, the representative process 600B may then proceed to refinement 630, where a multiplexing switch device (such as the multiplexing switch device 112 described above) may be used to selectively discharge the next set of cells in the battery based on the criteria. For example, if the currently discharged set of cells meets any required criteria or criteria, the set of cells may be disconnected and the next set of cells may be connected as described herein (where the next set may be determined by criteria or criteria that may be the same or different as those described above). Alternatively, if the criteria are not met, monitoring may continue. According to some embodiments, the connection between the single cell and the load may be at least 0.01 seconds in duration. The inventors have recognized and understood that a connection duration shorter than 0.01 seconds may surprisingly generate more noise than the 0.01 second case and may not achieve negligible electrochemistry of the cells.

[0198] In some embodiments, the exemplary process 600B may then optionally proceed to refinement 631, where a multiplexing switch device may be used to isolate a single set of the cells for discharging while other sets of the cells are not discharging. For example, when a controller (e.g., 114 in FIGS. 1A and 1F) determines that the cell 121B should be discharged, it may cause a multiplexing switch device to be used to isolate the cell 121B for discharging while the cells 121A and 121C are not discharging.

[0199] In some embodiments, exemplary process 600B may then optionally proceed to any of improvements 632, 634, 636, and / or 638. For example, if process 600B proceeds from improvement 631 to improvement 632, a multiplexing switch device may be used to selectively discharge the 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.

[0200] Alternatively or additionally, process 600B may proceed from improvement 631 to improvement 634, where a multiplexing switch device may be used to selectively discharge the set of cells at a first rate that is at least four times higher than a second rate at which the set of cells is charged.

[0201] Alternatively or additionally, process 600B may proceed from improvement 631 to improvement 636, where the discharging of the sets of cells may be overlapped in time, for example by using a multiplexing switch device as described above.

[0202] Alternatively or additionally, process 600B may proceed from improvement 631 to improvement 638, where power may continue to be supplied from the set of cells during switching between different sets.

[0203] It should be understood that any of improvements 631, 632, 634, 636, and / or 638, although depicted as separate improvements in FIG. 6B, may actually be integral with improvement 630.

[0204] In some embodiments, the exemplary process 600B may then proceed to an optional refinement 640, where a multiplexing switch device may be used to charge the set of cells in parallel, as previously described.

[0205] According to some embodiments, any number of the sets of cells may be discharged simultaneously, including all the sets of the cells in a battery, battery pack, or system. For example, in a battery having four cells, all four cells (or only two or three) may be discharged simultaneously, resulting in whatever discharge current is desirable for the load or application and possible for the cells. Furthermore, in some embodiments, the number of cells or sets to be discharged or charged is selected based on at least one criterion, such as a discharge current for discharging. In some embodiments, the order in which the number of cells or sets of cells are discharged or charged is selected based on at least one criterion, such as a discharge current for discharging. In some embodiments, both the number of cells or sets to be discharged or charged and the order in which they are discharged or charged are selected based on at least one criterion, such as a discharge current for discharging.

[0206] In some embodiments, process 600B may then terminate or repeat as necessary. For example, process 600B may be repeated through any suitable number of cycles. According to some embodiments, for each cycle or some cycles, each cell may be discharged once before any cell is discharged twice.

[0207] 6C shows an exemplary high-level process 600C for controlling a battery pack. Improvements to the exemplary process 600C are described in detail in the following paragraphs.

[0208] In some embodiments, the exemplary process 600C may include a refinement 630C in which switches may be controlled (e.g., by a controller such as 114 described above) to sequentially discharge sets (e.g., 121, 122, 123, and / or 124) of cells (e.g., 121A-121C) in a battery pack (e.g., 210) using an integrated switching control system. Additionally, a multiplexing switch device may be connected to two or more sets of cells of the battery. Each set of cells may include one or more cells.

[0209] In some embodiments, the process 600C may then terminate or repeat as necessary.

[0210] 6D shows an exemplary high-level process 600D for controlling a battery pack. Improvements to the exemplary process 600D are described in detail in the following paragraphs.

[0211] In some embodiments, the exemplary process 600D may include a refinement 630D in which a switch may be controlled (e.g., by a controller such as 114 described above) to discharge a set (e.g., 121, 122, 123, and / or 124) of cells (e.g., 121A-121C) in a battery pack (e.g., 210) based on a criterion using an embedded switching control system. Further, a multiplexing switch device may be connected to two or more sets of cells of the battery. Each set of cells may comprise one or more cells. In some embodiments, the criterion may include any of the duration of a connection between the load and the set of cells currently connected to the load, the delivered discharge capacity in the connection, and the value of a function having one or more parameters.

[0212] In some embodiments, the process 600D may then terminate or repeat as necessary.

[0213] The inventors recognize and appreciate that the several embodiments described above, when implemented, may provide results that represent various improvements over the prior art. For example, in one embodiment, a 99.41 cm active electrode area was produced from a NCMA622 cathode (BASF) with 50 μm Li foil and a 25 μm Celgard 2325 separator filled with F9 (BASF) electrolyte containing 1 wt% lithium bis(oxalato)borate (LiBOB). 2The cells were fabricated having a capacity of 12 kg / cm. The cells were assembled into 13 batteries containing 4 cells each. The batteries were subjected to 13 charge-discharge cycle tests using several embodiments under the conditions shown in Tables 5 and 6 below. The cells in the batteries were subjected to a load of 12 kg / cm during the cycle test. 2 The pressure was kept at 1000 psi and the temperature at 18° C. [Table 5] [Table 6]

[0214] Table 5 (Test Nos. 1-3) shows comparative examples (conducted by conventional technology), and summarizes the test results when the cells were connected in parallel, the charge / discharge current was evenly applied to the four cells, and the battery was charged / discharged at a constant current. The charge cutoff voltage was 4.35V, and the discharge cutoff voltage was 3.2V. The charge / discharge cycle was stopped when the battery capacity reached 800mAh.

[0215] Table 6 (Tests Nos. 4-13) summarizes the results of tests in which the cells were connected in parallel, the charge and discharge currents were applied equally to the four cells, and the batteries were charged at a constant current to 4.35V. The batteries were discharged such that the entire battery was at a constant discharge current. However, the individual cells were sequentially connected and disconnected from the load, and only one of the four cells was supplied with a discharge current pulse at a time. When this pulse was completed, the next cell was connected and the previous cell was disconnected. The cells were sequentially supplied with a discharge pulse (e.g., cell Nos. 1, 2, 3, 4, 1, 2, 3, 4, etc.) for a certain pulse time or until the discharge voltage reached 3.2V. Tests Nos. 4, 8, and 12 were full cell discharged with a single pulse. The other tests were partial cell discharged with single pulses of 0.1, 1, and 10 second duration. The charge and discharge cycles were stopped when the battery capacity reached 800mAh.

[0216] Figure 7A corresponds to test number 13 and shows the cell voltage profile at the beginning of a 10 second pulse discharge for the first 240 seconds, and Figure 7B shows the full discharge profile down to a voltage of 3.2 V. In Figure 7A, the cell number is shown as subjected to a repeating sequence of 10 second 300 mA pulses for the first 80 seconds.

[0217] Referring again to Tables 5 and 6, the inventors have recognized and understood that sequential application of the entire battery discharge current to a portion of the battery cells (Table 6) results in a surprising improvement in cycle life compared to uniform current distribution among all battery cells (Table 5) as has been done in the prior art. This improvement in cycle life can be up to six times, and the inventors have recognized that it can be a function of discharge pulse duration as well as charge / discharge rate. FIG. 7C, which shows battery cycle life as a function of pulse duration at two charge / discharge rates (corresponding to Test Nos. 4-11), indicates that cycle life can be particularly improved for pulse times longer than 0.1 seconds and pulse durations around 10 seconds. The inventors have recognized and understood that the improvement in battery cycle life described herein is possible even when using some embodiments during partial discharge, as shown in FIG. 7C, and as was not expected based on prior art experience. Furthermore, the full capacity of all cells, even if not uniform, can be utilized in some embodiments.

[0218] It should be understood that in some embodiments, the methods described above with reference to Figures 4A-6 may be varied in any of a number of ways. For example, in some embodiments, the steps of the methods described above may be performed in an order different from that described, the methods may include additional steps not described above, and / or the methods may not include all of the steps described above.

[0219] It should further be appreciated from the foregoing that some aspects may be implemented using a computing device. Figure 8 illustrates a general-purpose computing device in system 800 in the form of a computer 810, which may be used to implement some aspects, such as any of the controllers (e.g., 114) discussed above.

[0220] In the computer 810, components include, but are not limited to, a processing unit 820, a system memory 830, and a system bus 821 that couples various system components including the system memory to the processing unit 820. The system bus 821 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus, also known as Mezzanine bus.

[0221] The computer 810 typically includes a variety of computer readable media. Computer readable media may be any available media accessible by the computer 810, including both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and computer communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium or media that can be used to store the desired information and that can be accessed by the computer 810. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal, such as a carrier wave or other transport mechanism, and includes any information delivery media. The term "modulated data signal" means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared, etc. Combinations of any of the above are also intended to be included within the scope of computer-readable media.

[0222] The system memory 830 includes computer storage media in the form of volatile and / or nonvolatile memory such as read-only memory (ROM) 831 and random access memory (RAM) 832. A basic input / output system 833 (BIOS), containing the basic routines that help to transfer information between elements within the computer 810, such as during start-up, is typically stored in ROM 831. RAM 832 typically contains data and / or program modules that are immediately accessible to and / or presently being operated on by the processing unit 820. By way of example, and not limitation, FIG. 8 illustrates operating system 834, application programs 835, other program modules 839, and program data 837.

[0223] The computer 810 may also include other removable / non-removable, volatile / non-volatile computer storage media. By way of example only, FIG. 8 illustrates a hard disk drive 841 that reads from or writes to a non-removable, non-volatile magnetic medium, a magnetic disk drive 851 that reads from or writes to a removable, non-volatile magnetic disk 852, and an optical disk drive 855 that reads from or writes to a removable, non-volatile optical disk 859, such as a CD-ROM or other optical media. Other removable / non-removable, volatile / non-volatile computer storage media that may be used in the exemplary computing system include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 841 is typically connected to the system bus 821 by a non-removable memory interface, such as interface 840, and the magnetic disk drive 851 and optical disk drive 855 are typically connected to the system bus 821 by a removable memory interface, such as interface 850.

[0224] The drives and their associated computer storage media discussed above and illustrated in FIG. 8 store computer readable instructions, data structures, program modules, and other data for computer 810. In FIG. 8, for example, hard disk drive 841 is illustrated as storing operating system 844, application programs 845, other program modules 849, and program data 847. Note that these components may be the same as or different from operating system 834, application programs 835, other program modules 849, and program data 837. Operating system 844, application programs 845, other program modules 849, and program data 847 are given different numbers here to illustrate that, at a minimum, they are different copies. A user may enter commands and information into computer 810 through input devices such as a keyboard 892 and pointing device 891, commonly referred to as a mouse, trackball, or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite receiver, scanner, or the like. These and other input devices are often connected to the processing unit 820 through a user input interface 590 coupled to the system bus, but may also be connected by other interfaces and bus structures such as a parallel port, game port, or universal serial bus (USB). A monitor 891 or other type of display device is also connected to the system bus 821 through an interface, such as a video interface 890. In addition to the monitor, computers may also include other peripheral output devices such as speakers 897 and printer 899, which may be connected through an output peripheral interface 895.

[0225] The computer 810 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 880. The remote computer 880 may be a personal computer, a server, a router, a network PC, a peer device, or other common network node, and will typically include many or all of the elements described above relative to the computer 810, although only a memory storage device 881 is illustrated in FIG. 8. The logical connections depicted in FIG. 8 include a local area network (LAN) 871 and a wide area network (WAN) 873, but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets, the Internet, and the like.

[0226] When used in a LAN networking environment, the computer 810 is connected to the LAN 871 through a network interface or adapter 870. When used in a WAN networking environment, the computer 810 typically includes a modem 872 or other means for establishing communications over the WAN 873, such as the Internet. The modem 872, which may be internal or external, may be connected to the system bus 821 via a user input interface 890, or other suitable mechanism. In a networked environment, program modules depicted relative to the computer 810, or portions thereof, may be stored in a remote memory storage device. By way of example, and not limitation, FIG. 8 illustrates remote application programs 885 as residing on memory device 881. It is understood that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.

[0227] The embodiments may be embodied as a computer-readable storage medium (or a plurality of computer-readable media) (e.g., a computer memory, one or more floppy disks, compact disks (CDs), optical disks, digital video disks (DVDs), magnetic tapes, flash memories, circuitry in a Field Programmable Gate Array or other semiconductor device, or other tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods for implementing the various embodiments described above. As is evident from the foregoing examples, a computer-readable storage medium may retain information for a sufficient period of time to provide computer-executable instructions in a non-transitory form. Such a computer-readable storage medium may be transportable such that the programs stored thereon may be loaded (or read) into one or more different computers or other processors to implement the various aspects of the invention described above. As used herein, the term "computer-readable storage medium" encompasses only a tangible machine, mechanism, or device from which a computer can read information. Alternatively or additionally, some embodiments may be embodied as a computer readable medium other than a computer readable storage medium, examples of which include ephemeral media such as a propagating signal.

[0228] While several embodiments of the invention have been described and illustrated herein, those skilled in the art will readily envision various other means and / or structures for performing the functions and / or results and / or obtaining one or more of the advantages set forth above, and each such variation and / or improvement is deemed to be within the scope of the present invention. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary, and that the actual parameters, dimensions, materials, and / or configurations will depend on the particular application for which the teachings of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to some of the embodiments of the invention described herein. Thus, the foregoing embodiments are presented by way of example only, and it should be understood that within the scope of the appended claims and equivalents thereof, the invention may be practiced otherwise than as specifically described and claimed. The present invention relates to each individual feature, system, article, material, kit, and / or method described herein. Also, combinations of two or more such features, systems, articles, materials, kits, and / or methods are encompassed within the scope of the invention, if such features, systems, articles, materials, kits, and / or methods are not mutually inconsistent.

[0229] As used in the specification and the claims, the indefinite articles "a" and "an" should be understood to mean "at least one," unless expressly indicated otherwise.

[0230] As used in the specification and claims, the phrase "and / or" should be understood to mean "either or both" of conjugated elements, i.e., elements that are present conjunctively in some cases and disjointly in others. Unless expressly indicated, other elements may optionally be present other than the elements specifically identified by the "and / or" clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "A and / or B," when used in conjunction with an open-ended term such as "comprising," means, in one embodiment, A without B (optionally including elements other than B); in another embodiment, B without A (optionally including elements other than A); in yet another embodiment, both A and B (optionally including other elements); and so forth.

[0231] As used in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" is inclusive, i.e., It should be construed to include at least one, including more than one, of a number or list of elements, and optionally further items not listed. Only explicitly indicated items, such as "only one of" or "exactly one of," or "consisting of," when used in the claims, means including exactly one of a number or list of elements. In general, the term "or" as used herein will only be construed as indicating exclusive alternatives (i.e., "one or the other but not both") when preceded by a term of exclusivity, such as "either," "one of," "only one of," or "exactly one of." When used in the claims, "consisting essentially of" has its ordinary meaning as used in the field of patent law.

[0232] As used in the specification and claims, the phrase "at least one" in reference to a list of one or more elements should be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements, and not necessarily excluding combinations of elements in the list of elements. This definition also allows for elements to be optionally present other than elements specifically identified in the list of elements, meaning related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of A and B" (equivalently, "at least one of A or B," or, equivalently, "at least one of A and / or B") can mean, in one embodiment, at least one, including optionally more than one, A (optionally including elements other than B) in the absence of B; in another embodiment, at least one, including optionally more than one, B (optionally including elements other than A) in the absence of A; in yet another embodiment, at least one, including optionally more than one, A and at least one, including optionally more than one, B (optionally including other elements); etc.

[0233] Throughout the claims as well as in the specification, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," and the like, are intended to be open-ended, i.e., to mean inclusive, but not limited to, the following. Only the transitional phrases "consisting of" and "consisting essentially of" are closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03. [Explanation of symbols]

[0234] 100 ... above cell management system 112 ... Multiplex switch device 114 ... Controller 116, 360 … sensor 120, 130, 140, 150…Battery 121~124, 131~132, 141~142, 151~152 ... above cell set 121A~121C, 321A~321C … Electrochemical cells 210 ... Battery pack 218 … Switching control system 300 ... Battery management system 310 ... Cathode 312 ... Anode 314 … electrolyte 316 ... Storage structure 318A, 318B … Surface of containment structure 320 ... cathode active surface 321~325 … Multi-cell block 322 ... Anode active surface 326 ... Battery cell block arrangement and balance switch configuration 327 … Battery Management Microcontroller 328 … Battery System Interface 329…Battery power terminal 332 ... Substrate 334 ... Pressure distributor 336 … Pressure transmitter 340 ... Pressure distributor surface 342 ... Surface of an electrochemical cell

Claims

1. An electrochemical cell; and at least one controller configured to control the cell such that, during at least a portion of a charge cycle, the cell is charged at a charge rate or charge current that is lower than a discharge rate or discharge current of at least a portion of a previous discharge cycle; 1. An electrochemical cell management system comprising:

2. 10. The electrochemical cell management system of claim 1, wherein said discharge rate or current is at least two times higher than said charge rate or current.

3. The electrochemical cell management system of any one of claims 1 to 2, wherein the discharge rate or discharge current is four times higher than the charge rate or charge current.

4. the average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle; and 10. The electrochemical cell management system of claim 1, wherein an average discharge rate or average discharge current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is at least two times higher than an average charge rate or average charge current during the charge cycle.

5. 5. The electrochemical cell management system of claim 4, wherein an average discharge rate or average discharge current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is 4 times higher than an average charge rate or average charge current during the charge cycle.

6. The electrochemical cell management system of any one of claims 1 to 5, wherein the at least one controller is configured to control charging of the cells based on at least one characteristic of the cells.

7. The electrochemical cell management system of claim 6 , wherein the at least one controller is configured to monitor at least one characteristic of the cell.

8. The electrochemical cell management system of any one of claims 1 to 7, wherein the at least one controller is configured to direct the discharge of the cells.

9. The electrochemical cell management system of any one of claims 6 to 8, wherein the at least one characteristic of the cell includes at least a portion of the discharge history of the cell.

10. The electrochemical cell management system of any one of claims 6 to 9, wherein the at least one characteristic of the cell comprises at least one morphological characteristic of the cell.

11. The electrochemical cell management system of any one of claims 1 to 10, wherein the at least one controller is configured to direct the discharge of the cell at the end of a discharge cycle of the cell.

12. 12. The electrochemical cell management system of claim 1, wherein the at least one controller is configured to direct discharge of the cell during a discharge cycle of the cell and / or at the end of a charge cycle of the cell.

13. The electrochemical cell management system of any one of claims 1 to 12, wherein the at least one controller is configured to induce discharging of the cells before and / or after a charging step of the cells.

14. 13. The electrochemical cell management system of any one of claims 1 to 12, wherein the at least one controller is configured to direct discharge of the cell at a first rate or first current through at least a threshold capacity of the cell just prior to initiation of a cell charging process that charges the cell slower than the first rate or first current.

15. The electrochemical cell management system of any preceding claim, wherein the at least one controller comprises at least one processor.

16. The electrochemical cell management system of any preceding claim, wherein the cells comprise a lithium metal electrode active material.

17. controlling the electrochemical cell such that during at least a portion of a charge cycle, the electrochemical cell is charged at a charge rate or charge current that is lower than a discharge rate or discharge current during at least a portion of a previous discharge cycle; 23. A method for managing an electrochemical cell comprising:

18. 20. The method of claim 17, wherein the discharge rate or current is at least two times higher than the charge rate or current.

19. the average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle; and 20. The method of claim 17, wherein an average discharge rate or average discharge current during a previous discharge cycle during which the cell discharges at least 5% of its discharge capacity is at least two times higher than an average charge rate or average charge current during the charge cycle.

20. A method of managing an electrochemical cell according to any one of claims 17 to 19, comprising controlling charging of the cell based on at least one characteristic of the cell.

21. The at least one characteristic is At least a portion of the discharge history of the cell; and At least one morphological characteristic of the cell.

21. The method of claim 20, further comprising at least one of:

22. A method of managing an electrochemical cell according to any one of claims 20 to 21, comprising monitoring at least one characteristic of the cell.

23. A method of managing an electrochemical cell according to any one of claims 17 to 22, comprising inducing discharge of the cell.

24. A method of managing an electrochemical cell according to any one of claims 17 to 22, comprising inducing discharge of the cell at the end of a discharge cycle of the cell.

25. A method of electrochemical cell care according to any one of claims 17 to 22, comprising inducing a discharge of the cell before and / or after the step of charging the cell.

26. The electrochemical cell management method of any one of claims 17 to 25, wherein the cell comprises a lithium metal electrode active material.

27. an electrochemical cell, and At least one controller Equipped with The at least one controller: monitoring at least one characteristic of the cell; and Directing the discharge of the cell and / or controlling the charge rate or charge current of the cell based on at least one characteristic of the cell. It is configured as follows: The at least one characteristic is At least a portion of the discharge history of the cell; and At least one morphological characteristic of the cell.

1. An electrochemical cell management system comprising:

28. the at least one characteristic includes at least one morphological characteristic of the cell including at least one rate of increase in thickness and / or pressure of the cell; and 28. The electrochemical cell management system of claim 27, wherein the at least one controller is configured to direct discharge of the cell and / or control a charge rate or current of the cell based on at least one rate of increase of thickness and / or pressure of the cell.

29. 28. The electrochemical cell management system of claim 27, wherein the at least one controller is configured to direct discharge of the cell at the end of a discharge cycle of the cell based on at least one characteristic of the cell.

30. 30. The electrochemical cell management system of any one of claims 27 and 29, wherein the at least one controller is configured to direct discharge of the cell during a discharge cycle of the cell and / or at the end of a charge cycle of the cell based on at least one characteristic of the cell.

31. 31. The electrochemical cell management system of any one of claims 27 and 29-30, wherein the at least one controller is configured to direct discharging of the cells before and / or after a charging step of the cells based on at least one characteristic of the cells.

32. 32. The electrochemical cell management system of any one of claims 27 and 29-31, wherein the at least one controller is configured to direct discharge of the cell at a first rate or first current through at least a threshold capacity of the cell just prior to initiation of a cell charging step of charging the cell slower than a first rate or first current based on at least one characteristic of the cell.

33. The average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle, and 33. The electrochemical cell management system of any one of claims 27, 29, and 31-32, wherein an average discharge rate or average discharge current during discharging at least 5% of the discharge capacity of the cell during a previous discharge cycle is at least two times higher than an average charge rate or average charge current during a charge cycle.

34. 34. The electrochemical cell management system of claim 33, wherein an average discharge rate or current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is 4 times higher than an average charge rate or current during a charge cycle.

35. The electrochemical cell management system of any one of claims 27 to 34, wherein the cells comprise lithium metal electrode active material.

36. an electrochemical cell, and at least one controller configured to induce discharging of said cells before and / or after a charging step of said cells; An electrochemical cell management system comprising:

37. 37. The electrochemical cell management system of claim 36, wherein the at least one controller is configured to direct discharge of the cell while the cell is connected to a charging device.

38. The at least one controller The average discharge rate or average discharge current is higher than the previous discharge cycle, and Higher than the average charge rate or average charge current of the previous charge cycle The electrochemical cell management system of any one of claims 36 to 37, configured to induce discharge of the cells at a rate or current that is at least one of:

39. 39. The electrochemical cell management system of any one of claims 36 to 38, wherein the at least one controller is configured to direct discharge of the cell during a discharge cycle of the cell and / or at the end of a charge cycle of the cell.

40. 39. The electrochemical cell management system of any one of claims 36 to 38, wherein the at least one controller is configured to induce discharge of the cell at a first rate or first current through at least a threshold capacity of the cell, and a charge cycle of the cell charges the cell slower than the first rate or first current.

41. 39. The electrochemical cell management system of any one of claims 36 to 38, wherein the at least one controller is configured to control the cells such that, during at least a portion of a charge cycle, the cells are charged at a charge rate or charge current that is lower than a discharge rate or discharge current of at least a portion of a previous discharge cycle other than an induced discharge.

42. The average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle, and 42. The electrochemical cell management system of claim 41, wherein an average discharge rate or current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is at least two times higher than an average charge rate or current during a charge cycle.

43. 43. The electrochemical cell management system of claim 42, wherein an average discharge rate or current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is 4 times higher than an average charge rate or current during a charge cycle.

44. The electrochemical cell management system of any one of claims 36 to 43, wherein the cells comprise lithium metal electrode active material.

45. The electrochemical cell management system of any one of claims 36 to 44, wherein the at least one controller is configured to direct discharge based on at least one characteristic of the cell.

46. The at least one characteristic is At least a portion of the discharge history of the cell; and At least one morphological characteristic of said cells.

46. ​​The electrochemical cell management system of claim 45, comprising at least one of:

47. The electrochemical cell management system of any one of claims 45 to 46, wherein the at least one controller is configured to monitor at least one characteristic of the cell.

48. Inducing a discharge of the electrochemical cell before and / or after the charging process of the electrochemical cell A method for managing an electrochemical cell comprising:

49. 49. The method of electrochemical cell management of claim 48, wherein inducing discharge of the cell comprises inducing discharge of the cell while the cell is connected to a charging device.

50. The average discharge rate or average discharge current is higher than the previous discharge cycle, and Higher than the average charge rate or average charge current of the previous charge cycle Inducing discharge of the cell at a rate or current that is at least one of: The electrochemical cell management method according to any one of claims 48 to 49, comprising:

51. Inducing discharge of the cell during a discharge cycle of the cell and / or at the end of a charge cycle of the cell. The electrochemical cell management method according to any one of claims 48 to 50, comprising:

52. Inducing a discharge of the cell at a first rate or a first current through at least a threshold capacity of the cell. Including, 52. The method of claim 48, wherein the step of charging the cell charges the cell slower than the first rate or first current.

53. controlling the cell such that during at least a portion of a charge cycle, the cell is charged at a charge rate or charge current that is lower than a discharge rate or discharge current during at least a portion of a previous discharge cycle other than an induced discharge; The electrochemical cell management method according to any one of claims 48 to 50, comprising:

54. The average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle, and 54. The method of claim 53, wherein an average discharge rate or average discharge current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is at least two times higher than an average charge rate or average charge current during a charge cycle.

55. 55. The method of claim 54, wherein an average discharge rate or average discharge current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is 4 times higher than an average charge rate or average charge current during a charging step.

56. The electrochemical cell management method of any one of claims 48 to 55, wherein the cell comprises a lithium metal electrode active material.

57. A method according to any one of claims 48 to 56, wherein the at least one controller is configured to direct discharge based on at least one characteristic of the cell.

58. The at least one characteristic is At least a portion of the discharge history of the cell; and At least one morphological characteristic of the cell.

58. The method of claim 57, comprising at least one of:

59. monitoring at least one characteristic of said cell; The electrochemical cell management method according to any one of claims 57 to 58, comprising:

60. monitoring at least one characteristic of the electrochemical cell; and directing discharge of the cell and / or controlling a charge rate or a charge current of the cell based on at least one characteristic of the cell. Including, The at least one characteristic is At least a portion of the discharge history of the cell; and At least one morphological characteristic of the cell.

2. A method of managing an electrochemical cell, comprising:

61. the at least one characteristic includes at least one morphological characteristic of the cell, including at least one rate of increase in thickness and / or pressure of the cell; and 61. The electrochemical cell management method of claim 60, wherein inducing discharge of the cell and / or controlling a charge rate or charge current of the cell comprises inducing discharge of the cell and / or controlling a charge rate or charge current of the cell based on a rate of increase of at least one of a thickness and / or a pressure of the cell.

62. inducing discharge of the cell at the end of a discharge cycle of the cell based on at least one characteristic of the cell.

61. The method of claim 60, comprising:

63. directing discharge of the cell during a discharge cycle of the cell and / or at the end of a charge cycle of the cell based on at least one characteristic of the cell.

63. The method of managing an electrochemical cell according to any one of claims 60 and 62, comprising:

64. Inducing a discharge of the cell before and / or after the charging step of the cell based on at least one characteristic of the cell. The electrochemical cell management method according to any one of claims 60 and 62 to 63, comprising:

65. inducing a discharge of the cell at a first rate or a first current through at least a threshold capacity of the cell immediately prior to initiating a charging step of the cell, the charging step charging the cell slower than a first rate or a first current based on at least one characteristic of the cell. The electrochemical cell management method according to any one of claims 60 and 62 to 64, comprising:

66. The average discharge rate or average discharge current during the previous discharge cycle is less than or equal to the average charge rate or average charge current during the charge cycle, and 66. The method of claim 60, 62, or 64-65, wherein the average discharge rate or average discharge current during the previous discharge cycle during which the cell discharged at least 5% of its discharge capacity is at least two times higher than the average charge rate or average charge current during the charge cycle.

67. 67. The method of claim 66, wherein an average discharge rate or average discharge current during discharging at least 5% of the cell's discharge capacity during a previous discharge cycle is 4 times higher than an average charge rate or average charge current during a charge cycle.

68. 68. The method of claim 60, wherein the cell comprises a lithium metal electrode active material.

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