System and method for battery charging

Abstract

Methods and systems are presented for charging (recharging) one or more battery cells by generating a harmonically tuned charging signal, which may include pulses of a charging signal. The harmonically tuned charging signal includes or otherwise corresponds to one or more harmonic frequencies associated with optimal energy transfer based on the real and / or imaginary values ​​of the battery cell's energy transfer. In one example, one or more harmonic frequencies, sometimes commonly referred to as harmonics, may be associated with the battery cell's lowest real impedance value. Aspects involve optimizing the charging signal corresponding to one or more harmonics associated with the battery cell's lowest real or resistive and / or lowest imaginary or reactive impedance value. Such a charging signal can improve efficiency when charging the battery cell by reducing energy lost due to high impedance at the battery cell's electrodes.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to systems and methods for charging one or more battery cells, and more specifically to systems and methods for generating high efficiency and / or fast charging signals for charging one or more battery cells.

[0002]

Cross - Reference to Related Applications

Background Art

[0003] Many electric devices, such as power tools, vacuum cleaners, portable electronic devices (such as mobile phones, tablets, wireless speakers, etc.), and electric vehicles, use rechargeable batteries as an operating power source. Rechargeable batteries are limited by a finite battery capacity and must be recharged when depleted. Recharging the battery can be inconvenient because the electric device is often stationary and must be connected to a wall outlet or other power source while the battery is being recharged. In the case of a vehicle, recharging a completely depleted battery can take several hours, depending, among other factors, on the battery capacity and the available charging power. Thus, significant effort has been devoted to developing fast charging technologies to reduce the time required to recharge the battery. However, fast recharge systems are typically inefficient, while slower recharge systems extend the recharge operation and defeat the basic purpose of a quick return to operation.

[0004] It should be noted that there seems to be an error in the date in the original text where it says "filed on April 17, 2020" in item

[11] , which is inconsistent with the context. It should probably be "filed on April 17, 2020" in the original text. The translation has been made based on the corrected date assumption. If this is not what you intended, please provide the correct information.Batteries also tend to degrade over time based on various factors, particularly the charge and discharge cycles and the depth of discharge and overcharging. That is, efforts are focused on optimizing charging to maximize battery life while utilizing as much battery capacity as possible, as well as on charging speed, and on avoiding over-discharging or overcharging the battery. These various objectives often conflict, and charging systems may optimize some attributes at the expense of others.

[0005] Perhaps at its simplest level, conventional battery charging involves applying a DC charging current to the battery cell, as shown in Figure 1A. Power supply 102 can be a direct current (DC) voltage source to provide the DC charging current to the battery cell 104. Other types of power supplies, such as current-controlled sources, may also be used. However, various battery types may simply accept too much current, potentially damaging the cell. Figure 1A shows a schematic of a simple circuit 100 for recharging a single-cell battery. For the sake of simplification, other components of the circuit, such as an ammeter, voltmeter, and controller, are not shown. Generally, the battery cell 104 can be recharged by applying a DC signal from a controllable power supply 102. The application of a charging signal to the electrodes of the battery cell 104 causes a reverse flow of electrons through the battery to replenish the storage concentration of charge carriers (such as lithium ions in the case of lithium-ion type battery cells) at the anode.

[0006] Pulse charging has also been explored. Figure 1B shows a typical graph 110 of a conventional DC voltage signal 122 applied to a battery cell 104 for recharging a battery generated by a power source 102. This graph shows the input voltage 112 versus time 114 of the charging signal 122. Generally, the power source 102 can be controlled to provide repetitive pulses 122 to the electrodes of the battery cell 104 for recharging the battery cell. In particular, the power source 102 can be controlled to provide a repetitive square wave signal (shown as pulse 116 followed by pulse 118) to the battery cell 104. The peaks of the square wave pulses 116, 118 can be lower than or equal to a voltage threshold 120 corresponding to the operating constraints of the voltage source 102. A typical charging signal used to recharge the battery cell 104 can be applied during the charging period, with some remaining duration between the application of the charging signal. The operation of circuit 100 thus generates the power recharge signal 122 illustrated in Figure 1B in a repetitive square wave pattern.

[0007] However, in some cases, applying a square wave charging signal 122 to recharge the battery cell 104 may degrade the battery cell's lifespan under recharging conditions or introduce inefficiencies into the battery recharging process. For example, the sudden application of charging current to the electrodes of the battery cell 104 (typically the anode) (i.e., the steep leading edge 124 of the square wave pulse 116) has been found to cause high initial impedance across the battery terminals. The same problem may arise with other pulse charging where a high frequency (steep) leading edge is present. Figure 1C shows a graph of estimated real impedance values ​​of the battery cell 104 against the corresponding frequencies of the recharge signal applied to the battery cell according to one embodiment. In particular, graph 150 shows a plot of real impedance values ​​(axis 154) against a logarithmic frequency axis (axis 152) of the frequency of the input signal to the battery cell 104. Plot 150 shows real impedance values ​​across the electrodes of the battery cell 104 at various frequencies of the recharge power signal used to recharge the battery. The shape and measurements of plot 150 may vary based on factors such as battery type, battery charge state, battery operating constraints, and battery temperature. Nevertheless, a general understanding of the battery characteristics under charge can be obtained from plot 158. In particular, the real impedance values ​​encountered at the electrodes of battery cell 104 may vary based on the frequency of the power charging signal supplied to the battery, with the real impedance values ​​328 increasing as the frequency of the charging signal increases after the frequency associated with the lowest impedance. For example, at frequency f Sq The input power signal to battery cell 104 at 162, and the impedance at the frequencies immediately preceding and following it, are f Min Compared to the impedance at lower frequencies, the battery cell 104 electrode may introduce a relatively high real impedance of 160.

[0008] Returning to the square wave charging signal 122 in Figure 1B, the high frequencies of the signal may be present at the corners of the square wave pulse 116. In particular, the sharp leading edge 124 of the charging signal is determined by high-frequency harmonics, as is the case when using a conventional inverse pulse scheme, as is the case when using a square wave pulse. As shown in graph 150 in Figure 1C, the battery has a relatively high impedance in response to high-frequency harmonics. [Overview of the project] [Problems that the invention aims to solve]

[0009] The charging signal associated with high impedance at the battery cell electrodes can result in numerous inefficiencies, including capacity loss, heat generation, and an imbalance in electrokinetic activity throughout the battery cell, undesirable electrochemical responses at the charging boundary, and degradation of materials within the battery cell 104, which may damage the battery and degrade the battery cell's lifespan. Furthermore, cold starting the battery with fast pulses limits the introduction of Faraday activity as the capacitive charging and diffusion processes begin. During this time, proximal lithium reacts and is rapidly consumed, leaving a period of undesirable side reactions and diffusion-limiting conditions that adversely affect the health of the cell and its components. These and other inefficiencies are particularly detrimental during fast recharging of the battery cell 104, which often involves relatively high currents.

[0010] Various aspects of the disclosure of this invention have been considered and developed, with these considerations in particular. [Means for solving the problem]

[0011] One aspect of the disclosure of the present invention relates to a method for charging an electrochemical device. The method may include the steps of: accessing a harmonic profile that describes the relationship between at least one harmonic and the impedance of the electrochemical device; and controlling the energy flux at the electrodes of the electrochemical device, wherein the energy flux is at a harmonic associated with the lowest impedance value of the electrochemical device.

[0012] In various implementations, harmonics may be associated with the lowest real impedance value of an electrochemical device, with the lowest imaginary impedance value of an electrochemical device, with a combination of real and imaginary impedance values ​​of an electrochemical device, with a combination of absolute values ​​of real and imaginary impedance values ​​of an electrochemical device, and / or with a combination of real impedance values ​​tuned by a first weighting value and imaginary impedance values ​​tuned by a second weighting value.

[0013] In some implementations, a method for charging an electrochemical device may further include the steps of acquiring a change in the minimum impedance value and controlling the energy flux at the electrodes of the electrochemical device at new harmonics associated with the change in the minimum impedance value. The method may also include the steps of detecting frequencies associated with parasitic losses in the electrochemical device and excluding harmonics associated with the detected frequencies of parasitic losses when acquiring the change in the minimum impedance value.

[0014] In many more implementations, the electrochemical device may comprise one of a half-cell battery, a cell battery, multiple batteries connected in parallel, or multiple batteries connected in series. The energy flux may comprise one of a charging current, a discharging current, a charging voltage, a discharging voltage, a charging power, or a discharging power.

[0015] The method may also include steps of controlling a portion of the energy flux in harmonics associated with the conductance or susceptance value admittance of an electrochemical device, and / or measuring the real and imaginary impedance values ​​of the electrochemical device while the energy flux is being applied to the electrodes of the electrochemical device. In some implementations, the harmonics may be associated with a minimum impedance value and have upper frequency limits for harmonics within a range associated with the minimum impedance value. The energy flux may comprise a leading-edge portion corresponding to the minimum impedance value of the electrochemical device, a body portion having a controlled magnitude value following the leading-edge portion, and / or a trailing-edge portion having a voltage value lower than the transient voltage corresponding to zero current flow in the electrochemical device.

[0016] Another aspect of the disclosure of the present invention relates to a method for charging an electrochemical device, comprising the steps of: accessing a harmonic profile that describes the relationship between at least one harmonic and the energy transfer of the electrochemical device; and controlling the energy flux at an electrode of the electrochemical device, wherein the energy flux is at a harmonic associated with the optimal energy transfer based on real and imaginary values ​​of the energy transfer at that electrode.

[0017] In some implementations, the real value of energy transfer can be a real impedance, the imaginary value of energy transfer can be an imaginary impedance, and / or the real value of energy transfer can be a conductance value, and the imaginary value of energy transfer can be a susceptance value.

[0018] A further aspect of the disclosure of the present invention relates to a battery charging system comprising a charge signal shaping circuit and a controller that controls the charge signal shaping circuit to determine the mode of the charge signal to an electrochemical device based on the relationship between the frequency components of the charge signal and the impedance, using the relationship between the frequency components of the charge signal and the impedance.

[0019] In some implementations, the system may further include a power source that provides a power signal, and the step of controlling the charge signal shaping circuit includes a step of extracting energy from the power signal and providing it to the charge signal. The charge signal shaping circuit may include one or more first shaping inductors communicating with a power rail, and / or first switching devices communicating between one or more first shaping inductors and electrodes of an electrochemical device. The charge signal shaping circuit of the system may also include one or more second shaping inductors communicating with electrodes of an electrochemical device, and / or second switching devices communicating between one or more second shaping inductors and a power rail.

[0020] In some implementations, a battery charging system controller transmits a first control signal to a first switching device and a second control signal to the first switching device, shaping a charging signal to the electrochemical device based on harmonics associated with the lowest impedance value of the electrochemical device. The system may also include a power supply that is electrically communicating with a power rail, the power supply being either a voltage-controlled or current-controlled power supply, and / or an impedance measuring circuit that communicates with the controller, the controller transmitting an impedance control signal to obtain an impedance measurement of the electrochemical device.

[0021] A further aspect of the disclosure of the present invention relates to a battery cell charging system comprising a charge signal shaping circuit comprising one or more inductors and a switching device connected in series with one or more inductors, wherein one or more inductors are in electrical communication with a power rail and the switching device is in electrical communication with a battery cell, and a controller that provides the switching device with a control signal for shaping a charge signal from the power rail to an electrochemical device based on harmonics associated with the lowest impedance of the electrochemical device.

[0022] In some implementations, the battery cell charging system may further include one or more second inductors communicating with the battery cells, and a second switching device communicating with one or more second inductors, wherein the controller provides a pulse width correction signal to activate the second switching device to further shape the charging signal. [Brief explanation of the drawing]

[0023] [Figure 1A] This is a circuit diagram of a conventional circuit for charging battery cells. [Figure 1B] This is a signal diagram of a conventional DC voltage or current signal for recharging a battery cell. [Figure 1C] This is a graph of the estimated real impedance value of a battery cell for a corresponding frequency of a charging signal applied to the battery cell according to one embodiment. [Figure 2] This is a circuit diagram showing a circuit for charging a battery cell using a charging signal shaping circuit according to one embodiment. [Figure 3A] This is a graph of a sinusoidal cell charging signal having a frequency corresponding to the determined minimum real impedance value of a battery cell according to one embodiment. [Figure 3B] This is a graph of the measured real impedance value of a battery cell against the corresponding frequency of a charging signal applied to the battery cell according to one embodiment. [Figure 4] This is a circuit diagram showing a circuit for shaping a charging signal to a battery cell based on a frequency corresponding to the lowest impedance value according to one embodiment. [Figure 5] This flowchart illustrates a method for generating a charging signal to a battery cell based on a frequency corresponding to the lowest impedance value according to one embodiment. [Figure 6] This is a graph showing the square wave pulse and sinusoidal pulse of a battery charging signal superimposed according to one embodiment. [Figure 7A]This is a graph of the measured real impedance values ​​of a battery cell for the corresponding frequencies of a charging signal applied to the battery cell, representing the highest and lowest frequencies according to one embodiment. [Figure 7B] This is a signal diagram of a battery cell charging pulse shaped to have multiple frequencies corresponding to the highest and lowest frequency real impedance values ​​that are within acceptable limits based on the indicated impedance of the battery cell according to one embodiment. [Figure 8] This flowchart illustrates a method for generating a charging signal to a battery cell based on a frequency range corresponding to the highest and lowest real impedance values ​​of the battery according to one embodiment. [Figure 9A] This diagram shows a series of first molding charge pulse signals generated from a battery charging circuit according to one embodiment. [Figure 9B] This is a signal diagram of a series of second molding charge pulses generated from a battery charging circuit according to one embodiment. [Figure 10A] This is a signal diagram showing the real impedance value and imaginary impedance value of a battery cell according to one embodiment, illustrating the charge signal applied to the battery cell over time. [Figure 10B] This graph shows the measured real impedance value, imaginary impedance value, and absolute impedance value of a battery cell for a corresponding frequency of a charging signal applied to the battery cell according to one embodiment. [Figure 11] This is a signal diagram of a molded battery cell charging signal, including the leading edge portion and the main body portion, generated from a battery charging circuit according to one embodiment. [Figure 12A] This is a plot of the measured voltage drop across a battery cell in response to a charging signal applied to the battery cell according to one embodiment, and the measured current during battery cell charging. [Figure 12B] This is a plot of the measured voltage drop across a battery cell in response to a charging signal applied to the battery cell according to one embodiment, and the measured current during battery cell charging. [Figure 13]This is a plot of the measured current across a current-sensing resistor in response to a charging signal applied to a battery cell, and the voltage in the battery cell, against time, according to one embodiment. [Figure 14] This figure shows an example of a computer system that can be used to carry out embodiments of the disclosure of the present invention. [Modes for carrying out the invention]

[0024] Aspects of the disclosure of the present invention utilize the idea that conventional charging techniques often generate free harmonics, and that such harmonics alter the impedance to the charging signal applied to the battery. Furthermore, in many cases, various harmonics increase the impedance to the signal applied to the battery, adversely affecting charging efficiency, capacity retention rate, and cycle life. Similarly, harmonics can reduce the amount of chemical energy stored in the battery relative to the applied charging power, and the total admittance in the case of pulsed charging methods. Aspects of the disclosure of the present invention include a step of optimizing the charging signal corresponding to one or more harmonics associated with the lowest real impedance value or resistive impedance value and / or the lowest imaginary impedance value or reactance impedance value of the battery cell. Such a charging signal can improve efficiency when charging the battery cell by reducing the energy loss due to high impedance at the electrodes of the battery cell.

[0025] This specification discloses systems, circuits, and methods for charging (recharging) one or more battery cells. The terms charging and recharging are used synonymously in this specification. The systems, circuits, and methods discussed can transfer charging energy more efficiently to battery cells than conventional charging circuits and methods. Aspects of the disclosure of the present invention can provide several advantages, individually or in combination, compared to conventional charging. For example, the charging techniques described herein can reduce the rate at which the anode and / or cathode are damaged, reduce the heat generated during charging, and these reductions can have several subsequent effects, such as reducing anode and / or cathode damage, as well as cell damage, and reducing the risk of circuits igniting or short-circuiting. In other examples, the charging techniques described herein can enable the application of higher charging speeds to cells, and thus enable faster charging. The techniques described herein can optimize the charging speed and take into account other issues such as cycle life and temperature. In one example, the charging speed and parameters can be optimized to enable longer cell life and higher energy charging efficiency. In another example, which can be considered "rapid charging," the systems and methods disclosed in this invention provide an improved balance between charging speed and cell life with minimal heat generation. While conventional charging circuits have attempted to consider the efficiency of the charging circuit by focusing on its electronic devices, the systems, circuits, and methods disclosed in this invention provide an efficient battery charging signal when applied to charge battery cells.

[0026] In one example, various embodiments discussed herein charge a battery cell by generating a harmonic-tuned charging signal that may include pulses of a charging signal. The harmonic-tuned charging signal comprises or corresponds to one or more harmonic frequencies associated with optimal energy transfer based on the real and / or imaginary values ​​of the energy transfer of the battery cell. In one example, one or more harmonic frequencies, sometimes commonly referred to as harmonics, may be associated with the lowest real impedance value of the battery cell. In another example, the charging signal corresponds to one or more harmonics associated with both the real and imaginary impedance values ​​of the cell. In yet another example, the charging signal may correspond to harmonics corresponding to one or both of the conductance or susceptance of the battery cell's admittance. Since admittance is the reciprocal of impedance, references to impedance herein should be considered to also apply to admittance. In various other embodiments, the charging signal to the battery cell may be modified to remove harmonics corresponding to high impedance or low admittance of the battery cell. It will be recognized that relatively low impedance frequencies are considered when determining the harmonic components of a harmonic-tuned signal, as being associated with the lowest impedance does not necessarily mean that the charging signal contains harmonics of the lowest impedance, and may not necessarily have frequencies of the lowest impedance.

[0027] While this specification discusses many examples of harmonic tuned charging signals that can be applied to cells or battery cells, it should be acknowledged that the systems and methods described can be applied to batteries containing many different types of cells, as well as collections of cells coupled in various possible combinations such as parallel, series, and combinations of parallel and series. For example, the systems and methods discussed herein can be applied to batteries containing many cells arranged to give a given pack voltage, output current, and / or capacity. In other implementations, the systems and methods discussed herein can be applied to electrochemical cells containing half-cell structures. Generally, the terms battery cell or cell refer to individual electrochemical devices, while the terms battery or battery pack refer to one or more cells. In the case of more than one cell, as described above, the cells can be interconnected in various ways.

[0028] More specifically, systems and circuits for determining the frequency profile of a battery cell charging signal are described. In some cases, the frequency profile of the charging signal may change due to the battery's charge state, temperature, and other factors; therefore, the techniques discussed herein can periodically or otherwise evaluate or determine the frequency profile of the charging signal as charging progresses. In one example, the circuit can define, shape, modify, or otherwise generate a charging signal (e.g., charging current) corresponding to a determined harmonic or frequency profile of the charging signal. In one example, the control circuit can highlight or define portions of the charging signal corresponding to one or more harmonics associated with the minimum impedance value. As mentioned above, the charge state changes, and the temperature may change during recharging; therefore, the harmonic profile of the charging signal may change due to material properties, as well as chemical and electrochemical processes within the battery cell. Accordingly, in some cases, the circuit performs an iterative process of evaluating the harmonic profile of the charging signal (e.g., determining how the frequencies correspond to the impedance of the battery cell) and adjusting the charging signal applied to the battery cell based on this harmonic profile. This iterative process improves the efficiency of the charging signal used to recharge battery cells, thereby reducing the time required to recharge the battery, extending battery life (e.g., the number of charge and discharge cycles the battery undergoes), optimizing the amount of current used to charge the battery, and avoiding energy loss and inefficiency. Furthermore, for various reasons, one or more frequency components of the charging signal may not correspond to the lowest frequency. For example, when shaping a leading edge according to a profile, such a shaped leading edge may not correspond to the target frequency due to timing, the shaping circuit used, etc. In some cases, other factors such as energy transfer, temperature, and other issues may be important in selecting harmonics to include in or exclude from the charging signal, and may determine whether harmonics other than those associated with the lowest impedance are utilized.

[0029] To control the energy flux at the electrodes of an electrochemical device such as a battery, for example, to generate a harmonic-tuned charging signal with appropriate harmonic components, a battery cell recharging circuit may include one or more charge pulse shaping circuits and impedance measurement circuits, including both hardware and / or software components and / or application-specific integrated circuits. In one particular implementation, the charge pulse shaping circuit may include a filter circuit controllable by a pulse control signal. The filter circuit can prevent rapid changes in the charge pulses transmitted to the battery cell. In particular, the filter circuit can accept an input current square wave and shape the signal applied to the battery based on Z=jωL such that the current is limited at high frequencies and allowed to flow through the circuit at low frequencies. The selection of components by the filter circuit can shape the leading edge of the charge pulse so that it is associated with a frequency that maximizes the power supplied to the battery cell while limiting the inefficient harmonics present in conventional square wave power signals. Furthermore, the pulse control signal to the filter circuit may include the duration of each frequency-tuned charging pulse supplied to the battery cell. The charge signal shaping circuit may further include a current shaping circuit controllable by a current shaping control signal. In one embodiment, the current shaping circuit may remove or draw current from a charge pulse to change the amplitude of the charge pulse before the pulse is applied to the battery cell. This shaping portion may be involved in determining the trailing edge of the pulse, the pulse duration, the voltage level between pulses, and other functions. The circuit may further include a power recovery portion, such as a capacitor coupled to a power rail, which stores the drawn-up current and / or current from a current source and can use these currents to improve the efficiency of the recharge circuit in delivering charge current to the battery cell.

[0030] The systems, circuits, and methods discussed herein are applicable to charging any form of battery, which may include several cells connected in any way to charge battery cells and reach a desired capacity, voltage, and output current range, whatever the application in which the battery is used. Various embodiments discussed herein can be considered to provide rapid charging. In either or both situations, the circuit can be controlled to provide a recharge pulse that includes a rising leading edge shaped not to be the steep edge associated with a conventional square wave or other conventional pulse. In one example, the rising leading edge of the charge pulse may be based on a frequency determined to be associated with the lowest or near-lowest real impedance value of the battery cell. The charge pulse may be based on a combination of the lowest real and imaginary impedances of the cell being charged. In another example, the charge pulse may be based either alone or in combination with the conductance and / or susceptance or any other admittance aspect of the battery cell being charged. Yet another embodiment of the battery cell may be used therein, considering it as shaping the charge pulse. Generally, when considering real and imaginary impedance values, the present invention evaluates signal harmonics where multiple values, individually or in combination, have relatively low impedance. Conversely, in the case of admittance, the present invention evaluates harmonics where admittance has relatively high conductance and susceptance, individually or in combination.

[0031] If we briefly discuss pulses based on the lowest real impedance value, applying a rising leading edge associated with an almost lowest real impedance value can eliminate the inefficient or harmful high-harmonic components associated with conventional steep-edge pulse charging. Furthermore, the duration of a charging pulse can be controlled by the circuit to maximize or extend the amount of power applied to the battery within that pulse without exceeding one or two or more upper thresholds of the amplitude of the charging pulse, which could damage the battery and thereby affect its capacity or lifespan. In these schemes, a charging signal having a harmonic-tuned configuration, such as a frequency-shaped leading edge, can be applied by controlling the circuit to deliver the optimal amount of charging energy to the battery within each pulse while simultaneously removing high-frequency degrading harmonics from the signal. Thus, this shaped charging signal can reduce the impedance of various interfaces, including electrodes for receiving charging energy in the battery during charging of battery cells, thereby improving the efficiency and speed of battery recharging.

[0032] Figure 2 is a schematic diagram showing an exemplary circuit 200 for recharging a battery cell 204 using a charge signal shaping circuit 206 and an impedance measurement circuit 208 according to one embodiment. Generally, the circuit 200 may include a power supply 202 which can be a voltage source or a current source. In one particular embodiment, the power supply 202 is a direct current (DC) voltage source, but an alternating current (AC) source is also possible. More specifically, the power supply 202 may include a DC source that provides a unidirectional current, an AC source that provides a bidirectional current, or a power supply that provides a ripple current (such as an AC signal that is DC biased to make the current unidirectional). Generally, the power supply 202 provides a charge current that can be shaped and used to charge the battery cell 204. In one particular embodiment, the circuit 200 shown in Figure 2 may include a charge signal shaping circuit 206 that shapes one or more aspects of a charge signal for use in charging the battery cell 204. In one example, a circuit controller 210 may provide one or more inputs to the power signal shaping circuit 206 for controlling the shaping of the charge signal. These inputs can be used by the molding circuit 206 to convert the signal from the power supply 202 into a more efficient power charging signal for the battery cell 204. The operation and composition of the charging signal molding circuit 206 are described in more detail below.

[0033] In some cases, the charge signal shaping circuit 206 can modify the energy from the power supply 202 to generate a charge signal that at least partially corresponds to the harmonics associated with the lowest real impedance value of the battery cell 204. Within the factors, in particular, the impedance at any given charge current, voltage level, charge level, number of charge / discharge cycles, and / or temperature can be known, thereby characterizing the battery such that the impedance is not measured directly but is instead accessed from computer memory or the like.

[0034] In one example, circuit 200 may include a battery measurement circuit 208 connected to battery cell 204 to measure cell voltage and charging current, as well as other cell attributes such as temperature, and to measure or calculate the impedance across the electrodes of cell 204. A temperature sensor to obtain temperature measurements may be part of the impedance measurement circuit or placed separately. In some cases, the measurement circuit measures current and voltage in the battery and provides these measurements to another device, such as a controller or other processing device, which may be included in or separate from the impedance measurement circuit to calculate the impedance from these measurements. The measurement circuit may provide phase information regarding voltage and / or current. In one example, impedance may be obtained based on applied pulses. Impedance may be obtained as part of a routine that applies signals with various frequency attributes to generate impedance value ranges corresponding to various frequency attributes of the cell for performing cell characterization steps that can be performed periodically before, during, and during charging, and can be used in combination with lookup techniques and other techniques. The characteristics of battery cell 204 may vary based on various chemical or physical attributes of the cell, as well as the state of the cell, including the charge state and / or temperature of the cell. Therefore, the battery measurement circuit 208 can be controlled by the circuit controller 210 to determine various battery cell characteristics corresponding to various frequency attributes for characterizing the battery cell 204 over time, particularly during cell recharging, and further to determine the impedance from these characteristics. In some cases, the circuit controller can provide the real component of the impedance of the battery cell 204 to the charge signal shaping circuit 206 so as to define the charge signal harmonically (for example, so as to shape the energy from the power supply 202 into one or more charge pulses corresponding to harmonics associated with the lowest real impedance value of the battery cell 204). In another example, the circuit controller 210 can generate one or more control signals based on the received real impedance value and provide these control signals to the charge signal shaping circuit 206.The control signal can shape the charging pulse to include harmonic components associated with real impedance values, among other things, within its function. In yet another example, the charging signal shaping circuit 206 can modify the energy from the power supply 202 to generate a charging pulse that at least partially corresponds to harmonics corresponding to any other aspect of the conductance or susceptance component of the admittance of the battery cell 204 or any other aspect of the impedance in the battery cell. Thus, as presented above, the discussion of impedance including real and / or imaginary components of impedance can be applied to similar measurements of a battery cell, such as the conductance or susceptance component of the admittance of the battery cell.

[0035] Figure 3A is a graph 302 of a sinusoidal modified half-wave signal having a frequency corresponding to the determined lowest real impedance value of the battery cell 204, the components of which can be incorporated into the charging signal and can be generated by the circuit 200 in Figure 2. With a perfect sine wave, the peak voltage is excessively high for most conventional charging conditions. A half-sine wave is useful for this. Similarly, Figure 3A does not show a theoretically correct half-wave sine wave signal, with each pulse starting in a slightly tapered shape, contrary to the steep leading and trailing edges that a true half-sine wave is expected to use. Thus, these edges are gentler to reduce higher frequency harmonics. In this example, the signal can be a characterizing signal that can be used to generate the graph shown in Figure 3B when the frequency is changed. The frequency of the sine wave signal itself is at the frequency corresponding to the lowest real impedance of the battery cell during charging. More specifically, graph 302 shows a plot 314 of the input voltage axis 304 of the signal sent to the battery cell 204 against the time axis 306. In contrast to the square wave charging signal discussed above, the charging signal generated by circuit 200 may include a repeating sinusoidal charging signal sent to the battery cell 204. Although only two pulses (pulses 308, 310) are shown in Figure 3A, it should be acknowledged that a sequence of such pulses can be sent to the battery cell for a period of time sufficient to charge the battery cell to a certain level. In one example, the signal is controlled so that the signal wave has a voltage of or higher than the open-circuit voltage of the battery. The frequency of the charging signal may, and is more likely to, change over time, depending on the impedance of the battery cell and the controlled scheme implemented, which may also change over time as described above. As discussed herein, the frequency of the shaped pulses, as well as the sinusoidal wave, can be set to an impedance that is either the lowest impedance or, depending on the implementation, higher, lower, or both. Therefore, it is not necessary to set the frequency strictly to the lowest impedance. The sinusoidal pulse components 308, 310 of the charging signal 314 can be generated and continued to be transmitted to the battery cell 204 during the recharging operation of circuit 200.The frequency-tuned charging signal 314 can remove or suppress high-frequency components commonly present in conventional rectangular or pulsed charging signals, thereby reducing the impedance of the battery cell 204 to charging and improving the efficiency of the recharge operation. Furthermore, the charging signal 314 may include a settling or quiescent period 316 of some duration between pulses 308, 310. The duration of the settling period 316 can be adjustable or controlled by the circuit controller 210 and can be based on various aspects of the recharge operation of the battery cell 204, including but not limited to the total power provided by the pulse 308 immediately preceding the charging signal 314, the charge state of the battery cell 204, the measured or estimated temperature of the battery cell 204, the measured impedance of the battery cell 204, and / or hardware components used in the charging circuit. For example, the duration of the settling period 316 can be based on the processing speed of the circuit controller 210 to give the control circuit 210 enough time to determine one or more target values ​​for controlling the charging circuit 200. Pulses 308 and 310 may contain amplitudes smaller than the voltage threshold 312. The voltage threshold 312 can be based on certain aspects of the battery cell 204 and / or power supply 202, such as an upper voltage threshold or current threshold of the power supply and / or thermodynamic boundaries corresponding to the voltage, temperature, and current of the battery cell 204. In some cases, the voltage threshold 312 can be controlled by the circuit controller 210, as will be described in more detail below.

[0036] In one specific case, the frequency or harmonics of the sinusoidal pulse 308 of the charging signal 314 generated by the circuit 200 to recharge the battery cell 204 can be selected to suppress the impedance at the battery cell 204 to the lowest possible level, and the circuit controller 210 can apply this to the charging pulse. For example, Figure 3B is a graph 322 of the measured real impedance values ​​of the battery cell 204 against the corresponding frequencies of the charging signal applied to the battery cell according to one embodiment. In particular, graph 322 shows a plot of real impedance values ​​(axis 324) against the logarithmic frequency axis (axis symmetry 326) of the charging signal. Plot 328 shows the real impedance values ​​across the electrodes of the battery cell 204 at various frequencies of the sinusoidal charging signal. As shown in the figure, the real impedance values ​​328 can vary based on the frequency of the charging signal, with a general sharp increase in the real impedance values ​​328 at the highest frequencies. However, plot 334 of the real impedance values ​​for the battery cell 204 shows that f Min The lowest real impedance value 330 associated with a specific charging signal frequency, labeled as such, is also shown. The plot of real impedance values ​​334 for battery cell 204 may depend on many factors of the cell, such as the battery's chemical properties, charge state, temperature, and the composition of the charging signal. Therefore, the frequency f corresponding to the lowest real impedance value 330 of battery cell 204 is also shown. Min Similarly, 332 may depend on the characteristics of a specific battery cell 204 under charging conditions. Frequency f Min 332 may correspond to other aspects of the battery cell 204, such as the configuration of cells in a pack and the connections between cells in a pack.

[0037] Since the impedance of the battery cell 204 can convert the accepted charging current into heat or other inefficiencies, the step of generating sinusoidal charging pulses 308, 310 at or near the frequency 332 corresponding to the lowest real impedance value 330 for the battery cell 204 can improve the efficiency of energy application to the battery cell 204 for charging. In other words, frequency f MinThe step of shaping the pulses 308, 310 of the charging signal 314 to include 332 or nearby harmonics can improve the efficiency of the charging signal 314 to the battery cell 204 by reducing the energy consumed that is converted into heat due to the impedance of the battery cell 204. Thus, one implementation of the recharging circuit 200 in Figure 2 may include an impedance measurement circuit 208 connected to the battery cell 204 to determine various real impedance values ​​of the battery cell over a frequency range of the charging signal. The impedance measurement circuit 208 may include any known or future circuit configured to measure the impedance across the electrodes of the battery cell 204, including voltage and current sensors. Multiple impedance values ​​of the battery cell 204 can be measured and provided to the circuit controller 210 at various frequencies of the charging power signal, and the circuit controller 210 can then determine or estimate the lowest real impedance value of the curve 334 of the battery cell 204. The circuit controller 210 then determines the frequency f corresponding to the lowest real impedance 330 of the battery cell 204. Min One or more components of the charging signal shaping circuit 206 can be controlled to generate a series of sinusoidal charging pulses 308, 310 at 332 harmonics. As will be explained in more detail below, the circuit controller 210 performs an iterative process of measuring or otherwise determining an estimated real impedance value for the current state of the battery cell 204 at various times during the recharging session, and a new estimated frequency f Min The pulses 308 and 310 of the charging power signal 314 can be adjusted in accordance with 332. By controlling the circuit 200 to generate a charging signal 314 with harmonic frequencies for pulses 308 and 310 based on the determined or estimated lowest real impedance value, the energy of the charging signal 314 can be applied more efficiently to recharge the battery cell 204 while minimizing energy consumption from high impedance at the electrodes due to the high-energy portion of the charging signal.

[0038] One particular implementation of a circuit for charging a battery cell that utilizes shaping of a charging pulse is illustrated in FIG. 4. Circuit 400 can be controlled by controller 210 to shape a recharge signal to the battery cell based on a frequency f corresponding to a minimum impedance value. In one example, controller 210 can be a feedback control system that uses either a voltage amplifier or a current amplifier. Generally, controller 210 can be an analog controller, a digital controller, a microcontroller or microcomputer, or an application-specific integrated circuit (ASIC) such as a special specification integrated circuit. Controller 210 can be configured or implemented to perform one or more of the operations discussed herein for controlling the implementation of shaping circuit 400. Further, as discussed below, circuit 400 can consider the imaginary component of impedance, the conductance component of admittance, the susceptance component of admittance, or any combination thereof. More or fewer components can be included within circuit 400, and components can be replaced by other components of equal function. In some implementations, some components can be replicated in parallel to charge multiple cells in parallel or to provide a higher charge capacity to a given cell or cell arrangement. Circuit 400 of FIG. 4 is merely an example of a power signal shaping circuit that can be controlled to provide the harmonic sine wave charging signals discussed herein. Min It can be controlled by controller 210 to shape a recharge signal to the battery cell based on a frequency f corresponding to a minimum impedance value. In one example, controller 210 can be a feedback control system that uses either a voltage amplifier or a current amplifier. Generally, controller 210 can be an analog controller, a digital controller, a microcontroller or microcomputer, or an application-specific integrated circuit (ASIC) such as a special specification integrated circuit. Controller 210 can be configured or implemented to perform one or more of the operations discussed herein for controlling the implementation of shaping circuit 400. Further, as discussed below, circuit 400 can consider the imaginary component of impedance, the conductance component of admittance, the susceptance component of admittance, or any combination thereof. More or fewer components can be included within circuit 400, and components can be replaced by other components of equal function. In some implementations, some components can be replicated in parallel to charge multiple cells in parallel or to provide a higher charge capacity to a given cell or cell arrangement. Circuit 400 of FIG. 4 is merely an example of a power signal shaping circuit that can be controlled to provide the harmonic sine wave charging signals discussed herein.

[0039] Circuit 400 can include a power source 402 coupled to rail 442 to provide a charging signal to battery cell 404. Power source 402 can be any type of energy source including a DC voltage source, an AC voltage source, and a current source. In some cases, power source 402 can be controlled through an input (such as V CONT 434, etc.) to vary the amplitude of the energy waveform or pulse provided to circuit 400. For example, circuit controller 210 can perform operations such as activating the power source, selecting the amplitude of the power signal, selecting between a DC power signal and an AC power signal, etc. by control signal VCONT 434 can be supplied to power supply 402. In one particular example, power supply 402 receives the amplitude of the supplied charge signal V CONT 434 can be configured to adjust based on the voltage value of the signal.

[0040] A filter circuit 406 can be connected to a power rail 442 for receiving power generated by a power supply 402. The filter circuit 406 has a frequency f Min The system may include components that output a charging signal to the battery cell 404 in general, having a portion corresponding to 332. For example, the output signal from the filter circuit 406 has a frequency f corresponding to the lowest real impedance value determined above. MinThe leading edge may include 332 or a nearby harmonic. In some cases, the components of the filter circuit 406 are controllable through one or more pulse control signals 416 transmitted to the filter circuit by the circuit controller 210. In a particular example shown in Figure 4, the filter circuit 406 may include a first inductor 410 connected in series between the power rail 442 and the first transistor 412. The inductance value of the first inductor 410 will affect the shape of the pulse leading edge, so that its selection can be based particularly on the charging characteristics of the battery cell 404. The first transistor 412 may be connected to the first electrode of the battery cell 404. The first transistor 412 can receive an input signal such as the pulse control signal 416 and be operated as a switching device or switching component. Generally, the first transistor 412 can be any type of FET transistor or any type of controllable switch for connecting the first inductor 410 to the first electrode 440 of the battery cell 404. For example, the first transistor 412 may be an FET transistor whose drain is connected to the first inductor 410, whose source is connected to the battery cell 404, and whose gate is connected to the first inductor 410 to receive the pulse control signal 416. In one embodiment, the pulse control signal 416 may be provided by a circuit controller 210 to control the operation of the first transistor 412 as a switch that connects node 436 to the first electrode of the battery cell 404 when closed, and disconnects the connection between the inductor 410 and the battery cell 404 when open. Control of the first transistor 412 for generating charging pulses will be described in more detail below with reference to method 500 in Figure 5.

[0041] Generally, the first inductor 410 can be operated to prevent a sudden increase in the current transmitted to the battery cell 404 when connected to the battery cell through the first transistor 412. More specifically, the first inductor 410 can resist a sudden surge of current flowing through the inductor to the battery cell 404 (when the first transistor 412 is energized). This resistance to a sudden increase in current prevents a sharp leading edge to the pulse of the charging signal provided by the power rail 442, thereby reducing high-frequency harmonics that may occur in the battery cell 404 when a square wave input is applied. When energized in response to the signal 416 on the pulse control signal input to the transistor 412, current or other form of energy flux from the power rail 442 can be supplied to the battery cell 404 through the first inductor 410 and the first transistor 412 to charge the battery cell 404 while minimizing high-frequency noise effects. In some cases, the filter circuit 406 may further include a flyback diode 414 connected in parallel with the first inductor 410. The flyback diode 414 provides a return path for the energy flux provided by the power rail 442 when the first transistor switch 412 is open or not energized. For example, the first transistor 412 can be controlled via a pulse control signal 416 to stop the current from flowing through the power rail 442 to the battery electrodes 440. This current can then be transmitted back to the upper rail 442 through the flyback diode 414. A storage capacitor 432 can be connected between the upper rail 442 and ground or a common line, thereby allowing the current provided by the power rail 442 and returned through the flyback diode 414 during the period when the first transistor 412 is open to be supplied to the storage capacitor 432 through the upper rail 442.As will be explained in more detail below, to prevent energy loss in the circuit while the first transistor 412 is open, the energy stored in the storage capacitor 432 when the first transistor 412 is closed (e.g., in the next pulse of the charging signal) can be returned to the input of the upper rail 442 and the filter circuit 406, thereby further improving the efficiency of the circuit 400.

[0042] Figure 4 shows the components of a single filter circuit 406, but additional filter circuits having the same or similar configuration can be connected in parallel to filter circuit 406. For example, filter circuit 406 can have any number of additional filter circuits, up to a maximum of filter circuit N418, connected in parallel within the charging circuit 400. Each filter circuit 406, 418 can be independently controlled by the circuit controller 210 through individual pulse control signals 416 to filter out one or more harmonics from the current provided to charge the battery cell 404. In another example, more than one filter circuit 406 can be controlled by the same pulse control signal 416. One or more of the additional filter circuits 418 may include similar components of the same or different values. For example, the first inductor of filter circuit N418 may have a higher inductance value than the first inductor 410 of filter circuit 406. Generally, a higher inductance value of the first inductor 410 provides higher resistance to abrupt changes in the charging pulse, thereby creating a steeper leading edge of the charging pulse compared to an inductor of a lower value. In this way, the circuit controller 210 can control various filter circuits 406, 418 to shape the leading edge of the energy pulse supplied to the battery cell 404 by various inductance values ​​of the selected first inductor 410.

[0043] To further modify the pulses of the charging signal supplied to the battery cell 404, one or more input shaping circuits 420 can be connected to the first electrode 440 of the battery cell 404 (e.g., the anode or positive terminal). In particular, the input shaping circuit 420 may include a second inductor 424 connected between the first electrode 440 of the battery cell 404 and a second transistor 422. In one example, the second transistor 422 may be a FET transistor with its drain 444 connected to the second inductor 424, its source 446 connected to ground or a common line, and its gate receiving a control signal 426. Similar to the first transistor 412, the second transistor 422 may act as a switch connecting its drain 444 to a negative rail, ground, or a common line. The second transistor 422 may be controlled by an input control signal 426. In one embodiment, the shaping input signal 426 may be a high-frequency pulse width modification (PWM) signal that alternates between on and off states at a high frequency. For example, the PWM signal 426 can be operated at frequencies higher than 100 kHz, but it can be operated at any frequency. In response to the high-frequency switching PWM signal 426, the second transistor 422 can rapidly switch between energized (or "on") and de-energized (or "off") states. In this way, the operation of the second transistor 422 allows the energy from the charging pulses transmitted to the battery cell 404 to be drawn up to ground by the shaping circuit 420. The drawn-up current can be stored in the second inductor 424, and since the current in this inductor delays the voltage, the current does not flow to ground while it is stored in the second inductor 424. However, the off portion of the PWM signal 426 can close the transistor 422 quickly enough, and therefore, when the current leaves the second inductor 424, the transistor 422 is turned off, and most or none of the energy signal drawn up from the charging pulses is not transmitted to ground through the connection 446. Rather, the absorbed energy can be transmitted to the upper rail 442 through the flyback diode 430 and stored in the energy storage capacitor 432 for reuse by the charging circuit 400.

[0044] By extracting energy from the charging signal, the input molding circuit 420 can modify a portion of the amplitude of the charging pulse to shape or form the pulse to the battery 404. In particular, controlling the frequency of the PWM signal 426 can extract more or less energy from the charging signal. Furthermore, the load cycle of the PWM signal 426 can be selected or controlled to correspond to the modification of the charging pulse or the time required for shaping. In this way, in some cases, the PWM signal 426 provided by the circuit controller 210 can modify the charging signal from the filter circuit 406 to the battery cell 404. Similarly, like the filter circuit 406, one or more additional input molding circuits 428 can be connected in parallel with the input molding circuit 420. Each input molding circuit 420, 428 can be independently controlled by the circuit controller 210 through its individual PWM control signal 426. In another example, more than one molding circuit 420 can be controlled by the same PWM control signal 426. One or more of the additional input molding circuits 428 may include similar components of the same or different values. For example, the second inductor at the input of the shaping circuit N428 may have a higher or lower inductance value than the second inductor 424 at the input of the filter circuit 420. By controlling the pulse control signal 416 and the PWM signal 426 applied to the filter circuit 406 and / or the input shaping circuit 420, one or more pulses of the charging signal applied to the battery cell 404 can be shaped to achieve a harmonic charging signal. Additional shaping of the input charging signal can be controlled by the circuit controller 210 to further shape the profile of the signal pulses, as will be described in more detail below. In addition, various control signals of the circuit controller 210 can be used to control the manner of the charging signal provided to the battery cell 404. For example, these control signals can control the voltage at the battery cell 404, the current supplied to the battery cell, or the total energy or power supplied to the battery cell.Therefore, although this specification discusses controlling or shaping the charging signal to the battery cell, it should be acknowledged that any aspect of the charging signal can be controlled by the circuit controller 210.

[0045] The circuit 400 in Figure 4 may further include an impedance measurement circuit 408 connected to the battery cell 404. Generally, the impedance measurement circuit 408 measures the impedance characteristics observed at the electrodes of the battery cell 404. In one example, the impedance measurement circuit 408 may include a voltage sensor that measures the voltage across the electrodes of the battery cell 404 and a current sensor that measures the current to the battery cell. However, the impedance measurement circuit 408 may include any known or hereafter developed circuit for measuring the impedance of the battery cell 404. Furthermore, the impedance measurement circuit 408 can be controlled by the circuit controller 210 to measure the cell impedance at various times or periods. For example, the impedance measurement circuit 408 may be configured to measure the impedance of the battery cell 404 during a test period in which a charging signal is applied to the battery cell 404 over a certain frequency range. These measurements can be obtained and provided to the circuit controller 210 to determine the lowest real impedance for the battery cell 404 as discussed above with respect to graph 322 in Figure 3B.

[0046] The circuit controller 210 can use the circuit 400 of Figure 4 to shape the pulses of the charging signal to the battery cell based on a frequency corresponding to the lowest impedance value. In particular, Figure 5 shows a method 500 for generating a charging signal to the battery cell based on a frequency corresponding to the lowest impedance value according to one embodiment. The operation of method 500 can be carried out by the circuit controller 210 providing control signals to the power supply 402, the filter circuit 406, and / or the input shaping circuit 420 in particular to control various components of the circuit 400. Other circuit designs and components can be controlled by the circuit controller 210 to carry out one or more of the operations of method 500. Thus, although this specification describes the circuit 400 of Figure 4, the operation of method 500 can be carried out by any number of hardware components, software programs, or combinations of hardware and software components.

[0047] Starting with operation 502, the circuit controller 210 can select an initial frequency component for the charge pulse to be used to recharge the battery cell 404. For example, a sinusoidal charge pulse can be selected to avoid the inefficiency of a square wave charge pulse in recharging the battery cell 404. The initial frequency of the charge pulse can be selected by the circuit controller 210. In some cases, the selected frequency can be determined to suppress or reduce the real impedance in the battery cell 404 to the minimum during the initial charge of the battery. Initially, the circuit controller 210 may not know the real impedance of the battery cell 404 because the charge signal has not yet been applied to the battery and one or more characteristics (such as the charge state of the battery cell or other electrochemical aspects of the battery) may not be known. Therefore, the circuit controller 210 may select an initial frequency for the charge pulse to begin supplying energy to the battery cell 404. In one particular implementation, the circuit controller 210 can obtain the initial frequency for a charge pulse based on historical data of battery cell 404, historical data of other battery cells, historical data of the circuit controller 210, or other battery recharge data. For example, the circuit controller 210 can analyze past recharge sessions of battery cell 404 or other battery cells. Based on this analysis, the circuit controller 210 can determine the frequency f for battery cell 404, which has the lowest real impedance value of the battery cells. Min This can be estimated. The deeper the recharge session is analyzed, the better the best estimate can be determined that is associated with the estimated minimum real impedance value for battery cell 404 with respect to the initial frequency for the charge pulse. The initial selection frequency may not correspond to the actual minimum real impedance value for the charge state for battery cell 404, but can instead be based on one or more hysteretic real impedance measurements for the target battery cell or any other battery cell.

[0048] Once an initial frequency for the charging pulse is selected, the circuit controller 210 can control the pulse control signal input 416 and / or PWM signal input 426 of the charging circuit 400 to generate harmonic charging pulses for the battery cell 404. In particular, the circuit controller 210 can provide the pulse control signal 416 to activate the first transistor 412 for a first period. The activation of the first transistor 412 allows energy pulses to be transmitted from the power rail 442 to the battery cell 404. The first inductor 410 of the filter circuit 406 can resist abrupt increases in pulses received from the power rail 442 (e.g., square wave pulses) and output a leading edge (e.g., leading edge of a sinusoidal pulse) that is sloped toward transmission to the battery cell 404. The duration of the charging signal pulse can also correspond to the first period during which the first transistor 412 is activated and energized. Furthermore, the amplitude of the pulse can be the amplitude of the signal provided by the power supply 402 (when V CONT It is possible to correspond to the duration of a pulse signal controlled by 434 and / or through the pulse control signal 416. In particular, the duration for which the first transistor 412 is energized corresponds to the duration of the energy pulse supplied to the battery cell 404. In many cases, the circuit controller 210 can repeatedly start / stop the first transistor 412 to provide the battery cell 404 with a periodic, repeating pattern of energy pulses.

[0049] In addition to the leading edge and pulse duration, modifications to the energy pulse supplied to the battery cell 404 can be implemented by controlling the input shaping circuit 420. In particular, a PWM signal 426 can be provided to a second transistor 422 to rapidly start and stop the transistor, causing the input shaping circuit 420 to extract energy from the pulse and reduce the pulse amplitude at any point during the pulse duration. The frequency of the PWM signal 426 can control how much energy is extracted from the energy pulse signal and how much the profile is further modified. Precise control of the PWM signal 426 can reduce the pulse amplitude (by removing energy from the pulse) or increase it (by stopping transistor 422 so that energy is not removed from the pulse by the input shaping circuit 420), thereby generating a shaped pulse for charging the battery cell 404.

[0050] By controlling the input to circuit 400, such as pulse control signal 416 and / or PWM signal 426, the circuit controller 210 can generate sinusoidal pulses for charging the battery cell 404, similar to waveform 314 in Figure 3A, at a selected initial frequency. However, as mentioned above, the minimum real impedance in battery cell 404 may change during battery charging. For example, the charge state and temperature of battery cell 404 may change the minimum real impedance characteristics. By adjusting the frequency of the pulse charging signal to match the frequency corresponding to the minimum real impedance of battery cell 404 in the current state of the battery, an efficiency advantage in charging the battery can be obtained. Thus, in operation 506, the circuit controller 210 can measure the impedance of the battery cell at various frequencies to obtain a function of the real impedance value of the battery cell at various frequencies. In one embodiment, the circuit controller 210 can apply one or more test signals of various frequencies to battery cell 404 to determine the charging signal frequency corresponding to the measured minimum real impedance in battery cell 404. To determine the range of test signals to the battery cell 404, the frequency of the test signals can be predetermined by the circuit controller 210. For each test signal, the corresponding real impedance value in the battery cell 404 can be determined and / or stored. In addition to using many frequencies, constant current intermittent titration (GITT) technique can be used. Generally, GITT uses the properties of a rectangular pulse (which is the sum of sinusoidal frequencies across the spectrum) to reveal the complex impedance that can be used to determine the impedance of the battery cell 404.

[0051] In operation 508, the lowest real impedance value of the measured test impedance can be determined. For example, the circuit controller 210 can select the lowest real impedance value from the accepted test results as the lowest impedance value. In another example, the circuit controller 210 can analyze the accepted real impedance values ​​and extrapolate these values ​​to determine the lowest real impedance value. For example, the measurements may show that the real impedance value decreases for a series of increasing test frequencies, followed by measurements that increase for the next series of increasing test frequencies. The circuit controller 210 can determine that the lowest real impedance value for the battery cell 404 is associated with a frequency between a first set of increasing test frequencies and a second set of increasing test frequencies. In this context, the circuit controller 210 can estimate the lowest real impedance value for the battery cell 404 between these measurements. In operation 510, the circuit controller 210 can determine the frequency corresponding to the lowest real impedance value determined for the battery cell 404. For example, a graph 334 can be generated showing the real impedance value 324 of the battery cell 404 for a test signal frequency 326, and the lowest real impedance value 330 can be determined from this graph. From graph 334, the frequency corresponding to the lowest real impedance value 330 can be determined. Generally, the corresponding frequency can be determined using any correlation algorithm to determine the frequency of the input signal to the battery cell 404 that causes the lowest real impedance value.

[0052] In operation 512, the circuit controller 210 can determine whether the frequency corresponding to the lowest real impedance value of the measurement test impedance is different from the previously selected frequency at which the charging pulse is provided. If the circuit controller 210 determines that the corresponding frequency obtained from the application of the test signal to the battery cell 404 is different from the frequency at which the charging pulse is provided, the circuit controller 210 can select this corresponding frequency for additional pulses of the charging signal in operation 514. Furthermore, the circuit controller 210 can return to operation 504 and generate and provide an input signal to the molding circuit to adjust the frequency of the charging pulse to the battery cell to match the determined corresponding frequency. If the corresponding frequency is not different from the frequency at which the charging pulse is provided, the circuit controller 210 can maintain the frequency for the additional charging pulse in operation 514 and provide the corresponding control signal to the molding circuit in operation 504. As described above, by method 500 in Figure 5, the frequency corresponding to the lowest real impedance value for the battery cell can be selected for sinusoidal charging pulses to be generated to recharge the battery cell 204.

[0053] One potential drawback of using a sinusoidal charging signal is that each pulse of such a signal carries less charging energy compared to a square wave charging signal. This potential drawback can be particularly significant in fast charging situations where the goal is to supply the battery cell with the maximum amount of energy in the minimum amount of time. Graph 602 in Figure 6 provides an illustration of this potential drawback. Specifically, Figure 6 shows graph 602 of the input voltage value 604 over time 606 with superposition of square wave pulses 612, 614 and sinusoidal pulses 608, 610 of the battery charging signal. Generally, the area under each pulse illustrates the amount of charge that can be supplied to the battery for recharging. As discussed above, the area under the pulse represents the available charge, and it must be acknowledged that, generally, there are battery and charging attributes that interfere with the ability of all the energy of the rectangular pulses to be delivered to charge the cell. Nevertheless, the difference between the charge provided by the square wave pulses 612, 614 and the charge provided by the sinusoidal pulses 608, 610 is illustrated in hashed areas 616, 618. As shown in the figure, the sinusoidal pulses 608, 610 reduce the impedance in the battery due to the estimation of the selected harmonic frequencies discussed above, but may supply less charge to the battery per pulse than the square wave pulses 612, 614. Thus, charging based on the lowest impedance frequency can improve charging compared to other systems, but further improvements and optimizations may be useful.

[0054] One potential method for providing a battery-like charge with a select harmonic associated with the lowest real impedance value is to increase the amplitude of the charge pulses 608, 610. However, many batteries have characteristics that impose an upper threshold on the amplitude of the charge signal, and therefore simply increasing the amplitude of the sinusoidal pulse may not be advantageous for rapidly charging the battery cells. For example, the electrolyte in many batteries decomposes at certain power levels correlated with a voltage threshold, and the irreversibility of such a chemical reaction shortens the battery life. Such decomposition of the electrolyte may also occur when there is a sudden change in the recharge power signal applied to the battery electrodes. Other components of the battery may also decompose or be otherwise damaged in response to the sudden application of a power recharge signal. For example, high power signals may cause one or more permanent lumens to form across the solid electrolyte interface (SEI) layer of a lithium-ion battery, resulting in permanent spatial heterogeneity across the anode. The SEI layer may also increase in thickness in response to high power signals, reducing the efficiency of the battery. Furthermore, increasing the amplitude of the recharge power signal can cause the battery to generate heat faster than it can dissipate, sometimes leading to a high risk of battery damage and thermal runaway. Therefore, simply increasing the amplitude of pulses 608 and 610 may damage the battery during recharging.

[0055] An alternative method for increasing the amount of charging energy provided by sinusoidal pulses 608, 610 is to combine multiple harmonics to broaden the peak and / or tune the leading edge of the pulse to the lowest frequency of the target real impedance (and / or target the imaginary component of the impedance, as will be discussed in more detail below), while maintaining the pulse at or near the pulse peak where the sinusoidal pulse is normally expected to begin to decline. In one example, the methods and circuits discussed herein can be applied to provide the battery cell with a charging signal containing harmonics within the identified frequencies, determining a frequency range corresponding to one or more lowest real impedance values ​​of a battery cell. For example, Figure 7A is a graph 702 of the measured real impedance values ​​714 of the battery cell for the corresponding frequencies 706 of the charging signal applied to the battery cell. It must be recognized that these values ​​can be measured in real time, but can also be measured and stored, and therefore can not be measured in real time, can be characterized or derived from other information, can be measured but only periodically, can have the frequency set to any initial value and then adjusted in a feedback loop, can have the impedance estimated or extrapolated from other information, and much more. It must also be recognized that other aspects of the battery cell, such as imaginary impedance values, admittance values, and / or susceptance values, can also be measured or estimated and used to shape the charging pulse. The graph above shows the highest frequency 710 and the lowest frequency 708 over a range of values ​​that are acceptable lowest impedance values ​​but are not strictly located at the lowest impedance frequency value. Graph 702 in Figure 7A is similar to Graph 322 in Figure 3B discussed above in the sense that it represents a plot of the real impedance values ​​of the battery cell against the frequency of the charging signal provided to the battery. However, in this example, the frequency f corresponding to the lowest real impedance value 330 Min Instead of determining 332, the lowest frequency f RMin 708 and the highest frequency f RMaxThe frequency range defined by 710 can be determined near the lowest real impedance value of the battery 712 based on the allowable impedance value for charging the battery cell. The lowest frequency f widens the pulse profile to increase the amount of charge delivered to the battery cell during each pulse. RMin 708 and the highest frequency f RMax 710 can be selected and included within the generated battery charge signal pulse. By including multiple harmonics within the charge pulse of the power recharge signal based on a frequency range between acceptable impedance values, it is possible to provide a greater amount of charge to recharge the battery cell than is available from a single harmonic sine wave, while maintaining a lower impedance in the battery cell receiving the charge pulse.

[0056] Figure 7B shows the highest frequency f based on the real impedance value of a battery cell according to one embodiment. RMax 710 and the lowest frequency f RMin Figure 722 shows the signal of a battery cell charging pulse with multiple harmonics of frequencies corresponding to 708. Figure 7B is an example of a harmonic profile illustrating how various harmonics affect impedance. In this example, the harmonic profile shows the frequency range and real impedance. However, the harmonic profile can be as simple as the relationship between a single frequency and impedance during charging. Furthermore, impedance can be real, the absolute value of an imaginary number, and combinations thereof (as well as an analogue of admittance). This signal figure 722 shows the input voltage 724 versus time 726, including a maximum voltage threshold 730 beyond which battery damage may occur. In particular, the charging pulse 728 in Figure 722 can be generated based on the frequency range shown in graph 702 in Figure 7A. For example, the charging pulse 728 in Figure 7B has a minimum frequency f RMin 708 and the highest frequency f RMax This can include a range of harmonics that fall between 7 and 10. In one example, the lowest frequency f RMin 708 and the highest frequency f RMax 710 corresponds to the frequency f of the lowest real impedance value 712.Min 711 has the lowest frequency f RMin 708 and the highest frequency f RMax It is possible to base the charging pulse on the lowest real impedance value 712 for the battery cell, which is determined to be within 710. At each selected harmonic frequency within the charging pulse 728, the corresponding amplitude is determined based on the corresponding real impedance value of the battery at that frequency, which can result in a non-uniform, arbitrary-shaped charging pulse based on the harmonic content and / or amplitude. However, none of the selected amplitudes may exceed the upper voltage threshold or upper power threshold 730, which could damage the battery cell under recharging or cause the battery cell to overheat. By including the frequency range corresponding to the lowest real impedance value 712, the charging pulse can be expanded to apply a larger charge to recharge the battery while simultaneously maintaining a low impedance in the battery. In this way, a high charge amount, low impedance charging signal can be used to recharge the battery cell, thereby improving efficiency compared to other conventional pulse charging techniques, whether using a square wave recharge signal or otherwise.

[0057] Figure 8 is a flowchart illustrating a method for generating a charging signal to a battery cell based on a frequency range corresponding to the highest and lowest real impedance values ​​of the battery according to one embodiment. As described above, similar methods can be performed to generate a charging signal to a battery cell based on other aspects of the battery cell, such as imaginary impedance values, admittance values, and / or susceptance values. Similar to method 500 in Figure 5, method 800 in Figure 8 can be implemented by having the circuit controller 210 provide control signals to the power supply 402, the filter circuit 406, and / or the input shaping circuit 420 in particular to control various components of the circuit 400 in Figure 4. Other circuit designs and components can be controlled by the circuit controller 210 to implement one or more of the operation of method 500. Thus, although this specification describes the circuit 400 in Figure 4, the operation of method 500 can be performed by any number of hardware components, software programs, or combinations of hardware and software components.

[0058] When starting operation 802, the circuit controller 210 can acquire the lowest real impedance value for the battery cell. The step of acquiring the lowest real impedance value can be the same as above in the sense that the circuit controller 210 can measure or receive impedance measurements of the battery at various frequencies of the charging signal. The lowest real impedance value can be determined by a loop controller or by a process driven by the circuit controller 210. For example, the circuit controller 210 can have the circuit charge the battery at various frequencies, for example, over a frequency range, and measure the impedance of the battery cell 204 until the lowest impedance value for the battery cell is found. Such measurements (also referred to herein as harmonic profiles) can be acquired during the active charging of the battery cell, or acquired and stored in memory and operated in a lookup manner. For some batteries, the impedance measurement versus charging signal frequency can be the same as in graph 702 of Figure 7A. Similar to graph 702, the circuit controller 210 can determine the lowest real impedance value 712 of the battery cell based on multiple impedance measurements. The impedance measurement process involves acquiring and storing impedance values ​​at various frequencies, for example, at the frequency f at which the lowest frequency occurs. Min Impedance measurements can be obtained at frequencies higher and lower than 711.

[0059] In operation 804, the circuit controller 210 can select a value for the upper limit real impedance value 720 for the corresponding acceptable impedance value range. In particular, the circuit controller 210 can determine or provide an acceptable impedance value 716 in the battery cell based on the application of a charging signal. The acceptable impedance value 716 is not higher than the minimum impedance value and is the frequency f at which the minimum impedance occurs. Min711 is shown and described as a single acceptable impedance value that occurs at both higher and lower frequencies than 711. It must be acknowledged that the acceptable impedance value 716 may not be the same at higher and lower frequencies than the lowest impedance. Furthermore, the acceptable impedance 716 changes as charging progresses, and cell temperature changes may be based on the charging current level. The acceptable impedance value 716 can be higher than the lowest impedance value 712 determined above. For example, the circuit controller 210 may determine or provide the impedance value 716 as the acceptable impedance value for the charging signal. Generally, the acceptable impedance value 716 can be any impedance in the battery cell under recharging. However, a lower acceptable impedance value 716 may be selected or determined to limit the total impedance in the battery cell during the application of the charging signal. Furthermore, the upper limit impedance value 720 of the range is the frequency f at which the lowest impedance occurs. Min The impedance value can be one that occurs at a different frequency or combination of frequencies than 711. In many cases, the frequency f at which the lowest impedance occurs is... Min There will be frequency ranges above and below 711 that are higher than the lowest impedance 712 but lower than the acceptable impedance 716. For example, the acceptable impedance in this range will be at frequencies f higher than the frequency at which the lowest impedance occurs. RMaxThis can occur at location 710. Therefore, the circuit controller 210 can be configured to determine or select an upper impedance value 720 for the acceptable range by traversing the impedance value plot curve 714 from the lowest impedance value 712 to the right (increasing frequency) until it encounters an acceptable impedance value 716. However, in other implementations, the upper impedance value 720 for this range is a set difference from the lowest impedance value 712 (calculated and further considering other factors such as battery charge level and temperature, and a programmatic set delta from the lowest value). For example, the upper impedance value for range 720 can be determined as twice the lowest impedance value 712 or any other multiple of the lowest impedance value.

[0060] As shown in Figure 7A as a smooth curve, the shape of the plotted impedance curve 714 can include various instances of noise or other effects at various frequencies. For example, the plotted impedance value 714 can be generated at various signal amplitudes such that the plotted curve 714 can include dips, especially at higher frequencies, when the amplitude of harmonics is increased. Thus, plot 714 can be the sum of several different plots, each corresponding to a different segment of harmonic power. In such a situation, the frequency f corresponding to the lowest impedance 712... Min The 711 can remain relatively constant when the amplitude of its harmonics is increased to a predetermined value at which the impedance value begins to rise sharply.

[0061] Furthermore, the physical orientation of the cells within the pack (such as whether they are connected in parallel or series) can affect the impedance curve due to parasitic capacitance and inductive losses. For example, energy may jump from one cell to another over a short distance through the air in certain frequency bands, effectively traveling beyond the cells within the battery pack structure, and the current flow at this point may be further inhibited or permitted. The measured impedance at these frequencies may cause dips or areas where the impedance appears low when cells in the pack are jumped, thereby allowing for the determination of local minimum impedance values, particularly with respect to certain harmonics near higher frequencies. However, charging battery cells or battery packs at these higher frequencies cannot improve the efficiency of battery cell charging for the reasons mentioned above. Therefore, the frequency f corresponding to the lowest impedance 712 is... Min The step of determining 711 may include operations to exclude dips in impedance values ​​or relatively high-noise bands at higher frequencies due to parasitic losses in the battery buck. Such exclusion at higher frequencies can be achieved by selecting an inductor value 410 (or filter circuits 406, 418), or by including additional high-frequency filters included in the charging signal path within circuit 400. In one embodiment, the controller 210 may compare several parameters of the battery cell or battery buck, such as real and imaginary impedances, admittance, and optionally local minimum impedance values, but at higher frequencies and other parameters to distinguish the region to be excluded. Furthermore, the controller 210 may determine the frequency range corresponding to the detected minimum impedance value when dips in impedance due to parasitic losses in the battery buck are likely to correspond to a lower frequency range.

[0062] In addition, an impedance curve plot 714 obtained from the pack, where energy jumps between cells in the pack, can be used by the controller 210 to indicate or identify the pack configuration. For example, a first battery pack configuration including cells connected in series may have a different impedance plot than a second battery pack configuration including cells connected in parallel. The total number or orientation difference of different cells detectable between packs can also be used. Thus, the controller 210 can acquire an impedance plot for the battery pack (in addition to plots of other aspects of the battery pack such as conductance and / or susceptance) and compare the acquired plot with a database of impedance plots. The database of impedance plots can correlate each plot with a specific battery pack configuration or battery cell type, and thus, by comparing the acquired impedance plot with the stored plots, the controller 210 can determine or estimate the configuration or cell type of the battery pack during charging. The controller 210 can then further adjust or shape the charging pulse based on the estimated battery pack configuration.

[0063] Regardless of the method for determining the upper limit impedance value 720 for the range described above, the circuit controller 210 operates at the frequency f corresponding to the upper limit impedance value 720 in operation 806. RMax 710 can be determined. As mentioned above, the impedance at the battery cell electrodes may change based on the frequency of the charging signal applied to the electrodes. Therefore, the frequency f RMax 710 can accommodate a selectable upper impedance value of 720 for the allowable range. The circuit controller 210 corresponds to the frequency f of the selectable upper impedance value of 720. RMax 710 can be determined.

[0064] In operation 808, the circuit controller 210 may further select a lower impedance value 718 for the corresponding range of acceptable impedance values ​​based on the lowest impedance value 712 obtained with respect to the battery. Similar to the upper impedance value 720 for this range, the lower impedance value 718 may be selected or determined based on the acceptable impedance value 716 and the frequency f at which the lowest impedance value 712 occurs. Min lower frequencies f than 711 RMin It can be located at 708. In other words, the circuit controller 210 plots the impedance value curve 714 at the frequency f where the lowest impedance value 712 occurs. Min The lower impedance value 718 for the acceptable impedance range can be determined or selected by tracing from 711 to the left (decreasing frequency) until an acceptable impedance value 716 is encountered. Thus, the upper impedance value 720 and the lower impedance value 718 are equal in some cases (for example, the acceptable impedance value 716 for this range), for example, at the frequency f of the lowest impedance of the charging signal. Min 711 can occur at different frequencies above and below it. In another implementation, the lower impedance value 718 for the impedance value range can be the difference from the lowest impedance value 712, as well as the upper impedance value 720 for this range. Regardless of how the upper impedance value 720 is diametered, the circuit controller 210 operates 810 at the corresponding frequency f of the lower impedance value. RMin 708 can be determined. Generally, the corresponding frequency f RMin 708 corresponds to the frequency f of the lowest impedance value 712. Min It is a frequency lower than 711. In some examples, the acceptable range or set of harmonics for generating a charging pulse is the frequency f in this range. RMax 710 and frequency f RMin It falls within the range of 708, and the frequency f Min It is possible to base this on a frequency range that also includes 711.

[0065] In yet another embodiment, the circuit controller 210 may not determine one or both of the upper impedance value 720 or the lower impedance value 718. Instead, the circuit controller 210 determines the frequency f for the impedance value range. RMax 710 and frequency f RMin 708 can be selected (for example, by referencing in a table). In some cases, either or both of the upper and lower frequency limits are the lowest impedance frequency f that can be measured or retrieved from memory. Min Based on 711, it is possible to generate historical models and extrapolate from past measurements. The lowest impedance frequency f Min Based on 711, frequency f RMax 710 and / or frequency f RMin By selecting 708, the circuit controller 210 can control the frequency range or bandwidth for the charging signal. Furthermore, the frequency range can be selected based on the measured impedance value of the battery cell or the measurement history of the battery cell or other battery cells, so as to ensure that the corresponding impedance value within it remains below one (or more) acceptable threshold values ​​716 for charging the battery cell.

[0066] In operation 812, the circuit controller 210 controls the frequency f RMax 710 and frequency f RMin Amplitude values ​​associated with multiple frequencies within the frequency range defined by 708 can be obtained. In one implementation, the amplitude associated with frequencies within this range may be proportional to the impedance measured or estimated at those frequencies. For example, frequency f RMax The amplitude obtained for inclusion within the charging pulse at 710 can be proportional to the real impedance value 720 at that frequency. Similarly, frequency f MinThe amplitude obtained for inclusion within the charging pulse at 711 can also be proportional to the real impedance value 712 at that frequency. Therefore, each frequency mentioned above can have a corresponding amplitude corresponding to the impedance value 714 at that frequency. However, it should be noted that the impedance of each harmonic may not necessarily be independent of the amplitude of the other harmonics of the waveform.

[0067] In operation 814, the circuit controller 210 can control the pulse control signal and PWM signal of the charging circuit 400 to generate shaped charging pulses for the battery cell 404. As described above, the circuit 400 in Figure 4 can be used to generate charging signal pulses for the battery cell 404 under charge. In particular, the filter circuit 406 and / or input shaping circuit 420 can be controlled to shape the power from the upper rail 442 into a series of charging pulses including one or more frequencies or harmonics corresponding to the frequency range determined above. In one example, the filter circuit 406 has a frequency f RMax 710 or frequency f RMin It can be controlled to generate a leading edge corresponding to 708. Furthermore, the duration of the pulse control signal 416 can determine the harmonic range for the charging pulse, such that a longer duration of the pulse control signal 416 can correspond to a wider charging pulse (or wider charging pulse bandwidth). Furthermore, the input shaping circuit 420 can be controlled through the PWM signal 426 to change the amplitude of the charging pulse at a specific instance or harmonic of this signal. In this way, the circuit controller 210 controls the frequency f RMax 710 and frequency f RMin One or more inputs can be provided to the circuit 400 to shape the charging pulses to include multiple harmonics based on a determined frequency range defined by 708. By method 800 in Figure 8, the circuit controller 210 can generate a series of charging pulses shaped to provide an optimal amount of charge to the battery 404 while suppressing or reducing the impedance at the battery cell electrodes to the lowest possible level.

[0068] The determined frequency range and the charging signal generated therefrom can be used according to method 500 in Figure 5. In particular, the circuit controller 210 can generate a charging signal from a frequency range based on a first set of measured impedance values ​​to begin charging the battery cell. Through the iterative process discussed with respect to Figure 5, a second set of measured impedance values ​​can be obtained during a battery cell recharging session. A second frequency range can then be determined based on the second set of measured impedance values, and the charging signal can be adjusted accordingly. In this way, an iterative process can be performed that includes recalculating the range of frequencies or harmonics included in the charging signal, with the aim of adjusting or modifying the pulses of the charging signal during battery cell recharging based on additional measurements of the impedance values ​​of the battery cell.

[0069] Figure 9A is a signal diagram 902 of a series of frequency-tuned charging pulses 902 generated from a battery charging circuit according to one embodiment. In one example, the circuit 400 can generate pulses 914, 916 based on a controller 210. The signal diagram 902 shows the input voltage 904 or, in the case of a current-controlled hardware circuit, the input current for the charging signal pulses 914, 916 over time 906. As is clear, each pulse 914, 916 is asymmetrical, shaped such that the leading edge 912 is distinctly different from the trailing edge 910. The pulses 914, 916 (e.g., leading edge and / or body) can, in one example, be defined by a combination of harmonics corresponding to or related to the lowest impedance value found at the battery cell electrodes. In particular, the charging signal pulses 914, 916 may include a leading edge portion 912 corresponding to a selected frequency with respect to the lowest impedance value with respect to the battery cell. For example, the shape of the leading edge 912 of pulse 914 is identified by the control circuit 210 as the frequency at the lowest real impedance value in the battery cell, which is a harmonic f. Min It is possible to accommodate 332. In one example, the shape of the leading edge 912 can be based on the leading edge of the corresponding sine wave at the lowest impedance frequency. In another example, the shape of the leading edge 912 of pulse 914 can be based on the harmonic f RMax710 or the harmonic f RMin It is possible to accommodate 708. The step of identifying the lowest impedance frequency can be based, in particular, on one (or more) measurements, either alone or in combination with the battery characteristics. Regardless of the selected frequency, the leading edge 912 of pulse 914 can be shaped to be the same as the leading edge of a portion of the sinusoidal charging signal at harmonics that suppress or reduce the impedance found in the battery cell to the lowest possible level for more efficient application of the power recharge signal.

[0070] The circuit controller 210 can control one or more of the filter circuits 406 discussed above to generate the leading edge 912 of the pulse 914 with a selected harmonic. For example, the shape of the leading edge 912 of the pulse 914 can correlate with the inductance value of the first inductor 410. In particular, the first inductor 410 resists abrupt current flow such that the current through it starts slowly and increases over time. The resistance to current flow through the inductor depends on the inductance value of the first inductor 410. Therefore, to shape the leading edge 912 of the pulse 914 of the charging signal, the circuit controller 210 can activate the first transistor 412 to start current flowing through the inductor 410 to the battery cell 404 (through the pulse control signal 416). The current flow can start slowly and increase over time, and since the voltage of the charging signal is related to the current of the charging signal, the voltage can follow the current and form the leading edge 912 of the pulse 914 as shown in Figure 9A. Generally, the rate of increase in current flow through the first inductor 410 can give the shape of the leading edge 912 to the charging signal pulses 914, 916 based on the inductance value of the inductor. Thus, the harmonics of the leading edge 912 can be associated with the inductance value of the first inductor 410. To fit the target harmonic to the leading edge 912, the circuit controller 210 can select from a plurality of filter circuits 406, 418 or the first inductor to generate the slope of the leading edge 912 corresponding to the determined harmonic with the lowest real impedance. Furthermore, the resistance of the first inductor 410 to abrupt current increases prevents a sharp leading edge in the charging signal pulses, which can reduce high-frequency harmonics that may occur in the battery cell 404 when a square wave input is applied.

[0071] Through the activation of the first transistor 412 via the pulse control signal 416, the circuit controller 210 can generate the leading edge 912 of a pulse 914 with a selected harmonic when current flows through the first inductor 410. At any point in the pulse 914, the amplitude of the pulse can reach the upper limit voltage or stray voltage of the power rail 442 corresponding to the constant voltage 908 at the top of the pulse 914. The duration of the pulse 914 can be controlled by the circuit controller 210 by maintaining the energized state of the first transistor 412 so that power is supplied to the battery cell 404 through the first inductor 410 and the first transistor 412. In this way, the pulse control signal 416 can control the duration or width of the pulse 914 of the charging signal.

[0072] In some cases, the circuit 400 can be controlled to include a sharp trailing edge 910 of the pulse 914. The circuit controller 210 can generate the sharp trailing edge 910 of the pulse by stopping the first transistor 412 and disconnecting the battery cell 404 from the power rail 442. In particular, the circuit controller 210 can stop the pulse control signal 416 and cut off the power supply to the first transistor 412. As described above, the current flowing through the first inductor 410 can be returned to the power rail 442 through the flyback diode 414 when the first transistor 412 is cut off. In this way, the control of the first transistor 412 can cause the sharp trailing edge 910 of the pulse 914. Furthermore, while a steep trailing edge 910 may generally correspond to higher harmonic components, such harmonics may not increase harmful impedance in the battery cell 404 because the amplitude of the current and voltage across the battery 404 approaches or equals zero (or zero overvoltage in the case of voltage) following the steep trailing edge 910. This separation between higher harmonics and harmful impedance remains in effect even when the voltage amplitude is temporarily reduced below the battery's stray voltage (e.g., the battery voltage when no charging current is being received) to shorten the time required for the charging current to reach zero, as will be explained in more detail below with reference to Figure 12B. By controlling the filter circuit 406, it is possible to generate a shaped charging pulse 418 that includes a sinusoidal leading edge 912 at the harmonic associated with the lowest impedance value of the battery cell 404, a duration at the upper amplitude 908, and a steep trailing edge 910, providing a sufficient amount of charge to the battery cell 404 while maintaining low impedance at the battery electrodes.

[0073] Generally, the circuit 400 can be controlled to generate and shape pulses of a charging signal. For example, Figure 9B is a signal diagram 922 of a series of second shaped charging pulses 924, 932 generated from a battery charging circuit 400 according to one embodiment. In this example, the leading edge 928 of each pulse 924, 932 can be the same as the leading edge 912 discussed above with respect to Figure 9A. In particular, the leading edge 912 of the charging pulses 924, 932 can be generated by controlling one or more of the filter circuits 406 discussed above. However, in this example, rather than a pulse having a flat voltage level 908 over the duration of the pulse after the shaped leading edge 928, the circuit controller 210 can control one or more of the input shaping circuits 420, 428 of the charging circuit 400 to further shape pulse 924. In the illustrated example, the portion 926 of the pulse 924 following the leading edge 928 may include a voltage (or current) that uniformly decreases to a steep trailing edge 930. While the drop level (or gradient) 926 is shown linearly, it does not have to be, and the pulse 924 can be shaped to include many features. In one embodiment, the control circuit 210 may provide a PWM signal 426 to a second transistor 422 of the input shaping circuit 420. As described above, the PWM signal 426 may be a high-frequency switching signal that alternates the second transistor 422 between an energized (or "on") state and an unenergized (or "off") state. The abrupt alternation of the second transistor 422 can cause current from the pulse 924 to flow through the second inductor 424. This draw-up of current from the pulse 924 can cause a downward gradient portion 926 when the current is removed. Generally, the load cycle of the PWM signal 426 can control the amount of current drawn from the pulse 924, and the circuit controller 210 can be configured to generate the gradient 926 of the pulse 924. Furthermore, as described above, the off portion of the PWM signal 426 can close the transistor 422 quickly enough so that most or none of the energy signal drawn from the charging pulse is not transmitted to ground through the connector 446.Alternatively, the absorbed energy can be transmitted to the upper rail 442 through the flyback diode 430 and stored in the energy storage capacitor 432 for reuse by the charging circuit 400.

[0074] At the end of the charging pulse 924, the circuit 400 can be further controlled to define a steep trailing edge 930, as discussed above with respect to Figure 9A. In particular, the circuit controller 210 can generate a steep trailing edge 910 of the pulse by stopping the first transistor 412 and disconnecting the battery cell 404 from the power rail 442. In particular, the circuit controller 210 can stop the pulse control signal 416 to de-energize the first transistor 412. In yet another example, the input shaping circuit 420 can be activated by the PWM signal 426 to draw current at the trailing edge 930 and further shape the trailing edge of the pulse 924. It should be acknowledged that the charging pulses 924, 932 shown in Figure 9B are merely examples of shaped charging signals that can be generated by controlling the charging circuit 400. In particular, the circuit controller 210 can control the filter circuit 406 and / or the input shaping circuit 420 to generate charging pulses of various shapes as needed. In this way, other charging signal shapes, such as those shown in Figures 3A, 7B, and / or 9A, can be generated from circuit 400.

[0075] While the real impedance values ​​at battery electrodes were discussed above, the reactance or imaginary part of the impedance at battery electrodes can be considered when shaping the charging signal. Other aspects such as admittance and / or susceptance values ​​can be considered. In particular, Figure 10A is a signal diagram showing a sinusoidal voltage signal 1004 used to generate a charging current 1006 for recharging a battery cell. Generally, the charging current 1006 measured at a battery cell can have the same shape as the applied voltage signal 1004. However, due to the impedance of the battery, the charging current 1006 applied to the battery may have a smaller amplitude and may experience a time delay relative to the voltage signal 1004. The qualitative amplitude difference between the voltage signal 1004 and the current 1006 at the battery is given by the real impedance ZR = (dV / dI) or (ΔV / ΔI). R It is intended to show a measurement of 1008. One or more of the methods and circuits discussed above take this real component into account when shaping the pulse of the charge signal for recharging the battery. The time delay between the application of the voltage signal 1004 and the current 1006 at the battery is Z. IIllustrated as 10¹⁰, this time delay is due to the reactance or imaginary component of the battery impedance. Similar to the real component of impedance, the reactance 10¹⁰ portion of impedance can also cause inefficiencies when applying a charging signal to the battery during a charging session. For example, generally, the duration of a charging waveform is measured from the point when either the charging voltage or charging current begins to recharge the battery, and ends when the voltage returns to zero overvoltage and settles (the voltage at both terminals matches the battery's stray voltage) and there is no charging current into the battery (zero amperes). However, charging systems that ignore the reactance portion of impedance in the battery cell may assume that the voltage and the resulting charging current waveform into the battery start and stop simultaneously. However, considering the reactance portion of impedance reveals a time delay that causes a longer charging period per pulse due to the capacitively or inductively induced delay between the voltage and current of the charging signal in the battery cell's voltage and current waveforms. Furthermore, this can lead to a decrease in the average current over the charging duration of a pulse, resulting in high inefficiency of the charging pulse in the battery cell. Furthermore, depending on the reactance level, the reactance component may convert energy into thermoformation rather than chemical energy stored within the battery. Reactance is problematic, as it can generate heat in conductive paths (cables, wires, and circuit board traces, etc.) as well as within the cell itself. High levels of reactance can contribute to uneven electrochemical activity across electrode regions and may worsen resistance drops across current collectors, electroactive materials, and other components within the battery cell.

[0076] To address this potential inefficiency in applying a charge signal to a battery cell, the system can generate a charge signal having pulses corresponding to the determined or estimated reactance component of the impedance in the battery cell. In particular, the pulse shape and overall duration of the pulses of the charge signal for recharging the battery cell can be adjusted to correspond to the imaginary component of the impedance. For example, see Figure 10B, which shows graph 1022 of various components of the impedance 1024 in the battery against a frequency 1026 of the charge signal applied to the battery. In particular, graph 1022 includes plots of real impedance values ​​1028, imaginary impedance values ​​1032, and calculated absolute impedance values ​​1030. The method discussed herein corresponds to the lowest real impedance value at frequency f Zr 1034 can be determined and used to generate a charging signal having pulses containing harmonics at the mentioned frequency or harmonics in a certain frequency range higher and / or lower. However, as shown in Graph 1022, the frequency f corresponding to the lowest real impedance value is Zr 1034 can be associated with the relatively high imaginary impedance value 1032 at the battery electrodes. Therefore, considering only the real impedance may not lead to an optimal charging scheme, as it does not take into account the imaginary impedance and its effect on charging efficiency. Accordingly, some implementations of the circuits and methods described herein can be optimized by considering both imaginary and real impedances to varying degrees, for example, by understanding the frequencies of both impedance components in the battery cell, at the starting frequency when determining the pulse shape and the duration of the entire charging signal to which such pulses are applied. Further implementations may use admittance and / or susceptance values ​​calculated from the measured real impedance and / or measured imaginary impedance in the battery cell.

[0077] For example, the circuit controller 210 can calculate or otherwise obtain a combination of real and imaginary impedance values ​​to select the frequency or harmonic when generating the charging signal pulse. One such combination may include calculating the absolute values ​​of the real and imaginary impedance values. A plot of the absolute impedance values ​​1030 is illustrated in graph 1022 of Figure 10B. The circuit controller 210 can calculate or determine other combinations of both impedance components in the battery and use them to shape the charging signal pulse. For example, one or both of the real and imaginary impedance values ​​can be weighted unevenly (e.g., 20% weight applied to the real impedance value and 80% weight applied to the imaginary impedance value) or evenly and can be used to determine various aspects of the charging signal pulse, such as the leading edge or width of the charging pulse. Similarly, the circuit controller 210 can obtain the lowest absolute impedance value and the corresponding frequency (frequency f in graph 1022). ZMod The frequency f (shown as 1036) can be determined. As can be seen in graph 1022, the frequency f ZMod By generating a charging pulse with 1036 harmonics, higher frequencies than other frequencies, especially f, are produced. Zr While this may introduce a higher real impedance into the battery compared to other systems, the imaginary impedance component can be minimized or mitigated. Therefore, by considering both impedance components in the battery cell (real impedance 1028 and imaginary impedance 1032), a more efficient charging signal can be generated. Considering both impedance components in the battery cell can be particularly advantageous in systems with multiple cells where the impedances are added together by the connections between these cells.

[0078] In some cases, the circuit controller 210 controls the frequency f corresponding to the lowest real impedance value. Zr 1034 or frequency f corresponding to the minimum absolute impedance calculation ZModA frequency different from any of 1036 can be selected for the charging signal. In other words, the circuit controller 210 selects a frequency for the charging signal to determine the harmonics of the charging signal, which is frequency f. Zr 1034 and frequency f ZMod The real impedance value and the imaginary impedance value can be balanced so that they can be placed between 1036.

[0079] In one particular implementation, separate portions of the charging signal pulse can be shaped by the circuit controller 210 based on more than one impedance measurement. For example, Figure 11 is a signal diagram of a shaped pulse 1108 of a battery cell charging signal 1102 generated from a battery recharging circuit according to one embodiment and associated with two or more frequencies. Similar to the power signal pulse discussed above with reference to Figure 9A, pulse 1108 may include a leading edge portion 1110 configured as a harmonic associated with the lowest real impedance value. The shape of the leading edge portion 1110 of pulse 1108 is such that the harmonic f Zr It is possible to correspond to 1034. However, the second part 1112 of pulse 1108 has a frequency f Zr It may include harmonics based on different frequencies than 1034. For example, the leading portion 1110 and the second portion 112 together correspond to the first harmonic f of the lowest absolute impedance calculation 1030. ZMod It can include 1036. The harmonic f corresponding to the minimum absolute impedance calculation. ZMod By applying 1036, the duration of the second portion 1112 of pulse 1108 can be determined such that it reduces the imaginary impedance at the battery electrodes from the application of the power recharge signal. By determining and applying harmonics based not only on the real impedance component but also on the imaginary impedance component at the battery, a more efficient power recharge signal can be used to charge the battery cells.

[0080] Further aspects of the charging signal pulses can be controlled by circuit 400. In particular, efficiency advantages for charging battery cells can be achieved by controlling the trailing edge of the charging signal pulses. Figures 12A and 12B are plots of the applied / measured voltage 1208 across the battery cell and the measured charging current 1210 in the battery cell against time 1206 according to one embodiment. As discussed above, the charging signal may include a steep trailing edge to remove the charging signal 1202 to the battery cell. However, as can be seen in the plot of Figure 12A, when the voltage applied to the battery is set to zero, the current I does not drop to zero immediately but has some delay before reaching zero. However, the time between pulses can be set so that the next pulse does not start until the current reaches zero (the cell is polarized). Thus, in one example, circuit 400 can be controlled to wait until the current in the battery cell 404 reaches zero before the next pulse of the charging signal can start in order to prevent other inefficient charging from starting to polarize the cell before potential damage or complete polarization of the battery cell occurs. Since charging can only occur during pulses, shortening or minimizing the time between pulses is expected to shorten the total charging time, assuming all other conditions are equal. In a variation of the voltage control of circuit 400, the current component 1210 of the charging signal may lag behind the voltage component 1208. More specifically, as shown in Figure 12A, the current 1210 in the battery may consume some time to return to zero after the voltage 1208 to the battery has been removed. This delay in the current returning to zero in the battery may add additional inefficiency to the charging pulse. Therefore, in some implementations, the voltage 1208 of the charging signal can be controlled to drive a voltage lower than the transient voltage corresponding to the zero current, represented as line 1206 in plot 1222 of Figure 12B, as shown in plot 1222 of Figure 12B. Generally, the transient voltage 1206 is the charging signal voltage, which can be similar to the stray voltage of the battery cell when the current flowing into the battery is reversed. In particular, the period following the trailing edge 1212 of the pulse (period T) TBy driving a voltage 1208 lower than the transient voltage 1206 over a period of time T (represented as 1216), the current 1210 can be driven down to zero amperes at a faster rate compared to a pulse without a blip. The voltage 1208 of the voltage-controlled charging circuit 400 is controlled to be lower than the transient voltage corresponding to zero current for a duration T. T 1216 can be determined or set by the circuit controller 210 to minimize the time it takes for the current 1210 in the battery cell 404 to return to zero amperes. For example, the voltage dip can be controlled so that it does not fall below the recommended minimum cell voltage for the battery cell in order to protect the battery cell electrodes from degradation. The magnitude of the voltage dip can be controlled to be a percentage of either the transient voltage or the charging pulse amplitude. Furthermore, the return of the voltage to the transient voltage can be controlled at a rate that keeps the current at zero amperes as long as the amount of charge in the battery cell remains constant and in equilibrium. Once the current 1210 returns to zero amperes over a certain rest period, another charging pulse 1202 can be applied to the battery cell 404. Thus, reducing the time required for the current 1210 in the battery cell 404 to return to zero can increase the rate at which charging pulses can be applied to charge the battery cell.

[0081] Although the above discussion was generally presented as a power control circuit, it must be acknowledged that the charging circuit 400 can be voltage-controlled, current-controlled, or each of these can be used in various situations. Both methods are controlled by measuring the voltage drop across the battery cell 404 and by measuring the current through a current-sensing resistor connected in series with the battery cell 404. The main difference between these controlled schemes is based on whether the current-sensing hardware (such as a current-sensing resistor) is external or internal to the power supply circuit (such as the power amplifier of the power supply circuit 402), and whether the voltage drop across the battery cell 404 or the current-sensing resistor is processed first. In a voltage-controlled power supply, the main voltage can be measured across the battery cell 404 so that the current in the battery cell 404 can be calculated using Ohm's law, etc., while the corresponding voltage drop across an external current-sensing resistor can be measured secondarily. This makes it possible to precisely control the voltage of the charging signal while calculating the current by first measuring the voltage across the battery cell 404 and then continuing to calculate the current in the battery cell.

[0082] A voltage-controlled charging circuit can be controlled to provide a charging signal having components shown in Figure 12B in some implementations. In particular, the voltage of the charging signal 1202 can be controlled to provide a flat voltage continuing over the rest of the pulse body following the sinusoidal leading edge 1214 described above. A voltage-controlled charging signal can bring advantages to the charging pulse as described above. The trailing edge 1212 can be provided from a voltage control circuit 400, which includes a portion 1216 driven so that the voltage in the battery cell 404 is lower than the transient voltage corresponding to zero current. As also shown in Figure 12B, the current 1210 in the battery cell 404 may lag behind the controlled voltage 1208, and the calculation of the current following the control of voltage 1208 is illustrated. By controlling voltage signal 1208, the current 1210 can return to zero amperes before additional charging pulses are provided to the battery cell 404 in a similar scheme. An additional advantage of the voltage control circuit 400 is that it provides precise control to ensure that the voltage does not exceed the thermodynamic threshold of the battery cell 404 in order to prevent the deterioration of the battery cell 404's properties, for example, by remaining below the voltage at which the electrolyte of the battery cell 404 begins to decompose.

[0083] The circuits and methods discussed herein can be implemented using a current-controlled power supply. In the current-controlled power supply of circuit 400, a pre-calibrated sensing resistor in the power supply circuit can provide a primary measurement such that the current flowing across the resistor can depend on the current flowing through the battery cell 404. Thus, by knowing the charging current precisely, it is possible to precisely control the charging current to the battery cell 404 without knowing the voltage drop across the battery cell. In this implementation, the current into the battery cell 404 (measured by the current-sensing resistor) may be known in advance (by the pre-calibrated voltage drop across the sensing resistor), and the voltage across the battery cell 404 from which this applied current is obtained is measured. Figure 13 is a plot of the measured current 1302 across the current-sensing resistor and the voltage 1310 in the battery cell against time 1306 in response to a charging signal 1304 applied to a battery cell according to one embodiment. As shown in plot 1302, the current to the battery cell 404 can be controlled to generate a pulse similar to that described above, having a sinusoidal leading edge 1314 roughly corresponding to the lowest impedance value in the battery cell 404, followed by a steady current. The trailing edge 1312 can be provided from a current-controlled circuit 400, which includes a portion 1316 driven so that the current is lower than zero amperes, corresponding to a stable transient voltage in the battery cell 404. As also shown in Figure 13, the voltage response 1310 in the battery cell 404 may lag behind the controlled current 1308, illustrating the voltage behavior as a feedback response rather than a primary control factor.

[0084] In applications where simple components can be used or where the process is constrained by existing power hardware on the device under charge, current control can be the default mechanism. Alternatively, in implementations where both the controller response time and the battery transient response are fast, voltage control and current control methods may exhibit similar behavior. However, when the frequency increases and / or when the battery exhibits higher reactance levels, the behavior may diverge between the two methods, and practical control requirements can be considered.

[0085] The implementation discussed above includes a step of measuring or otherwise acquiring the real and / or imaginary impedance of the battery cell 204 in order to determine the frequency components of at least a portion of the pulses of the charging signal. The impedance values ​​of the battery cell 204 can be acquired by various methods or techniques. In one implementation, the impedance in the battery cell 204 can be measured or estimated in real time as the charging pulse is applied to the battery cell. For example, the amplitude and time components of the voltage and current waveforms of the charging signal in the battery cell 204 can be measured and / or estimated. The real, imaginary, or approximate impedance in the battery cell 204 can be determined or estimated using the difference between the measured amplitude and time components of the voltage and current waveforms. For example, the real and imaginary impedance values ​​can be determined from the leading edge of the charging pulse by the leading edge containing a single known harmonic, and the difference between the amplitude of the voltage waveform and the amplitude of the current waveform can be acquired at the constant minimum and maximum values ​​of the edge. Similarly, the impedance characteristics can be approximated from the amplitude measurements of the voltage and current waveforms at the trailing edge of the charging pulse. In further implementations, various measurements of the voltage and current waveforms of the charging signal can be adjusted based on weighted values ​​applied to these measurements. Generally, certain aspects of the voltage and current waveforms of the charging signal can be determined or measured to determine or estimate the impedance in the battery cell 204. In another implementation, hundreds or thousands of measurements of the voltage or current waveform can be obtained and analyzed by a digital processing system. Generally, higher fidelity and / or a larger number of waveform measurements of these waveforms can provide a more accurate analysis of the impedance of the waveform applied to the battery cell 204 in order to determine the shape of the pulses of the charging signal, to more accurately determine the harmonic components of the charging signal that produce the lowest impedance value, or to more accurately determine other aspects of the effect of these waveforms on the battery cell 204.

[0086] Figure 14 is a block diagram showing an example 1400 of a computer device or computer system that can be used to implement the network embodiments disclosed above. In particular, the computer device in Figure 14 is an embodiment of a circuit controller 210 that performs one or more of the operations described above. The computer system (system) includes one or more processors 1402-1406. The processors 1402-1406 may include one or more internal-level caches (not shown) and a bus controller or bus interface unit for inducing interaction with a processor bus 1412. The processor bus 1412, also known as a host bus or front-side bus, can be used to connect the processors 1402-1406 to a system interface 1414. The system interface 1414 can be connected to the processor bus 1412 to interface other components of the system 1400 with the processor bus 1412. For example, the system interface 1414 may include a memory controller 1418 for interface main memory 1416 with the processor bus 1412. The main memory 1416 generally includes one or more memory cards and control circuits (not shown). The system interface 1414 may further include an input / output (I / O) interface 1420 for interface one or more I / O bridges or I / O devices with the processor bus 1412. One or more I / O controllers and / or I / O devices may be connected to the I / O bus 1426, such as an I / O controller 1428 and an I / O device 1430 as shown.

[0087] The I / O device 1430 may further include an input device (not shown) such as an alphanumeric input device including alphanumeric and other keys for communicating information and / or command selections to processors 1402-1406. Another type of user input device may include a cursor controller such as a mouse, trackball, or cursor directional keys for communicating directional information and command selections to processors 1402-1406 and for controlling cursor movement on a display device.

[0088] System 1400 may include a dynamic storage device called main memory 1416, random access memory (RAM), or other computer-readable device coupled to the processor bus 1412 for storing information and instructions executed by processors 1402-1406. Main memory 1416 can be used to store temporary variables or other intermediate information during the execution of instructions by processors 1402-1406. System 1400 may also include read-only memory (ROM) and / or other static storage devices coupled to the processor bus 1412 for storing static information and instructions for processors 1402-1406. The system shown in Figure 14 is just one possible example of a computer system that can use or be configured in accordance with aspects of the disclosure of the present invention.

[0089] In one embodiment, the above-described technology can be implemented by a computer system 1400 in response to a processor 1404 executing one or more sequences of one or more instructions contained in main memory 1416. These instructions can be read into main memory 1416 from another machine-readable medium, such as a storage device. The execution of the instruction sequence contained in main memory 1416 can cause processors 1402-1406 to perform the processes described herein. In alternative embodiments, circuits can be used instead of or in combination with software instructions. Thus, embodiments of the disclosure of the present invention can include both hardware and software components.

[0090] A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer) (e.g., software, processing applications). Such a medium may, but is not limited to, be a non-volatile medium or a volatile medium. Non-volatile mediums include optical disks or magnetic disks. Volatile mediums include dynamic memory such as main memory 1416. Common forms of machine-readable mediums may, but are not limited to, magnetic storage media (e.g., floppy disks), optical storage media (e.g., CD-ROMs), magneto-optical storage media, read-only memory (ROM), random-access memory (RAM), erasable programmable memory (e.g., EPROMs and EEPROMs), flash memory, or other types of media suitable for storing electronic instructions.

[0091] Embodiments of the disclosure of the present invention comprise various steps described herein. These steps can be carried out by hardware components or by machine-executable instructions, which can be used to cause a general-purpose or dedicated processor programmed thereby to carry out these steps. Alternatively, these steps can be carried out by a combination of hardware, software, and / or firmware.

[0092] For the purpose of clarifying the explanation, in some cases, various embodiments may be provided as individual functional blocks, which include steps or routines in a manner that are implemented in a device, device components, or software, or a combination of hardware and software.

[0093] The claim language that lists "at least one of" means at least one of the elements of the set, indicating that one or more components of the set satisfy the claim. For example, the claim language that lists "at least one of A and B" means A, B, or A and B.

[0094] In some embodiments, computer-readable storage devices, media, and memory may include cable or wireless signals, such as bitstreams. However, non-transient computer-readable storage media, as referred to, explicitly exclude media that are essentially energy, carrier signals, electromagnetic waves, and signals.

[0095] The methods described above can be implemented using computer-executable instructions stored or available from other computer-readable media. Such instructions may include, for example, instructions and data that cause a general-purpose computer, a dedicated computer, or a dedicated processing device to perform certain functions or sets of functions, or to configure such general-purpose computers, dedicated computers, or dedicated processing devices to perform such functions. Some of the computer resources used may be accessible over a network. Computer-executable instructions may be, for example, binaries, instructions in intermediate formats, such as assembly language, firmware, or source code. Examples of computer-readable media that can be used to store instructions, information used, and / or information generated within the methods described above include magnetic disks or optical disks, flash memory, USB devices with non-volatile memory, network-attached storage devices, and the like.

[0096] Devices implementing the methods in accordance with the above disclosures may include hardware, firmware, and / or software, and may take any of a variety of form factors. Typical examples of such form factors include laptops, smartphones, small form factor personal computers, personal digital assistants, rack-mount devices, standalone devices, and so on. The functions described herein may be implemented within peripheral devices or add-in cards. Such functions may, as yet another example, be implemented between various chips on a circuit board or between various processes performed within a single device.

[0097] Instructions, a medium for transmitting such instructions, computer resources for executing these instructions, and other structures for supporting such computer resources are means for providing the functions described in the above disclosure.

[0098] Various embodiments of the disclosure of the present invention have been discussed in detail above. While specific implementations have been discussed, it should be acknowledged that this discussion is for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from the spirit and scope of the disclosure of the present invention. Similarly, various combinations of various aspects of the various embodiments define multiple different embodiments. Therefore, the above description and drawings are illustrative and should not be construed as limiting. Many specific details have been described to provide a complete understanding of the disclosure of the present invention. However, in certain cases, known or prior art details have been omitted to avoid obscuring the description. Any embodiment or reference to an embodiment in the disclosure of the present invention may refer to the same embodiment or any of the embodiments, and such reference means at least one of the embodiments.

[0099] A reference to “one embodiment” or “embodiment” means that a particular feature, structure, or characteristic described in relation to that embodiment is included in at least one embodiment of the disclosure of the present invention. The phrase “in one embodiment” appearing in various parts of this specification does not necessarily refer to the same embodiment, nor do they refer to separate or alternative embodiments that exclude each other from other embodiments. Furthermore, various features are described that are shown in some embodiments but not in others.

[0100] The terms used herein generally have the ordinary meaning in the art within the relevant scope of the disclosure and in the specific context in which each term is used. Substitute words and synonyms may be used for one or more of the terms discussed herein, and no special significance should be placed on whether or not a term is elaborated upon or discussed herein. In some cases, synonyms are provided for certain terms. The enumeration of one or more synonyms does not preclude the use of other synonyms. The use of examples anywhere in this specification, including examples of any of the terms discussed herein, is illustrative only and is not intended to further limit the scope and meaning of the disclosure or any exemplary term. Similarly, the disclosure is not limited to the various embodiments provided herein.

[0101] The embodiments of the disclosure of this invention are not intended to limit the scope of the disclosure, but rather provide examples of apparatus, devices, methods, and related results. These examples may use titles or subtitles for the convenience of the reader, but it should be noted that they should not, of course, limit the scope of the disclosure of this invention. Unless otherwise specified, the technical and scientific terms used herein have meanings commonly understood by those skilled in the art to which the disclosure of this invention belongs. In case of incompatibility, this specification, including its definitions, shall prevail.

[0102] This specification provides additional features and advantages of the disclosure of the present invention, some of which are evident from this specification or can be acquired through the practice of the principles discussed herein. The features and advantages of the disclosure of the present invention are brought about and can be acquired, in particular, by using the apparatus and combinations thereof indicated in the claims. These and other features of the disclosure of the present invention are more fully evident from the above description and the claims or can be acquired through the practice of the principles described herein.

[0103] Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the invention. For example, while the embodiments described above refer to certain features, the scope of the invention also includes embodiments having various combinations of features and embodiments that do not include all of the features described. Accordingly, the scope of the invention is intended to encompass all such substitutions, modifications, and variations, along with all their equivalents. [Explanation of Symbols]

[0104] Circuit for recharging 200 battery cells 202 Power supply 204 battery cells 206 Charging signal shaping circuit 208 Impedance Measurement Circuit

Claims

1. A method for charging an electrochemical device, The process involves accessing a harmonic profile that explains the relationship between the harmonic frequencies of the charging signal and the impedance of the electrochemical device, A step of controlling the energy flux at the electrodes of the electrochemical device, wherein the energy flux includes repetitive pulses, each pulse including a leading edge portion that is controllably shaped to correspond to the shape of a sine wave of a harmonic frequency, and the leading edge portion is followed by a steady-state charging current. A method characterized by comprising:

2. The method according to claim 1, characterized in that the harmonic frequency is associated with the lowest real impedance value of the electrochemical device.

3. The method according to claim 1, characterized in that the harmonic frequency is associated with the lowest imaginary impedance value of the electrochemical device.

4. The method according to claim 1, characterized in that the harmonic frequencies are associated with a combination of real impedance values ​​and imaginary impedance values ​​of the electrochemical device.

5. The method according to claim 4, characterized in that the harmonic frequencies are associated with the absolute value combination of the real impedance value and the imaginary impedance value of the electrochemical device.

6. The method according to 4, characterized in that the harmonic frequency is associated with a combination of the real impedance value adjusted by a first weighting value and the imaginary impedance value adjusted by a second weighting value.

7. The aforementioned harmonic frequencies are related to the lowest impedance value of the electrochemical device. The step of determining the change in the minimum impedance value, A step of controlling the energy flux at the electrodes of the electrochemical device at a new harmonic frequency associated with the change in the minimum impedance value, The method according to claim 1, further comprising the following:

8. The step of determining the change in the minimum impedance value is: A step of detecting the frequency associated with the parasitic loss of the electrochemical device, A step of excluding the frequency associated with the parasitic loss when determining the change in the minimum impedance value, Equipped with, The method according to feature 7.

9. The method according to claim 1, characterized in that the electrochemical device comprises one of a half-cell battery, a cell battery, a plurality of batteries connected in parallel, or a plurality of batteries connected in series.

10. The method according to claim 1, characterized in that the energy flux comprises one of the following: charging current, discharging current, charging voltage, discharging voltage, charging power, or discharging power.

11. A step of controlling a portion of the energy flux at harmonic frequencies associated with the conductance value or susceptance value admittance of the electrochemical device. The method according to claim 1, further comprising the following:

12. The method according to 7, characterized in that the harmonic frequency associated with the minimum impedance value comprises the upper limit frequency of harmonics within the range associated with the minimum impedance value.

13. The method according to 7, characterized in that the leading edge portion is shaped according to the harmonic frequency corresponding to the lowest impedance value of the electrochemical device.

14. The method according to 13, wherein the energy flux further includes a main body portion including a steady-state charging portion, and the main body portion comprises a controlled magnitude charging current value following the leading edge portion.

15. The method according to 14, wherein the energy flux further comprises a trailing edge portion following the main body portion, and the trailing edge portion has a voltage value lower than the transient voltage corresponding to zero current flow in the electrochemical device.

16. A step of measuring the real impedance value and imaginary impedance value of the electrochemical device while the energy flux is applied to the electrodes of the electrochemical device. The method according to claim 1, further comprising the following:

17. A method for charging an electrochemical device, A step of accessing a harmonic profile that describes the relationship between the harmonic frequencies of the charging signal and the transfer of energy to or from an electrochemical device, A step of controlling the energy flux at the electrodes of the electrochemical device, wherein the energy flux includes repetitive pulses, each pulse including a leading edge portion shaped to correspond to a sine wave of the harmonic frequency, and the harmonic frequency is associated with the optimal energy transfer based on real and imaginary values ​​of the energy transfer at the electrodes. A method characterized by comprising:

18. A method for charging an electrochemical device according to claim 17, characterized in that the real value of the energy transfer is a real impedance, and the imaginary value of the energy transfer is an imaginary impedance.

19. A method for charging an electrochemical device according to claim 17, characterized in that the real value of the energy transfer is a conductance value, and the imaginary value of the energy transfer is a susceptance value.

20. Charging signal shaping circuit, A controller that controls a charge signal shaping circuit to generate a charge pulse for an electrochemical device using the relationship between the harmonic frequency components of a charge signal and impedance, wherein the charge pulse has a leading edge portion shaped sinusoidally based on the relationship between the harmonic frequency components of a charge signal and impedance, and the charge pulse further includes a body portion following the shaped leading edge portion, which includes a steady current defining the width of the charge pulse. A battery charging system characterized by having the following features.

21. A power supply that provides a power signal, wherein the power supply controls the charging signal shaping circuit to extract energy from the power signal and provide it to the charging signal. The battery charging system according to claim 20, further comprising the following:

22. The aforementioned charging signal shaping circuit is One or more first molded inductors that are communicating with a power source, A first switching device that communicates electricalally between the one or more first molded inductors and the electrodes of the electrochemical device, Equipped with, The battery charging system according to claim 20.

23. The aforementioned charging signal shaping circuit is One or more second molded inductors that are in electrical communication with the electrodes of the electrochemical device, A second switching device that communicates electricalally between the one or more second molded inductors and the power supply, Equipped with, The battery charging system according to claim 22.

24. The battery charging system according to claim 23, characterized in that the controller transmits a first control signal to the first switching device and a second control signal to the second switching device, and generates the charging pulse having the leading edge portion shaped based on the harmonic frequency associated with the lowest impedance value of the electrochemical device.

25. The power supply is a power supply that is either a voltage-controlled power supply or a current-controlled power supply. The battery charging system according to claim 22, further comprising the following:

26. An impedance measurement circuit communicating with the controller, wherein the controller transmits an impedance control signal to the impedance measurement circuit in order to obtain an impedance measurement value of the electrochemical device. The battery charging system according to claim 20, further comprising the following:

27. A charging signal shaping circuit comprising a first inductor and a first switching device, wherein the charging signal shaping circuit is in electrical communication with a battery cell, A controller that provides a pulse-width modulated control signal to a first switching device to shape the leading edge portion of a charge signal pulse for an electrochemical device generated from a control current to the first inductor, wherein the shape of the leading edge portion corresponds to a sine wave of a harmonic frequency related to the lowest impedance of the electrochemical device, A battery cell charging system characterized by comprising the following features.

28. The device further comprises a second switching device that is in electrical communication with a node that receives the aforementioned charging signal pulse, The battery cell charging system according to claim 27, characterized in that the controller provides a pulse width correction signal for activating the second switching device to further shape the leading edge portion of the charging signal pulse.

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